Keberkesanan Saliran Berumput dari segi Pembuangan Pencemaran dan Kadar Penyusupan

Abstract

Swale drainage is a broad and shallow drainage that is able to filter runoff before flowing to the main drain and river. This study is focused on the effectiveness of the swale drainage compared to concrete drainage, in terms of pollutant removal and its relationship with the infiltration rate. The chosen site is at Astaka field, in Selangor.The water quality of the outflow was tested to determine the water quality classes when compared to the Interim National Water Quality Standards (INWQS) for Malaysia. Chemical oxygen demand (COD), total suspended solid (TSS), ammonia nitrogen, pH and turbidity are the five parameters that were tested in the water quality test. The study of infiltration rate of swale outflow was done by using the Mini Disk Infiltrometer and was compared with that of the field without swale. Swale proved to be effective to remove about 40%-60% TSS, 10-70% COD and 30-80% ammonia nitrogen compared to the regular concrete drain. The water turbidity of the outlet is higher than that of the inlet for both types of drainage. Results show that swale has negligible effects towards the pH value. The pH value obtained shows signs of alkalinity of the water outflow. The water quality of the outflow at swale outlet achieved Class II according to the INWQS for Malaysia. Swale at Astaka field had a rate of infiltration of 1.8-2 cm/hour which indicates a smaller rate than the field without swale.