GB2426973A - Method of deodorising dewater effluent - Google Patents
Method of deodorising dewater effluent Download PDFInfo
- Publication number
- GB2426973A GB2426973A GB0608357A GB0608357A GB2426973A GB 2426973 A GB2426973 A GB 2426973A GB 0608357 A GB0608357 A GB 0608357A GB 0608357 A GB0608357 A GB 0608357A GB 2426973 A GB2426973 A GB 2426973A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sodium percarbonate
- sodium
- coated
- effluent
- percarbonate
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 32
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims abstract description 54
- VTIIJXUACCWYHX-UHFFFAOYSA-L disodium;carboxylatooxy carbonate Chemical compound [Na+].[Na+].[O-]C(=O)OOC([O-])=O VTIIJXUACCWYHX-UHFFFAOYSA-L 0.000 claims abstract description 51
- 229940045872 sodium percarbonate Drugs 0.000 claims abstract description 51
- 229910000029 sodium carbonate Inorganic materials 0.000 claims abstract description 27
- 239000010865 sewage Substances 0.000 claims abstract description 17
- 239000000203 mixture Substances 0.000 claims abstract description 15
- 150000001875 compounds Chemical class 0.000 claims abstract description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910001868 water Inorganic materials 0.000 claims abstract description 12
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims abstract description 8
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims abstract description 8
- 239000008187 granular material Substances 0.000 claims abstract description 6
- 239000003513 alkali Substances 0.000 claims abstract description 5
- 239000004115 Sodium Silicate Substances 0.000 claims abstract description 4
- 229910000323 aluminium silicate Inorganic materials 0.000 claims abstract description 4
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims abstract description 4
- 239000001095 magnesium carbonate Substances 0.000 claims abstract description 4
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims abstract description 4
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000000391 magnesium silicate Substances 0.000 claims abstract description 4
- 229910052919 magnesium silicate Inorganic materials 0.000 claims abstract description 4
- 235000019792 magnesium silicate Nutrition 0.000 claims abstract description 4
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims abstract description 4
- 235000019341 magnesium sulphate Nutrition 0.000 claims abstract description 4
- 239000000429 sodium aluminium silicate Substances 0.000 claims abstract description 4
- 235000012217 sodium aluminium silicate Nutrition 0.000 claims abstract description 4
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims abstract description 4
- 235000017557 sodium bicarbonate Nutrition 0.000 claims abstract description 4
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052911 sodium silicate Inorganic materials 0.000 claims abstract description 4
- 238000000576 coating method Methods 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 16
- 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 claims 1
- PZZYQPZGQPZBDN-UHFFFAOYSA-N aluminium silicate Chemical compound O=[Al]O[Si](=O)O[Al]=O PZZYQPZGQPZBDN-UHFFFAOYSA-N 0.000 claims 1
- 239000011734 sodium Substances 0.000 claims 1
- 229910052708 sodium Inorganic materials 0.000 claims 1
- 239000010802 sludge Substances 0.000 abstract description 25
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 abstract description 6
- 239000003337 fertilizer Substances 0.000 abstract description 6
- 239000007800 oxidant agent Substances 0.000 abstract description 6
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052910 alkali metal silicate Inorganic materials 0.000 abstract description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 abstract description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 abstract description 3
- 235000014380 magnesium carbonate Nutrition 0.000 abstract description 3
- 235000017550 sodium carbonate Nutrition 0.000 abstract description 3
- 235000019794 sodium silicate Nutrition 0.000 abstract description 3
- 229910052938 sodium sulfate Inorganic materials 0.000 abstract description 3
- 235000011152 sodium sulphate Nutrition 0.000 abstract description 3
- 229910000288 alkali metal carbonate Inorganic materials 0.000 abstract description 2
- 229910052936 alkali metal sulfate Inorganic materials 0.000 abstract description 2
- 238000009332 manuring Methods 0.000 abstract description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 abstract description 2
- MWNQXXOSWHCCOZ-UHFFFAOYSA-L sodium;oxido carbonate Chemical compound [Na+].[O-]OC([O-])=O MWNQXXOSWHCCOZ-UHFFFAOYSA-L 0.000 abstract 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 9
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 6
- 235000011941 Tilia x europaea Nutrition 0.000 description 6
- 239000003925 fat Substances 0.000 description 6
- 239000004571 lime Substances 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 244000052769 pathogen Species 0.000 description 5
- 239000010801 sewage sludge Substances 0.000 description 5
- 241000607598 Vibrio Species 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000005864 Sulphur Substances 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 235000014113 dietary fatty acids Nutrition 0.000 description 2
- 239000000194 fatty acid Substances 0.000 description 2
- 229930195729 fatty acid Natural products 0.000 description 2
- -1 fatty acid calcium salts Chemical class 0.000 description 2
- 239000000344 soap Substances 0.000 description 2
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 description 1
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 description 1
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 description 1
- 241000193755 Bacillus cereus Species 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 241000193403 Clostridium Species 0.000 description 1
- 241000186781 Listeria Species 0.000 description 1
- 239000005642 Oleic acid Substances 0.000 description 1
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 description 1
- 241000607734 Yersinia <bacteria> Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- JYYOBHFYCIDXHH-UHFFFAOYSA-N carbonic acid;hydrate Chemical compound O.OC(O)=O JYYOBHFYCIDXHH-UHFFFAOYSA-N 0.000 description 1
- 238000009264 composting Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 125000004185 ester group Chemical group 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 230000007794 irritation Effects 0.000 description 1
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 description 1
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid Chemical compound CCCCCCCC\C=C/CCCCCCCC(O)=O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 description 1
- 230000001717 pathogenic effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 241001148471 unidentified anaerobic bacterium Species 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
- C01B15/055—Peroxyhydrates; Peroxyacids or salts thereof
- C01B15/10—Peroxyhydrates; Peroxyacids or salts thereof containing carbon
- C01B15/106—Stabilisation of the solid compounds, subsequent to the preparation or to the crystallisation, by additives or by coating
-
- 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
- C02F1/68—Treatment of water, waste water, or sewage by addition of specified substances, e.g. trace elements, for ameliorating potable water
-
- 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
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/06—Treatment of sludge; Devices therefor by oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
- C05F3/00—Fertilisers from human or animal excrements, e.g. manure
-
- 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
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/722—Oxidation by peroxides
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/02—Odour removal or prevention of malodour
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Water Supply & Treatment (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Treatment Of Sludge (AREA)
Abstract
A method of removing odours from effluents comprising contacting dewatered effluent with sodium percarbonate granules, wherein the granules are coated with a compound that is sparingly soluble in water. The granules may be coated with layers of a compound which includes alkali metal silicates, sulphates, carbonates and hydrogen carbonates, for example magnesium silicate, magnesium sulphate, magnesium carbonate, sodium silicate, sodium carbonate, sodium sulphate, sodium hydrogen carbonate or aluminium silicate. By adding the coated sodium percarbonate to sludge, the oxidising agent is present in the sludge for many days. Additionally an alkali, such as sodium carbonate, may be included so as to raise the pH of the sludge to more than 11. In the invention, dewatered sludge 1 is carried along a conveyer 2, a 1:1 mixture of coated sodium percarbonate and sodium carbonate is located in hopper 3, the sludge and the percarbonate mixture as deposited in the pre-mixer 4, this mixture is then carried along a screw conveyer 5 mixing the percarbonate and the sludge. The mixture is deposited in a storage or manuring container. The invention overcomes a problem nuisance odours in the use of sewage as a fertiliser.
Description
Method for treating effluent The invention relates to a method for
reducing nuisance odours present in effluent, and in particular to a method for reducing odours in sewage sludge.
Disposal of sewage is a major problem. There are approximately 9000 sewage treatment works in the United Kingdom alone, each producing over 200 tonnes of sewage waste and 11 billion litres of wastewater daily.
Typical methods for disposal include land fill, composting, burning and spreading on fields as a fertilizer.
The main problem of using sewage as a fertilizer is the nuisance odours. Sewage contains sulphur containing compounds including hydrogen sulphide and various mercaptans formed by anaerobic bacteria. These compounds are all foul-smelling and are highly volatile so need only be present at low concentrations to cause a nuisance. Sewage may be treated with oxidising agents in order to destroy these malodorous compounds. However, during subsequent storage, anaerobic conditions within a stockpile can cause these nuisance odours to be regenerated and then released once the stockpile is disturbed, for example for transport or land spreading. This is a real nuisance for the public and major reason for public opposition to land application of sewage.
Sewage must also be treated to reduce levels of pathogens before it can be used as a fertilizer.
This is usually achieved by the addition of lime to the dewatered sludge cake. Dewatered sludge cake typically comprises 7O8O% residual water, lime (CaO) reacts with the water to produce calcium hydroxide in an exothermic reaction. The heat produced pasteurises the cake, and also the pH of the cake is elevated to approximately pH 12, killing all bacteria.
The problems with using lime are that working conditions are not very favourable. Dissolving lime in water produces an output of heat of more than 1100 KJ per kg lime. This exothermic reaction increases the evolution of ammonia gas from the sludge. Ammonia is both unpleasant and dangerous to workers who may be overcome with the fumes. Ammonia can cause irritation to the eyes, nose and throat if not protected properly. Evolution of ammonia also reduces the N content of the sludge, so it has less value as a fertilizer. Liming also creates a very dusty atmosphere in the treatment plant which is unpleasant for workers.
In addition to the problems discussed above, when lime reacts with fats present in sewage sludge, fatty acid calcium salts are formed. These calcium salts are insoluble in water and form a precipitate (commonly known as lime soap), which stiffens up the cake and makes it more difficult to work with.
It would be desirable to provide an improved method for odour control in sewage waste.
One aspect of the invention provides a method for removing odours in dewatered effluent as specified in Claim 1.
A further aspect of the invention provides a product suitable for use with the method of the invention as specified in Claim 18.
A further aspect of the invention provides effluent treated according to the method of the invention as specified in Claim 20.
Preferred aspects of the invention are specified in the claims dependent on Claim 1.
The present invention offers an improved method that mitigates the aboveidentified problems, and provides longer term odour control in sewage waste.
The method of the invention uses an oxidising agent to destroy odours, the oxidising agent present in a stable form so that oxidising power continues to combat odours during storage for several weeks or months after mixing or processing.
Sodium percarbonate is an oxidising agent suitable for oxidising foulsmelling sulphur compounds found in sewage. Sodium percarbonate is an addition compound of sodium carbonate and hydrogen peroxide (2Na2CO33H2O2. It decomposes to oxygen, water and sodium carbonate, yielding approximately 13% of active oxygen. If sodium percarbonate is uncoated it decomposes rapidly in water. However, sodium percarbonate can be coated with layers of compounds which are sparingly soluble in water in order to improve stability. Coated sodium percarbonate is widely available commercially, for example from Solvay under the trade name OXPER .
Suitable coating compounds include alkali metal silicates, sulphates, carbonates and hydrogen carbonates; for example magnesium silicate, magnesium sulphate, magnesium carbonate, sodium silicate, sodium sulphate, sodium carbonate, sodium hydrogen carbonate or aluminium silicate.
By adding coated sodium percarbonate to sludge, the oxidising agent is present in the sludge for many days or weeks depending on the thickness of the coating or the number of coatings applied. The additive continues to oxidise the volatile sulphur compounds, removing odours for a long time after treatment. This is especially beneficial when transporting sludge.
Additionally treating sludge cake with an alkali, preferably sodium carbonate, raises the pH of the cake to more than pHil. This destroys virtually all pathogens in the cake. Table I summarises the maximum pH tolerance for a range of pathogens.
Table I - Maximum pH tolerances for various pathogens Pathogen Max. pH for pathogen growth Bacillus Cereus 9.3 Campy/obacterjejuni 9.5 Clostridium botu/inum 9 C/ostridiumpefringens 9 bscherichia co/i 9 Listeria monfytogenes 9.4 Sa/monella spp 9.5 Shie//a spp 9.3 Staphy/ococcus aureus 10 Vibrio cho/erae 10 Vibrio parahemo/yticus 11 Vibrio parahemo/gtica 11 Vibrio vunficus 10 Yersinia enteroco/itica 10 Sodium carbonate is a solid that dissolves in water with minimal generation of heat. As minimal heat is generated, minimal amounts of ammonia are released. This results in fertiliser with enhance N value compared to limed cake, and the working environment in the sewage works is much improved.
Addition of sodium carbonate to the sludge cake has further benefits to the sewage treatment process. Sodium carbonate will saponify fats in the sewage sludge fatty acid sodium salts which are soluble in water (crude soaps) and help to lubricate the sludge cake. This helps make the cake less viscous and much easier to handle.
Sewage comprises approximately 20g sulphur per m3., equivalent to 0.625 moles of sulphur per m3. Sodium percarbonate (2Na2CO33H2O2) yields approximately 13% of active oxygen on decomposition. In the preferred embodiment, SOOg of coated sodium percarbonate is added per m3 sludge cake, providing a three fold excess of active oxygen.
Sewage sludge cake comprises approximately 200g of fats per cubic metre. Taking the assumption that most of the fat present is present as oleic acid tryglycerides with an approximate molecular weight of 900, there are approximately 0.222 moles of fat per m3 sludge cake.
At least a three fold excess of alkali is required to saponify each ester group on the fat, this equates to 7lg of sodium carbonate. It is preferable to supply an excess of sodium carbonate. In the preferred embodiment, SOOg of sodium carbonate is added per m3 sludge cake, providing a seven fold excess of sodium carbonate.
Therefore, in a preferred embodiment, each m3 of dewatered sludge cake is treated with a mixture of 500g sodium percarbonate and 500g sodium carbonate.
The sodium percarbonate must be coated to improve stability within the sludge cake. Sodium percarbonate must be coated with compounds that are sparingly soluble in water. Coated sodium percarbonate is widely available commercially.
Suitable coating compounds include alkali metal silicates, suiphates, carbonates and hydrogen carbonates; for example magnesium silicate, magnesium sulphate, magnesium carbonate, sodium silicate, sodium sulphate, sodium carbonate, sodium hydrogen carbonate or aluminium silicate.
in the preferred embodiment granules of sodium percarbonate with several different coating thicknesses are used.
In the drawings, which illustrate preferred embodiments of the invention: Figure 1 is a schematic drawing of a sewage treatment works.
Referring to Figure 1, dewatered sewage sludge cake (1) is carried along a conveyor (2). A 1:1 mixture of coated sodium percarbonate and sodium carbonate is located in hopper (3). Sludge cake is deposited into the premixer (4) and a controlled amount of the sodium percarbonate/sodium carbonate mixture is deposited onto the sludge cake at regular intervals.
The mixture of sludge cake and sodium percarbonate and sodium carbonate is then carried along a screw conveyor (5). As the cake travels along the screw conveyer it is mixed, before the mixture is deposited into a storage or manuring container (6). The rate of addition of the sodium percarbonate/sodium carbonate mixture is controlled so that approximately every 1m3 of sludge cake is treated with approximately 1Kg of a 1:1 mixture by weight of coated sodium percarbonate:sodium carbonate.
Claims (21)
- Claims 1. A method for removing odours from effluent comprising contactingdewatered effluent with sodium percarbonate granules, wherein the granules are coated with a compound that is sparingly soluble in water.
- 2. A method as claimed in claim 1, wherein the dewatered effluent is further contacted with an alkali.
- 3. A method as claimed in claim 2, wherein the alkali is sodium carbonate.
- 4. A method as claimed in claim 3, wherein each cubic metre of effluent is contacted with an amount of coated sodium percarbonate in the range 200g to 1000g and an amount of sodium carbonate in the range 200g to l000g.
- 5. A method as claimed in claim 3, wherein each cubic metre of effluent is contacted with 500g coated sodium percarhonate and SOOg sodium carbonate.
- 6. A method as claimed in any preceding claim, wherein the effluent is sewage.
- 7. A method as claimed in any preceding claim, wherein the sodium percarbonate is coated with at least one compound selected from the group comprising: magnesium silicate; magnesium carbonate; magnesium sulphate; sodium silicate; sodium carbonate; sodium hydrogen carbonate or aluminium silicate.
- 8. A method as claimed in any preceding claim, wherein the coating amounts to 0.5 to 25 weight % of coating compound relative to sodium percarbonate.
- 9. A method as claimed in any preceding claim, wherein the sodium percarbonate is coated with a number of layers, n, wherein; when n = I the coating amounts to 0 to 1.5 weight % relative to sodium percarbonate; when n = 2 the coating amounts to 0 to 3 weight o,/ relative to sodium percarbonate; when n = 3 the coating amounts to 0 to 4.Sweight % relative to sodium percarbonate; when n = 4 the coating amounts to 0 to 6 weight % relative to sodium percarbonate; when n = 5 the coating amounts to 0 to 7. 5 weight % relative to sodium percarbonate; when n = 6 the coating amounts to 0 to 9 weight O,/ relative to sodium percarbonate; when n = 7 the coating amounts to 0 to 10.5 weight % relative to sodium percarbonate; when n = 8 the coating amounts to 0 to 12 weight % relative to sodium percarbonate; when n = 9 the coating amounts to 0 to 13.5 weight % relative to sodium percarbonate; and when n = 10 the coating amounts to 0 to 15 weight % relative to sodium percarbonate.
- 10. A method as claimed in claim 9, wherein the coated sodium percarbonate is a mixture of coated sodium percarbonate with n in the range I to 10.
- 11. A method as claimed in any preceding claim, wherein an amount of coated sodium percarbonate remains in the effluent in unreacted form for up to three months.
- 12. A method as claimed in claim 11, wherein an amoimt of coated sodium percarbonate remains in the effluent in unreacted form for up to two months.
- 13. A method as claimed in claim 11 or 12, wherein an amount of coated sodium percarbonate remains in the effluent in unreacted form for up to one month.
- 14. A method as claimed in any of claims 11 to 13, wherein an amount of coated sodium percarbonate remains in the effluent in unreacted form for up to 15 days.
- 15. A method as claimed in any of claims Ii to 14, wherein an amount of coated sodium percarbonate remains in the effluent in unreacted form for up to 10 days.
- 16. A method as claimed in any of claims 11 to 15, wherein an amount of coated sodium percarbonate remains in the effluent in unreacted form for up to 5 days.
- 17. A method as claimed in any of claims 11 to 16, wherein sodium percarbonate is a mixture of coated sodium percarbonate that remains in the effluent in unreacted form for up to 5 days; coated sodium percarbonate that remains in the effluent in unreacted form for up to 10 days; coated sodium percarbonate that remains in the effluent in unreacted form for up to days; and coated sodium percarbonate that remains in the effluent in unreacted form for more than 15 days.
- 18. A product suitable for use in the method as claimed in any of claims 3 to 17 comprising a mixture of sodium carbonate and coated sodium percarbonate.
- 19. A product as claimed in claim 18, wherein the mixture comprises sodium carbonate and coated sodium percarbonate in a ratio of 1:1 by weight.
- 20. Effluent treated according to the method claimed in any of claims I to 19.
- 21. Effluent treated with the product as claimed in claim 18 or 19.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB0508622.8A GB0508622D0 (en) | 2005-04-28 | 2005-04-28 | Method for treating effluent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0608357D0 GB0608357D0 (en) | 2006-06-07 |
| GB2426973A true GB2426973A (en) | 2006-12-13 |
Family
ID=34673984
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0508622.8A Ceased GB0508622D0 (en) | 2005-04-28 | 2005-04-28 | Method for treating effluent |
| GB0608357A Withdrawn GB2426973A (en) | 2005-04-28 | 2006-04-28 | Method of deodorising dewater effluent |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0508622.8A Ceased GB0508622D0 (en) | 2005-04-28 | 2005-04-28 | Method for treating effluent |
Country Status (2)
| Country | Link |
|---|---|
| GB (2) | GB0508622D0 (en) |
| WO (1) | WO2006114651A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009050191A2 (en) | 2007-10-15 | 2009-04-23 | Kemira Kemi Ab | Process for the production of a granule of a coated oxidizing compound such granule and uses of the granule |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110606597A (en) * | 2019-09-11 | 2019-12-24 | 崔玉祥 | Treatment method for efficiently removing COD (chemical oxygen demand) in wastewater |
| DE102019134195A1 (en) * | 2019-12-12 | 2021-06-17 | Johannes Wissing | Process and system for the treatment of olfactory contaminated substances |
| CN111253182A (en) * | 2020-01-16 | 2020-06-09 | 常州市金太阳动物保健品有限公司 | Wangcao polyoxin tablet and preparation method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1384207A (en) * | 1972-06-05 | 1975-02-19 | Fmc Corp | Odour abatement in animal wastes |
| GB1526129A (en) * | 1975-10-09 | 1978-09-27 | Tokai Electro Chemical Co | Solid-liquid separation method for organic waste sludge |
| GB1583622A (en) * | 1977-05-26 | 1981-01-28 | Degussa | Process for deodorising liquid manure and for removing noxious gases |
| JPH10118669A (en) * | 1996-10-18 | 1998-05-12 | Mitsubishi Gas Chem Co Inc | Oxidizing treatment of organic matter |
| JPH1129797A (en) * | 1997-07-11 | 1999-02-02 | Mitsubishi Gas Chem Co Inc | Peroxide-containing composition |
| WO2004094320A1 (en) * | 2003-04-23 | 2004-11-04 | Kemira Kemi Ab | Method of treating digested sludge |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62121699A (en) * | 1985-11-21 | 1987-06-02 | Nippon Peroxide Co Ltd | Method for deodorizing dehydrated cake |
| DE59301882D1 (en) * | 1992-10-16 | 1996-04-18 | Solvay Interox Gmbh | Sodium percarbonates stabilized by coating |
| DE4311944A1 (en) * | 1993-04-10 | 1994-10-13 | Degussa | Coated sodium percarbonate particles, process for their preparation and detergent, cleaning and bleaching compositions containing them |
| JPH11158016A (en) * | 1997-11-25 | 1999-06-15 | Mitsubishi Gas Chem Co Inc | Sodium percarbonate-containing composition |
| JP2001321428A (en) * | 2000-05-16 | 2001-11-20 | Mitsubishi Gas Chem Co Inc | Deodorant |
-
2005
- 2005-04-28 GB GBGB0508622.8A patent/GB0508622D0/en not_active Ceased
-
2006
- 2006-04-28 WO PCT/GB2006/050087 patent/WO2006114651A1/en active Application Filing
- 2006-04-28 GB GB0608357A patent/GB2426973A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1384207A (en) * | 1972-06-05 | 1975-02-19 | Fmc Corp | Odour abatement in animal wastes |
| GB1526129A (en) * | 1975-10-09 | 1978-09-27 | Tokai Electro Chemical Co | Solid-liquid separation method for organic waste sludge |
| GB1583622A (en) * | 1977-05-26 | 1981-01-28 | Degussa | Process for deodorising liquid manure and for removing noxious gases |
| JPH10118669A (en) * | 1996-10-18 | 1998-05-12 | Mitsubishi Gas Chem Co Inc | Oxidizing treatment of organic matter |
| JPH1129797A (en) * | 1997-07-11 | 1999-02-02 | Mitsubishi Gas Chem Co Inc | Peroxide-containing composition |
| WO2004094320A1 (en) * | 2003-04-23 | 2004-11-04 | Kemira Kemi Ab | Method of treating digested sludge |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009050191A2 (en) | 2007-10-15 | 2009-04-23 | Kemira Kemi Ab | Process for the production of a granule of a coated oxidizing compound such granule and uses of the granule |
| US8338341B2 (en) | 2007-10-15 | 2012-12-25 | Kemira Kemi Ab | Process for the production of a granule of a coated oxidizing compound such granule and uses of the granule |
| US8501670B2 (en) | 2007-10-15 | 2013-08-06 | Kemira Chemicals Inc. | Well treatment fluid compositions and methods of use that include a delayed release percarbonate formulation |
| US9150779B2 (en) | 2007-10-15 | 2015-10-06 | Kemira Chemicals Inc. | Well treatment fluid compositions and methods of use that include a delayed release percarbonate formulation |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0508622D0 (en) | 2005-06-08 |
| WO2006114651A1 (en) | 2006-11-02 |
| GB0608357D0 (en) | 2006-06-07 |
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| Date | Code | Title | Description |
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| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |