EP0000861B1 - Process for the purification of organically polluted, calcium containing wastewater - Google Patents
Process for the purification of organically polluted, calcium containing wastewater Download PDFInfo
- Publication number
- EP0000861B1 EP0000861B1 EP19780100051 EP78100051A EP0000861B1 EP 0000861 B1 EP0000861 B1 EP 0000861B1 EP 19780100051 EP19780100051 EP 19780100051 EP 78100051 A EP78100051 A EP 78100051A EP 0000861 B1 EP0000861 B1 EP 0000861B1
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- EP
- European Patent Office
- Prior art keywords
- purification
- activated sludge
- value
- calcium
- wastewater
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/1205—Particular type of activated sludge processes
- C02F3/1215—Combinations of activated sludge treatment with precipitation, flocculation, coagulation and separation of phosphates
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/12—Activated sludge processes
- C02F3/26—Activated sludge processes using pure oxygen or oxygen-rich gas
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Definitions
- the invention relates to a process for purifying calcium-containing, organically contaminated wastewater by means of an activated sludge process with aeration with almost pure oxygen and / or with an oxygen-containing gas, in which a CO 2 -containing gas is converted into the in the aeration system in order to convert calcium hydroxide to calcium carbonate existing liquid is introduced.
- Calcium-containing, organically branched wastewater is particularly common in sugar production.
- the sugar industry has recently been using activated sludge processes for the purification of such waste water either instead of or in connection with the use of stacking ponds and oxidation ponds.
- a wastewater treatment process is known in which the floating and washing water accumulating in the sugar factory is circulated through a settling basin and the sludge transport water coming from the settling basin is first fed to an onshore basin and an anaerobic basin and then to a fermenter with a downstream secondary clarification basin. Sludge settled in the secondary clarifier is transported back into the fermenter, while purified water drawn off from the secondary clarifier can be returned to the settling basin of the wash and wash water circuit or fed to a receiving water.
- the fermenter can be operated with air or at least with oxygen-enriched air (see special print from the magazine "Zucker", 28th year, volume 10, pages 527 to 534, 1975).
- a decrease in the bacterial growth in the activated sludge system and thus a low degradation capacity can be caused by the fact that the wastewater accumulating in the settling basin of the wash and wash water circuit is due to the usually more or less high additions of calcium hydroxide (Ca (OH) 2 ) in the wash and water cycle to avoid undesirable bacterial growth in this cycle is strongly alkaline, pH values of up to 12 being achievable.
- Ca (OH) 2 calcium hydroxide
- the invention has for its object to develop a method for purifying calcium-containing wastewater, in particular from the highest possible degradation performance can be achieved.
- This object is achieved in that the introduction of CO 2 is carried out to the extent that the pH in the activation system is set between 6 and 8 and the concentration of activated sludge dry substance is above 8 kg / m 3 and the proportion of the organic substance therein. defined as loss on ignition at 30 to 70%, preferably at 40 to 60%.
- the activated sludge is weighted with the aid of calcium carbonate precipitated by the introduction of a CO 2 -containing gas, which leads to an increase in the concentration of the activated sludge dry substance, which generally indicates the proportion by weight of undissolved substances in a solid water mixture.
- the process according to the invention is advantageously carried out such that the pH in the activation system is adjusted to a value between 6.5 and 7.5 by the introduction of the CO 2 -containing gas.
- the pH in the activation system is adjusted to a value between 6.5 and 7.5 by the introduction of the CO 2 -containing gas.
- Waste water from the wash and wash water circuit of a sugar factory was taken from the drain of the mechanical sedimentation basin and sent to a semi-technical biological plant.
- the BOD 5 of the feed was 12000 mg / I, the COD 17000 mg / I, the pH 10-12 and the Ca content 3000 mg / I.
- the aeration tank of the plant was initially filled with activated sludge from a municipal wastewater treatment plant, which was characterized by a dry matter concentration of 4 mg / m 3 , a loss on ignition of 80% and a sludge index of 100 ml / g.
- a gas containing 60-70% O 2 and 30-40% CO 2 was introduced into the activation tank. This resulted in a pH of 6.5-7 in the pool.
- the dry matter concentration increased rapidly in the course of a short time and reached values of 20 to 40 kg / m 3 with a loss on ignition of 40-50% and a sludge index of 20-50 ml / g.
- BOD 5 room load of 5-10 kg / m 3 . d and a corresponding nominal aeration time of 30-60 hours
- BOD 5 values of 150-300 mg / 1 and COD values of 600-1200 mg / I were measured in the secondary clarifier.
- the Ca content of the drain was 600 mg / I, so it had decreased by 2400 mg / I, which corresponds to a precipitated amount of 6000 mg / I CaC0 3 .
- the CaC0 3 practically completely changes to 3350 mg / lCaO.
- About 2500 mg / I of excess sludge with an organic content of approx. 70% is produced from 12000 mg / I BOD S.
- the table below shows that in this way a sludge with an organic content of approx. 21% and a loss on ignition (previously defined as organic substance) of approx. 50% was formed.
- the inorganic part causes the good flocculation and settling properties.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Microbiology (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Activated Sludge Processes (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Description
Die Erfindung betrifft ein Verfahren zur Reinigung Calcium enthaltenden, organisch belasteten Abwassers mittels eines Belebtschlammverfahrens unter Belüften mit nahezu reinem Sauerstoff und bzw. oder mit einem Sauerstoff enthaltenden Gas, bei dem zum Umsetzen von Calciumhydroxid zu Calciumcarbonat ein CO2-haltiges Gas in die im Belebungssystem vorhandene Flüssigkeit eingeleitet wird.The invention relates to a process for purifying calcium-containing, organically contaminated wastewater by means of an activated sludge process with aeration with almost pure oxygen and / or with an oxygen-containing gas, in which a CO 2 -containing gas is converted into the in the aeration system in order to convert calcium hydroxide to calcium carbonate existing liquid is introduced.
Calcium enthaltende, organisch beastete Abwässer fallen insbesondere bei der Zuckerherstellung an. Von der Zuckerindustrie werden neuerdings zur Reinigung solcher Abwässer Belebtschlammverfahren entweder anstelle oder in Verbindung mit der Verwendung von Stapelteichen und Oxidationsteichen eingesetzt. So ist beispielsweise ein Abwasserreinigungsverfahren bekannt, bei dem das in der Zuckerfabrik anfallende Schwemm- und Waschwasser im Kreislauf über ein Absetzbecken geführt und das vom Absetzbecken kommende Schlammtransportwasser zunächst einem Auflandebecken und einem Anaerobbecken und danach einem Fermenter mit nachgeschaltetem Nachklärbecken zugeleitet wird. Im Nachlärbecken abgesetzter Schlamm wird in. den Fermenter zurücktransportiert, während aus dem Nachlärbecken abgezogenes gereinigtes Wasser in das Absetzbecken des Schwemm-und Waschwasserkreises zurück- oder einem Vorfluter zugeleitet werden kann. Der Fermenter kann dabei mit Luft oder zumindest mit Sauerstoff angereicherter Luft betrieben werden (siehe Sonderdruck aus der Zeitschrift "Zucker", 28. Jahrgang, Heft 10, Seite 527 bis 534, 1975).Calcium-containing, organically branched wastewater is particularly common in sugar production. The sugar industry has recently been using activated sludge processes for the purification of such waste water either instead of or in connection with the use of stacking ponds and oxidation ponds. For example, a wastewater treatment process is known in which the floating and washing water accumulating in the sugar factory is circulated through a settling basin and the sludge transport water coming from the settling basin is first fed to an onshore basin and an anaerobic basin and then to a fermenter with a downstream secondary clarification basin. Sludge settled in the secondary clarifier is transported back into the fermenter, while purified water drawn off from the secondary clarifier can be returned to the settling basin of the wash and wash water circuit or fed to a receiving water. The fermenter can be operated with air or at least with oxygen-enriched air (see special print from the magazine "Zucker", 28th year, volume 10, pages 527 to 534, 1975).
Wie sich gezeigt hat, verläuft der Betrieb solcher Klärananlagen nicht immer reibungslos. Häufig treten unkontrollierte Entartungen des Belebtschlammes auf, die erhebliche Störungen der Abbauleistung zur Folge haben und die auf ein unausgewogenes Nährstoffangebot, insbesondere bei Über- oder Unterbelastung der Anlagen zurückzuführen sind. Solche als Blähschlamm bezeichneten Entartungen können beispielsweise lange Bakterienfäden sein, die nur eine geringe Sinkgeschwindigkeit besitzen. Beim Auftreten eines solchen Blähschlamms erfolgt im Nachlärbecken nur eine sehr langsame Auftrennung in den Belebtschlamm, der in die Belebungsanlage zurückgenommen wird, und in den Klarlauf, der in den Vorfluter abgeleitet wird.As has been shown, the operation of such sewage treatment plants is not always smooth. Uncontrolled degenerations of the activated sludge often occur, which result in considerable disruption of the mining performance and which can be attributed to an unbalanced nutrient supply, in particular if the plants are overloaded or underloaded. Such degenerations, known as expanded sludge, can be, for example, long bacterial threads that have only a low sinking rate. When such expansion sludge occurs, there is only a very slow separation in the secondary clarification tank into the activated sludge, which is taken back into the aeration plant, and into the clear run, which is discharged into the receiving water.
Außerdem kann auch eine Verminderung des Bakterienwachstums im Belebtschlammsystem und damit eine geringe Abbauleistung dadurch bedingt sein, daß das im Absetzbecken des Schwemm- und Waschwasserkreislaufs anfallende Abwasser aufgrund der üblicherweise mehr oder minder hohen Zugaben von Calciumhydroxid (Ca(OH)2) in den Schwemm- und Wasserkreislauf zur Vermeidung eines in diesem Kreislauf unerwünschten Bakterienwachstums stark alkalisch ist, wobei pH-Werte bis zu 12 erreicht werden können.In addition, a decrease in the bacterial growth in the activated sludge system and thus a low degradation capacity can be caused by the fact that the wastewater accumulating in the settling basin of the wash and wash water circuit is due to the usually more or less high additions of calcium hydroxide (Ca (OH) 2 ) in the wash and water cycle to avoid undesirable bacterial growth in this cycle is strongly alkaline, pH values of up to 12 being achievable.
Aus der französischen Offenlegungsschrift 2 294 986 ist darüber hinaus ein Verfahren zur chemischen und biologischen Reinigung von Abwasser aus Industrie und Landwirtschaft bekannt, bei dem das zu behandelnde Abwasser zunächst unter Sauerstoffzufuhr mit Kalk zur Erzeugung eines pH-Wertes höher 9 vermischt, darauf die Mischung mit C02 gesättigt, der sich bildende Niederschlag mit Hilfe eines Koagulationsmittels ausgefällt und der Niederschlag von der Flüssigkeit abgetrennt wird. Anschließend wird das so behandelte Abwasser in ein Absetzbecken geleitet und der Klarwasserablauf biologisch weitergereinigt. Bei diesem Verfahren wird bereits das im Abwasser gelöste Calciumhydroxid durch Zufuhr eines CO2-haltigen Gases in einem unlöslichen Niederschlag in Form von Calciumcarbonat übergeführt, doch fehlen Angaben, wie eine möglichst hohe Abbauleistung des Reinigungsverfahrens zu verwirklichen ist.From the French laid-open specification 2 294 986 a process for the chemical and biological purification of wastewater from industry and agriculture is also known, in which the wastewater to be treated is first mixed with lime to produce a pH value higher than 9, then the mixture is mixed with it C0 2 saturated, the precipitate that forms is precipitated with the aid of a coagulant and the precipitate is separated from the liquid. The wastewater treated in this way is then passed into a settling basin and the clear water drain is further biologically cleaned. In this process, the calcium hydroxide dissolved in the wastewater is converted into an insoluble precipitate in the form of calcium carbonate by supplying a CO 2 -containing gas, but no information is available on how to achieve the highest possible degradation performance of the cleaning process.
Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Reinigung Calcium enthaltenden Abwassers, insbesondere aus.Zuckerfabriken, der eingangs genannten Art zu entwickeln, mit dem auf einfache Weise trotz der unter Umständen auftretenden Entartungen des Belebtschlamms und trotz des hohen pH-Wertes im Abwasser eine möglichst hohe Abbauleistung erzielt werden kann.The invention has for its object to develop a method for purifying calcium-containing wastewater, in particular from the highest possible degradation performance can be achieved.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die CO2-Einleitung in dem Maß durchgeführt wird, daß der pH-Wert im Belebungssystem zwischen 6 und 8 eingestellt und die Konzentration an Belebtschlammtrockensubstanz über 8 kg/m3 und der Anteil der organischen Substanz darin, definiert als Glühverlust auf 30 bis 70%, vorzugsweise auf 40 bis 60%, gehalten wird.This object is achieved in that the introduction of CO 2 is carried out to the extent that the pH in the activation system is set between 6 and 8 and the concentration of activated sludge dry substance is above 8 kg / m 3 and the proportion of the organic substance therein. defined as loss on ignition at 30 to 70%, preferably at 40 to 60%.
Mit Hilfe dieser Maßnahmen kann auf einfache und überraschend wirkungsvolle Weise eine hohe Abbauleistung des Reinigungsver-. fahrens verwirklicht werden. Mit der Einstellung des pH-Wertes im Belebungssystem zwischen 6 und 8 wird erreicht, daß bei nur gering saurem oder nur gering alkalischem Abwasser das Bakterienwachstum am günstigsten ist. Je mehr Calciumhydroxid dabei durch die Zufuhr des C02-haltigen Gases in Calciumcarbonat übergeführt wird, desto geringer wird der pH-Wert des Abwassers und stellt sich auf den gewünschten Bereich ein, in dem das Bakterienwachstum "erbessert und die Abbauleistung entsprechend erhöht wird.With the help of these measures, a high degradation capacity of the cleaning process can be carried out in a simple and surprisingly effective manner. driving can be realized. By setting the pH value in the aeration system between 6 and 8 it is achieved that the bacterial growth is most favorable with only slightly acidic or only slightly alkaline waste water. The more calcium hydroxide is converted into calcium carbonate by the supply of the CO 2 -containing gas, the lower the pH value of the wastewater and adjusts itself to the desired range in which the bacterial growth " improves and the degradation performance is increased accordingly.
Außerdem wird mit der Einstellung der Konzentration an Belebtschlammtrockensubstanz im Abwasser über 8 kg/m3 und des Anteils der organischen Substanz (definiert als Glühverlust) darin auf 30 bis 70%, vorzugsweise auf 40 bis 60%, erreicht, daß die Ausbildung und/oder die Auswirkungen des Blähschlamms weitgehend unterbunden und die Sinkgeschwindigkeit auch von fadenförmigen Bakterien in der Nachklärzone erhöht werden, so daß der vorhandene Belebtschlamm schneller in die Belebtzone zurückgeführt werden kann und dadurch letztlich mehr organische Substanz (=Bakterienmasse) zur Verfügung steht. Eine Erhöhung der Abbauleistung ist die Folge. Dabei wird der Belebtschlamm mit Hilfe des durch das Einleiten eines CO2-haltigen Gases ausgefällten Calciumcarbonats beschwert, was zu einer Erhöhung der Konzentration der Belebtschlammtrockensubstanz führt, die allgemein den Gewichtsanteil ungelöster Stoffe eines Feststoffwassergemisches angibt.In addition, with the adjustment of the concentration of activated sludge dry matter in the wastewater above 8 kg / m 3 and the proportion of the organic substance (defined as Loss on ignition) to 30 to 70%, preferably to 40 to 60%, achieved that the formation and / or the effects of the expanded sludge were largely prevented and the sinking rate of filamentous bacteria in the secondary clarification zone was increased, so that the activated sludge present in faster the revitalized zone can be returned and ultimately more organic substance (= bacterial mass) is available. The result is an increase in the mining capacity. The activated sludge is weighted with the aid of calcium carbonate precipitated by the introduction of a CO 2 -containing gas, which leads to an increase in the concentration of the activated sludge dry substance, which generally indicates the proportion by weight of undissolved substances in a solid water mixture.
Mit Vorteil wird das erfindungsgemäße Verfahren so durchgeführt, daß durch die Einleitung des CO2-haltigen Gases der pH-Wert im Belebungssystem auf einen Wert zwischen 6,5 und 7,5 eingestellt wird. Zur Einstellung dieser pH-Werte und der beiden übrigen Parameter ist es lediglich erforderlich, die Menge des eingeleiteten CO2-haltigen Gases in Abhängigkeit der zum Beispiel im Ablauf des Abwassers ermittelten Meßwerte für den pH-Wert und für die übrigen Parameter zu regeln.The process according to the invention is advantageously carried out such that the pH in the activation system is adjusted to a value between 6.5 and 7.5 by the introduction of the CO 2 -containing gas. To set these pH values and the two other parameters, it is only necessary to regulate the amount of introduced CO 2 -containing gas as a function of the measured values for the pH value and for the other parameters, for example determined in the waste water discharge.
Wie sich gezeigt hat, lassen sich mit den vorstehend angegebenen Werten gute Abbauleistungen erzielen. Ein Zahlenbeispiel soll diese Zusammenhänge verdeutlichen: Abwasser aus dem Schwemm- und Waschwasserkreislauf einer Zuckerfabrik wurde aus dem Ablauf des mechanischen Absetzbeckens entnommen und einer halbtechnischen biologischen Anlage zugeleitet. Der BSB5 des Zulaufs betrug 12000 mg/I, der CSB 17000 mg/I, der pH-Wert 10-12 und der Ca-Gehalt 3000 mg/I. Das Belebungsbecken der Anlage war zu Beginn mit Belebtschlamm einer kommunalen Kläranlage gefüllt worden, der durch eine Trockensubstanzkonzentration von 4 mg/m3, einen Glühverlust von 80% und einen Schlammindex von 100 ml/g gekennzeichnet war. Im Belebungsbecken wurde ein Gas eingetragen, das 60-70% O2 und 30-40% CO2 enthielt. Hierdurch stellte sich im Becken ein pH-Wert von 6,5-7 ein. Die Trockensubstanzkonzentration nahm im Verlauf kurzer Zeit stark zu und erreichte Werte von 20 bis 40 kg/m3 mit einem Glühverlust von 40-50% und einem Schlammindex von 20-50 ml/g. Bei einer BSB5-Raum- belastung von 5-10 kg/m3. d und einer entsprechenden nominellen Belüftungszeit von 30-60 Stunden wurden im Ablauf des Nachklärbeckens BSB5-Werte von 150-300 mg/1 und CSB-Werte von 600-1200 mg/I gemessen. Der Ca-Gehalt des Ablaufs lag bei 600 mg/I, hatte also um 2400 mg/I abgenommen, was einer ausgefällten Menge von 6000 mg/I CaC03 entspricht. Bei Bestimmung des Glühverlustes geht das CaC03 praktisch völlig in 3350 mg/lCaO über. Aus 12000 mg/I BSBS entstehen etwa 2500 mg/I überschußschlamm mit einem organischen Anteil von ca. 70%. Die anschließende Tabelle zeigt, daß auf diese Weise ein Schlamm mit einem organischen Anteil von ca. 21% und einem Glühverlust (zuvor definiert als organische Substanz) von ca. 50% entstanden ist. Der anorganische Anteil bewirkt die guten Flockungs- und Absetzeigenschaften.As has been shown, good degradation performance can be achieved with the values given above. A numerical example should clarify these relationships: Waste water from the wash and wash water circuit of a sugar factory was taken from the drain of the mechanical sedimentation basin and sent to a semi-technical biological plant. The BOD 5 of the feed was 12000 mg / I, the COD 17000 mg / I, the pH 10-12 and the Ca content 3000 mg / I. The aeration tank of the plant was initially filled with activated sludge from a municipal wastewater treatment plant, which was characterized by a dry matter concentration of 4 mg / m 3 , a loss on ignition of 80% and a sludge index of 100 ml / g. A gas containing 60-70% O 2 and 30-40% CO 2 was introduced into the activation tank. This resulted in a pH of 6.5-7 in the pool. The dry matter concentration increased rapidly in the course of a short time and reached values of 20 to 40 kg / m 3 with a loss on ignition of 40-50% and a sludge index of 20-50 ml / g. With a BOD 5 room load of 5-10 kg / m 3 . d and a corresponding nominal aeration time of 30-60 hours, BOD 5 values of 150-300 mg / 1 and COD values of 600-1200 mg / I were measured in the secondary clarifier. The Ca content of the drain was 600 mg / I, so it had decreased by 2400 mg / I, which corresponds to a precipitated amount of 6000 mg / I CaC0 3 . When determining the ignition loss, the CaC0 3 practically completely changes to 3350 mg / lCaO. About 2500 mg / I of excess sludge with an organic content of approx. 70% is produced from 12000 mg / I BOD S. The table below shows that in this way a sludge with an organic content of approx. 21% and a loss on ignition (previously defined as organic substance) of approx. 50% was formed. The inorganic part causes the good flocculation and settling properties.
Claims (2)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19772738309 DE2738309A1 (en) | 1977-08-25 | 1977-08-25 | METHOD FOR CLEANING CALCIUM-CONTAINING ORGANICALLY BURNISHED WASTE WATER |
| DE2738309 | 1977-08-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0000861A1 EP0000861A1 (en) | 1979-03-07 |
| EP0000861B1 true EP0000861B1 (en) | 1981-08-12 |
Family
ID=6017266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19780100051 Expired EP0000861B1 (en) | 1977-08-25 | 1978-06-01 | Process for the purification of organically polluted, calcium containing wastewater |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4227998A (en) |
| EP (1) | EP0000861B1 (en) |
| BR (1) | BR7805506A (en) |
| DE (1) | DE2738309A1 (en) |
| IT (1) | IT1098172B (en) |
| ZA (1) | ZA784822B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7906426A (en) * | 1979-08-27 | 1981-03-03 | Gist Brocades Nv | METHOD FOR PURIFYING WASTE WATER. |
| DE3202212A1 (en) * | 1982-01-25 | 1983-08-04 | Süddeutsche Zucker AG, 6800 Mannheim | METHOD FOR ANAEROBICLY DEGRADING CALCIUMION-CONTAINING, ALKALINE FLOOD AND WASHING WATERS |
| DE3917415C2 (en) * | 1989-05-29 | 1999-01-14 | Linde Ag | Wastewater treatment processes |
| GB9425110D0 (en) * | 1994-12-13 | 1995-02-08 | Boc Group Plc | Sewage respiration inhibition |
| DE10062878A1 (en) * | 2000-12-16 | 2002-06-27 | Messer Griesheim Gmbh | Processes for biological wastewater treatment |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2196840A (en) * | 1935-10-11 | 1940-04-09 | Micajah T Singleton | Sewage treatment |
| DE1484838A1 (en) * | 1964-02-04 | 1969-06-04 | Metallgesellschaft Ag | Process for the treatment of centrifugate, which falls during the dewatering of sewage sludge by means of decanting centrifuges |
| US3356609A (en) * | 1966-05-03 | 1967-12-05 | United Carbide Corp | Aerobic treatment of sewage |
| US3440166A (en) * | 1967-06-13 | 1969-04-22 | North American Rockwell | Waste treatment process with recycling flocculating agents |
| US3546111A (en) * | 1968-05-13 | 1970-12-08 | Ethyl Corp | Waste treatment |
| US3640820A (en) * | 1969-08-22 | 1972-02-08 | Nalco Chemical Co | Sewage treatment process |
| US3947350A (en) * | 1972-10-30 | 1976-03-30 | Envirotech Corporation | Process of preparing sewage sludge for dewatering |
| CS181403B1 (en) * | 1974-12-22 | 1978-03-31 | Svatopluk Mackrle | Method and device for with organic substances strongly polluted waste water treatment in industry and agriculture |
| DE2535837C3 (en) * | 1975-08-12 | 1984-09-13 | Bayer Ag, 5090 Leverkusen | Process for the biological treatment of wastewater in a cascade |
-
1977
- 1977-08-25 DE DE19772738309 patent/DE2738309A1/en not_active Withdrawn
-
1978
- 1978-06-01 EP EP19780100051 patent/EP0000861B1/en not_active Expired
- 1978-08-15 US US05/933,838 patent/US4227998A/en not_active Expired - Lifetime
- 1978-08-21 IT IT2686978A patent/IT1098172B/en active
- 1978-08-24 ZA ZA00784822A patent/ZA784822B/en unknown
- 1978-08-24 BR BR7805506A patent/BR7805506A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IT7826869A0 (en) | 1978-08-21 |
| IT1098172B (en) | 1985-09-07 |
| DE2738309A1 (en) | 1979-03-15 |
| BR7805506A (en) | 1979-04-17 |
| EP0000861A1 (en) | 1979-03-07 |
| ZA784822B (en) | 1979-08-29 |
| US4227998A (en) | 1980-10-14 |
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