developments in nitrogen removal by reed bed treatment ......no3- + organic carbon → no2- → n2...

ARM Ltd

Developments in Nitrogen Removal

by

Reed Bed Treatment Systems

15 May 2013

The Company

Agricultural Requisites and Mechanizations

1947 – 1990

Agricultural engineering,

buildings and composting

1990 – Present

Reed Beds

• 500+ constructed

• 75% for sewage

• 25% surface run off, leachate, process water

Wetland Types

Passive Wetland Systems

• Horizontal Flow (SSF, SF)

• Vertical Flow (VF)

Intensive Wetlands • Forced Bed Aeration

• Fill and Drain TAYA System

Wetland Mechanisms for TN removal

1. Primarily microbial through sequential microbially mediated

mineralisation of organic bound nitrogen (N) to N gas.

Ammonification (aerobic and anaerobic)

Urea/Amino acids + H2O →2NH3 + CO2

Nitrification (aerobic)

NH4+ + O2 → NO2- + O2 → NO3- + H2O +energy

Denitrification (anaerobic, anoxic)

NO3- + organic carbon → NO2- → N2 gas↑

All proceeding at various rates.

Wetland Mechanisms for TN removal (cont)

2. Removal of N bound in solid material occurs through

filtration and settlement - Apparent

3. Plant and microbial biomass uptake – Apparent

4. Accretion in silts and litter

Wetland Types




Intensive Wetlands • Forced Bed Aeration


Horizontal Flow Reed Bed : Continuous flow


Surface Flow

Sub Surface Flow


Horizontal Flow Systems

• Saturated

• Low Oxygen tensions

• Apparent Oxygen transfer rate is 7g/m2/d

• Suited to Denitrification (carbon source needed)

• Ammonification does occur

• Nitrification occurs but unreliably.

Wetland Types




Vertical Flow : Batch flow

Passive Wetland Configurations


Vertical Flow Systems

• Temporary saturation, re-aerated.

• Relatively higher, more coinsistent Oxygen tensions than HF.

• Apparent Oxygen transfer rate is 25g/m2/d.

• Suited to Ammonification and Nitrification.

• Denitrification is minimal.

• Ammonification

Organic N to ammonia.

Can be achieved in Horizontal Flow and Vertical Flow Reed Beds.

• Nitrification

Ammonia oxidation to Nitrate.

which can be achieved in Vertical Flow Reed Bed.

• Denitrification

Nitrate reduction anoxic conditions to Nitrogen gas.

Which can be achieved in a Horizontal Flow Reed Bed.

• Combining Nitrification and Denitrification leads to perfect recycling by returning the

N2 to the atmosphere from whence it came.

Passive Combination: Vertical and horizontal

• Oaklands Park is a Camphill Community dedicated to looking after

handicapped people.

• Full scale system for 65 pe hybrid system 2 sets of VF beds followed

by 2 sets of HF beds.


Inter-stage data (mg/l) for Oaklands Park averages of 47 samples over 2 years

Influent Stage1 Stage 2 Stage 3 Stage 4

VF VF HF HF

BOD 285 57 14 15 7

TSS 169 53 17 11 9

NH4N 50.5 29.2 14 15.4 11.1

Oxd.N 1.7 10.2 22.5 10 7.2

Nitrification Denitrification


• HF can denitrify effectively if we have a carbon source.

• VF can nitrify effectively at low ammonia levels (up to 50 - 100 mg/l – single

pass)

• Combination systems can achieve total N removal to secondary treatment

level.

• Rely on the diffusion of atmospheric oxygen into the effluent to ‘fuel’

microbial activity.

• Subject to vagaries of local weather.

• Have a relatively large land take.

• Work well if sized and designed properly.

• Robust

Passive Wetland Configurations

Wetland Types


• Horizontal Flow (HF)


Intensive Wetlands • Forced Bed AerationTM


Passive

Natural Systems

Active

Mechanical

Treatment

Systems

Area Requirements MOST LEAST

LEAST MOST Energy and O&M Needs

Water Treatment: Natural vs Mechanical

Intensive Treatment Systems

Wetland Types



Forced Bed Aeration™

Forced Bed AerationTM

• A new technology for enhancing reed bed performance.

• Tried and tested in the USA.

• FBATM compliments existing reed bed technology.

• Increases treatment capacity of reed beds by up to 15 times.

• Adds flexibility to counter variability in loads.

Forced Bed Aeration™

• Reduces variability in performance (counters climatic issues).

• Reduced area required (lowers capital costs).

• No constraints on bed dimensions or aspect ratio.

• 1 to 2m deep.

• Can be retrofitted into existing wetlands.

Standard and Forced Reed Beds 02 transfer rates

Series1 0

20

40

60

80

100

120

140

160

Horizontal Flow 5g/m2/d

Vertical Flow 17-25 g/m2/d

Forced Bed Aeration up to 160 g/m2/d

Typical Oxygen Transfer Rates ForDifferent Reed Bed Systems

Passive & Mechanical Systems Power Costs

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

kW

h /

m³

of

wast

ew

ate

r

Active Systems Passive Systems

FBA

Systems

Wolseley Area: 72m2

Flow 0.54 - 7 m3/d

HRT: 3 – 37 days

Aeration 10 hrs

Wolseley Bridge Ammonia Removal

14 hrs aeration

90% 98.9%

10 hrs aeration

Balhall Area: 151m2 +31m2

Flow 5 m3/d

Aeration 18 hrs

Balhall WwTW: Single Bed, Passive, VF system

207

86

55

26 35

26

0

50

100

150

200

250

BOD SS NH4

Balhall Passive Performance Spot Sample Averages

Suspended Solids, BOD, Ammonia

Influent Effluent

Balhall WwTW: Two bed, Aerated, VF system

460.6

26.1 11.6

144.3

51.4

21.2

90.1

13.5 1.8

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

400.0

450.0

500.0

Settled Reed Bed 1 Out Reed Bed 2 Out

Balhall FBATM Performance Spot Sample Averages

Suspended Solids, BOD, Ammonia

BOD Suspended Solids Ammonia

0

50

100

150

200

250

300

350

400

450

500

Sep-99 Sep-00 Sep-01 Sep-02 Sep-03 Sep-04

TAN

Concentr

ati

on [

mg/L]

Influent Effluent

New Pretreatment System and

Forced Bed Aeration ™ System

Iron fouling

No Aeration Startup

Jones County Landfill: Total Ammonia (TAN)

Eichten Cheese CBOD Removal

0

1000

2000

3000

4000

5000

6000

7000

8000

Mar-9

8

Mar-9

9

Apr-9

9

Apr-9

9

Jun-9

9

Jul-9

9

Sep-9

9

Dec-9

9

Mar-0

0

Jun-0

0

Sep-0

0

Dec-0

0

Mar-0

1

Jun-0

1

Sep-0

1

Dec-0

1

Mar-0

2

Jun-0

2

Sep-0

2

Dec-0

2

Mar-0

3

Jun-0

3

Sep-0

3

Dec-0

3

Mar-0

4

Jun-0

4

Jun-0

5

CB

OD

5 (

mg

/L)

Eichten Cheese CBOD Removal

In Out

Intermitten

t Aeration

Forced Bed Aeration TM

Buffalo Niagara International Airport Glycol removal from surface water

1.7 Ha, removing 4,500 kg/day

Heathrow trials

Buffalo Airport De-icing Fluid Treatment

Buffalo Niagara International Airport

Intensive Wetland Systems

Forced Bed Aeration (FBATM)

• Increases Oxygen availability significantly.

• Increases wetland nitrification capacity 10 fold.

• More consistent performance, especially with beds in series.

• Reduced area requirements, can go deeper also.

• Denitrification options under investigation.

• Looking for an AD digestate trial.

• Power consumption.

Wetland Types



TAYA Treatment System

• Developed from reciprocating wetland technology.

• Engineered to maximise the efficiency of the

microbial biomass through nutrient management

and effective natural aeration.

• Proprietary open channel bottom pumping design,

maximises the use of gravity during operation, to

minimize power consumption, maintenance and

operational costs.

• Complete mix is achieved and thus maximum

dilution.

The design of the wetland incorporates the filling and draining

of subsurface flow basins.

Minimum Head

• Pumping from the bottom

• Open Channel arrangement

Feed arrangement

• Max dilution

• Complete mix


TAYA Effluent TAYA Influent Anaerobic Ponds Influent mg/l

20 500 12,000 CBOD

30 250 15,000 TSS

40 - 100 900 900 -1,300 NH4

300 300 300 Flow

(m3/d)

Lahav Kibbutz : Summary Operational Data

Lahav Kibbutz Piggery: Operational Data

Lahav Kibbutz Piggery: Operational Data

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1/2/10 2/21/10 4/12/10 6/1/10 7/21/10 9/9/10 10/29/10 12/18/10 2/6/11 3/28/11 5/17/11 7/6/11 8/25/11

Value (ppm) Lahav - TN Removal

Influent

Effluent


TAYA System

• Effective natural aeration.

• Flexibility through process control.

• Nitrification/Ammanox and denitrification.

• No sludge production.

• Small footprint even compared to FBATM.

• AD digestate systems being installed in Italy this year.

• Need a climate trial in the UK.

Helmholtz Centre for

Environmental Research (UFZ)

Three research campuses Leipzig, Halle, Magdeburg 1,000 employees 180 post-grads and post-docs

Additional partners

… and massive support from many colleagues, friends, and family

Fo

to:

Künze

lman

n/U

FZ

Septic Tank

(primary treatment)

Unsaturated vertical flow filters

Saturated vertical

flow with aeration

Horizontal flow Fill and

Drain

1m deep +

aeration

0.25m deep 0.5m deep

1-3mm Sand

periodic resting

1-3mm Sand, no

resting

4-8mm gravel,

no resting

8-16mm

gravel,

no resting

Comparative Ammonia Removal

NH4-N

0

10

20

30

40

50

60

0 1 2 3 4 5 6

nHRT (days)

Co

nce

ntr

ati

on

(m

g/L

)

HF 1.0m Aerated + plants

HF 1.0m Aerated - plants

HF 0.25m + plants

HF 0.25m - plants

HF 0.5m + plants

HF 0.5m - plants

Comparative Nitrate Generation

NO3-N

0

5

10

15

20

25

30

0 1 2 3 4 5 6

nHRT (days)

Co

nce

ntr

ati

on

(m

g/L

)



HF 0.25m + plants

HF 0.25m - plants

HF 0.5m + plants

HF 0.5m - plants

Comparative Total N removal

Total N

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6

nHRT (days)

Co

nc

en

tra

tio

n (

mg

/L)



HF 0.25m + plants

HF 0.25m - plants

HF 0.5m + plants

HF 0.5m - plants

Total N removal summary

0

1

2

3

4

5

6

Unplanted Planted Unplanted Planted Unplanted Planted Unplanted

Horizontal Flow Aerated HF Vertical Flow FaD

System Design

TN

Ma

ss

Re

mo

va

l R

ate

(g/m

2.d

ay)

Summary

• Passive Reed Bed/Constructed wetland systems can effectively

reduce total N levels when used in combination demonstrating

the principle of total N reduction in wetlands.

• Intensive systems through increased oxygen transfer rates can

achieve higher removal rates more consistently.

• FBATM systems show significant potential for AD digestate

treatment, though not yet proven, but looking for trials…

• The TAYA systems has already demonstrated high level

nitrification and denitrification and the first commercial AD

digestate treatment installations are being installed this year

in Italy. We are looking for UK climate trials …

Thank you

developments in nitrogen removal by reed bed treatment ......no3- + organic carbon → no2- → n2...

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