[Determination of the design parameters for making urban wastewater plants in cold regions of Iran]

ABSTRACT

Indicating the quantities and qualitative characteristics of raw wastewater entering treatment plant is one of the basic fundamentals of correct1 designation of treatment plants. The purpose of this study was to determine the design parameters for making urban treatment plants in cold regions of Iran. This applicative research is based on empirical studies which have descriptively been done in a temporal manner. In this study, three wastewater plants were selected as pilot from cold regions of Chaharmahal va Bakhtiari province i.e. Shahrekord, Broujen and Farsan wastewater plants. The quantative and qualitative characteristics of waste water entering to these wastewater plants were analyzed in a one-year period. In this research as well as measuring the waste water flow entering the plant the temperature, PH in entrance, chemical oxygen demand [COD], 5-days Biochemical oxygen demand [BOD5], suspended Solids [TSS], volatile suspended solids [VSS], Kajaldal Nitrogen [TKN] and phosphate phosphorous [P] were measured in 24-hours compound samples proportional to the wastewater flow. Data were analyzed using t-test and ANOVA. The final results of the research parameters in cold weather regions for BOD5, COD, TSS, VSS, TKN and P has daily been 41, 60, 65, 47, 8.3, and 0.93gr per capita. Average production of wastewater was found 177 liter per capita per day. The obtained results from Max and Min wastewater flow coefficient were 1.76 and 0.29, respectively. No significant differences were found for BOD5, COD, TKN and P between three wastewater plants, but TSS, VSS were significantly higher in Shahrekord [P<0.05]. In the case of using design parameters based on different climates and real characteristics of waste waters, we can obtain higher efficiency in guidance of exploitation from wastewater plants. In order to design plants in cold weather regions like Shahrekord [and most cities in the west of Iran] it is recommended that the per capita production and other design parameters to be considered in the trust range of this research