212 m Cavern dimensions Water treatment 1.Inlet tunnel 2.Screens, sand and grit removal 3.Primary settling/ direct precipitation 4.Bio step, activated sludge 5.Clarifiers 6.Extra space(not in use) 7.Sand filters Sludge treatment 8.Digesters 9.Sludge treatment 10.Sludge treatment 11.Ventilated air treatment – odor control 12.Biogas, upgrading (out) 12
Discharge consent – Compliance limit New discharge consent from 01.01.2009: Nitrogen:70% of all nitrogen must be removed Phosphorus:90% of all phosphorus must be removed Organic matters:70% of organic matters as BOD 5, must be removed And the total amount of overflow must be less than 2% of the total loads of nitrogen, phosphorus and organic matters NB: The population growth coupled with climate changes resulting to increased to both hydraulic and pollutant loads poses as daunting challenge in meeting present and future stringent discharge compliance limits.
Treatment capacities – operational modes Dry weather flow 1450 l/s or approx. 125.000 m 3 /d – it is subjected to biological and chemical treatment with filtration as final step (max capacity 1900 l/s) – Nitrogen, phosphorus and organic matters are removed Flow rates between 1900-4000 l/s is treated chemically and partly filtration (< 3000l/s) – Phosphorus is removed and organic matters is partly removed Flow rates between 4000 - 6000 l/s is treated through 3 mm screens: Objects such – Objects such as rags, paper, plastics, and metals are removed
Sludge treatment process Thickening Reduces the content of water in sludge to reduce hydraulic load on the digesters. Primary sludge thickened in belt thickener with polymer Bio sludge thickened in centrifugal thickening with polymer Digesters Thermophilic anaerobic digestion process, whereby the incoming sludge is pre-heated before entering the digesters Digestion in the digesters, at 55 ° C in 15 days Dewatering Reduces the content of water in sludge to reduce transport costs Centrifugal dewatering with polymer (30-35% DS) Sludge storage tanks Acts as buffer in order to obtain uniform loading of the system and stores sludge during unexpected failure system. Sludge Production Generated at the plant is approximately 5500 -6000 tons DS/yr
Facts and Goals for the City of Oslo. CO 2 emissions from private and public transport is approximately 50- 80% of the total emissions in the city of Oslo. The City of Oslo’s main goal is: To cut 50% of greenhouse emissions by the year 2030.
LP COOAB ® process – Low Pressure CO 2 Absorption Gas tank Activated coal - filter Gas drier CO 2 absorption CO 2 removal/ COOAB recovery Odorizing the bio- methane High pressure compressor CO 2 0,5 bar 2 bar 200 bar
18 Biomethane value chain ProducerEnd Biomethane Money flow
Exhaust emission and noise S/NUnits DieselBio-methaneReduction % NO x g/km8.11.978 Particulate matter g/km0.30.00598 CO 2 kg/km2.60100 Noise dBA11110092
Oslo kommune Vann- og avløpsetaten Oslo: 600 000 p.e. 10 – 12 million Nm 3 biomethane BusesPersonal vehicles Sewage sludge150 – 2006 000 Household organic waste 200-2508 000 Total350 - 45014 000 The potential of Biomethane in Oslo
Challenges facing Bekkelaget WWTP This include among others; Population growth in Oslo is taxing Bekkelaget wastewater treatment Plant and creating a need for new plants. Oslo will have in the range of 1.1 million inhabitants (including Nittedal municipality) in 2020. This represents a population increase of 18-25% since 2009 (Figure). Bekkelaget WWTP was dimensioned for 270 000 p.e. in 2000, in 2013, Bekkelaget serves 331 000 p.e. Climate change – Many of the earliest sewer systems were combined sewers, designed to collect both sanitary wastewater and storm water runoff in a single system. Increased Hydraulic Loads hence increased pollutant loads (N Tot and P Tot ). Stringent discharge consent for 70 % Nitrogen and 90 % phosphorus removal including overflow and the total amount of overflow must be less than 2% of the total loads of nitrogen, phosphorus and organic matters