Production of biologically stable water through process performance enhancement of Jericho Water Treatment Plant in Palestine.

Abstract

Since the establishment of Jericho Water Treatment Plant (JWTP) in 1956, around 500 m3 of drinking water per day are produced for more than 5000 inhabitants living in Aqbat-Jabr. Water spring at Wadi-qilt is considered the main raw water supply for the JWTP. It is operating fairly in summertime under poor management and lack of maintenance. The present treatment process entails slow sand filtration and disinfection processes. In rainy days the influent fecal coliforms are about 800 colonies/100 ml, which are significantly above those recommended by the WHO. The turbidity is more than 30 NTU; extensive growth of algae in feeding open canal and in the slow sand filters is visible. The water of Wadi-Qilt springs is polluted while flowing in the open canal more than 13 km long to JWTP. From 1997-1999, a few incidents of water born diseases were reported as a result of inadequate filtration and interruption of the process of the disinfection. JWTP is the only source of drinking water for Aqbt-Jabr, but failure of the treatment process at JWTP in wintertime forces the people of Aqbt-Jabr to use another water supply from an Israeli water company (MEKORT). The supplied quantity of water by MEKOROT is insufficient also it is more expensive than the water supplied by JWTP. Therefore the major objective of this paper is to identify pollution sources and provide protective measures for establishing a water treatment system which will produce a biologically stable treated effluent, especially during winter season. Physico-chemical and biological analysis on raw water at different sampling station of Wadi Quilt and treated water of JWT were conducted. A small pilot scale sand filter with a settling tank was constructed to simulate the present unit operations of JWTP. The analytical results conducted on the experimental SSF model suggest that the existing unit operations of the water treatment must be preceded by a settling tank with pre-chlorination unit. After executing the modifications on the experimental SSF model, the efficiency of removing turbidity has reached 85%, no algae growth was observed and no fecal coliforms were detected.