THE HENRIKSDAL WASTEWATER TREATMENT PLANT Kv ar nh olm sv äg en Stockholm Vatten AB (the Stockholm Water Company) is an environmental and engineering company. The company is characterized by its holistic approach and its consideration for the ecocycle.The company seeks to create the necessary conditions for better water and an improved water environment, not least in the Baltic region, through its co-operation with other local councils in the Stockholm region and through international joint projects. The Stockholm Water Company produces and supplies drinking water to more than a million people in Stockholm and Huddinge, and to a further nine neighbouring local councils. We also handle and treat the waste water from Stockholm, Huddinge and six other neighbouring local councils. We own and operate the Norsborg and Lovö waterworks and the two sewage treatments plants at Henriksdal and Bromma, as well as the tap water and sewage mains networks, pumping stations and water reservoirs, etc., in Stockholm and Huddinge. We are also responsible for the restoration of lakes and for water conservation. Sickla. See picture on back cover Vä rm dö vä ge n The Henriksdal waste water treatment plant, which serves Stockholm, Huddinge, Haninge, Nacka and Tyresö, is today one of the largest and most modern in Europe. It was opened in 1941, when it had the capacity for the low-grade treatment of scarcely 150 000 m3 of waste water per day. The plant was extended in 1953, and its capacity was doubled. It has since been further extended to include chemical and biological treatment. The most recent expansion programme, which lasted from April 1992 until April 1997, was undertaken to reduce nitrogen emissions by at least 50% and to provide improved phosphorus treatment. Henriksdal is one of the world’s largest underground treatment plant. It covers approx. 300 000 m2, and it has approx. 18 kilometres of tunnels. The whole of the basin block lies inside chambers blasted into the rock. The surface facilities include the control centre building, mechanical treatment, the sludge tanks, the upper parts of the sludge thickeners, the digesters, gas holder, the gas collection plant and gas storage. The ventilation chimney is 80 metres tall and 7 metres in diameter. Sludge treatment takes place in a separate facility at Sickla, located about two km from Henriksdal. The population on top of Henriksdal is 1 630 persons. The plant lies 2 kilometres from Slussen on the boundary between Stockholm and Nacka. 1 Treatment requirements: 9 Values for the two treatment plants weighted in proportion to the flow. From 30 June 2000: 8 mg BOD7/l and 0.3 mg P-tot/l as quarterly mean values, 3 mg NH4-N/l as the mean value from July to October, and 10 mg N-tot/l as the annual mean value. 2 Design data: Number of persons connected: 700 000 Mean flow: 241 000 m3/24 hours BOD7 load: 48 tonnes BOD7/24 hours N-tot load (including rejects): 9 tonnes N-tot/24 hours Qdim: 4.5 m3/s Qmax: 10 m3/s Qmax to biological stage: 8 m3/s Qmax to filters: 10 m3/s 3 Flow measurement The Henriksdal flow and the outlet flow are measured with an echo sounder, and the Sickla flow is measured electromagnetically 4 Mechanical treatment Also see picture on back cover 20 screens with distance between the bars: 3 mm Make: Hydropress; Type: step screen Henriksdal; 8 screens; Sickla: 10 screens for waste water and 2 screens for stormwater Pumping station The pumps lift the water from the primary-sedimentation to the biological stage. Pumps: 7 units of type Flygt PL7080 Lift height: 1.67 m at mean flow Lift height at low flow: 1.49 m Lift height at 8 m3/s: 1.80 m Pump capacity: 7 units, 0.7 - 1.2 m3/s, 45 kW 10 Aeration tanks no of tanks: 7 Total volume: 204 000 m3, i.e. 29 000 m3/tank Detention time at Qdim: 13 h Detention time at 8.0 m3/s: 7 h Zones/tank: 1 mixing zone for 1 400 m3 6 aerated or anaerobic zones, each for 4 500 m3, and 1 de-aeration zone for 710 m3 zone length width mixing zone zones 1-6 de-aeration zone 28 m 38 m 14 m 10 m 10 m 10 m depth 5m 12 m 5m Oxygen content: 1-3 mg 02/l as reference value Air flow: approx.18 000 - approx.36 000 Nm3/h for normal operation Aerator type: fine-bubble rubber membrane aerator Make of aerator: Sanitaire Number of aerators: 19 000 units Grit chambers no of grit chambers: 4 Also see picture on back cover Total volume: 2 400 m3 Detention time at Qdim: 9 min Detention time at Qmax: 4 min Henriksdal: 2 grit chambers, each with a volume of 590 m3 Sickla: 2 grit chambers, each with a volume of 630 m3 5 6 Pre-precipitation with ferrous sulphate: 6a Henriksdal inlet 6b Sickla inlet Total: 11-20 g Fe/m3 11 7 Pre-aeration pre-aeration channels Total volume: 1 100 m3 Detention time at Qdim: 4 min Detention time at Qmax: 1 min Henriksdal: 2 channels, each with a capacity of 260 m3 Sickla: 590 m3 8 Primary sedimentation no of compressors: 5 air/compressor, max. 15 000 m3 air/ Capacity: min. 6 800 compressor. Power requirement: min. 250 kW/compressor, max. 530 kW/compressor. Speed: max. 18 000 rev/minute Make: HV-Turbo A/S (Denmark). Type: KA 10SV m3 12 no of tanks: 13 Total volume: 30 000 m3 Total area: 8 200 m2 Detention time at Qdim: 1.8 h. Detention time at Qmax: 0.8 h. Surface load at Qdim: 2.0 m/h. Surface load at Qmax: 4.4 m/h. Type of scrapers: Line scrapers Aeration system Secondary sedimentation tanks tank tank length width depth F1-F8 F9 F 10 - F 13 60 m 60 m 70 m 10 m 10 m 10 m 3.6 m 3.7 m 3.7 m no of tanks: 14 Total volume: 58 000 m3 Total area: 11 000 m2 Detention time at Qdim: 3.6 h. Detention time at 8.0 m3/s: 2.0 h Surface load at Qdim: 1.5 m/h. Surface load at 8.0 m3/s: 2.7 m/h. Type of scrapers: Line scrapers E 1 - E 11 E 12 - E 14 length width 80 m 80 m 10 m 10 m depth 5m 6m For a sustainable 10 15 9 14 13 12 FeSO4 FeSO4 STEP SCREEN PRIMARY SEDIMENTATION GRIT CHAMBER SECONDARY SEDIMENTATION BIOREACTOR SAND FILTER HEAT PUMP PLANT BALTIC SEA PREAERATION BIOGAS TO HAMMARBY SJÖSTAD AIR BLOWER PRIMARYSLUDGE SURPLUS SLUDGE SCRUBBER CENTRIFUGE BIOGAS FOR VEHICLES BIOGAS DIGESTER GASHOLDER SLUDGE TANK FAT INTAKE FAT TANK SLUDGE HOLDING TANK INTERNAL HEATING AND ELECTRICITY THICKENER POLYMER CENTRIFUGE society Sickla plant. 11 6b 27 29 25 28 8 16 20 18 7 23 19 6a 17 24 5 4 26 13 Secondary precipitation Precipitation with ferrous sulphate on filters with 1-4 g Fe/m3 14 Pumping station 12 pumps lift the water from the biological stage to the filters. 8 speed-controlled propeller pumps Type: Flygt 7060 Capacity: 0.35 - 0.75 m3/s at 2.7 - 3.7 mvp. 4 speed-controlled propeller pumps Type: Flygt 7080 Capacity: 0.55 - 1.1 m3/s at 2.9 - 3.7 mvp. Lift height: 3.05 m Sand filters no of filters: 60, divided in 4 block Type: Downstream, 2-media, deep-bed filters Total area: 3 600 m2 Filter area: 60 m2/filter Load, max.: 10 m/h Filter material, upper layer: 1 m expanded clay, Ø 2.5 - 3.5 mm Filter material, lower layer: 0.5 m sand, Ø 1.2 - 1.9 mm 15 2 digested sludge thickeners at Sickla: Total volume: 1 600 m3 Diameter: Ø 18 m Depth: 7 m Total area: 510 m2 21 Dewatering of sludge Also see picture on back cover no of centrifiuges: 4 Capacity per centrifuge: 30 m3/h Alfa Laval NX4500 22 See picture on back cover Silo for dewatered sludge Total volume: 800 m3 no of silos: 2 See picture on back cover Gas engines no of gas engines: 4 Electrical output: 700 kW at 100% load/each Thermal output: 950 kW at 100% load/each Jenbacher (Austria) Type: JMS 316 GS-B.L 4-stroke internal combustion engine, 16 cylinders 23 24 Boilers 25 Ventilation no of boilers: 3 Boiler 1: output 2.9 MW Boiler 2: output 2.5 MW Boiler 3: output 1.5 MW Make: Osby Parca AB, Weishaupt combination burner for oil/gas Air capacity: 425 000 m3/h 3 air replacements/h in coarse cleaning, sand trap and container hall 2 air replacements/h in the rest of the plant Digesters no of digesters: 7 Total volume: 39 000 m3; Temperature: 35 - 37 °C Detention time: approx. 19 days 16 digesters volume R 1 - R 4, R 7 R 5, R 6 5 000 m3 7 000 m3 17 height: bottom to surface of sludge 22 m 28 m Heat exchanger digester sludge Heat effect daily 760 kW/h 18 28 Gas collection plant Gas storage Total volume: 7 000 Nm3 no of centrifuges: 5 Capacity: 5 x 50 m3/h 20 Receiver station for organic waste Amount of organic waste: approx. 24 000 m3/year Capacity: line 1: 400 Nm3 biogas/hour line 2: (planned 2005) approx. 500 Nm3/hour Gas holder Excess sludge centrifuges 26 27 Volume: 5 000 m3 Utilized volume: 4 000 m3 19 All exhaust air passes through a heat recovery plant, which returns approx. 55% of the energy contained in the exhaust air to the supply air unit in fan room 1. In fan room 2, the supply air is pre-heated to +5°C with treated waste water and is re-heated to +20°C with heat recovered from the blowers. Sludge thickeners 2 sludge tanks at Henriksdal: Total volume: 10 000 m3 Diameter: Ø 23 m Depth: 10.5 m at the periphery, and 13 m at the centre Total area: 830 m2 29 LNG storage (planned 2004) Storage volume: 2 x 33 000 Nm3/m Flow capacity: approx. 900 Nm3/m 30 Sewage to Henriksdal 31 Digested sludge from Henriksdal See picture on back cover See picture on back cover 20 4 5 31 21 30 22 T AL LABEL NV 341 065 I RONMEN Henriksdal Wastewater Treatment Plant Värmdövägen 23, SE-131 55 Stockholm, Sweden Phone: +46 8 522 133 00, Fax: +46 8 522 133 02 EO Print 2004 Lic.nr 341065 Upplaga: 1 000 ex Sickla plant. E Lundquist & Co Foto: Thomas Henrikson Illustrationer: illtek Miljömärkt trycksak NORDIC Stockholm Water Company SE-106 36 Stockholm, Sweden Phone: +46 8 522 120 00, Fax: +46 8 522 120 02 [email protected] www.stockholmvatten.se Visiting addres: Torsgatan 26 A member of the Stockholms Stadshus AB group