GB2118537A - Method of concentration of biological, especially activated, sludge - Google Patents
Method of concentration of biological, especially activated, sludge Download PDFInfo
- Publication number
- GB2118537A GB2118537A GB08309307A GB8309307A GB2118537A GB 2118537 A GB2118537 A GB 2118537A GB 08309307 A GB08309307 A GB 08309307A GB 8309307 A GB8309307 A GB 8309307A GB 2118537 A GB2118537 A GB 2118537A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sludge
- concentration
- biological
- sludges
- physical structure
- 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.)
- Granted
Links
- 239000010802 sludge Substances 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 37
- 230000000694 effects Effects 0.000 claims abstract description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 7
- 239000001301 oxygen Substances 0.000 claims abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 7
- 229910017464 nitrogen compound Inorganic materials 0.000 claims abstract description 5
- 150000002830 nitrogen compounds Chemical class 0.000 claims abstract description 5
- 150000002823 nitrates Chemical class 0.000 claims abstract description 3
- 150000002826 nitrites Chemical class 0.000 claims abstract description 3
- 238000005188 flotation Methods 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 238000005119 centrifugation Methods 0.000 claims description 3
- 230000002269 spontaneous effect Effects 0.000 claims description 2
- 102000004190 Enzymes Human genes 0.000 abstract description 2
- 108090000790 Enzymes Proteins 0.000 abstract description 2
- 239000000725 suspension Substances 0.000 description 11
- 239000000126 substance Substances 0.000 description 8
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical class [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 6
- 244000005700 microbiome Species 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 229910002651 NO3 Inorganic materials 0.000 description 4
- 210000004027 cell Anatomy 0.000 description 4
- 230000029087 digestion Effects 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000002028 Biomass Substances 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000000855 fermentation Methods 0.000 description 2
- 230000004151 fermentation Effects 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000036571 hydration Effects 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000693 micelle Substances 0.000 description 2
- 239000005416 organic matter Substances 0.000 description 2
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 description 2
- 238000011282 treatment Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241001430149 Clostridiaceae Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 102000035195 Peptidases Human genes 0.000 description 1
- 108091005804 Peptidases Proteins 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000036782 biological activation Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 210000000170 cell membrane Anatomy 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229940088598 enzyme Drugs 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000002054 inoculum Substances 0.000 description 1
- 159000000014 iron salts Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- -1 nitrate ions Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000011197 physicochemical method Methods 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Inorganic materials [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 229940024999 proteolytic enzymes for treatment of wounds and ulcers Drugs 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 235000010288 sodium nitrite Nutrition 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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
- C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
- C02F3/342—Biological treatment of water, waste water, or sewage characterised by the microorganisms used characterised by the enzymes used
-
- 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
- C02F3/28—Anaerobic digestion processes
-
- 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
- C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/24—Treatment of water, waste water, or sewage by flotation
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Biodiversity & Conservation Biology (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treatment Of Sludge (AREA)
- Enzymes And Modification Thereof (AREA)
- Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
Abstract
Activated sludge is biologically converted into a form in which it is readily concentrated by conventional means. The method of concentration comprises adding to the sludge oxygen-containing nitrogen compounds, most suitably nitrates or nitrites, in an amount of 50 to 1000 g/m<3> under anaerobic conditions so as to form sludge flakes with an altered physical structure, formed by enzyme activity, which are directly concentrated.
Description
SPECIFICATION
Method of concentration of biologically, especially
activated, sludge
The subject of the invention is a method of concentration of biological, especially activated, sludge by a change in the physical structure of the sludge brought about bythetreatment described below.
These sludges are formed in waste watertreatment by so-called biological filtration and biological activation. During these purification processes various microorganisms present in the waste water proliferate and utilize soluble impurities for biomass production.
The waste water is thus freed of the dissolved substances, purified water is then returned to waterways. The microorganisms separated bysedimenta- tion form a biological sludge.
The sludge is further processed with the aim of complete disposal orfurther utilization.
Sludge disposal is achieved by classical methods based on sludge septicization or digestion. This is mainly performed in so-called sludge fields or sludge lagunes in which seepage and water removal by evaporation take place and the sludge is digested under combi#ned aerobic and anearobic conditions.
The treatment requires large areas and had negative environmental effects. A method with less adverse environmental effects is digestion under anaerobic conditions. However, it requires high investments to build sealed pressure digestion chambers. In these chambers a deep destruction takes place during which the sludge is nearly mineralized. This is accompanied by large losses and debasement of organic matter and the evolution of gases such as hydrogen, ammonia, methane, carbon dioxide, hydrogen sulphide, nitrogen, etc. The digested sludge from both treatments can be used only as a fertilizer. Energy can be generated in the form of flammable gases (methane, hydrogen sulphide, hydrogen).
As the sludge biomass contains about40% protein per dry weight, attempts have been made to use some sludgetypesasfodder. For this purposethesludge biomass has to be dried. Before the drying the sludge hasto be dehydrated as much as possible. The dehydration and concentration of biological sludges is known, among experts, to be avery difficult problem.
This is due to the factthat activated sludge has an unsuitable physical structure. Due to this structure it binds large amounts ofwaterwhich can be removed only with difficulty. The sludge istherefore highly voluminous.
Biological sludge obtained by mere sedimentation has a dry weight of about 1%. It is concentrated by so-called pressure floatation which is based on forcing finely dispersed compressed air through the sludge suspension. The air bubbles carry the sludge flakes to the surface. The floated sludge contains a maximum of 5% dryweight.The concentration is caused merely by a sharper separation ofthe liquid phase from the sludge suspension whereas the physical structure remains unchanged. The floatation method requires considerable investments and energy costs associated with the production of compressed air. The sepa rated biomassisfurtherconcentrated in decanting centrifuges.The final concentration reaches a maximum of 10% dryweightowing to the unchanged physical structure. To increase the effect of centrifugation, the physical structure of the processed sludge is improved by physico-chemical methods such as the application of aluminium or iron salts, polyelectroiytes, etc., which cause a change in the electric charge ofthe sludge micelles and their hydration layer. Consequently, the water bound by adhesion forces to the large surface of spherical particles is released. The change in the physical structure caused by the procedure ensures a good concentration in the decanting centrifuge, which approachestheconcentrationachieved bythecentri fugationofunicellularmicroorganismssuch as yeasts.This procedure requires also large expenditures, especially due to the cost of chemicals~ polyelectrolytes-which rises constantly. These disadvantages are avoided by the method described in the present invention, in which a change in the physical structure ofthe sludge is achieved by a low-cost process using the enzymic activity of microorganisms present in the biological, especially activated, sludge.
The unsuitable physical structure of the sludge is caused, in addition to the above mentioned hydration layerofmicroorganisms and extracellularwater inside the sludge micelle, also bythefactthat a number of microorganisms present in the sludge form extracellularslimeenvelopes made of polysaccharides which are present in the cell. The slime substances have a high water-binding ability and are the main cause of the poor dehydratability of the sludges.
The current attempts at improving the physical structures of sludges do not take this fact into consideration and the traditional procedures have thus a low efficiency.
The change in the physical structure of the sludge by enzymic processes hasforthefirsttime been dealt with in the Czechoslovak patent no. 153046 "A method of concentrabon of organic sludges" (Barta, Fechtner, Hanzlicvek, Verner, Vesely') and Czechoslovak patent no. 147846 "A method of reducing the liquid phase content in organic sludges" (Barta, Dyr, Hanzlícek, Verner, Vesely). According to these procedures, focusing mainly on the so-called biological floatation, a substantially higher concentration oftheflotated solid phase of the sludge suspension and a considerable saving of energy in comparison to the so-called pressure flotation is achieved by a controlled fermentation using previously multiplied pure or sludge suspension.Selected cultures of denitrification bacteria with orwithoutthe addition of nitrate ions. These procedures are much cheaper than the above methods but are time-consuming and require a two-stage manipulation and large-volume tanks for preparation of inoculum and the biological flotation itself.
The method of concentrating biological, especially activated, sludges according to the present invention
This print embodies corrections made under Section 117(1) of the Patents Act 1977.
eliminates some of these shortcomings.
It is based on addition to the sludges of oxygen
containing nitrogen compounds, most suitably ni
trates and/or nitrites, in an amount of 50 to 2000 g/m3 ata temperature of 5to 45"C and at pH 5to 8,5. After 15
min to 2 hours the sludge flakes formed due to the enzymic activity and possessing a changed physical structure are directly concentrated by centrifugation.
In contrast to the above-mentioned Czechoslovak patents the process takes place without any added microorganisms and it eliminates a prolonged fermentation which takes several tens of hours, as well as biological flotation. It involves merely a short intensive activity of microbial cells present in the sludge, which is brought about by the addition of a relatively high amount of oxygen-containing nitrogen compounds.
This procedure, which affords sludge flakes with altered physical structure, permits a direct concentration of native sludge from 1 to 2% dry weight to 14to 16% dry weight on a decanting centrifuge, i.e. without flotation.
We found that the wide range of microorganisms present in the sludge are capable to change, in a very short time, the physical structure of the sludge to the required degree. Measurement of dissolved oxygen showed that the level of dissolved oxygen in the sludge suspension layer and the adjacent overlying water zone decreases rapidly. The resulting anaerobic environment ensures a slight activity of the dentrification bacteria abundant in the sludge. We also found that during the intensive activity of these nitratereducing organisms their enzyme equipment permits them to utilize the cell slime coats as sources of carbon which is indispensable for their activity as much of the nitrogen compounds are. The slime coats are thus hydrolyzed.In addition, some ofthese nitrate-reducing organisms, especially Clostridiaceae, produce exogenous proteolytic enzymes which attack the cell membranes of cells present in the sludge. The overall result of these enzymic processes is an initially very slight degradation such as encountered inthedigestion process. This process is sufficient to bring about the required change in physical structure without any losses or debasement of the organic matter in the sludge.
The creation of optimum conditions for the induction of spontaneous intensive activity of nitratereducing organisms, which ensure the attainment of the required effect, was thoroughly studied and the conditions were precisely determined. They comprise merely a sufficient addition or nitrates and maintenance of anaerobic or, at least, microaerophilic conditions,temperature and the pH value.
Suitable sources of nitrate or nitrite are sodium, potassium, or, in particular, ammonium or calcium nitrates which are used in agriculture as saltpeter fertilizers. They are cheap and readily soluble. According to the type and composition of the sludge the compounds are added in amounts of 40 to 2000 g NO3 per 1 m3 sludge suspension in the form of 10 to 20%
solution. The optimum pH value is in the range of 7,0 to 8,5. The process proceeds well at temperatures of
15 to 37 C. Generally, the temperature should not be
below 5 C. Anaerobic conditions are defined by the concentration of dissolved oxygen a maximum of 0,1 mg 02 per litre of sludge suspension.
Underthese conditionsthewhole process is sub stantiallysimplified and enormously shortened-the required intervals are ofthe order of minutes- and both investment and operational costs decrease markedly. The fact that the flotation step is superfluous makes it possible to effect the process in a continuous mode in a relatively small-volume reactor.
The amount of nutrate added which is needed to ensure satisfactory intensity ofthe process depends on the type, composition and properties of the processed biological sludge. An optimum andecono mically advantageous addition is such that the content of NO3 in the separated sludge liquor after the process is not higherthanthe original content in the liquid phase ofthe processed sludge suspension.
In the following we present examples of the method of concentration of biological sludges according to the invention.
Example 1
3000 g of technical purity calcium nitrate in the form of 20% solution is added to 10 m3 of suspension of activated sludge containing 80kg of suspended insoiuble substances. The mixture is homogenized for 1 Oto 15 sec and after 15 min it is centrifuged on a decanting centrifuge. The process yields 550kg sludge concen tratewith a dryweightof 14% which represents 96,25% of the original amount of insoluble substances.
Example 2
The procedure is the same as in example 1 but 3000
I sludge containing 0,8% suspended insoluble substances is continuously supplied with 10001 of processed sludge suspension per 1 hourtogetherwith 1,5 1 20% solution oftechnical purity calcium nitrate, under constant stirring at the input of a continuous reactor.
The remaining separated volume of the reactor is without agitation. The reactor effluent is 1 001,5 1 sludge with altered physical structure per 1 hour. The effluent is continuously centrifuged in a decanting centrifuge to yield 56 kg/h of a sludge concentrate with a dry weight of 14%.
Example 3
Avolume of 20 m3 of suspension of superfluous activated sludge with a 0.5% concentration of sus-pended insoluble compounds is supplied in a mixing tank with 60 litres ofiO% of solution of sodium nitrite, homogenized for 30 sec. and immediately transferred into a flotation tank. After 12 h theflotated layer of insoluble substances is removed by a scraper. The procedure yields 1.500 kg sludge concentratewith a dry weight of 6%, suitable forfurtherprncessing in anaerobic digestion tanks. The removed flotated layer represents 90% ofthe introduced insoluble substances.
Claims (5)
1. A method of concentration of biotogicat acti- vated sludges defined by the fact that the sludges are supplied with oxygen-containing nitrogen com
pounds, most suitable nitrates or nitrites, in an amount of 50 to 1000 g/m3 at a temperature of 5 to 45"C and at pH 5to 8.5 under anaerobic conditions and after
15 min. to 3 hours the sludge flakes with altered
physical structure, formed by enzymic activity, are directly concentrated.
2. Method according to claim 1 inwhichthe concentration is done by centrifugation.
3. Methodaccordingtoclaiml inwhichthe concentration is achieved by spontaneous flotation.
4, A method as claimed in claim 1 and substantially as hereinbefore described.
5. A method of concentration of biological activated sludges substantially as hereinbefore described in any one of the examples.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CS822450A CS228403B1 (en) | 1982-04-06 | 1982-04-06 | Method of concentration biologic,particularly activated sludge |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8309307D0 GB8309307D0 (en) | 1983-05-11 |
| GB2118537A true GB2118537A (en) | 1983-11-02 |
| GB2118537B GB2118537B (en) | 1986-01-08 |
Family
ID=5361682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8309307A Expired GB2118537B (en) | 1982-04-06 | 1983-04-06 | Method of concentration of biological especially activated sludge |
Country Status (7)
| Country | Link |
|---|---|
| CS (1) | CS228403B1 (en) |
| DE (1) | DE3312381A1 (en) |
| DK (1) | DK150083A (en) |
| FR (1) | FR2524459B1 (en) |
| GB (1) | GB2118537B (en) |
| IT (1) | IT1163228B (en) |
| SE (1) | SE450893B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2122983C1 (en) * | 1996-01-11 | 1998-12-10 | Государственный научно-исследовательский и проектно-конструкторский институт по развитию и эксплуатации флота "Гипрорыбфлот" | Method of preparing stabilized sludge inoculate and its storage |
| WO2023062233A1 (en) | 2021-10-14 | 2023-04-20 | Ocado Innovation Limited | Systems and methods for order processing |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9016505D0 (en) * | 1990-07-27 | 1990-09-12 | Applied Biotechnologies | Restoration and maintenance of the function of a trickling-percolating-filter |
| DE4138667A1 (en) * | 1991-11-25 | 1993-05-27 | Sued Chemie Ag | METHOD FOR DISCHARGING DRAIN CLEANER |
| FR2709304B1 (en) * | 1993-08-23 | 1995-11-24 | Omnium Traitement Valorisa | Process and installation for stabilizing and concentrating sludge with nitrogen oxides. |
| FR2732335B1 (en) * | 1995-03-31 | 1997-06-27 | Omnium Traitement Valorisa | SLUDGE STABILIZATION PROCESS |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1170618A (en) * | 1967-03-04 | 1969-11-12 | Ceskoslovenska Akademie Ved | A Method of Concentration of Organic Sludges |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE601668C (en) * | 1931-07-25 | 1934-08-25 | Ferdinand Fraensemeier | Process for maintaining the optimal hydrogen ion concentration for the anaerobic digestion of sewage sludge |
| JPS5245582A (en) * | 1975-10-09 | 1977-04-11 | Tokai Denka Kogyo Kk | Solid-liquid separation method of organic waste fluid sludge |
| SU1006394A1 (en) * | 1981-08-07 | 1983-03-23 | Ташкентский Филиал Всесоюзного Научно-Исследовательского Института Водоснабжения,Канализации,Гидротехнических Сооружений И Инженерной Гидрогеологии | Method for treating effluent precipitate |
-
1982
- 1982-04-06 CS CS822450A patent/CS228403B1/en unknown
- 1982-04-06 SE SE8202201A patent/SE450893B/en not_active IP Right Cessation
-
1983
- 1983-04-05 IT IT2045983A patent/IT1163228B/en active
- 1983-04-05 DK DK150083A patent/DK150083A/en not_active Application Discontinuation
- 1983-04-05 FR FR8305514A patent/FR2524459B1/en not_active Expired
- 1983-04-06 DE DE19833312381 patent/DE3312381A1/en active Granted
- 1983-04-06 GB GB8309307A patent/GB2118537B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1170618A (en) * | 1967-03-04 | 1969-11-12 | Ceskoslovenska Akademie Ved | A Method of Concentration of Organic Sludges |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2122983C1 (en) * | 1996-01-11 | 1998-12-10 | Государственный научно-исследовательский и проектно-конструкторский институт по развитию и эксплуатации флота "Гипрорыбфлот" | Method of preparing stabilized sludge inoculate and its storage |
| WO2023062233A1 (en) | 2021-10-14 | 2023-04-20 | Ocado Innovation Limited | Systems and methods for order processing |
| WO2023062228A1 (en) | 2021-10-14 | 2023-04-20 | Ocado Innovation Limited | Systems and methods for order processing |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2118537B (en) | 1986-01-08 |
| CS8202450A (en) | 1982-12-31 |
| IT1163228B (en) | 1987-04-08 |
| DK150083D0 (en) | 1983-04-05 |
| SE8202201L (en) | 1983-10-07 |
| DE3312381C2 (en) | 1991-04-25 |
| FR2524459A1 (en) | 1983-10-07 |
| IT8320459A0 (en) | 1983-04-05 |
| CS228403B1 (en) | 1984-05-14 |
| SE450893B (en) | 1987-08-10 |
| IT8320459A1 (en) | 1984-10-05 |
| FR2524459B1 (en) | 1985-11-29 |
| DE3312381A1 (en) | 1983-10-13 |
| DK150083A (en) | 1983-10-07 |
| GB8309307D0 (en) | 1983-05-11 |
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