Study On Treatment Of Domestic Laundry Wastewater In A Constructed Rapid Infiltration System

As one of the main components of washing powder, Linear Alkylbenzene Sulphonates (LAS) will lead to a large amount of pollution and do great harm to the balance of the ecosystem by forming emulsified colloid substances if used and discharged directly into surface waters with domestic laundry Wastewater. In this paper, an effective method is proposed to reduce the negative effect of LAS on the water environment by using a constructed rapid infiltration system (CRIS) to treat laundry Wastewater before it is discharged into surface water. The technique was studied at the laboratory scale and the performance and stability of the system were analyzed. The sustainable use of CRIS and the mechanism associated with the removal of LAS in CRIS are discussed as well, so as to provide scientific reference and practical technique to the ecological treatment of urban rivers polluted by domestic laundry Wastewater.The results of this system show that the average removal efficiency of LAS, COD, BOD, and ammonia remained at stable levels - despite influent fluctuating with different concentrations - posting removal rates of 99.00%, 79.8%, 72.5%, and 90.88% respectively. No remarkable influence of domestic laundry Wastewater was observed on the pH, Eh, Total Nitrogen and organic matter of the upper level of the soil. The amount of organic matter at the lower level of the soil however decreased significantly.This contribution to the removal efficiency of LAS is a combination of three factors and includes the way the system works, the composition of the artificial soil and the depth of soil. The mechanism involves the creation of alternate aerobic environment and anaerobic environment which are beneficial to biodegradation. The composition of the artificial soil is the most important factor to the stability of the system. The depth of soil will influence the efficiency and the economy of the system. The main removal mechanism of LAS in a constructed rapid infiltration system is its adsorption to the constructed soil and the degradation of microorganisms.