Green environment suffers by discharging of high-chromium-containing wastewater from the tanneries at Hazaribagh, Bangladesh

Application of chromium and discharging of high-chromium-containing wastewater is a major concern in leather processing. In tanning process, animal hide/skin collagen is stabilized against biodegradability mostly with basic chromium sulfate. Subsequently in chrome tanning, a fraction of chromium remains in the tan liquor, which is discharged in the waste steam. The study focused on the characterization of discharged chromium-containing wastewater from the tanneries. Results indicate that high concentration of chromium ranging from 2656 to 5420 mg/L was discharged as wastewater after wet-blue production. The physical parameter of spent chrome liquor: total solids (TS) were extremely high. The chemical parameter such as pH (2.4–3.0) was highly acidic. A fraction of discharged spent chrome liquor is directly mixed with the water of the River Buriganga, which causes serious environmental pollution; another fraction of chromium is settled out in the lagoon or adsorbed by sediment/soil. It is suspected that the adsorbed chromium could be eluted to groundwater in the tannery area, which could be a great threat in the near future. Practicing chromium recovery and reuse systems might be a good approach to make leather production environmental friendly, and consequently Bangladesh could save huge amounts of chemical costs.