CN102153258A - Production technique for reducing content of heavy metals in municipal domestic sludge - Google Patents

Abstract

The invention relates to a production technique for reducing the content of heavy metals in municipal domestic sludge. The method is realized in a way that: municipal domestic sludge is changed into harmless substances by one-step high-temperature fermentation treatment, and the physical and chemical properties of the sludge are improved, so that the sludge is suitable for plant growth; plants capable of enriching overproof heavy metal elements are grown on the sludge, so that heavy metals in the sludge are transferred into plants, thereby obviously reducing the content of the heavy metals in the sludge, until the sludge achieves the quality standard for organic fertilizer; and the sludge is used as a material for producing organic fertilizer. The invention has an active meaning in promoting the city to treat domestic sludge and reutilize soil in a safe way.

Description

Municipal sludge heavy metal minimizing production technique

Technical field

The present invention relates to the minimizing recovery technique that a kind of municipal sludge heavy metal content surpasses the fertilizer quality standard, be specially adapted to solve municipal sludge composting safe utilization problem.

Background technology

Municipal sludge is the waste of city domestic sewage treatment plant, contains abundant N, P, K and organic matter, is good organic fertilizer resource.On agricultural, rationally utilize mud significant to pressure, minimizing energy consumption, reduction agriculture production cost, minimizing pollution by chemical fertilizer, increase organic fertilizer resource, maintenance soil fertility, the realization sustainable development of reduction chemical fertilizers production.Because mud contains many pollutents, as heavy metal, toxic organic compound and harmful organism, influence production, output, the quality of farm crop, can accumulation in soil, polluted underground water or crop, enter food chain, be detrimental to health.Therefore, the mud of Sewage Plant must be dealt carefully with, and carries out just making full use of after the harmless treatment according to the mud situation simultaneously.

Along with China's city domestic sewage quantity discharged increases year by year, whole nation quantity of wastewater effluent in 2006 reaches 29,700,000,000 tons at present, 1,782 ten thousand tons of year mud generations.It is strict day by day that sharply increase and the environmental protection of municipal sludge made laws, and makes the appropriate disposal of mud become the task of top priority.The method of disposal of mud has agricultural use, sanitary landfill, burning etc.Mud is agricultural in these methods has been proved to be the most economically viable, and the processing capacity is big, and is the good method of resource reutilization, paid attention to by various countries.But in the mud chemical pollutant content especially heavy metal content generally exceed standard, limited agriculture direct utilization, utilization ratio is usually less than half of mud total amount.China also can't realize the agriculture industrialization utilization of mud at present.A large amount of like this mud can only be disposed by additive method, and both contaminate environment was wasted resource, expended a large amount of disposal costs again.

Summary of the invention

The object of the present invention is to provide a kind of municipal sludge heavy metal minimizing production technique, this method is handled municipal sludge and is realized that health is innoxious by a thermophilic fermentation, and the physicochemical character of improvement mud, be fit to plant growth, then, plantation has the crop to the heavy metal element accumulation ability that exceeds standard on mud, the heavy metal of mud is transferred in the plant, make that heavy metal content significantly reduces in the mud, until the quality standard that reaches organic fertilizer, raw materials for production as fertilizer utilize then, have positive effect to promoting solution domestic sludge soil, city safety to utilize again.

Technical program of the present invention lies in: a kind of municipal sludge heavy metal minimizing production technique is characterized in that: carry out according to the following steps:

1) 3 ~ 5 parts of municipal sludges is mixed for 1 part by a certain percentage with agricultural organic waste, make that the C/N of mixture is 30 ± 5, pH value 6.0 ~ 7.5, water ratio 60% ~ 70%;

2) the said mixture material stirs, and with forklift it is sent into the windrow groove and builds heap;

3) forced ventilation in the windrow groove, and under aerobic fermentation condition, make the windrow temperature remain on 60 ℃ ± 5 ℃, kept 7 ~ 10 days;

4) mud after the pyroprocessing is delivered in the arable land, stacked 50 ~ 60cm, plantation heavy metal accumulation crop on mud, after heavy metal is absorbed by crop, after its content is reduced to the quality standard of organic fertilizer, it as the organic fertilizer production prepared using, is guaranteed mud arable land safe utilization.

The invention has the advantages that: 1, the present invention is easy and simple to handle, treatment effect good, and the main heavy metal content of the mud after the processing all can reach the agricultural national standard of mud;

2, adopt the method for plantation heavy metal accumulation crop to reclaim heavy metal, be a kind of environment amenable treatment process, but be the well behaved biodegradable treatment process of a kind of enrichment various heavy or multivalence heavy metal;

3, the plant after the plantation is optionally used as the feed of livestock industry, simultaneously also can with the additive method coupling, as traditional method couplings and integrated such as chemical extraction and microorganism leachings.

Description of drawings

Fig. 1 is a schematic flow sheet of the present invention.

Embodiment

A kind of municipal sludge heavy metal minimizing production technique, at first the ratio that municipal sludge and other agricultural organic waste are joined 1 part of agricultural organic waste in per 4 parts of domestic sludges is mixed, added agricultural organic waste can be the remaining stalk in results back, rural area, the straw slag, husk or animal excrement etc., the C/N that makes mixture is 30 ± 5, pH value 6.0-7.5, water ratio is 60%-70%, after then will cooperating material and high-temperature aerobic actinomycetes to stir, be sent to the windrow groove with forklift and build heap, then, using forced ventilation makes windrow keep certain oxygen concn, for the high temperature bacterium is created quick growth conditions, aerobic bacteria reproductive process decomposing organic matter also releases energy windrow is constantly heated up, and under ventilation condition, make windrow keep 60 ℃ ± 5 ℃, the about 7-10 of thermophilic fermentation days, for aerobic microbiological is created favourable growth conditions, make organic floculants such as gathering propionic acid amide in the mud by microbiological degradation, lose viscosity, improve the physical behavior of mud, help plant growth, simultaneously, 60 ℃ ± 5 ℃ material high temperature of maintenance in 7-10 days, also favourablely kill pathogenic bacteria and sick worm's ovum in the mud, realize that health is innoxious.

Then, mud after the pyroprocessing is delivered to the arable land, stack about 50cm, the enrichment crop of plantation heavy metal on mud, reduce to the quality standard of organic fertilizer until heavy metal content after, as the organic fertilizer production prepared using, can solve municipal sludge arable land safe utilization problem, contain the high crop of heavy metal content and can be used as the livestock and poultry cultivation feed.

In sum, municipal sludge heavy metal minimizing production technique of the present invention has convenient enforcement, can effectively reduce heavy metal content contained in the municipal sludge, has stronger promotion prospect.

The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to covering scope of the present invention.

Claims (2)

1. municipal sludge heavy metal minimizing production technique is characterized in that: carry out according to the following steps:

1) 3 ~ 5 parts of municipal sludges is mixed for 1 part by a certain percentage with agricultural organic waste, make that the C/N of mixture is 30 ± 5, pH value 6.0 ~ 7.5, water ratio 60% ~ 70%;

2) the said mixture material stirs, and with forklift it is sent into the windrow groove and builds heap;

3) forced ventilation in the windrow groove, and under aerobic fermentation condition, make the windrow temperature remain on 60 ℃ ± 5 ℃, kept 7 ~ 10 days;

4) mud after the pyroprocessing is delivered in the arable land, stacked 50 ~ 60cm, plantation heavy metal accumulation crop on mud, after heavy metal is absorbed by crop, after its content is reduced to the quality standard of organic fertilizer, it as the organic fertilizer production prepared using, is guaranteed mud arable land safe utilization.

2. municipal sludge heavy metal minimizing production technique according to claim 1 is characterized in that: described agricultural organic waste is stalk, straw slag, husk, animal excrement.

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