Method for treating excess sludge

Abstract

The invention discloses a method for treating excess sludge. The excess sludge is dried by utilizing sintering flue gas which is discharged in a metallurgical sintering process and has higher temperature. The method specifically comprises the following steps of: feeding excess sludge to be treated which has the water content of between 80 and 90 percent into a plate and frame filter press, dehydrating under the pressure of between 25 and 45MPa to obtain a filter-pressed dehydrated sludge cake with the water content of between 40 and 55 percent, feeding the sludge cake into a sludge granulation device to crush into coarse particles with the particle size of about between 3 and 5mm, introducing the particles into a thermal energy drying room, introducing flue gas which is discharged in the metallurgical sintering process and has the temperature of between 100 and 180 DEG C into the thermal energy drying room, and drying the sludge particles, wherein the calorific value of the dried sludge is 2,000 to 4,000 kilocalories and the water content is 5 to 10 percent. The method has the advantages that: the waste heat in the sintering flue gas in iron and steel metallurgical industry is effectively utilized, the dehydration of the excess sludge is reduced, the excess sludge with a higher calorific value is taken as fuel to be added into a sintering working procedure, and the final treatment of the excess sludge is realized.

Description

technical field [0001] The invention relates to the field of excess sludge treatment and disposal, in particular to a treatment method for excess sludge combined with a metallurgical sintering process. Background technique [0002] Residual sludge is the solid sediment produced in the process of sewage treatment, which contains a large amount of water, inorganic ash and organic volatiles. With the development of social economy and urbanization in our country, the generation and quantity of urban sewage are constantly increasing. At present, there are more than 500 urban sewage treatment plants in operation across the country, with an annual treatment capacity of 11.36 billion m 3 . According to relevant predictions, the amount of urban sewage in my country will increase significantly in the next two decades, and the amount of sewage discharged by the end of 2010 will reach 440×108 m 3 / d; in 2020, the sewage discharge volume will reach 536×108 m 3 / d. The improvement of...

AI Technical Summary

Problems solved by technology

If the remaining sludge is not properly treated and disposed of, it will not only occupy a large amount of land, but also cause secondary pollution to the environment and become a major public hazard affecting urban environmental sanitation.

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