CN1132184A

CN1132184A - Leather waste water treatment technique

Info

Publication number: CN1132184A
Application number: CN95111298A
Authority: CN
Inventors: 薛波; 薛长春
Original assignee: HUAXI ENVIRONMENTAL PROTECTION SCIENCE AND TECH Co CHENGDU CITY
Current assignee: HUAXI ENVIRONMENTAL PROTECTION SCIENCE AND TECH Co CHENGDU CITY
Priority date: 1995-03-31
Filing date: 1995-03-31
Publication date: 1996-10-02

Abstract

An improved process for treating waste water from tannery includes removing hair, down and big blocks of hide dust and fat by passing the waste liquid through lattice pond, anaerobic digestion in full-enclosed anaerobic regulation pool, oxidation in oxidizing ditch and coagulating deposition in coagulating-depositing pool that features that it is only thing to charge chemical in January, February and December. It is characterized by low cost of chemical, small total size and use of deposited matter as raw material of organic fertilizer.

Description

Leather waste water treatment technique

The invention belongs to leather waste water treatment process in the Industrial Wastewater Treatment

Trade effluent is one of the main source in contaminate environment waters.Leather waste water is a trade effluent.It derives from the production processes such as unhairing in the production process of all kinds of tanneries, tanning, process hides, dyeing, moulding.The important feature of waste water: wastewater discharge is big, pollutant kind is many, colourity, PH, CODcr value high, and this waste water is the composition complexity not only, and the variation of water quality, the water yield, water temperature and pH value etc. is big.Harmful poisonous things such as its pollutent such as SS, CODcr, BOD5, chromium, sulphur, grease are all above tens of times and even hundreds of times of state-set standard.

At present leather waste water is handled and is mainly contained the several methods such as processing that physico-chemical process, biochemical process, materialization-biochemistry combine.

In physico-chemical process is handled, the chemical coagulation and precipitations (or air supporting) that adopt are handled more, medicament expense (comprising coagulating agent, organic polymer coagulant aids etc.) accounts for about 80 percent of handling, treated leather waste water also is difficult to reach discharging standards, so this treatment process is difficult to apply.

Biochemical process adopts the aerobic treatment method more, because waste water composition complexity, and the pollution concentration height, so long processing period not only, investment is big and power consumption is high, floor space is big.Adopt single biochemical process treatment process, processed waste water is difficult to qualified discharge.

Materialization-biochemical processing process that adopt in leather waste water is handled at present more, as the 223rd to 224 page of the 6th of Nanjing tannery on October 8 nineteen ninety " leather making integrated waste water treatment project final acceptance of construction is reported " and " feedwater discharging design manual " that in September, 1986, China Construction Industry Press published upward 4.6.10 " tanning sewage " all be typical treatment process.

Leather making integrated sewage makes materials such as sulfur-bearing, oxidation under catalytic condition through dispensing air supporting.Enter the oxidation ditch aerobic treatment process again, wherein the width of oxidation ditch ratio is 2: 1, and aerator is submerged in the inversed umbrella type aeration in the waste water, and the net volume of oxidation ditch is the twice of wastewater treatment capacity, and oxidation ditch surface low speed is about 0.3 meter per second.Waste water outwards discharges after settling tank is up to standard after treatment.

Mud advances concentration basin, adds flocculation agent, through concentrating pressure filter moulding outward transport.

Though this treatment process has preferably the clearance can qualified discharge, medicament expense is with high, and the big maintenance cost height of equipment corrosion, expenditure on power are big, floor space brings one-time investment big greatly, and general medium and small tannery is difficult to carry out and bears.

The national conditions that the object of the invention is present according to China had both been handled leather water wasting qualified discharge well, protected water environment; reach reduced investment again, operating cost (medicament, power consumption etc.) is low, and treatment effect is reliable and stable; it is fertile that operation, maintenance and convenient management, mud can be used as farming, do not produce secondary pollution.Lack the area in water resources, waste water after treatment also can be back to tanning production.

The present invention improves on existing leather waste water treatment technique basis, and optimum combination forms again.Main technique is: will contain chromium, sulfur-bearing, contain a large amount of Sodium Sulphide, lime waste water gathers through recycling and post precipitation and be synthetic leather wastewater, through adjusting, anaerobism, air supporting, secondary filtration and jet-flow aeration second-stage treatment.Waste water after once filtering enters the jet-flow aeration oxidation ditch, and waste water is through post precipitation, again through filtering for the second time qualified discharge or reuse.Excess sludge can be used as farming fertilizer through concentrating moulding.

The present invention is in the entire treatment technical process, and annual needs potassium aluminium sulfate and the coagulant aids PAM2～4PPM at the 0.25Kg of every cubic metre of coagulative precipitation tank input in January, February and three months December, only account for 1 15 of general treatment process dosage.

Be described further below in conjunction with the technical process accompanying drawing:

(1) is comprehensive leather waste water in the accompanying drawing, and (2) are grating tank, and (3) are the anaerobism equalizing tank, (4) be the air supporting tower, (5) are filtration tank, and (6) are oxidation ditch, (7) be coagulative precipitation tank, (8) be sand filter, (9) are the mud upgrading tower, and reflux for mud (10), (11) reflux for sand filter mud, (12) be reuse or discharging, (13) are the mud compressed moulding, and (14) are outward transport.

Supernatant liquor and the sulfur-bearing choline of the chromate waste water of production plant etc. after reclaiming chromium mud, lime waste water merges into comprehensive leather waste water (1) through the waste water of preliminary precipitation processing and the waste water of other each production technique, remove lint and bulk scurf through thickness grating tank (2), behind the grease, send into anaerobism equalizing tank (3) and carry out anaerobic treatment, make the COD clearance about 15%, with pump the waste water floating tower (4) of supplying gas is carried out the aeration oxidation again, the clearance that makes COD is about 20%, suspended substance is sent into mud upgrading tower (9), send into filtration tank (5) with pump extracting waste water simultaneously, make waste water the time after filtration with physical treatment, carry out the microbial film effect simultaneously, and then the COD clearance is remained on about 15%.The part backwashing water is sent into mud upgrading tower (9) waste water after filtering, and to flow into form ratio be 1: 3 oxidation ditch (6), carry out jet aeration, make the COD clearance keep about 60%, the waste water of aeration after 5 hours is pumped to coagulative precipitation tank (7) with pump, in the pond, are added potassium aluminium sulfate 0.25Kg/M in this pond annual as long as January, February, December ³Behind coagulant aids PAM2～4PPM, all can carry out the solid-liquid separation effect whole year.Waste water inflow sand filter (8) through post precipitation sinks clearly, makes its whole qualified discharges or reuse (12).Waste water is through the precipitating sludge of coagulative precipitation tank (7) and the mud of sand filter (8), be back to oxidation ditch (6) and carry out the jet aeration oxidation again, and the mud of surplus and filtration tank (5) backwashing water, the suspended substance liquid of air supporting tower (4) is compiled in mud upgrading tower (9) with pump, supernatant liquor after concentrating flows into oxidation ditch (6), and the mud after concentrating makes water ratio in outward transport below 80% with pressure filter pressure filtration molding (13), or uses as the fertile raw material of organic farming after adding small amount of carbon ash or lime.

Use this technology, class can be produced 800 cubic metres in sewage, pH value 12～13, every liter of leather waste water that contains SS3500 milligram, COD2700～3000 milligram, BOD1350～1500 milligram reduces to pH value 6～7, every liter of SS is less than 230 milligrams, BOD less than 70 milligrams, COD and is less than 60 milligrams emission standard.Owing to have only January, February, dispensing in three months December every year, not only annual saving medicament expense is more than 90%, also lack about 30% than the common process capital cost, simultaneously 50% above waste water can reuse, its throw out is compressed, it is fertile also to can be used as organic farming after the dehydration moulding, and treatment station also can significantly reduce managerial personnel.Use the present invention and not only make environment obtain fine improvement, it is unified that economic benefit and social benefit are obtained.So can satisfy the leather waste water of all kinds tannery handles.

Claims

1, a kind of flow process of leather waste water treatment technique is: comprehensive wastewater → grating tank → anaerobism equalizing tank → air supporting tower → filtration tank → oxidation ditch → coagulative precipitation tank → sand filter → reuse or discharging, or operate agricultural fertile raw material outward by coagulative precipitation tank → mud upgrading tower → pressure filtration molding, it is characterized in that:

A, the totally enclosed anaerobism equalizing tank of this process using;

The form ratio of oxidation ditch is 1: 3 in b, this technology;

C, this technical process dosage are percent 15 of general technology, and every year, only input amount was potassium aluminium sulfate 0.25Kg/M to the coagulative precipitation tank dispensing in January, February, three months December ³, coagulant aids PAM2-4PPM, every liter of reaction optimum value PH6-7, SS are little less than 70 milligrams, COD, in 230 milligrams, BOD less than 60 milligrams.

When making the fertile raw material of organic farming, 2, technology according to claim 1, the precipitation body refuse after it is characterized in that handling adds small amount of carbon ash or lime.