Ali Riahi

NOVEL CONFIGURATIONS OF SOLAR DISTILLATION SYSTEM FOR POTABLE WATER PRODUCTION

More and more surface water are polluted with toxic chemicals. Alternatively brackish and saline water are used as feed water to water treatment plants. Expensive desalination process via reverse osmosis or distillation is used in the plants. Thus, this conventional desalination is not suitable for low and medium income countries. A cheaper method is by solar distillation. However the rate of water production by this method is generally considered low. This research attempts to enhance water production of solar distillation by optimizing solar capture, evaporation and condensation processes. Solar radiation data was captured in several days in Perak, Malaysia. Three kinds of experiments were done by fabricating triangular solar distillation systems. First type was conventional solar still, second type was combined with 50 Watt solar photovoltaic panel and 40 Watt Dc heater, while third type was integrated with 12 Volt Solar battery and 40 Watt Dc heater. The present investigation showed that the productivity of second and third systems were 150% and 480% of the conventional still type, respectively. The finding of this research can be expected to have wide application in water supply particularly in areas where fresh surface water is limited.

Experimental Investigation on the Performance of Four Types of Solar Stills in Malaysia

This study aims at improving a solar distillation still by comparing the performance of four types of double slope single basin solar stills to produce adequate amount of potable water in the areas with confined fresh water. These solar stills fabricated with similar shapes. In each solar still a stainless steel basin with the length of 50 cm, width of 30 cm and depth of 8 cm was utilized. The still configurations differed based on inclusion of 2 cm depth of sea sand layer in the basin, a layer of black paint in the basin and use of a 50 W PV-DC heater. The study was conducted to increase the potable water production under Malaysia tropical condition. A comparative research of cumulative water production among these solar stills showed that solar still with black painted basin was the more efficient; producing 234 %, 190% and 148% the potable water produced by a conventional solar still, solar still with sand layer in basin and solar still connected to a PV-DC heater, respectively.

The Performance of Trapezoidal Glass Cover Solar still during Monsoon Period of Tropical Environment

Seawater or brackish water desalination process using Reverse Osmosis as one of the current treatment technologies is expensive. A cheaper alternative is by using solar still. The paper presented the performance of solar still under tropical environment during monsoon period. The solar still was constructed using black stainless steel basin. Measurement of temperatures, solar intensities and distillate produce were recorded in the month of November and December, 2013, between 8 am and 6 pm. It was found that the distillate production rates obtained varied from 1.88 kg/m2/d to 2.26 kg/m2/d with efficiency of 37.7 %.

Evaluation of Leachate Characteristics from Different Leachate Ponds in a Semi-Aerobic Landfill

In this study, the performance of a semi-aerobic landfill was monitored through the analysis of leachate composition collected from different leachate ponds; collection pump (CP), equalization pond (EQ) and aerated pond (AP). The landfill site is located in the tropical environment of the central region of Malaysia. Twenty parameters were analyzed and the average values of the parameters for leachate at the CP, EQ and AP, which include; pH (8.24, 8.00 and 8.73), total kjeldahl nitrogen (3987.25, 8744.6, 1927.31 TKN-N), ammonia-N (3726, 3800, 1560 mg/L NH3-N), nitrate (26.7, 33.3, 25 mg/L NO3-N), total phosphorus (0.85, 0.78, 0.92 mg/L PO43-), BOD5 (305, 311.3, 201 mg/L), COD (16100, 14587, 12780 mg/L), BOD5/COD (0.019, 0.021, 0.016), turbidity (405, 735, 940 NTU), colour (3991, 4122, 3412 Pt Co), TSS (109.3, 58, 50.7 mg/L), EC (32.8, 21.9, 37.0 mS/cm) and TDS (21.98, 14.7, 24.8 mg/L) were recorded appropriately. The results realized from the analysis of the three ponds, were compared with previously published data and also the standards specified by the Malaysia Environmental Quality Act 1974. The obtained results indicate that the leachate from the aerated pond could remove some of the pollutants and was more stabilized when compared with the leachate from the pump and equalization ponds. It is also found that the aeration process in aerated pond could enhance the reduction of pollutants in the leachate. The measured leachates would require appropriate treatment methods in order to reduce the pollutants to meet the discharge standard before releasing them into water courses.

Drinking Water Production Using Passive Solar Stills with Different Absorbing Materials

Solar stills as the cheapest options used to desalinate brackish water in areas having freshwater availability limitation. The purpose of this work is to investigate the water production improvement of double slope solar stills using heat absorption materials in the basin. Three similar shapes double slope passive solar stills were constructed to conduct the experiments in tropical climate of Malaysia. Each solar still had a stainless steel trough and a transparent polythene film as basin and cover respectively. Three basins each having 50 cm length, 30 cm width and 8 cm depth were used to keep the fed lake water. 2 cm depths of black soil and sea sand were added in two solar still basins respectively, while the last solar still had only stainless steel trough as basin. Experimental investigations on the solar stills performance showed that the solar still with black soil had a highest output as compared to the solar still yield using sea sand layer in basin or conventional solar still using only stainless steel basin respectively. Some water quality parameters of lake water and produced distilled water were also tested in the laboratory and indicated that the treated water met the WHO standard for drinking.