Rapid Determination of Indirect COD and Polyvinyl Alcohol from Textile Desizing Wastewater

Abstract

PVA (Polyvinyl alcohol) is completely degraded and utilized by non-ubiquitous microorganisms as a sole source of carbon. PVA containing effluent treatments are not preferred because of high cost. PVA causes serious environmental pollution hence the objective of this work was to establish rapid and reliable method for analysis of COD (Chemical oxygen demand) and PVA concentration in textile desizing or any PVA containing effluent. Two indirect methods namely COD by TC (Total carbon) and TOC (Total organic carbon) were compared with COD chemical as standard. The percentage deviation of 0-0.8% PVA was same in both indirect COD by TC and TOC whereas for 1 - 4% PVA it was <10 for COD by TC and 30 to 35 for COD by TOC. Standard deviation range for indirect COD by TC was 600-3000, while indirect COD by TOC was 1500-28000. Indirect COD by TC was found more precise than indirect COD by TOC for PVA containing samples and more rapid than COD chemical. The spectrophotometrically analyzing PVA concentration by iodine method was reconfirmed and absorbance at 690 nm indicates corresponding PVA concentration. TC and iodine methods of analyzing PVA containing effluent were rapid and precise than conventional chemical COD method; these could be useful in the faster pollution detection and environmental protection from PVA.

Keywords: Polyvinyl alcohol; chemical oxygen demand; total organic carbon; total carbon