Industrial pollution and the management of river water quality: a model of Kelani River, Sri Lanka

Abstract

Water quality of the Kelani River has become a critical issue in Sri Lanka due to the high cost of maintaining drinking water standards and the market and non-market costs of deteriorating river ecosystem services. By integrating a catchment model with a river model of water quality, we developed a method to estimate the effect of pollution sources on ambient water quality. Using integrated model simulations, we estimate (1) the relative contribution from point (industrial and domestic) and non-point sources (river catchment) to river water quality and (2) pollutant transfer coefficients for zones along the lower section of the river. Transfer coefficients provide the basis for policy analyses in relation to the location of new industries and the setting of priorities for industrial pollution control. They also offer valuable information to design socially optimal economic policy to manage industrialized river catchments.

Challenges in Biodiversity Conservation in a Highly Modified Tropical River Basin in Sri Lanka

“…At least four major municipalities within the Kelani basin discharge untreated or partially-treated sewage and domestic wastewater into the river [27,[54][55][56][57], leading to excessive accumulation of organic waste, which then increases the BOD [58]. Over 6000 industries directly discharge waste into river (Table 1) [9,31,39,59]. The average daily point-source discharge is estimated to be over 414,600 cm 3 , creating a biological oxygen demand in excess of 11,600 kg day −1 [59].…”

“…Over 6000 industries directly discharge waste into river (Table 1) [9,31,39,59]. The average daily point-source discharge is estimated to be over 414,600 cm 3 , creating a biological oxygen demand in excess of 11,600 kg day −1 [59]. Although the focal environmental regulator of Sri Lanka, the Central Environmental Authority, identified these pollution sources decades ago, neither legal nor remedial actions have been taken thus far [31].…”

“…By the year 2000, the growing number of open solid-waste disposal sites have compounded non-point source pollution in Kelani River [27]. The urban runoff contains many biologically hazardous contaminants including heavy and trace metals, oils, and hydrocarbons, an issue well documented in both current (2007) [59] and historical (1985) [61] contexts. Consequently, elevated levels of conductivity (0.006-0.009 Sm −1 ), chemical (11.8-19.4 mg L −1 ) and biological (1.7-2.9 mg L −1 ) oxygen demand, and total coliform bacteria (30,600-51,000 cells 100 mL −1 ) were recorded at both industrial and residential reaches of the Kelani River, while certain urban reaches failed to meet drinking-water quality standards [57,64].…”

Toxic hazards of industrial waste receiving canal system in the lower catchment of Kelani River basin, Sri Lanka

“…In an integrated model simulation on Kelani River pollution carried out by Gunawardena et al (2017), the estimated transfer coefficients revealed that industrial parks have a considerably higher impact across all identified zones in the river basin although these parks generally comply with existing effluent concentration standards. In a biomarker assessment study, Ruvinda and Pathiratne (2018) found neurotoxic, genotoxic and liver histopathological effects in the fish Nile tilapia, Oreochromis niloticus after short term laboratory exposure to the water samples from the confluence of Manikagara Ela and Maha Ela.…”

“…In the proposed 'multistakeholder strategy and action plan for management and conservation of the Kelani River basin 2016-2020', the importance of pollution impact assessments has been emphasised (Mallawatantri et al, 2016). A large number of industries including several export oriented industrial parks are located in close vicinity of Kelani River (Gunawardena et al, 2017). The industries located in these industrial zones/parks are required to treat their wastewater chemically in in-house treatment plants until specified national tolerance limits (Anonymous, 2008) are met.…”