Granular bioretention facility medium layer filler prepared from tap water plant residual mud

Abstract

The invention provides a granular bioretention facility medium layer filler prepared from tap water plant residual mud, which not only solves the final outlet problem of the tap water plant residual mud, but also solves the problems of high cost, unstable quality and the like of a bioretention facility growth medium which is most widely used in sponge city construction. The water content of the residual mud dehydrated by the centrifugal machine in the waterworks is about 70%, 0.1-3% of biological curing agent is added when the residual mud is deeply dehydrated until the water content is about 50%, and mixing and stirring are carried out. The uniformly stirred residual mud enters a granulator for granulating, drying is performed again, and bagging is performed when the water content is reduced to 20%. The porosity of the growth medium is greater than 40%, the permeability is greater than 500 mm / hr, and the SS removal rate is greater than 80%; the water retention function is achieved, plant growth is facilitated, and the service life is longer than 5 years.

Description

technical field [0001] The invention belongs to the technical field of environmental protection engineering, and in particular relates to a medium layer filler for a granular biological retention facility made of residual mud from a waterworks. Background technique [0002] More than 90% of the residual sludge (WTR) produced by the waterworks is the by-product of the flocculant rich in aluminum and iron, 24% to 46% of the residual sludge is aluminum, and the rest is sediment, which belongs to general solid waste and is a kind of Relatively clean mud. In recent years, it has been considered as a recyclable substance in the European Union, the United States, Canada and other regions. However, at present, most of the residual sludge produced by domestic waterworks is sent to landfill, which not only takes up valuable land resources, but also cannot meet the requirements of the "Garbage Fill Landfill Mixed Landfill Sludge Standards (GB / T23485—2009) require that transportation ...

AI Technical Summary

Problems solved by technology

At present, constructed wetlands are divided into surface flow wetlands and subsurface flow wetlands. In terms of treatment effect, subsurface flow wetlands are higher than surface flow wetlands, but WTR is almost entirely composed of small clay particles, and its permeability cannot meet the requirements of subsurface flow wetlands. , so it can only be used as a medium for surface flow wetlands, and has certain limitations in wetland applications

[0009] The sixth method is to use WTR as planting soil. Generally, the aluminum content in WTR exceeds the standard for agricultural planting soil, so it can only be used as urban greening soil

After dehydration, this kind of residual mud will form a mud block, and the permeability is almost zero. Generally, it is sent to the solid waste landfill for disposal, which is not only costly, but also a waste of resources.

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