In situ removal of contaminated suspended solids from a pond by filtration

Suspended solids (SS) which have been discharged into ponds, lakes, and enclosed sea areas from shores and rivers absorb various substances such as heavy metals and nutrients. In this study, a small upward filtration system was developed to remove contaminated SS from the water. The system consisted of a main body with a flotation device, three pumps, two float sensors, solar panels and batteries. The filter medium consisted of a nonwoven geotextile with a thickness of 5 mm. The pilot experiment was carried out in Shimizu Utozaka pond in Japan. SS, chemical oxygen demand (COD) and total phosphorus (T-P) removal efficiencies of 88.5%, 56.5% and 64.2% were obtained, respectively. In addition, the estimation of pollutant removal was determined from the amount of removed SS. This calculation enables not only the design of filtration systems for future individual cases, but also quantitative evaluation for the effect of restoration.