THERMAL AMMONIA RECOVERY FROM WASTEWATER
Christopher Eden, Organics Group

Presentation Structure
1. Background to Organics
2. Thermal Ammonia Recovery – Overview
3. Typical Design Specification
4. Typical programme
5. References
Key Contact information:
Organics Ltd, 2 Sovereign Court, University of Warwick Science
Park, Coventry. CV47EZ. United Kingdom Tel: +44
(0)2476692141 Email: comms@organics.com
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Key messages
• Well proven, viable process offering significant
operational and commercial benefits
• Suitable for almost any high-strength ammonia
wastewater
• Recovered ammonia has a wide range of uses
• GHG mitigation and energy efficiency
Thermal Ammonia Recovery & Reuse

Background to Organics
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Steam stripping
Requires copious amounts of steam but can achieve very high removal and recovery rates.
Membrane ion exchange
Electrically driven and can require around 8.8 kWh per kg of ammonia recovered. A facility removing 5 tonnes per
day would, therefore, require a power supply of approximately 2 MWe.
Membrane contactors
Ammonia diffuses through a hydrophobic membrane into sulfuric acid under osmotic pressure, to give
ammonium sulphate.
Air stripping
1: In the case of pH driven air stripping, it is necessary to raise the pH to 10 or 11.
2. Thermal ammonia stripping requires heat to drive ammonia removal.
Technologies for Ammonia Removal

Organics Thermal Ammonia Recovery - OTAR
1. The conversion of the ammonium ion to ammonia gas.
2. The removal of the ammonia gas from WW by air-
stripping
3. Recovery of ammonia in cold water
4. Concentration of ammonia to required content
Thermal Ammonia Recovery – Overview
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• The equation governing the relationship between
ammonia gas and the ammonium ion may be written as
follows:
NH4
+ + OH- NH3 + H2O
• Dissociated ammonia ion (NH4+) is converted to
undissociated ammonia gas (NH3) as the temperature of
the water increases, so the amount of free ammonia gas
also increases.
Thermal Ammonia Recovery – Overview (cont’d)
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The ratio of ammonia in the gas phase to the total
ammoniacal nitrogen, referred to as ‘f’, may be expressed as
follows:
Thermal Ammonia Recovery – Overview (cont’d)
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Organics Thermal Ammonia Recovery (OTAR)
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The Organics process for ammonia
recovery involves three process stages:
(1) Air stripping removes ammonia and
captures it in air;
(2) First stage recovery into clean water,
pollutants removed and ammonia
concentration is increased
(3) Concentration to the desired product
concentration. Ammonia releases are
minimised by recycling the stripper air
from the outlet of the first stage
recovery to be re-used as stripper air.
Organics Thermal Ammonia Recovery (OTAR)

Water scrubber to produce ammonium hydroxide
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Further processing to produce anhydrous ammonia
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Typical General Arrangement
Condensors
Water scrubber
Rectifier
Separator
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Thermal Ammonia Recovery – Benefits
• Rapid start-up/shut down
• Ease of operation and maintenance
• >95% plant availability.
• No chemicals for pH adjustment
• No sludge production
• Small footprint
• Ammonia can be recovered and
utilised on or off-site
• Withstands large fluctuations of ammonia
concentration
• Waste heat or primary fuel to drive the process
• Horizontal stripping possible if low profile
required
• 20 years operational experience
• Suitable for high-strength ammonia wastewater
( >1,000 mg/l)
• Removal rate > 98%
• Successful trials on THP side-stream liquors
• Contributes to GHG emission reduction (N2O) and
displaced grid power from on-site power production
Performance
Flexibility
Cost-benefit
Operation and Maintenance

Parameter Value
Liquid flow rate
Influent concentration (NH4)
Effluent concentration (NH4)
Effluent temperature
Influent pH
Ambient air temperature
Maximum
Minimum
Relative humidity
Maximum
Minimum
Product type
Ammonia concentration
Ammonia Productions
300 m3/day
4,700 mg/l
<150 mg/l
40°C max
8.7
35°C
0°C
85 %
60 %
Ammonia hydroxide
15% to 20%
2 – 2.5 tonnes/day
Parameter Value
Utility requirements
Electricity
Heat
Water
Chemical requirements
Antifoam agent
Materials of construction
Columns
Packing
Column trays
Pipework
Pumps and blowers
Access structure
Standards applied
Third Party Inspection
(where required)
100 kWe
1.5 MWth
2 cubic metres per hour
1 litres per hour (organic
biodegradable)
Avesta 254 SMO or suitable
equivalent
Polypropylene or 316 ss
316 ss
316 ss
304 ss
Hot dip galvanised
British, European, and/or ASME
Lloyds, CU or equivalent
TYPICAL DESIGN SPECIFICATION: Key performance parameters.
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Preliminary design phase 4 weeks
Design phase: 8 weeks
Procurement and fabrication of items making up the plant: 30 weeks
Transport and installation on site: 20 weeks*
Commissioning & Performance Testing: 4 weeks
Total: 66 weeks
* Installation is not part of this scope of supply, the timescale shown is an estimation.
Timescales are working weeks and do not account for holiday shutdowns or pandemics.
The above timescale does not allow time for approvals by the Client’s engineers, which should
be included in a final project programme.
Typical Programme
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Uses for Ammonia

Organics Thermal Ammonia Recovery (OTAR)
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Options for Thermal Energy
Pyrolysis
Waste to clean thermal energy
One 500 kg per hour pyrolyser provides adequate heat to
power a thermal recovery unit with an input of 600 m3/day
Power generation
Biogas to energy
The generation of 3MWe of power from landfill gas
provides sufficient heat to power a thermal ammonia
recovery unit with an input of 600m3/day.

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WAS - 500kg/hour
Heat for ~600m3/day

References
Ref no Date Site name Flow rate Client NH4 influent NH4
effluent
7888 Nov 22 NENTX, Hong Kong 2,000 m3/d Veolia 4,500 mg/l 150 mg/l
7512 Nov 21 Northumbrian Water, UK. Pilot plant for WWTW 3,500 mg/l 150 mg/l
5976 Dec 20 Severn Trent, UK. Pilot plant for WWTW 3,500 mg/l 150 mg/l
5588 Dec 19 NENT, Hong Kong 1,500 m3/d Suez 4,500 mg/l 100 mg/l
7350 Feb 19 WENT, Hong Kong 1,500 m3/d SITA Waste 5,000 mg/l 100 mg/l
5678 May 18 SENTX, Hong Kong 2,000 m3/d GVL 4,500 mg/l 150 mg/l
5739 Aug 16 WENT, Hong Kong 1,150 m3/d SITA Waste 4,750 mg/l 100 mg/l
5208 July 15 O-Park 1, Hong Kong 550 m3/d OSCAR 3,250 mg/l 100 mg/l
5120 Aug 12 SENT, Hong Kong 2,000 m3/d GVL 5,500 mg/l 100 mg/l
3066 Jun 06 PPVL, Hong Kong 2,760 m3/d SITA Waste 1,750 mg/l 75 mg/l
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18 plants; 80 tonnes a day

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• WENT
• Landfill leachate
• 3,750 m3/day
• 5,000mg/litre
• Phases 1 and 2

• Landfill leachate
• 2000 m3 per day
• In: 4,500 mg/l
• Out: 100 mg/l
• Rate: 97.7%
• Ammonia removed:
− 8.8 tonnes/day
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• O-PARK Lantau Island
• Food waste digester
centrate
• In: 3,510 mg/l
• Out: <10 mg/l
• Removal rate – 97.1%
• Commissioned 2018

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• SENT
• Landfill leachate
• 4,500mg/litre
• 2,500 m3/day
• Phases 1 and 2

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• Pillar Point Valley
• 2,760 m3/day
• 1,750 mg/litre
• Discharge limit
– 75 mg/ litre.

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• 2 No. Pilot plant studies, UK
• Starting March 2023
• Objective:
o Separation of ammonia from
municipal wastewater to
produce ammonium hydroxide
o Production of hydrogen from
ammonium hydroxide

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The Future
§ The technology for separating ammonia from wastewater
is well developed
§ Primary energy and environmental costs continue to rise
§ Process efficiency is improving
§ Ammonia recovery and reuse will become more
prevalent
§ Drivers:
§ Drive towards greater efficiency of existing resources
§ Meeting the challenge of net zero in short order
Sovereign Court II,
University of Warwick Science Park,
Coventry, UK
www.organicsgroup.com

Chris Eden, Business Development Director
Contact: chris.eden@organics.co.uk / +34 629 431 059
Keith Richardson, Commercial Director
Contact: keith.richardson@organics.co.uk / +44 7776 198457
Robert Eden, Managing Director
Email: robert.eden@organics.co.uk / +66 2 564 0828
Mark Moulden, Technical Director
Email: mark.moulden@organics.co.uk / +44 2476 692141
Contact Information