A magic of nature.Waters under 10 meters of riverbeds of Wu River and Maoluo River was analyzed by National Yunlin University of Science & Technology. Base on a paper “Waterheads’ Exploration, Tests and Analysis in Kuai-kuan Water Treatment Plant” from Taiwan Water Corporation, the pollutants in water from Wu River filtered through gravel was diluted to safety value, including amines, ammonium, E. coli, and so on.
Marvellously, the quantities of heavy metals decreased after they were dealed with messy gravel. For example, the concentration of manganese in Maoluo River was 1.23mg/L, beyond the underwater-examining standard, but it was under 0.04mg/L in wells, even lower than the detection limit; the quality was improved by up to 96％. And the heavy metal arsenic was similarly. The average concentration was up to 1.31mg/L in Wu River and Maulou River, but was much smaller than 0.001mg/L; farther more, arsenic couldn’t be detected in two wells. What’s more, the river contained 0.003mg/L selenium, but we couldn’t detect it in wells.
Source:http://eem.pcc.gov.tw