Hydrogeochemical controlling variables for the high rate of groundwater contamination in a shallow hard rock aquifer of the semi-arid region of Medchal District, Telangana State, South India, and its associated health risk to children and adults were studied in detail. A total of 56 groundwater samples were analysed for major ion chemistry in pre- and post-monsoon seasons in 2019 year. Spatial distribution, hydrochemical facies, water–rock interaction, health risk assessment, carcinogenic risk, and principal component analyses were carried out to assess the water quality. Spatial distribution of nitrate and fluoride concentrations, high values were observed in the northern, southern, central, and south-western parts of the region. In terms of NO3−, about 88% and 63% and for F− 45% and 32% of the groundwater samples are non-acceptable limits of nitrate 45 mg/l and fluoride 1.5 mg/l during pre- and post-monsoon seasons, respectively. Modified Gibb’s plot showed the majority of the area is dominated by rock dominance and evaporation mechanisms. Statistical analysis reveals that water chemistry is governed by weathering of feldspar minerals and the cation exchange reaction mechanism. The petro-graphical studies revealed the dominance of plagioclase, orthoclase, quartz, biotite, apatite, and hornblende minerals in the host rock. The factor analysis results reveal that the geogenic and anthropogenic activities contribute to groundwater chemistry. Health risk assessment was carried out by calculating the hazard quotient (HQ) on the basis of intake exposure of groundwater, as per the USEPA. Results were obtained for total hazard index value greater than 1 for adults and children, which causes non-cancerous health effects.

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Abatement of water pollution is being a major concern to be dealt with, as the scarcity of water for basic needs of human beings is increasing drastically. As a part of diminishing water pollution, treatment of industrial wastewater prior to disposal plays a paramount role. Due to the typical characteristics of pesticide, intermediate industrial waste water the treatment is also challenging issue. In this study three different sequential methodologies (Methodology-I: combined rotavapour distillation, fenton and anaerobic biological process, Methodology-II: combined rotavapour distillation, photo fenton and anaerobic biological process, Methodology-III combined coagulation, fenton, electro oxidation and anaerobic biological process) has been evaluated for the treatment of pesticide intermediate industrial wastewater. Among the three sequential methodologies opted in this study for the treatment of pesticide intermediate industrial wastewater, percentage removal of COD was 95% in methodology-1 (i.e. combined rotavapor distillation, fenton and anaerobic biological treatment).

Landfill leachate contains organic, inorganic compounds, heavy metals, ammonia, and xenobiotic compounds which are considered unsafe for discharging into surface water which requires to be treated before its discharge into the water. In this paper, preliminary studies are reported on the application of Fenton, Struvite, and Electrooxidation processes for the removal of Chemical Oxygen Demand (COD) and ammonia from landfill leachate. Various operational parameters like pH, dosage, reaction time, and applied voltage were optimized in laboratory batch experiments and evaluated for removal of COD and ammonia. Results demonstrated that the Fenton process could effectively remove COD and ammonia by 75% and 23% respectively at 210 min for Fe+2:H2O2: 1:5 at a fixed pH 3. The Struvite process has been effective in the removal of ammonia by 74% at pH 9 with the dosage of Mg+2:PO43-:NH4+ at 1:1:1 ratio. Results from Electrooxidation for COD and ammonia were observed as 58.25% and 44% respectively at the applied voltage 8 V for a reaction time of 60 min. The efficiency of treatment processes was also evaluated in Sequential processes for COD and ammonia i.e., Sequence-I (Fenton-Electrooxidation-Struvite) and Sequence-II (Fenton-Struvite) at pre-optimized conditions. The sequential processes have been depicted, the removal efficiencies of COD and ammonia of 89% and 82% by Sequence-I; 76.77%, and 77% by Sequence-II respectively. The present study demonstrates that Fenton followed by Electrooxidation and Struvite is an effective treatment process that can enhance the treatment of landfill leachate.

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