Optimal Allocation of Waste Loads in a River with Probabilistic Tributary Flow under Transverse Mixing

• Published in: Water environment research Vol. 71; no. 2; pp. 156 - 162
• Main Authors: Li, Shiyu, Morioka, Tohru
• Format: Journal Article
• Language: English
• Published: Alexandria, VA Water Environment Federation 01.03.1999; Blackwell Publishing Ltd
• Subjects: Applied sciences; Continental surface waters; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Flow velocity; Freshwater; Hydrology; Hydrology. Hydrogeology; Natural water pollution; Pollution; Pollution load; Pollution, environment geology; PROBABILISTIC RIVER QUALITY MANAGEMENT; Quality management; Research Papers; River basins; River water; Stream flow; TRANSVERSE MIXING; Tributaries; Waste load; WASTE LOAD ALLOCATION; Wastewater treatment; Water pollution; Water quality; Water treatment and pollution; Hydrology; Probabilistic approach; Pollutant behavior; Surface water; Water quality; Fresh water discharge; Water pollution; Effluent discharge permit; Waste water discharge; Modeling
• ISSN: 1061-4303; 1554-7531
• DOI: 10.2175/106143099X121472

A model is proposed for the optimal allocation of waste loads in a river basin, taking into account transverse mixing resulting from the confluence of tributaries with different pollutant levels and the variation of river flow rates. The model is stated as the minimization of cost of wastewater treatment in the whole river basin, subject to the satisfaction of environmental standards imposed for the river quality at water intakes along the river. The flow rate of the river system is regarded as a random variable in the model and constraints on water quality levels are expressed in a probabilistic form. The model is applied to a river with three tributaries joining at one point. The frequency of flow rate of the river system is approximately represented by that of flow rate groups obtained by using statistical methods. Results of the model application show that the priority of wastewater treatment shifts from one tributary subbasin to another when environmental standards are changed, reflecting the effect of transverse mixing in the mainstream. Water quality violations caused by flow rate groups are discussed in the study.