Development of filtration system for removal of contaminated suspended solids in an enclosed sea area

The quality of seawater can be improved by removing suspended solids (SS) that may adsorb hazardous substances, such as heavy metals, polycyclic aromatic hydrocarbons, bacteria, etc. In this study, two types of filtration systems are developed in order to remove SS from sea, lake, and pond water. The first filtration system is a larger system for the rapid reduction of SS, and the other can be used for a slower removal of SS. The features of the smaller system are that solar panels were used as the power source and clogging of the filter can be prevented by a reverse water flow with an automatic control. Long-term in situ experiments showed that SS were almost completely removed by filters made of granular materials. Removal capacity was dependent primarily on both the sectional area of the filter and the relationship between the permeability of filter materials and the size of the SS. With treatment, good water quality was obtained in terms of SS, chemical oxygen demand and concentrations of nutrients.