DE102008002812A1 - Process for the treatment of domestic waste water generated in households - Google Patents

Abstract

The invention relates to a process for the treatment of domestic sewage accumulating in households, which is conveyed by means of a vacuum sewage system and then treated anaerobically and / or aerobically. In order to make full use of the regenerative energy potential in the waste water and the biomass produced in the wastewater treatment, it is proposed that domestic wastewater be enriched with organic substances in order to then supply this by means of negative pressure to a collecting tank. This is followed by an aerobic pre-treatment in a first reactor in which a 3-phase separation takes place in that a separate removal of biogas, anaerobically pretreated wastewater and incompletely digested sludge takes place.

Description

The The invention relates to a method for processing in Domestic wastewater generated by household promoted a vacuum sewage system and then anaerobically and / or is treated aerobically.

One Vacuum wastewater system, d. H. the so-called vacuum sewerage or vacuum drainage not only provides solutions for technical and topographical problems, but also offers the advantage that the accumulation of wastewater in comparison is reduced to the conventional free fall channeling. The by means of the prevailing in the vacuum sewer vacuum subsidized wastewater is a collection container supplied, from which the wastewater of a conventional Clarification is supplied, which also for the free fall channelisation is used. there is basically the regenerative energy potential in Wastewater and not fully utilized in the resulting biomass.

From the DE-A-10 2005 063 228 For example, a process for purifying wastewater having an anaerobic biological treatment step is known, wherein the anaerobic biological purification is carried out by means of biomass selected from psychrophilic microorganisms. In this case, sewage and kitchen waste are fed by vacuum sewerage in practice anaerobic cleaning.

One Disposal concept for Shanghai, China is, that brown and black water along with kitchen waste is fed by means of vacuum sewer to a digester, resulting biogas for the production of electrical energy or heat used and the sludge removed in the digester is used as fertilizer.

The the state of the art to be taken disposal concepts under However, incorporating a vacuum sewer system does not fully exploit that Energy potential in wastewater and biomass.

Of the The present invention is based on the object, a method of the aforementioned type so that the regenerative Energy potential in wastewater and wastewater treatment biomass is fully utilized. There is a desire to carry out an energy self-sufficient disposal.

• – Anreichern des häuslichen Abwassers mit organischen Stoffen und Transport des angereicherten Abwassers in einen Sammelbehälter mittels des Unterdruckabwassersystems,
• – anaerobes Vorbehandeln des angereicherten häuslichen Abwassers in einem ersten Reaktor,
• – getrenntes Abführen aus dem ersten Reaktor von durch die Vorbehandlung entstehendem Biogas, anaerob vorbehandeltem Abwasser und unvollständig gefaultem Schlamm,
• – wobei aus dem Biogas Energie gewonnen wird, das anaerob vorbehandelte Abwasser aerob-biologisch nachbehandelt wird und der unvollständig gefaulte Schlamm in einem zweiten Reaktor anaerob-biologisch behandelt wird.

According to the invention, the method is essentially achieved by the method steps

• - enriching the domestic wastewater with organic matter and transport of the enriched waste water into a collecting tank by means of the vacuum sewage system,
• Anaerobic pretreatment of the enriched domestic waste water in a first reactor,
• Separate removal from the first reactor of biogas produced by the pretreatment, anaerobically pretreated waste water and incompletely digested sludge,
• - Wherein energy is extracted from the biogas, the anaerobically treated wastewater is aftertreated aerobically-biologically and the incompletely fouled sludge is anaerobically-biologically treated in a second reactor.

there In particular, it provides that the domestic sewage fed to the first reactor with the exclusion of rainwater becomes.

According to the invention proposed a supply plan that covered the budget incurred Media almost completely uses water and food, so that forms an energy self-sufficient system in which the regenerative Energy potential in domestic wastewater is fully utilized. Emission or residues are avoided. there can according to the embodiments of the invention Teaching growing biomass to be used in addition. The same applies to rainwater, which is collected and managed in such a way will be kept away from the first and second reactor, So the biological purification of domestic sewage in the first two reactors are not affected, but also can be treated.

essential Characteristic is the 3-phase separation in the first reactor, in which the domestic wastewater is anaerobically treated biologically. The disposal concept also offers the possibility that the treated wastewater flows through irrigation or infiltration supplied to the natural water cycle so that the treatment effort to clean the respective wastewater flow based on its degree of contamination. The environmental impact is due to an almost zero emission maximized. Hygiene risks are excluded if a direct Reuse of the purified wastewater is omitted.

To enrich domestic wastewater with organic components, kitchen waste is added to household gray and black water. For this purpose, the kitchen waste is previously crushed as shredded with a crusher installed in a drain. The wastewater is transported together with the kitchen waste in a service connection shaft and then in the sump of the vacuum sewer system by negative pressure. Through the use of vacuum sewage system and thus the installation of vacuum toilets in the home are recognizable the Drinking water required for toilet flushing and the corresponding amount of wastewater significantly reduced. Values of about 25% can be assumed.

At the vacuum system, the downpipes are not connected, so that only domestic wastewater is used, this compared to the usual gradient channeling reduced in volume and also in terms of organic Cargo is enriched by the kitchen waste.

consequently increase the concentrations of dissolved and solid organic ingredients in domestic wastewater, d. h., that wastewater compared to conventional domestic Wastewater is highly enriched with organic matter.

The Domestic sewage is by means of vacuum sewerage collected and then to a specially designed wastewater treatment plant transported to the treatment of domestic sewage, where neither rain nor other extraneous water in the vacuum sewer reach. Thus, the domestic sewage experiences no dilution and stays compared to conventional Wastewater strongly enriched with organic matter.

The rainwater accumulating in settlements for roof and street drainage In contrast, it is collected separately and can be used in the usual way Rainwater storage are fed, then one Rainwater treatment, as described below is explained.

The Concentration of domestic sewage offers the possibility an anaerobic wastewater treatment, which in the first reactor - also anaerobic reactor called - performed with integrated 3-phase separation becomes. It should be the first reactor, a high-load reactor or at least one used, the residence time of less than 24 hours at degradation rates of 60% -80% of the organic Domestic sewage freight allows.

While anaerobic biological purification fall into the anaerobic reactor separately biogas, an anaerobically treated wastewater and a not complete Fouled sludge, according to the invention separately be treated further. Anaerobic processes form compared to aerobic activation processes very little biomass.

The Anaerobically pretreated wastewater is then a second biological Treatment applied to remaining biodegradable organic To remove substances. As a result, there is a high degree of elimination achievable. The second biological treatment is carried out with the help of a aerobic biocynosis. In particular, a contact biology method is involved provided in which the biomass immobilized on carriers is. Because of the anaerobic pretreatment is the oxygen demand and thus the energy consumption of the used ventilation fan comparatively low. As carrier material, a fixed bed, a fluidized bed or other regularly submerged Contactors are used.

In terms of regularly appearing contactors is the following noted. The bacteria are immobilized on carriers, which are moved mechanically. The mechanical movement of the carriers takes place for. B. by rotation, especially when discs or Drums can be used as a carrier of biomass. Therefore is often called the term "rotating Biokontaktor "or" Biorotor "used.

Integrated in and downstream of the contact biology method is a method for solids separation, such as biomass provided. Because the contact biology method comparatively small amounts of excess Biomass can be formed, microsieg, microfiltration or ultrafiltration are used for solids separation, wherein the separation from the requirements for the reuse of the purified wastewater and thus the associated risk of hygiene is. This corresponds to the method steps explained above anaerobic-biological, aerobic-biological and mechanically clarified Wastewater can then be used for irrigation, for example Become to the still contained nutrients of the vegetation supply.

The in the aerobic biological treatment or mechanical treatment resulting solids are then fed to the second reactor, in which an anaerobic biological treatment of the incomplete fouled sludge is withdrawn from the first reactor becomes.

by virtue of the combination of anaerobic pretreatment, aerobic aftertreatment with contact biology procedures where little excess Biomass grows up, the sludge production is compared greatly reduced to conventional activation processes.

If it is intended that the treated anaerobic biological treatment stage clarified wastewater is fed to the water management, z. B. with treated rainwater, the anaerobically treated wastewater must be subjected to another process step before the aerobic treatment, in which nitrogen and phosphorus is removed to prevent eutrophication of natural waters. The removal of nitrogen and phosphorus can be carried out biologically or chemically by precipitation. A failure of Nitrogen and phosphorus may, for. B. by means of the so-called MAP (magnesium ammonium phosphate) precipitation.

Of the incomplete in the 3-phase separation in the first reactor Rotten sludge becomes the second reactor anaerobic biological Sludge digestion supplied. In the second reactor will also the separated biomass initiated in the aerobic aftertreatment of anaerobically treated wastewater. Beside these Thin sludges can be used to further dry biomass other organic household waste, green waste or organic residues from agriculture to the second reactor be fed so that the merged organic waste thin sludge or biomass be rotted out in a co-fermentation. Depending on the ratio between fed sludge and fed dry Biomass results in a certain dry matter content for the sludge, which is supplied to the digestion. The dry matter content should be above 50 g / l. Consequently, sludge may need to be preceded thickened or dry biomass previously suspended.

To sludge digestion becomes the digested sludge, d. h., the digestate mechanically dehydrated. Preferably, a combined sludge dewatering machine arrives used for thickening and drainage to the water content to reduce to the required extent.

at a sludge dewatering machine is one Compact plant for the mechanical dewatering of sludge, to achieve a degree of dewatering over the purely static drainage of gravity goes out. For this Forces are applied to the water from the mud out transport. Decanter centrifuges use centrifugal forces. Chamber filter presses or belt filter presses use the mechanical Applied compressive force and vacuum drum filter the atmospheric Compressive force.

Of the dehydrated digestate should have a dry matter content of about 25%. The sludge then becomes a sludge drying plant supplied to a defined residual moisture content to be dried. This determines the residual moisture content according to the nature of the intended use of the dried fermentation residue. A possible drying can be done by a solar drying take place at which much of the drying over the so-called glasshouse effect takes place.

To For solar drying, the following should be noted. This will get attachments used for sludge drying, the so-called greenhouse effect use, like this in glassed greenhouses is to be found. Mud can thin over a moving floor Layers introduced and with the help of a conveyor and turning system slowly being transported through the glasshouse with harrow pins. The drying takes place by the solar radiation and can by Bodenheizung get supported.

additionally a heating system such as underfloor heating, waste heat can be used can be fed, the z. B. from the biogas or in the implementation of biogas.

The dried fermentation residues can be exploited in different ways. So can dried Fermentation residues as substitute fuels in industry or fired in power plants. For this it is necessary that the fermentation residues preferably formed in pellets have a residual moisture content of less than 10%. This value can by means of the sludge drying as the solar drying readily be achieved. Is according to the digestate used, so will the primary use of fossil fuels reduced.

It However, there is also the possibility of dried fermentation residues as a nutrient fertilizer due to agriculture. This corresponds to a purely material recovery. In this way become phosphate fertilizers from finite deposits and elaborately produced with fossil primary energy Replaces nitrogen fertilizer.

• – Schwermetalleinträge aus Abschwämmungen bei Oberflächenabfluss sind ausgeschlossen,
• – die Transportkosten der Gärrückstände sind nach der Trocknung stark reduziert,
• – die Trocknung bewirkt neben der Faulung eine maßgebliche Hygienisierung der Gärrückstände.

For agricultural utilization, there are several advantages to the disposal concept according to the invention:

• - Heavy metal entries from surface runoff scum are excluded,
• - the transport costs of digestate are greatly reduced after drying,
• - The drying causes in addition to the digestion a significant sanitation of digestate.

The incurred in both the first reactor and in the second reactor Biogas can be used in various ways, with the possibilities from electricity and heat requirements in sewage and sludge treatment or depend on the area from which the sewage originates, ie from the settlement area of households.

A direct utilization of the biogas is that a power generation takes place. A gas turbine or a combined heat and power plant can be used for this purpose. The resulting waste heat can be used to heat the anaerobic reactor (first reactor) or the digester (second reactor) and optionally still excess heat for sludge drying. Should be more Excess heat available, other heat consumers can be supplied.

alternative For power supply, the biogas can be used directly as fuel become. So can a direct fire of a sludge drying plant respectively. Biogas utilization as fuel is also an option. So gas bottles can be bottled for household purposes or after appropriate gas treatment an infeed into a gas network. After further processing leave open up further uses such. B. a plant for the production of fuel from biogas.

The in the houses accumulating rainwater should preferably decentralized collected and processed to a separate pipeline network of large total area and large pipe diameters to avoid. This can be significant investment and Operating costs are saved.

to Treatment of contaminated rainwater come procedures such as Solid / liquid separation is used in which both floating as well as sedimenting substances are separated. Depending on the others Use of rainwater can be a fine cleaning by means of micro-sieving or microfiltration.

The so treated rainwater can be cached in operating water tanks become. This process water can be used for external cleaning, used for street cleaning or fire extinguishing water become. Excess operating water should be Water management, d. h., into the groundwater seep or into surface waters of recreational areas used or derived in rivers.

According to the invention an urban supply and disposal concept with full utilization of wastewater and Organic waste provided. Including Rainwater uses the concept of supplied water media and food as well as the naturally accumulating media rainwater and growing biomass almost completely, leaving out the supply and disposal of a settlement with regard to the said Media almost no emissions and residues result. Consumption of drinking water for the household and for public use in the settlement becomes reduced. The regenerative energy potential in water and in the Biomass is fully utilized. This results in an energy self-sufficient disposal.

The Wastewater streams are treated and irrigated or infiltration into the natural water cycle, wherein the treatment effort to clean the respective Wastewater flow based on its degree of contamination. The environmental compatibility is maximum due to the nearly zero emission. Despite extensive full use and nearly zero emission, however, is basically none direct reuse so that there are no hygienic risks which depend on the reliability of technical systems.

Further Details, advantages and features of the invention do not arise only from the claims, the features to be taken from them - for themselves and / or in combination - but also from the following Description of the drawing to be taken embodiment.

The single figure shows a schematic diagram of an urban disposal and supply concept for a settlement, which has a large number of houses 10 includes. The term "settlement" should not be understood as limiting, but may also include villages or cities.

About a vacuum sewer system - also vacuum sewerage 12 called - in the houses 10 accumulating water, ie gray and black water, as well as shredded kitchen waste 16 via vacuum lines 18 a collection container 20 fed.

From the collection container 20 The domestic waste collected in this way becomes a first reactor 22 over a line 24 fed, in which an anaerobic biological treatment with 3-phase separation takes place. In the reactor 22 it is in particular a high-performance reactor or at least a reactor in which, with a residence time of less than 24 h, a degradation rate of 60% -80% of the organic cargo is made possible.

In the first reactor 22 or anaerobic reactor separate biogas, anaerobically pretreated wastewater and incompletely fouled sludge, which are further treated according to the invention separately.

The anaerobically pretreated wastewater is sent via a pipe 26 a second biological treatment stage 28 supplied to remove residual degradable organic matter. The second biological treatment is carried out by means of an aerobic biocynosis, preferably a contact biology method 30 in which the biomass is immobilized on carriers. Because of the anaerobic pretreatment, the oxygen demand and thus the energy consumption for the ventilation fan is comparatively low. As a carrier material, a fixed bed, a fluidized bed or other regularly immersing contactors can be used. In the corresponding contact biology method 30 comparatively little excess biomass is formed. In the process stage 28 that the contact biology 30 may include a solids separation step 32 be integrated or connected. This may in particular be a microsieve, a microfiltration or an ultrafiltration for solids separation. This is anaerobic biologically in the reactor 22 , aerobic-biological in which by the contact biology (stage 30 ) and mechanically through microsieving (step 32 ) by means of z. B. microfiltration or ultrafiltration clarified wastewater can then be used directly for irrigation to supply the still contained valuable vegetation (compound 34 to the vegetation).

The one in the treatment stage 28 accumulated solid content is via a line 36 a second reactor 38 fed, in which an anaerobic biological treatment takes place. In the reactor 38 also leads a line 40 that from the first reactor 22 and incurring incompletely fouled sludge resulting from the anaerobic treatment of domestic sewage.

In other words, the sludge from the anaerobic reactor 22 and the sludge from separated biomass of the aerobic treatment 28 sludge digestion in the second reactor 38 fed. These Dünnschlämmen dry biomass such. As other household organic waste, green cuttings from the settlement or organic residues from the surrounding agriculture to be designated as a digester second reactor 38 be fed to fumigate the combined organic waste and biomass in a co-digestion. The addition of dry biomass is through the pipe 40 symbolizes.

ever according to ratio between supplied sludge and fed dry biomass results in a particular Dry matter content for the sludge, the total of the Faulung is supplied. The dry matter content should be above 50 g / l, so that, if necessary, sludge previously thickened or dry biomass previously suspended.

The digested sludge, ie the fermentation residue is then in a sludge dewatering machine 42 dehydrated and dried to the required extent. Then to set a desired residual moisture content in a system 44 to be additionally dried as solar drying plant. At the solar drying plant 44 Drying takes place according to the so-called glasshouse effect. Furthermore, over in the plant 44 existing heaters additional heating and thus drying done. The heating can be like underfloor heating 46 with waste heat via a pipe 48 be fed by a recycling facility 50 for that both in the first reactor 22 as well as in the second reactor 38 originating biogas comes.

The in the drying plant 44 dried fermentation residues can then z. B. via a conveyor 51 a silo 52 are supplied from which the digestate is removed. Previously, the fermentation residues can be pressed in pellet form.

A Use of dried fermentation residues may be directly in the form of agricultural exploitation, as a nutrient fertilizer, or as a substitute fuel in industrial and power plants.

The from the first and second reactor 22 . 38 accumulating biogas are transmitted via lines 54 . 56 the gas utilization device 50 fed. It may be z. B. in the event that it is a generation of electricity from the biogas, to act a gas turbine or a combined heat and power plant. The resulting waste heat can then for heating the anaerobic reactor (reactor 22 ) or the digester (reactor 38 ) be used. However, the heat can also be used for the solar drying plant 44 or used for other heat consumers.

alternative The biogas can be used directly as fuel. exemplary is the direct firing of a sludge drying plant. Also a bottling in gas bottles or a feeding in a gas network after gas treatment is possible.

That in the houses 10 accumulating rainwater is through lines 57 a solid / liquid separation plant 58 supplied, in which both floating and sedimenting substances are separated. The solid / liquid separation plant 58 Optionally, a microsieve or microfiltration device may be used 60 be downstream to make a fine cleaning.

The treated rainwater can be temporarily stored in service water tanks and for exterior cleaning, street cleaning or used as extinguishing water. excess Process water is fed to water management, d. H. seeped into groundwater or in surface waters used by recreational areas or in running waters derived.

If purified domestic wastewater is also to be supplied to the treated rainwater, it is necessary that these be freed from nitrogen and phosphorus. For this purpose, it is provided that in the first reactor 22 over the line 26 taken anaerobically treated wastewater before feeding into the aerobic biological treatment stage 28 a precipitation of nitrogen and phosphorus by means of the so-called MAP precipitation is performed.

The floats of rainwater treatment, ie those in the solid / liquid separation stage 58 can accrue to the second reactor 38 be supplied. The sediments and residues from the solid separation of the rainwater treatment (stage 58 ) are dewatered and dumped because of the possibility of having elevated levels of heavy metals.

Since all three phases of the anaerobic reactor 22 be treated further, there are no residues.

The thin sludge or the concentrate from the solids separation of the aerobic treatment 28 of domestic sewage becomes the second reactor 38 fed.

All wastewater from any required pre-thickening, post-thickening, dehydration and drying of digestate are fed into the first reactor, ie the anaerobic reactor 22 , returned.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102005063228 A [0003]

Claims (34)

Process for the treatment of household waste domestic sewage produced by means of a vacuum sewage system and then treated anaerobically and / or aerobically, marked by the process steps: - Enriching the domestic sewage with organic matter and transport of the enriched waste water in a collecting container by means of the vacuum sewage system, - anaerobic pretreatment of enriched domestic sewage in a first Reactor, Separate removal from the first Reactor of biogas produced by the pretreatment, anaerobic pretreated waste water and incompletely fouled sludge, - in which Energy is extracted from the biogas that pretreated anaerobically Wastewater is aerobically-biologically treated and incomplete rotted sludge anaerobically treated in a second reactor becomes. Method according to claim 1, characterized in that that the domestic sewage through crushed kitchen waste is enriched organically. Method according to claim 1 or 2, characterized that transported by the means of the vacuum sewage system and then to the first reactor fed enriched domestic Sewage foreign and rainwater is kept away. Method according to at least one of the preceding Claims, characterized in that the enriched domestic wastewater over a period t in the first anaerobic biologically pretreated with t <24 h, wherein the first reactor is operated such that during the pretreatment time organic solids between 60% and 80% are degraded. Method according to at least one of the preceding Claims, characterized in that in the first reactor by heat supply mesophilic or thermophilic conditions be set. Method according to at least one of the preceding Claims, characterized in that the from the first Reactor withdrawn anaerobically treated wastewater by means of a aerobic biocynosis, preferably by contact biology method, is treated. Method according to at least claim 1 or 6, characterized characterized in that the aerobic biological treatment in a Fluid bed, a fixed bed reactor or carried out in a reactor is immersed in the contact pores in the wastewater. Method according to at least Claim 6, characterized that from the aerobically treated wastewater solids preferably separated by Mirkosiebung, microfiltration or ultrasonic filtration become. Method according to claim 8, characterized in that that the separated solids are fed to the second reactor become. Method according to at least Claim 5, characterized that the aftertreated wastewater after separating the solids z. B. is used for irrigation. Method according to at least one of the preceding Claims, characterized in that from the anaerobic pretreated domestic wastewater and before its aerobic-biological After treatment at least nitrogen and phosphorus precipitated become. Method according to claim 11, characterized in that precipitation is by MAP precipitation. Method according to at least claim 1, characterized in that that in the aerobic treatment a biological nitrogen and Phosphorus elimination is integrated. Method according to at least one of the preceding Claims, characterized in that the second reactor additionally fed dry or suspended biomass becomes. Method according to at least claim 1, characterized in that that the solids separated from the aerobic-biologically treated wastewater be supplied to the second reactor. Method according to at least one of the preceding Claims, characterized in that in the second Reactor by heat supply mesophilic or thermophilic conditions be set. Method according to at least one of the preceding Claims, characterized in that a partial flow of the digested sludge taken from the second reactor (digestate) recycled as contact sludge in the inlet of the first reactor becomes. Method according to at least one of the preceding claims, characterized in that the extracted from the second reactor out Rotten sludge (fermentation residue) is drained and dried. Method according to at least Claim 18, characterized that the digested sludge at least on a dry matter content 25% thickened or dehydrated and then dried becomes. Method according to at least Claim 18, characterized that the drying is carried out by solar drying. Method according to at least Claim 18, characterized that the dried digested sludge is used as fuel becomes. Method according to at least Claim 18, characterized that the dried digested sludge as nutrient fertilizer is used. Method according to at least Claim 18, characterized that the dried digested sludge is pressed into pellets. Method according to at least claim 1, characterized in that that withdrawn from the first reactor and the second reactor Biogas is used for electricity generation or as fuel. Method according to at least Claim 24, characterized that the biogas is fed to a gas turbine or a combined heat and power plant. Method according to at least Claim 24, characterized that in the power generation of the biogas accumulating waste heat for heating the first and / or second reactor and / or for drying the digested sludge is used. Method according to at least one of the preceding Claims, characterized in that that of the domestic Wastewater kept rainwater by solid / liquid separation is spread. Method according to at least one of the preceding Claims, characterized in that the processed Rainwater of a fine cleaning such as micro-sieving or microfiltration is subjected. Method according to at least one of the preceding Claims, characterized in that the processed Rainwater preferably collected and for external cleaning or street cleaning or used as extinguishing water becomes. Method according to at least one of the preceding Claims, characterized in that the processed Rainwater is fed to a water management. Method according to at least one of the preceding Claims, characterized in that in the rainwater treatment resulting flotate is fed to the second reactor. Method according to at least one of the preceding Claims, characterized in that in the rainwater treatment accumulating sediments and / or residues from the Dewatering of the rainwater treatment drained and be deposited. Method according to at least one of the preceding Claims, characterized in that wastewater from any necessary pre-thickening, post-thickening, Dewatering and / or drying the digested sludge first reactor are supplied. Urban removal and care system for treatment of domestic waste accumulating in settlements Use of a method according to at least one of the claims 1-33.