Tannery wastewater treatment: conventional and promising processes, an updated 20-year review

Abstract

Mismanagement of various wastes especially waste water produced by tanning processes has caused serious environmental problems and ultimately impaired human health. Constant efforts have been making to alleviate the pollution of tannery wastewater (TWW), yet terminal treatment still takes dominance. In this review, research on TWW treatment from 2000 to 2021 was summarized, and main methods such as coagulation and flocculation, adsorption, biological treatment, membrane filtration, advanced oxidation process were briefly discussed. More detailed introduction was given to the method of electrochemical treatment since it has excellent performance such as environmental friendliness and high efficiency, hence attracting more and more research attention in recent years. In view of the harsh physi-chemical conditions of TWW, integrated or combined treatment methods are accordingly recommended with better performance and multi-function, however comprehensive studies on optimization of methods combination and cost-effectiveness are needed. The certain issues that the residue Cr in treatment sludge and high salinity in effluent still remain were put forward in this work and potential solutions were provided. Moreover, this review proposed the perspective that realizing multi-function, recycling, and intensification should be the developing direction for future TWW treatment. This review is expected to provide a general guide for researchers who aspire to ameliorate TWW pollution problems and understand various methods utilized in this field. Graphical abstract

Industrial Water Demand and Wastewater Generation: Challenges for Bangladesh’s Water Industry

“…Tertiary treatment can be carried out by membrane filtration or reverse osmosis followed by evaporation or electrodialysis. 59 In developed countries, tannery wastewater treatment is usually carried out to a higher degree to meet the discharge standards for nitrogen. Advanced integrated pond systems, 60 sequential batch reactor (SBR) technology, 61,62 and membrane bioreactor (MBR) technology 63 are among the recently developed alternatives for the removal of both organic matter and nitrogen from tannery effluent.…”

“…Tertiary treatment is essential for removing refractory organic compounds and inorganic salts. Tertiary treatment can be carried out by membrane filtration or reverse osmosis followed by evaporation or electrodialysis . In developed countries, tannery wastewater treatment is usually carried out to a higher degree to meet the discharge standards for nitrogen.…”

Analysis of the Capacity of the Fenton Process for the Treatment of Polluted Wastewater from the Leather Dyeing Industry

“…The effluent originating from the dyeing stage (WWDS) is considered the bottleneck during the treatment of wastewater from tanning, since it contains the largest number of recalcitrant substances. In fact, many researchers have made reports directed at WWDS environmental risk and toxicity assessments confirming their negative impact when discharged without appropriate treatment into the environment [ 9 ]. Furthermore, industrial wastewater treatment is an important issue in the current context, not only to protect the environment from pollution (reducing and/or eliminating pollutants) but also to conserve water resources, reduce water stress, and promote the sustainability.…”

Water decontamination under high salinity using the TiO2 NT/PbO2–Cu electrochemical oxidation system: kinetics mechanism and DFT studies

“…Sulfate salts were considered inert substances in the electrochemical oxidation system before, serving as mobile ions in favor of current transfer. 67 However, recent studies have found that a certain number of sulfate radicals could be obtained in sulfate-rich electrolytes. Sulfate radicals, which show excellent advantages in persistent organic pollutants' degradation, are thus exploited in wastewater treatment practices, not only because they have a higher redox potential than HO˙ ( E 0 (SO 4 ˙ − /SO 4 2− ) = 2.5–3.0 V) but also a wider range of working pH (2.0–9.0).…”