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Module 8: Nutrient Management8.1: Introduction to macro- & micronutrients8.2: Nitrogen8.3: Phosphorous8.4: Potassium and other nutrients8.5: Solid & liquid nutrients produced by AD8.6: Environmental hazards & the case for nutrient separation8.7: Phosphorous separation strategies8.8: Nitrogen separation strategies8.9: Salt removal & clean water technologies8.10: Soil nutrients & soil health8.11: Creation & implementation of cNMP8.12: Data collection, reporting & complianceThis curriculum is adapted from: eXtension Course 3: AD, University of

Wisconsin

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8.1: Macro- & micronutrients

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Nutrients

Nutrients are elements, ions or molecules found in soil that are vital for thegrowth and development of plants.

• Plant nutrients are then vital to the growth and development of herbivores, omnivores and, indirectly, carnivores.

Long ago, scientists like Justus von Leibig & Carl Sprengel understood that crop yields are constrained by a number of factors, like nutrients. They developed the Law of the Minimum:

“Every field contains a maximum of one or more and a minimum of

one or more nutrients. With this minimum, be it lime, potash,phosphoric acid, megnesia, or any other nutrient, the yields

stand in direct relation. It is this factor that governs and controls…

yields.”

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Nutrients in = nutrients out…

… since AD really removes only a significant amount of carbon.

However, AD does change the form of some nutrients.

• A mixture of nutrients is embodied (bound up) in the bacteria that drive the anaerobic process & are present in effluent.

• Nitrogen in effluent is largely in the form of ammonia.• Ammonia may be lost as a gas.• The ratio of ammonia gas to ammonium ion (present in salts) is

pH dependent. As pH drops the proportion of gaseous ammonia increases.

• Phosphorous takes the form of orthophosphate (P2O5) and is both:

• Soluble and present in liquid effluent; and• Has a tendency to bind to small particles and partition into solids.

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AD produces macro- & micronutrients

Plant macronutrients are present in significant quantities in plant tissues: 0.2 – 4.0% of dry weight• C (carbon from air), H (hydrogen) & O (oxygen) (from both air & water)• Primary macronutrients: N (nitrogen), P (phosphorous), K (potassium)• Secondary macronutrients: Ca (calcium), S (sulfur), Mg (magnesium)

Plant micronutrients (aka trace elements) are present at lower concentrations,typically measured in parts per million (ppm), ranging from 5 – 200 ppm.• Boron (B)• Chlorine (Cl)• Managanese (Mn)• Iron (Fe)• Zinc (Zn)• Copper (Cu)• Molybdenum (Mo)• Nickel (Ni)

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AD produces macro- & micronutrients

macr

onutr

ients

hydrogen H 60,000,000 6%

oxygen O 30,000,000 45%

carbon C 30,000,000 45%

nitrogen N 1,000,000 1.5%

potassium K 400,000 1%

phosphorous P 30,000 0.2%

calcium Ca 200,000 0.5%

magnesium Mg 100,000 0.2%

sulfur S 30,000 0.2%

chloride Cl 3,000 100 ppm

iron Fe 2,000 100 ppm

boron B 2,000 20 ppm

manganese Mn 1,000 50 ppm

zinc Zn 300 20 ppm

copper Cu 100 6 ppm

molybdendum Mo 1 0.1 ppm

nickel Ni 0.1 0.01 ppm

mic

ronutr

ients

Havlin (2005)

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8.2: Nitrogen

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NitrogenNitrogen is the most frequently deficient nutrient in non-legume crops.

• N-fixing legumes can supply their own nitrogen.

While N2 gas makes up 78% of our atmosphere, N is not available to

plants unless it is converted into a bioavailable form of N by:

• Microbes living symbiotically on legume roots;

• Free-living (non-symbiotic) soil microbes;

• Atmospheric electrical discharges (lightning);

• Manufacture of synthetic N fertilizer.

Plants use nitrogen to make proteins required for growth & development, and to make chlorophyll, the molecule plants use to convert sunlight into energy.

Plants with adequate nitrogen have vigorous vegetative growth and a dark green color.• Excess nitrogen can cause a lack of structure (succulence) and

lodging. Havlin (2005)

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Nitrogen deficiencyA lack of nitrogen in plants causes leaves to have a yellow appearance.

The yellow color (chlorosis) results from a lack of proteins in chloroplasts in older leaves.• Occurs first on lower (thererfore older) leaves.• The effect starts at leaf tips and moves inward toward the stem.• Affected leaves then turn brown & die.

Havlin (2005)

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Nitrogen cycle

Darby (2009)

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NitrogenNitrogen makes up 50% of the dry matter of plant material and is a essential part of all amino acids and proteins.

Forms of N:

• Plants cannot use the N2 gas that makes up 78% of our atmosphere.

• Most N is taken up from soil as soluble nitrate, NO3-1.

• In acidic environments, soluble ammonium (NH4+1) predominates.

• Creation of bioavailable N is a biological process called nitrification/denitrification, driven by soil microbes.

Crops that require more N?• N is often the limiting factor for growth of many agricultural crops.• Corn requires high levels of N

Nitrogen deficiency slows and stunts plant growth and causes chlorosis.• Stems and the underside of leaves & petioles appear purple because

of accumlated antrocyanin. N is required to form chlorophyll.

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Forms of N

Havlin (2005) Fig 4-1

Plants take up N in two water soluble forms:

1. Nitrate (NO3-1) – taken up at high rates

2. Ammonium (NH4+1) – taken up at neutral pH (uptake supressed by

acid pH)

Nitrate is taken up by plant roots and converted to ammonium and then to amino acids & proteins.• Conversion requires energy and the reductive cofactor NADH.

Ammonium can be used directly (without conversion) and is the plant’s preferred form of N.

• However, high levels of NH4+1 can retard growth and uptake of

potassium.• So, ammonium application levels are more critical.

Some crops prefer one form of bioavailable N over the other.

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Forms of soil N

Havlin (2005)

Soil N is higher close to the top of soil. Average N concentrations are:• < 0.02% in subsoil• > 2.5% in organic soil

In the top 1 foot of US soil, N concentrations range from 0.03 – 0.40%• 95% is organic N• 5% is inorganic

Inorganic soil N includes ammonium (NH4+1), nitrite (NO2

-1), nitrate (NO3-

1), nitrous oxide (N2O), nitric oxide (NO), and element N2. [=

bioavailable]• Only 2 – 5% of soil N

Organic soil N includes: • proteins• amino acids (20 – 40%)• amino sugars (5 – 10%)• other complex, N-containing biomolecules (< 1%)

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Forms of N created by AD

Havlin (2005) Fig 4-36

AD converts most N into ammonia / ammonium. The ration of these two forms is determined by the pH of the AD slurry or effluent.• Note that below pH 8, ammonium predominates.

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Mineralization of soil N = bio-activation

Havlin (2005)

In order to supply sufficient bioavailable soil N, organic N must be mineralized: converted to ammonium through two reactions:

1. aminization2. ammonification

protein

NH2

|R – C – COOH | H

R – NH2

NH2

|C = O |NH2

CO2 energyH2O

bacteriafungi

+ + + +

amino acids amines urea

1

2 R – NH2 + H2O NH3 + R - OH energy+

NH4+1 OH-1+

Ammonium is then:1. Converted to nitrite & nitrate via nitrification2. Absorbed by plants3. Used by microbes to decompose organics

4. Fixed to N2 & back to atmosphere5. Converted to ammonia & volatilized

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Immobilization of soil N = storage

Havlin (2005)

Immobilization: the reverse of mineralization; conversion of inorganic N to organic N for long-term storage• Immobilization occurs when soil OM has low [N].• Immobilized N is used to help the population of microbes grow.

Soil C:N ratios determine whether N is mineralized or immobilized.• C:N > 20:1 N is initially immobilized• C:N < 20:1 N is initially mineralized

N content of soil and soil amendments also predicts whether added N is mineralized or immobilized.• If N > 2% under aerobic conditions, mineralization occurs.

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C:N ratios control flow of N

Havlin (2005)

XXX C:N ratiosoil microbes 8:1

soil organic matter 10:1

sweet clover 12:1

rotted manure 20:1

green rye 36:1

corn / sorghum residue 60:1

grain straw 80:1

timothy 80:1

tar & asphalt 95:1

coal lipids / shale oil 125:1

wood 200-1000:1

crude oil 400:1

sawdust 400:1m

iner

aliza

tion

imm

obili

zatio

n

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Sources of nitrogenN can be supplied in either organic or inorganic forms.

Organic forms of NBefore 1850, all nitrogen was provided by animal manure or legume N.Today, these sources account for only 35% of agricultural N use.

1. Manure200 million tons (dry weight) of manure are produced in the US annually.• 60% from grazing animals is not collected.• 40% from confined animals is collected and used.• 16 million acres of cropland (8%) is fertilized with manure.• N content depends on 1) feed, 2) handling, 3) soil quality.

2. Legumes

3. Sewage Sludge

Havlin (2005)

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Manure nitrogen

Havlin (2005)

ton/yrper

1000 lbfeces

%urine

%

aminoacid

%urea

%NH4

+1

%

uricacid

%other

%

poultry 4.5 25 75 27 4 8 61 1

sheep 6.0 50 50 21 34 1.5 - 43

horse 8.0 60 40 24 25 1 - 49

beef 8.5 50 50 20 35 0.5 - 44

dairy 12 60 40 23 28 0.5 - 49

swine 16 33 67 27 51 0.5 - 22

Typical manure N:• 1 – 6% total N• 50 - 75% organic N

• 25 – 50% ammonium (NH4+1)

The organic N must be mineralized before it is bioavailable to plants.

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Manure nitrogenMost manure N is organic and must be mineralized before plants can use it.

• Unstable: urea & uric acid

• Readily mineralized to NH4+1

• There can be significant loss if ammonium is converted to

ammonia (NH3)

• 15 – 40% of total manure N can be lost as ammonia is volatilized.

• Losses can be as high as 60 – 90% if manure is stored in a lagoon.

• Stable organic N is slowly mineralized after it is land-applied• 50% in 1st year; 25% in 2nd year; 12.5% in 3rd year

Rates of mineralization Nmin = N0 (1 – e-kt)

Havlin (2005)

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Inorganic nitrogenSynthetic forms of N are now the most important sources of N for plants.Over the last 30 years, global N consumption has increased from 22 to 85 metric tonnes per year.

In the US, 70% of total N used is:

• Anhydrous NH3

• Urea• N solutions

Anhydrous NH3 is created by the Haber-Bosch process, using enormous

amounts of fossil fuel. This ammonia is the basis of most synthetic N fertilizers.

Havlin (2005)

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Manure nitrogen

Havlin (2005) Fig 4-40

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8.3: Phosphorous

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PhosphorousPhosphorous is an essential component of many biomolecules, including: • phospholipids used in building cell membranes• nucleic acids (DNA & RNA) used to encode & store genetic

information; and• ATP, biology’s energy carrier.

In soil, levels of P range from 0.005 – 0.15%.• However, the bioavailability of soil P depends on its chemical form.

Forms of P:• Phosphourous is bioavailable when in soluble forms & depending on

pH:

• phosphate = H2PO4-1

• Orthophosphate = HPO4-2

• However, most phosphate is unavailable because it is locked up in inorganic phosphate precipitates; solids like rock.

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Phosphorous for fruitingAdequate P is associated with increased growth of roots and is required for plant reproduction & production of seeds & fruits. P increases the rate of maturation of crops.

Phosphorous deficiency causes:• intense green coloration of leaves

• Turning to blue-green or silver-green in extreme cases;• And a purple tinge in corn & other grasses; and

• Stunting.

Plants’ ability to mobilize and use P depends on temperature. So in unusually cool weather, crops can show signs of deficiency even when soil concentrations of P are adequate.• Application of extra (starter) P can help.

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Phosphorous cyclePlants use soluble or solution phosphorous and their ability to access P depends on the concentration of that soluble P. Stores of soluble P are buffered by the processes of mineralization and immobilization.

Havlin (2005) Fig 5-1

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Phosphorous pricing

Cordell (2009)

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Peak phosphorous?

Global Phosphorous Research Initiative; Dery & Anderson, 2007

Most of us have heard of peak oil, but we have already reached peak phosphorous: within 50 – 130 years the world will not have sufficient mined phosphorous to support the agricultural needs of the human population.• As the human population surges, this timeline may shrink.

The geography of phosphorous mining also poses challenges. Ninety (90) percent of global phosphorous reserves are found in five countries:

1. Morocco 2. China 3.South Africa 4. Jordan 5. US

Phosphorous prices will continue to rise as demand escalates in the face of a finite supply of mined phosphorous.

However, if we stop wasting phosphorous and learn to capture and recycle nutrients in food, agricultural and human waste, we can ease the impact of peak phosphorous.

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Phosphorous in manure

Inorganic P is bound to particulates that are formed from Ca-P and Mg-P.• Ca is present at a high Ca:P molar ratio of 1.6 – 2.3 in dairy diets.

• Amounts of dissolved or soluble P are small:• 12% in dairy manure• 7% in AD effluent

• P-bearing particles are small (20 – 600 μM).

Solids separation uses screensof 3,000 μM, so does not catch most particulate P.

Gerritse & Vriesema (1984); Zhang (2010); Ghapuis-Lardy (2004);Gungor & Karthikeyan (2005a,b, 2008)

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8.4: Potassium & other nutrients

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What about potassium?

Darby (2009)

Potassium (K) is important for plant growth, reproduction & winter survival of perennial plants.• K is a cofactor for plant enzyme system.• K is easily lost from soils at a cost to farmers.• Over-application of K adversely affects herd health.

A small portion of soil K is bioavailable to plants, and that ‘exchangeable’, or solution, K is detected by soil testing. K bound to clay soils slowly enters the soil solution pool as it exchanges off.

Potassium deficiencies cause lower leaves to appear burned, spotted & yellow.• Soils with low cation exchange capacities aren’t able to retain

potassium.

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Potassium cycle

Darby (2009)

K is soluble & thus leachable from soil with low CEC.K is readily taken up by plants or……bound to soil or SOM, more as pH increases.

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Potassium use by crops

Darby (2009)

Potassium is taken up by all crops in large amounts and accumulates in the leaves & stems. Highest levels are therefore required by forage crops like silage and hay.

Potassium deficiency causes lower leaves to look burned, spotted with areas of yellow.• Soils with low CEC are most susceptible as they can’t hold K reserves.• Alfalfa requires large amounts of potassium to resist winter injury.• Hay does as well, but has deeper root systems and can extract K more

easily.

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Secondary macronutrients & micronutrients

Darby (2009)

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Sources & resources (1)This curriculum is a modification of the wonderful:• eXtension Course 3: AD, University of Wisconsinhttp://fyi.uwex.edu/biotrainingcenter/online-modules/series-three-anaerobic-digestion/

Additional sources & resources:Ahn, C.H., Park, H.D., Park, J.K. (2007) Enahanced biological phosphorous removal

performance and microbial population changes at high organic loading rates, Journal of Environmental Engineering, 133(10): 962 – 969.

AlgeEvolve (2013) Nutrient recovery through algae, The 7th AgSTAR National Conference, Indianapolis, Indiana

Battistoni, P., Paci, B., Fatone, F., Pavan, P. (2006) Phosphorous removal from anaerobic supernatants: start-up and steady-state conditions of a fluidized bed reactor full-scale plant. Industrial Engineering Chemistry Research, 45: 663-9.

Bishop, C.P. and Shumway, C.R. (2009) The economics of dairy anaerobic digestion with co-product marketing, Review of Agricultural Economics, 31(3): 394-410.

Bowers, K.E. & Westerman, P.W. (2005) Performance of cone-shaped fluidized bed struvite crystallizers in removing phosphorous from wastewater, Transactions of the ASAE, 48: 1227-34.

Chapuis-Lardy, L., Fiorini, J. Toth, J. Dou, Z. (2004) Phosphorous concentration and solubility in dairy feces: variability and affecting factors, Journal of Dairy Science, 87(12): 4334 – 4341.

Churchouse, S. and Wildgoose, D. (1999) Membrane bioreactors progress from the laboratory to full-scale use. Membrane Technology, 1999(111), 4 – 8.

Darby, H (2009) Digging in: a nutrient management course for farmers, UVM ExtensionDery, P. & Anderson, B. (2007) Peak phosphorous, Energy Bulletin, 13 April 2007

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Sources & resources (2)DVO (2013) Personal communicationEekert, M.H.A., van, Weijma, J., Verdoes, N., Buisonje, F.E., de, Reitsma, B.A.H., Bulk, J. van

Strichting Toegepast Onderzoek Waterbeheer (STOWA)PFrear, C., Liao, W., Ewing, T., Chen, S. (2011) Evaluation of co-digestion at a commercial

dairy anaerobic digester, Clean Air, Soil, Water, 39(7) 679-704.Frear, C., Wang, Z., Li, C., Chen, S. (2011) Biogas potential and microbial population

distributions in flushed dairy manure and implications on anaerobic digester technology, Journal of Chemical Technology & Biotechnology, 86: 145 – 152.

Gerritse, R.G. & Vriesema, R. (1984) Phosphate distribution in animal waste slurries, Journal of Agricultural Sciences, 102(1): 159-161.

Global Phosphorous Research InitiativeGungor, K. & Karthikeyan, K.G. (2005) Influence of anaerobic digestion on dairy manure

phosphorous extractability, Transactions in the ASAE, 48(4): 1497-1507.Gungor, K. & Karthikeyan, K.G. (2005) Probable phosphorous solid states and their stability

in anaerobically digested dairy manure, Transactions of the ASAE, 48(4): 1509-1520.Gungor, K. & Karthikeyan, K.G. (2008) Phosphorous forms and extractability in diary

manure: a case study for Wisconsin on-farm anaerobic digesters. Bioresource Technology, 99(2): 424-436.

Halpern, D. (2013) Low cost nutrient recovery for improved project profitabiilty, 2nd Annual Anaerobic Digestion and Biogas Conference 2013, San Francisco, CA.

Havlin, J.L., Beaton, J.D., Tisdale, S.L., Nelson, W.L. (2005) Soil fertility and fertilizers: an introduction to nutrient management, 7/e, Pearson, Saddle River NJ

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Sources & resources (3)ICUSD (2013) National market value for anaerobic digestion products. Report to Innovation

Center for US Dairy, AugustJeong, Y.K & Hwang, S.J. (2005) Optimum doses of Mg and P salts for precipitating ammonia

into struvite crystals in aerobic composting, Bioresource Technology, 96: 1-6.Jiang, A., Zhang, T., Chen, S., Zhao, Q, Li, X., Frear, C. (2013) Evaluation of an integrated

ammonia stripping, recovery, and biogas scrubbing system for use with anaerobically digested dairy manure, Biosystems Engineering, accepted.

Kemira (2011) Case study: mechanical/chemical liquid solid separation of anaerobic digestate. The Sixth AgSTAR National Conference, Boise, Idaho

Le Corre, K.S., Valsami-Jones, E., Hobbs, P., Jefferson, B., Parsons, S.A. (2007) Agglomeration of struvite crystals, Water Research 41: 419-425.

Lei, X.H., Sugiura, N., Feng, C.P., Maekawa, T. (2007) Pretreatment of anaerobic digestion effluent with ammonia stripping and biogas purification, Journal of Hazardous Materials, 145(3): 391 – 397.

Liao, P.H., Chen, A., Lo, K.V. (2005) Removal of nitrogen from swine manure wastewaters by ammonia stripping, Bioresource Technology, 54(1): 17 – 20.

Ma, J., Kennedy, N. Yorgey, G., Frear, C. (2013) Review of emerging nutrient recovery technologies for farm-based anaerobic digesters and other renewable energy systems, Prepared for Innovation Center for US Dairy, Washington State University

MHF (2013) Multiform harvest. Personal communication

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Sources & resources (4)Mino, T., Van Loosdrecht, M.C.M., Heijnen, J.J. (1998) Microbiology and biochemistry of the

enhanced biological phosphate removal process, Water Research, 32(11): 3193 – 3207.Mulder, M. (2000) Basic principles of membrane technology, Kluwer Academic Publishers,

Dordrecht, The Netherlands.Pedros, P.B., Simon, M.M., Brown, S.H. (2013) US Patent No. 9,398,855, USPTOPeter-Varbanets, M., Zurbrugg, C., Swartz, C., Pronk, W. (2009) Decentralized systems for

potable water and the potential of membrane technology, Water Research, 43(2): 245 – 265.

Sialve, B., Bernet, N., Bernard, O. (2009) Anaerobic digestion of microalgae as a necessary step to make microalgal biodiesel sustainable. Biotechnology Advances, 27: 409 – 416.

Spindler, H., Bauermeister, U., Meier, T., Teske, M. (2011) US Patent No. 7,887,615, USPTOSutton, M.A., Reis, S., Bahl, K.B. (2009) Reactive nitrogen in agroecosystems: integration

with greenhouse gas interactions, Agriculture, Ecosystems & Environment, 133(3): 135 – 138.

Uellendahl, H. and Ahring, B.K. (2010) Anaerobic digestion as final step of a cellulosic ethanol biorefinery: biogas production from fermentation effluent in a UASB reactor-pilot-scale results, Biotechnology Bioengineering, 107: 59 – 64.

Vlaeminck, S.E., DeClippeleir, H., Verstaete, W. (2012) Microbial resource management of one-stage partial nitritation/anammox, Mcrobial Biotechnology, 5(3): 433 – 448.

Wang, L., Li, Y., Chen, P., Min, M., Chen, Y.F., Zhu, J., Ruan, R.R. (2010) Anaerobic digested dairy manure as a nutrient supplment for cultivation of oil-rich green microalgae Chlorella sp. Bioresource Technology, 101(8): 2623 – 2628.

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Sources & resources (5)Weismann, U. (1994) Biological nitrogen removal from wastewater, In

Biotechnics/Wastewater, 113-154, Springer, Berlin, Heidelberg.Wood, S. and Cowie, A. (2004) A review of greenhouse gas emission factors for fertilizer

production, In IEA bioenergy task (Vol 38, p.20)Yanosek, K. (2002) Enhanced biological phosphorous removal from dairy manure to meet

nitrogen:phosphorous crop nutrient requirements, Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA.

Zhang, T., Bowers, K.E., Harrison, J.H., Chen, S. (2010) Releasing phosphorous from calcium for struvite fertilizer production from anaerobically digested dairy effluent. Water Environment Research, 82(1): 34-42.