Following the increasing growth of population and the reduction of water resources, a huge volume of sludge, which is a subsidiary product of sewage treatment, needs to be disposed safely in order to protect the environment. The aim of the present study is to find an appropriate method for disposal and beneficial application of sludge. Sludge consists of organic materials, nutrients, pathogens, heavy metals, PCBs.... etc. Regarding the sludge produced from Shahrak Qods Treatment Plant using the proposed management plan, after taking several samplings and physical, chemical and pathogenic tests on the sludge, it was determined that according to the US EPA standards and regulations, the resulting sludge holds the qualities of class B pathogenically. Regarding the heavy metals, it also bears an exceptionally excellent quality, while having large amount of organic materials, nutrients and micronutrients, which represents the fertilizer value of this material. In addition, it was known as the best alternative for land application after testing various alternatives of disposal. For this purpose, Mehrshahr Garden in Karaj was chosen as the most suitable location for using sludge class B. Having carried out certain chemical and physical experiments on the collected samples of soil, the rate of sludge loading based on Nitrogen (as the limiting factor of application), as well as, the area of sludge application were estimated. Meanwhile, a comparative cost evaluation, between the use of chemical fertilizer and sludge application was made, regarding the amount of commercial fertilizer in these lands, which at last resulted into the cost- effectiveness of this plan. The preparation of a similar management plan for all treatment plants in the process of design or construction is a necessity, since it is proved that by implementing such a plan, standards and regulations suitable to Iran’s condition, could be imposed for disposal or beneficial application of sludge.
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