Estimating Point and Non-Point Sources of Pollution in Biñan River Basin, the Philippines

Abstract

A Pollution Load Model was developed for Biñan River Basin, one of the sub-basins of Laguna de Bay, Philippines, to estimate waste loads to surface water by different sources. This model consists of two major elements, a Pollution Load Generation module which quantifies the amount of pollution load at source and a Pollution Load Treatment module specifying the kind of treatment (capacity, efficiency, and location), the output of which is the estimated waste load discharged to the public waters after treatment. The annual waste load at source was estimated at about 9,592 MT for BOD (biochemical oxygen demand). After undergoing purifications or decay processes along the channels and waterways, BOD drops to 66% or 6,388 MT, considered as the annual BOD loading from Biñan River that eventually enters Laguna de Bay. Domestic effluents predicted the highest at 3,850 MT (60%), followed by livestock sources at 1,446 MT (23%). The industrial and non-point sources contribute about 747 MT (12%) and 345 MT (5%) of annual BOD load, respectively. The Pollution Load Model, combined with regular monitoring programs for hydrologic and water quality, provides better understanding on the state of the river system hence, are important evaluation tools for decision making.