Envisioning the innovative approaches to achieve circular economy in the water and wastewater sector.

Given the challenges of urbanization and rapid resource depletion, policymakers have been compelled to abandon the old sequential paradigm of "take-make-use-dispose" to a circular approach that prioritizes preservation of natural resources. The circular economy represents a sustainable management concept that focuses on reducing, recovering, reusing, and recycling waste. While significant strides have been made in implementing circular economy principles in various industries such as automotive, electronics, and construction, particular attention has been given to the water and wastewater domains due to imbalances in water resources. Here we review the global progress of circular economy adoptability in the water and wastewater domains, considering technical, environmental, economic, and social perspectives. It assesses the current state of circular economy integration in the wastewater domain worldwide and presents approaches to promote and accelerate its adoption. The study critically examines the principles of waste management, known as the 6Rs (reclaim, restore, recycle, reduce, recover, reuse), in order to formulate effective strategies for integrating circular economy practices in the water and wastewater domains. Additionally, the study provides an overview of existing research conducted on different aspects of circular economy. Finally, the study analyzes the challenges and opportunities associated with implementing circular economy principles in the water sector.

An assessment of hospital wastewater and biomedical waste generation, existing legislations, risk assessment, treatment processes, and scenario during COVID-19.

Hospitals release significant quantities of wastewater (HWW) and biomedical waste (BMW), which hosts a wide range of contaminants that can adversely affect the environment if left untreated. The COVID-19 outbreak has further increased hospital waste generation over the past two years. In this context, a thorough literature study was carried out to reveal the negative implications of untreated hospital waste and delineate the proper ways to handle them. Conventional treatment methods can remove only 50%-70% of the emerging contaminants (ECs) present in the HWW. Still, many countries have not implemented suitable treatment methods to treat the HWW in-situ. This review presents an overview of worldwide HWW generation, regulations, and guidelines on HWW management and highlights the various treatment techniques for efficiently removing ECs from HWW. When combined with advanced oxidation processes, biological or physical treatment processes could remove around 90% of ECs. Analgesics were found to be more easily removed than antibiotics, ß-blockers, and X-ray contrast media. The different environmental implications of BMW have also been highlighted. Mishandling of BMW can spread infections, deadly diseases, and hazardous waste into the environment. Hence, the different steps associated with collection to final disposal of BMW have been delineated to minimize the associated health risks. The paper circumscribes the multiple aspects of efficient hospital waste management and may be instrumental during the COVID-19 pandemic when the waste generation from all hospitals worldwide has increased significantly.

Enhanced tetracycline removal by in-situ NiFe nanoparticles coated sand in column reactor.

The occurrence of various antibiotics in natural waters poses an emerging environmental concern. Tetracycline (TC) is a frequently used antibiotic in human therapy, veterinary industry, and agricultural sectors. In the current study, TC removal from aqueous solutions was studied using binary Nickel/nano zero valent iron particles (NiFe nano particles) and in-situ NiFe nanoparticles coated sand (IS-NiFe). Removal of TC using bimetallic NiFe particles was optimized with help of response surface methodology (RSM). Using the optimized parameters (concentration of TC: 20 mg/L; NiFe dose: 120 mg/L; time of interaction: 90 min), 99.43 ±â€¯0.98% removal of TC was noted. Further, IS-NiFe was packed in the column reactors and effects of different parameters like flow rate (1-3 mL/min), bed height (3-10 cm) and inlet TC concentration (20-60 mg/L) on breakthrough characteristics were examined. Under the optimized conditions the removal capacity in the column reactor was 1198 ±â€¯40.2 mg/g using IS-NiFe. The column kinetic data were successfully fitted with Adams- Bohart and Thomas models. TC removal efficiency of IS-NiFe in column reactors was tested with TC (20 mg/L) spiked lake water, ground water, and tap water and the removal capacity was noted to be 698.55 ±â€¯11.21, 764.17 ±â€¯6.78, and 801.7 ±â€¯13.26 mg/g respectively.