A kind of double-layer compound biological filter material for aerated biological filter and preparation method thereof
Technical field
The present invention relates to filtrate and preparation method, be specifically related to a kind of double-layer compound biological filter material for aerated biological filter and preparation method thereof.
Background technology
As everyone knows, in biomembrance process, BAF is one of visual plant, (Biological Aerated Filter BAF) has that technology is simple, processing efficiency is high, floor space is little, organic volumetric loading is big, the residence time is short, integrates bio-oxidation and holds back suspended solids, saves second pond, less investment, low, the effluent quality advantages of higher of energy consumption BAF; In use, filtrate forms microbial film in the filter tank, and microbial film is made up of bacterium, fungi, algae, protozoon, metazoan etc.; When effluent stream during through filter bed, some pollutent and bacterial adhesion are on filter material surface, and microorganism just breeds in a large number at filter material surface, forms one deck microbial film, and its thickness is about 2mm; Organic pollutant in the sewage is degraded through the microorganism aerobic metabolism, and product is CO
2, H
2O, NH
3Deng; The microorganism of microbial film internal layer then carries out anaerobic metabolism, and product is organic acid, ethanol and H
2S etc.; Because the continuous breeding of microorganism, the microbial film progressive additive is when surpassing certain thickness, the internal layer microorganism enters endogenous metabolism because of can not get sufficient nutriment, lose it and stick to performance on the filtrate, split away off with water and flow out the filter tank, filter material surface grows new microbial film more again; The physical and chemical performance of filter material surface affects microbial growth, breeds, comes off and form; Filtrate itself can also adsorb and hold back the suspended substance in the sewage, stops bubble, and it is long-pending to increase gentle, liquid surface in contact of its residence time in water, reduces aeration rate, thus save energy, and reduce equipment volume; Therefore, the research and development of high-performance biofilter material is the key of BAF technology.
At present, biofilter material is mainly organic polymer filtrate and inorganic filtrate; The organic polymer filtrate has polystyrene, polyvinyl chloride, polypropylene etc., and the consistency between they and microorganism is relatively poor, and biomass is few during biofilm, easily comes off, and treatment effect is not so good, and costs an arm and a leg, and uses few in BAF technology; Inorganic filtrate mainly contains quartz sand, volcanics, gac, hard coal, zeolite etc.; Quartz sand now substantially uses separately owing to there are shortcomings such as density is big, specific surface area is little, porosity is low, the filter tank cycle of operation short, head loss increases comparatively fast, wash-down water consumption is big; Gac and volcanics price are expensive; Hard coal, zeolite pore are less relatively, easily stop up, and the back flushing resistance is bigger.
Because the existing various defectives of lithotroph filtrate, the filtrate expert has carried out a large amount of study on the modification to it both at home and abroad, mainly is divided into filter material surface modification and composite modified research; Can make after the surface modification that the little filtrate micropore of porosity increases, specific surface area becomes big, the active centre of having enriched solid surface has strengthened it and has removed the performance of foreign ion in water, and filter effect is improved, effluent quality obviously improves; Composite filtering material mainly is all kinds of ceramic grain filters, and its wide material sources can be at different quality; The lithotroph filtrate of various modifications becomes the main body of BAF filtrate gradually.
On September 28th, 2005 Granted publication CN1220543C patent " a kind of bioactive filter material and roasting technology thereof that is used for water treatment ", the employing clay is a main raw material, with xylogen and sulfonate as fluidizer, polyvinyl alcohol is as preparation filtrates such as whipping agents, but in the actual use, COD and ammonia nitrogen removal frank are not high, are to the maximum about 70%.
On December 27th, 2006 Granted publication CN1291926C patent " a kind of manufacture method that is used for wastewater treatment ball-type ature of coal micropore biofilter material ", adopt coal and binding agent after balling-up in 100~600 ℃ of shapings; On October 8th, 2008 Granted publication CN100423808C patent " production method of concave convex stick ceramic grain filter ", adopt attapulgite clay, coal gangue, volcanic ash at 350~500 ℃ of thermal sinterings; More than two patents since the thermal sintering temperature low, do not reach the potteryization temperature, sour corrosion rate and alkali corrosion rate are higher, intensity and wear resistance are relatively poor, can be used for the sorbent material of purification of water quality, but be not suitable as the filtrate use of BAF, because not anti-back flushing.
On December 19th, 2007 Granted publication CN100355671C patent " a kind of novel filtrate that is applied in the biological aerated filter technology ", adopt preparation filtrates such as flyash, cement, sepiolite, owing to be to prepare gained by cement ageing maintenance, intensity and porosity are not as the ceramic grain filter of high temperature sintering.
On July 23rd, 2008 Granted publication CN101224359A patent " but preparation method of suspended compound clay filtering material ", adopt the recessed soil of polyethylene foamed surface coverage, the sample of preparation can suspend, relatively being fit to fish culture waste water handles, since bigger from suspension rolling collision friction in water, not too be fit to the BAF biofilm.
On September 10th, 2008 Granted publication CN100417605C patent " highly effective filtering material for biology and preparation method thereof ", adopting laterite and flyash to pulverize 1050~1250 ℃ of agglomerating backs of sintering makes, because the laterite porosity is less, the filtrate specific surface of preparation is also less, and irregular filtrate has increased flow resistance, the backwashing pressure of needs raising BAF.
On October 29th, 2008 Granted publication CN101293768A patent " a kind of biofilter material and preparation method thereof "; adopt clay, flyash, pore-forming material etc. to be prepared from; pore-forming material is that price is relatively costly, very active, the dangerous high calcium carbide of chemical property, has promoted the preparation cost of filtrate.
On January 21st, 2009 Granted publication CN100453503C patent " Biohaydite filter material and preparation method thereof ", adopting flyash, mud, Walocel MT 20.000PV is the adhesive preparation filtrate, and be coated with the iron modification by the surface, improve ammonia nitrogen Static Adsorption ability, but little to the bio-film colonization effect.
Summary of the invention
The objective of the invention is to: provide a kind of double-layer compound biological filter material for aerated biological filter and preparation method thereof, the two-layer compound biofilter material surface irregularity that adopts this preparation method to obtain, voidage height, wear resistance is good, intensity is big, and easy to be filmed is economical and practical.
Technical solution of the present invention is: this two-layer compound biofilter material is composited by ectonexine; Internal layer is made up of recessed soil and flyash, and its weight ratio is 4: 6; Skin is made up of recessed soil, diatomite and coal dust, and its weight ratio is 7-10: 9-12: 1.
The preparation method of two-layer compound biofilter material of the present invention is: at first, recessed soil and flyash are worn into 100 purpose powder respectively, and 100 order powder of recessed soil and flyash mixed by weight 4: 6, were the solid globule core of particle diameter 5~6mm at the tablets press internal shaping; Secondly, recessed soil, diatomite, coal dust are worn into 100 purpose powder respectively, 100 order powder of recessed soil, diatomite, coal dust are 7-10: 9-12 by weight: 1 mixes, powder mix slowly adds in the tablets press continuously, continuation coats granulation on solid globule core surface, and obtaining diameter is the finished product bead of 7~8mm; At last, the finished product bead dried 24 hours naturally, and 120 ℃ of dry 2h take out in the constant temperature air dry oven, directly are put into 950 ℃~1050 ℃ sintering 20min in the chamber type electric resistance furnace, and naturally cooling gets the two-layer compound biofilter material.
The present invention has the following advantages: 1, verified the two-layer compound biofilter material by a large amount of dynamic experiments, outer field component films performance is good, and the component of internal layer is relatively inexpensive, and integral body has moderate porosity, kernel intensity height;
2, attapulgite clay (being called for short recessed soil) is a kind of silicate of rich magnesium, and crystalline structure belongs to 2:1 type layer chain clay mineral, and structure that it is special and character have been given very high use value; It has bigger specific surface area on the one hand, can be used as good filtrate component; Recessed on the other hand soil self has good stickiness, is convenient to filtrate and is shaped, and need not add other binding agent again; Attapulgite mineral various places almost all over the world, many attapulgites ore deposit point is verified on ground such as China Jiangsu, Anhui, Shandong, Liaoning, output ranks first with the area, Xuyi in Huaian, Jiangsu, its reserves have now been verified up to 2.72 hundred million tons, prospective reserves reaches 500,000,000 tons, account for 70% of Chinese attapulgite reserves, account for the nearly 50% of global attapulgite total reserves, be world's high-quality mineral reserve;
3, diatom is a kind of microbody siliceous organism of living in sea or the lake basin ground, genus polyporus shell unicellular algae, individual diameter is only differentiated at microscopically, diatom experience natural propagation process is dead to the end, the organic disappearance, bone sinks under water and can form the diatom accumulation, under suitable sedimentary environment and geologic condition, be piled into the diatomite mineral deposit, at present in Jilin, Yunnan, 14 provinces such as Zhejiang, autonomous region has found diatomite ore, in the mineral deposit of having found, with the Changbai mountain, Jilin area, Shengzhou, Zhejiang city is largest, reserves are maximum, reserves are all more than hundred million tons, occupy prostatitis, the world, because diatomite has unique microvoid structure, the porosity height, in light weight, therefore physical propertiess such as strong adsorptivity are widely used among the industrial and agricultural production, just because of itself being exactly to form after the microorganism silication, formed space is particularly suitable for microbial growth in the microbial film;
4, flyash is a kind of solid waste of discharging in the coal-fired process, the a large amount of flyash of the annual discharging of coal-fired enterprise such as power station, as not dealing carefully with, will cause serious environmental to pollute, flyash is in forming process, and portion gas is not overflowed to be rolled in and formed the closure hole in the particle, though inside is cellular, absorption property is but very little, not as recessed soil and diatomite, but cheap and easy to get;
5, learn by a large amount of tests, the biofilter material of recessed soil and the compound preparation of diatomite is used for the BAF biofilm and disposes of sewage, over-all properties obviously is better than recessed soil and flyash compound biofilter material, the microbial film general thickness that the filtrate outside surface forms is 2mm, the filtrate solid object surface then is the place of microbial reproduction growth, mainly concentrate on the thick upper layer of the about 1mm of filtrate, because diatomite belongs to nonmetalliferous ore, price is far above the flyash of waste, therefore, biofilter material newly developed adopts bilayer structure, and inside is recessed soil and flyash complex body, outermost layer is recessed soil, the composite bed of diatomite and coal dust, with low cost;
6, expanding agent adopts coal dust, promptly forms by cleaned coal is levigate, and moderate cost, quality are easy to control;
7, the adding of expanding agent coal dust can form bigger duct, inside, helps microorganism growth on the filtrate, obtains moderate voidage and higher compressive strength, long service life;
8, the maturing temperature scope is 950 ℃~1050 ℃, reaches the potteryization temperature, and sour corrosion rate and alkali corrosion rate are lower, and particle surface part glazing can not occur, and internal capillary can fusion yet, and filtrate available ratio surface increases, and helps biofilm.
Embodiment
Describe technical solution of the present invention in detail below in conjunction with specific embodiment, these embodiment can not be interpreted as it is restriction to technical scheme.
Embodiment 1:
Recessed soil and flyash are worn into 100 purpose powder respectively, and 100 order powder of recessed soil and flyash mixed by weight 4: 6, were prepared as the solid globule core of particle diameter 5~6mm in tablets press; Recessed soil, diatomite, coal dust are worn into 100 purpose powder respectively, 100 order powder of recessed soil, diatomite, coal dust are to mix at 7: 12: 1 by weight, slowly add in the tablets press continuously, continue to coat granulation on solid globule core surface, obtaining diameter is the finished product bead of 7~8mm; Naturally dried 24 hours, 120 ℃ of dry 2h take out in the constant temperature air dry oven, directly are put into 1000 ℃ of sintering 20min in the chamber type electric resistance furnace, and naturally cooling is the two-layer compound biofilter material.
After the BAF biofilm, normal water inlet, measure entry COD and be about 380~390mg/L, NH3-N is about 9~12mg/L, hydraulic detention time is about 4 hours, the water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 85.3% in back again 5 days, and the NH3-N average removal rate is 93.2%.
Embodiment 2:
Recessed soil and flyash are worn into 100 purpose powder respectively, and 100 order powder of recessed soil and flyash mixed by weight 4: 6, were prepared as the solid globule core of particle diameter 5~6mm in tablets press; Recessed soil, diatomite, coal dust are worn into 100 purpose powder respectively, 100 order powder of recessed soil, diatomite, coal dust are to mix at 7: 12: 1 by weight, slowly add in the tablets press continuously, continue to coat granulation on solid globule core surface, obtaining diameter is the finished product bead of 7~8mm; Naturally dried 24 hours, 120 ℃ of dry 2h take out in the constant temperature air dry oven, directly are put into 950 ℃ of sintering 20min in the chamber type electric resistance furnace, and naturally cooling is the two-layer compound biofilter material.The water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 89.5% in back again 5 days, and the NH3-N average removal rate is 96.4%.
Embodiment 3:
Recessed soil and flyash are worn into 100 purpose powder respectively, and 100 order powder of recessed soil and flyash mixed by weight 4: 6, were prepared as the solid globule core of particle diameter 5~6mm in tablets press; Recessed soil, diatomite, coal dust are worn into 100 purpose powder respectively, 100 order powder of recessed soil, diatomite, coal dust are to mix at 7: 12: 1 by weight, slowly add in the tablets press continuously, continue to coat granulation on solid globule core surface, obtaining diameter is the finished product bead of 7~8mm; Naturally dried 24 hours, 120 ℃ of dry 2h take out in the constant temperature air dry oven, directly are put into 1050 ℃ of sintering 20min in the chamber type electric resistance furnace, and naturally cooling is the two-layer compound biofilter material.The water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 87.4% in back again 5 days, NH
3-N average removal rate is 94.6%.
Embodiment 4:
Except continue to add recessed soil, diatomite, coal dust solid globule core is 8.5: 10.5: 1 powder mix by weight, and granulation is the finished product bead of 7~8mm, and all the other conditions are constant with embodiment 1.The water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 81.5% in back again 5 days, NH
3-N average removal rate is 89.7%.
Embodiment 5:
Except continue to add recessed soil, diatomite, carbon dust weight ratio solid globule core is 8.5: 10.5: 1 powder, and granulation is the finished product bead of 7~8mm, and all the other conditions are constant with embodiment 2.The water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 84.3% in back again 5 days, NH
3-N average removal rate is 92.6%.
Embodiment 6:
Except continue to add recessed soil, diatomite, carbon dust weight ratio solid globule core is 10: 9: 1 powder, and granulation is the finished product bead of 7~8mm, and all the other conditions are constant with embodiment 3.The water treatment effect is basicly stable after 14 days, and water outlet COD average removal rate was 82.1% in back again 5 days, NH
3-N average removal rate is 91.3%.
The concrete numerical value of each composition that embodiments of the invention adopt only is to represent mutual proportionlity, it is not limited to the use of this numerical value in actual applications, can realize purpose of the present invention as long as meet mutual proportionlity, so all should be in protection scope of the present invention; Simultaneously; because the existence of permissible error is arranged in preparation process; the numerical value that the present invention mentioned also just has the meaning of directiveness, so as long as used the preparation and the modified condition of process of the present invention in actual applications, promptly should be in protection scope of the present invention.