Main characteristics of rural wastewater in China
chinagate.cn, April 20, 2015 Adjust font size:
A research report of Sino-Africa wastewater treatment cooperation was released by Beijing Municipal Research Institute of Environmental Protection and Tongji University, to explore the possible wasterwater treatment technology transfer mechanism between China and African countries.
Currently, it is widely believed that more than half of total wastewater discharge is from domestic wastewater in rural areas, which has become an important factor for water pollution in river basin in China.
Rural wastewater consists of black water and grey water. The former is domestic wastewater with high concentration from toilet flushing, while the latter is wastewater with low concentration from washing water in the kitchen, laundry and bathing. The wastewater contains contaminants of organic matter, nitrogen and phosphorus nutrients, suspended solids, bacteria, etc., with general concentration of:
COD - 250 to 400 mg / L; ammonia - 40 to 60 mg / L; TP - 2.5 to 5 mg / L.
The main characteristics are:
(1) The population size is small and it is widely scattered. Rural wastewater flow is usually less than 500m3/day. It is difficult to collect from low density rural settlements and scattered villages.
(2) There are many sources of rural wastewater. Besides human faeces and kitchen wastewater produced, there are wastewater from household cleaners and leachate produced from garbage.
(3) The quantity changes with time. Rural residents have similar life patterns with higher discharge during daytime and lower discharge in the morning and nightfall, and sometimes no discharge at night.
(4) The organic concentration of wastewater is generally high and biodegradability is relatively good. COD and BOD5 in the effluent are higher than that in urban wastewater, and the wastewater is also substantially free of toxic and hazardous pollutants with good biodegradability.
(5) Regional variations in water pollution are large and are mainly caused by differences in rural economic development level, production and lifestyle, geographical distribution and topography.
