Comprehensive review on wastewater discharged from the coal-related industries – characteristics and treatment strategies

Abstract

Wastewaters discharged from various coal-related activities deteriorate fresh water quality and inflict possibilities of groundwater contamination. Their characteristics mostly depend on the parent coal properties, though some of the pollutants are cyanide, thiocyanate, ammonia, phenol, heavy metals and suspended solids. This paper has reviewed the treatment techniques along with the characteristics of all such kinds of wastewater and also identified the challenges and future perspectives. Primarily, demineralization of coal can attenuate and control release of pollutants in wastewaters if implemented successfully. Mine water from non-lignite mines can be purified using simple techniques, for its reutilization. Acidic mine water and leachates can be treated using passive bioreactors with microbial activity, different organic substrates and limestone drains. Additionally bio-electrochemical systems, membranes, macrocapsules, zeolite filters, ores, physical barriers, and aquatic plants can also be used at various stages. Coal washery wastewater can be treated using natural coagulants obtained from plant extracts along with conventional coagulants. Nitrification and denitrification bacteria fixed in reactors along with activated carbon and zero-valent iron can treat coke oven wastewater. Some other sophisticated techniques are vacuum distillation, super critical oxidation, nanofiltration and reverse osmosis. Practical use of these methods, wisely in an integrated way, can reduce freshwater consumption.

Enhancing Phenol Conversion Rates in Saline Anaerobic Membrane Bioreactor Using Acetate and Butyrate as Additional Carbon and Energy Sources

“…Nevertheless, other compounds such as acetate or butyrate, which could be used by microorganisms as carbon and energy sources (CES), are also present in coal gasification wastewater as common contaminants (Singer et al, 1978;Blum et al, 1986;Ji et al, 2016). Besides, it has been reported that coalrelated industries wastewaters have a high concentration of total dissolved solids, ranging from 174 to 2,000 mg•L −1 (Maiti et al, 2019). Furthermore, under closed-water-loops, increasing salinity in the wastewater is expected.…”

Biological treatment of coke plant effluents: from a microbiological perspective

“…Some of these compounds are volatile under the conditions present in raw wastewater (Kjeldsen 1999;Zhu et al 2018); therefore, a direct exposure to such liquids constitutes a serious risk to human health. The composition of coke plant effluents depends mainly on the quality of coals used and the operating and technological parameters of coke ovens (Maiti et al 2019;Zhu et al 2018) (Table 1).…”

“…Various techniques available combine different physical, chemical and biological processes, and the biological unit is an almost indispensable part of a successful and costeffective treatment process (Zhao and Liu 2016;Zhu et al 2018). In general, up to 90-99% reduction in contaminants can be achieved (Kim et al 2008a;Maiti et al 2019;Tong et al 2018;Zhu et al 2018).…”

“…Although information available on the structure and function of microbial communities in wastewater treatment processes increased considerably in the past decades, most of the studies were conducted on municipal (i.e., domestic) wastewaters (Cydzik-Kwiatkowska and Zielińska 2016;Wu et al 2019), and research focusing on the background of microbial processes during the treatment of coke plant effluents is still limited. Furthermore, recent reviews (Kwiecińska et al 2017;Maiti et al 2019;Zhao and Liu 2016;Zhu et al 2018) on coking wastewater treatment focus mainly on the technological aspects of different purification strategies, while microbiological findings (e.g., those that were obtained with high-throughput DNA sequencing methods during the last years) have not been considered. Therefore, the major aim of this review is to summarize the current knowledge on microbiological processes related to coke plant effluent treatment, which could help the optimization of available technologies and aid the design of new management techniques.…”

Phycoremediation of pollutants from secondary treated coke-oven wastewater using poultry litter as nutrient source: a cost-effective polishing technique

“…Generally, raw COW is characterized by high contents of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), phenol, ammoniacal-N (NH 4 þ ), cyanide, sulfide, and thiocyanate (Kwiecinśka-Mydlak et al 2019). While the physico-chemical methods such as pH neutralization, flow equalization, coagulation, and chemical oxidation were used as primary treatment for reduction of COD to BOD ratio of coke-oven wastewater, membrane-based technique, ion exchange separation, electro-coagulation, photocatalysis, and adsorption in general, were used as a tertiary treatment method or as a polishing method in effluent treatment plant (Maiti et al 2019). Coagulation and precipitation methods and chemical oxidation methods are having disadvantages of high chemical cost, generation of sludge, and inefficiency to remove pollutants at ppm level (Waghmare & Arfin 2015).…”