Sewage Treatment Method and its Role on Wastewater Price: Case Comparison of Sewage Treatment Plants No. 4 and 5 in Mashhad

With the development of industries and agriculture, the issue of water supply and the consequent challenge of sewage is becoming increasingly important. Water recycling and the use of treated sewage is the most desirable option for water supply. Considering the operating costs of modern sewage treatment plants, the economic aspect of the issue should be considered in order to provide treatment costs in addition to the desire of wastewater consumers. In Mashhad, before 2016, all existing sewage treatment plants were stabilized by the traditional method and their treatment costs were not significant. Therefore, most of the sewage received income was spent on developing the sewage collection network. But in 2016, with the opening of two modern treatment plants in Mashhad, with a capacity of 60,000 and 65,000 cubic meters per day, each of which can bring the quality of effluent to standards of discharge to surface water, the issue of sewage price and the total treatment price of each cubic meter of sewage become important. Also, by imposing penalties based on quality parameters, certain subscribers such as restaurants and hoteliers can be directed to pre-treatment before evacuation to the network. In this article, based on the extracted results during one year of operation of these two treatment plants, comparisons have been made in terms of construction costs, operation, consumables, personnel and finally the output of both treatment plants which should introduce the advantages and disadvantages of both methods in terms of ease of operation and economic efficiency and in the construction of treatment plants, the type of treatment method should be selected with more awareness.