CN1027984C - Recovery and reuse method of papermaking effuent - Google Patents

Abstract

The present invention relates to a method for processing the mixed waste water of black liquid, mid-section water and white water produced in the process of paper making. According to the method, first of all, calcium carbide plaster or lime is added to waste water, and then, the coagulants of halogen blocks, halogen water, sea water or the like are used for processing the waste water; air and flue gas are led into obtained supernatant fluid 1; after the separation of solid and liquid, obtained supernatant fluid 2 is processed by carboxymethyl cellulose sodium and aluminum sulfate; and finally, obtained supernatant fluid 3 passes through an activated carbon adsorption bed. Water processed by the method can be drained or reused. The method has the advantages of simple technology, convenient operation, lower cost and high pollutant removal rate.

Description

Recovery and reuse method of papermaking effuent

The invention belongs to method of wastewater treatment.

Here said waste water is meant the paper waste of being made up of black liquor, middle section water and plain boiled water, also comprises the waste water that forms when making recycled writing paper.Mainly contain in the paper waste bark, careless bits, silt, ashes, slag,, solids such as filler, lignin, paper pulp staple fibre, dissolved organic matters such as the sulfide of trace, volatile phenol, organic chloride, and alkali (or acid or salt, look the difference of production method and different) etc., the degree of polluting is mainly represented by the content of pH, CODcr, SS and micro-phenol and sulfide, concerning large-scale paper mill, it is successful abroad burning black liquor with incinerator and carrying out the method that alkali reclaims.Remaining middle section water and plain boiled water then are easy to handle, and its method is a lot.The paper-making industry of China accounts for 57% by the medium and small enterprise of its production capacity, it is non-remunerative economically that this small business adopts above-mentioned burning method, and black liquor is being carried out do not find suitable method so far as yet aspect the alkali recovery, because industrially-advanced country does not have small-sized paper mill, thereby the wastewater processing technology in small-sized paper mill is not used for reference yet.Domestic biological treatment, materialization treatment process and the comprehensive use studied, these methods are all implemented respectively to handle to a certain in the paper waste or certain two kinds of waste water.The present invention handles the composite waste of being made up of black liquor, middle section water and plain boiled water together, rather than handles respectively, and water after treatment can be back to original production again.

The invention belongs to physico-chemical process, no matter the paper waste that is formed by which kind of papermaking process all adds calcium carbide mud or lime earlier, they help heavy effect to pollutant in the waste water, and can utilize its alkalescence to make the pH value rising of waste water.And then the adding flocculating agent, for example enriched bittern cake or bittern or seawater, they all contain by Mg ²⁺, Na ⁺, K ⁺, Ca ²⁺, Sc ³⁺, TiO ²⁺, Cr ³⁺, Cu ²⁺, Zn ²⁺, Al ³⁺Deng sulfate, chloride, carbonate, phosphate, the borate formed.After these materials and alkaline waste water are had an effect, there is hydroxide to generate, the latter has cohesion, flocculation, suction-operated to pollutant in the waste water, between charged complex ion or ionic group and the pollutant strong cohesion is arranged also in this external flocculating agent and the waste water mixed system, newly-generated wadding piece also has strong suction-operated, thereby effectively pollutants in waste water is removed in cohesion-adsorption process.This novel flocculating agent is not only to the CODcr in the waste water, BOD ₅, colourity clearance higher, and settling velocity is also very fast.In 20 liters container, can finish sedimentation substantially in 5～10 minutes.

Composite waste process method step of the present invention is as follows:

1. earlier under agitation add dried calcium carbide mud or lime to a certain amount of waste water, make the pH of waste water be increased to 10.24～13.40, the consumption of dried calcium carbide mud is every liter of waste water 0.5～0.7 gram, and lime consumption is 0.3～0.6 gram; Continuing to add flocculating agent enriched bittern cake or bittern or seawater under the stirring then, the enriched bittern cake consumption is every liter of waste water 0.3～0.5 gram, and the bittern consumption is 0.3～0.7 milliliter of every liter of waste water, and the consumption of seawater is 1: a 0.5～1(volume ratio).After adding flocculating agent, waste water is entered a heavy pond, enter the precipitation that produces in the waste water behind the heavy pond and promptly begin sedimentation, the mud that comes that avales enters sludge dewatering equipment by mud discharging mouth, and the mud of making is done to mix in the coal and directly burnt, and also can be made into moulded coal.The water of being discharged by a heavy pond is that supernatant 1 has been removed most of pollutant, mostly is light yellow, no suspended substance.

2. make above-mentioned supernatant 1 constantly flow into aerating system, carry out jet-flow aeration, in waste water, introduce air and the flue gas after smoke abatement and dust control during aeration, and the decontamination factor of control water is between 5～50%.Like this, after this waste water enters second pond, promptly produce carbonate deposition, the water after the Separation of Solid and Liquid is supernatant 2, and its CODcr, BOD and colourity etc. further reduce.

3. add sodium cellulose glycolate (CMC) and Al to the above-mentioned supernatant of telling 2 ₂(SO ₄) ₃, the consumption of the two is: the former concentration in waste water is 1～2ppm, and the latter is 3～5ppm, and pollutant levels reduce once more in the waste water of this processing, and the sediment that avales in three heavy ponds gets supernatant 3 after the Separation of Solid and Liquid.

4. make above-mentioned supernatant 3 enter clear water reserviors by activated carbon adsorption bed.

Through the water that above-mentioned four steps handle, its pH is 7.0 ± 0.5, CODcr＜200mg/l, BOD ₅＜60mg/l, colourity≤20 degree (K ₂PtCl ₆Colorimetric method), sulfide＜1mg/l, volatile phenol＜0.5mg/l, the water in the visible clear water reserviors has reached standard, and it both can blowback produce upward use, can also discharge.

By the mud of discharging in second pond and the three heavy ponds, its processing method is identical with a heavy pond.

The present invention's technology aspect practical application is simple, easy to operate, and medicament expense is lower, and pollutants removal rate is higher.Wherein the clearance to colourity all is higher than 99%, and between 93.9～98.4%, the total hardness of water all is lower than 10 German degree to the clearance of CODcr, and the reclamation rate of water can be higher than 80%(by discharge capacity).

The present invention is applicable to that with timber, bamboo reed, straw, straw etc. be the paper mill of raw material, also is applicable to regeneration paper plant, and under latter event, treatment process can also be simplified.Handle with all available method of the present invention of waste water that the whole bag of tricks such as acid system, alkaline process, inferior sodium method, lime method, the papermaking of ground wood method are produced.In brief, except that Ammonium Sulfite Method, no matter the scale of factory, all can be suitable for, but since large-scale paper mill do alkali reclaim more favourable, so the present invention is mainly used in the wastewater treatment in medium and small paper mill, especially in water resource day by day under the situation of shortage, social benefit of the present invention, the more significant of environmental benefit and economic benefit.

Embodiment 1:

The raw material straw of certain paper mill papermaking accounts for 70%, and timber accounts for 30%, day 2000 tons of composite wastes of row, pH7.84～9.0, brownish black, colourity 3700～5000 colourities doubly, CODcr2983～3165mg/l is about sulfide 10mg/l, about volatile phenol 10mg/l.Get 18 liters in this water, add dried calcium carbide mud 9 grams and add flocculating agent 7.2 grams under constantly stirring, Separation of Solid and Liquid is carried out in natural sedimentation after 9 minutes, get supernatant 1.The pH of this supernatant 1 is 12.44, colourity be 350 colourities doubly, clearance is 90.5%; CODcr is 630mg/l, and clearance is 80.1%; Sulfide is 0.8mg/l, and clearance is 92%, and volatile phenol is 0.4mg/l, and clearance is 96%, and blowing air and flue gas jet-flow aeration in this supernatant 1 make decontamination factor reach at 37% o'clock and then produce white precipitate, carry out Separation of Solid and Liquid subsequently and get supernatant 2.The pH of this supernatant 2 is 9.61, colourity be 130 colourities doubly, the accumulation clearance is 96%, CODcr is 417.mg/l, the accumulation clearance is 86.8%, stirs to add CMC1ppm, Al down again in supernatant 2 ₂(SO ₄) ₃4ppm then produces faint yellow precipitation, gets supernatant 3 after the Separation of Solid and Liquid.The pH of this supernatant 3 is 6.80, colourity be 35 colourities doubly.The accumulation clearance is 99.1%; CODcr is 124mg/l, and the accumulation clearance is 96.1%.PH with water its water outlet after charcoal absorption is 6.78 then, colourity be 2 colourities doubly, total clearance is 99.9%, CODcr is 78mg/l, total clearance is 97.9%, BCD ₅Be 42mg/l, sulfide is 0.3mg/l, total clearance 97%, and volatile phenol is 0.2mg/l, total clearance 98%.

Embodiment 2

Certain paper mill is with straw, straw is a paper making raw material, 1400 tons of day row's composite wastes, pH6.84～6.96, color of soy sauce, colourity 4000～8000 colourities doubly, CODcr is between 3000～3259mg/l, about sulfide 8mg/l, volatile phenol 4mg/l, get 3 liters in this water, add each 1.2 gram of lime (making emulsion) and flocculating agent under stirring, natural subsidence is carried out Separation of Solid and Liquid after 8 minutes, get supernatant 1, the pH of this supernatant 1 is 12.03, colourity 320 colourities doubly, clearance is 92%, CODcr is 580mg/l, clearance is 80.7%, and sulfide is 0.6mg/l, and clearance is 92.5%, volatile phenol is 0.3mg/l, clearance is 92.5%, and the gas that smoke uptake gas mixes with air in this supernatant 1 carries out jet-flow aeration, makes decontamination factor reach at 33% o'clock and then produces white precipitate, after Separation of Solid and Liquid, get supernatant 2, the pH of this supernatant 2 is 9.77, colourity 128 colourities doubly, the accumulation clearance is 96.8%, CODcr is 421mg/l, and the accumulation clearance is 85.9%.Under agitation in this supernatant 2, add CMC1.1ppm, ASl then ₂(SO ₄) ₃4.2ppm, produce the yellow-white precipitation, get supernatant 3 after the Separation of Solid and Liquid, the pH of this supernatant 3 is 6.91, colourity be 30 colourities doubly, the accumulation clearance is 99.3%, CODcr is 131mg/l, and the accumulation clearance is 95.6%, and supernatant 3 obtains final outflow water after active-carbon bed absorption, the pH of this final outflow water is 7.02, about 2 colourities of colourity doubly, total clearance is 99.9%, CODcr is 56.9mg/l, total clearance is 98.1%, BOD ₅Be 40mg/l, sulfide is 0.3mg/l, total clearance 96%, volatile phenol 0.2mg/l, total clearance 95%.

Embodiment 3

The raw material timber in certain paper mill accounts for 60%, and straw accounts for 40%, day 5000 tons of composite wastes of row, pH6.0～11.7, brownish black, colourity 3000～4500 colourities doubly, CODcr1130～3570(average 2639) between the mg/l, sulfide 8mg/l, volatile phenol 2mg/l.Get 12 liters in this water, add calcium carbide mud 8.4 grams and flocculating agent 6 grams under stirring, the post precipitation Separation of Solid and Liquid gets supernatant 1, the pH of this supernatant 1 is 12.37, colourity 300 colourities doubly, clearance is 90%, CODcr is 504mg/l, clearance is 80.9%, sulfide is 0.4mg/l, and clearance 95%, volatile phenol are 0.2mg/l, clearance 90%, smoke uptake gas and Air mixing gas carry out jet-flow aeration in supernatant 1, make decontamination factor reach at 34.3% o'clock and produce white precipitate, the supernatant 2 after the Separation of Solid and Liquid, the pH of this supernatant is 9.12, colourity 220 colourities are doubly accumulated clearance 92.6%, and CODcr is 414mg/l, accumulation clearance 84.3% adds 1ppmCMC and 4ppmAl under stirring again in supernatant 2 ₂(SO ₄) ₃, producing faint yellow precipitation, the pH of the supernatant 3 that obtains after the Separation of Solid and Liquid is 7.03, colourity 25 colourities doubly, the accumulation clearance is 99%, CODcr is 119mg/l, accumulation clearance 95%, supernatant 3 obtains final outflow water again after active-carbon bed absorption, and the pH of this water is 7.03, colourity 2 colourities doubly, total clearance is 99.9%, CODcr is 69mg/l, total clearance 97%, BOD is 42mg/l, sulfide is 0.2mg/l, total clearance 97.5%, volatile phenol 0.1mg/l, total clearance 95%.

Claims (1)

1, a kind of method of handling the black liquor, middle section water and the plain boiled water composite waste that produce in the paper-making process, it is characterized in that in composite waste, adding earlier dried calcium carbide mud or lime, again with enriched bittern cake or bittern agglomeration process, after telling mud, bubbling air and flue gas mist in gained supernatant 1, after telling mud once more, get supernatant 2, this supernatant is handled with sodium cellulose glycolate and aluminum sulfate, after telling mud for the third time, with gained supernatant 3 usefulness slags or anthracite or tail over charcoal absorption and handle.

The consumption of described dried calcium carbide mud is every liter of waste water 0.5-0.7 gram, and the consumption of lime is the 0.3-0.6 grams per liter, and the pH that should make waste water is between 10.24-13.40; Described enriched bittern cake consumption is the 0.3-0.5 grams per liter, bittern be the 3-7 milliliter/liter; The used in amounts of described sodium cellulose glycolate and aluminum sulfate makes its concentration in waste water be respectively 1-2ppm and 3-5ppm.