Tannery Effluents: Current Practices, Environmental Consequences, Human Health Risks, and Treatment Options

Abstract

The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro‐Fenton, and photo‐Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health.

Acute Ecotoxicity Potential of Untreated Tannery Wastewater Release in Arequipa, Southern Peru

“…Speciation is particularly important for the latter due to the carcinogenic and mobile nature of oxidized hexavalent chromium (Cr 6+ ) which is of clear concern in both tannery wastewater and other routes of environmental release [2,8]. Collectively, this combination of wastewater constituents can exert a variety of effects on receiving ecosystems if inadequately treated prior to discharge, such as water pollution [9], aquatic ecosystem damage [10], biodiversity loss [11], and even soil contamination [12] and the disruption of microbial communities [13], among many others.…”

Improving Tannery Wastewater Treatments Using an Additional Microbial Treatment with a Bacterial–Fungal Consortium

“…The pollutants originate from both animal skin and chemicals used in the tanning process. Animal skin particles consume oxygen and release nutrients when released into surface waters [1]. The chemicals include heavy metals, particularly chromium (Cr) [2,3].…”

“…In addition, pesticides, salts, and acids are found in high concentrations [4,5]. The phyto-and genotoxicity of these chemicals has been shown in numerous studies [1,[6][7][8][9]. As much as 40% of the environmental heavy metal load has been found to originate from tanning [10].…”