Participants: Anyang Elwang New Energy and Environment Co. The project was started in 2007 and put into operation in April 2009, and in December 2009, the biogas decarbonization and natural gas grid connection was successfully tested. It treats 600 tons of urban sludge per day, and the project covers an area of 2.47 hectares. The project is a centralized anaerobic digestion of the dewatered sludge produced by the sewage treatment plant in the downtown area of Dalian City, and the biogas can be purified and processed to supply 16,500 cubic meters of biogas (natural gas quality) per day, and at the same time, it produces 60,000 tons of humus per year, which can be used as nutrient soil for gardening or landfill cover soil. The project not only combats environmental pollution, but also realizes energy saving and emission reduction. Its construction method and technical level have attracted great attention from the Ministry of Construction and the General Administration of Environmental Protection, and it has played a good demonstration role for the treatment of urban municipal sludge in China.
Application Case of Sludge Digestion Technology in Xiaohongmen Wastewater Treatment Plant
Participating Organization: Xiaohongmen Wastewater Treatment Plant
Size: 800t/d
Process Technology: Thickening, Dewatering, and Anaerobic Digestion
Description of the Case: The sludge treatment process of Xiaohongmen Wastewater Treatment Plant adopts the thickening-digestion-dehydration process. The sludge treatment process of Xiaohongmen Plant adopts the thickening-digestion-dehydration process, of which the sludge digestion process was completed in November 2008 and formally put into operation. The sludge is stabilized, resourced and reduced through medium temperature anaerobic digestion. Through the regulation of the relevant process, the digestion tank runs stably, the methane content in the biogas produced is stable, and after having the conditions for ignition, we successfully debugged the biogas dragging blower, realizing the regenerative use of energy. In 2009, Xiaohongmen plant produced 3,687,000 cubic meters of biogas, and in March 2009, the biogas trailing blower was in operation, and by the end of 2009, it had saved 3,559,000 kilowatts of electricity, which was equivalent to 2,317,000 yuan.
Qingdao Maidao Wastewater Treatment Plant Sludge Treatment and Disposal Project
Participating units: Veolia Water Solutions & Technologies (Beijing) Co.
Size: 109 tons/day
Process technology: anaerobic digestion
Case description: Qingdao Maidao Wastewater Treatment Plant adopts medium-temperature anaerobic digestion, which is a landmark project for sludge utilization in Shandong Province. It is a landmark project in Shandong Province, which makes full use of the biogas produced by sludge digestion. The project set up two primary medium-temperature anaerobic digesters, with an effective volume of 12,700m3 per tank, to treat sludge from primary sedimentation tank, backwash sedimentation tank and grease from oil removal and sand sedimentation tank, with the temperature in the tank maintained at 35±2℃ and the sludge retention time at 20 days. The biogas generated from sludge digestion is firstly used in four 500KVA biogas generators, which are connected to the grid after transforming and can satisfy 66% of the electricity consumption in the plant, and the hot water generated in the process of generating electricity is used to supply heat for the digesters and for heating the plant. The biogas is also used in the biogas boiler to supplement the heat of the digester, and the remaining biogas is burned by torch. Generating electricity from biogas saves energy and costs for the operating manufacturer's business, and from the point of view of protecting the environment, the sludge is safer after it has been digested.