Estimation of Surfactants Discharge Loadings by Domestic Detergent Use in Thailand

Abstract

Decentralized water reclamation and reuse has been proposed in peri-urban areas of Bangkok where rapid urbanization and industrialization have been causing increases in water demand and water shortages. It was suggested that domestic greywater from laundry and bath and shower wastewater containing low BOD are acceptable for reclamation and reuse by the residents in the area. Although the water contains high concentrations of surfactants, little is about known on their actual discharge loadings in Thailand. Therefore, the MBAS and LAS contents of commercial detergents, including liquid soap, shampoo, liquid dish soap and powdered laundry soap were measured. The daily MBAS and LAS discharge loadings per person were estimated to be 4.44 g/p/d and 3.08 g/p/d, respectively by using daily usage of the detergents and their share factors obtained by a questionnaire survey in the previous study. Powdered laundry detergent contributed the most to MBAS loadings, while liquid dish soap, shampoo and liquid soap were the next. The LAS loadings were primarily derived from liquid dish soap and powdered laundry detergent. The decrease in the surfactant concentrations measured in drainages and canals suggested that biological treatment was applicable for the reclamation of greywater containing detergents.