Inner Mongolia wastewater treatment municipal sewage includes industrial sewage and our domestic sewage, which is the excrement and domestic waste we usually live in. So how do you treat these sewages? Let's take a look at the relevant content of municipal sewage.
I. What is the difference between urban sewage and municipal sewage? Urban sewage refers to the waste water generated by daily life, such as rainwater, bath water, toilet water, waste water from cooking, etc. ; Municipal sewage refers to the sewage from which all municipal sewage and industrial wastewater are treated centrally.
2. Learn about municipal sewage treatment ? Urban domestic sewage is a product of urban development. With the acceleration of urbanization and industrialization, its output is increasing, and pollution is becoming increasingly serious, which has severely restricted the sustainable development of urban society and economy. . With the rapid development of the global economy, environmental protection issues, especially urban sewage treatment, have become hotspots in various countries. The typical urban sewage treatment process mainly includes mechanical treatment, biochemical treatment, and sludge treatment. The system composed of mechanical treatment and biochemical treatment belongs to the secondary treatment system, and the removal rate of BOD5 and SS can reach 90% to 98%. The treatment effect between intermediate and secondary treatments is generally called enhanced primary treatment, primary semi-treatment or incomplete secondary treatment. There are mainly two types of high-load biological treatment and chemical treatment. BOD5 removal rate is up to 45% to 75%. The secondary treatment system with biological phosphorus and nitrogen removal function is usually called deep secondary treatment. In order to remove specific substances, the treatment system set after the secondary treatment belongs to the tertiary treatment, such as chemical phosphorus removal, activated carbon adsorption, and the like. From the perspective of wastewater treatment, pollutants in Inner Mongolia can be divided into suspended solid pollutants, organic pollutants, toxic substances, polluted organisms and polluted nutrients. A large amount of organic matter contained in urban sewage is discharged into the water body, which will reduce the dissolved oxygen content in the water body, and even reach an anoxic state, which will seriously pollute the water body and make fish in the water unable to survive. Organic matter concentration in sewage is generally expressed by biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total oxygen demand (TOD) and total organic carbon (TOC). Nutrients mainly refer to nitrogen and phosphorus, which can cause algae and plankton to multiply, forming "bloom" and "red tide". Sewage treatment methods can be divided into physical treatment methods, biological treatment methods, sludge treatment and chemical treatment methods generated by sewage treatment according to the type of water quality, and can also be divided into primary, secondary and tertiary treatment processes according to the degree of treatment .
Common problems and solutions of municipal sewage treatment
1. Urban sewage mainly comes from domestic sewage and proper industrial wastewater discharged from households, institutions, businesses, and urban public facilities. The amount of wastewater is large and there are obvious diurnal and seasonal periodic changes. The main pollutants in sewage are animal and vegetable oils, suspended matter, carbohydrates, proteins, surfactants, nitrogen and phosphorus compounds, microorganisms, etc. These organic pollutants in Inner Mongolia wastewater treatment are generally relatively easy to biodegrade and biochemical BOD / The COD value reaches 0.5 ~ 0.6, and contains nutrients such as nitrogen and phosphorus, which provides a good environment for growth. For a long time, the activated sludge method has been mostly used for the secondary biological treatment of urban domestic sewage. It is currently the most widely used secondary biological treatment process in various countries in the world. However, there are widespread infrastructure costs, high operating costs, high energy consumption, and complicated management. Problems such as sludge swelling and sludge floating are prone to occur, and inorganic nutrients such as nitrogen and phosphorus cannot be removed. Since sewage treatment is a project focusing on environmental and social benefits, it is often limited by funds in the process of construction and actual operation, making the problem of treatment technology and funds a "bottleneck" for water pollution treatment in China. At present, in the field of urban domestic sewage treatment research and application, the common problems are:
(1) The traditional activated sludge method is often used, with high capital construction and operating costs, high energy consumption, complicated management, and sludge swelling. Process equipment cannot meet the requirements of high efficiency and low consumption.
(2) With the continuous stricter sewage discharge standards, the requirements for the discharge of nitrogen, phosphorus and other nutrients in sewage are higher. The traditional sewage treatment processes with nitrogen and phosphorus removal functions in Inner Mongolia wastewater treatment are mostly activated sludge processes. Often, multiple anaerobic and aerobic reaction tanks need to be connected in series to form a multi-stage reaction tank. The purpose of denitrification and phosphorus removal is achieved by increasing the internal circulation. This will necessarily increase the cost and energy consumption of infrastructure investment, and make operation management More complicated.
(3) At present, the treatment of urban sewage is mostly concentrated. The investment in a huge sewage collection system far exceeds the investment in the sewage treatment plant itself. Therefore, a large sewage treatment plant is constructed to centrally treat domestic sewage and reuse it from sewage. In terms of perspective, it is not necessarily the only option.
(1) Multi-stage aerated biological filter is used instead of ordinary biological tank: forced aeration of biological aerated filter, sufficient oxygen supply, the volume load of Inner Mongolia sewage treatment aerated biological pool can reach 2 ~ 10kgCOD / m3.d, The processing capacity per unit volume is about 10 times that of ordinary biological filters. The specific surface area of the SNP filler added to the aerated biological filter is as high as 500 ~ 900m2 / m3, and the area available for biological growth in a unit volume is more than ten times that of the ordinary filter. The porosity is as high as 92% ~ 95%, the inert component only accounts for 4% ~ 8% of the pool capacity, and the effective space is more.
(2) Adding different filter materials, so that the anaerobic, anoxic and aerobic zones are simultaneously contained in the unit filler, which is conducive to the formation of the food chain, and can simultaneously remove nitrogen, phosphorus, and organic matter under aerated conditions. Features.
(3) Replacing the sedimentation tank in the traditional water treatment process with an air floatation tank can greatly improve the removal rate of the aging and falling off biological membranes and suspended matter of the aerated biological filter, which can reduce the hydraulic retention time, reduce the footprint of the structure, For civil construction investment, compared with the sedimentation method, the area of the air flotation method is only 1/8 ~ 1/2, and the tank volume is only 1/8 ~ 1/4. The water content of the scum discharged from the wastewater treatment in Inner Mongolia is greatly reduced, and the sludge volume is only 1/10 to 1/2, which is convenient for the further treatment and disposal of the sludge and saves the treatment costs.