Biodegradation of Coir Geotextiles Attached Media in Aerobic Biological Wastewater Treatment

Abstract

Coir is a hard and tough organic fibre, rich in cellulose and lignin, and possesses high specific area and wetting ability - factors which are important for bacterial adhesion in fixed film processes. Few studies have been reported on the durability of coir geotextiles, when used in Civil Engineering applications such as slope protection works. However, its durability when used as the media in biofilters, for wastewater treatment extensively has not been studied yet. Durability of coir geotextiles has been assessed by keeping it in wet condition and measuring the tensile strength of the fibres, at different times. In the present study, coir geotextiles that were used as the attachment media in a biofilter, for treatment of organic rich wastewater was tested for durability. The units were operated as aerobic, gravity flow filters. Different wastewater parameters were employed in each of these runs. Tensile strength of the fibres was determined after each run. Results show that loss of tensile strength (or degradation) is influenced by the characteristics of the effluent wastewater to the filter, due to the growth of microorganisms which depends upon the concentration of substrates in the wastewater. Permeability studies shows reduction in permeability, is influenced by the organic loading rate on the filters and the duration of filter operation. SEM studies and E-DAX analysis shows the biodegradation of the fibres constituents, influenced by the substrate concentration.