CN1309097A

CN1309097A - Process for treating sewage of oil recovery

Info

Publication number: CN1309097A
Application number: CN 00133630
Authority: CN
Inventors: 杨主民; 季民; 陈卫东
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-11-30
Filing date: 2000-11-30
Publication date: 2001-08-22
Anticipated expiration: 2020-11-30
Also published as: CN1162360C

Abstract

A process for treating the sewage from petroleum recovery includes demoving oil from the sewage at tank bottom by tilted plate deoiling tank, floatation, buffering, adding filter assistant, straining, filtering, treating in suspending and adsorbing anaerobic oxidizing pool, intermediate settling, treating in suspending and absorbing aerobic oxidizing pool, settling, adding disinfectant and back injection. The aerobic mud from secondary settling pool is returned back to suspending and anaerobic oxidizing pool.

Description

Extraction wastewater treatment method

The present invention relates to a kind of sewage treatment process of recover petroleum.

Oil-contaminated water of oil field is come out by exploitation with crude oil from the stratum, and the waste water after gas-oil separation, dehydration is oil extraction-generated waste water, claims recovered water or oily(waste)water again.Not only contain crude oil in the oil extraction-generated waste water, also dissolve into various salts, suspended substance, obnoxious flavour, organism and a large amount of suspended solids; In oil-gas gathering and transportation and treating processes, also can mix the theory of evolution medicament.The COD concentration of oil extraction-generated waste water is not high, but BOD ₅/ COD value is very low, and only about 0.15.It is a kind of special organic wastewater with difficult degradation thereby.

Handling oil extraction waste water has physico-chemical processes, as electrodialysis, reverse osmosis, electrolysis, activated carbon adsorption, membrane sepn; Or chemical method, as various chemical oxidization methods, coagulating sedimentation or air supporting etc.; Also has biological process.The general processing efficiency height of physico-chemical processes, but investment is big, and the processing costs height requires the level of management height, is suitable for the little water yield and handles.Chemical method has application in some oil field, to bio-refractory waste water, better processing efficiency is arranged, but the outstanding defective of chemical method need add a large amount of chemical agents when being processing, as efficient organic or inorganic polymer medicament, processing efficiency height, the mud amount that produces is less, but daily processing working cost is high; As using more cheap lime, processing costs descends to some extent, but the body refuse that produces is too many, when disposing of sewage, bring secondary pollution, and the Working environment sanitary condition extreme difference of lime digestion and dosing system, the general operation personnel are unwilling to be difficult to guarantee system's works better in this post.Biological process is comparatively effective and economical to treatment of Organic Wastewater, as ordinary activated sludge, biological absorption, complete mixed biologic aeration, oxidation ditch, oxidation pond, bio-contact oxidation, blodisc, biological filter, anaerobism contact, anaerobic filter, up-flow anaerobic sludge blanket etc., but only depend on biological process that the sewage disposal in the oil production also is difficult to play a role.

The sewage works of present operation, the purification process that adopt based on the physics method more, can remove the oil pollutant in the sewage preferably, its technical process is: big jar end water → swash plate removes oil tank oil removing → flotation machine → surge tank → coarse filtration → finly filtration → re-injection or effluxes.The deficiencies in the prior art part mainly is: technology is more backward, handle back sewage with oil≤15mg/L, clearance and sterilization poor ability to COD, COD is up to 622mg/L, minimum 183mg/L, average 364mg/L, can not satisfy the requirement of GB8978-96 " integrated wastewater discharge standard ", the indexs such as COD, bacterium and suspended substance of handling the back water outlet can not reach produced-water reinjection standard (SY/T5329-94), directly efflux to cause detrimentally affect to surrounding environment; Efficient is low in addition, dynamically produces, data variation is big, and the treatment effect instability can directly be damaged the economic benefit and the social benefit in oil field.

The objective of the invention is to avoid weak point of the prior art, and a kind of technology advanced person is provided, processing efficiency height, working stability meet the extraction wastewater treatment method of national sewage comprehensive emission standard.

Can take following technical scheme to realize purpose.The technical process of this extraction wastewater treatment method comprises that big jar of end water removes the oil tank oil removing through swash plate, flotation, buffering, coarse filtration, finly filtration, re-injection; Before coarse filtration, establish flocculating aids and add a little, establish sterilant behind the finly filtration before the re-injection and add snack made with traditional Chinese medicines; Water is handled through suspending, adhere to the anaerobism contact-oxidation pool behind the finly filtration, intermediate sedimentation, suspend, adhere to aerobic oxidation pond is handled and secondary sedimentation after efflux; The anaerobic sludge in intermediate sedimentation pond and the aerobic sludge of secondary sedimentation basins are back to the import of suspension, anaerobism contact-oxidation pool; Intermediate sedimentation pond excess sludge is through concentrating, and mechanical dehydration is handled the back outward transport.

The relative prior art of the technical program has following advantage and effect:

Technology advanced person, the processing efficiency height, take up an area of less, the working cost low (＜0.5 yuan/m3 waste water) of reduced investment, processing unit's waste water, energy consumption is low, treatment effect is stable, operational administrative is easy reliably, good economy performance.Through trial run, the sewage after the processing reaches the requirement of GB8978-96 " integrated wastewater discharge standard " and oil field re-injection standard (SY/T5329-94).

PH=6-9; Oil≤5mg/L; COD≤100mg/L;

Suspended substance≤200mg/L; Sulfide≤1.0mg/L;

B0D5≤30mg/L; Volatile phenol≤0.5mg/L;

Prussiate≤0.5mg/L; Sexavalent chrome≤0.5mg/L;

Arsenic≤0.5mg/L; Fluorochemical≤10mg/L.The construction of this sewage treatment facility has solved the difficult problem that oil extraction waste water is handled.

In conjunction with the accompanying drawings, embodiment is described in further detail the content of the technical program.

Accompanying drawing is the process flow sheet of extraction wastewater treatment method.

Extraction wastewater treatment method, technical process is made of the two parts.The one, physics method de-oiling is in advance handled, its technical process: big jar of end water removes the oil tank oil removing through swash plate, flotation, and buffering, coarse filtration, finly filtration, re-injection is handled, and establishes flocculating aids add a little before coarse filtration, establishes sterilant after the outer draining of finly filtration and adds snack made with traditional Chinese medicines.The 2nd, anaerobism-Yu oxygen series connection biochemical treatment, its technical process: water is handled through the anaerobism contact-oxidation pool that suspends, adheres to behind the finly filtration, intermediate sedimentation, suspend, adhere to aerobic oxidation pond is handled and secondary sedimentation after efflux; The anaerobic sludge in intermediate sedimentation pond and the aerobic sludge of secondary sedimentation basins are back to the import of suspension, anaerobism contact-oxidation pool; The excess sludge in intermediate sedimentation pond is through concentrating, and mechanical dehydration is handled the back outward transport.

Sterilant adds snack made with traditional Chinese medicines, and generally the impact type dosing once got final product in each 4 hours weekly.Flocculating aids adds a little, generally speaking, and not dosing when filter back water oil-containing and indicator of suspended solids are qualified, when coming the water yield to increase suddenly or come water water quality abominable, thereby when causing filtering back water oil-containing and suspension content and exceeding standard, add an amount of flocculating aids, to improve filtration efficiency, guarantee that effluent quality is qualified.

Organic oil extraction waste water to difficult degradation only depends on the processing of anaerobism contact tank, and COD still can not reach sewage drainage standard, uses anaerobic-aerobic series connection biological treatment the most effective, and economical.Because of in the anaerobic and aerobic pond, there are two kinds of microbial populations simultaneously: suspension active sludge and sessile organism film.The anaerobic pond biochemical reaction is controlled at the acidication stage, and suspended sludge and biofilm microorganisms group can hydrolysis in the pond, the zymogenic bacteria group is main.The aerobic oxidation pond of normal operation, protozoon is active in the active sludge, and zoogloea is closely knit.In the anaerobism contact tank, organism through the acidication process, can be converted into the organism of difficult degradation the organism of easy degraded under the effect of acidication bacterium and facultative anaerobe.As macromolecular organic chemicals, be converted into low-molecular-weight simple organics such as short chain fatty acid, alcohols, aldehydes, the biological biodegradability of anaerobic pond water outlet is improved.Aerobic bacteria further is decomposed into inorganics, CO to the oxidation operation that these are easily degraded in Yu oxygen oxidation pond ₂And water.Because have very high biomass in the system, this technology has the good treatment effect to organic wastewater with difficult degradation thereby, be practicality, economy and the effective advanced technologies of handling various organic wastewater with difficult degradation thereby at present.In technology, the second pond residual sludge reflux is arrived the anaerobism contact tank, make mud carry out anaerobic digestion, thereby can reduce the excess sludge discharge amount of system, make the sludge quantity of processing reduce to minimum degree, thereby save the sludge treatment expense greatly.

Less because of anaerobic-aerobic Sewage treatment systems sludge output, calculate according to sewage quality, handle 3000m ³The sewage of/d, the about 1-3m of mud of generation water ratio 80% ³The excess sludge unification of sewage biological treatment system is discharged by anaerobic pond, is earlier that 99.6% excess sludge enters in 1 gravity concentration basin with water ratio, is concentrated to water ratio 95-97%, enter the mechanical dehydration machine again, be dewatered to water ratio 80% dried mud, transport outside the factory, fertile or fill out the hole as farming.Select for use one in mechanical dehydration machine to meet the demands.Can build 1 of sludge dewatering pump house.

In the extraction wastewater treatment method:

Suspend, adhere to be provided with in the anaerobism contact-oxidation pool low density elastic solid filler, load volume be the pond hold 2/3, dress diving mixer at the bottom of the pond.For keeping having in the pond suspended biological mud of q.s, suspended sludge concentration maintains 5000-8000mg/L in the pond, and control return sludge ratio 20-30% is good.Aerobic excess sludge enters in the anaerobic pond, can reduce total sludge volume of system.Diving mixer is set can makes the suspended state biological sludge in the pond can both be in good suspended state, the contacting and mass transfer of pollutent in enhanced biological mud and the sewage improved processing efficiency.Settled organism is raised growth on filler, and degradable organic pollutant is based on settled organism mud.The existing various fillers that are used for water and wastewater treatment, having his own strong points also respectively has it short.The easy obstruction that has, the usually conglomeration that has, especially under anaerobic state, conglomeration and blockage problem are more serious.The carrier biofilm that has adheres to difficulty, and the specific surface area that has is less, and the construction costs that has is too high.Elastic solid filler be a kind ofly do not stop up, not conglomeration, long film and demoulding be all than the filler that is easier to, price is low, the life-span is long, it is a filler very practical, economic in the bio membrane process.Consider that the waterpower stirring extent relaxes in the anaerobic reation pool, in anaerobic pond, select the low-density elastic solid filler of commercially available TA type.

Intermediate sedimentation adopts gravity spoil disposal vertical sedimentation tank, the Chi Zhongshe sludge reflux pump of diving under water.The intermediate sedimentation pond can be built jointly with anaerobic pond, and is more economical.

Suspend, adhere to density elastic solid filler in being provided with in the aerobic oxidation pond, load volume and be that the pond holds 2/3, variable microporous aeration device-pipe is set at the bottom of the pond.A plurality of Aerobic Pond multiple operations can be set, return sludge ratio 20-40%, suspended sludge concentration 2000-3000mg/L in the pond, evenly arrange the threaded hole aeration flexible pipe with choke preventing function and high oxygenation capacity, gas-water ratio at the bottom of the pond: 12: 1, blast volume: 1500m ³/ h, blast 49kPa are good.Elastic solid filler has multi-level cutting power to bubble in aeration process, can improve oxygen-transfer efficiency, saves power consumption.Variable micropore aeration pipe oxygen transfer efficiency height, be difficult for to stop up, cost is low, be convenient to maintenance management.

Keep in anaerobic pond and the Aerobic Pond greatly having strengthened processing power, strengthened the performance of the anti impulsion load of facility than the high a lot of biomass of general contact oxidation method.

Tube settler is adopted in secondary sedimentation, and the diving sludge reflux pump is set in the pond.Many be built, be built to second pond can jointly with Aerobic Pond.

Claims

1, a kind of extraction wastewater treatment method, technical process comprise that big jar of end water removes the oil tank oil removing through swash plate, flotation, and buffering, coarse filtration, finly filtration, re-injection is characterized in that: established flocculating aids and add a little before coarse filtration, establish sterilant behind the finly filtration before the re-injection and add snack made with traditional Chinese medicines; Water is handled through suspending, adhere to the anaerobism contact-oxidation pool behind the finly filtration, intermediate sedimentation, suspend, adhere to aerobic oxidation pond is handled and secondary sedimentation after efflux; The anaerobic sludge in intermediate sedimentation pond and the aerobic sludge of secondary sedimentation basins are back to the import of suspension, anaerobism contact-oxidation pool; The excess sludge in intermediate sedimentation pond is through concentrating, and mechanical dehydration is handled the back outward transport.

2, extraction wastewater treatment method as claimed in claim 1 is characterized in that:

Suspend, adhere to be provided with in the anaerobism contact-oxidation pool low density elastic solid filler, load volume be the pond hold 2/3, dress diving mixer at the bottom of the pond;

Intermediate sedimentation adopts gravity spoil disposal vertical sedimentation tank, the Chi Zhongshe sludge reflux pump of diving under water;

Suspend, adhere to density elastic solid filler in being provided with in the aerobic oxidation pond, load volume and be that the pond holds 2/3, variable microporous aeration device is set at the bottom of the pond;

Tube settler is adopted in secondary sedimentation, and the diving sludge reflux pump is set in the pond.