An Evaluation of the Importance of Self- Purification Capacity of Rivers in Developing Effluent Discharge Standards

Authors

1 PHD Student of Environmental Planning, Faculty of Environment, University of Tehran

2 Assoc. Prof. Faculty of Environment, University of Tehran

3 Prof. Faculty of Environment, University of Tehran

Abstract

In current effluent discharge standards of the most countries such as Iran, self-purification capacity of rivers
have not been considered. These standards developed a similar effluent discharge standard for all of the rivers
without considering hydrological and hydraulic conditions of rivers.
In this paper in order to show the importance of self-purification capacity and differences between the rivers,
in developing effluent discharge standard, two rivers- Gheshlagh River in Kurdistan and Sabzkooh River in
Chaharmahal Bakhtiari- as samples were selected., and with applying Qual2kw model, current Iran effluent
discharge standards were used to simulate the state of each river. The simulation showed that compliance with
this standard maintain an appropriate qualitative condition of Gheshlagh River but in Sabzkoh River, due to
the large number of pollution sources, these standards not only does not help to maintain the water quality but
will have a very negative impact on water quality. Then Using simulation of river quality, the authorized
appropriate limit based on self-purification capacity and the number and type of pollutants were estimated and
showed that to develop accurate and efficient standards the self-purification capacity, the number of pollution
sources, the amount of waste load and other different conditions of rivers also should be considered.

Keywords