The biochemical processing method of middle-size and small-size wastewater of starch factory
Technical field
The present invention relates to a kind of wastewater treatment method, particularly relate to a kind of biochemical processing method of middle-size and small-size wastewater of starch factory.
Background technology
Starch is a kind of important industrial raw material, except that edible and processed food, is applied to industries such as weaving, papermaking, medicine, fermentation, casting, gluing, chemical industry, machinery and drilling well widely.But in the starch course of processing, can produce the acid organic waste water of a large amount of high densitys; Contain glucide, protein and organic acids etc. such as a large amount of remaining starch, glucose, fructose, SANMALT-S in the organic waste water; It is smelly to be prone to corruption, and chemical oxygen demand COD content is everlasting between 1000~30000mg/L; In addition, total nitrogen and phosphate concn are high in the starch wastewater, are to pollute one of the most serious waste water in the foodstuffs industry.
At present, China produces more than 300 ten thousand tons of starch per year, and according to existing complete processing, 1 ton of starch of average every production produces 10~20m
3Waste water, the nontoxicity of starch wastewater own, its pollutent mainly is the organism that glucide, protein, fat etc. generate naturally; Be prone to corrupt fermentation, make the water quality blackout smelly, enter the dissolved oxygen in the rivers meeting consume water; Promote the breeding of algae and waterplant, when the starch wastewater amount is big, river meeting severe depletion of oxygen; The generation anaerobism is corrupt, distributes stench, makes therefore death by suffocation of hydrocoles such as its fish, shrimp, shellfish.Therefore, starch wastewater is treated as the severe problem of ten minutes that present China starch production producer faces.
At present, the existing method of handling to starch wastewater both at home and abroad mainly contains physico-chemical process and biological process.
1, physico-chemical process: mainly comprise flocculent precipitation and the combined technical method of forming by flocculation and absorption.Though the physico-chemical process investment is little, working cost is high, and water outlet is difficult to reach emission standard.
2, biological process: mainly comprise aerobe method, anaerobic biological process and photosynthetic bacterium method etc., bioremediation is because have advantages such as cost is low, energy consumption is little, surplus sludge volume is few, thereby obtained the attention of environmental engineering circle.
Aspect the processing starch wastewater, main prior art is following:
1999; The China relevant technologies personnel of agricultural machinery research institute food machinery institute have proposed to brief talk middle-size and small-size yam starch factory WWT scheme; This article brief account the present situation of China's starch industry; Set forth present technology level and the discharge of wastewater situation of potato starch factory, proposed employing anaerobic-aerobic biochemical processing method, introduced producing technical scheme and the technical process that 5000 tons of yam starch factory discharge of wastewater carry out WWT per year.This starch wastewater treatment process technology is outmoded, and the waste water after the processing may cause secondary pollution; And still contain the lot of valuable resource in the waste water after handling, the discharging of waste water has caused the waste of precious resources.
In addition; In the existing wastewater processing technology corn starch wastewater is used to feed pigs through the throw out of barrier post precipitation, feeds chicken etc., waste water entered oxidation pond spontaneous fermentation 1~2 day, entered the Herba Eichhorniae pond then and purified 7 days; Enter the fine duckweed pond again and purify 7 days; Reach agricultural irrigation water quality standard, this part water is used to irrigate rice field, fruit tree and vegetables etc., realizes the utilization again of resource through this process.This treatment process is with low content of technology, in the waste water still some resource be wasted.
Summary of the invention
The technical problem that the present invention will solve provides a kind of biochemical processing method of middle-size and small-size wastewater of starch factory.Can effectively handle a large amount of starch wastewaters through the inventive method, its resource is farthest utilized, thereby obtain remarkable economic efficiency and environmental benefit.
In order to address the above problem, the technical scheme that the present invention adopts is:
The present invention provides a kind of biochemical processing method of middle-size and small-size wastewater of starch factory, and said biochemical processing method may further comprise the steps:
A, at first in starch wastewater, add the organic polymer coargulator polyacrylamide solution and the inorganic flocculating agent Poly aluminum Chloride (PAC) aqueous solution, mix then, obtain mixed solution, be formed with stable floc sedimentation in the mixed solution; The add-on of said polyacrylamide solution accounts for 2~4% of starch wastewater gross weight, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 1~2% of starch wastewater gross weight;
B, the mixed solution importing air flotation pool that step a is mixed carry out dissolved air flotation; Through after the dissolved air flotation; Isolate the suspended substance floc sedimentation that floats in the mixed solution, obtaining water outlet is protein liquid, and will passing through air flotation pool, to separate the water outlet obtain be that protein liquid adopts plate-and-frame filter press to carry out filter-press dehydration; Obtain starch albumen and filtered liq after the dehydration, gained starch albumen is processed protein fodder through the pipe bundle drier drying;
C, the filtered liq that obtains behind the step b filter-press dehydration imported in the IC anaerobic reactor carry out biochemical treatment; The filtered liq that is about to obtain is got into first reaction zone of reactor drum by the bottom of IC anaerobic reactor; The filtered liq that imports is diluted in water inlet through reactor drum; Organism in its filtered liq is fully reacted be degraded, produce a large amount of biogas simultaneously, the biogas part of generation is collected by the triphase separator of IC anaerobic reactor lower floor; A part of in addition biogas carries that mud gets into second reaction zone in filtered liq and the filtered liq secretly; Filtered liq gets in the gas-liquid separator that is provided with in second reaction zone under the effect of carrying secretly of biogas; Through gas-liquid separation; Biogas breaks away from filtered liq and effluxes collection, and residue filtered liq and mud get into the bottom of first reaction zone through return line under action of gravity;
D, step c is handled filtered liq that the back gets into first reaction zone bottom and mud through the IC anaerobic reactor import in the MBR membrane bioreactor and separate; The time that in the MBR membrane bioreactor, stops is 4~6h, and the content of control dissolved oxygen DO composition is 2~4 mg/L in the sepn process; Carry out drying through the mud that obtains after the separation of MBR membrane bioreactor and utilize again, the following clear liquid that obtains after the separation is discharging or recycle directly.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, the mass percentage concentration of polyacrylamide solution described in the step a is 0.05~0.1%; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 5~10%.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, described in the step b with gained starch albumen when the pipe bundle drier drying is processed protein fodder, drying conditions is that normal pressure, drying temperature are that 40~50 ℃, time of drying are 4~6h.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, isolate the suspended substance floc sedimentation that floats in the mixed solution described in the step b, isolate ss suspended solid and chemical oxygen demand COD in the starch wastewater behind the suspended substance
CrThe clearance of the two reaches respectively>=and 80% and>=30%.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, it is the tower reactor of 4~8:1 that the anaerobic reactor of IC described in the step c adopts aspect ratio; Said IC anaerobic reactor is operation under normal temperature condition, and volumetric loading is 17.0~22.0 kg COD
Cr/ (m
3D), settling region surface load 0.6 m
3/ (m
2H), reaction zone hydraulic detention time 5~7 h.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, what the membrane bioreactor of MBR described in the steps d adopted is polypropylene hollow fiber membrane, and the aperture of film is 0.1~0.45 μ m.
According to the biochemical processing method of above-mentioned middle-size and small-size wastewater of starch factory, steps d is through ss suspended solid and biochemical oxygen demand BOD in the clear liquid under the gained of MBR membrane bioreactor separation back
5Clearance reach respectively>=90% and>=85%.
Positive beneficial effect of the present invention:
1, at first in starch wastewater, adds organic floculant and inorganic flocculating agent in the treatment process of the present invention; Add inorganic flocculating agent and can produce electrical neutralizing effect; Wadding grain in the waste water is easy near being condensed into bigger wadding grain; The adding organic floculant can make between the wadding grain and form more stable big floc sedimentation through the adsorption bridging effect, helps dissolved air flotation like this, thereby can effectively isolate ss suspended solid and chemical oxygen demand COD in the waste water
CrThe present invention unites use organic floculant and inorganic flocculating agent, and not only flocculating effect is good, and can reduce the consumption of flocculation agent greatly.
The waste water that 2, will add flocculation agent in the treatment process of the present invention mixes; Utilize air flotation pool to separate; Filter dehydration is carried out in water outlet through obtaining after the dissolved air flotation, can obtain protein fodder after the filtration, ss suspended solid and chemical oxygen demand COD in the filtrate filtered
CrClearance reach respectively more than 80% with more than 30%.According to measuring and calculating, can extract protein fodder 5kg at this stage every cubic metre of waste water, according to 1150 yuan of/ton calculating, every cubic metre of waste water can bring benefits 5.75 yuan; Can extract protein fodder 5kg according to every cubic metre of waste water and calculate, can extract 3969 tons of protein fodders every year.The present invention carries out in the IC anaerobic reactor in the biochemical treatment process, and every cubic metre of waste water can reclaim 1.90m
3Biogas.Therefore,, not only effectively handled a large amount of starch wastewaters, also obtained extra economic benefit simultaneously through the present invention.Therefore, the present invention has remarkable economic efficiency and social benefit.
3, after starch wastewater is handled through the inventive method, the ss suspended solid in the starch wastewater, chemical oxygen demand COD
CrWith biochemical oxygen demand BOD
5Reduce to 86 mg/L, 127 mg/L and 22.5 mg/L respectively by original content 6862mg/L, 14467 mg/L and 8672 mg/L; Water outlet through obtaining after the last MBR membrane bioreactor separation promptly descends clear liquid can reach integrated wastewater discharge standard (GB8978-1996, first discharge standard) fully.Therefore,, not only efficiently solve the starch wastewater pollution problems, and in wastewater treatment process, also extracted protein fodder and obtained biogas, the extra economic benefit that obtained through treatment process of the present invention.So no matter the present invention aspect economic benefit or aspect social environment benefit, has significant effect.
4, after the present invention passes through to add flocculation agent, dissolved air flotation, the processing of IC anaerobic biological and MBR Membrane Bioreactor for Wastewater Treatment with starch wastewater; Can make the final effluent quality of starch wastewater of high density be superior to the GB8978-1996 first discharge standard; Final water outlet can be back to factory's wash-down water, flushing supply, greening water, landscape water; Not only reach the purpose of protection environment, practiced thrift conventional water resources simultaneously, obtained good ecological benefits; And reduced fresh water, reduced the enterprise water use cost.Thereby the present invention has remarkable economic efficiency.
Four, embodiment:
Following examples have been merely and have further specified the present invention, do not limit content of the present invention.
Embodiment 1:
The biochemical processing method of a kind of middle-size and small-size wastewater of starch factory of the present invention, the detailed step of said biochemical processing method is following:
A, at first in starch wastewater, add the organic polymer coargulator polyacrylamide solution and the inorganic flocculating agent Poly aluminum Chloride (PAC) aqueous solution, mix then, obtain mixed solution, be formed with stable floc sedimentation in the mixed solution; The mass percentage concentration of said polyacrylamide solution is 0.08%, and the add-on of polyacrylamide solution accounts for 3% of starch wastewater gross weight; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 8%, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 1.5% of starch wastewater gross weight;
B, the mixed solution that step a is mixed import air flotation pool and carry out dissolved air flotation, through after the dissolved air flotation, isolate the suspended substance floc sedimentation that floats in the mixed solution and (isolate ss suspended solid and chemical oxygen demand COD in the starch wastewater behind the suspended substance
CrThe clearance of the two reaches respectively>=and 80% and>=30%), obtaining water outlet is protein liquid; To pass through air flotation pool, to separate the water outlet obtain be that protein liquid adopts plate-and-frame filter press to carry out filter-press dehydration, obtains starch albumen and filtered liq after the dehydration, and gained starch albumen is processed protein fodder through the pipe bundle drier drying; Drying conditions is that normal pressure, drying temperature are that 40 ℃, time of drying are 6h when pipe bundle drier is dry;
C, the filtered liq that obtains behind the step b filter-press dehydration imported in the IC anaerobic reactor carry out biochemical treatment; The filtered liq that is about to obtain is got into first reaction zone of reactor drum by the bottom of IC anaerobic reactor; The filtered liq that imports is diluted in water inlet through reactor drum; Organism in its filtered liq is fully reacted be degraded, produce a large amount of biogas simultaneously, the biogas part of generation is collected by the triphase separator of IC anaerobic reactor lower floor; A part of in addition biogas carries that mud gets into second reaction zone in filtered liq and the filtered liq secretly; Filtered liq gets in the gas-liquid separator that is provided with in second reaction zone under the effect of carrying secretly of biogas; Through gas-liquid separation; Biogas breaks away from filtered liq and effluxes collection, and residue filtered liq and mud get into the bottom of first reaction zone through return line under action of gravity;
It is the tower reactor of 4~8:1 that said IC anaerobic reactor adopts aspect ratio; Said IC anaerobic reactor is operation under normal temperature condition, and volumetric loading is 17.0~22.0 kg COD
Cr/ (m
3D), settling region surface load 0.6 m
3/ (m
2H), reaction zone hydraulic detention time 5~7 h;
D, step c is handled filtered liq that the back gets into first reaction zone bottom and mud through the IC anaerobic reactor import in the MBR membrane bioreactor and separate that (what said MBR membrane bioreactor adopted is polypropylene hollow fiber membrane; The aperture of film is 0.1~0.45 μ m); The time that in the MBR membrane bioreactor, stops is 4~6h, and the content of control dissolved oxygen DO composition is 2~4 mg/L in the sepn process; Carry out drying through the mud that obtains after the separation of MBR membrane bioreactor and utilize again, the following clear liquid that obtains after the separation is discharging or recycle directly; Through ss suspended solid and biochemical oxygen demand BOD in the clear liquid under the gained of MBR membrane bioreactor separation back
5Clearance reach respectively>=90% and>=85%.
Embodiment 2: basic identical with embodiment 1, difference is:
Among the step a: the mass percentage concentration of said polyacrylamide solution is 0.05%, and the add-on of polyacrylamide solution accounts for 4% of starch wastewater gross weight; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 10%, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 1.0% of starch wastewater gross weight;
Among the step b: drying conditions is that normal pressure, drying temperature are that 50 ℃, time of drying are 4h when pipe bundle drier is dry.
Embodiment 3: basic identical with embodiment 1, difference is:
Among the step a: the mass percentage concentration of said polyacrylamide solution is 0.1%, and the add-on of polyacrylamide solution accounts for 2% of starch wastewater gross weight; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 5%, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 2% of starch wastewater gross weight;
Among the step b: drying conditions is that normal pressure, drying temperature are that 45 ℃, time of drying are 5h when pipe bundle drier is dry.
Embodiment 4: basic identical with embodiment 1, difference is:
Among the step a: the mass percentage concentration of said polyacrylamide solution is 0.065%, and the add-on of polyacrylamide solution accounts for 3.5% of starch wastewater gross weight; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 9%, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 1.2% of starch wastewater gross weight.
Embodiment 5: basic identical with embodiment 1, difference is:
Among the step a: the mass percentage concentration of said polyacrylamide solution is 0.09%, and the add-on of polyacrylamide solution accounts for 2.5% of starch wastewater gross weight; The mass percentage concentration of the said Poly aluminum Chloride (PAC) aqueous solution is 6%, and the add-on of the Poly aluminum Chloride (PAC) aqueous solution accounts for 1.8% of starch wastewater gross weight.