Discussion on the application of rural sewage treatment technology in different regions of China

In the south of China, there are many mountains and hills and dense river networks. The technology of land infiltration and constructed wetland may be restricted by the existing rural terrain and slope. Therefore, in the selection of distributed sewage treatment technology, rural areas in southern China are suitable to consider the existing terrain factors and develop integrated composite processes of constructed wetlands, stabilization ponds, septic tanks, biogas digesters, anaerobic biological treatment and other technical units. For example, constructed wetlands in mountainous areas of Hubei province combine the composite treatment processes of anaerobic and drop water contact oxidation. Anaerobic biological treatment + constructed wetland + oxidized pond complex engineering facilities in Yunnan Dianchi Basin countryside.

Centralized processing technology

The commonly used centralized treatment technologies of rural sewage include activated sludge method, oxidation ditch method, biological contact oxidation method, sequencing batch activated sludge method (SBR), membrane bioreactor method (MBR), and large-scale constructed wetland method. According to the survey of the preparation team of the "Technical Guide for the construction and investment of Rural domestic sewage treatment Projects", the treatment scale of China's rural centralized sewage treatment facilities is generally below 500m3/d, and most of the facilities serve a village population of less than 5,000 people. The treatment scale of centralized sewage treatment facilities varies greatly, and centralized treatment technology can be selected when the general daily treatment capacity exceeds 20t, and the treatment capacity can reach up to 2500t/d. SBR, MBR and other new technologies occupy a small area, easy operation and management, high removal efficiency and do not require the construction of supporting sedimentation tank, is a more promising rural sewage treatment technology, but the current investment and construction cost is still high.

Comparison of centralized treatment techniques for rural domestic sewage

The construction of centralized sewage treatment facilities has been explored for a long time in the rural areas with high economic development level such as Northeast, North and southeast of China. The winter temperature in Northeast China is low, so it is suitable to adopt improved biological treatment, ecological treatment and multiple composite processes for the high cold climate. For example, a rural area in Heilongjiang Province adopted the composite technology of biological contact oxidation and double-layer subsurface flow constructed wetland to successfully cope with the extreme temperature up to -35℃. In North China and Northwest China, it is suitable to use the centralized treatment technology with constructed wetlands as the core, and appropriately add the unpowered anaerobic filter which is relatively simple to maintain for pretreatment. The water resources in South China are abundant, and the amount of domestic sewage produced by rural residents is large. For areas with better economic conditions, SBR, MBR and other technologies with less land area and higher treatment efficiency can be appropriately used. In general, the southern rural areas are suitable for the use of biological + ecological treatment processes, such as the combination of biological contact oxidation and constructed wetlands. For villages built near mountains and rivers, if there is a pond near the village, it can also be transformed into a constructed wetland system on the spot.

Neutral inorganic mineral coagulant water purification agent for small integrated water treatment equipment:

Luteng ecological mineral water purification agent is based on montmorillonite and other mineral clay as the main raw material, pure natural mineral components, non-toxic to the human environment and fish in water, the dosage of only about 1/3 of the general flocculant. Cost saving, capital investment is small, there is no need to build a large sewage treatment plant, the water quality after treatment can reach an amazing level 1 transparency, the treatment speed is fast, and the addition of agents only takes tens of seconds to make the sludge water separation reach the discharge standard. Because of the short sewage treatment time, it can greatly improve the efficiency of waste water recycling.

The treated water can be used for:

1. Farmland irrigation, afforestation and seedling cultivation;

2, urban miscellaneous water, including greening, toilet flushing, road flushing, building construction, vehicle flushing, fire fighting, etc.;

3, industrial water, including cooling, washing, boiler, process, product water;

4, environmental water, including recreational landscape water, ornamental landscape water, wetland environmental water;

5. Supplement source water, including surface water and groundwater

Scope of application

Lakes, ponds, rivers and other static or slow flow rate of turbid green algae water bodies, urban and rural domestic and industrial sewage, oily wastewater.