Evaluation the Correlation between Turbidity and Total Suspended Solids with other Chemical Parameters in Yazd Wastewater Treatment Effluent Plant

Introduction: Expensive chemical tests are usually applied to control the efficiency of wastewater treatment plants. However, the cost of measuring these parameters is one of the challenges of the wastewater treatment plants. Using statistical methods has been evaluated for possibility of calculating expensive parameters by measuring the inexpensive parameters in this study. Materials and Methods: Initial sample number in this study was 87 cases that were collected from SBR effluent treatment plants of Yazd as a routine sampling for two years in March 2013 to March 2015. Total suspended solids (TSS) and turbidity parameters were defined as independent variables and twelve parameters including BOD5, COD, TKN, NH3+, NO3-, NO2-, TP, TH, Ca2+, Mn2+, alkalinity, and color were the dependent variables. Spearman test was used to investigate the significant relationship between independent and dependent variables. Linear regression analysis was used to determine the linear equation between TSS and turbidity as independent variables with BOD5, COD, TKN, NH3-, NO2-, TP and color as dependent variables. Results: The results of the regression equations in relation to turbidity and TSS with independent variables showed that the R value for color, TKN, NH3+, BOD5, COD, TP, and NO2- were 0.942 , 0.931 , 0.91 , 0.905 , 0.874 , 0. 872 and 0.86 respectively from the highest to the lowest. Conclusion: The measured values of BOD5, COD, TKN, TP, NO2-, NH3+, and color in laboratory were very close to those predicted through regression equations. Therefore, regression equations created in this study can be used to calculate expensive parameters.