Biological remediation technologies for dyes and heavy metals in wastewater treatment: New insight.

Chemical coagulants have been extensively used in wastewater treatment from industrial processes due to their removal efficiencies. Notwithstanding, recent studies have reported concerns over the existence of lingering or incurable diseases, resulting from residues of metals from these non-degradable chemical coagulants which remain in the water even after treatment. The sludge produced from the treatment has also been affirmed to be hazardous and non-biodegradable, causing harm to the environment. The potential application of plant-based coagulants as suitable alternatives to chemical coagulants due to their biodegradability, economical, non-toxic, and lower sludge volume, and treatment cost; is being studied in industrial wastewater treatment. Presented in this review is the state of heart of revolutionary technique for green coagulant preparation, their properties, and application in wastewater treatment. Highlighted is the current development on improving and purification techniques of the coagulants, and probable use of dual or combine coagulants. The review also critically identifies notable research gaps based on the current limitations in previous research to valorizing potential applications.

Revolutionary technique for sustainable plant-based green coagulants in industrial wastewater treatment—A review

Chemically enhanced primary treatment (CEPT) is a process that uses coagulant and/or flocculant chemicals to remove suspended solids, organic carbon, and nutrients from wastewater. Although it is not a new technology, it has received much attention in recent years due to its increased treatment capacity and related benefits compared to the conventional primary treatment process. CEPT involves both physical and chemical processes. Alum and iron salts are the commonly used coagulants in CEPT. Several types of anionic, cationic, and uncharged polymers are used as flocculants, where poly aluminum chloride (PACL) and polyacrylamide (PAM) are the widely used ones. Some of the coagulants and flocculants used may have inhibitory and/or toxicity effects on downstream treatment and recovery processes. There has been an increasing amount of work on the treatment of wastewaters from various sources using CEPT. These wastewaters can range from municipal/domestic wastewater, combined sewer overflow, landfill leachate, cattle manure digestate to wastewaters from textile industry, pulp and paper mill, slaughterhouse, milk processing plant, tannery and others. In recent cases, CEPT is employed to enhance carbon redirection for recovery and substantially reduce the organic load to secondary treatment processes. CEPTs can remove between 43.1–95.6% of COD, 70.0–99.5% suspended solids, and 40.0–99.3% of phosphate depending on the characteristics of wastewater treated and type of coagulants and/or flocculants used. This article reviews the application, chemicals used so far, removal efficiencies, challenges, and environmental impacts of CEPT.

https://www.mdpi.com/2071-1050/12/15/5928/pdf

Revisiting Chemically Enhanced Primary Treatment of Wastewater: A Review

Biodegradable gelatin composite hydrogels filled with cellulose for chromium (VI) adsorption from contaminated water

Industrial effluents are a menace to the environment and the fact that their characteristics vary from industry-to-industry only adds to the complex challenge they offer to the engineers and scientists. Resource-efficient and environment-friendly solutions to this hazard are a call of the hour. Coagulation, by synthetic chemicals, has been used as a cost-effective and efficient method for managing the effluents generated by a large number of industries. However, the synthetic chemicals themselves are a cause of concern due to their non-native nature, non-degradability, and health conditions associated with their left-over residues. Natural coagulants offer a cost-effective, environment-friendly, and sustainable alternative to the application of synthetic chemicals. Such natural coagulants, despite their demonstrated effectiveness in treating the industrial wastewaters, have their own limitations and are yet to be investigated for large-scale applications. The current work presents a state-of-the-art review of the natural coagulants' application in treating industrial wastewaters and their relative advantages and disadvantages as compared to the chemical coagulants. Future research areas have also been identified that may ultimately lead to the large-scale commercial application of natural coagulants and will result in an environment-friendly and sustainable solution to the problems created by industrial effluents and synthetic chemical coagulants.

/pdf/use-of-natural-coagulants-for-industrial-wastewater-521pbfba27.pdf

Use of natural coagulants for industrial wastewater treatment.

A review natural polymeric coagulants in wastewater treatment

Treatment of gray wastewater and heavy metal removal from aqueous medium using hydrogels based on novel crosslinkers

Sugar based xanthates viz D-sorbitol xanthate and D-mannitol xanthate (DSX1, DSX2, DMX1 and DMX2) have been synthesized by the reaction of D-sorbitol (DS)/ D-mannitol (DM) with carbon disulfide (CS2) in basic medium at room temperature by varying carbon disulphide and base ratio with respect to sugars. The synthesized xanthates were extracted with ether, and dried in air. The xanthates were characterized by micro analytical data, Elemental analysis (C, H, O, S), Fourier transform infrared (FTIR) spectroscopy, and H nuclear magnetic resonance (1HNMR) spectroscopy. The synthesized xanthates were used for the removal of Cuand Ni form aqueous solutions. The metal complexes formed during the process of removal of metal ions were confirmed with FTIR spectroscopy. The removal of copper and nickel metal from water was quantitatively determined by UV-visible absorption spectroscopy.

/pdf/synthesis-of-novel-sugar-based-xanthates-for-the-removal-of-7en0mn35c0.pdf

Amar Nath

Papers

A review natural polymeric coagulants in wastewater treatment

Treatment of gray wastewater and heavy metal removal from aqueous medium using hydrogels based on novel crosslinkers

Synthesis of novel sugar based xanthates for the removal of copper and nickel harmful heavy metals from water

Study on the effect of temperature on polymerization of ethyl methacrylate monomer