Modeling and transport parameters during nanofiltration of degreasing effluent from a tannery

Abstract

Degreasing effluent from a tannery is treated using a single-step membrane separation (nanofiltration) process in continuous cross-flow mode. The flow regimes encompass the laminar and turbulent zones, including laminar flows with turbulent promoters. Experimental results are reported in the range of transmembrane pressure drop from 828 to 1242 kPa for all three flow regimes. More than 50% flux enhancement is observed by using turbulent promoters compared to purely laminar flow. The performance criteria of the filtration are evaluated in terms of chemical oxygen demand (COD), total dissolved solids (TDS), total solids (TS), pH and conductivity of the permeate. The proposed scheme successfully reduces COD to well below the permissible limits (250 mg/l). A combination of osmotic pressure and solution-diffusion model is used for nanofiltration. Three relevant transport coefficients, namely, the effective osmotic coefficient, solute diffusivity and solute permeability through the membrane are estimated by minimising the sum of errors between the experimental and calculated

Membranes and Integrated Membrane Operations as Clean Technologies in the Leather Industry

“…A NF process was studied by Prabhavathy and De [39] in order to reduce the COD of spent degreasing baths within the permissible limits in India (250 mg/L). The COD of the initial bath was previously reduced from 3737.3 mg/L up to 734.4 mg/L by coagulation with alum.…”

Decontamination of tannery industry wastewater containing high organic load along with Cr3+: a comparative study

“…Prabhavathy et al . attempted a single step membrane separation (nanofiltration) process for the treatment of degreasing effluent from a tannery. In one study, the COD and chromium were removed from tannery wastewater using chemical coagulation by Song et al .…”