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The current study describes the desalination of sea water using solar energy with particular focus on the design and fabrication aspects for single slope solar still. The purpose of this study was to present a novel, economically feasible methodology along with the equipment to overcome the water shortage particularly in the remote areas along the coastal belt in Pakistan. In order to achieve these objectives, a laboratory scale solar still was fabricated made of galvanized iron having basin area of 5490 cm 2 (length of 90 cm and width of 61 cm), front height 15 cm and back height 32 cm. The Inclined angle was kept at 15 o . The experiments were conducted during typical winter days. Results showed that when the highest ambient temperature was 29.9 °C, the maximum value of the average solar intensity was 1,080 W/m 2 . A remarkable decrease in terms of total suspended solids (TSS), total dissolved solids (TDS), thermal conductivity, hardness, turbidity, and pH was observed. The value of TDS decreased from 29,100 mg/L to 385 mg/L, TSS from 0.07 g/100mL to 0.00086 g/mL, thermal conductivity from 45,500 μs to 595μs, hardness 133 meq/L to 2.7 meq/L, turbidity from 29.3 NTU to 19.3 NTU, and pH from 9.36 to 6.22, respectively. Furthermore, temperature profile against the intensity was drawn to identify the peak efficient hours with highest heat intensity. The suggested technique cannot only give a solution for the domestic level use rather it can be utilized in commercial scale in solar desalination facilities.

Heavy metals in municipal wastewater are of utmost concern for researchers and environmental agencies due to their adverse effect to the ecosystem. Various technologies were practiced for the removal of heavy metals; however, adsorption is one the most interesting technique for its low cost, simple operation and reasonable efficiency. In this study, removal of Zinc (II) from municipal wastewater in Quetta city of Pakistan was investigated by using activated carbon (AC) developed from Rice Husk (RH) and Kikar Charcoal (KC). Char were made by heating KC and RH in a tubular reactor at 700 o C under N2 gas flow. Furthermore, Char material obtained were activated using H2SO4 as an activating agent to increase the surface area and porosity of the char materials. The biochar adsorbents were characterized using SEM, EDX and BET techniques. To identify the efficiency of adsorbents, the wastewater samples collected from Shahbaz town area of Quetta city were treated using different particle size of AC (180 and 300 µm) and varying adsorbate dose (0.1, 0.2, 0.3, 0.4, 0.5, 0.6 and 0.7 g/50 mL), pH of the solution (3, 4, 5, 6, 7), respectively. The results showed that increase in the mass of adsorbents had a direct relation with the removal efficiency of Zn(II). The maximum removal efficiency for zinc (II) was found to be 99 % and 72.34 % for KC and RH based ACs at adsorbent dose 0.7 g/50mL and pH 6, respectively. A small difference has been observed between the efficiencies of both ACs this was due to the difference between their surface area and porosity. While studying isotherm models the data was best fit with Langmuir isotherm model. The amount of zinc in the treated wastewater was recorded well enough under the standard limits provided by Environmental protection agency (EPA). This technique of treating municipal wastewater by using inexpensive biomass as adsorbent found to be very efficient and environmental friendly.

Waste biomass is gaining increased interest as a feedstock for energetic and non-energetic products. In this study, potential of wasted mango seed shell for bioenergy production by using laboratory scale updraft gasifier was investigated. Gasifier was operated with and without packing at air velocity of 3.0 and 3.5 m/s. Biomass characteristics, temperature profile, influence of air velocity on higher heating value (HHV) of producer gas, composition of gas and thermal efficiency of gasifier were parameters considered for analysis. Operation without packing material showed better performance. Results depict that maximum 3.56 MJ/Nm 3 of producer gas was generated at lower air velocity. Maximum operating time for complete consumption of biomass was recorded as 165 minutes. Negligible difference found in temperature profile between both operating modes. Temperature profile indicated that temperature attained during operation was 372°C, 742 °C, 604 °C and 423 °C for drying, combustion, reduction and pyrolysis zone, respectively. The Proportion of product gas was 75 %, while black thick liquid (mixture of Tar and moisture) and biochar were byproducts contributed about 8% and 10%, respectively. Mango pit shell waste is valuable bioenergy feedstock and its recycling could be economically and environmentally beneficial for mango processing industry.