Water Quality Characteristics Of Water Systems In Rural Area Under The Influence Of Urbanization

Village is the initial form of settlements and an important symbol of civilized society in the process of human evolution.Two phases ofancient urbanization and modern urbanization can be identified for this process.Urban and rural areas showed close communication and homogeneous characteristics and in ancient urbanization phase and can be obvious distinguished after modem urbanization from e industrial revolution.After the Reform and Opening up,the rural areas in urbanized and semi-urbanized areas have developed rapidly,and characteristics of urbanized and semi-urbanized areas has gradually converged,while the rural development in non-urbanized areas shows more obvious gaps with urban areas.On the other side,similar to urbanized are,non-urbanized rural areas also facing serious ecological problems,such as water pollution caused by the overloading of toilet flushing,Overuse of fertilizer and pesticides for the lack of labor force,and the introduction of new pollutants caused by the use of new materials.With the release of Rural Revitalization Strategy by government,the improvement of rural environment and infrastructure has become an urgent problem in rural planning.Hollowing out and Aging has become the obvious characteristics for villages after urbanization,the mechanisn on how to influence the water quality of villages and its requirement for infrastructure has become an urgent problem to be solved.In this study,three villages with three typical water systems were selected as study models.Ammonia nitrogen,chemical oxygen demand(COD)and anionic detergent concentration(LAS)are selected as key impact factors for water quality transfer.The results show that in traditional Beitang system,soil infiltration can effectively remove ammonia nitrogen,general organic matter and anionic detergent,thus ensuring the safety of water supply.The ravine stream system has potential of dilution and self-purification and protection or site selecting of source water could ensures the safety of water supplyUsing 152 kinds of Pharmaceutical and Personal Care Products(PPCPs)to indicate living activity and 97 kinds of pesticides and 262 kinds of typical chemicals to indicate industrial production activity,water samples collected during ordinary low populated time and festival high populated time are analyzed for emerging contaminants above-mentioned.The results show that the barrier effect of the traditional Beitang system on emerging contaminants is not sufficient and risk of concentration,amplification of emerging contaminants can be recognized,and the system is highly sensitive to the increase of population density.The results from ravine stream systems shows more stability,but the removal of emerging contaminants by stream self-purification is low.Risk of exceeding environmental capacity at the point of downstream can be recognized.To ensure the safety of water supply,the standard of rural water supply and drainage infrastructure should be revised to strengthen water safety barrier under the background of urbanization.In villages characterized by hollowing and aging in non-urbanized areas,the natural barrier of traditional water system can ensure the water quality and safety by reasonably choosing and protecting water sources.However,villages with condition ofr rapid economic progress should establish higher requirements for water-related infrastructure.In villages with Beitang systems,water treatment process should be improve to remove emerging contaminants and in villages with stream systems,water source protection is much more important than final treatment,and sewage treatment system should be further improved to avoid exceeding the self-purification capacity of the stream system.