Evaluation of Microbiological Quality of Desalinated Drinking Water at Gaza City Schools, Palestine

Abstract

Gaza strip has very limited water resources. Groundwater is the main source for domestic, industrial and agricultural purposes. Over abstraction of the groundwater had led to sea water intrusion which increases salinity of the groundwater by time. Water resources are deteriorating in terms of quantities and quality which led to the establishment of small business scale desalination plants to treat and distribute desalinated water by trucks for most of Gaza strip areas including schools. The aims of this research are to check if there is microbiological contamination at desalinated water at Gaza city schools, to determine the source of contamination if any, and to determine the difference between drinking water microbiological quality between schools moderated by Ministry of High Education (MOHE) and schools moderated by United Nations Relief and Works Agency (UNRWA). Some of 130 school buildings have been selected and the data evaluated for the periods from the school year 2008-2009 to 2010-2011. Results indicated a microbiological contamination in the desalination plants inlet and in schools water tanks. The microbiological safety of desalinated drinking water at Gaza city schools has improved in the last three school years (2008-2009 to 2010-2011). It is noticed that the weakness of monitoring program of desalinated drinking water leads to a higher contaminated schools ratio. The well maintenance of the desalination plant leads to keep the product of the plant safe and well accepted. When the inlet of the plant was contaminated the UV unit helped to kill the source of contamination, and the chlorination process insures the safety of the plant product. About 11.8% of Gaza city students noticed that there is no cover for the drinking tank, 28.6% of these students noticed birds standing on tank's upper hole, which may lead to a serious cause of animal source contamination. At school year 2010-2011, about 23.8% of monitored schools at East directorate were contaminated before follow-up process. Nearly 20.8% of monitored schools at West were contaminated. But 56.5% of monitored schools at UNRWA were contaminated. The believed reason of high contamination percent of UNRWA schools is that their monitoring program is new and need to be upgraded. Contaminated schools ratio has decreased after follow-up process, this enforces follow-up importance. Contaminated schools after follow-up were 19.0% at East, 15.1% at West. UNRWA did not apply follow-up process. At the same school year (2010-2011), disinfected schools percentage because of the follow-up process was 20.0% in East and 27.3% in the West.