This document summarizes Dr. Donna Rawlinson's presentation on Northumbrian Water's innovative approach to sludge treatment. It discusses how Northumbrian Water uses advanced anaerobic digestion (AAD) to treat sludge, producing renewable energy and reducing costs. Their AAD systems at two sites produce enough electricity to power 30,000 homes annually. Northumbrian Water is also expanding AAD by adding food waste digestion and connecting the biogas to a gas grid to further reduce fossil fuel usage and increase renewable energy production.

1. DEVELOPING BIORESOURCES
THROUGH AD
#UKADBiogas @adbioresources
CHAIR:
DR ADRIAN HIGSON, NNFCC
PANEL:
PROF CHRISTOPHER RAYNER, C-CAPTURE
STEVE BROOME, CPI
PHIL SCOTT, AMEC
JOHN WILLIAMS, ADAS UK
DR DONNA RAWLINSON, NORTHUMBRIA WATER

2. Dr Donna Rawlinson
15/07/2015
NORTHUMBRIAN
WATER’S INNOVATIVE
APPROACH TO SLUDGE
TREATMENT
UK AD and Biogas 2015

3. CONTENTSCONTENTS
3
1 Introduction to NW
2 General Approaches to Waste Water and Sludge Treatment
3 NW’s Advanced Anaerobic Digestion (AAD) and the latest
innovations (Gas to Grid and Food Waste AD)
4 Improving performance of NW’s AD and AAD

4. 4
INTRODUCTION TO NWL

5. 5
SUSTAINABILITY OF NORTHUMBRIAN WATER TREATMENT PROCESSES
INTRODUCTION TO NWL
NW’s approach to sustainability:
• behave fairly and responsibly;
• use resources wisely;
• improve quality of life, and
• contribute to economic development
This includes innovative approaches to:
• reduce power, through improved
– pumping efficiency
– treatment processes
• reduce transport of waste/equipment
• reduce carbon impact
NW’s Vision is to be
“the National Leader in the Provision of Sustainable Water and Waste Water
Services”

6. 6
GENERAL APPROACHES TO
WASTE WATER AND SLUDGE
TREATMENT

7. WASTE WATER TREATMENT PROCESSES
7
GENERAL APPROACHES TO WASTE WATER AND SLUDGE TREATMENT
NWL
• 437 Sewage Treatment
works
• 2,000,000m3 Liquid Sludge

8. 8
SLUDGE STRATEGY
GENERAL APPROACHES TO WASTE WATER AND SLUDGE TREATMENT
2006:
Unprecedented repeated rise in the cost of energy impacting greatly on thermal
drying (which uses natural gas)
• Discomfort with high maintenance costs of RSTC as well as high opex – is it still
a sustainable strategy?
• Demanding NWL opex efficiency targets
• Opportunities identified in emerging advanced digestion
processes beginning to be reported (Industrial Tourism)
• Incentives for renewable energy generation (ROCs)
• Growing corporate awareness of environmental responsibilities
and choices

9. 9
NWL’S ADVANCED
ANAEROBIC
DIGESTION

10. 10
NWL AAD produces 10MW renewable
electricity
• 90,000,000kWh/annum
• Both Bran Sands and Howdon are almost
energy self sufficient
• Covers more than 40% of all of NWL’s waste
water treatment costs
• Meets 20% of all of NWL energy demands
This is the equivalent of 30,000 homes
ADVANCED ANAEROBIC DIGESTION
NWL’S ADVANCED ANAEROBIC DIGESTION

11. 11
SLUDGE STRATEGY
ENVIRONMENTAL BENEFITS OF NWL’S AAD
• Project approvals supported by simultaneous
laboratory ‘Confidence Tests’/pilot plant trials carried
out by Aqua Enviro
• Environmental benefits
– More sustainable
– Energy from waste
– Reduced CO2 footprint (20% reduction from NWL’s total)
– Less transport movements
– Reduced odour potential at sites
– Improved sludge products – safety, odour and value
– Bran Sands design included cake import facility
– Retention of drying capability at RSTC as contingency
• Solution for all NWL sludge arisings

12. HOWDON AAD GAS TO GRID
12
LATEST INNOVATIONS
• £9million capital spend
• RHI revenue potential £4.8million/year for 20 years
• Approx. six times revenue from CHP
• 97% efficiency
• 1700Nm3/hr biogas produced – 60% methane
• 1080Nm3/hr enriched biomethane injected into grid – 97% methane
• Green gas delivered to network – reduces demand on fossil fuels
• Seasonal variations in domestic demand
• CHPs converted to run on natural gas for periods of low demand
• Optimisation- Balancing propane usage

13. UPDATED AAD PROCESS
GAS TO GRID – BIOMETHANE INJECTION
CAMBI AD
Elect
Dist’n
Boiler
Treated
Sludge
Grid Gas
Steam
Low Grade
Waste Heat
Emissions
to Air
Northern
Power
Grid
Northern
Gas
Networks
Site Electricity
Demand
Biogas
Biogas
Upgrade
Propane
Biomethane Grid Gas
CO2
Meter
Emergency
Flare
Steam
Network
Entry
Module
CHP
Sludge
Power

14. BRAN SANDS FOOD WASTE AD
14
LATEST INNOVATIONS
• 260,000t/year food waste available within 45 miles of site
• Proximity to Food Waste source vital
• Proposed 2MWe Food Waste adjacent to existing AAD:
– Hammer Mills
– Pasteurisation stage
– 2 x 5000m3 digesters
• Waste separation maintained
• Consultant engaged to facilitate and manage
procurement of waste
• £12million capital spend
• Double ROC available
• 260,000t/year food waste available within 45 miles of site
• Proximity to Food Waste source vital
• Proposed 2MWe Food Waste adjacent to existing AAD:
– Hammer Mills
– Pasteurisation stage
– 2 x 5000m3 digesters
• Waste separation maintained
• Consultant engaged to facilitate and manage
procurement of waste
• £12million capital spend
• Double ROC available

15. 15
IMPROVING
PERFORMANCE OF
NWL’S ANAEROBIC
DIGESTION
CAPABILITY

16. NEXT INNOVATIVE IMPROVEMENTS
16
IMPROVING PERFORMANCE OF NW’S ANAEROBIC DIGESTION
• Gas to Grid at Bran Sands late 2015
• AAD for commercial projects
• Working with partners to deliver farm waste AD
• Working with partners to deliver other AD projects
• Continued optimisation of processes to maximise
biogas production
• Optimise transport routes
• New processes – continual watch of technology
• Microbial Fuel Cells

17. THANK YOU

18. DEVELOPING BIORESOURCES
THROUGH AD
#UKADBiogas @adbioresources
CHAIR:
DR ADRIAN HIGSON, NNFCC
PANEL:
PROF CHRISTOPHER RAYNER, C-CAPTURE
STEVE BROOME, CPI
PHIL SCOTT, AMEC
JOHN WILLIAMS, ADAS UK
DR DONNA RAWLINSON, NORTHUMBRIA WATER