An experimental stuty on in-situ nitrate-contaminated remediation of karst water

The extremely inhomogeneous nature of karst aquifers make the cyclic movement of karst water controlled by structure, fissure space and development direction. Due to the complex environmental conditions, it is difficult to carry out in-situ remediation of karst water pollution. Up to now, there is no report on this issue in China. This work chose the typical karst development and nitrate-contaminated areas in central and southern mountainous area of Shandong province to construct a pilot project by drilling holes. The in-situ nitrate-contaminated karst water remediation tests were carried out by using the approach of“ethanol + glucose” liquid carbon source and the “polyvinyl alcohol + starch granule” solid-state reactor. The results show that: (1) the degradation rates of nitrate concentration in the denitrification solution of “ethanol + glucose” with concentration of 500 mg?L-1 and 1,000 mg?L-1 are 6.45% and 21.52%, respectively. (2)When denitrifying solid-state reactor of “polyvinyl alcohol 3 kg + starch granule 3 kg” and “polyvinyl alcohol 2 kg + starch granule 4 kg” with unit length component materials was used to denitrify the nitrate concentration, the degradation rates are 33.91% and 34.96%, respectively. The test proves that it is feasible and effective to adopt the in-situ remediation technology of groundwater pollution by using the hole group scheme in karst areas, which can achieve remarkable results. The layout of the remediation project and the test results of this work have certain reference significance for the in-situ remediation of karst groundwater pollution in similar areas.