literature review - manure report 2010-05-l grieger pami... · literature review summary of manure...

June 30, 2010

21809R

Portage la Prairie, Manitoba

Literature Review

Summary of

Manure Treatment Technologies

and their Impact on the

Manure Phosphorus Balance

Joy Agnew, P.Eng., Ph.D.

Research Engineer

Lorne Grieger

Manager, Agricultural R & D

Harvey Chorney

VP Manitoba Operations

Acknowledgement

Thanks to the Manitoba Livestock and Manure Management Initiative

(MLMMI) for funding the project.

1

Table of Contents

Page

1. Introduction .................................................................................................................... 1

2. Description of Individual Treatment Technologies .......................................................... 2

2.1 Solid/Liquid Separation ......................................................................................... 2

2.2 Chemical Additives and Struvite Precipitation (in Combination with Separation) ... 8

2.3 Biological Treatment (Aerobic/Anaerobic/Anoxic) ................................................15

2.4 Composting and Biomass Conversion .................................................................19

2.5 Anaerobic Digestion .............................................................................................22

2.6 Vegetative Filter Strips .........................................................................................25

2.7 Constructed Wetlands ..........................................................................................28

2.8 Precision Manure Application ...............................................................................33

2.9 Other Technologies..............................................................................................37

3. Description of Multistage Treatment Technologies and Canadian Implementations.......40

3.1 Multiple Stage Treatment Systems ......................................................................40

3.2 Canadian Implementations ..................................................................................44

4. Evaluation of Treatment Technologies...........................................................................48

5. Recommendations and Research Gaps ........................................................................53

6. Manure Treatment Technologies Test Protocol Development .......................................55

Appendix I Evaluation Matrix ................................................................................................. 55

1

1. Introduction

New soil nutrient regulations mean farmers either have to reduce the phosphorus (P)

content of their manure or spread it over a larger area of land to satisfy regulations that

are based on a soil-P measurement and the expected P uptake of the planned crop.

There are three primary approaches to reduce the manure phosphorus surplus:

Feed management

Crop and land management

Manure management and treatment

Feed management involves improving feed efficiency and optimizing P content of the

feed. Since 36% to 73% of P fed to livestock is excreted, improving digestibility of P

could play a key role in reducing the P content in manure. This can be achieved by

adding enzymes such as phytase to feed rations. A significant amount of research is

being conducted in this area. This is because diet manipulation has the potential to

negatively impact animal growth and farm revenue, so these strategies are unlikely to be

adopted without rigorous testing.

Crop and land management strategies include reducing imports of synthetic fertilizer P,

maximizing crop removal of P, and expanding the land base for manure application. This

approach may involve adoption of remediation techniques for manure nutrient loaded

soils or practices such as vegetative mining. The potential for these techniques to

improve the manure-soil phosphorus balance in Manitoba requires further investigation.

Manure management and treatment technologies include solid/liquid separation,

chemical precipitation, anaerobic digestion, composting, vegetative filter strips,

constructed wetlands, and precision manure application. Some nutrient treatment

systems incorporate several technologies such as chemically aided separation with a

biological treatment of the effluent. The impact of these technologies on the manure

phosphorus balance and their potential for successful implementation in Manitoba is the

focus of this report. The conclusion of this report identifies key manure treatment

technologies that should proceed for intensive evaluation in Manitoba.

In addition, recommendations are made to assist in the development of a defined and

standardized set of evaluation criteria for manure treatment technologies. Specific test

methods and evaluation requirements can be used to objectively evaluate the manure

treatment systems in Manitoba in the future.

2

2. Description of Individual Treatment Technologies

In this section, basic information on seven individual treatment technologies is

summarized. Each technology includes a discussion of its primary removal mechanism,

important attributes, economics, and efficiency at removing or reducing P. The recent

research and testing of the technology is also presented, along with a list of references.

2.1 Solid/Liquid Separation

2.1.1 Primary Removal Mechanism (How Does it Work?)

Solid/liquid separation is considered primarily a physical process (unless aided by

coagulants and/or flocculants - see next section). The majority of P in manure is in the

solid fraction, so by separating the solid from the liquid, the liquid portion can be land

applied with lower P contamination risk. However, the solid portion will be high in P and

will need further treatment before use/disposal. Techniques to further treat the solids

(including composting) are discussed in later sections.

Separation technologies include:

Sedimentation: Works by allowing solid (large) particles to settle to the bottom of a

sedimentation basin by force of gravity. Works best for dilute wastewaters with

relatively large particle sizes. Sedimentation is the active mechanism for solids

separation in settling basins. Efficient sedimentation may require pretreatment or

addition of chemical amendments and is highly dependent on manure

characteristics. The most basic sedimentation or gravity settling systems include

anaerobic storage lagoons.

Screening: Slurry passes through a screen and solids collect on one side, the liquid

passes through to the other. Screening equipment includes inclined, vibratory, and

rotary configurations. Screening works best for slurries with relatively high solids

content with large particle sizes; however, it is inherently prone to plugging.

Efficiency is dependent on material particle size and technology used.

Centrifugation: Separates solid and liquid portions by centrifugal force. Can achieve

high efficiencies with flocculation but has high energy requirements. Configurations

include decanter centrifuge and a hydrocyclone. Pilot-scale centrifugation has been

demonstrated in Quebec and Manitoba (Puratone-IRDA, Trudelle, 2009).

Filtration (pressing): Usually a secondary process for dewatering solids portion and is

not considered a primary solid/liquid separation technology. Technologies include

roller, belt, screw, and filter (including straw) presses. An example of a chemically

aided filtration system is the Geotube(TM) (discussed in the next section).

3

2.1.2 Manure Species

Any manure species that exists in liquid or slurry form can be treated using solid/liquid

separation. In Canada, swine and dairy slurry are most often treated using these

technologies.

2.1.3 Important Attributes (Pros/Cons):

The solid portion after separation requires additional handling/treatment.

Solid/liquid separation is known to require less power if the manure is processed

soon after generation (do not let it sit for too long).

Settling basins do not treat or target P.

Multistage lagoons and settling basins are more efficient at settling solids and

stabilizing organic matter than single-stage systems.

Mechanical separation units are capable of throughputs of 26 to 7,800 gal/min (2 to

590 L/s) (Fleming and MacAlpine, 2003 in: Canadian Pork Council, 2005).

2.1.4 Effectiveness

Generally, more complex technologies tend to achieve better solids separation which

results in a lower P concentration in the effluent. Most methods of solid/liquid separation

are effective at removing particles >0.25 mm, resulting in P removal efficiencies between

35% and 75%. Smaller particles can be separated with the aid of flocculants. P removal

efficiencies for manure with the majority of particles in the 0.45 µm to 10 µm range are:

Settling: 38% to 40%

Settling with chemical amendment: 65% to 70%

Screening: 2% to 12%

Centrifugation: 43% to 68% (Cicek, 2009)

The separation technology also affects the N:P ratio of the effluent. Incoming effluent

typically has a ratio of 5:1 and the optimal ratio for plant uptake is 10:1 (Cicek, 2007).

The output ratio is 5 to 7:1 for screening and settling, 13:1 for settling with chemical

amendment, and 11:1 for centrifugation. Phosphorus is generally associated with very

small particles, which are most effectively removed by chemical addition and/or

centrifugation (Cizek, 2009).

2.1.5 Economics

High initial costs ($10,000 to $100,000) make advanced separation technologies

attractive only to larger farms (Kintzer and Moffitt, no date). These costs do not include

the cost of pumps, sumps, floor channels, and heated shelters, which may be required

for operation during winter months (Fleming and MacAlpine, 2003 in: Canadian Pork

Council, 2005). Operating and energy requirements can also be prohibitive for

4

mechanical separation. Capital and operating costs of settling basins and lagoons

(gravity settling) are relatively low and are very common in North American livestock

production. Settling tanks or basins cost about $33/sow space, or $9.21 to

$13.16/finisher space to construct for swine facilities (Lorimor and Edwards, 1998 in:

Canadian Pork Council, 2005). Additional machinery, such as a front-end or skid-steer

loader, is required for the operation of sedimentation basins.

The capital and annual costs of seven separation technologies were estimated for a 200

sow farrow to finish operation (Canadian Pork Council, 2005). Assuming typical energy

costs and market values, the most costly technology (on a $/pig marketed scale) was

centrifugation ($5.38/pig), followed by the belt press, screw press, settling basin, rotating

screen, and vibrating screen. The lowest cost alternative was the inclined screen

($1.22/pig) due to its relatively low capital cost ($25,000) and low operating costs.

Cicek (2007) noted that, of a settling basin, vibrating screen and decanter centrifuge, the

settling basin was the lowest cost method of separation for a 200 sow facility ($2.95/m3

total cost). However, the vibrating screen method was the lowest cost option for a 2,000

sow facility ($0.92/m3 total cost). The author also noted that different separation

technologies could offer added value benefits such as improving N:P ratio of the effluent,

reducing odour potential and allowing for further processing (i.e. composting).

2.1.6 Recent Research and Testing

Jorgensen and Jensen (2009) summarized five different solid/liquid separation methods

in use at commercial plants for separating swine manure and anaerobically digested

manure in Denmark. The technologies were: a decanting centrifuge, a screw press, a

rotating filter drum/screw press, and a screw press/vibrating filter. Different methods

resulted in significantly different P concentrations in the liquid effluent. The highest P

concentrations were found in decanting centrifuge samples (range 21.4-61.3 g P/kg

DM), which was significantly higher than the means of total P in other samples from

other separation technologies (range 2.2-12.7 g P/kg DM). Jorgensen and Jensen

(2009) also found that P in samples from a chemical treatment plus belt press separation

system were higher than in other separation only systems (screw press, rotating filter

drum and screw press, screw press and vibrating filter), indicating that chemical addition

did not always enhance separation. All systems were in use in commercial plants.

In the Netherlands, about 60 to 80 mechanical manure separation plants are in operation

and three high technology reverse osmosis slurry separation plants are in operation

(more are under construction). In France, about 600 pig farms are equipped with liquid

manure separation plants. About 60% of the separated manure is further treated by

biomechanical processes (aeration) and 25% is treated by physical-chemical processes

5

(chemically aided precipitation) and 15% is treated by thermal processes (Jorgensen

and Jensen, 2009).

Masse et al. (2007b) provided a review of microfiltration (0.1 µm to 5 µm) and

ultrafiltration (0.001 µm to 0.05 µm) (basically efficient solid/liquid separators) that can

isolate nutrients associated with particles such as P. Fouling of membrane pores caused

issues in most cases. Although most studies on filtration in Canada are on a lab scale, a

membrane pilot was installed on a pig farm in Canada by the company Purin Pur. The

system used a screen for coarse suspended solids (SS) removal, tubular ultrafiltration

membranes for SS and P retention, and tubular reverse osmosis (RO) membranes for

the final treatment. The system reportedly produced “pure water” but no actual data was

supplied. The evaluated cost was $5.97/m3; however, the pilot was not extensively used

because the membranes were rapidly fouled.

Melse and Verdoes (2005) evaluated four farm scale liquid pig manure treatment

systems in use in the Netherlands, two of which utilized mechanical separation (straw

filtration and screw press plus micro filtration). The straw filtration system treated liquid

manure from sows and fattening pigs (1,600 tonne of manure/year) at a commercial

system in the Netherlands. The straw filter was 5 cm thick on a trenched concrete floor

located inside a greenhouse enclosure to enhance evaporation by solar radiation.

Approximately 5 kg of straw was required for each tonne of treated manure. The straw

acted as a cake filter; directly after start-up, small amounts of solids were retained by the

straw, but as time passed the solids accumulated in the straw forming a cake which

retained the solid particles very well. The effluent from the straw filter was further

processed in subsequent settling chambers. After four weeks of operation, the filtration

capacity of the straw bed was drastically reduced by accumulation of solids. The straw

was removed and treated as solid manure. The straw filtration system had the lowest

investment and operating costs of the four technologies studied in the paper. The

incoming liquid manure had a total P content of 1.8 g/kg and the treated water (after

filtration and settling) was <0.001 g/kg. The majority of the P was recovered in the spent

straw and the sludge at the bottom of the settling tanks. Adviesbureau et al. (1998) also

reported on straw filter efficiency at removing phosphate from swine manure and found

similar efficiencies as centrifuge and settling processes. Past experience with straw

filtration was gathered by Kalyuzhnyi et al. (2000); PDV (1994) and Priem (1980) in:

Melse and Verdoes (2005).

Slurry lagoons and pits allow for primary biological treatment while providing storage for

manure and solids separation via sedimentation. Lagoons allow settling of solids

(although they are usually redistributed prior to application via agitation), help stabilize

organic matter, and sometimes there is a net water loss due to evaporation, reducing the

volume to be handled. Settling basins for solids removal have been investigated for

swine and bovine open lot runoff in the US (Woerner and Lorimor, no date). Solids from

6

beef feedlots settled within 10 min., but settling characteristics of hog manure were

highly variable, sometimes taking more than 100 min. to settle the largest particles.

Properly designed and managed solids settling basins should remove about 30% of the

N and P from the runoff from swine lots and approximately 80% of each from bovine lot

runoff (Woerner and Lormor, no date).

7

References

Adviesbureau, V.R. 1998. Phosphate recovery from animal manure: the possibilities in the

Netherlands. CEEP, November, 1998. Available at: http://www.nhm.ac.uk/research-

curation/research/projects/phosphate-recovery/VanRuiten.pdf Accessed: April 20, 2010.

36 pp.

Canadian Pork Council. 2005. Practices and Technologies Aimed at Reducing

Environmental Impacts from Hog Production: Scientific and Economic Evaluation. ISBN

#0-9696896-8-3.

Cicek, N. 2009. Overview of liquid manure treatment options. Manitoba Livestock Manure

Management Initiative (MLMMI). Achieving Manure Phosphorus Balance in Manitoba.

Workshop: November 30-December 1, Winnipeg, Manitoba.

Jorgensen, K., L.S. Jensen. 2009. Chemical and biological variation in animal manure

solids separated using different commercial separation technologies. Bioresource

Technology 100:3088-3096.

Kintzer, B., D. Moffitt. No date. Physical Manure Treatment (Solids Separation).

Phosphorus Best Management Practices Factsheet. Developed by SERA-17, Minimizing

Phosphorus Losses from Agriculture. Available online http://sera17.ext.vt.edu/ Accessed:

April 20, 2010.

Masse, L., D.I. Masse, Y. Pellerin. 2007b. The use of membranes for the treatment of

manure: a critical literature review. Biosystems Engineering 98:371-380.

Melse, R.W., N. Verdoes. 2005. Evaluation of four farm-scale systems for the treatment of

liquid pig manure. Biosystems Engineering 92(1):47-57.

Trudelle, M. 2009. Environmental sustainability and hog production in Quebec: Current

status of manure treatment/processing options for phosphorus management. Manitoba

Livestock Manure Management Initiative (MLMMI). Achieving Manure Phosphorus

Balance in Manitoba. Workshop: November 30-December 1, Winnipeg, Manitoba.

Woerner, B., J. Lorimor. No date. Alternative treatments to minimize water pollution from

open animal feedlots. Iowa State University. Available online:

http://www.agronext.iastate.edu/immag/info/epaalttech.pdf. Accessed: April 20, 2010.

http://www.nhm.ac.uk/research-curation/research/projects/phosphate-recovery/VanRuiten.pdf


http://sera17.ext.vt.edu/

http://www.agronext.iastate.edu/immag/info/epaalttech.pdf

8

2.2 Chemical Additives and Struvite Precipitation (in

Combination with Separation)


Flocculation, coagulation, and precipitation prior to solid/liquid separation improve the

manure separation efficiency. Chemical additives such as coagulants and flocculants

assist in solid/liquid separation by forming larger particles that are easier to settle.

Flocculation is the formation of an unstable solution whereby aggregation of particles

occurs. Organic polymers induce bridging between larger particles, which induces

flocculation. Coagulants (metal salts) promote the aggregation of small particles through

charge neutralization (Hjorth and Christensen, 2007). Some additives also help

precipitate soluble forms of P, resulting in removal of both soluble and insoluble forms of

P. Additives (organic polymers) include Al(SO4)3 (alum), Ca(OH)2 (lime), FeCl3, and

aluminum chloride. Garcia et al. (2009) experimented with the natural flocculant chitosan

to improve screening of dairy manure.

Ammonium magnesium phosphate (struvite) is a slow release fertilizer used in

horticulture and fisheries. Phosphorus in manure can be precipitated as struvite if proper

ratios of ammonium and magnesium are also present (Mg is usually limiting nutrient). A

typical Mg: PO4 ratio is 1.6:1. Struvite production is highly dependent on the pH of the

solution. After struvite production, precipitation, and separation, the liquid effluent has a

lower soluble P content and can be land applied to a smaller area and meet P

regulations.

Another solids/P separation system, the Geotube(TM), relies on chemically aided filtration.

The Geotube bag dewatering system involves treatment of the manure with coagulants

and flocculants and placement in large bags (30 ft x 100 ft, for example) where water is

allowed to seep out. Four to eight weeks later, the bag is peeled back and the solids are

removed (and further treated). The effluent (water that seeps out) can be reused in the

barn (Johnson, 2004).


The addition of organic polymers and metal salts to promote flocculation and coagulation

is effective for all liquid manures. Aluminmum chloride (alum) has also been reported to

be effective for treating solid poultry litter which has a high soluble P content. Liquid or

solid alum can be sprayed/broadcasted in the production building between flocks.

Aluminum chloride has been reported to be effective for hog manure by chemically

binding P to prevent runoff (Smith, no date).

9

2.2.3 Important Attributes (Pros/Cons)

Chemical addition to aid separation is generally low cost and effective, but the

amount and timing of chemical addition needs to be optimized and carefully

managed. Also, users must deal with the recovery of the precipitate. These solids

must be chemically or biologically treated to release phosphates and make them

available for recovery processes like precipitation or absorption (Adviesbureau,

1998).

Research has shown that soluble P is preferentially partitioned in the liquid fraction

following separation; therefore, chemical precipitation works better when larger solids

are already removed (Burns, 2009).

Johnson (2004) concluded that the Geotube technology provides an economical

means for the smaller (<1,000 head) dairies and most swine producers to meet

nutrient management needs.

Barrington et al. (2004) stated that precipitation can result in a better balance of

nutrients for plant uptake.

Precipitation of struvite involves optimizing Mg:P ratio, acidity, retention time,

temperature, etc. (Adviesbureau, 1998)

Struvite has potential to create blockages in supply lines, but it is a good source of

plant nutrients because it releases them slowly and has low solubility (Beal et al.,

1999).

2.2.4 Effectiveness

Burns et al. (2003) reported a 60% to 91% soluble P reduction due to chemical

amendment addition in a lab setting. The authors noted that P reduction seemed to be

more effective for manure from primary cell than secondary cell. Testing on swine

concrete storage and deep pit systems showed that struvite production and precipitation

resulted in a 90% reduction in soluble P content and 10% recovery of total P in solids

fraction (Burns, 2009). Burns and Moody (2002) reported that 90% of soluble P was

removed from field scale swine manure trials using struvite precipitation.

Johnson (2004) reported that the Geotube system reportedly had a total P reduction of

98.2% (both soluble and insoluble P) during full scale testing at a 10,000 head swine

finishing facility (P2O5 went from 2.3 lb/1,000 gal to 0.24 lb/1,000 gal). The overall P

removal efficiencies from testing at swine and cattle facilities exceeded 90%.

Addition of a polymer to manure running through a centrifuge separator can increase the

removal of P from swine manure from 66% to 75% (HPSFG, 1994 in: Canadian Pork

Council, 2005).

10

2.2.5 Economics

For treatment of poultry litter, alum needs to be applied 5% to 10% by weight and costs

$250/ton (require approx 2 tons/flock) (Moore, no date). For treatment of swine effluent,

aluminum chloride costs $1/133 gallons ($0.10 to 0.151/lb) while handling equipment

(pumps, etc.) will cost $1,500 to $3,000. Aluminum chloride should be applied at a 1:1

molar ratio (0.75% by volume) (Smith, no date).

The cost of struvite recovery system was reported to be $8.88/finished pig for a

10,000 head/year facility or 3.5 cents/l of manure treated slurry (Burns, 2009 workshop).

Walker and Wade (2010) presented the economics of solid/liquid separation

technologies in conjunction with chemical amendments for production scale swine

facilities in Illinois. The technologies included: inclined gravity screen/roll press separator

operated with a polyacrylamide (PAM) assisted continuous gravity belt thickener or a

PAM assisted inclined stationary gravity screen separator, each in tandem with an

inclined stationary gravity screen roll press separator. The gravity belt thickener

achieved 52.3% reduction of total P and the gravity screen achieved 60.5% total P. The

cost of separation with the gravity belt system was 0.474 cents/l of raw slurry. The

separation cost with the gravity screen system was 0.402 cents/l of raw slurry.

Application costs for irrigating the separated effluent from either system added another

0.061 cents/l of raw slurry.

The Canadian Pork Council (2005) discussed the costs associated with combining the

technology of chemical addition with separation techniques. These costs include the

costs of chemicals and labour or equipment for adding the chemicals. Polyacrylamide

costs $29/kg and can be incorporated at a rate of 5 mg/l of waste (Watts et al., 2002 in:

Canadian Pork Council, 2005). For a 5,000 head space finishing operation producing

0.004 m3 of waste/animal/day, the annual chemical cost of adding the polyacrylamide is

$1,058.50.

Geotube costs were $2.64/1,000 l for chemical and $6.60/1,000 l for the bag. Johnson

(2004) reported that the costs for this system, including equipment, engineering,

installation, chemicals, and application totalled $14,810 for a 10,000 head swine

finishing facility (45 ft x 100 ft bag). Chemical costs for the swine facility averaged $5 to

$10/day.


The Geotube technology was tested on a 10,000 head swine finishing facility in Indiana

(Johnson, 2004). Effluent from primary storage was amended with cationic polymer and

coagulant (AlSO4). The system was also tested on an Alabaman dairy (150 cows). Liquid

ferric sulphate was added to assist with separation and nutrient removal. Solids

11

remained in the bag until it was filled then they can be land applied. The 30 ft x 100 ft

bag could potentially hold the solids generated from between 2 million and 5 million

gallons (TS of influent between 0.5% and 1%). Szogi et al. (2006) discussed a similar

solids dewatering mechanism that utilized polymer addition and filter bags to makes

solids (and P) transport more economical.

Beal et al. (1999) researched forced precipitation of struvite from swine manure on a lab

scale. They noted that the optimal pH for struvite production was between 9 and 9.5

because orthophosphate (plant available P, required for struvite) does not exist in acidic

environments. However, if the pH is greater than 10, NH4 is unavailable for reaction.

They also found, during lab scale research, that the optimum temperature and mixing

time was 35°C and 15 min. They noted that P removal by struvite precipitation was more

efficient using anaerobically digested swine manure than raw swine manure (anaerobic

digestion brings more of the Mg ion into solution, improving struvite production). In a

similar lab scale study, Burns et al. (2003) discussed forced precipitation of struvite from

swine wastewater. They concluded that a solution pH between 7 and 11 limits struvite

solubility, increasing precipitation and that organic matter (OM) can increase solubility of

struvite (so OM should be removed before precipitation). Also, agitation prior to land

application can raise pH (due to CO2 stripping), enhancing struvite production. The

particle size distribution of struvite is similar to sand so mechanical separation is an

option. Finally, a retention time of 10 minutes was optimal for struvite production (longer

retention times produced more struvite but were impractical).

Jin and Wen (2009) enhanced struvite precipitation using microwave pretreatment of

dairy manure (lab-scale in Virginia). A temperature of 135°C for 26 min optimized

orthophosphate release while 147°C and 25.3 min. optimized methane production.

Anaerobic digestion of dairy manure is commonly limited by slow fibre degradation while

struvite precipitation is limited by the availability of orthophosphate. This project studied

the possibility of using microwave-based thermo-chemical pretreatment to

simultaneously enhance manure anaerobic digestibility (through fibre degradation) and

struvite precipitation (through P solubilisation).

DeBusk et al. (2008) discussed chemical P removal from dairy slurry using polymer

addition to enhance floc size and improve P removal. In the field scale trial in Virginia

(1,8360 m3 of dairy manure with 1.2% TS and 157 mg P/l), 200 mg/l of AlCl3 and

100 mg/l of Superfloc 4512 polymer was added. Approximately 84% of total P was

sequestered in a P-rich sludge. They estimated that the total cost of treating manure and

transporting P rich sludge was $4.09/m3.

Adviesbureau et al. (1998) summarized several chemical additive strategies for veal

manure and swine manure in the Netherlands. “Dephosphorization”, or adding milk of

lime to aeration tanks, resulted in effluent concentrations to go from 300 mg P/l to

12

30 mg P/l for veal manure. After addition, calcium phosphate forms, settles, and is

passed with surplus sludge. Crystallisation involves crystallisation of CaP2O5 on an inert

carrier in a fluidised bed. This process reportedly resulted in a purer phosphate product

that was marketable and could remove 90% of incoming phosphate. Greaves et al.

(1999) also reviewed the prospects for the recovery of P from animal manures in the UK.

Several P crystallisation processes are fully operational in the UK, recovering calcium

phosphate pellets, apatite, and HAP.

Harris et al. (2008) discussed P recovery using crystallisation in a fluidized bed (bench

scale, dairy manure wastewater) in Florida. Results of this study verify that P can be

recovered from flushed dairy manure wastewater in the form of calcium phosphate.

However, the authors stated that only dissolved inorganic P is recoverable with this

method. Hence, any processing of the wastewater that mineralizes organic P (e.g. AD)

would improve P recovery efficiency.

Kunz et al. (2009) discussed technologies to treat liquid swine slurry using polymers to

aid in separation in Brazil. Synthetic organic polymers have been used for animal

manure solid/liquid separation. The most representative product is PAM which has been

reported to remove between 80% and 95% of TSS in swine manure. Other natural

organic flocculants include chitosan (extracted from crab shell) and natural extracts from

black wattle. The authors also estimated the economics of a manure treatment system

including initial investment, fixed costs, operating costs (labour, energy, chemicals,

maintenance, sludge disposal), and potential revenue (energy from biogas, sludge

fertilizer, carbon credits).

Oh et al. (2003 and 2005) investigated the use of liquid aluminum sulphate (alum) in

conjunction with a mechanical screw press separator on P removal of dairy manure in

Tennessee. The authors noted that the ability to partition P into the recovered solids

would increase the feasibility of transporting P off the farm. The combined retail cost for

alum and polymer addition at optimal rates was estimated to be $2.63/1,000 l of treated

slurry. The results indicated that a cationic polymer used in conjunction with alum

amendment can effectively partition P into the press cake during mechanical solids

separation.

In Canada, Barrington et al. (2004) has conducted lab scale research on precipitation of

swine manure, showing removal efficiencies similar to those found in the US and

Europe.

13

References




36 pp.

Barrington, S.F., S. Kaoser, M. Shin, J.B. Gelinas. 2004. Precipitating swine manure

phosphorous using fine limestone dust. Canadian Biosystems Engineering 46:6.1-6.6.

Beal, L.J., R.T. Burns, K.J. Stadler. 1999. Effect of anaerobic digestion on struvite

production for nutrient removal from swine waste prior to land application. ASAE Annual

International Meeting. Paper No. 99-4042.

Burns, R.T., L.B. Moody. 2002. Phosphorous recovery from animal manures using

optimized struvite precipitation. In: Proceedings of Coagulants and Flocculants: Global

Market and Technical Opportunities for Water Treatment Chemicals, Chicago, Illinois. May

22-24.

Burns, R.T., L.B. Moody, I. Celen, J.R. Buchanan. 2003. Optimization of phosphorous

precipitation from swine manure slurries to enhance recovery. Water Science and

Technology 48(1):139-146.

Burns, R.T. 2009. Phosphorus reduction and recovery from animal manures. Manitoba

Livestock Manure Management Initiative (MLMMI). Achieving Manure Phosphorus

Balance in Manitoba. Workshop: November 30-December 1, Winnipeg, Manitoba.

DeBusk, J., J. Arogo Ogejo, K.F. Knowlton, N.G. Love. 2008. Chemical phosphorus

removal for separated flushed dairy manure. ASABE Annual International Meeting. Paper

No: 08-4499.

Garcia, M.C., A.A. Szogi, M.B. Vanotti, J.P. Chastain, P.D. Millner. 2009. Enhanced

solid/liquid separation of dairy manure with natural flocculants. Bioresource Technology

100:5417-5423.

Greaves, J., P. Hobbs, D. Chadwick, P. Haygarth. 1999. Propects for the recovery of

phosphorus from animal manures: a review. Environmental Technology 20:697-708.

Harris, W.G., A.C. Wilkie, X. Cao, R. Sirengo. 2008. Bench-scale recovery of phosphorus

from flushed dairy manure wastewater. Bioresource Technology 99:3036-3043.

Hjorth, M., M.L. Christensen. 2008. Evaluation of methods to determine flocculation

procedure for manure separation. Transactions of ASABE 51(6):2093-2103.



14

Jin, Y, Z. Hu, Z. Wen. 2009. Enhancing anaerobic digestibility and phosphorus recovery of

dairy manure through microwave-based thermochemical pretreatment. Water Research

43:3493-3502.

Johnson, V. 2004. A system for manure treatment and phosphorus control on small dairy

and swine farms. ASABE Annual Intersectional Meeting. Paper No.: 04-4167.

Kunz, A., M. Miele, R.L.R. Steinmetz. 2009. Advanced swine manure treatment and

utilization in Brazil. Bioresource Technology 100:5485-5489.

Moore, P. No date. Treating Poultry Litter with Aluminum Sulfate (Alum). Phosphorus Best

Management Practices Factsheet. Developed by SERA-17, Minimizing Phosphorus

Losses from Agriculture. Available online http://sera17.ext.vt.edu/ Accessed: April 20,

2010.

Oh, I., L.B. Moody, I. Celen, J. Lee, R.T. Burns. 2003. Optimization of phosphorus

partitioning in dairy manure using aluminum sulphate with a mechanical solids separator.

ASABE Annual International Meeting. Paper No.: 03-2266.

Oh, I., R.T. Burns, L.B. Moody, J. Lee. 2005. Optimization of phosphorus partitioning in

dairy manure using aluminum sulphate with a mechanical solids separator. Transactions

of ASABE 48(3):1235-1240.

Smith, D. No date. Treating Swine Manure with Aluminum Chloride. Phosphorus Best

Management Practices Factsheet. Developed by SERA-17, Minimizing Phosphorus

Losses from Agriculture. Available online http://sera17.ext.vt.edu/ Accessed: April 20,

2010.

Szogi, A.A., M.B. Vanotti, P.G. Hunt. 2006. Dewatering of phosphorus extracted from

liquid swine waste. Bioresource Technology 97:183-190.

Walker, P.M., C.A. Wade. 2010. Comparison of the effectiveness and economic costs of

two production scale polycrylamide assisted solid/liquid separation systems for the

treatment of liquid swine manure. Applied Engineering in Agriculture 26(2):299-305.



15

2.3 Biological Treatment (Aerobic/Anaerobic/Anoxic)


Commonly used in wastewater treatment facilities, biological treatments include passing

waste through alternating anaerobic, anoxic, and aerobic zones to transform P and allow

it to be removed efficiently. The ability of activated sludge microflora to take up dissolved

P beyond the requirements for growth has been appreciated since the 1950s. Enhanced

Biological Phosphorous Removal (EBPR) is a process designed to enhance the natural

ability of certain bacterial strains to accumulate large quantities of dissolved inorganic P

and store it in insoluble polyphosphate granules. The basis of this technology is to

introduce an anaerobic front-end stage to the standard activated sludge sewage

treatment system followed by secondary and tertiary anoxic or anaerobic stages

arranged to create an alternating system of aerobic and anaerobic conditions (Greaves

et al., 1999). The goal of biological treatment systems is to oxidize dissolved and

particulate biodegradable constituents of manure into acceptable end products and to

transform or remove N and P. They make use of naturally occurring microorganisms to

degrade manure in the presence of oxygen (aerobic), the absence of oxygen

(anaerobic), or the presence of chemically available oxygen only (anoxic). Aerobic

systems uptake P and bind it in organic forms. Depending on the technology, air can be

supplied using bubble or surface aerators.

Aerated batch reactors can also be classified as biological treatment systems. These are

storage tanks that are either naturally or mechanically agitated to increase oxygen

content and aerobic microbial activity to stabilize and oxidize organic matter. These

systems are mainly used for N reduction and stabilization of nutrients and are generally

not effective at P removal because constant agitation does not allow settling of solids.

Most of the available research on the effectiveness of aeration tanks at removing P is at

the lab scale.


Again, this type of biological treatment is suitable for any type of liquid waste (including

manure).


Because biological treatment systems rely on sensitive microbial populations, control of

process parameters is essential to performance. The heterogeneous nature of most

manure makes controlling these parameters difficult. Highly skilled personnel are

required to operate biological treatment systems.

16

2.3.4 Effectiveness

This process is widely used in sewage treatment to reduce P concentration in the

effluent, frequently by 80% to 90%, often below 1 mg P/l (Greaves et al., 1999).

2.3.5 Economics

High capital costs and maintenance requirements make these complex systems

attractive to large-scale operations only. Aerated batch reactors have lower costs but are

not as efficient at P removal.


Maranon et al. (2008) discussed an anoxic/anaerobic treatment of liquid cattle slurry on

a lab scale in Spain and reported a 92% total P reduction (0.696 to 0.058 g/l). The

anoxic process was carried out at 30°C in a completely mixed reactor, the anaerobic

process in an upflow anaerobic sludge blanket at 37°C and the oxic (aerobic) treatment

in another completely mixed reactor at 20°C.

Ra et al. (1999) used a bench scale wastewater treatment system to optimize the

oxidation reduction potential to remove nutrients from swine wastewater (combination of

anoxic/oxic and anoxic reaction chambers). The system was controlled in real time using

the nitrogen break point to ensure sufficient organic carbon was available for

denitrification. Using this as a control point, consistently high reduction of combined

organic C, N, and P (97%) concentrations were observed, despite the large fluctuations

of animal wastewater characteristics. An external carbon source was not required

because internally available OM was efficiently used. The paper includes detailed

discussion of P uptake/release cycles in anoxic, anaerobic, and aerobic zones including

the uptake during aerobic stage and subsequent release during anaerobic stage.

Essentially, inorganic P is released from cells during anaerobic phase as a result of

polyphosphate hydrolysis. During aerobic phase, soluble P is taken up by bacteria that

synthesize polyphosphates.

Ndegwa et al. (2003) examined the timing of solids/liquid separation during aeration to

achieve soluble orthophosphate (ortho-P) reduction from liquid swine nursery manure.

These tests were done in Oklahoma on a lab scale. The treatments included: separation

before aeration, separation during aeration, and no separation. More ortho-P was

converted to nonsoluble species when separation occurred during aeration (92%) than

with before (87%) or none (84%). Total P reduction was 80%, 70%, and 60% for mid,

pre, and no separation. The middle treatment also improved removal of total P from

liquid after an overnight sedimentation process. Authors noted that Luo et al. (2001)

showed that as much as 76% of soluble ortho-P can be removed using low-level

aeration for 24 hours. The authors also discussed the effect of length of aeration on

17

organic P content. The conclusion was that the longer the manure was aerated, the

higher the organic P content was, presumably due to microbial biomass production.

Luo et al. (2002) summarized a lab-scale aeration reactor to study the effect of

intermittent and continuous aeration of swine manure on soluble orthophosphate content

in Minnesota. Within a 24 hour aeration period, 75% of soluble orthophosphate was

removed from solution for both treatments (intermittent and continuous), suggesting that

the P removal efficiency was independent of aeration schemes to energy could be saved

while maintaining the removal efficiency.

18

References



Luo, A., J. Zhu, P.M. Ndegwa. 2002. Removal of carbon, nitrogen and phosphorus in pig

manure by continuous and intermittent aeration at low redox potentials. Biosystems

Engineering 82(2):209-215.

Maranon, E., L. Castrillon, L. Garcia, I. Vazquez, Y. Fernandez-Nava. 2008. Three-step

biological process for the treatment of the liquid fraction of cattle manure. Bioresource


Ndegwa, P.M., J. Zhu, A. Luo, D.W. Hamilton. 2003. Enhanced phosphorus removal from

swine-nursery manure in aerated batch reactors. Transactions of the ASABE 46(3):797-

803.

Ra, C.S., K.V. Lo, D.S. Mavinic. 1999. Control of a swine manure treatment process using

a specific feature of oxidation reduction potential. Bioresource Technology 71:117-127.

19

2.4 Composting and Biomass Conversion


Composting is an aerobic, thermophilic biological process. Because the process does

not reduce the P content of the material, it is primarily a treatment to reduce the volume

of waste, lowering the transportation cost. The microbial activity that occurs during the

composting process reduces water-soluble P content by 50%, but the total P content

remains the same. Also, the P remains plant available, which is important when using

compost as a fertilizer.

Biomass conversion is essentially the same as composting but utilizes fly larvae

(maggots) to break down the organic matter instead of microorganisms. These systems

can be placed directly in barn (swine, poultry) and achieve manure mass reduction up to

50%. Main benefit of these systems is that prepupae accumulate large amounts of Ca

and P in tissues so overall P is actually reduced during the process. There is some

uncertainty as to whether this system can be sustained in the Canadian climate

(Buckley, 2009), but research is underway at the University of Guelph. Research

reviewed in Lorimor et al. (2006) revealed that only fresh, aerobic manure is suitable for

fly larvae growth.


Any solid or semisolid manure can be composted. Composting is often a secondary

treatment for the solids portion of a solid/liquid separation system.


Composting effectively reduces the volume of waste (and cost to transport to P deficient

areas). However, N loss is typically high, further unbalancing the N:P ratio. Composting

may result in release of soluble P depending on species or management (Buckley,

2009). Currently there is no stable market value for finished compost, making it difficult

to justify a large scale operation based solely on potential revenue from the end product.

2.4.4 Effectiveness

In one study, P runoff from a field applied with composted manure was 50% lower than

from raw manure (Sikora and Preusch, no date). Numerous resources state that the

mass and volume reduction due to composting is approximately 50%, depending on the

feedstock and type of management.

20

2.4.5 Economics

Depending on the size and type of operation, capital costs can be high (equipment,

composting pads, etc.). For simple pile composting, capital equipment would include a

tractor with front-end loader ($100,000). These are commonly already owned by the

farm. Self-propelled and pull-type windrow turners cost approximately $125,000 and

$25,000, respectively (Canadian Pork Council, 2005).

The complexity of the composting system (base, roof, housing) will depend on the

environmental conditions such as proximity to surface/ground water sources, annual

rainfall, etc. A concrete or asphalt base to control leaching can cost up to $13.50/m2

(Buckley, 2004 in: Canadian Pork Council, 2005). A base of compacted clay and gravel

is less expensive and runoff treatment may only need to be a vegetated filter strip. The

need for a roof will increase the capital costs by $71/m2 to prevent rainfall from reaching

the compost (Canadian Pork Council, 2005).

The capital costs for in-vessel composting are significantly higher due to the increased

amount of equipment. A compost turner with carriage ($103,000) is needed, plus an

aeration system ($24,000) (Canadian Pork Council, 2005). An alternative in-vessel

composting system called the Ag-Bag Composting System (Pacific Forage Bag Supply,

Delta, B.C.) has a capital cost of approximately $60,000 for the Ag-Bagger loading

equipment and material costs (bags, fans, aeration line, etc.) of approximately $13 per

tonne of compost-ready material.

Proper composting also requires management and maintenance (labour). The estimated

cost of labour for pile and windrow composting is $6,000 (to process 7,000 tons of

manure in a year). The labour required for in-vessel composting would be slightly lower.

In some cases, amendment material may be required (purchased) to mix with the solid

manure to reach optimum composting conditions. Bulking agents such as straw or

sawdust can cost $14 to $15/tonne of manure.


Parkinson et al. (2004) discussed the effect of turning regime and weather conditions on

N and P losses during aerobic composting of cattle manure in UK. The two regimes

included front-end loader turning or mixing using a rear discharge manure spreader. The

compost piles were approximately 12 m3 to 15 m3 in size. The piles were turned once or

three times during the four month composting period. Leachate losses of soluble P were

not affected by turning regime. Total P losses were 28.2% when turned once and 27.4%

when turned three times, but this difference was not statistically significant. The

concentration of P (g/kg) rose over composting period due to consumption of organic

matter.

21

References

Buckley, K.E. 2009. Overview of solid manure treatment options. Manitoba Livestock

Manure Management Initiative (MLMMI). Achieving Manure Phosphorus Balance in

Manitoba. Workshop: November 30-December 1, Winnipeg, Manitoba.



#0-9696896-8-3.

Parkinson, R., P. Gibbs, S. Burchett, T. Misselbrook. 2004. Effect of turning regime and

seasonal weather conditions on nitrogen and phosphorous losses during aerobic

composting of cattle manure. Bioresource Technology 91:171-178.

Lorimor, J., C. Fulhage, R. Zhang, T. Funk, R. Sheffield, D.C. Sheppard, G.L. Newton.

2006. Manure management strategies and technologies. In: Animal Agriculture and the

Environment: National Center for Manure and Animal Waste Management White Papers.

J.M. Rice, D.F. Caldwell, F.J. Humenik, eds. St. Joseph, MI: ASABE Pub. Number

913C0306. Pp. 409-434.

Sikora, L.J., P. Preusch. No date. Composting Effects on Phosphorus Availability in

Animal Manures. Phosphorus Best Management Practices Factsheet. Developed by

SERA-17, Minimizing Phosphorus Losses from Agriculture. Available online

http://sera17.ext.vt.edu/ Accessed: April 20, 2010.


22

2.5 Anaerobic Digestion


During anaerobic digestion (AD), organic material is biologically broken down to form a

biogas of carbon dioxide and methane. Anaerobic digestion is used primarily as a

method to generate energy from waste but it can also be considered a biological waste

treatment method. During the digestion process, most nutrient levels (including P)

remain unchanged, but most P settles in the sludge in unmixed digesters. Unlike

composting, the overall volume of waste does not decrease significantly during

anaerobic digestion.


Most digesters are designed for liquid or slurry systems, but dry fermentation techniques

can be used for solid manure. High solids digestion is less common but some full scale

facilities exist in Germany and Alberta.


The main benefit of anaerobic digestion is the generation of revenue from energy

production. In fact, many multistage manure treatment systems include anaerobic

digestion as a step to generate some revenue. The main drawback of the technology is

the requirement to deal with sensitive microbial communities, making management

difficult. Also, the sludge or digestate requires further processing to stabilize P because

P content does not change significantly during the AD process. The form of P generally

shifts from organic to inorganic during the digestion process, resulting in increased plant

availability of the nutrient but increasing the susceptibility to loss by leaching, runoff and

volatilization (Aldrich, 2005 in: Cicek, 2007).

2.5.4 Effectiveness

Cold climate anaerobic digestion may be a problem as the energy required to maintain

optimal (mesophilic) temperatures can be very high. Biogas production can be boosted

by adding high energy cosubstrates such as food waste or fats/oils/grease. Again, AD

does not alter the P content of the material, but some research has shown that

dissolved, unreactive P mineralizes during the process. With efficient solid/liquid

separation, P can be efficiently retained in the solid fraction.

2.5.5 Economics

Anaerobic digestion systems have prohibitively high capital costs ($100,000+) and

relatively high operation and maintenance costs. These high costs can be offset by

23

generation of revenue from energy production, but not all provinces have tariff programs

that make green energy production sustainable.


Gungor and Karthikeyan (2008) discussed the effect of AD on P forms and extractability

by analyzing six full-scale on-farm digesters in Wisconsin. They noted that in the influent

dairy manure, 12% of total P was dissolved while in the effluent, 7% of total P was

dissolved. Dissolved, unreative P (polyphosphate and organic P) mineralized during AD

and became part of solid fraction. All farms utilized mechanical solid/liquid separation

after digestion. Liquids were stored in a lagoon and land applied while the solid portion

was reused for bedding. On the six farms, the anaerobic digestion technologies included

mixed plug flow, plug flow, and completely mixed reactors. Additional research is

necessary to specifically examine the mechanism causing an increase in P solid phase

stability after AD. This mechanism could be exploited for the design of on-farm AD

systems to maximize P recovery from animal manures.

24

References

Cicek, N. 2007. Assessment of Potential Hog Manure Processing Strategies in Manitoba.

In: A Report on Current Knowledge of Key Environmental Issues Related to Hog

Production in Manitoba. D. Flaten, K. Wittenburg, Q. Zhang, Clean Environment

Commission. October, 2007.

Gungor, K., K.G. Karthikeyan. 2008. Phosphorus forms and extractability in dairy manure:

A case study for Wisconsin on-farm anaerobic digesters. Bioresource Technology 99:425-

436.

25

2.6 Vegetative Filter Strips


Vegetative filter strips (VFS) can be considered a physical, chemical, and biological

treatment system. A VFS is a band of planted or indigenous vegetation situated down

slope of cropland or animal production facilities that provides localized erosion protection

and contaminant reduction (Woerner and Lorimor, no date). The vegetation treats runoff

through filtration, adsorption, settling, and infiltration. VFSs provide an opportunity for

runoff and pollutants to infiltrate into the soil profile, allow deposition of total suspended

solids, enhance filtration of suspended sediment by vegetation, provide adsorption on

soil and plant surfaces, and enhance adsorption of soluble pollutants by plants (Woerner

and Lorimor, no date). VFSs are increasingly being viewed as practical, low-cost

management options for improving the quality of surface runoff from pollutant sources as

well as providing erosion protection.

There are two types of VFSs: channelized flow and overland flow (preferred). Overland

flow systems allow a uniform loading of waste (across the width of the VFS) at a

relatively shallow depth (<1.5 in). The optimum retention time is two hours and the

optimum length will depend on slope and typical rainfall/runoff.


This treatment system is suitable for any liquid system. It works well for treating runoff

from open lot feedlots and areas between liquid application sites and surface waters.


VFSs are good for removing non-soluble nutrients (P, NH4) because they efficiently trap

sediment. Some form of solid settling (pre-treatment such as a settling basin) should

precede a VFS to reduce solids buildup which will cover plants and kill the VFS.

Infiltration and plant uptake sequester the P, meaning post-treatment is often not

necessary. However, it is difficult to recover P-rich fertilizer from the filter strip. VFSs

work best when the flow is shallow and uniform rather than in channels or gulley. The

required size of VFS for large operations may be prohibitive. VFSs are typically not

designed to meet strict nutrient management limits for nutrient removal. In some

instances, the P levels at the outlet are above approved discharge levels (Canadian

Pork Council, 2005).

26

2.6.4 Effectiveness

VFSs are up to 90% effective at trapping sediment (70% on average) and up to 50%

effective at trapping soluble nutrients. Variations occur due to site-specific conditions

such as vegetation, slope, soil type, size and geometry of filter strip, and influent solids

concentration. Because the majority of the phosphorous is adsorbed to solid particles,

total P removal is directly related to soils removal efficiencies (Green and Haney, no

date).

In Worner and Lorimor (no date), P removal rates ranged from 12% to 97%, averaging

68.7% for VFS. Other research has shown that 80% reductions of total Kjeldahl nitrogen

and P are achievable as a function of the ratio of VFS area to the feedlot drainage area

(VFS:DA). [% P reduction = 23.433 ln (VFS:DA) + 65.635]

2.6.5 Economics

The costs of establishing a VFS is dependent on the type of VFS system (channelized or

overland flow), type of vegetation used, size of strip required, etc. One must also

consider cost of land lost to VFS. Some maintenance (harvesting of biomass) is

required. Effective VFSs require a good stand of dense vegetation, uniform flow

conditions, minimal soil disturbances (animal and vehicle traffic should be minimized)

and proper harvesting of vegetation (Woerner and Lorimor, no date). Harvesting should

be done periodically to not only remove nutrient accumulation, but to help in maintaining

a healthy stand.

The Canadian Pork Council (2005) stated that establishing a VFS has a similar cost to

establishing a pasture. Depending on the size of animal, the number of acres/head/year

ranges from 0.01 to 0.06. Data from Featherston (2004 in: Canadian Pork Council, 2005)

show that the capital cost of a VFS can range from $3,000 for 140 head of swine to

$22,000 for 2,000 head of swine. The annual operating cost ranged from $270 to

$4,500.


Koelsch et al. (2006) identified 40 field and plot studies looking at the effectiveness of

VFS at reducing nutrient loading in the US. The authors also mentioned a model that

performs site-specific modeling using daily weather inputs to estimate the performance

of site-specific feedlots and VFS designs. Model verification was in progress at the time

of paper publication.

The Ohio State University Extension also published a document outlining the application,

installation, and maintenance of vegetative filter strips.

27

References



#0-9696896-8-3.

Green, C.H., R. Haney. No date. Filter Strips. Phosphorus Best Management Practices

Factsheet. Developed by SERA-17, Minimizing Phosphorus Losses from Agriculture.

Available online http://sera17.ext.vt.edu/ Accessed: April 20, 2010.

Koelsch, R., J. Lorimor, K. Mankin. 2006. Vegetative treatment systems for open lot

runoff: review of literature. In: Animal Agriculture and the Environment: National Center for

Manure and Animal Waste Management White Papers. J.M. Rice, D.F. Caldwell, F.J.

Humenik, eds. St. Joseph, MI: ASABE Pub. Number 913C0306. Pp. 575-608.






28

2.7 Constructed Wetlands


Similar to vegetative filter strips, constructed wetlands (CW) are designed to slow the

flowrate of contaminated runoff. However, unlike vegetated filter strips, constructed

wetlands are designed to retain the effluent for a period of time to stabilize and uptake

nutrients (similar to lagoons). Constructed wetlands provide an opportunity for reduction

of pollutants in runoff through two primary mechanisms: (1) sedimentation, typically

occurring within the first few meters of a treatment area, and (2) infiltration of runoff into

the soil profile. The soil system also provides a physical structure and biological

environment for treatment of pollutants including filtration (e.g. restricting movement of

most protozoa and bacteria), immobilization (e.g. soil cations immobilizing ammonium),

aerobic processes (e.g. conversion of organic compounds to water and carbon dioxide),

and anaerobic process (e.g. conversion of nitrates to nitrogen gas). The CW also allows

the recycling of nutrients by plants (Fajardo et al., 2001 in: Koelsch, 2006). Constructed

wetlands are considered a low-cost alternative to the land application of feedlot waste.

There are two types of CWs: free water surface and submerged flow. Free water

systems are more appropriate for open feedlot runoff due to the larger flow volumes

required.

Pretreatment for VFS or construction wetlands can include an infiltration area. Soil

infiltration occurs by loading/ponding a soil medium with runoff and allowing the liquid to

“soak into” the soil. As the waste infiltrates the soil, phosphorus interacts and becomes

attached to the soil particles in the profile. Field drainage tiles may be used to intercept

the filtrate and carry it to a secondary form of treatment such as a constructed wetland or

a VFS.


Constructed wetlands are suitable for any liquid manure, but are mainly used to treat

open lot beef feedlot runoff.


Constructed wetlands require proper design for effective treatment. They are good

for smaller applications, but may not meet P removal requirement (inherently not

good at P removal). Constructed wetlands are also highly sensitive to changes in

influent characteristics and flowrate.

They are generally not as effective in cold climates and require large areas.

Cannot stand alone to treat feedlot runoff because of high ammonia concentrations

29

typically found in the runoff, which is toxic to wetland plants.

Plants can include rushes, cattails, knotgrass, smartweed, spiked bulrush, reeds,

sedge, etc.

Some form of preliminary treatment is needed to keep the organic loading within

design limits (Woerner and Lormior, no date).

Constructed wetland effluent may require some P reduction before it can be

discharged into a surface watercourse (Canadian Pork Council, 2005).

Periodic pump out and solids removal is required.

2.7.4 Effectiveness

Proper design of constructed wetlands may result in the area exceeding the size of the

feedlot. Percent removal of P was 88% with a low loading rate (1 kg/ha-day) while

removal was 30% for 11 kg/ha-day loading. Solids removal ranges from 30% to 99%

(74.7% average) while P removal ranges from 28% to 88% (70.2% average) (Woerner

and Lorimor, no date).

Another reference (Hawkins, no date) quoted a 42% removal efficiency. Components

such as settling + VFS + infiltration + CW can individually remove 34%, 68.7%, 78%,

and 50% of incoming P, respectively. For example, an open beef feedlot using settling,

followed by VFS following by wetland can potentially remove up to 90% of total P.

Recent studies showed an 89% reduction in P from swine manure runoff and 78%

reduction in P using open beef feedlot runoff using an infiltration area.

The total P concentration reduction efficiency for all cold climate sites reviewed in Pries

et al. (no date) ranged from 25% to 77% (dairy and swine) with the higher efficiencies

due to better pre-treatment (solids removal).

2.7.5 Economics

Depending on the type of wetlands (free water surface and subsurface flow),

establishment can cost $20,000/acre to $145,000/acre (Hawkins, no date).

The suggested size for wetlands is 1 acre/65 lb BOD per day (1,000 m2/7kg of BOD per

day) (Rieck et al., 1993 in: Canadian Pork Council, 2005). Assuming the preprocessing

(lagoon storage) removes 50% of BOD, a single acre of land is large enough for 300

finishing pigs. Costs for a free water surface CW are estimated to be between $32,000

and $45,000/acre in Phillips et al. (2001 in: Canadian Pork Council, 2005) and will

depend partially on availability of equipment and clay for the lining of the wetland.

Constructed wetlands should be nearly maintenance free (Canadian Pork Council,

2005). On occasion, partial pump out for application to land may be performed to lower

water levels. Solids that are removed need to be stored and disposed.

30

Pries et al. (no date) noted that the main economic disadvantage of wetland treatment is

the cost of land and the possibility of taking farmland out of production. However, for a

farm operation that has land available for this treatment technology, particularly land that

is poor quality or that is already wetland, land costs are less of an issue. Operating costs

are generally very low and depend on the extent of monitoring data collection, exotic

plant control, burrowing animal activity, and water management. Area requirements for

wetland treating high-strength agricultural wastewater ranges from 0.01 ha to 0.64 ha

per 100 AU (1 AU = 1,000 kg live weight), for an average of 0.13 ha/100 AU.

Approximate construction costs ranged from $26/AU (for 340 AU) to $540/AU (for 100

AU). The average capital cost was $129/AU. These costs represent a variety of wetland

designs and, in many cases, unknown contaminant loadings. They do not necessarily

reflect optimum treatment efficiencies. Other design considerations include:

pretreatment, aeration, dilution, and climate.


Constructed wetlands have been applied to open lot runoff. Their design and

management is challenged by the intermittent flow from open lots. Koelsch et al. (2006)

suggest that seasonal open lots used for winter livestock housing and be emptied into

the wetlands only during the summer.

Pries et al. (no date) discussed the design of constructed wetland systems for cold

climates (Canada specifically). In most cases, contaminated washwater and/or

stormwater was collected during the winter in holding ponds, which provided primary

treatment and then it is discharged to the wetland during the growing season. Important

design considerations in cold climate areas include: requirements for water storage

during winter months, inflow and outflow structures that withstand prolonged periods with

below freezing temperatures, and extra freeboard for year-round systems. Surface flow

wetlands treating municipal wastewater were maintained in Listowel Ontario in the early

80’s. They were continuously operated throughout the winter by controlling the

insulation. Water levels were raised at freezeup, and a layer of ice was allowed to form.

The water level was then lowered to create an insulating air gap between the water and

ice. The stems of the dense stand of emergent cattails served as supports to keep the

ice layer elevated. The standing dead cattails trapped snow and added an insulating

snow blanket. Wetlands to treat agricultural waste are successful in Nova Scotia and

Ontario. Wetland construction costs are determined by the cumulative cost of land,

earthwork, planting, design, monitoring, and maintenance. Capital costs in cold climate

regions were reported to be between $4,000 and $50,000 for wetlands ranging in size

from 0.01 ha to 1 ha. The range in costs reflects variables such as liner installation,

removal and replacement of topsoil, and specialized monitoring equipment. A

31

subsurface flow system at a Quebec zoo (subsurface flow requires less area) is a 0.7 ha

vertical flow system constructed at a cost of $500,000.

Scholz et al. (2007) reviewed constructed wetland design for phosphate removal in

farmyard runoff in UK by analyzing the performance of 13 full-scale wetlands operating

in the UK. They concluded that the critical design factor for P reduction was that the size

must be at least 1.3 times the farmyard area and the width to length ratio must be less

than 1:2.2. Relatively high reductions of molybdate reactive phosphate (MRP) were

observed (from 20 down to 1 mg/l).

32

References



#0-9696896-8-3.

Hawkins, J. No date. Constructed Treatment Wetlands. Phosphorus Best Management

Practices Factsheet. Developed by SERA-17, Minimizing Phosphorus Losses from

Agriculture. Available online http://sera17.ext.vt.edu/ Accessed: April 20, 2010.

Koelsch, R., J. Lorimor, K. Mankin. 2006. Vegetative treatment systems for open lot

runoff: review of literature. In: Animal Agriculture and the Environment: National Center for

Manure and Animal Waste Management White Papers. J.M. Rice, D.F. Caldwell, F.J.

Humenik, eds. St. Joseph, MI: ASABE Pub. Number 913C0306. Pp. 575-608.

Pries, J.H., R.E. Borer, R.A. Clarke, R.L. Knight. No date. Performance and design

considerations of treatment wetland systems for livestock wastewater management in cold

climate regions in southern Canada and the northern United States. Available online:

http://gis.lrs.uoguelph.ca/agrienvarchives/bioenergy/download/Regina_CSE_paper.pdf

Accessed: April 20, 2010. 26 pp.

Scholz, M., A.J. Sadowski, R. Harrington, P. Carroll. 2007. Integrated constructed

wetlands assessment and design for phosphate removal. Biosystems Engineering 97:415-

423.





http://gis.lrs.uoguelph.ca/agrienvarchives/bioenergy/download/Regina_CSE_paper.pdf


33

2.8 Precision Manure Application


Precision manure application is not a manure treatment method, but proper manure

application can help reduce P contamination. This involves proper timing, rates,

uniformity of distribution, and application methods of manure. Because the N:P ratio of

most manures is lower than that required by the soil-crop system, applying manure at a

rate sufficient to satisfy nitrogen requirements results in over application of P. Due to P

accumulation concerns, manure application rates are (or will be) based on P level in

manure, not N content. This will require producers to supplement manure with

commercial N fertilizer to meet N requirements. This may also require manure to be

applied at low rates. Many commercial systems (particularly for solid manure) cannot

accurately apply manure at low rates. Precision application also includes adoption of

variable rate application to target nutrient deficient areas in the field, as discussed in the

MLMMI demonstration study by Dick et al. (2010). Finally, placing the manure beneath

the soil surface reduces the risk of runoff/transport losses of P. Injection of liquid manure

is very common in the prairies (drag line systems and low disturbance coulter injection),

but subsurface application of solid manure is not common.


Precision manure application can be applied to any manure that is land applied, and is

particularly effective for those that are applied often (daily scrape/haul).


Since most P and organic N are contained in the solids portion of the lagoon, good

agitation during pumpout is essential to ensure even application of the nutrients in the

field.

Selecting the proper application rate involves soil and manure tests and knowledge of

the P requirements of the crop to be planted.

Soil testing for P management involves mechanisms of P transport (rather than simply

soil nutrient levels). Hence, producers are encouraged to use a P Indexing Site

Assessment Tool rather than soil test P alone (Sharpley et al., no date).

Injection or incorporation of manure may reduce risk of P runoff but can increase risk

of soil erosion, excessive compaction and require higher energy inputs.

2.8.4 Effectiveness

If only the amount of P that will be used by plants/soil is applied, the risk of P runoff and

contamination can be eliminated. However, the land area required to meet P

34

requirements may be prohibitively large in areas where livestock operations are

concentrated. Injection of slurry can decrease runoff total P concentration by 82%

(Daverede et al., 2004).

To maximize the efficiency of precision application systems, real-time, “on-the-go”

measurement of manure nutrient content is required. This would allow application rates

(or tractor speeds) to be adjusted accordingly. Past studies by PDK Projects in MB

looked at the use of near infrared spectroscopy for rapid analysis of available N and P in

hog manure (MLMMI 98-01-15 and 99-01-25 and 00-02-03). Useful calibrations were

found for the rapid measurement of NH4-N and total P contents (among other

components).

2.8.5 Economics

Proper management of application rates (using existing application equipment) involves

only the cost of soil and manure sampling and analysis. Electronically mapping the field

in the variable rate application demonstrations study (Dick et al., 2010) cost

approximately $8/acre. Other costs associated with precision application could include

testing and calibration of existing equipment to ensure target application rates are met.

In some cases, the purchase of new equipment may be required.


Several studies have shown that subsurface application (injection of slurry or

incorporation of solid manure) reduces the P runoff risk (Maguire and McGrath, no date;

Daverede et al., 2004; Sharpley et al., 2001; etc.) The variable rate demonstration study

in MB (Dick et al., 2010 MLMMI 2008-01-30) used global positioning systems to map

fields and prescribe variable rates based on soil testing and satellite imagery. The

manure was applied using drag hose systems and control of the application rate was

achieved by changing the tractor speed. Therefore, human error was involved. Also,

actual nutrient application rates could not be determined until manure analysis results

were received from the lab. Participating farmers had generally positive feedback about

the system, except many indicated the cost ($8/acre) was too high.

Lague et al. (2006) reported on a precision manure applicator that improved uniformity of

distribution and control of application rate for solid and semisolid manure. The coefficient

of variation of transverse uniformity was less than 10% using the prototype. Traditional

spreaders with horizontal or vertical beaters/spinners typically have poor uniformity

(coefficient of variation>100%). The prototype was also modified to allow subsurface

application of solid manure in a single pass. Although the subsurface application

resulted in significant soil disturbance and required high energy inputs, the risk of

surface runoff of P was reduced.

36

References

Daverede, I.C., A.N. Kravchenko, R.G. Hoeft, E.D. Nafziger, D.G. Bullock, J.J. Warren,

L.C. Gonzini. 2004. Phosphorus runoff from incorporated and surface-applied liquid swine

manure and phosphorus fertilizer. Journal of Environmental Quality 33:1535-1544.

Dick, S., C. Loewen, W. Barnes. 2010. Applying manure to defined management zones

using precision farming techniques. Demonstration Project MLMMI 2008-01-30.

Lague, C., J. Agnew, H. Landry, M. Roberge, C. Iskra. 2006. Development of a precision

applicator for solid and semi-solid manure. Applied Engineering in Agriculture 22(3):345-

350.

Maguire, R., J. McGrath. No date. Manure injection in no-till and pasture systems.

Available online:

http://www.mawaterquality.org/publications/pubs/Manure%20Injection%20in%20No-

Till%20System.pdf. Date accessed: May 26, 2010. 5 pp.

Sharpley, A.N., P. Kleinman, R. McDowell. 2001. Innovative management of agricultural

phosphorus to protect soil and water resources. Commun. Soil Sci. Plant Anal.

32(7&8):1071-1100.

http://www.mawaterquality.org/publications/pubs/Manure%20Injection%20in%20No-Till%20System.pdf

http://www.mawaterquality.org/publications/pubs/Manure%20Injection%20in%20No-Till%20System.pdf

37

2.9 Other Technologies

Other manure treatment technologies include drying (for dilute systems), granulation (for

poultry litter), pasteurization, and pelleting. None of these processes affect the P content

of the manure but they reduce volume, make the material easier (and cost effective) to

handle and help improve uniformity of distribution after application. Thermo-chemical

processes such as combustion, gasification, and pyrolysis are primarily used as energy

recovery methods. The P is retained in the by-products, usually ash and tar. The volume

of material to be treated is greatly reduced, but capital costs of these units are very high.

Pyrolysis and gasification are considered to be too undeveloped for common application

at this time (Buckley, 2009).

In the literature, recommended treatments for chicken manure included incineration,

gasification, drying, and composting. Incineration of most manure results in high ash

contents with high P concentrations. Incineration results in concentration of P2O5 by

thermal removal of water and organic matter. The quality of phosphate in ash residues

was disappointing in one study but there is hope to use ash as feed phosphate or

fertilizer (Adviesbureau, 1998). Moller et al. (2007) also discussed the P content in ash

after manure (pig, cattle, and fermented manure) incineration in Denmark. Incineration of

the solid fraction from a centrifuge with straw produced a bottom ash and fly ash

containing high levels of P which can be used as a fertilizer without much risk of heavy

metal loading. However, incineration seemingly converts 80% of P to apatite, which is

unavailable for plants. Thus the value as a P fertilizer is low, while the immobilization of

P may be beneficial for down-stream ecosystems. Heavy metals (Cu, Ni and some Cd)

are present in the bottom ash as well. Greaves et al. (1999) noted that a large portion of

poultry litter in the UK is incinerated for electrical generation and the ash is sold as P

fertilizer.

Mulbry and Wilkie (2001) suggested an alternative to land application of manure. They

suggested growing algae which has exceedingly high growth and nutrient uptake rates.

This method also provides biomass for energy and or feed supplement. They

investigated algal turf scrubber technology to remove nitrogen, P, and chemical oxygen

demand from raw and AD dairy manure. Most work with algae production for nutrient

removal from manure is at the lab scale. Algae growth for nutrient removal is only

efficient in temperate climates. Pizarro et al. (2006) reported on the same technology

using dairy manure in Maryland. A hypothetical economic analysis identified that if a

market for manure grown algal biomass existed, it would be economically feasible to

generate algal biomass as a nutrient recovery technique.

Innoventor’s SME (swine manure to bio-oil) system was designed to reduce odours and

generate a marketable product from swine manure. During the process, hog waste is

pumped from the pits under the barn and fed to the system where a specially designed

38

boost pump elevates the pressure and temperature of the slurry. The slurry is held under

pressure and temperature in a reactor where the slurry turns into bio-oil. The black water

is separated and the bio-oil is dried upon leaving the reactor. The entire process takes

an hour. The bio-oil is currently being used as a binder for asphalt. The Missouri

Department of Transportation is currently using the bio-oil and monitoring its

performance throughout several seasons. Innoventor claims that the black water could

be used as a nutrient source and that the SME system would eliminate the need for

storage lagoons. Although the majority of the nutrients would be lost in the bio-oil,

revenue from the product could be used to offset the cost of purchasing commercial

fertilizer. The reactor is currently processing at a commercial scale on a 5,000 head hog

farm. (Source: Manure Manager Magazine, May/June 2010).

39

References




36 pp.

Buckley, K.E. 2009. Overview of solid manure treatment options. Manitoba Livestock

Manure Management Initiative (MLMMI). Achieving Manure Phosphorus Balance in

Manitoba. Workshop: November 30-December 1, Winnipeg, Manitoba.



Moller, H.B., H.S. Jensen, L. Tobiasen, M.N. Hansen. 2007. Heavy metal and phosphorus

content of fractions from manure treatment and incineration. Environmental Technology

28:1403-1418.

Mulbry, W.W., A.C. Wilkie. 2001. Growth of benthic freshwater algae on dairy manures.

Journal of Applied Phycology 13:301-306.

Pizarro, C., W. Mulbry, D. Blersch, P. Kangas. 2006. An economic assessment of algal

turf scrubber technology for treatment of dairy manure effluent. Ecological Engineering

26:321-327.



40

3. Description of Multistage Treatment Technologies and

Canadian Implementations

Several references discussed the application of operating several of the treatment

systems described above (as well as a few not described above) in series to achieve

more efficient nutrient removal. Many multiple-stage treatment systems include

anaerobic digestion as a method to recover energy from the waste and generate a

revenue stream. Certain technologies that target individual nutrients (such as P

compounds) can hinder the performance of other technologies that target other nutrients

(such as nitrogen compounds). Therefore, multiple stage systems need to be carefully

designed. On the other hand, additional benefits to these advanced treatment

technologies include greenhouse gas emission reduction, odour emission reduction, and

better recovery and utilization of nutrients.

3.1 Multiple Stage Treatment Systems

Sheff (2004) discussed the implementation of a FAN separator (screw press) along with

chemical augmentation to control nutrient content of dairy effluent (both flush and scrape

systems). The systems have been successfully pilot tested in full scale in Europe and

the US. Separation is achieved in several stages including a screw press and centrifugal

classifier sorter. Tertiary treatment is performed with a dissolved air floatation unit.

These units achieved 90% P removal/inactivation.

Vanotti et al. (2009) discussed their system to treat swine waste in North Carolina. The

system used solids separation, nitrification/denitrification and phosphorus

removal/disinfection (no lagoon) and was demonstrated at full-scale on a 5,145 head

swine farm during three production cycles. P removal efficiency was 95%. The

economics of the second generation system (which required fewer chemicals and had a

slightly lower P removal efficiency) was $7.13 per finished pig (35% more costly than

anaerobic lagoon spray field technology). This system was considered to be energy-

efficient, environmentally friendly, and profitable and was awarded an Agricultural

Research Service technology transfer award.

Karakashev et al. (2008) also presented a multiple stage treatment system approach for

use with pig manure in Denmark. The final scheme included thermophilic AD, sequential

separation by decanter centrifuge, post digestion in upflow anaerobic sludge blanket

(UASB), partial oxidation, and oxygen-limited autotrophic nitrification/denitrification

(OLAND). P removal by precipitation as struvite from pig manure was also tested.

Results showed that microfiltration was unsuitable for pig manure treatment due to

plugging issues. Struvite production negatively affected further processing and was

therefore not included in final process. In their final scheme (all processes except

41

struvite precipitation), P reduction occurs after centrifugation and partial oxidation steps.

The main PO4 reduction resulted from AD and centrifugation steps. The combination

resulted in a reduction of the P content by 81% from pig manure. AD and microfiltration

were done at full-scale while precipitation, UASB, partial oxidation and OLAND were

done at lab-scale. Full-scale AD with decanter centrifuge achieved 62% reduction in P

content while producing 1.3x106 m3 biogas/year on 19,000 m3 substrate/year. However,

the effluent after centrifuge still had high P content and did not meet European Union

environmental legislation as source of fertilizer for agricultural use.

Flotats et al. (2009) presented a “whole farm treatment” approach including AD,

acidification, evaporation/drying, and pelletization for manure (pig, cattle and poultry)

treatment in Spain. Their multistage farm scale system achieved 94% reduction of

nutrients (including P). The P originally in the manure was recovered in the pelletized

dried product. These multistage, capital intensive systems are obviously only feasible for

large, centralized facilities that handle large quantities of manure per day.

The company, Bioscan, has designed and tested a complete treatment system for pig

manure which included (1) coarse solids (>1 mm) filtration, (2) AD coupled to ultra

filtration for biomass retention, (3) ammonia and carbonate stripping, and (4) reverse

osmosis (3.2 MPa, 35-40⁰ C) of the bottom part of the stripper for P and K concentration.

The system was installed on a farm in Denmark and reportedly reduced P content to

1.2 mg/l. No data on long-term performance, cleaning strategies, and costs were

available (Masse et al., 2007).

A wastewater treatment technology that removes P from liquid manure with minimal

chemical addition while producing a valuable by-product is covered in Vanotti et al. 2003

(in: Szogi et al., 2006). This technology includes nitrification of wastewater to oxidize

ammonia, reduce carbonate buffers, and subsequent increase of the pH of nitrified

wastewater by adding calcium hydroxide to precipitate P. The final product is a calcium

phosphate rich sludge that has the potential to be reused as fertilizer, but its high

moisture content makes transportation difficult. Therefore, dewatering is necessary to

economically transport the P product off the farm. Sludge dewatering techniques that

concentrate P may include settling of solids followed by decantation, centrifugation, or

filtration procedures to remove the liquid fraction. Vanotti et al. (2003) also claimed that,

using their biological treatment system (nitrification plus lime treatment), the amount of P

removed (and consequently the N:P ratio of the effluent) could be adjusted to match

specific crop needs. The final product is calcium phosphate.

Shepherd et al. (2009) discussed the testing of a pilot-scale (80 to 115 l/min) air sparged

tank reactor in combination with a hydrocyclone on two swine manure slurries for

struvite based P removal and recovery. The system provided a 92% reduction of

dissolved reactive P. The system was less effective at recovering total P from the slurry

42

which was attributed to the hydrocylone’s inability to provide effective struvite separation

as operated. In a case study of a typical Iowa deep-pit swine facility (10,000 head/year),

the annual cost of struvite based P removal using this system was approximately

$8.88/finished pig or $0.035/l of treated slurry, which was higher than their profit margin,

therefore, not economically viable.

Most of the European manure management technologies included complex, multiple

stage treatment systems like the one described by Karakashev et al. (2008). Generally,

these systems are designed for centralized treatment facilities where one unit treats the

manure from several farms. The high cost of transportation and large distance between

farms in MB mean that centralized processing facilities are not feasible. Also, the

European systems are designed for total nutrient and odour management and often

include anaerobic digestion for the generation of biogas. Incentives for green energy

production in Europe make the high capital cost of these systems manageable.

However, these incentives do not exist in Manitoba. Therefore, systems that have been

successfully implemented in Europe are not likely to be sustainable in the Canadian

prairies.

43

References

Flotats, X., A. Bonmati, B. Fernandez, A. Magri. 2009. Manure treatment technologies:

On-farm versus centralized strategies. NE Spain as case study. Bioresource Technology

100:5519-5526.

Karakashev, D., J.E. Schmidt, I. Angelidaki. 2008. Innovative process scheme for removal

of organic matter, phosphorus and nitrogen from pig manure. Water Research 42:4083-

4090.

Masse, D.I., F. Croteau, L. Masse. 2007. The fate of crop nutrients during digestion of

swine manure in psychrophilic anaerobic sequencing batch reactors. Bioresource


Sheff, B.B. 2004. A system for manure treatment and nutrient control of dairy waste.

ASABE Annual International Meeting. Paper No.: 04-4169.

Shepherd, T.A. R.T. Burns, D.R. Raman, L.B. Moody, K.J. Stalder. 2009. Performance of

a pilot-scale air sparged continuous flow reactor and hydrocyclone for struvite precipitation

and removal from liquid swine manure. Applied Engineering in Agriculture 25(2):257-267.

Szogi, A.A., M.B. Vanotti, P.G. Hunt. 2006. Dewatering of phosphorus extracted from

liquid swine waste. Bioresource Technology 97:183-190.

Vanotti, M.B., A.A. Szogi, P.G. Hunt. 2003. Extraction of soluble phosphorus from swine

wastewater. Transactions of ASABE 46(6):1665-1674.

Vanotti, M.B., A.A. Szogi, P.D. Millner, J.H. Loughrin. 2009. Development of a second-

generation environmentally superior technology for treatment of swine manure in the USA.

Bioresource Technology 100:5406-5416.

44

3.2 Canadian Implementations

The MLMMI Phosphorus Workshop highlighted specific technologies that have been

implemented in Canada. For example, the Institut de recherché et de developpement en

agroenvironnement (IRDA) has tested their mobile centrifuge in Quebec and Manitoba.

Solids removal was between 45% to 50% while P removal was 58% to 63% (mostly in

solids). Other manure treatment technologies in use in Quebec include belt separation

(85% to 95% P removal), aerobic digestion (currently bankrupt) and anaerobic digestion

(two in operation, one under construction).

The BIOSOR biofiltration process is currently in use on two Quebec farms. This process

involves passing the manure through a decanter/digester with the aim of neutralizing the

variations in load, reducing the concentration of suspended solids, and stabilizing the

decanted sludge by anaerobic digestion. This first stage can reduce P load by 71%. The

solids from this separation stage can be composted. The second stage involves passing

the liquid effluent through an aerobic organic bed (peat moss and wood chips) which can

reportedly remove 80% of the P in the effluent. System capacities range from 17 m3/day

on a pig farm to 500 m3/day at a poultry slaughterhouse. The output of the process can

be applied to fields or outputted to a river. Operational issues related to ammonia toxicity

were identified. The technology reportedly requires little maintenance (a few hours per

week by a non-specialized employee). The technology is considered a complete manure

treatment process as it removes or stabilizes nutrients, pathogens, and odours. The total

capital cost was estimated to be $425,000 ($15/1000 lb produced).

An example of a manure treatment technology in Manitoba includes the Deerboine

Colony advanced manure treatment plant by Osorno Enterprises Inc. Processes include

an aerated lift station, separation, coagulation/flocculation, biological treatment

(activated sludge), composting of solids, and discharge of liquids into a pond. The

process is currently considered full scale and can handle 50 m3/day of liquid manure.

The system reportedly produces treated wastewater that is suitable for reuse or

discharge, a hygienic compost material and exhaust gas that has undergone biological

cleanup. Osorno Enterprises Inc. stated that the individual steps in the treatment

process are well-established, but they have not been applied to date in Canada for the

treatment of manure. The system reportedly removes approximately 90% of phosphate

although it is designed to be a complete nutrient removal system. Information on ease of

operation and nutrient removal efficiency is currently being collected.

A similar system (Livestock Water Recycling (LWR)) is being assessed for treatment of

swine manure by Hytek Ltd. The LWR system (based out of Calgary, AB) reportedly

eliminates the need for a manure storage lagoon while outputting clean water, dry solids

and liquid fertilizer. The process steps include bulk solids removal, fine solids removal

45

(chemically aided), conditioning to form nutrient salts, and filtration to collect salts and

particles. During a case study trial in Manitoba (operated for 4 months in 2008), 750 m3

of liquid manure was treated at 30 l/min. The system removed 100% of phosphorus. The

system can treat 64,000 m3/year at a commercial installation at a farrow to finish swine

operation in central AB. LWR noted that challenges to implementation in MB include

winter conditions and economic factors. The total capital investment is between

$400,000 and $600,000 while operating costs include $0.27/m3 for chemical, $0.24/m3

for maintenance, $0.23/m3 for power (total $0.74/m3).

A slightly less complex system is being developed by Pig Manure Treatment Ltd. (out of

Halifax, NS). The first step involves natural degradation in a lagoon and step two is an

in-line flocculation separation system that screens solids and augers the solids to a

screw press and then on to a storage area. The solids are composted while the liquid

portion is further treated in a lagoon. The system is fully automated and can handle 21

m3 of slurry per hour. The treated liquid fraction (after storage in lagoon) reportedly had

86% less phosphate than the raw material. Capital costs were estimated to be $250,000

while operating costs were $1.10/m3. Total annual costs were estimated to be

approximately half that of present separation technology. One installation is currently in

use in MB and has been successfully operated for over three years. The main difference

between this system and the LWR and Osorno systems is the lack of treatment of the

liquid fraction.

Another system is one proposed by Samson Engineering Inc. which involves separation

and digestion of liquid swine manure. Their vibrating screening system (V-SEP)

reportedly has fewer plugging/fouling issues than traditional screening systems and is

particularly effective when used in combination with anaerobic digestion. Phosphorus

removal efficiency results are currently from lab scale studies. Samson Engineering Inc.

is working with Riverbend Colony in Manitoba to implement the system.

Other projects include the farmyard runoff control cooperative with producers to

investigate the feasibility of practices such as collection basins in Deerwood, Oakbank,

and Dauphin in Manitoba. The recovery of liquid pig manure phosphorus as struvite is

being tested by the National Centre for Livestock and the Environment. Testing using

digested manure is at the bench scale, while testing with manure from uncovered

earthen manure storages is at a pilot scale. Finally, there are numerous examples of

successful anaerobic digestion (biogas) facilities in Ontario, B.C., and Alberta that are

processing manure. These systems are primarily used for biogas (energy) recovery and

are not designed to target P removal.

Anaerobic digestion is not very common in Canada due to the energy required to

maintain mesophilic and thermophilic temperatures in the reactor. However, a low

temperature (phychrophilic) digester was developed by AAFC and commercialized by

46

Bio-Terre. Two above-ground installations are operating in Quebec, and one lagoon

system is operational in Manitoba. The design is a two-stage system which allows for a

longer solids retention time to facilitate breakdown, but liquid retention time is not as long

to increase capacity. The smallest Bio-Terre installation cost $700,000 (Manure

Manager Magazine, June/July, 2010).

Brandon based Home Farms Technologies Inc. produced a multistage solid/liquid

separator that was in use at Green Acres Colony in Wawanesa, Manitoba which

represented the only full-scale manure separation system that could be confirmed in MB

in 2007. The system involved screening and flocculation to achieve solids removal

(Hofer, 2007 in: Cicek, 2007). The system was being monitored by AAFC Brandon and

was achieving 62% to 70% solids removal. The solids were being composted with

deadstock in crude piles and windrows but they are planning on constructing a large-

scale rotating drum for the co-composting process.

The Puratone-IRDA mobile centrifugation system consists of an Asserva-300 decanter

centrifuge mounted inside a trailer (Cicek, 2007). The mobile centrifuge is removing up

to 70% of the P and the solids are approximately 35% dry matter. Mobile separators may

present significant challenges associated with logistics (scheduling, maintenance), and

biosecurity (Cicek, 2007). Puratone in Manitoba was also actively investigating a solids

separation technique based on filtration, centrifugation, and settling using chemical

amendments.

Finally, the FAN screw press separator was evaluated for the treatment of liquid hog

manure by Van Kleeck (1994) in British Columbia. In this system, the first stage of

separation is achieved by gravity, leaving a concentrated slurry on the screen (different

screen sizes are available for different applications). The concentrated slurry is then

pushed by a screw auger towards the mouthpiece of the separator. The pressure

created by the build-up of solids causes further liquid to be squeezed out of the matrix

prior to it being pushed out of the separator. The separator is equipped with a vibration

system to increase the flow rate and improve squeezing action when separating difficult

slurries. However, the FAN separator was shown to not function well with dilute hog

slurries (<3% solids) but did work fine if thin slurries were pre-concentrated before

separation, either by inclined screen or by gravity settling. With pre-treatment, the

system was able to remove 79% of the solids and 9% of the dissolved P. The author did

not measure the reduction of total (solid bound) P, however. There is at least one

example of a successful implementation of the FAN separator system at Elite Stock

Farms in Outlook, SK (1,200 sow breeder/multiplier barn). The system is used to

separate the solids when pumping out of the primary cell. The system was noted to be

relatively slow and although it was reliable, it required daily monitoring. The cost to

purchase a FAN separator was in the range of $30,000 Cdn in 1993.

47

References

Cicek, N. 2007. Assessment of Potential Hog Manure Processing Strategies in

Manitoba. In: A Report on Current Knowledge of Key Environmental Issues Related to

Hog Production in Manitoba. D. Flaten, K. Wittenburg, Q. Zhang, Clean Environment

Commission. October, 2007.

Elite Stock Farms, Outlook, SK. Personal Communication, 24/6/10.

MLMMI Achieving Manure Phosphorus Balance in MB, workshop 2009, Nov 30-Dec 1,

Greenwood Inn and Suites, Winnipeg, MB.

Van Kleeck, R. 1994. FAN Engineering Manure Separator. Waste Management

Factsheet. Resource Management Branch, Ministry of Agriculture, Food and Fisheries.

Abbotsford, BC.

48

4. Evaluation of Treatment Technologies

Developing technologies for P removal or recovery from manures will help enable

farmers to cope with new manure handling legislation while simultaneously helping to

protect the environment from cultural eutrophication and conserve P resources for future

generations. To determine which technology is most suitable for the types of farms and

environmental conditions in Manitoba, an evaluation matrix was developed. The goal of

the matrix was to include weighted factors based on their importance to livestock

operations in Manitoba.

The critical success factor for the operation of the manure treatment installations is often

not of technical but of economic nature. To be cost effective in comparison with the

disposal of untreated manure, the costs must be balanced out by the sale or the lower

disposal costs of the manure products. As market prospects and disposal costs for

manure and its products differ from case to case, no generally preferred manure

treatment technique can be pointed out from this study, as local market circumstances

must be taken into account.

Solid-liquid separation and biological treatment processes such as composting,

anaerobic digestion and aeration are important unit operations that will provide

fundamental solutions to environmental problems created by concentrated waste

streams from large-scale livestock operations. Due to the farm environments in which

these technologies need to be located, these technologies need to be cost-effective,

reliable and robust. This means that the technology must be able to handle variable

content (particle sizes, nutrient content, temperature, organic loading, etc.) The

technologies also must be proven reliable and demonstrated at full scale. Results from

lab scale jar tests are not sufficient with which to make decisions.

Additionally, selected technologies must be appropriate for the size of farm. Larger farms

(Colonies) provide potential for economy-of-scale and more efficient use of technologies.

However, small farms must also comply with environmental regulations and are looking

for solutions to the P concentration issue. Many of the multi-stage, complex technologies

are too costly for the average farmer. In certain areas of MB, it may be feasible to initiate

a centralized manure treatment system where one unit handles the manure from multiple

farms within an economical transport distance (10-20 km). However, this method would

require farmers to completely change the way they handle their manure. Simple, cost

effective ways to remove P from the liquid portion and reduce the volume of the P rich

solid portion would allow farmers to economically land apply their effluent while

transporting the solid portion to P deficient areas.

Based on these factors, the evaluation matrix was designed to rank manure handling

49

technologies and identify gaps in the existing experience and research. The

technologies were ranked based on the following factors, from highest weighted to

lowest weighted:

1. Efficiency at reducing/removing P (30%)

2. Capital cost (15%)

3. Operating cost (10%)

4. Flexibility of implementation (5%)

5. Ability to accommodate manure types and species (5%)

6. Ability to handle fluctuations in manure composition (5%)

7. Ability to handle fluctuations in manure temperature and ambient conditions (5%)

8. Number of successful implementations employed in industry (5%)

9. Energy efficiency (5%)

10. Scalability of technology (5%)

11. Complexity of operation (5%)

12. Ability to produce value added by-product (5%)

Except for #5, all technologies were evaluated based on their ability to handle liquid

manure (specifically swine manure). The efficiency score was based on the reported %

reduction of P that could be achieved by the technology. Calculations showed that a

75% reduction in P content is required to maintain current manure application rates

(approximately 3500 gal/acre) on the same land base. This would result in applying the

amount of P that would be taken up by traditional crops (wheat, canola, etc.) Higher

reductions would result in a lower P application (at 3500 gal/acre), resulting in a net

uptake of P by crops. Alternatively, high P reductions (>92%) would allow application at

higher rates to the same land base while meeting P application rate guidelines.

Individual technologies (mechanical separation, chemically enhanced separation,

composting, constructed wetlands, etc.) were evaluated separately from the multi-stage

and commercial implementations (Geotube, the Vanotti System (2009), BIOSOR

biofiltration, SME system, etc.) The full evaluation, including a description of the scoring

levels for each factor, is included in the spreadsheet in Appendix I.

Based on those factors and weightings, the highest scoring individual technology was

mechanical separation. There are numerous examples of commercial systems (notably

the FAN screw press separator and the IRDA centrifuge) and they are robust and proven

to efficiently separate solids for manure with a dry matter content >3%. For more dilute

slurries, a settling and/or chemical pre-treatment and decanting routine may be required

to improve the efficiency of subsequent mechanical separation. Since the majority of P is

bound in the solid fraction, separating the solid portion effectively lowers the P content

50

(and raises the N:P ratio) of the effluent. The solids portion can be further processed to

reduce volume and transported to P deficient areas.

Chemically enhanced separation ranked second among the individual technologies.

Although coagulant and flocculant addition is usually intended to enhance mechanical

separation, it may be used on its own to effectively separate solids and isolate manure

P. Results from current research can be used to identify specific organic salts and

polymers and the required loading rate. Since some of the chemical amendments can be

costly, chemical addition had a relatively high operating cost.

Ranked third among the technologies was gravity settling (lagoons). These systems are

low cost, but when operated with a “business as usual” approach, they are not efficient

at sequestering P. Typically, approximately 50% of the solids settle in a manure storage

or lagoons, but these solids are usually resuspended in the slurry before application. By

managing lagoons and settling basins differently, with the aim to reduce P in the applied

slurry, these systems can be an effective treatment option. This benefit could be further

enhanced if the effluent is applied using precision manure application techniques.

Vegetative filter strips and constructed wetlands were ranked next. These systems are

designed to handle a specific manure composition and their use for swine manure and

during a Canadian winter is minimal. Biological treatment, composting and anaerobic

digestion ranked the lowest. Biological treatment systems have high capital costs and

are sensitive to microbial populations, meaning they are generally not robust systems.

Their main advantage is total nutrient management, so they are generally very complex.

The main benefits of anaerobic digestion and composting are the production of biogas

and volume reduction, respectively, which were not considered as factors in the

evaluation matrix. As stand-alone technologies, digestion and composting would not be

good solutions for the handling of manure P. However, they are valuable additions to

any manure management system. In particular, composting the solid fraction from

separation systems can reduce the volume of the P-rich by-product, making it more

economical to transport to P-deficient areas. Anaerobic digestion can generate energy

rich biogas which, when converted to heat and electricity, can help generate revenue for

the farm.

For the ranking of the commercial and multi-stage technologies, some of the scores for

each factor were considered “soft scores” due to the lack of information available for

operating costs, energy efficiency, etc. These soft scores were based on the

descriptions available in literature and reasonable inferences and assumptions. The

highest scoring commercial technologies were the Sheff, LWR, and PMT systems.

Although the Sheff system has only been commercially applied to the treatment of dairy

manure, the process (enhanced FAN separation and additional effluent treatment) is

applicable to swine manure treatment. The application of the LWR system for Manitoba

51

livestock production is in the process of being tested. The PMT system (essentially

enhanced settling in a lagoon with separation and composting of the settled solids) is

also currently in use in Manitoba. Next was the BIOSOR biofiltration system. Although

there are full-scale systems in operation at two different farms in Quebec, the system’s

robustness and reliability is not well established. The Geotube membrane (filtration

dewatering) system ranked next. The main benefit of the Geotube system is its efficiency

at removing (separating) P and its low cost. In addition, commercial units are available

for testing. However, this system has never been tested in the Canadian climate and

there are some concerns about plugging and fouling of the membrane. The next highest

ranking system was the swine manure to bio-oil system. While the technology

completely eliminates the need to worry about P balance in manure, the nutrient value is

lost almost entirely as the by-product is used for road construction materials. Also, the

exact mechanism of manure processing was not available in literature, making it difficult

to assess the technology’s robustness and reliability. The Vanotti system ranked next,

followed by the more theoretical Karakashev and Shepherd systems. These systems are

difficult to differentiate from each other due to the limited information available.

Based on an overall assessment of the available technologies, the individual

technologies that hold the most promise for dealing with the manure P issue in Manitoba

is a combination of chemically enhanced and mechanical separation. Ideally, these

would be used in conjunction with existing storage systems. However, some

modifications to existing systems may be required. For example, in order to concentrate

the solids of dilute slurries to improve the efficiency of mechanical separation (such as

the FAN separator), a two stage storage could be adopted. The solids content in the first

cell of a two stage system would be high enough to efficiently operate a FAN separator.

If ~80% of the solids (and undissolved P) remained in the first cell and ~80% of those

solids were removed by the separator, then an overall solids reduction of 64% could be

realized. The P-rich solids removed from the lagoon can be composted to reduce the

volume and transported to P-deficient areas for land application. The land application of

the stored effluent can be optimized by employing precision application strategies.

Satellite mapping and on-the-go nutrient sensors would optimize precision application

systems, but even proper machine calibration and user education could help minimize

the risk of over-application.

In terms of commercial systems for larger operations, all have their advantages and

disadvantages. More installations are required to make a better assessment as to which

ones will reliably work for MB livestock operations. Based on the information available in

literature, the LWR and PMT systems hold the most promise if a high reduction of P is

required. However, issues with their operation in the MB climate are unknown and an

accurate long-term operating cost estimate is required for implementations in Manitoba.

The BIOSOR biofiltration system ranked highly, but the efficiency of the aerobic biofilter

is dependent on highly sensitive microbial communities, making the system sensitive to

52

manure composition. The Sheff system (FAN separator with chemical augmentation and

dissolved air floatation unit) has only been tested on dairy manure in the US and Europe

to date. The swine manure to bio-oil technology is interesting, but the loss of nutrient

value of manure would be costly. Properly designed and operated, these multi-stage

systems offer comprehensive management of manure nutrients, including P, but their

capital cost is prohibitive for smaller scale operations. Specific components of these

systems (chemicals, rates, equipment for handling solids, etc.) may be used to enhance

the ability to manage manure P in existing systems such as lagoons.

53

5. Recommendations and Research Gaps

In terms of commercially available manure treatment technologies to help remove and

treat manure P, the following are recommended for further testing:

FAN separator with pre-treatment (similar to Sheff system) (approximately

$50,000 capital plus operating and modification costs)

Pig Manure Treatment (capital cost of $250,000, operating cost of $1.10/m3)

Livestock Waste Recycling (capital cost of $400,000 and operating cost of

$0.75/m3)

The following are recommended with reservations:

BIOSOR biofiltration (capital cost of $400,000 plus operating costs)

Geotube dewatering membrane (capital cost of $15,000 for a 10,000 head barn

plus $2.64/m3 for chemical)

Vanotti system (separation with P disinfection) (total cost of $7.13 per finished

pig)

While there has been a lot of research and attention on specific technologies to deal with

manure P, we are still lacking information and methods in certain areas. Specifically, the

feasibility of technologies like constructed wetlands and biomass composting in the

Canadian climate is unclear. Additionally, the feasibility and efficacy of these systems on

a smaller scale (<1,000 animal units) needs to be assessed. Improving the self-cleaning

capabilities of screens is another potential research area for filtration methods.

Cost-effective and reliable chemical application methods for flocculation need to be

developed and integrated into the chemically enhanced separation systems. Research

on chemical amendments needs to be in the area of basic research to determine why a

given chemical or biological additive works, not just whether it does. Only through

understanding the basic mechanisms of the interactions that occur will truly effective

additives ever be developed. Optimal handling and treatment of manure may also

require a complete change in the way manure management systems are configured.

On the other hand, to further develop the use of existing technology like gravity settling

systems and precision application, specific research is required. This includes

investigating chemical additives or other methods to enhance settling in lagoons or

storage tanks. Since the majority of the P will be bound to the solid particles, the solids

should be removed and treated separately from the effluent. Currently, solids are not

easily removed from storage lagoons. The feasibility of removing and treating the

accumulated solids needs to be investigated. Treatment options for the solid portion

include composting. There are several farm-scale operations that include some form of

composting, but research on emerging methods and technologies like the Ag-Bag

composting system is required. Also, the feasibility of biomass composting (with fly

larvae) in the Canadian climate should be investigated. Biomass composting has the

54

potential to reduce the volume and P content of the solid portion of manure.

To optimize the benefits of precision manure application, several developments are

required. Firstly, a soil and manure testing regime needs to be established to help

farmers define prescribed rates for their fields. Ideally, on-the-go nutrient sensors would

be perfected so the nutrient content of the manure could be continually monitored during

application. Also, annual machine calibration is required to ensure that target application

rates are met. There is also a need to develop solid manure spreaders that apply the

manure uniformly across the width of spread and applicators (both liquid and solid) that

accurately apply low rates. Finally, as with any new technology or practice, extension

and education programs will be required to help the producers learn how to efficiently

manage their systems.

55

6. Manure Treatment Technologies Test Protocol

Development

Manufacturers and developers of technologies that treat or convert manure into other

forms typically claim expected performance levels and costs of the technologies. Some

mature technologies are supported by data from multiple installations, whereas new

technologies may have minimal documented evidence to support their performance

claims. For producers, determining whether these claims are accurate and legitimate

can be a daunting task, especially considering that Manitoba has a unique climate and

soil type compared to many locations in North America. Having unbiased test and

evaluation data available from a third party with firsthand experience with the

technologies in question is of tremendous value when considering the implementation of

such technologies. Since there are many forms of technologies, it is imperative that a

standard approach be followed in any evaluation work to ensure consistence of results

and allow for unbiased comparison.

The Association of State Energy Research and Technology Transfer Institutions

(ASERTTI), the U.S. Environmental Protection Agency AgSTAR Program, and the U.S.

Department of Agriculture Rural Development Program jointly supported the

development of a standard protocol for quantifying and reporting the performance of

anaerobic digestion systems for livestock manures. This approach allows a consistent

data to be collected on numerous types and sizes of digesters and allows for an

independent evaluation of the systems. This type of evaluation provides livestock

operations, considering the implementation of an anaerobic digester system, access to

unbiased performance and economic data and allows for an informed decision before a

large capital expenditure. Evaluating a single system reduces the risk for subsequent

installations.

Based on the information studied during this literature review, the following items are

deemed essential for determining the effectiveness of any manure treatment system:

1. Evaluations conducted on commercial scale systems operating at steady state and

tested with manure having a consistent nutrient and physical property profile.

2. A minimum duration for evaluation includes the winter and the transition during

spring and fall, if the treatment systems rely on biological activity.

3. Quantification of changes in the manure nutrient and physical property profile from

influent and all effluent streams from the treatment system. Essential parameters

include TKN, TP, Ortho P, S, TS as a minimum.

4. Quantification of pathogen reduction claims based on actual microbial counts of

samples taken from the treatment system influent and effluent streams.

5. An economic evaluation based on “as built” costs of the system once it is in a steady

state of operation (fully commissioned).

56

6. Critical evaluation of required daily/weekly/monthly labour requirements for

operational and maintenance activities and estimation of operator skill level required.

7. Quantification of energy inputs and operating costs other than labour that is required

for the manure treatment system operation.

8. Determination of mass balance of the system to provide overall operating efficiency

of the system.

9. Develop a standardized unit of measure for all parameters monitored during the

evaluation process and report performance measurements on a standard volumetric

or mass basis per unit of time to provide a relative indication of operational efficiency.

10. A record of livestock operations during the evaluation period.

57

Appendix I

Evaluation Matrix

1

Solid

liq

uid

sep

arat

ion

(gr

avit

y se

ttlin

g)

Solid

liq

uid

sep

arat

ion

(m

ech

anic

al s

ep

arat

ion

)

Ch

emic

ally

en

han

ced

sep

arat

ion

Bio

logi

cal t

reat

men

t

Co

mp

ost

ing

An

aero

bic

Dig

esti

on

(B

ioTe

rre)

VFS

/Co

nst

ruct

ed W

etla

nd

s

Pre

cisi

on

Man

ure

Ap

plic

atio

n

Van

ott

i Sys

tem

Kar

akas

hev

sys

tem

Shep

her

d s

yste

m

BIO

SOR

bio

filt

rati

on

Oso

rno

En

terp

rise

s

LWR

/PM

T Sy

stem

SME

(Sw

ine

man

ure

to

bio

-oil)

Shef

f Sy

sem

Ch

emic

ally

en

han

ced

sep

arat

ion

(G

eo

tub

e)

Item Description Score Scoring Method Weighting

1

Number of successful implementations currently employed in industry

1 Only application is at research stage with no commercial implementation

5%

3 3 2 2 3 3 3 2 2 1 1 2 2 3 2 3 2

2 Single installation at commercial scale

for evaluation purposes 0.15 0.15 0.1 0.1 0.15 0.15 0.15 0.1 0 0.1 0.05 0.05 0.1 0.1 0.15 0.1 0.15 0.1

3 Multiple installations at commercial scale with service history available

2

Flexibility for implementation into existing animal housing/manure storage systems

1 Requires new animal housing or

manure storage system

5%

3 2 2 1 3 1 3 3 2 2 2 2 2 2 3 2 2

2 Can be incorporated into existing barn

systems but extensive rework is required to existing infastructure

0.15 0.1 0.1 0.05 0.15 0.05 0.15 0.15 0 0.1 0.1 0.1 0.1 0.1 0.1 0.15 0.1 0.1

3 Can be incorporated into existing

systems with minimum rework required to existing infastructure

3

ability to accommodate various animal manure types species or solid/liquid

1 Specific to single animal species

(poultry, hog, dairy, etc.) or manure type (solid, liquid, slurry)

5%

2 2 2 3 1 2 2 3 2 2 2 2 2 2 2 1 1

2

Able to accommodate manure from multiple animal species (poultry, hog,

dairy, etc.) OR manure type (solid, liquid, slurry)

0.1 0.1 0.1 0.15 0.05 0.1 0.1 0.15 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.05 0.05

3

Able to accommodate manure from multiple animal species (poultry, hog, dairy, etc.) AND manure type (solid,

liquid, slurry)

2

4

ability to handle fluctuations in manure composition (rubustness)

1

Limited to specific manure nutrient and physical property profile (manure produced from an animal at a specific

growth stage with a specific feed ration)

5%

3 2 2 1 2 1 2 2 2 2 2 2 2 2 3 2 1

2

Able to accommodate minor differences in re nutrient and physical

property profile (manure produced from animal at a multiple growth

stages or single animal growth stage with multiple feed rations)

0.15 0.1 0.1 0.05 0.1 0.05 0.1 0.1 0 0.1 0.1 0.1 0.1 0.1 0.1 0.15 0.1 0.05

3

Able to accommodate minor differences in re nutrient and physical

property profile (manure produced from animal at a multiple growth stages and multiple feed rations)

5

ability to handle fluctuations in manure temperature and ambient temperatures

1 Limited to specific season only

temperatures

5%

3 3 2 2 2 2 1 3 2 2 2 2 2 2 2 2 1

2 Able to accommodate multiple

seasons 0.15 0.15 0.1 0.1 0.1 0.1 0.05 0.15 0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.05

3 Able to accommodate a Manitoba

winter/summer (-30 to +30C)

6 estimated capital costs

1 > 1M in capital required

15%

3 2 2 1 2 1 2 3 2 1 2 3 2 2 2 2 3

2 between $500,000 to $1M

0.45 0.3 0.3 0.15 0.3 0.15 0.3 0.45 0 0.3 0.15 0.3 0.45 0.3 0.3 0.3 0.3 0.45

3 <$500,000

7 operating costs

1 10x cost of existing manure handling

system

10%

3 2 2 1 2 2 3 2 2 2 2 3 2 2 2 2 2

2 5x cost of existing manure handling

system 0.3 0.2 0.2 0.1 0.2 0.2 0.3 0.2 0 0.2 0.2 0.2 0.3 0.2 0.2 0.2 0.2 0.2

3 1-3x cost of existing manure handling

system

8 System energy efficiency

1 High energy input required

5%

3 1 2 2 2 2 3 2 2 1 2 2 2 2 1 2 2

2 Medium energy input required

0.15 0.05 0.1 0.1 0.1 0.1 0.15 0.1 0 0.1 0.05 0.1 0.1 0.1 0.1 0.05 0.1 0.1

3 Low energy input needed for

operation

9 Ability to produce value added by-product

1 No additional value added by product

potential

5%

1 2 2 3 3 3 1 3 3 3 2 2 2 2 1 2 1

2 Future potential for value added by

product 0.05 0.1 0.1 0.15 0.15 0.15 0.05 0.15 0 0.15 0.15 0.1 0.1 0.1 0.1 0.05 0.1 0.05

3 Emmediate potential for value added

by product

10 scalability for large/small producers

1

System not readily scalable between farm sizes or adaptable to

increasing/decreasing animal populations and requires mimum animal population to be effective

5%

3 2 2 3 1 2 3 3 1 1 2 2 2 2 2 2 1

2

System is scalable or modular to allow for variations in animal populations

but requires mimum animal population to be effective

0.15 0.1 0.1 0.15 0.05 0.1 0.15 0.15 0 0.05 0.05 0.1 0.1 0.1 0.1 0.1 0.1 0.05

3

11 complexity of operation

1 Requires trained and dedicated staff to

operate and maintain

5%

3 2 2 1 3 2 2 2 1 1 2 2 2 2 1 1 2

2 Requires trained staff to operate and

maintain but does not need to be dedicated to operation

0.15 0.1 0.1 0.05 0.15 0.1 0.1 0.1 0 0.05 0.05 0.1 0.1 0.1 0.1 0.05 0.05 0.1

3 A guy off of the street could operate

and maintain the system

12 ability to increase N:P ratio

1 Does not help improve the P balance

in manure (<10% reduction in P)

30%

1 3 3 3 1 1 2 0 3 2 1 2 1 2 3 3 3

2 Marginally helps to improve the P

balance in manure (~50% reduction in P)

0.3 0.9 0.9 0.9 0.3 0.3 0.6 0 0 0.9 0.6 0.3 0.6 0.3 0.6 0.9 0.9 0.9

3 Eliminates need to worry about P

balance in manure (>85% reduction in P)

Total Weighted

Score 2.25 2.35 2.3 2.05 1.8 1.55 2.2 1.8 0 2.25 1.7 1.65 2.25 1.7 2.05 2.25 2.25 2.2

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