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The urban environment of every city of Pakistan has been degraded because of open dumping and burning of organic wastes along with other wastes. The focus of this study was to evaluate the fruit and vegetable wastes for methane generation through biomethanation process. After collection, various parameters such as alkalinity, volatile fatty acids, pH, lignin content, moisture content, total solids, volatile solids, fixed carbon, and elements (C, H, N, O, S) of waste samples were determined by using standard methodology. Anaerobic biodegradability of fruit and vegetable wastes was observed from 54 to 77% and from 59 to 87% along with their methane generation potential in the range of 258-367 NmL /gmVS and 274-407 NmL/gmVS, respectively. Further, the effect of feedstock to inoculum ratio was studied. The result of that showed that lower methane potential at a higher ratio and vice versa was observed. It was concluded that at a lower feedstock to inoculum ratio, fruit as well as vegetable wastes become more feasible for the biomethanation process. The study recommends that the conversion of fruit and vegetable wastes into methane gas by anaerobic digestion plays a significant role to save urban environment of the country.

In this study an effect of acidic pre-treatment on the CS (Canola Straw) and BD (Buffalo Dung) by anaerobic co-digestion was investigated. H2O2 (Hydrogen Peroxide) is a mainly accustomed reagent, used as a bleaching agent in the different industries such as paper and wood. In the present study, it was used as a pre-treatment chemical at varying concentrations in batch reactors. The co-digestion of CS and BD was carried out in SAMPTS (Semi-Automatic Methane Potential Test System) at mesophilic (37±1oC) conditions. The CS was pretreated in glass bottles with different concentrations of the H2O2 for seven days. The inoculum used in the present study was an effluent of the CSTR (Continuous Stirred Tank Reactor), which was treating BD at mesophilic conditions. The specific methane production from the codigestion of canola straw and BD, by the pre-treatment of H2O2 at concentrations of 0.5, 1.0, and 1.5% were 530.8, 544.5, and 510.3 NmL CH4 g/VS, respectively. The significant reduction in the volatile solids of CS was observed at the optimum pre-treatment of 1.0% H2O2.

The SRRMs (Steel Re-Rolling Mills) are being releasing air pollutants in the environment. In order to evaluate their effect on the health of the workers, health and safety issues were analyzed by first measuring the concentrations of SO x (OIxides of Sulphur), NO x (Oxides of Nitrogen), CO (Carbon Monoxide) and O2 (Oxygen) produced in the three SRRMs located in SITE area Hyderabad. The mean concentration of SO x , NO x and CO were in the order of 0.35, 0.280, 6.333 ppm, respectively, whereas the mean concentration of O 2 was 203.53 thousand ppm. As per results, the concentration ofair pollutants, including SOx and NO x were significantly higher than to the NEQS (National Environmental Quality Standards) and NAAQS (National Ambient Air Quality Standards). The concentration ofCO was lower than to the NAAQS, but higher than to the NEQs, while the concentration of O2 was slightly lower than to the standard value. The workers who were exposed to these air pollutants are being suffering from chronic diseases related to breathing and allergies. Moreover, labour staff was lifting heavy loads manually, which causes them to muscular and joint problems. In all the SRRMs under study, the electrical and mechanical equipments were used without any safety. The MSDS were not displayed on the workstations, the housekeeping was inadequate and most of the workers were performing their jobs without personal protective equipment. In addition to these, the other serious issues related to the occupational health and safety were an unhygienic supply of water, higher noise level, placement of explosive cylinders in the open atmosphere and unavailability of the first aid facilities in the Mill premises.