Investigation Self-purification and simulation of nitrogen and phosphorus changes along the Abbas Abad River of Hamedan using QUAL2KW

River Qualitative conservation requires additional investment to create wastewater collection and treatment systems and may also limit the development of activities in the river basin. In this study, the self-purification capacity of Abbas-Abad river of Hamadan using QUAL2KW model and the parameters NH4, NO3 and PO4 were evaluated in two longitudinal interval (Agriculture and Drinking) of the river periods in 2011-2012 and 2015. Self-purification model of the river was determined by inserting qualitative and quantitative data retrieved from the stations, and the entering wastewaters were created and calibrated. The results showed that the highest amount of self-purification of N-NH4 parameter in the Agriculture interval in 2015 is equivalent to 54%. Parameter for the N-NO3 and P-PO4 parameters, the highest rate of self-purification capacity is in the Drinking interval in 2015 and is 29% and 38%, respectively. The amount of P-PO4 has grown steadily along the river. The best modelling for P-PO4 parameter was related to 2011 and 2012 with a standard error of 0.02.