CN102815853A

CN102815853A - Harmless mud processing method for sewage treatment plant

Info

Publication number: CN102815853A
Application number: CN2011101553361A
Authority: CN
Inventors: 黄澄华; 叶旭; 李菁; 吴�荣; 陈雪娟
Original assignee: 湖北中科博策新材料研究院
Priority date: 2011-06-10
Filing date: 2011-06-10
Publication date: 2012-12-12

Abstract

Disclosed is a harmless mud processing method for a sewage treatment plant. The method comprises that a water retention material is added based on primary mud, the water content of a mud sample is lowered to below 65%, the a cementitious material is added and mixed, the mixture is stirred and mixed evenly and air dried naturally under normal temperature and pressure, and during mixing, the quality ratio of the mud, the cementitious material and the water retention material is 100:(15-30):(0.01-0.05). The method has the advantages that after the mud is processed, the obtained modified material coats harmful bacteria and noxious heavy metals in the mud, such as chromium, lead and mercury, some industrial gypsum such as fluorine gypsum, phosphorus gypsum, titanium dioxide gypsum and desulfurized gypsum has rich malysite, the industrial gypsum and noxious metal elements are subjected to oxidation reaction or reduction reaction, then the toxicity of the mud is reduced, the noxious metal elements can be converted to metal elements with an innoxious valence state, the cementitious material is in the alkali environment, some metals are subjected to complexation easily, indissoluble subsulfate can be produced, and simultaneously, growth and propagation of bacterium can be inhibited effectively under alkali environment.

Description

The sewage treatment plant sludge harmless treatment process

Technical field

The present invention relates to the offal treatment technical field, a kind of specifically sewage treatment plant sludge harmless treatment process is specially adapted to comprise that sewage and industrial sewage handle the mud of residual toxic heavy metal in back and bacterium.

Background technology

The important source of urban environment problem is life and trade effluent, and the mud that left behind after disposing of sewage becomes the major hidden danger of urban environment.Mud belongs to solid waste; Stipulate according to " the People's Republic of China's noxious waste pollution environment is prevented therapy ": fully rationally to utilize solid waste and harmlessness disposing solid waste is principle; Encourage, support to carry out cleaner production, reduce the generation of solid waste; Encourage, support utilize resources synthetically, solid waste is carried out making full use of recovery and rationally utilizing.

The domestic and international at present method to sludge disposal mainly concentrates on: arable land method, mud landfill and sludge incineration.Perhaps there is secondary pollution hidden danger in these methods, perhaps take valuable land resources, and perhaps existence needs drawbacks such as huge cost and operation investment cost.

Owing to contain the essential main nutrient composition of plant-growths such as nitrogen, phosphorus, potassium and the organism of the various trace element and the structure of improving the soil in the mud; The U.S., Canada, Britain, France, Holland, Denmark and Sweden all mainly study and make land used plough method; The land used method of ploughing is handled mud does not need dehydration; Utilize pipeline that mud is sent into the place and get final product, total expenses reduces more than 2/3 than combustion method, but after this method of U.S.'s life-time service; Discovery all has very big potentially dangerous to underground water, atmosphere, has begun to limit the use of.

The mud of industrial effluent treatment plant is because of containing heavy metal ion and the pathogenic bacteria that plant and soil is had harm, finally can only be with landfill, to burn be main.Though burning is better to the minimizing and the stability effect of mud, has problems such as energy expenditure is big, secondary pollution is serious; And the toxic substance in the mud and metals ion have not only taken the big area soil behind the landfill, and be expensive high, and caused large-area environmental pollution.

Summary of the invention

The objective of the invention is to study a kind of poisonous and harmful heavy metallic ion and the pathogenic bacteria that can handle in the mud, and effectively utilize nitrogen in the mud, phosphorus, potassium element sewage treatment plant sludge harmless treatment process as vegetable fertilizer.

Sewage treatment plant sludge harmless treatment process of the present invention, its step is following: on the primary sludge basis, add water-keeping material, the water cut of mud is reduced to below 65%, mix consolidating material outward then, evenly puddle at normal temperatures and pressures, natural air drying; Mass ratio when said three mixes is a mud: consolidating material: water-keeping material=100:15～30:0.01～0.05.

Said water-keeping material is water-holding slow-release agent or high multiple water-absorbing resin, for example polyacrylate(s), acetate ethylene copolymer class, polyurethanes, polyethylene oxide class; Create the high multiple water-absorbing resin that Science and Technology Ltd. provides like city far away, Wuhan.

Said consolidating material is to be major ingredient (comprising phosphogypsum, sulphur gypsum, fluorgypsum, titanium white gypsum, phosphorus molybdenum gypsum) with the industrial gypsum; Be aided with cement clinker, metallurgical industry alkaline ash, Water Quenching Slag, power sector flyash, setting accelerator etc. (applicant has with reference to record, and its application number is 200710052700.5) in " the AHF industrial residue---the fluorgypsum modification prepares environmental protection and energy saving building base material and technology " invention application of submitting on July 11st, 2007.Consolidating material each component weight percent is: industrial gypsum 50～80%; Cement clinker 5%～20%, alkaline ash 5～15%; Water Quenching Slag 10～20%; Flyash 5～15%; Setting accelerator 0.5～3%.Described setting accelerator is vitriolate of tartar, sodium sulfate, Tai-Ace S 150.Described industrial gypsum can also be phosphogypsum, desulfurated plaster, titanium white gypsum etc. except that fluorgypsum.

With industrial fluorgypsum is the method that example prepares consolidating material, and its step is following:

(1) the building materials weight percentages is: fluorgypsum 50～80%, cement clinker 5%～20%, alkaline ash 5～15%, Water Quenching Slag 10～20%, flyash 5～15%, setting accelerator 0.5～3%; Above-mentioned each weight percentages of components sum is 100%;

(2) with the AHF reaction process tailings---the fluorgypsum neutralizing treatment is to PH＞7, and is subsequent use as main raw material to feed bin;

(3) cement clinker, alkaline ash, Water Quenching Slag, flyash to feed bin are subsequent use;

(4) above-mentioned each raw material is got into the hot-air seasoning device through the automatic gauge spiral by proportioning and remove surface water entering blending bun;

(5) after the oven dry, compound gets into shredder, is ground to fineness＞200 orders;

(6) compound after the grinding adds setting accelerator, gets into the powder mixer and puddles evenly, promptly becomes the required consolidating material of sludge modification among the present invention.

The advantage of sewage treatment plant sludge harmless treatment process of the present invention is: mud promptly has physical strength preferably after treatment behind the seasoning 24h, just can transport behind the 48h, and physical strength reaches peak value after 28 days.What obtain has material modifiedly not only coated deleterious heavy metal and germs such as the chromium in the mud, lead, mercury; On the other hand; Contain abundant molysite in some industrial gypsum such as the titanium white gypsum (the burning waste residue that can add sulfuric acid industry for the industrial gypsum that does not contain molysite); Can toxic heavy metal be changed into low toxicity or nontoxic through oxidation or reduction reaction; Make deleterious hexavalent chrome reduction become nontoxic trivalent chromium like low price iron, the high price molysite can make highly toxic trivalent arsenic be oxidized to the pentavalent arsenic of low toxicity; Moreover, because consolidating material is alkaline environment, can make the salt complexing of toxic metal element become to be insoluble in the double salt of water; Because bacterium is prone in sour environment, grow up and breeding, and consolidating material of the present invention is alkaline PH＞9, is unfavorable for even can effectively suppresses the growth of bacterium, adds to coat and consolidation, finally reaches bacterial reproduction even the dead effect of suppressing; Ready-made material modified when the soil modifier; Can absorb and discharge moisture content gradually with the variation of surrounding environment; Drought resisting and anti-ponding are had certain effect, and great number of organic matters such as abundant nitrogen, phosphorus, potassium can play the effect of chemical fertilizer in the mud, benefit crop growth; It solidifies its physical strength of back and significantly improves, and can produce certain economic benefits as material of construction.

Embodiment

Embodiment one

1, preparation consolidating material, its step is following:

2, get four parts of sewage work's primary sludges (water cut is 78%) 100g, four parts high multiple water-absorbing resins (more than 1000 times) 0.02g drops to below 65% sludge moisture content; In above four groups of materials, add self-control consolidating material 15g, 20g, 25g, 30g more respectively; Agglomerating after stirring, observe in room temperature held 48h, possessed physical strength preferably; Physical strength reaches optimum regime after 28 days completely solidified, and following table is the compression strength value behind curing 48h and the 28d.

Table one consolidating material ratio is to the influence of material modified ultimate compression strength

Show that through experiment along with the increase of the per-cent of consolidating material, its ultimate compression strength strengthens gradually, but just be equipped with intensity after adding 15% consolidating material air dry 48h, intensity reaches the highest after 28 days completely solidified, can substitute some material of construction.And do not have requirement of strength when the soil modifier, so select for use 15% consolidating material can significantly reduce the cost that sewage sludge harmlessness is handled.

3, primary sludge and the mud that coated with consolidating material (etc. quality primary sludge make) are soaked in the water of equal volume simultaneously (Bacteria Detection is that leach liquor is cultivated detected result behind the 24h in incubator), table two, table three be respectively heavy metal and mikrobe leaching experiment result:

Table two heavy metal leaching experiment

Unit: mg/litre

Table three microbe leaching experiment

Unit: individual/gram

Through above heavy metal and mikrobe leaching experiment; Each item leaches has obvious reduction than primary sludge, and along with the prolongation of soak time, it is less that it leaches concentration change; Content of microorganisms even the trend of reduction is arranged wherein; Minimum for mud after the modification 30 times of primary sludge total plate count are to the maximum more than the thousands of times, prove absolutely sewage treatment plant sludge harmless treatment process of the present invention not only can with the heavy metal ion in the mud and some bacteriums be coated on material modified in; Even can effectively eliminate some bacterium, effectively solve the serious harm that residual mud causes environment after the WWT.

4, be immersed in the water material modified, treat to claim to such an extent that water regain is 29.6% after its constant weight, be positioned over 48h under the sunshine again; Dehydration 29.3%, primary sludge be dehydration 78% fully then, regulates oven temperature simulating drought condition; Material modifiedly continue dehydration 8.3%, and the primary sludge constant weight is constant.Through tests such as suction, dehydrations, material modified certain water retaining function that possesses is described, water-retaining capacity can reach 40.3%, and having verified material modifiedly has certain resistance ability to ponding and damage caused by a drought when the soil modifier.

5, primary sludge is through harmless treatment, and when the splicing material that adds 30%, spontaneous curing 28 its physical strengths of back reach peak, can in more environment-friendly energy-saving building materials fields, be applied, and the result is following for its mechanical strength test:

Table four physical strength detects

Embodiment two

A kind of sewage treatment plant sludge harmless treatment process, its step is following: on the primary sludge basis, add water-keeping material, the water cut of mud is reduced to below 65%, mix consolidating material outward then, evenly puddle at normal temperatures and pressures, natural air drying.

Mass ratio when said three mixes is mud (water cut 95%): consolidating material: water-keeping material=100:15～30:0.05.

Said water-keeping material is that the high multiple water-absorbing resin that Science and Technology Ltd. provides is created in city far away, Wuhan.

Said consolidating material is to be major ingredient with industrial fluorgypsum, is aided with cement clinker, metallurgical industry alkaline ash, Water Quenching Slag, power sector flyash, setting accelerator etc.Consolidating material each component weight percent is: fluorgypsum 50%; Cement clinker 10%, alkaline ash 12%; Water Quenching Slag 15%; Flyash 10%; Setting accelerator 3%.Described setting accelerator is vitriolate of tartar, sodium sulfate, Tai-Ace S 150.

(1) the building materials weight percentages is: fluorgypsum 50%, cement clinker 10%, alkaline ash 12%, Water Quenching Slag 15%, flyash 10%, setting accelerator 3%;

Embodiment three

The sewage treatment plant sludge harmless treatment process, its step is following: on the primary sludge basis, add water-keeping material, the water cut of mud is reduced to below 65%, mix consolidating material outward then, evenly puddle at normal temperatures and pressures, natural air drying;

Mass ratio when said three mixes is mud (water cut 70%): consolidating material: water-keeping material=100:15～30:0.01.

Said water-keeping material is polyacrylate(s), acetate ethylene copolymer class.

Said consolidating material is to be major ingredient with the industrial gypsum, is aided with cement clinker, metallurgical industry alkaline ash, Water Quenching Slag, power sector flyash, setting accelerator etc.Consolidating material each component weight percent is: phosphogypsum 73.5%, cement clinker 5%, alkaline ash 6%, Water Quenching Slag 10%, flyash 5%, setting accelerator 0.5%.Described setting accelerator is vitriolate of tartar, sodium sulfate, Tai-Ace S 150.

With industrial phosphogypsum is the method that example prepares consolidating material, and its step is following:

(1) the building materials weight percentages is: phosphogypsum 73.5%, cement clinker 5%, alkaline ash 6%, Water Quenching Slag 10%, flyash 5%, setting accelerator 0.5%;

(2) with the phosphogypsum neutralizing treatment to PH＞7, subsequent use as main raw material to feed bin;

The invention is not restricted to the foregoing description, the mass ratio that adds according to water-keeping material and consolidating material and each component of consolidating material different can be formed a plurality of embodiment, and all fall within protection scope of the present invention.

Claims

1. sewage treatment plant sludge harmless treatment process; It is characterized in that: its step is following: on the primary sludge basis, add water-keeping material; The water cut of mud is reduced to below 65%, mixes consolidating material outward then, evenly puddle at normal temperatures and pressures, natural air drying.

2. sewage treatment plant sludge harmless treatment process according to claim 1 is characterized in that: the mass ratio when said three components are mixed is a mud: consolidating material: water-keeping material=100:15～30:0.01～0.05.