Reversing the damage: ecological restoration of polluted water bodies affected by pollutants due to anthropogenic activities.

Aquatic ecosystems provide a large number of cultural, regulating, and supporting services to humans and play a pivotal role in sustaining freshwater-dependent ecosystems. However, an increase in human population coupled with economic growth in the last few decades has severely affected their functioning and ecological health. This has led to an increase in concentrations of pollutants originating from anthropogenic activities such as heavy metals, plastics, semi-volatile organic compounds, and endocrine disruptors. These pollutants provoke deleterious impacts on aquatic biodiversity and affect the water quality and functioning. In this paper, we discuss the sources and impacts of such pollutants as well as restoration techniques for reducing their impact on aquatic ecosystems. Several physical and chemical ecological restoration techniques, such as dredging, sediment capping, water diversion, adsorption, aeration, and flushing, can be employed to improve the water quality of water bodies. Additionally, biological techniques such as phytoremediation, phycoremediation, the use of biomembranes, and the construction of ecological floating beds can be employed to increase the population of aquatic organisms and improve the overall ecological health of aquatic ecosystems. Restoration techniques can effectively reduce the concentrations of suspended solids and dissolved phosphorus and increase the levels of dissolved oxygen. The restoration techniques for improving the ecological health of water bodies should not be limited to simply improving the water quality but should also focus on improving the biological processes and ecosystem functioning since it is essential to mitigate the adverse effects of pollutants and restore the vital ecosystem services provided by water bodies for future generations.

Comparison of TiO2 catalysis and Fenton's treatment for rapid degradation of Remazol Red Dye in textile industry effluent.

The contamination of water bodies by toxic industrial effluents is a serious threat to environment and the exposed organisms. The treatment of carcinogenic azo dyes in wastewater of grossly polluting textile industry is a major challenge considering the persistent nature of chemical dyes against biological treatment. The present study explores efficacy of advanced oxidation processes-photocatalysis and photo-Fenton, towards degradation of Remazol Red dye in the textile industry effluent. It was observed that both processes can completely remove the colour and approximately 85% mineralization of the dye within reaction time of 60 min and 8 min, respectively. The economic analysis placed photo-Fenton as a cost-effective method with treatment cost of approx. 0.0090 US $/litre of wastewater containing Remazol Red dye. Although, Photocatalysis was relatively slow, it is substantially effective in removal/degradation of colour from textile effluent against the biological treatment. The study concludes that photo-Fenton and Photocatalysis are cost-effective and substantial treatment options for removal of toxicity arising from coloured textile effluents.