Performance Evaluation of Sand Filter in Improvement of Effluent Wastewater from Gaza Wastewater Treatment Plant

Abstract

Sand filters in different types are considered tertiary treatment which have the ability to remove pollutants from effluent of secondary waste water treatment plants. In the period from August to December 2013, field and laboratory test were conducted to asses performance of sand filters in both types (planted and unplanted slow sand filter) in south of Al Zaytoun for its ability to remove pollutants such as biochemical oxygen demand BOD5, total suspended solid TSS, fecal coliform FC and Nitrogen. Results showed that Sand filters in both types (planted and unplanted slow sand filter) have the ability to remove biochemical oxygen demand(BOD5), chemical oxygen demand (COD), total suspended solid (TSS), fecal coliform (FC), and nitrogen compound. An interesting outcome of the study is that sand filter removed 71% of TSS, 52% BOD5, 32% COD, 93% FC, 39% TKN, 35%NH4 as result of NH3 conversion to NO3 . The study performed that there is similarity in efficiency of sand filters(planted and unplanted slow sand filter) this is due to monitoring period from the first period to reed (growth stage). There is decrease in efficiency to remove pollutants with time during 24hr. also by increase of infiltration rates. It can be concluded that application of sand filters will significantly improve the quality of treated waste water. The study revalued that increasing retention time in the sand filters considerably increased the removal efficiency.