The organochlorines (OClPs) and organophosphates (OPPs) pesticides in surface and ground water having intensive agriculture activity were investigated to evaluate their potential pollution and risks on human health. As per USEPA 8081 B method, liquid-liquid extraction followed by Gas-Chromatographic technique with electron capture detector and mass selective detector (GC-MS) were used for monitoring of pesticides. Among organochlorines, α,β,γ,δ HCH’s, aldrin, dicofol, DDT and its derivatives, α,β endosulphan’s and endosulphan-sulphate were analysed; dichlorovos, ethion, parathion-methyl, phorate, chlorpyrifos and profenofos were determined among organophosphates.As compared to ground water, higher concentrations of OClPs and OPPs were found in surface water. Throughout the monitoring study, α - HCH (0.39 μg/L in Amravati region),α - endosulphan (0.78 μg/L in Yavatmal region), chlorpyrifos (0.25 μg/L in Bhandara region) and parathion-methyl (0.09 μg/L in Amravati region) are frequently found pesticide in ground water, whereas α,β,γ-HCH (0.39 μg/L in Amravati region), α,β - endosulphan (0.42 μg/L in Amravati region), dichlorovos (0.25 μg/L in Yavatmal region), parathion-methyl (0.42 μg/L in Bhandara region), phorate (0.33 μg/L in Yavatmal region) were found in surface water.Surface water was found to be more contaminated than ground water with more number of and more concentrated pesticides. Among pesticides water samples are found to be more contaminated by organophosphate than organochlorine. Pesticides in the surface water samples from Bhandara and Yavatmal region exceeded the EU (European Union) limit of 1.0 μg/L (sum of pesticide levels in surface water) but were within the WHO guidelines for individual pesticides.

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In the present study, solar photocatalytic oxidation has been investigated through laboratory experiments as an alternative to conventional secondary treatment for the organic content reduction of high COD wastewater. Experiments have been performed on synthetic high COD wastewater for solar photocatalytic oxidation using a parabolic trough reactor. Parameters affecting the oxidation of organics have been investigated.The experimental design followed the sequence of dark adsorption studies of organics, followed by photolytic studies (in absence of catalyst) and finally photocatalytic studies in presence and absence of additional oxidant (H2O2). All the experimental studies have been performed at pH values of 2, 4, 6,8,10 and the initial pH value of the wastewater (normal pH). For photocatalytic studies, TiO2 has been used as a photocatalyst. Optimization of catalyst dose, pH and H2O2 concentration has been done. Maximum reduction of organic content was observed at the normal pH value of the wastewater (pH = 6.8). The reaction rate was significantly enhanced in presence of hydrogen peroxide. The optimum pH other than the Normal was in the alkaline range. Acidic pH was not found to be favourable for organic content reduction. pH was found to be a dominant factor affecting reaction rate even in presence of H2O2 as an additional oxidant. Also, the solar detoxification process was effective in treating a waste with a COD level of more than 7500 mg/L, which is a otherwise a difficult waste to treat. It can therefore be used as a treatment step in the high organic wastewater treatment during the primary stage also as it effectively reduces the COD content by 86%.

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Photo-chemical-transformations of organophosphate pesticides, chlorpyrifos, dimethoate and phorate, using advanced oxidation processes (AOPs) namely UV photolysis, UV/H 2 O 2 , UV/Fenton and Fenton systems in aqueous solution were investigated in this work. A laboratory set-up was designed to evaluate and select the optimal oxidation process. Results show that addition of hydrogen peroxide/Fenton's reagent increased the UV degradation rates of all pesticides, and data were simulated through kinetic modeling. Kinetic results evidence pseudo first-order degradation, with the rate constant of reaction as 3.3 × 10 -4 , 2.07 × 10 -2 and 1.

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There are great interests in photocatalytic oxidation of contaminants using advanced oxidation processes (AOP) based on photocatalytic oxidation in recent years. The main aim of the paper is to develop a method which takes care of energy and water conservation together. The study was performed on photocatalytic disinfection of total coliform (TC) bacteria as water microbial pollution and reducing the chemical oxygen demand (COD) as organic pollution index using catalytic and oxidant in present of sun light. The municipal wastewater was monitored for TC and in then was irradiated with solar light, solar light/TiO 2 , and solar light/TiO 2 /H 2 O 2 . Various parameters such as contact time, pH, and different concentration of TiO 2 and H 2 O 2 were studied for their effect on reaction process. The result showed that in presence of solar light, catalyst, and oxidant, very effective disinfection and reduction of TC and COD took place. 95.2% and 97% of TC and COD were reduced by irradiation for 240-300 min. Based on the results of various AOP combinations, Solar photolytic, solar/TiO 2 , Solar/TiO 2 /H 2 O 2 , the rate of COD, and TC removal was in the order of TiO 2 /H 2 O 2 > TiO 2 > Solar photolytic. It can be suggested as an effective treatment method for wastewater containing microbial and organic contamination.