CN101223111B

CN101223111B - Apparatus and method for treating fgd blowdown or similar liquids

Info

Publication number: CN101223111B
Application number: CN2006800262296A
Authority: CN
Inventors: 杰弗里·G·皮特斯; 威廉·A·邦科斯基; 皮埃尔·L·科特; 希达亚特·胡塞恩; 蒂莫西·M·皮克特
Original assignee: Zenon Technology Partnership
Current assignee: Zenon Technology Partnership
Priority date: 2005-07-25
Filing date: 2006-07-24
Publication date: 2012-06-27
Anticipated expiration: 2026-07-24
Also published as: CA2942941C; CA2942941A1; CA2517322C; CN101223111A; SI1910234T1; ES2396241T3; CA2517322A1

Abstract

A process has steps of one or more of aerobic treatment to remove COD and nitrify a waste stream, anoxic treatment to denitrify a waste stream, anoxic treatment to remove selenium and anaerobic treatment to remove heavy metals and sulphur. The process may be used to treat, for example, FGD blow down water. The process may further include one or more of (a) membrane separation of the waste stream upstream of the anoxic digestion to remove selenium, (b) dilution upstream of the biological treatment step, (c) physical/chemical pretreatment upstream of the biological processes or dilution step to remove TSS and soften the waste stream, or (d) ammonia stripping upstream of the biological treatment steps or dilutions step. These processes may be provided in a variety of suspended growth or fixed film reactors, for example a membrane bioreactor or a fixed film reactor having a GAC bed. Processes for biological treatment of inorganic compounds in a fixed medium reactor is described including steps of one or more of maintaining desired ORP levels, optionally by controlling nutrient addition, and removing solids or gas bubbles from the medium bed.

Description

The equipment of smoke treatment desulfurization blowdown or similar liquids and method

For the U.S., according to 35USC 119 (e), the application requires the right of U.S. Patent application of submitting on July 25th, 2,005 60/701,996 and the U.S. Patent application of submitting on November 16th, 2,005 60/736,859.The application requires the right of priority of the Canadian patent application 2,517,322 of submission on August 26th, 2005.The full text that is incorporated herein above-mentioned application as a reference.

Technical field

The present invention relates to water treatment, comprise biological water treatment and contain the processing of the feed (more for example from washer blowdown (blow down) water of coal-fired power plant's flue gas desulfurization (FGD) operation) of inorganic pollutant (for example selenium, nitrate radical or heavy metal).

Background technology

The discussion of following background technology does not also mean that or does not admit that following any method or equipment are prior art or are the part of any national those skilled in the art's general knowledge.

Washer sewer from coal-fired power plant's flue gas desulfurization operation contains a large amount of inorganic pollutants of from waste gas, deviating from.The ammonia a part of or that add in order to promote FGD to handle that sewer also possibly contain organic pollutant such as diprotic acid (DBC) and handle as FGD.FGD washer sewer can contain very many total dissolved solidss (total dissolved solid), and wherein main negatively charged ion is a cl ions, and main positively charged ion is calcium ion, mg ion and sodium ion.May command blowdown speed makes sewer have high and normally stable chlorine ion concentration to keep required chlorine ion concentration.Even owing in same power station, also can receive the influence of the coal of the different sources that for example burns, the concentration of other pollutent is about-face greatly.Yet; TDS, TSS, Ca and Mg hardness (hardness), nitrate radical, ammonia and sulphur (for example as vitriol) all possibly have high concentration; And possibly there is each heavy metal species, thereby makes the sewer intractable, particularly be difficult to realize extremely low Pollutant levels.The waste water that discharges in other waste water such as the mining, agricultural drainage or waste water, other service water or even tap water also possibly contain nonconforming some or all of these inorganic pollutants of concentration.

The method of discharged sewage treatment depends critically upon physics and chemical process removal inorganic pollutant at present.Physics and chemical process relate to expensive pharmaceutical chemicals and produce a large amount of mud.Under above regulation and control level, in sewer, possibly also there are arsenic, mercury and heavy metal.In addition, the selenium concentration in the draining that is discharged in the environment has been adjusted in some zones recently.The permissible concentration of selenium can be 0.5ppm or following or 200ppb or following, yet the selenium that sewer can contain 1-20 or 2-10ppm in traditional treatment unit is not removed.

At the disclosed United States Patent(USP) No. 6 that removes the selenium method by name on February 6 calendar year 2001; 183; Among 644 (D.Jack Adams and the Timothy M.Pickett); Through in the selenium reduction organism that contains selection area and other selenium reduce organic reactor drum, water being handled, remove the dissolved selenium in the polluted water.From specific water, isolate mikrobe or introduce mikrobe by other selenium contamination water.Sift out then and under local particular environment condition, can reduce the mikrobe of selenium.Reduction is best to selected mikrobe for selenium, then selected mikrobe is arranged in the high-density biology film in the reactor drum.Make selenium contamination water through reactor drum, this reactor drum contains the best nutritional mixture that adds as required.Be settled out simple substance selenium and it is removed from water.Utilize the goods of this method or similar approach can be available from the product of Salt Lake City, Utah, United States Applied Biosciences Corp registered trademark for ABMet .Be incorporated herein United States Patent(USP) No. 6,183,644 full text as a reference.

Summary of the invention

Following content is intended to introduce the present invention rather than limit the present invention to the reader.The present invention can be the combination of described one or more equipment components in any place of the application or process step.

The objective of the invention is the useful alternative that improves prior art or prior art is provided at least.The purpose of this invention is to provide method of wastewater treatment or equipment.Other purpose of the present invention provides and is used to handle FGD sewer or other method or equipment that contains selenium or nitrate radical or contain the waste water of the two simultaneously, the perhaps method or the equipment of the inorganic pollutant in the biological removal waste water (for example nitrogen, selenium, arsenic, mercury or sulphur).Waste water can be undressed waste water perhaps for passing through pretreated waste water.

The described method of the application may further comprise the steps: anaerobic is handled, so that useless stream is carried out denitration; Anaerobic is handled, to remove selenium; And anaerobic treatment, to remove heavy metal or sulphur or to remove the two simultaneously.The removal of heavy metal is feasible, and this is because there is SO ₄And through anaerobism SO ₄Reducing bacteria is with SO ₄Be converted into sulfide.One or more steps during this method is further comprising the steps of: (a) anaerobic digestion is flowed membrane sepn to remove give up before the selenium; (b) dilute before the biological treatment step; (c) carry out the physical/chemical pre-treatment before biological treatment or the dilution step; To remove TSS and softening useless stream; For example add lime or sulfide and disgorging, (d) carry out the ammonia stripping before biological treatment step or the dilution step or (e) carry out aerobic before anaerobic is handled and handle, to remove COD and to carry out nitrated useless stream.Some biological treatment steps can carry out in fixed-film reactor such as granular carbon bed.One or more steps in the biological treatment step also can be carried out in suspension growth reactor drum such as membrane bioreactor.Each biological treatment step can carry out in optimizing with the independently reactor drum that carries out treatment step, and perhaps two or more biological treatment steps can carry out in the multi-usage reactor drum.

The described equipment of the application is furnished with one or more reactor drums,, denitration nitrated to carry out through biological treatment, removal selenium and heavy metal and desulfurization.This equipment also can have the reactor drum that carries out the processing of COD aerobic.Said reactor drum can comprise membrane bioreactor or fixed-film reactor.Fixed-film reactor can comprise active-carbon bed or other carrier substance bed.This equipment also can have the inlet, the bio-reactor upper reaches that are used for diluting the biological treatment feedwater and be used for adding the one or more of lime or the system of sulfide, one or more physics or Chemical Pretreatment system, throw out remover or ammonia stripper to waste water.

Described equipment of the application or method also are used for removing the nitrate radical of fixed-film biological reactor.Described equipment of the application or method also provide the fixed-film biological reactor with two or more districts.Said zone can be used for removing different pollutents and can have different oxidation reduction potential (ORP).The control of described equipment of the application or method nutrition also capable of using position (nutrient location) or feed speed is the ORP in film or the medium bio-reactor fixedly.Described equipment of the application or method also are used for impacting fixedly film or medium bio-reactor to discharge media bed solid matter or bubble.

Described method of the application or equipment can be used for handling the FGD sewer or through pretreated FGD sewer, to produce the draining of selenium concentration low (for example 1ppm or following or 10ppb or following) and total nitrogen concentration low (for example 1mg/L or following or 10ppm or following).Yet when the selenium concentration in the draining was unimportant, described equipment of the application or method also can be applicable to discharged sewage treatment.The application's equipment or method also can be used for handling the waste water that other contains selenium or nitrate radical; For example mining or agricultural drainage or useless stream, contaminated underground or insulated stream or the useless stream of refinery, particularly useless stream also contains high concentration of COD, nitrate radical, ammonia, TDS, TSS, hardness, CaSO ₄Or one or more the situation in the sulfate radical.

Description of drawings

Below will be with reference to the embodiment of following description of drawings embodiment of the present invention.

Fig. 1 is the process flow diagram of water treating equipment and method.

Fig. 2 is the process flow diagram of another water treatment system.

Fig. 3 is the synoptic diagram of the partial alternate embodiment of system and method for demonstration Fig. 1 or Fig. 2.

Fig. 4 is the sectional view of bio-reactor.

Fig. 5 is for adopting the test-results chart of multi-stage biological reactor drum.

Fig. 6 is the test-results chart of relevant selenium reduction organism quantity and temperature relation.

Fig. 7 is the selenium reduction figure of FGD sewer when using DBA as carbon source.

Fig. 8 is for showing the chart that respectively reacts the ORP scope.

Fig. 9 is the process flow diagram of another water treatment system.

Embodiment

Below will describe, so that the instance of embodiment of the present invention to be provided various device or method.Following embodiment is determinate for right and wrong of the present invention, unaccounted technology or equipment below the present invention can cover.The invention is not restricted to have the equipment or the technology of following any one equipment or the whole characteristics of technology or be not limited to and following majority or armamentarium common characteristic.Following equipment or technology possibly not be embodiment of the present invention.All authority in any invention that applicant, contriver and everyone keep the presents failed call and the presents disclosure is not abandoned or in disclosed following equipment of the public or technology, do not disclose.

The supposition pollutent and the concentration thereof of FGD washer sewer in equipment that table 1 further specifies below showing and the embodiment of the method design.The FGD sewer can contain other pollutents or have other Pollutant levels.For specific coal-fired power plant, owing to receive the for example influence of coal source variation, the composition of FGD sewer also can big in time about-face.Yet the characteristic of FGD sewer totally is very high total dissolved solidss (TDS), and wherein main negatively charged ion is a cl ions, and main positively charged ion is calcium ion, mg ion and sodium ion.Sewer also contains the thin suspended solid material of high density, comprises CaSO ₄Fine particle.Sewer also contains a large amount of inorganic pollutants, comprises in the washing process for carrying out the ammonia that SCR adds.Sewer also can contain some organic substances, in particular for improving the DBA (diprotic acid) that washer efficient possibly added.In following equipment and method, the draining intention has 10ppm or following total nitrogen (TN) amount and 0.4ppm or following selenium concentration.

The representative FGD sewer of table 1

Parameter	Typical value	Minimum-maximum
			Cl ions	30000ppm	20-40000ppm
pH	＞5.0＜6.0
			TDS	75000mg/L	50000-150000mg/L
TSS
		2% dry weight	The 1-5% dry weight
Aluminium---total amount				960ppm	80-3700ppm

Antimony	12ppm	0.03-49.0ppm
			Ammonia---N	31ppm	0.25-64ppm
Nitrate radical---N	350ppm	200-450ppm
			Total nitrogen	200ppm	50-400ppm
Arsenic---total amount	15ppm	0.27-100ppm
			Barium---total amount	100ppm	2.0-770ppm
Beryllium	2.1ppm	0.06-6.9ppm
			Boron	-	20-40ppm
Cadmium---total amount	0.8ppm	0.12-1.5ppm
			Calcium	18000ppm	10000-30000ppm
Chromium---total amount	23ppm	0.5-210ppm
			Chromium VI	-	3-12ppm
Cobalt	-	0.05-4ppm
			Copper---total amount	1.7ppm	0.3-6.6ppm
CO ₃/HCO ₃	1500ppm	1-3000ppm
			Fluorion	360ppm	61-1600ppm
Iron---total amount	1400ppm	116-6400ppm
			Plumbous---total amount	19ppm	0.2-140ppm
Lithium	-	2-3ppm
			Magnesium	15000ppm	10000-20000ppm
Manganese	10ppm	3.6-200ppm
			Mercury---total amount	0.38ppm	0.5-1.4ppm
Nickel---total amount	10ppm	0.5-74ppm
			Phosphate radical---total amount	1.0ppm	0-10ppm
Potassium	6800ppm	5000-10000ppm
			Selenium---total amount	17ppm	1.5-100ppm
Silver---total amount	10.0ppm	0.002-20ppm
			Sodium	15000ppm	10000-20000ppm
Sulfate radical (SO ₄)	60000ppm	40000-80000ppm
			Thallium	0.76ppm	0.02-2.2ppm

Vanadium	-	1.0-11.0ppm
			Zinc---total amount	15.0ppm	1.7-50.0ppm
Temperature	130	125-130

In more detail, blowdown is handled and has been proposed several challenges, and promptly method or equipment can solve like the variety of way of following describe, in general terms, and the one or more embodiment through explanation treatment system and method solve then.In following explanation, pre-treatment is meant and occurs in biological treatment step processing before.

High TDS concentration makes and is difficult to keep the biological treatment activity.Can address this problem through the useless stream of dilution before biological treatment.High TDS also causes and in activated sludge is handled, is difficult to make biomass (biomass) flocculation and sedimentation.Through using fixed-film biological reactor or membrane bioreactor, address this problem, said reactor drum can move under the low TDS concentration of sedimentation capacity (settlability).

Usually, the high firmness that Ca or Mg supersaturation cause causes fouling (scaling), and any pH value or variation of temperature possibly cause the vitriol or the carbonate deposition of calcium or magnesium.FGD can contain sulfate radical, calcium and the magnesium that causes scaling condition dangerous in a large number with other trade effluents, and this fouling situation is aggravated along with the enhancing of alkalescence.Cause alkalescence when removing nitrate radical through biological denitrification, this often encourages fouling in some steps.Can through softening pre-treatment such as lime be softening and randomly through before biological treatment, adding acid for adjusting pH value, address these problems.Be described below, also can or also can solve fouling through in fixed-film reactor, carrying out biological denitrification.The pH value can flow through the direction reduction of said reactor drum along feed, thereby makes said reactor drum resistive connection dirt.Particularly, the selenium of in reactor drum, breeding also pathogenic microorganism or other mikrobes can be through supplying to produce organic acid with the fermentation of the nutritive substance of system, thus neutralization alkalescence and suppress fouling.

Along with the formation of suspended biological matter and the obstruction of control and bio-reactor and film, high TSS particularly because TSS is essentially inorganics, causes going wrong.Can solve said problem through useless stream is carried out pre-treatment so that suspended solid material condenses or flocculate also physical removal (for example through sedimentation or floating) subsequently.

High nitrate concentration is important, and this is because nitrate radical is the preferred biological reducing electron acceptor(EA) that is superior to selenate radical.Can address this problem through before the selenate radical reduction step, reducing the concentration of nitrate radical.The reducing nitrate radical step can occur in the upstream portion of selenate radical reduction reactor; As selenate radical reduction handle or part before multistep biological treatment or the part of the fixed-film reactor formed by several parts, perhaps as the part of independent processing or reactor drum.

Ammonia in the sewer is important, and this is because the concentration in the final draining is adjustable and oxidation ammonia can increase the concentration of nitrate radical.For example through in pre-treatment step, being NH with the ammonia stripping ₃Remove ammonia, or, address this problem through in series of steps or along with circulating, carrying out the biological ammonia that removes of nitrated/denitration processing.Denitration (denitrification step in handling as nitrated/denitration or remove the nitrate radical that ammonia oxidation forms) can be carried out in fixed-film biological reactor, and said fixed-film biological reactor can be the part of single selenium reduction bio-reactor or reduces the part of bio-reactor for the selenium of being made up of several parts.

The existence of each heavy metal species such as Cu, As or Hg or relevant oxidize contaminants is important, and this is because said each heavy metal species or relevant oxidize contaminants are adjustable in draining, but concentration is difficult to remove when low.Can be through in the softening step of pre-treatment, being settled out these elements, part addresses this problem.Also can be through biological reducing SO after removing nitrate radical, selenate radical and selenite radical ₄And be settled out these metallic sulfide pollutents, address this problem.Deposition can be carried out in fixed-film biological reactor, and said fixed-film biological reactor can be the part of single selenium reduction bio-reactor or reduces the part of bio-reactor for the selenium of being made up of several parts.

Selenium as selenate radical or selenite radical existence is important, and this is because of direct or indirect up-to-date regulation to selenium concentration in the draining, the regulation of for example carrying out through the fish tissue concentration that receives in the body.Selenium is difficult to remove, and this is because the concentration of selenium is low and be tending towards forming selenate radical or selenite radical and water-soluble, thereby it is low to make physics or chemistry remove difficulty, costliness or efficient.Through biological reducing is simple substance selenium, then its deposition is removed, and comes the selenium in treatment process and the equipment.The removal of above-mentioned selenium can be carried out in fixed-film biological reactor, and said fixed-film biological reactor also can be used for removing other pollutent.

Fig. 1 is presented at the treatment system 10 that regional 14 upper reaches of biological treatment have pretreatment zone 12.Feed 16 (can be FGD sewer or other feed) flows into pretreatment zone 12.In pretreatment zone 12, remove the most of TSS in the feed, and remove Ca and Mg with softening feed 16.Pretreatment zone 12 adopts the physical/chemical method to handle feed 16.For example, can or simultaneously the two be added in the feed 16 lime or sulfide, with precipitated calcium, magnesium and metal.Can pass through settler for example single-stage or twin-stage settler disgorging.Can promote sedimentation through adding condensing agent or polymkeric substance.

The pre-treatment draining is left pretreatment zone 12 through pre-treatment water shoot 20.Add dilution water 18 to the pre-treatment draining.Dilution water 18 has reduced total dissolved solidss (TDS) concentration of pre-treatment draining, thereby makes said pre-treatment draining be applicable to the biological treatment in downstream.Macrodilution water 18 be can add,, 35g/L or following TDS for example contained so that TDS concentration is similar to the TDS concentration of seawater.Any low TDS water all can be used for dilution water 18, for example the refrigeration cycle sewer in power station.Dilution water 18 also cools off the FGD sewer, for example from 50 ℃ or abovely be cooled to about 43 ℃ or following or 40 ℃ or following, thereby helps biological treatment more.As shown in Figure 6, about more than 43 ℃, selenium reduces organic healthy state and descends.Usually, fixed-film reactor can about 40 ～about 105

down work.Special reactor drum (established reactor) but short period of time withstand higher temperatures also, for example tolerate 110

24 hours at the most.

Diluted then pre-treatment draining flows to biological treatment zone 14.Biological treatment zone 14 has four districts: aerobic district 22; The first anaerobic district 24; The second anaerobic district 26; With anaerobic zone 28.As shown in Figure 1, said

section

22,24,26,28 polyphones connect, but the one or more also replaceabilities ground in the said section is connected with circulation loop.Replaceability ground in addition, some in the

section

22,24,26,28 possibly not need in some

embodiments.Section

22,24,26,28 can be present in independently in the reactor drum, perhaps one or more also can be combined in the reactor drum in the

section

22,24,26,28.One or many in the

nutritional flow

30,32,34 capable of using directly or through any

section

24,26,28 of

intermediate zone

24,26 to

nutritional flow

30,32,34 downstream is added nutritive substance.For example, can or flow and add nutritive substance in 32, with the growth of sector 26 or section 28 or the bacterium in the two to stream 30.

That aerobic district 22 is used for is nitrated, assimilation (assimilate) or remove deammoniation, reaches ammonia not steam stripped degree in pretreatment zone 12, and is used for the oxidation organic carbon.Also can increase optional additional aerobic district in anaerobic zone 28 downstream, with remove before the

section

24,26,28 or among lingering section and the residual compounds of oxidation anaerobic zone 28 of the nutritive substance that adds.If do not have the TN emission limit set for draining, perhaps in pretreatment zone 12, make the TN in the draining meet the requirements the ammonia stripping, can omit aerobic district 22 so, aerobic district that perhaps can anaerobic zone 28 downstream replaces aerobic district 22.

In the first anaerobic district 24, nitrate radical is the preferred electron acceptor and is removed through denitration.In view of the nitrate radical that uses high density is superior to using the selenate radical or the selenite radical of lower concentration as electron acceptor(EA), can remove nitrate radical, make it reach the concentration that helps in the second anaerobic district 26, carrying out biological reducing selenium.For example, in the flow of leaving the first anaerobic district 24, NO ₃Can be reduced to 10mg/L or following (pressing N calculates) or 1mg/L or following (pressing N calculates) or 10ppm or following (pressing N calculates).

In the second anaerobic district 26, through biological reducing and removal, for example enter into flushing current or waste residue through deposition, remove selenium.For example can be according to United States Patent(USP) No. 6,183,644 described methods or other fix or suspended-bed reactor in carry out these steps.Said reactor drum can have been inoculated selenium reduction organism.

In anaerobic zone 28, sulfate radical reducing bacteria reduced sulphur acid group also generates H ₂S or HS ^-The sulfide of form.Section H S ^-Can form the non-solubility metallic sulfide with the soluble metal reaction, said non-solubility metallic sulfide can be precipitated out from solution.Anaerobic zone is removed heavy metal by this way.Waste gas from anaerobism step 28 can be recycled to the perhaps aerobic step in downstream of aerobic step 22, follows H with minimizing ₂The smell that S produces.

Usually, can

section

22,24,26,28 be arranged in one or more reactor drums.The reactor drum that each

section

22,24,26,28 can occupy separately for example carries out optimization to reduce the original object pollutent of each

section

22,24,26,28 to CSTR.Perhaps, for example, can

section

22 and 24 be combined to can have one, the combination of two or more grooves is nitrated/Benitration reactor in.

Can section

24,26 and 28 or 26 and 28 be combined among the ABMet or other fixed-film reactor with one or more grooves.Also can use other reactor drum.For the suspension growth reactor drum, the limiting concentration of target contaminant maybe be lower and existence other pollutent possibly make the separation difficulty of biomass, thereby membrane bioreactor is preferred.Perhaps; Can use fixed-film reactor, for example the moving-bed bioreactor produced of Norway AnoxKaldnes, sulfuration bed bioreactor that for example N.J. Shaw Envirogen produces, for example the French Degremont registered trademark of producing be the biofilter of BIOFOR, registered trademark that for example Utah, USA Applied Biosciences Corp. produces be ABMet the granular carbon reactor drum, or as PCT openly the film described in No.WO 2004/071973 or the WO2005/016826 carry biofilm reactor (membrane supported biofilmreactor) (MSBR).Of Canadian patent application No.CA 2,477,333, MSBR can move according to section autotrophy or the optional non-autotrophy of non-autotrophy method of denitration of utilizing.Can randomly utilize membrane sepn, but also possibly need not to use membrane sepn with any fixed-film reactor or after any fixed-film reactor.Be incorporated herein WO 2004/071973, WO 2005/016826 and CA 2,477,333 full text separately as a reference.

Fig. 2 demonstration is used for the for example process flow sheet of the treatment unit 50 of processing list 1 said FGD blowdown.In pretreatment zone 12,, carry out pre-treatment through softening and in settler, carry out one-level or secondary sedimentation at the optional lime that carries out when adding sulfide.This technology can be provided by Utah, USA WesTech or other company.When adding dilution water 18, the pH value in the pre-treatment draining 20 is adjusted to less than 8.5, for example between 6 to 8, to promote biological treatment.In aerobic district 22, the membrane bioreactor with aerobic groove and film groove can be used for nitrated, and said film groove comprises ZeeWeed (TM) film available from GEWater and Process Technologies, Ontario, Canada Zenon Membrane Solutions.Replaceability ground can omit aerobic district 22.The first and second

anaerobic districts

24,26 and anaerobic zone 28 can be arranged in ABMet reactor assembly that Utah, USA Applied Bioscience Corp. produces, and perhaps are arranged in the similar or improvement system that can be made up of secondary or staged reactor.Said reactor drum is the upflowing fixed-film reactor, and this reactor drum uses the GAC bed with the operation of plug flow form, thereby can set up the biotic district corresponding to the first anaerobic district 24, the second anaerobic district 26 and anaerobic zone 28 successively.Replaceability ground can use downflow reactor.Can use a nutritional flow 30 at the ABMet reactor drum upper reaches.Perhaps, if use secondary or staged reactor, the nutritive substance inlet can be arranged on one or more levels perhaps upper reaches at different levels so, but needn't supply with nutritive substance through each inlet always.Through periodic flushing GAC bed throw out is moved to overflow trough from this reactor drum.The mud in pretreatment zone 12 and biological treatment zone 14 is delivered to sludge thickener and water trap.To drop into waste material through the mud of multiviscosisty and dehydration.Make sludge thickening and dehydration draining return homogenization groove (equalization tank), to mix with FGD blowdown feedwater 16.The use of ABMet method or equipment below will further be discussed, perhaps can comprise the use of medium filter of improvement or the raising of said method or equipment usually.

Can ABMet reactor drum be described as upflowing or the growth of downflow system simple fixation or fluidisation gac or other mounting medium base biological filter system or bio-reactor.The cross section of sample product reactor 100 is as shown in Figure 4.Be provided with media bedly 101, the selected microorganism crowd will grow on this is media bed and be retained in the system.Gac can be used as medium and the very large surface-area that is suitable for microorganism growth is provided.For example the form of granular carbon or spheric active carbon provides gac.Can use other medium, for example polymer fiber, rubble, float stone, sand, plastic medium or gravel.For gac, the most surfaces locality protection is in each intragranular crack, charcoal end, thereby the protection biomass make it avoid shearing force and frictional force.Media bed 101 can occupy the section h2 of reactor drum 100.

The proportion of having the activated carbon granule of biomass is a bit larger tham 1.0.Said particle can have the hydrostatic settling velocity of about 160ft/hr.The contriver notices that the settling velocity of activated carbon granule is identical with the settling velocity of granular sludge in upflow type anaerobic sludge blanket (UASB) system, therefore inject feed proportioning system (influentdistribution system) and normal following current state during the interior water pressure conditions of carbon bed can be identical with the UASB system.

Reactor drum can have port 106, lower port 102 and backwash port one 03, and said each port can link to each other with batching or the for example one or more level pipes of gathering system 105.Randomly, for some systems, lower port 102 can link to each other with same batching or gathering system 105 with backwash port one 03 simultaneously, perhaps can be by a port and batching or gathering system 105 replacements.Uniformly the hole can suitable spacing be positioned at the downside of these pipes.Can the pressure drop in said hole be designed to about 1.0psi, thereby make and to ignore and to guarantee uniform Flow Distribution along the frictionloss of each pipe.Can pass through various header boxs or manifold together with a plurality of pipe coupling.One or more levels aggregate (aggregate) 104 can be arranged on one or more batchings or gathering system 105 among the end packing layer h1 around with above.Aggregate 104 will assist shunting also will prevent simultaneously medium bleed the batching or gathering system 105.If needed, the system 105 that links to each other with port 106 can be hidden in the screen cloth or have aperture as required and get into to prevent medium.Waste water can be from the top or the bottom get into media bed 101.Waste water can get into reactor drums 100 through port 106, is downward through media bed 101 and from lower port 101 it is drawn.Perhaps, waste water can get into through lower port 102, upwards flows through media bed 101 and also flows out through port 106.Under normal following current condition, upper reaches speed can be maintained at about 5ft/hr, far below the settling velocity 160ft/hr of gac.

At normal operation period, solid matter will be deposited in media bed 101.These solid matters can be one or more in following three kinds of materials: the TSS that 1) gets into reactor drum 100 and remain; 2) be fixed on biomass on the medium; The growth of this biomass also occupies other space and 3) bio-transformation is solid-state and is retained in the inorganic pollutant in the bed.

Along with the accumulation of solid matter, media bed 101 interior pressure drops improve.The timed interval that can select or pressure spot (pressure point) flushing medium bed.Backwash port one 03 capable of using and relevant batching or gathering system 105 are accomplished aforesaid operations.In this case, can keep the feed of about 80ft/hr or feedwater upper reaches speed to come flushing medium bed 101.Can adopt other speed, for example the speed in the velocity range of active carbon fluid bed system employing.

The upper reaches speed that adopts in the flushing process can cause media bed upwards the expansion to get into bed expanding layer h3 up to 30%.Can this speed fluidisation media particle, thus the overgrowth of the biomass that capture the deposition of injecting TSS (trapped infiuentTSS), invest medium and the relevant inorganic pollutant of having removed or being precipitated out from waste water from waste water caused.Used upper reaches speed still is significantly less than the settling velocity of media particle.Therefore, in this operating process, can be from bio-reactor the nonconforming medium of the amount of going out.Can remove wash-down water and entrained solid material through groove 108.Can in flushing process, close the port 106 or the lower port 102 that are used to extract treated draining.

Headspace layer h4 be arranged on the expanding layer h3 and layer h5 in reactor cap 109 under.The gas that mikrobe discharges can be collected among the headspace layer h4.Venting hole or air outlet 110 among headspace h4 or the lid h5 can be used for said gas release in atmosphere, perhaps collecting said gas, for example in downstream branch technology or through being recycled to system's upstream portion, said gas are further handled.

From the viewpoint of hydraulic pressure design, during sending to the upper reaches (if existence), reactor drum 100 can move under the state that is similar to the UASB system, and between flush period, reactor drum 100 can be similar to operation under the state of biological fluidized bed.Under the situation that the upstream process step is normally carried out and suppose that the biomass in media bed 101 have the low speed of growth, can only wash several times every year from requiring per two weeks flushing once to become requirement, for example one month once.Flushing can be the batchwise operation that lasts 30 minutes.The exhausted wash-down water can turn back to the device front portion, and is for example anterior from said device, solid matter will be in solid contact settler sedimentation and final and the original solid matter blend that is used to dewater and handle.Perhaps because the solid matter gone out from reactor drum 100 possibly contain selenium and heavy metal, so but the individual curing wash-down water carry out independent aftertreatment or solid disposed to isolate solid matter.

Except above-mentioned flushing or replace above-mentioned flushing, can be periodically or " impacts " perhaps fluidisation or backwash reactor drum 100 in short-term every now and then.Can pass through the mixture of current (for example reactor drum 100 feedwater, water coolant or tap water) or gas (like air), bubble and water,,, impact to be higher than the normal upwards speed of velocity of approach through backwash port one 03.Can about 1gpm/ft ²～14gpm/ft ²Speed carry out the short period of time (for example 10 minutes or following or 5 minutes or following) impact.Can be for example per hour once impact to the frequency of weekly (for example every day 1 to 4 time).Impact makes media bed 101 to expand, and can some solid matters be removed from system, also discharges and accumulates in the bubble in media bed 101.Bubble in media bed 101 or solid matter can hinder and run through media bed 101 and flow.Therefore, ballistic main purpose is to control head loss (head loss), particularly through discharging the bubble in media bed 101, makes current more swimmingly through whole media bed 101.Impact can be increased to the water level in the reactor drum and be higher than groove 108.Can resemble and handle the processing of flush discharge and be collected in the impact draining in the groove 108.Remove TSS thus and can reduce or eliminate demand above-mentioned strict flushing.Perhaps, can be recycled to lower port 102 from some or all of ballistic drainings.Although maybe solid matter be placed reactor drum 100 other positions of not expecting thus, impingement flow is little and can in above-mentioned abundant flushing, remove the recirculated solids material.In addition, a part of solid matter that impacts in the draining is biodegradable.Solid matter is carried out recycling can make their biological degradations, thus the total amount of the mud that minimizing need be removed from total system.Required frequency of impact is relevant with the removal of gas or solid matter with the time length, thereby relevant or all relevant with the two with suspended sediment concentration or nitrogen concentration in reactor drum 100 inlets.

With reference to figure 9, shown another system 200 that is used to handle feed 202, said feed 202 can be the FGD sewer.In first pre-processing device 204, and randomly in second pre-processing device 206 or more pre-treatment step in, feed 202 is carried out pre-treatment.These equipment 204,206 for example can be physics or chemistry or physics and chemical treatment step, and for example built-up type mixing tank and settler are used for any pre-treatment step that lime for example or sulfide precipitation or the application describe.Pre-treatment draining 208 flow to two stage biological reactor drum 210, and said reactor drum 210 has the reactor drum shown in Figure 4 100 of the downflow system operation of two polyphones.Pre-treatment draining 206 flow to the port 106 of first reactor drum 100, flow to the port 106 of second reactor drum then from the lower port 102 of first reactor drum 100, and flows out the lower port 102 of second reactor drum.The treated draining 212 of leaving second reactor drum 100 can randomly flow to aerobic finishing apparatus 214, thereby produces final draining 216.Can flow to the backwash port one of reactor drum 100 03 from backwash feed chute 218 through making backwash water, reactor drum 218 is washed or impacts.Can backwash solid-liquid separating equipment 220 like pond or settler in, handle to be collected in impact or the wash-down water in the groove 108.Clarifying backwash water can be back to the device front portion.Can whole mud be transported to common sludge treatment system 224, perhaps can backwash water mud be transported to independent toxicity sludge treating system 226.Can add to nutritive substance in the pretreated waste water 208, in the pipe between first reactor drum, 100 lower port 102 and second reactor drum, 100 port 106, perhaps in the two.

The mikrobe of realizing above-mentioned various functions needs food or carbon source.Can use molasses class nutritional blend.Can select nutritive substance, when mixing with feed, for example be 100: 10: 1 carbon to provide: nitrogen: the ratio (CNP) of phosphorus.For example, feed possibly contain competent phosphorus, thereby in nutritive medium, can not need phosphorus.Can be for example per the speed of 1000 gallons of feedwater 0.2-0.4 gallon nutritive substances, supply with nutritive substance.Can in this basic mixture, replenish and add the trace nutrient and other composition that promotes target microorganism crowd stable growth.Can with nutritive substance add in secondary or the staged reactor preceding bio-reactor and/or second or post-reactor in.

If in the FGD system, use DBA to promote desulfurization, in waste water, will leave certain density DBA so.After physics or Chemical Pretreatment, even in a way after the aerobic bioreactor treatment step, a part or all DBA will remain in the waste water.DBA is that carbon class material and mikrobe can use it as nutritive substance.As shown in Figure 7, the DBA of capacity can be used as the also sole carbon source of pathogenic microorganism of selenium.More a spot of DBA can cause nutrition carbon amount or feed speed to descend.If excessive DBA suppresses required organic growth (comparing with unwanted organism) or hinders the control of ORP gradient, can reduce excessive DBA through before reactor drum 100, carrying out oxidation so.Usually, spendable DBA amount in anaerobic that can be through control of redox or nutritive substance or process upstream control bed or the anaerobism part.

When using reactor drum 100 that the first and second

anaerobic districts

24,26 and anaerobic zone 28 are provided, existence can occur in three main biochemical reactions in the bio-matrix.

The residual nitric acid root is reduced to nitrogen, discharges into the atmosphere then.

Selenium is reduced to simple substance form from oxidation state.Simple substance selenium forms so-called " nanometer ball ", and said nanometer ball will be attached on the microbial cell wall of realizing restoring function.Because microorganic adhesion is on medium, thus selenium also will be retained in media bed in until washing.

Existing sulfate radical is reduced to hydrogen sulfide.In addition, in the bio-matrix mixture, produce the sulfide that remains with the metallic sulfide deposition.Sulfide is compound with zinc, copper, nickel, lead and many other virgin metals effectively.Although can in the main processing step, realize required metal removal, reactor drum 100 can provide further processing and precision work (polishing) is provided for metal removal.

The formation of bio-reactor can comprise two or more reactor drums 100 of multiple row polyphone or other configuration.When waste water flows through two or morely during in abutting connection with each row that reactor drum 100 forms, can keep the plug flow state usually.This configuration can be convenient to control with above-mentioned three biochemical reactions or other reaction in each relevant redox-potential scope.Also can use and control similarly single bio-reactor 100.

Although above-mentioned each reaction as shown in Figure 8 possibly have eclipsed redox scope, said each reaction mainly takes place with different oxidation reduction scope.The waste water that gets into the preceding reactor drum 100 in each row just has or little negative redox potential.Along with flow flows through bed, redox potential reduces gradually.When redox potential falls into negative territory, will at first reduce the residual nitric acid root.Can know by Fig. 8, be low to moderate at current potential-nitrate radical will be reduced during 150mV.

Then when redox potential drop to-selenium will be reduced during 200mV.Be low to moderate at last ,-sulfate radical is reduced to sulfide during 300mV.Although sulfate radical reduction and selenium reductive ORP scope are significantly overlapping, the sulfate radical reduction can at first take place and have precedence in the selenium reduction, thereby possibly not reach the sulfate radical reduction of height or after the selenium reduction is close to fully, just can realize sulfate radical reduction completely.

Under the situation that is substantially the plug flow state, form the redox gradient along one or more.Can add speed or hydraulic pressure hold-time (HRT) or regulate both simultaneously through the nutritive substance of regulating in one or more beds, control this gradient.Usually, the size that can be through changing bed or the quantity of polyphone or parallel connection bed are selected the size of bed according to feed, change HRT in the design phase.HRT in one or more polyphone beds can be for example 2 hours～12 hours.After setting up system, the variation of reaction bed feeding flow velocity will change HRT.Yet after system set up and moves, nutrition is added possibly be easier to change.Nutrition adds that the polyoxy reduction potential is low more more; Reducing the nutrition interpolation will make redox potential rise.Optional inter-stage nutrition interpolation between the tandem reactors 100 can be redox control provides extra handiness.The ORP transmitter can be arranged on two reactor drum 100 exits separately in the level two.The ORP transmitter also can be arranged in the feed of reactor drum 100.The ORP transmitter also can be arranged on the intermediate point place in one or more levels of reactor drum.Operator or automatic system can be certain sampling interval record ORP value and preservation records of values.Said ORP value can be used for confirming the input parameter of unit or decision table.For example, sampling rate that can be certain (can change), the ORP value in the outlet separately of record second reactor two-stage between every day for example 1 to 24 time.Calculate the ORP in 0.5～2 day operation MV (running average) for example of average period.Utilization and operation MV also manually or automatically confirms how to change the final stage nutrition supply in arbitrary level or the two-stage, to produce the more redox potential of expectation.

Since can the controlled oxidation reduction potential, so can adjust so that the removal of some pollutent reaches optimizing to system.Particularly, may command nutrition is added, thereby the selenium reduction-oxidation reduction potential that maintenance is best at least one section of reactor drum (50～-200mV).For example, can calculate the nutrition at first reactor drum, 100 upper reaches in the level two and add, with produce-50 at first reactor exit～-ORP of 200mV.The nutrition at may command second reactor drum 100 upper reaches is added, with in the outlet of second reactor drum 100, produce-200～-ORP of 350mV, thereby increase the sulfide that produces in second reactor drum 100.As replaceability embodiment; The metal of in reactor drum, removing is not too under the important use; May command nutrition is added; With the exit generation-50mV of level two first reactor drum 100 or for example following-50mV～-ORP of 100mV, and the exit generation-200mV of level two second reactor drum 100 or for example above-150mV～-ORP of 200mV.

Be substantially the plug flow state and allow particular cluster to reside in some exclusive districts in the carbon bed, thereby multiple organism can be contained in each district, but the redox potential of each function maybe be overlapping.However, still can realize the removal of all contaminations.

In Fig. 5, verified of the influence of ORP gradient to pollutant removal.The water that gets into reactor drum 100 contains the oxidizing substance (being nitrate radical, selenate radical, selenite radical) of dissolved oxygen and pollutent, and has in this embodiment+the positive ORP of 100mV.Different position collected specimens in the multi-stage biological reactor drum, and measure ORP, selenium, sulfate radical and nitrate radical-N.Along the ORP gradient of in the bio-reactor bed, having set up, pollutent was removed in their stages separately.

Can be through the conveying inter-stage nutritive substance HRT at different levels (realizing), via the control ORP of system through improving or reduce the injection flow velocity with control.Can ORP be controlled at+150mV is to the scope of-400mV.

In the embodiment of Fig. 5, reactor drum is divided into six grades.In the first step, remove nitrate radical-N, only have simultaneously 25% selenium to be reduced.Sulfate radical is not reduced.Removal at different levels afterwards is as shown in the figure.Through control ORP gradient,, can make system for example only remove nitrate radical-N, remove nitrate radical-N and selenium and/or remove multiple pollutent through directly reducing and sulfide precipitation.

Denitration can be carried out with sulfate radical and selenium reduction or before sulfate radical and selenium reduction, carry out simultaneously.The formation of nitrogen is fixed on the mounting medium (will be retained in the system) owing to carry out the biomass of these reactions, so can not influence the reservation of biomass in essence.Can remove the gas that forms in the reactor drum as required through aforesaid impact.

The biomass that in the bio-reactor unit, grow exist in environment naturally.But sulfate radical reductive agent and denitrfying agent self-sow need not to encourage.Suppose and in main treatment step, to accomplish required metal removal that randomly, the may command redox potential makes sulfate radical reduction (forming with sulfide) minimize.

For example the Applied Biosciences Corp. of Utah, USA can separate the mikrobe that selenium oxide is reduced to simple substance form from the different zones of Western United States.Separable and several species of cultivating in these mikrobes.During the device starting, microbial inoculant charging (innoculumcharge) can be provided, bed is inoculated.For example, mikrobe initial charge capable of using is inoculated bio-reactor 100.Initial charge can comprise the 2-6 pseudomonas and belong to (Pseudomonas), Shiva Bordetella (Shewanella), the mikrobe of Alkaligenes (Alcaligenes) or the mixture of other environmental microorganism; According to or expection microbial growth and the water paid close attention in the pollutent reduction, said mikrobe is selected.Can through elsewhere preparation before providing through spinning and cryodesiccated Initial microorganisms, cultivate enough big micropopulation on the spot so that reactor drum 100 is inoculated.These mikrobes are rapidly attached on gac or other medium, after this breed existing under the situation of nutritive substance.Add after the inoculum, the bio-reactor unit can move several days to allow microorganic adhesion by circulation pattern.The replaceability inoculating process at first is immersed in bed in the nutrient solution.Through after this pre-treatment, the microbe inoculation mixture (randomly comprising some nutrient solutions) in the water of a reaction tolerance is put into reactor drum.Then reactor drum was left standstill for some time as 1 to 3 day, with allow mikrobe incoming flow begin through before the reactor drum attached to medium on.After this, can introduce standard feed stream and also can carry out the device trial run.

Trial run can be carried out periodic biological assay evaluation after finishing.Carbon appearance is gathered at the different depths place that this evaluation can be included in each bio-reactor unit.Can measure the redox potential of each sample and examined mikrobe, to set up coenosis collection of illustrative plates (biological community profile).This research can produce the information baseline, mixes to guarantee the mikrobe that keeps suitable in the system as time goes by, and under the situation that control nutrition is added, for example can consider and online ORP measures combination or regulates target ORP scope.

After the device trial run, can carry out two or more biological assay evaluations.When the live body characterization and evaluation shows that the required specified microorganisms of selenium reduction does not exist with suitable number, can replenish and add the inoculation charging.Can carry out other live body characterization and evaluation every now and then, with the operation of monitoring reaction device, result of study is to improve the required ORP scope in a place or many places in the reactor drum.Can use above-mentioned reactor drum that one or more in the first and second

anaerobic districts

24,26 and the anaerobic zone 28 are provided.

Fig. 3 shows the aerobic district 22 be used to provide shown in Figure 1 and the nitrated/Benitration reactor 80 in the first anaerobic district 24.Nitrated/Benitration reactor 80 also can be used for replacing biological respinse tank and the ZeeWeed groove of Fig. 2; So that the aerobic district 22 and the first anaerobic district 24 to be provided, and make the ABMet reactor drum to move under the situation in the first anaerobic district 24 having the second anaerobic district 26 and anaerobic zone 28 and have the first minimum anaerobic district 24 or do not have.

Claims

1. method of wastewater treatment, this method have the anaerobic treatment step useless stream being carried out denitration and anaerobic treatment step subsequently removing selenium,

One or more during this method is further comprising the steps of:

A) anaerobic digestion is with the stream membrane sepn that gives up before the removal selenium step;

B) dilute before the digestion step; Or

C) carry out the physical/chemical pre-treatment before digestion step or the dilution step and flow to remove also softening the giving up of TSS,

Wherein before the anaerobic treatment step of denitration the ORP of useless stream remain on+100mV to 0mV between, the useless ORP that flows remains on below the 0mV after the anaerobic treatment step of removing selenium.

2. the method for claim 1, this method comprise that also the anaerobic treatment step is to remove heavy metal.

3. the method for claim 1, this method comprise that also the aerobic treatment step is to remove COD or to carry out nitrated to said useless stream before the step of claim 1.

4. the method for claim 2, this method comprise that also the aerobic treatment step is to remove COD or to carry out nitrated to said useless stream before the step of claim 1.

5. each method in the aforementioned claim, the useless stream of wherein discharging has-50mV or following ORP.

6. the method for claim 5 wherein through the position or the speed of control feeding nutritive substance, keeps ORP.

7. each method in the claim 1 to 4 when this method also is included in the interpolation speed of confirming the carbon nutrition material, is calculated the DBA (diprotic acid) that exists in the useless stream.

8. each method in the claim 1 to 4, wherein the anaerobic treatment step carries out in fixed-film biological reactor.

9. the method for claim 1, this method comprise that also the anaerobic treatment step is to remove arsenic, mercury or sulphur.