Evaluation of adsorption capacity of biochar mixed substrate to treat tannery wastewater by constructed wetland

Abstract

In the developing countries increase in population, improper urbanization and industrialization causing many issues to the ecosystem and the environment. Industrial Pollution has been a great concern for decades. Mainly Tanning industries located in many places of India as small scale industry. These small scale industries mostly running in the houses discharge partially treated and untreated effluents with high concentration of Chromium V1 into the water bodies. Research Study was initiated with proto type lab scale model to identify a suitable alternative technique to reduce the concentration toxic compound present in Chrome tannery wastewater. Coupling of two techniques like constructed wetland and Biochar as adsorbent. Main objective is to identify the efficiency of constructed wetland with coconut shell biochar as an adsorbent. Constructed wetlands (CWs) are artificial developed engineered systems which are formulated and constructed to operate the natural processes like vegetative wetlands, natural soils, with connected microbial assemblages helps in treating wastewaters by the action of filtration, adsorption, sedimentation and phytoremediation. Biochar was produced from the coconut shell which was heated to temperatures between 250 and 750°C, under less oxygen concentrations. Constructed wetland coupled with Biochar. The biochar was mixed into the substrate of constructed wetlands. By using the biochar substrate the constructed wetland coupled with biochar was developed as lab scale model. Different trails were carried with the model using tannery wastewater collected from local tannery unit. The adsorbent biochar acts as a treating media which reduces the color of the wastewater and also reduction in chromium concentration of wastewater.The constructed wetland assemblage helps in reduction of other organic concentration and total solids of the wastewater. Based on the different trials in the lab scale model a good reduction in color, chromium, BOD, COD can be observed. More than 60 to 70 % reduction efficiency was achieved with the help lab scale model. It is possible to achieve 4’R (Reduce, Reuse, Recycle and Recovery) if the same was carried out in a large scale.