DE102004030482B4 - Process for the treatment of waste water from the treatment and treatment of organic waste, in particular manure, with a biogas fermenter - Google Patents

Abstract

method for the treatment of waste water from the processing and treatment of organic waste, in particular of manure, with a biogas fermenter (2) with subsequent ultrafiltration (7) and Reverse osmosis (10, 11), characterized in that a at the ultrafiltration (7) separated suspended waste into the biogas fermenter (2) is returned.

Description

The The invention relates to a process for the treatment of effluents the processing and treatment of organic waste, in particular of manure, with a biogas fermenter, followed by ultrafiltration and Reverse osmosis.

In huge Areas of Germany is an intensive livestock farming. In order to connected are corresponding manure quantities, as organofluid fertilizers so far were applied alone in the surrounding agricultural area. Manure has dissolved in the water phase in addition to the salts a considerable portion of ammonium nitrogen, the Of soil bacteria relatively quickly converted into nitrate and thus for the plants as a nitrogen source is directly usable. Will the slurry offer but too big Thus, a portion of the nitrate passes into deeper soil layers up into the groundwater. Thereby can Groundwater contaminants occur, so that the annual slurry contract per hectare legally was limited. Even against this background have in the past developed various methods for biogas production.

On the one hand this is a biogas production based on organic waste the food industry, from the food trade and from the Gastronomy, without and with manure insert. Can in the organic waste Remains of animal origin, leftovers, etc. not one hundred percent must be excluded, so this must Part at least pasteurized before a fermenter feed, for Part to be sterilized.

The strongest at the moment Spread has the biogas production on the basis of manure and renewable vegetable raw materials, with only the Manure then must be pasteurized, if in the manure catchment area Animal diseases threaten or already exist.

A Another type of biogas production is municipal biogas production by preferred use of sewage sludge wastewater treatment mixed with ground biowaste and others Substances.

A method of the type mentioned is, for example, from DE 196 13 397 C2 known. The method described there shows a method for the biological purification of wastewater with two fermentors connected in series, wherein each fermenter is followed by a cell restraint system.

Of the Invention is based on the object, a method for processing of wastewater from the processing and treatment of organic waste, in particular of manure, with a biogas fermenter with subsequent ultrafiltration and / or To create reverse osmosis, in which a reprocessing of organic waste especially of manure, can be particularly effective.

The solution This object is achieved by a method with the features of Patent claim 1. Advantageous developments of the invention are in the subclaims described.

at a process for the treatment of wastewater from the treatment and Treatment of organic waste, especially of manure, with a biogas fermenter with subsequent ultrafiltration and / or Reverse osmosis, it is essential to the invention that a in the ultrafiltration separated Schwebtrub is returned to the biogas fermenter. With this hovering tribe Anaerobic methanobacteria are returned to the biogas fermenter, causing the biogas production per unit time is increased accordingly.

Prefers the levitation trub is fed directly into the biogas fermenter, ie without any detours via other systems recycled. there is the procedure in biogas fermenter and subsequent steps up including the ultrafiltration preferably anaerobic. This means that no oxygen is supplied, So that the Methanobacteria can remain active and not inactivated by oxygen. In a preferred Development of the invention are taken from the biogas fermenter Substances of at least two consecutive mechanical separation processes subjected, one of them, especially the second. as ultrafiltration with return of the separated Schwebtrubs is performed. The first separation process is preferably a solid-liquid separation. This can in particular also with a decanter or with a in the effect equivalent device combination respectively.

In A preferred embodiment of the invention is the wastewater acidified after ultrafiltration and before performing reverse osmosis. The pH is after the ultrafiltration in the order of 8. By acidification is achieved that at the existing high ammonium content prevents ammonia formation becomes.

In another preferred development of the invention, material is taken from the biogas fermenter in at least two different ways. In this case, the biogas fermenter is preferably taken from a digestate template, which in turn is separated with a solid-liquid separation.

The liquid removed from the fermenter, in particular the fermenter residue sample taken from the fermenter, which is replaced by a Solid-liquid separation separated is, and in particular a so-called turbidity, with a flocculant added. The turbidity process is preferably an intermediate container with stirrer supplied in which also the biological flocculant, preferably corn silage, is given. The flocculant approach thus produced is returned to the Solid-liquid separation led and separated again. Thus, a double passage is preferred the solid-liquid separation, in particular a decanter or equivalent in effect Device combination, carried out. At the first pass through the solid-liquid separation is the discharged Material that consists of a ausgegorenen solids discharge, as Compost used. The material contains about 73% product water, can be stored in rents and forms a loose, pour and spreadable Compost. The liquid content the first run is in an intermediate tank with agitator with the biological Flocculant, in particular maize silage, applied. On the liquid About 10% to 12% flocculant is added. This homogeneous Approach is in the solid-liquid separation returned and the Solid fraction, which in turn is fermentable by the added flocculant, returned to the fermenter. The Flocculant is thereby together with the adhering bacterial fine stubborn returned to the fermenter as a complete fermentation material. The liquid content the second pass is supplied to the ultrafiltration, whereby this is charged much less.

Of the in solid-liquid separation in the first pass separated solid part is preferably under use the process heat pasteurized and processed into a dispersible organo fertilizer. Furthermore becomes the biogas fermenter taken a drain material. The process becomes a solid-liquid separation supplied and the solid components are recycled in the biogas fermenter. Thereby there is also the possibility the biogas fermenter additional Supply adjusting water, whereby the pollutant concentration for the bacteria in the fermenter, in particular a high ammonium nitrogen content can be lowered can. The liquid ones Shares of the biogas fermenter taken in different ways Materials are in a preferred embodiment of the invention together and the ultrafiltration supplied.

In Another embodiment of the invention are those of ultrafiltration supplied liquids passed through a magnetic field. The liquids still contain a relatively high calcium content, which typically lime precipitation can form in the pipe system and litter this. Through the guide through the magnetic field this is prevented. Also a precipitate as calcium / magnesium carbonate on the membranes of ultrafiltration is through appropriate magnetic fields prevented in the piping system before ultrafiltration.

Preferably, a filtrate obtained in the ultrafiltration is then fed to a reverse osmosis. The reverse osmosis is preferably carried out in two stages. In this way, a particularly high purity is achieved. In this case, at least a portion of the filtrate of reverse osmosis, in particular the filtrate of a first stage of reverse osmosis, is preferably recycled as starting water into the pre-pit of the biogas fermenter. This saves water, which is needed for the overall process. Furthermore, in the 2-stage reverse osmosis in the second stage, only smaller amounts of einleitfähigem water to clean, and it can be done a correspondingly finer cleaning. In a preferred embodiment of the invention, the filtrate template for the reverse osmosis is acidified. For this purpose, sulfuric acid is preferably used for setting and stabilizing the ammonium nitrogen in the aqueous phase. The resulting ammonium sulfate can be isolated by reverse osmosis better than ammonium hydroxide. To reduce the ammonium nitrogen content as much as possible, a series of steps are carried out. In particular, the ultrafiltrate permeate provided for the first reverse osmosis stage is acidified very well in order to lower the ammonium nitrogen to at least pH <4 as a result of the pH reduction. Preference is given to reuse the sulfuric acid already used for drying the compost. The first stage of reverse osmosis provides a retentate which is more highly concentrated than the ultrafiltration permeate and which can now be completely acidified stoichiometrically. This produces an ammonium-bound, phosphate-depleted mineral concentrate, which can be used as a highly concentrated liquid fertilizer. The permeate of the first reverse osmosis or the first stage of the reverse osmosis is preferably also stoichiometrically acidified to bind the free ammonium. The ammonium nitrogen is bound via the acidification as a salt, so that the second reverse osmosis provides a permeate, which provides less than 10 g of ammonium nitrogen / m ³ and thus directly einleitfähiges water. The retentate of the second reverse osmosis is preferably returned to the filtrate template of the reverse osmosis and again passes through the two-stage reverse osmosis.

In another preferred development of the invention, the acid is supplied, in particular in each case the stoichiometric acidification of Re tentats the first stage of reverse osmosis and permeate the first stage of reverse osmosis, with simultaneous oxygen supply and turbulence and pressurization of the components to be mixed, preferably a pressure of 5 bar to 8 bar is applied. In this step, over- and under-pressure conditions are built up within a mixing container and the retentate or permeate is entangled with the added acid and then forcibly supplied ambient air and in particular oxygen. In this way many organic compounds can be oxidized and bacteria and germs can be killed. The reverse osmosis retentate is preferably further processed using process waste heat to form a spreadable phosphate-depleted ammonium sulfate potassium chloride fertilizer. In another preferred development of the invention, the water end filtrate of the reverse osmosis is supplied with ozone or with chlorine dioxide. As a result, possibly remaining bacteria and viruses are killed, remaining odors oxidized and it is created the opportunity to make the water into natural waters einleitfähig.

following the invention is based on a preferred illustrated in the drawing embodiment further explained. The schematic representations show in detail in:

1 : a schematic sequence of the method according to the invention and

2 : the schematic sequence of an extended method according to the invention.

The method is particularly suitable for slurry processing. Manure or other organic waste and renewable raw materials, such as corn silage, are first placed in a pre-pit 1 introduced and from there with a pumping system in a fermenter or biogas digester 2 brought in. The biogas fermenter 2 is continuously a ausgegorene digestate template 3 taken from a first solid-liquid separation 4 is supplied. The drainage material from this solid-liquid separation 4 forms an organic residue, which in the figure at the arrow 21 arises. This Organorückstand is already so dry that it can be transported by belt conveyor. This can be left so or by means of the schematically with 13 indicated system waste heat to be dried and packaged loose or packaged goods with the addition of special mineral fertilizer or by adding the self-fertilizer described below. Thus, an organic fertilizer is available as a primary fertilizer. In terms of volume is about 10% of the biogas fermenter 2 supplied amount as organic fertilizer 21 won. The liquid fraction of solid-liquid separation 4 serves as a filtrate template for ultrafiltration 6 , Next will be from the biogas fermenter 2 taken directly high fermentable material and in a second solid-liquid separation 5 dehydrated and as a concentrate in the biogas fermenter 2 returned. This is by the arrow 22 indicated. The solid-liquid separation 5 supplied material is over 50% according to the arrow 22 back to the biogas fermenter 2 recycled. This process step serves the additional removal of ammonium nitrogen and potassium via the discharged water phase. This makes the carbon-nitrogen ratio in the biogas fermenter 2 Improves and increases together with the concentrated fermentation substrate, the biogas yield per unit time. The filtrates of solid-liquid separation 4 and solid-liquid separation 5 are used in ultrafiltration as a filtrate template 6 collected. With ultrafiltration 7 is the entire fermentable fine particle stock including from the biogas fermenter 2 discharged methanobacteria from the filtrate and as a retentate, according to the arrow 23 , in the biogas fermenter 2 recycled. This not only biogas-producing material, but also the Methanobakterien- Lebendbesatz is significantly increased. This in turn increases the biogas yield per unit of time. It is procedurally ensured that the oxygen uptake in the aqueous material remains so low that the methanobacteria are not damaged. In ultrafiltration 7 arise retentate and permeate about equal parts, the permeate then the reverse osmosis filtrate 8th wherein it is used to stabilize the ammonium component by adding acidic components 9 is acidified accordingly.

In the following reverse osmosis are preferably two stages, namely once a first reverse osmosis 10 and a second reverse osmosis 11 carried out. These are designed so that of the discharged retentate 24 about 95% of reverse osmosis 10 come from and only about 5% of reverse osmosis 11 , This retentate 24 provides the actual ammonium potassium component. For this purpose, the retentate is re-acidified stoichiometrically, so that the ammonium is present in non-volatile salt form. The resulting materials are in a treatment and drying plant 14 using the excess heat 13 of the biogas fermenter 2 evaporated to dryness. The resulting condensate is preferred over the reverse osmosis 11 passed and cleaned and can then also after an ozonation 12 be derived. After performing the first stage of reverse osmosis 10 becomes the second stage permeate of reverse osmosis 11 supplied, wherein previously according to the arrow 25 prefers almost half of the first stage of reverse osmosis 10 purified Water as preparation water in the pre-pit 1 is branched off. The following reverse osmosis 11 Removes the remaining permeate, especially with regard to residual ammonium on the full discharge and thus provides a water 26 that can be used in the agricultural sector. If necessary, an ozonation takes place 12 with the water 26 germ-free and virus-free can be made.

In 2 an expanded or modified version of the method according to the invention is shown. The same steps are identified by the same reference numerals, and it is in this respect to the description of 1 Referenced. From the pre-pit 1 Here, too, the liquid manure is transferred to the fermenter 2 introduced, and the fermenter or biogas digester 2 becomes a digestate template 3 taken. This becomes a solid-liquid separation 4 supplied, which predominantly comprises a decanter or equivalent in effect device combination. In the embodiment of the invention shown here, the ausgegorene solid discharge of the solid-liquid separation 4 according to the arrow 21 taken and used as compost. The result is a loose, pourable and scatterable compost discharge with a water content of about 73%. This is dried before a rents storage, which also takes place a Wrasenführung sulfuric acid for drying. The sulfuric acid used here can be used later for pre-acidification of a filtrate template of reverse osmosis. This compost is the first end product of the process according to the invention. The liquid content of the solid-liquid separation 4 , which is also referred to as turbidity, is according to the arrow 41 in an intermediate container with agitator 40 guided. In these also a biological flocculant according to the arrow 44 guided. For this maize silage is preferably used. The resulting flocculant approach is according to the arrow 42 for a second pass in the solid-liquid separation 4 guided. During the second pass, the solid fraction is fermentable solids discharge according to the arrow 43 in the fermenter 2 recycled. In this case, the flock agent adhering bacteria fine trash is also returned to the fermenter, so that in this way the fermentation process is supported. The at this second stage of solid-liquid separation 4 separated liquid part, which is also referred to as a clear flow is, according to the arrow 45 the ultrafiltration filtrate template 6 fed. The corresponding pipe system is surrounded by permanent magnets, so that a magnetic field is formed which prevents or at least greatly reduces the typical lime precipitation. The ultrafiltration filtrate is then fed to the ultrafiltration, where the tubes are also surrounded by magnets or a magnetic field is formed in the tubes in order to reduce lime precipitation there and also to prevent calcium / magnesium carbonate from precipitating on the ultrafiltration membranes and these be blocked by it. In ultrafiltration, the entire, still fermentable fine particle stock including the discharged methanobacteria is isolated and according to the arrow 23 returned to the fermenter. In the fermenter 2 Thus, the retentate of ultrafiltration as well as the fermentable solids discharge of the solid-liquid separation 4 recycled. The permeate of ultrafiltration 7 is fed into the filtrate template of reverse osmosis. Here is a Vorsäuerung 9 or a thorough acidification by means already used in the acid scrubber sulfuric acid from the compost drying process. The filtrate template 8th becomes the first reverse osmosis 10 or the first stage of reverse osmosis 10 fed. The retentate is in the step 30 tested for free ammonium and stoichiometrically bound with H ₂ SO ₄ . In this case, the sulfuric acid is fed to the retentate in a mixing process conducted under special pressure conditions, a very thorough mixing taking place. In addition to a targeted excess of acid and by absorbing air remaining odors are hydrolyzed in the concentrate and oxidized. This first-stage reverse osmosis retentate is the second end product. The result is an ammonium-bound, phosphate-depleted potassium-rich mineral concentrate in the form of a highly concentrated liquid fertilizer. This can be stored in a tank storage. The permeate of the first reverse osmosis 10 is in the step 31 post-processed and still free ammonium is bound by means of sulfuric acid. Acidification is possible and appears in the retentate of the second stage of reverse osmosis 11 , The acid entry is preferably carried out again with a pressure-guided process with strong mechanical mixing. The thus retreated permeate the first reverse osmosis 10 then becomes the second reverse osmosis 11 fed. The retentate of the second reverse osmosis 11 becomes according to the arrow 32 for concentration in the filtrate template of reverse osmosis 8th recycled. The reverse osmosis second stage permeate is a feed water that forms the third end product of the process. This water will be in the pH below 5 and must therefore be passed over dolomite rock or limestone for neutralization. In order to prevent fouling of the reverse osmosis membrane, a short burst of sulfuric acid (approx. 20% - H ₂ SO ₄ ) is passed once a day. The method so far described is considered the primary method. In the secondary method is the primary method at the arrow 21 dried compost dried. This happens in the fluidized bed or vibratory dryer. The moist air, laden with odorous substances and ammonia, is passed through sulfuric acid, which binds the corresponding substances. This sulfuric acid can then be used in the pre-acidification step 9 to be used again. The compost can also with different amounts of concentrate, the ent speaking the arrow 24 as a result of stoichiometric acidification 30 is recovered, charged and dried. This results in a fully operational fertilizer compost product as a primary or multi-component fertilizer.

Claims (25)

Process for the treatment of waste water from the treatment and treatment of organic waste, in particular manure, with a biogas fermenter ( 2 ) followed by ultrafiltration ( 7 ) and reverse osmosis ( 10 . 11 ), characterized in that a in the ultrafiltration ( 7 ) Separated levitation trub into the biogas fermenter ( 2 ) is returned. Process according to claim 1, characterized in that in the ultrafiltration ( 7 ) separated levy trub directly into the biogas fermenter ( 2 ) is returned. Method according to one of claims 1 or 2, characterized in that the method in Biogasfermenter ( 2 ) and subsequent steps up to and including ultrafiltration ( 7 ) is carried out anaerobically. Method according to one of the preceding claims, characterized in that the biogas fermenter ( 2 ) is fed to at least two consecutive mechanical separation processes, one of which, in particular the second mechanical separation process, being used as ultrafiltration ( 7 ) is carried out with recycling of the separated levitation trub. Method according to one of the preceding claims, characterized in that the biogas fermenter ( 2 ) is taken from at least two different procedures material. Method according to one of the preceding claims, characterized in that the biogas fermenter ( 2 ) a digestate template ( 3 ), which are treated with a solid-liquid separation ( 4 ) is separated. Process according to claim 6, characterized in that a liquid part of the solid-liquid separation ( 4 ), in particular the turbid flow, is mixed with a flocculant and passed back into the solid-liquid separation. Method according to one of claims 6 or 7, characterized in that the solids discharge of the solid-liquid separation ( 4 ), as far as it is fermentable, in the biogas fermenter ( 2 ) is returned. Method according to one of claims 6 or 7, characterized in that the separated solid part using the process waste heat ( 13 ) is pasteurized and processed into a dispersible organo fertilizer. Method according to one of claims 1 to 9, characterized in that from the biogas fermenter ( 2 ) Material is removed via a drain. Process according to Claim 10, characterized in that the course of a solid-liquid separation ( 5 ) and the solid components in the biogas fermenter ( 2 ) are returned. Method according to one of the preceding claims, characterized in that the liquid portions of the biogas fermenter ( 2 ) and the ultrafiltration ( 7 ). Method according to one of the preceding claims, characterized characterized in that fed to the ultrafiltration liquid passed through a magnetic field becomes. Method according to one of the preceding claims, characterized in that in ultrafiltration ( 7 ) recovered filtrate of a reverse osmosis ( 10 . 11 ) is supplied. Process according to Claim 14, characterized in that the reverse osmosis ( 10 . 11 ) Is carried out in two stages. Process according to one of claims 14 or 15, characterized in that at least part of the filtrate is reverse osmosis ( 10 ), in particular a part of the permeate of a first stage of reverse osmosis, as a starting water in the Vorgrube ( 1 ) is returned. Process according to one of Claims 14 to 16, characterized in that the filtrate ( 8th ) is acidified for the reverse osmosis. Process according to claim 17, characterized in that for the acidification of the filtrate ( 8th ) is fed from a parallel running compost drying process used sulfuric acid. Process according to one of claims 14 to 18, characterized in that the retentate of a first reverse osmosis ( 10 ) is tested for free ammonium and ligated stoichiometrically with the addition of acid. Process according to one of claims 14 to 19, characterized in that the permeate of first reverse osmosis ( 10 ) is stoichiometrically acidified to bind the free ammonium. Method according to one of claims 14 to 20, characterized in that a retentate of the second reverse osmosis ( 11 ) in the filtrate template ( 8th ) the reverse osmosis is returned. Method according to one of claims 14 to 21, characterized that the Acid intake under simultaneous oxygen supply and turbulence and pressurization the components to be mixed takes place. Method according to one of the preceding claims, characterized in that the retentate of reverse osmosis ( 10 . 11 ) using process waste heat ( 13 ) is processed into a spreadable phosphate-depleted ammonium sulfate potassium chloride fertilizer. Method according to one of the preceding claims, characterized characterized in that Permeate the reverse osmosis with ozone or with chlorine dioxide becomes. Apparatus for carrying out the method according to one of the preceding claims.