Removal of suspended solids using in-situ filtration in surface water

Compromised water quality impacts many surface water resources worldwide. The decline in the water quality can be attributed to various pollutants discharged into water areas such as rivers, lakes and ponds. Most of the pollutants, such as nutrients, organic compounds, bacteria, which were released into the water areas, are adsorbed onto the surface of the suspended solids (SS) and settle to the bottom. Phosphorus (P) is considered as the controlling element in the propagation of eutrophication in water bodies. Algal blooms threaten lake water quality and in order to control their growth, removal of P along with the SS is essential. The focus of this study was to improve water quality by removing SS and phosphorus through a pilot scale in-situ filtration tests. A nonwoven geotextile was used as the filter medium. The pilot-scale unit was set up at Lac Caron, located 75 km north of Montreal in Saint-Anne-des-Lacs, Quebec, Canada. Filtration tests using four different nonwoven filters were performed. A nonwoven filter with apparent opening size (AOS) of 150 om and thickness of 0.3 cm was effective in removing SS concentration by 91%. The water quality improved in terms of SS and P removal rendering in-situ filtration as an effective treatment system or remediation technology for contaminated surface water bodies such as inlets, bays, lakes, and ponds.