INVESTIGATION ON THE BIODEGRADATION CAPACITY OF URBAN RIVERS IN JAKARTA, INDONESIA

Abstract

Jakarta is a city with dense population and various activities causing the heavy pressure to the environment. Domestic and non-domestic activities are generating pollution to its rivers. The water body actually has itself a self natural purification capability. The characteristic of the river water quality will affect this pollution degradation process. This research is conducted to examine the biodegradation capacity of Jakarta’s rivers. Water quality data of 23 rivers were collected for the time period of 2011 to 2015. Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) concentrations are then being used to calculate the BOD/COD ratio. The calculation results show that during the period time of 2011-2013 the ratio ranges between 0.36 and 0.63, which indicates that the rivers have average biodegradation capability. However, the 2014 year’s data show that almost all of the rivers have ratio less than 0.2, indicating the nobiodegradation capability. Existence of metals can also inhibit the biodegradation process. The water quality data shows significant increase of metals in the year of 2014, especially Copper and Zinc in several rivers.Surfactant was also observed in extremely high concentration. Thus, most of the Jakarta’s rivers have relatively low capability in biodegradation capacity and self purification capability. Although the latest year data shows an improvement, yet the BOD/COD ratio is still in the range of slow of biodegradation capacity.