2014 10 andrew dixon
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TRANSCRIPT
Waste Water Treatment Works
Waste to Energy
Andrew Dixon, Renewable Energy Specialist
DCWW energy schemes
Renewable Energy Programme : By 2015
Anaerobic Digestion 11 sites, 11 MW
Hydro 20 sites, 2 MW
Solar Photovoltaic 15 sites, 2 MW
Wind 1 site, 2.5 MW
On track for carbon reduction: 25% from 2007 to 2015
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Hydro – in delivery
Hydro - Live
kW capacity
500 +
101 - 500
0 - 50
51 - 100
Wind – in planning
Solar PV - Live
Digestion CHP or AD - live
Status
Renewable Energy Generation Sites
Biomass heating – in delivery
Hydro – in feasibility / design
Strata Florida
Llys y Fran Res
Maerdy
Tyn y Waun
Crai
Preselli WTW
Llwyn-on Sluvad
Nash
Swansea
Cefn Dryscoed
Eign
Cardiff
Afan
Llanfoist
Lliedi’s
Penycefn
Eithinfynydd
Portmadog
Ffynon Lugwi Cowlyd
Alwen
Brenig
Ruthin
5 Fords
Queensferry
Kinmel Bay
Glascoed
Usk
Cilfynydd Ponthir
Cog
Dol-y-Mynach
Glaslyn
Dolbenmaen
Ponsticill
Bolton Hill
Builth Wells
Penthir
Waste to Energy at WwTW
Variety of opportunities
Driers
Incinerators
Liming
Anaerobic Digestion
־ Sewage Gas - CHP
־ Gas to Grid – Biomethane injection
־ Vehicle Fuel
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Cardiff WwTW – The Process
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Thermal Hydrolysis vs Conventional Digestion
More biogas - more electricity!
Stabilises sludge – regulatory requirements
Greater sludge destruction – less to dispose to land
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Sewage Gas – Advanced Anaerobic Digestion
Plant capacity
30,000 TDS capacity – sewage sludge
12 – 18 day Hydraulic Retention Time
Three 1.5 MW engines
־ 20 GWh electricity per year (equiv. To over 3,000 homes!!)
־ ~10,000 tonnes CO2 saved per year
־ Heat from engines used in the process
“Enhanced” treated sludge to land
99.9999% pathogen kill (99% for conventional digestion)
Nutrient enrichment of soils
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Cardiff WwTW – Vital Statistics
Benefits of Advanced Digestion
Economic
Energy Security
Cost saving & Revenue generating
Registration under CHP Quality Assurance
Environmental
Carbon reductions
‘Enhanced’ Sludge Status – disposal to land bank
Efficient use of resources – Heat and Power
Environmental Permits govern operation
־ Forthcoming Industrial Emissions Directive
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Safe Sludge Matrix
Sludge use and agriculture governance
No conventional sludge to grassland
Interval periods – between disposal and harvest ־ Varies from 10 months to 30 months
Sewage company must test soil ־ Dependant on crop/grazing
־ pH of soil
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Other Waste to Energy Initiatives
Dwr Cymru:
Cardiff East WwTW - AAD
Afan WwTW - AAD
Cog Moors WwTW (Dinas Powys) - AD
Other Schemes:
Avonmouth (Wessex Water)
Tremorfa Energy from Waste plant (Viridor)
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