1. Rural domestic sewage characteristics
1.1 Water quality characteristics
① The distribution of sewage is scattered, involving a wide range and strong randomness, and it is very difficult to prevent and control. The pipe network collection system is not complete, extensive discharge, and basically no sewage treatment facilities. ② The concentration of rural sewage is low and the changes are large. ③ Most of the rural life The nature of the sewage is not much different, the water quality fluctuates greatly, and the biodegradability is strong; ④ the sewage quality of the sewage discharged from the toilet is relatively poor, but it can enter the septic tank to be used as fertilizer.
1.2 Water volume characteristics
① Generally, the amount of domestic sewage in rural areas is relatively small. Except for small towns, the general rural population lives scattered, the amount of water is relatively small, and the amount of domestic sewage generated is also small; ② The coefficient of change is large, and the residents' living laws are similar, which leads to rural domestic sewage The discharge is greater in the morning and evening than in the daytime, and the drainage volume at night is small, and may even be cut off, and the water volume changes significantly.
2. Several treatment technologies for rural domestic sewage
2.1 Domestic sewage purification biogas digester treatment
Domestic sewage purification biogas digester treatment technology can adapt to domestic sewage treatment in rural areas, and has a frugal treatment method that can reflect the combination of environmental and social benefits. Biogas digesters produce biogas by anaerobic fermentation of organic matter in sewage. Humans use biogas for cooking, power generation, etc. for recycling. The treated domestic sewage removes most of the organic matter, purifies it, and then discharges it. The treated water can be used for watering flowers or as a fountain. The domestic sewage purification biogas digester has replaced the traditional septic tank. At present, the technology of domestic sewage purification biogas digester has been greatly improved, the technical perfection is relatively shaped, and the level of rural domestic sewage treatment will be improved.
2.2 Land infiltration treatment system treatment
The technology of land infiltration treatment is to use the automatic purification ability of nature to absorb the organic matter in the sewage through the soil layer or vegetation using physical, chemical, biological and other effects to reuse the organic matter in the sewage to make the vegetation grow more flourish Degradation of organic matter in sewage.
In the process of sewage treatment, the effect of nature is often used for filtering, and the organic matter in the sewage is degraded and separated, which is suitable for the treatment of rural domestic sewage.
2.3 Artificial wetland treatment system
Constructed wetland is a technology constructed to mimic natural wetland systems to treat rural domestic sewage. The structure that was created was filled with sewage at the bottom according to a certain technical plan. These fillers include stones, sand, etc. Plants that are adapted to the living conditions of domestic sewage are planted on this surface, and the treatment and purification of pollutants are achieved through the synergistic action of microorganisms or plants in the ecosystem. Constructed wetlands are economical and practical, suitable for treating rural sewage. The mechanism it uses is relatively complex, and the purification of vegetation plays an important role. This wastewater treatment technology has been widely used and is more suitable for rural areas.
2.4 Biological filter technology
The biological filter has a filler made of crushed stone and plastic products, and the microorganisms attach to the filler and grow into a biological community. When the sewage enters the biological filter, a reactor is formed instantly to decompose the organic matter in the sewage. The filler traps large particles and suspended matter in the filtered sewage, and functions as a filter pond. The microorganisms in the filtration tank can hydrolyze and convert large molecules of insoluble matter into small molecules of soluble matter, and play a role in hydrolysis. The microorganisms in the process pool absorb and absorb organic pollutants in the water, part of them are converted into their own growth, reproduction and metabolism, and part of them are decomposed to produce biogas and discharged.
2.5 Solar / wind energy micropower wastewater treatment technology
The solar / wind energy micropower wastewater treatment technology is based on the traditional "A2 / O" process, and consists of solar photovoltaic panels, small wind turbines, battery packs, aeration systems, return systems, microcomputer control systems, and telecommunications systems. Solar photovoltaic panels convert solar energy into electricity, combined with small wind turbines to generate power for aeration facilities and return facilities, and the excess energy is stored in the battery; according to the optimized and debugged data, the microcomputer control system is used to complete automatic control , Automatic operation of aeration facilities, reflux facilities and mixing facilities. It has been treated with standing water, anaerobic biological treatment, contact oxidation, and precipitation, so as to meet the standard discharge.
Solar energy and wind energy are used as energy resources in sewage treatment applications, not only for micro-power energy sources, but also in the north, they can also serve as thermal insulation for pools and improve winter sewage treatment efficiency. The sewage treatment technology has the advantages of cleanness, convenience, safety, energy saving and the like. The solar / wind energy micro-power sewage treatment technology rationally utilizes heat and climatic conditions to make the whole process more environmentally friendly and energy efficient; its operating cost is zero, which is incomparable with other treatment processes. However, it also has certain shortcomings. It lacks professional technical personnel and has difficulties in the later operation and maintenance.
The treatment technology of rural domestic sewage should be based on the geographical status of the rural areas, and fully consider the local rural climate, temperature, humidity and other conditions for the implementation and management of sewage technology. Use domestic sewage purification biogas digester, land infiltration treatment system, artificial wetland treatment system, biological filter, solar / wind energy micro-power sewage treatment and other technical methods to select the corresponding treatment technology for the status of rural sewage, and introduce it to local conditions Suitable for wastewater treatment technology in the area.