The utilization of bentonite enhanced termite mound soil mixture as filter for the treatment of paint industrial effluent

Abstract

AbstractThis research investigates the applicability of bentonite enhanced termite mound soil mixture as an alternative filter medium for paint industrial wastewater (PIWW) management in a constructed pilot-scale filtration tank with four different sections. The mixture of bentonite (BC) and termite mound soil (MS) used as the filter was proportioned by percentage weight as (100% MS), $${\text{(5\% BC}} + {\text{95\% MS),}}$$ (5\% BC + 95\% MS), $${\text{(10\% BC}} + {\text{90\% MS),}}$$ (10\% BC + 90\% MS), $${\text{(15\% BC}} + {\text{85\% MS)}}$$ (15\% BC + 85\% MS) and placed into four sections, respectively. The filter materials were compacted, cured and subjected to wastewater loading for 30 weeks. The results obtained from the analysis of the filtrate samples revealed that filter with 15% BC content generally exhibited high and effective pollutant removal efficiencies of 51.3%, 98.9%, and 72.7% for total dissolved solids, total suspended solids, and copper, respectively, while a maximum removal efficiency of 100% was recorded for lead, chromium and cadmium. The pollutants (TDS, TSS, Pb, Cr, Cu and Cd) concentrations of the treated PIWW were below the National Environmental Standards and Regulations Enforcement Agency permissible limits for discharge. Hence, the 15% bentonite and 85% termite mound soil mixtures are recommended for the small-scale paint industries as a point of use measure for effective pollutant removal. Its application would mitigate the degradation of environmental resources caused by indiscriminate disposal of untreated effluent.