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Adsorption capacity of manganese powder synthesized from spent battery waste solution was analyzed for simultaneous removal of congo red and hexavalent chromium. Manganese powder was synthesized by heat treatment followed by reaction with sodium borohydride to spent lithium-ion batteries. The removal conditions viz., pH, dosage of manganese and various concentrations of congo red and hexavalent chromium were optimized. The synthesized manganese powder was characterized by X-ray fluorescence spectrometer (XRF), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Further, FESEM was done to observe the difference in surface morphology of the particles with and without treatment. The adsorption performance was studied and the highest adsorption by the zero manganese was 475 mg/g and 125 mg/g for CR and Cr (VI), respectively when different concentrations of the contaminants (400 mg/L CR and 100 mg/L Cr (VI)) was used. Under the optimum conditions, simultaneous removal from 450 mg/L of CR to 250 mg/L and 125 mg/L of Cr (VI) to around 74 mg/L was achieved. Desorption study of the treated zero manganese exhibited that acid treatment (0.1 M HCl) for CR and alkali treatment (0.1 M NaOH) for Cr (VI) as the suitable reagent for desorption.

Groundwater samples were collected from the Brahmaputra Flood Plains (BFP) to study the effect of river proximity on the arsenic (As) and fluoride levels (F − ). Arsenic and F − contamination was found to be higher in the south bank. Higher carbonate weathering was found to elevate the alkalinity in the south bank which in turn appeared to influence the groundwater As and F − levels. Low NO 3 − levels in the groundwater indicated the existence of a predominantly reducing condition, which is confirmed by low ORP levels in majority of the groundwater samples. Positive correlation between As and Fe, along with close grouping in principal components analysis and hierarchical cluster analysis indicated the involvement of reductive hydrolysis of Fe (hydr)oxides. Principal components analysis showed that reductive hydrolysis was more common in the south bank, which could explain the higher As levels detected in that bank. Higher sedimentation rates on the south bank could also influence the elevated As levels in its groundwater. Co-occurrence of As and F − was also found to be more likely in the south bank as indicated by hierarchical cluster analysis, the process appeared to be influenced by dissolution of Fe (hydr)oxides. Distance from the river and groundwater As level appear to be related, newer sediments close to the river are more likely to have higher As compared to older sediments away from the river. Fluoride on the other hand appears to have an inverse relation with river proximity, as recharge interrupts rock-water interaction, which is the main pathway for F − release. Overall occurrence of groundwater As appears to be a more widespread problem in the floodplains, while F − in groundwater is localised and limited to isolated pockets which promote higher mineral and water interaction over long periods.

This paper aims to re-examine the current urban water use system in the urban areas of developing country discuss a better way for resilience investigation. The study proposes that analysis of data on the available amount of chemical and biological contamination in water is the first pressing requirement for this approach. In addition, climate change is causing an uneven pattern of rainfall and severe drought conditions and thus need a substantial attention to delineate the preventive ways for its mitigation in the water-scarce area as well as areas with high groundwater depletion or area contributing to the recharge. Most of the Indian rivers are polluted, and hence the removal of pollutants is an additional task for making a watershed resilient. There is a necessity to evaluate urban water for its better definition and develop the Water Quality Information Platform (WQIP) for layman understanding. The contemporary need for an approach for sustainable water supply must be developed with an understanding of the expected climate change scenario. The idea of “your experience, my learning opportunity” was found very relevant in implementing the developed world experience to a developing nation scenario. Study concludes that without a strong will power and action mantra of “Targeting the target: Bull's eye approach”, the resilience system will not be evolved. This study will have an impact on the critical scientific knowledge of deterioration of water quality, posing a threat to potable water availability, and also on the development of sustainable water management.