Hamidreza Ansari Joveini - Lecturer in the Department of Civil Engineering, ShahidChamranFaculty of Engineering in Rasht
Mohammad Ansari Joveini - Master of Science in Civil Engineering, Road & Transportation - Deputy Chairman of the Board of Directors in GhaemsazanAfra Co.
Mahdi Ansari Joveini - Master of Science in Civil Engineering, Structure - Chairman of the Board of Directorsin GhaemsazanAfra Co.
Mohadeseh Ansari Joveini - Bachelor of Science in Architectural Engineering, Member of the Board of Directors in GhaemsazanAfra Co.

Background & Objective: Determination of quantitative and qualitative specifications of raw wastewater entering the wastewater treatment systems is one of the main elements of their correct design. This study aims to determine the parameters of designing wastewater treatment systems and study their sewage absorption coefficient for temperate regions of the country. Method of Study: In this descriptive – analytical study, two anaerobic and aerobicwastewater treatment systems located in Guilan Province were selected as a pilot in a temperate region and the qualitative and quantitative specifications of the wastewater entering them were investigated in the study period. In addition to the continuous measurement of thewastewater discharge into the system, temperature, PH, chemical oxygen demand (COD), 5- day biochemical oxygen demand (BOD5), and total suspended solids (TSS) were measured in 24-hour compound samples. Findings: The average per capita of parameters under research in this study based on milligrams per liter with industrial-domestic use for every day of production of BOD5, COD and TSS was equal to 90, 346.5 and 59.8 L, respectively and the average production ofindustrial wastewater was 16000 L per day. By comparing the results of per capita parametersin two wastewater treatment systems, a significant difference was determined between BOD5, COD and TSS parameters.Conclusion: Using the designing parameters specific for developed countries for designing awastewater treatment system and absorbing the resulting sewage in cities of Iran is not appropriate. Therefore, it is suggested to use the designing parameters based on different weather conditions and real specifications of wastewaters for increasing the efficiency in theoperation of wastewater treatment systems. Thus, the application of a unit design as anintegrated system can separately reduce the pollution load of each industrial wastewater to the level of environmental standards, and significantly reduces the need for the design andimplementation of a collection network and wastewater treatments. This is more important when the underground aquifers’ level is close to the ground level (temperate and cold regions) and not only the administrative problems resulted from these underground networks, but also the pollution risk of these aquifers is considered.

Wastewater treatment system, temperate region, wastewater discharge, per capita parameters, environmental standards, underground aquifers