Method for preparing haydite by sintering urban domestic sewage sludge

Abstract

The present invention relates to solid waste treating technology, and discloses sewage sludge treating and utilizing process. Sewage sludge in over 70 %, fly ash and clay as the material are treated through drying, crushing, mixing, press forming, preheating and roasting to obtain haydite product. The roasted haydite has one compact glaze layer in the surface and great amount of inside pores, and possesses compressive strength, water absorption, environment safety, etc reaching relevant standard. Using sewage sludge in making building material is significant.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment and disposal, and in particular relates to a method for making ceramsite by sintering urban sewage sludge for harmless, reduced and resourceful sludge. Background technique [0002] At present, the urban sewage treatment rate in my country is 42%, and the annual discharge of sewage sludge is about 1.3 million tons (dry weight), and the annual growth rate is greater than 10%. If all urban sewage is treated, the annual sludge output will reach 8.4 million tons (dry weight), accounting for 3.2% of my country's total solid waste. In addition to inorganic matter and organic matter, sludge also contains a large number of toxic and harmful substances such as germs, parasites, and heavy metals. Improper treatment can easily cause serious secondary pollution. Therefore, the way out to solve a large amount of urban sewage sludge is to find a method to make the sewage sludge harmless, reduce a...

AI Technical Summary

Problems solved by technology

At present, the disposal of urban sewage sludge in my country is limited to landfill, incineration, composting and other methods, but these methods have certain disadvantages: landfill is used in most areas of my country to dispose of sludge, but with the increase of sludge volume At the same time, municipal construction is rapidly occupying available land resources, making it difficult to select a large area of ​​landfill

In addition, because the moisture content of the sludge entering the landfill in my country often does not meet the specified requirements, this has brought many problems to the operation and management of the landfill. Many landfills have begun to refuse dehydration with a moisture content of 75% to 80%. sludge entry

However, incineration treatment is only used in a small amount in some economically developed areas due to its high cost.

The traditional composting process is gradually eliminated due to its large area, long cycle, poor fertilizer quality, and easy to produce odor. The new composting process is only used in the United States, due to the high investment in equipment such as mechanical ventilation and high-temperature aerobic fermentation. Japan, Europe and other developed countries have been well used, but in my country, because domestic sewage is often mixed with industrial sewage, the heavy metal content in the sludge is usually high, so that the heavy metals in the composted fertilizer exceed the standard and further limit its application.

[0004] The use of domestic sewage sludge to manufacture building materials is an emerging method of sludge disposal and resource utilization in recent years. It is an important way to solve the growing amount of sewage sludge. However, the existing technology has a low sludge mixing ratio and requires a large amount of Clay and shale resources and other issues make it difficult to achieve large-scale application

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