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This study presented performance data on a low cost and easy maintenance pilot system for on-site treatment and reuse of water collected from wash sinks and fountains, as major sources of greywater (GW) at schools. Various treatment options were studied including screening, sand filtration, chlorination, and UV disinfection operated at different flow rates. Results showed that filtration operated at low rates is very effective in total suspended solids (TSS) removal, while UV proved to be more effective than chlorination for reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total coliforms. Removal efficiencies up to 63%, 30% and 20% were obtained for TSS, COD and BOD, respectively and reductions of log TC (CFU/100 ml) from 6.5 to 2 were obtained at a filtration rate of 14 m/d·m. Treated effluent satisfied WHO standards for reclaimed water reuse in landscape irrigation and toilet flushing. The filtration-UV system is robust, showing the best and most reliable performance for low and high strength GW treatment even under a 10-fold increase in flow rate. A 5 m/d pilot plant was developed for schools having 500 students and detailed cost-benefit analysis indicated a net saving value, a surplus of $1,600 per year, and pay back after 6 years and 11 months.

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In Kuwait, oil wells exploded in 1991 have created numerous massive oil lakes, which have subsequently dried and contaminated the soil. A research project was initiated to delineate the type and extent of contaminated soil using an area survey method, namely Electrical Resistivity Topography (ERT), to examine dry oil lakes located in Bahra, Subiya. The specific objective was to assess the applicability of the environmentally friendly ERT to assist in the design of measures to remediate the contaminated land. ERT results were generated by testing a grid in both contaminated and non-contaminated areas. In addition, conventional soil boreholes were used to explore the sub-surface profile and depth of contamination in these areas for comparison with ERT results. In-situ and laboratory physical and chemical tests were performed on soil samples collected from the site to identify the contamination type and concentration as well as variation in the physical properties of the soil profile with depth. Results indicated the contamination depth to be 1.2 m from the ground surface. These results were also confirmed by borehole analyses (chemical and physical). Chemical tests indicated that the contamination consists of hydrocarbons. The findings demonstrate that ERT can be used to establish a baseline in the assessment of potential hydrocarbon-contaminated sites and is applicable for determining the type and depth of contamination without the need for expensive and tedious boreholes and in-situ and laboratory soil testing.