Simulation of water quality parameters from the treatment of wastewater using stabilization ponds (Case study: Tehran wastewater stabilization pond)

Today, discharging the wastewaters into the river is the main factor of water pollution and associated with environmental impacts. There are several methods for wastewater treatment. The natural ways like wastewater stabilization pond (WSP) is apply in a lot of countries especially in under developed countries because no needed to high technology. The WSP’s are suitable for wastewater treatment in small societies and some special industries like slaughterhouse, dairy products and meat products and etc. The advantages of this way are high efficiency in treatment of pathogens, toxic and organic materials. These ponds treat the wastewater naturally by alga and bacterial reactions. Ecological condition and wastewater properties affect the efficiency of WSP. Furthermore the efficiency of WSPs depends to several factors like the temperature, light, alga and bacterial reactions and Etc and must be analyzed before construction. In this regard the quality parameters in Tehran WSP simulated with CE-QUAL-W2. The model has been calibrated and evaluated on the basis of collected data from Tehran WSP and the ability of the model analyzed to optimum the efficiency. Furthermore the concentration trend of parameters analyzes during the day in different hours to determine the effects of solar radiation and the others parameters on them. The results shows BOD concentration increase at noon and decrease at night that shows it depends to solar radiation. Alga also is a function of solar radiation and the concentration increase in noon and decrease in afternoon. The trend of phosphate and nitrate is the same and since these two parameters are used for growth process of algae so in noon decrease and in night increased. Because at night the growth process of algae is limited and no need for phosphate and nitrate exist so the concentration increased. The results of modeling with CE-QUAL-W2 show good agreement between the experiments and the simulation data and CE-QUAL-W2 is a suitable model for analyzing the quality parameters in WSP and can be used for design of new stabilization ponds or for improving the effluent quality of existing ponds.