Complete set of technologies for sludge treatment and disposal, as well as resource and energy recovery and utilization
How to reduce the total urban pollutant load, reduce the pollution load entering the urban water body and downstream watersheds, protect the urban and regional water environment, restore the ecological functions of the water body, and establish a healthy and sustainable water environment system and management model at the same time of rapid economic and social development is a bottleneck problem that needs to be solved urgently in urban water pollution control.
01. Problems and technical requirements
In recent years, under the role of national energy conservation and emission reduction and active fiscal policies, urban sewage treatment has developed rapidly, and urban water environment governance has achieved remarkable results, but accompanied by a large amount of sludge produced in the urban sewage treatment process, it has not been generally effectively treated and disposed of. In response to the problem of sludge treatment and disposal in China, we must break through the current two bottlenecks: (1) form a clear technical route for sludge treatment and disposal and resource utilization; (2) break through the single key technology of sludge treatment and disposal.
02. Consists of a complete set of technologies
2.1 Overall technical idea
With the development of environmental science and technology, sludge is no longer just treated as waste, but should be treated in a balanced manner from the perspective of material and energy cycles.
2.2 Technical route
The goal of sludge treatment and disposal is to achieve the reduction, stabilization, harmlessness and resource utilization of sludge, avoid secondary pollution of sludge through reduction, stabilization and harmlessness, recover and use the energy and resources in sludge through recycling, and realize the recycling of organic matter, nitrogen, phosphorus, potassium and other nutrients rich in sludge. Sludge treatment and disposal is divided into two stages from the technical and operational levels: the first stage is to reduce and stabilize the raw sludge in a centralized way in the sewage treatment plant area, the purpose of which is to reduce the risk of secondary pollution that may be caused by the export of the treated sludge; The second stage is to carry out reasonable and safe disposal of the treated sludge, so that the sludge can achieve the purpose of harmlessness and resourcefulness.
Sludge disposal and resource utilization technical route: On the basis of comprehensive consideration of sludge characteristics, geographical location, environmental conditions and economic and social development level, the method of sludge disposal and resource utilization is determined according to local conditions. Encourage sludge that meets the standards for land use, and actively promote the comprehensive utilization of sludge building materials in areas with conditions; Sludge that does not have the conditions for comprehensive utilization of land use and building materials can be disposed of by other methods such as incineration and landfill.
Sludge treatment technical route: On the basis of the conventional treatment process of sludge reduction, such as sludge concentration, conditioning and dewatering, according to the basic requirements of "disposal decision treatment, treatment meets disposal", according to the sludge quality standards, select the appropriate sludge treatment technical route. When the sludge meets the land use, it is encouraged to treat the sludge by anaerobic digestion or high-temperature aerobic fermentation (composting); When landfill is used as the disposal method, the sludge can be treated by high-temperature aerobic fermentation, lime stabilization, etc., and fly ash and aging waste can also be added to modify the sludge; When the comprehensive utilization of building materials is used as the disposal method, sludge thermal drying, sludge incineration and other treatment methods can be adopted.