In-situ treatment of micro-polluted water supply in natural wells of karst areas

In the regions of Southwest China, natural karstic wells are the main sources for local water supplies in a distributed manner. In this paper, a study on the technical principle of water treatment for some representative karst wells in the karst areas was conducted, based on the analysis of the well water pollution characteristics. The objective of this study is to provide treatment measures for preventing the water from pollutions by any means. In combination of the technical principle with a pilot test, this paper presents in detail the idea for the design and associated design parameters, the technics of water treatment and the matters need attentions during the construction of rapid infiltration tank. Moreover, results of the test showed that, after the treatment of the contaminated well water, its turbidity was less than 5 degrees; the removal rate of trace organic matters reached more than 35%; the ammonia, nitrite and nitrate levels were reduced by more than 60%; and the maximum rate of bacteria removal reached 95% as well. The rapid infiltration technology applied in the water treatment does not require additional chemical agent, thus avoiding any possible adverse effect and hygienic problem arose from the use of coagulant and sterilant. The water quality of the treated natural karstic wells was hence improved, which generally meets the requirements of the national drinking water standards.