Title of Invention	"AN IMPROVED METHOD AND A DEVICE FOR SEPARATION OF FATS AND SUSPENDED SOLIDS FROM WASTEWATER"
Abstract	A biological method is devised by which fats and solids in wastewaters are separated and removed for further recovery or treatments. The process is established by mixing of the wastewaters with anaerobic sludge under biological conditions, resulting in biochemical reactions to produce metabolites including gases, and enabling separation of fats and solids from suspended and colloidal constituents which are otherwise affected the decontamination treatments, especially anaerobic and aerobic methods. In the process biologically separated fats and solids are floated and accumulated over the liquid in the system. The individually segregated fats and solids or as their combined sludge is removed at least by a device presented where sludge is allowed to drain or sucked from the top of the liquid and collected for further processing while the gas out put, if any from the system can be tapped for energy applications separately. The present invention enables simultaneously to clarify complex wastewaters by removing the fats or solids and leaving mainly the dissolved impurities for their trouble free and effective treatment further, in case required. 22

Title of Invention

"AN IMPROVED METHOD AND A DEVICE FOR SEPARATION OF FATS AND SUSPENDED SOLIDS FROM WASTEWATER"

Abstract

A biological method is devised by which fats and solids in wastewaters are separated and removed for further recovery or treatments. The process is established by mixing of the wastewaters with anaerobic sludge under biological conditions, resulting in biochemical reactions to produce metabolites including gases, and enabling separation of fats and solids from suspended and colloidal constituents which are otherwise affected the decontamination treatments, especially anaerobic and aerobic methods. In the process biologically separated fats and solids are floated and accumulated over the liquid in the system. The individually segregated fats and solids or as their combined sludge is removed at least by a device presented where sludge is allowed to drain or sucked from the top of the liquid and collected for further processing while the gas out put, if any from the system can be tapped for energy applications separately. The present invention enables simultaneously to clarify complex wastewaters by removing the fats or solids and leaving mainly the dissolved impurities for their trouble free and effective treatment further, in case required. 22

Full Text	FIELD OF THE INVENTION The present invention relates to a device and a method for separation of fats and suspended solids from wastewater. More particularly, the present invention relates to a device and a process for the easy separation and removal of fats and suspended impurities from wastewater and simultaneously or prior to removal of dissolved contaminants down stream biological processes. The present invention also relates to a system for purifying highly contaminated water which contains suspended solid impurities (TSS) and high concentrations of BOD (biochemical oxygen demand) and COD (chemical oxygen demand) as in effluents from fish processing industries, dairy industries, food processing plants, slaughter houses and also from the industrial wastewater where the fats and TSS contents are more . The method enables the efficient separation and removal of un-dissolved substances from wastewater and the treatment of wastewater by a combination of floatation and biochemical reactions. In other words, this invention relates to a device that enables both removal of suspended matters and biological degradation of impurities in wastewater. BACKGROUND OF THE INVENTION AND PRIOR ART Many industrial operations result in generation of liquid effluents containing substantial amounts of impurities, which have to be removed for meeting national and international discharge regulations. Generally several of these industrial effluents have substantial quantities of BOD present as suspended solid materials in addition to dissolved BOD. The treatment of wastewater for the removal of substances that contribute biodegradable impurities is best accomplished by biological methods such as aerobic degradation and anaerobic processes. These biological treatments are found to be faster for the removal of dissolved impurities compared to fats and suspended BOD bearing particulates (Waste treatment in the food processing industry, CRC press, Wang and Wang 2006). The BOD exerting suspended solids include, but are not limited to, partially dissolved and partially macromolecular materials, such as long-chain fatty acids, fats, vegetable oils, proteins, tallow, bacterial and yeast cells, microbial cell-walls, celluloses, hemicelluloses, starch and a mixture thereof; the suspended solids being present in emulsified, suspended or colloidal state. Effluents of this nature are discharged for example, from fish processing industries, slaughterhouses, dairies, rendering plants, oil mills, pharmaceutical and organo-. chemical plants, pulp and paper factories. The relevant organic compounds constituting biodegradable solids are generally classified as 1) Polysaccharides common among which are starch, cellulose, hemicellulose and pectins 2) Proteins and amino acids which are present as insoluble matter when coagulated by heat, acids or tannins and 3) Fats and long chain fatty acids. All these compounds are degraded and removed from the system much slowly compared to their depolymerised and dissolved monomers by microorganisms. This first step in the degradation of polymeric solids is called solubilization, which results in the formation of soluble compounds and is carried out by enzyme actions outside of the microbial cells. This is a slow process and requires sufficient microbial populations producing the enzymes and sufficient contacting time between enzymes and solids. In fact, the solubilization step is most often the rate-limiting step in the sequence of biological processes that result in mineralisation of the polluting substances. Wastewaters usually contain a mixture of biochemical contaminants with soluble and insoluble fractions. The un-dissolved biochemical contaminants in wastewater though biodegradable are the major limiting steps in both aerobic and anaerobic wastewater treatment systems. Separation of the insoluble contents such as carbohydrates, lignin, proteins, and lipids is essential for the effective decontamination, which is a statuary requirement for the protection of environment. Because of complex nature and less density differences of the insoluble fractions the removal is not easily possible in the wastewaters. The high-rate biological treatment systems including anaerobic reactors have become the economic option in the treatment of industrial effluents containing biodegradable impurities. However, most of the commercially used high-rate reactors are effective for the treatment of industrial effluent with BOD primarily in dissolved form. There are no high-rate reactors in effective use, for the treatment of wastewater containing un-dissolved BOD. There is no known teaching in prior of any special biological process for the separation and removal of he fats and solids in wastewaters that enable clarification of wastewaters suitable for their effective stabilization treatments further. Prior arts only reveal processes and methods of handling fats and solids by physical means and digesting within the system. This demands the need for an effective method, specifically developed to accomplish the primary object of this invention, i.e., the separation and removal of fats and solids from wastewater for full utilization of high-rate aerobic and anaerobic treatments. There is limited prior art to develop a biological method alone for the removal of fats and solids from effluents. Most of the developments are to stimulate treatment of un-dissolved materials along with dissolved BOD, which is considered easy and convenient because the usual methods of fats and suspended matter separation and removal from the wastewater streams are difficult. There are many reports on these aspects where efforts are made to overcome the drawbacks and interferences of fats and solids in the treatment of wastewaters (Screening Equipment" Handbook for industrial and municipal water and wastewater treatment, Second edition 1995, Tom M. Pankratz, CRC Press; Water Science and Technology, 24, 8, 87-107, 1991; Water Research 35, 3, 817-829,2001; U.S. Pat. No. 4,446,027; 5, 308,479; 5,198,113; 6,177,004; 6,136,190; 6,024,870; 5,445,740; 5,126,042; 5,232,586; 5,314,621; 4,613,434). Because of the problems and inefficacy of combined treatments there is a need for separate treatments, if possible. In this line membrane bioreactors have been tried wherein membrane modules are used for separation of solids from the liquor. These reactor systems consume large amounts of energy to drive the membrane systems. It may be noted that membrane systems separate very fine and colloidal matter including individual microorganisms in addition to larger suspended solids present in the effluents of interest. Importantly fouling of membrane is unmanageable in such wastewater systems. Thus the application of membrane systems for the treatment of complex wastewaters is inappropriate and uneconomic for the application at hand. The object of the invention is to avoid such drawbacks in wastewater treatment. The separation methods of prior art are cumbersome, elaborate and expensive. In the treatment of wastewaters several separation techniques are reported which include mechanical separation, filtration, osmosis and ultra filtration processes and flotation processes. Compared to other methods separation by floatation has many advantages for the separation and removal of fats, solids and fats containing solids from wastewaters. Fats and solids of biological origin or biodegradable are floatable under appropriate conditions and thereby removal is possible in the treatment of wastewaters. Floatation has been reported in a number of ways for the separation of fats and solids. Reference may be made to U.S. Pat. No. 5,540,836 entitled "wastewater treatment system and method"wherein, they described floatation method with dissolved air. Reference may be made to U.S. Patent No. 4,728,517 wherein , they described a method related to dewatering of sludge, particularly sludge derived from float sludge produced by dissolved air flotation, one of the techniques of air floatation's from poultry slaughtering operations. Reference may be made to U.S. Pat. No. 4,069,149 wherein, a wastewater treatment comprising separating solids from the bulk of the liquid by a gaseous floatation process, using the dissolved gas in the liquid as the source of gaseous bubbles for floatation purposes is described. Reference may be made to U. S. Patent No. 7,279,101 wherein, they described an anaerobic biological wastewater treatment system for treating wastewater containing organic contaminants including a dissolved-air flotation tank. The dissolved-air flotation tank is meant to carry out liquid-solid separation on effluent for recovering and recycling anaerobic microorganisms entrained in the effluent. The separation of microbial particles in this invention is using the principle of air floatation. Reference may be made to U. S. Patent No. 4,085,041 wherein, they described a biological oxidation and flotation apparatus for use in the treatment of sewage or other aqueous waste material by the activated sludge process. In this method oxygen containing gas bubbles of less than 500 micron size are introduced for biological treatment of the aqueous material in a tank and in the treatment suspended solid particles and flotation chamber. Reference may be made to U.S. Patent No. 5,660,718 wherein, they described a method for removing solid particles from liquids involving flotation with jet injecting air. Reference may be made to U.S. Patent No. 5,437,785 wherein, they described a method comprising an anaerobic digester, a free standing tank and a flotation cell. The gas produced during the anaerobic digestion is then compressed in the tank and mixed with water, which is further directed from the tank to the flotation cell to assist the flotation. Reference may be made to European Patent No .EP0948463 and U. S. Patent No. 6063273 wherein, they described the biological purification of wastewater use is made of a column containing a UASB reactor where a floatation apparatus is mounted on the aerator to separate biomass. Reference may be made to U.S. Patent No. 7156999 wherein, they described a method of treating animal manure yielding a final liquid fraction and solid fractions whereby the final liquid fraction has a suspended solids content of up to nearly 3 g/L through a biological passive flotation step with a polymer in a flotation unit having a hydraulic residency time (HRT) of about 4 to about 24 hours. This floatation is repeated for solid liquid separation to yield a final liquid. Reference may be made to Patent No. GB2118537 entitled "Method of concentration of biological, especially activated sludge " wherein, they described a method of concentration of sludge by adding oxygen-containing nitrogen compounds, most suitably nitrates or nitrites, in an amount of 50 to 1000 g/m under anaerobic conditions so as to form sludge flakes. Similar floatation methods are found in prior art for the separation of suspended solids from liquids where the common requirement is the supply of gas or gases from outside using specially designed systems in presence or absence of added chemicals. Introduction of air or oxygen to wastewaters is disadvantageous if further treatment is anaerobic. Usually the addition of chemicals for induction of floatation and concentration requires continuous standardization and monitoring to obtain desired results. It would be clear, that the processes disclosed above are hampered by the expense and complexity of the gas flotation process where mechanical systems involve, and need to be carried out in closed equipment when flammable gas is used. The effectiveness of this process is not known further and there is no literature on installation of many of the above processes. In the present invention generation of gases and bio-chemicals is induced and promoted in-situ for the separation of fats and solids from the wastewaters and facilitated easy removal to obtain solids and fats free liquid portion. Since it is induced to produce gases and bio-chemicals in-situ as per the requirement and conditions governed by the system itself no external standardization is needed in the present invention. Thus the method of floatation in our invention for the separation of fats and solids from wastewater is different, less cumbersome and less costly from the state of art because of the elimination of the steps such as chemical addition and forcing air, oxygen or gases. Furthermore, the avoidance of air and oxygen introduction eliminates the chance of effluent oxygenation, which hampers anaerobic process, if required in the further treatments. OBJECTIVES OF THE INVENTION The main object of the present invention is to provide a device for the removal of insoluble matter such as fats and biodegradable solids from wastewater for its effective biological treatment. Another object of the present invention is to provide a method for the easy separation and removal of fats and suspended impurities from wastewater. Another object of the present invention is to provide a method for anaerobic treatment of complex wastewater containing considerable amount of insoluble matter such as fats and biodegradable solids. Another object of the present invention is to provide a device and a method for anaerobic treatment of complex wastewater containing considerable amount of insoluble matter such as fats and biodegradable solids. Yet another object of the present invention is to remove water immiscible pollutants from the wastewater for faster and improved biological treatment. Still another object of the present invention is substantial reduction in the size of wastewater treatment plants for the removal of fats and solids containing wastewaters to reduce the cost of wastewater treatment. Yet another object of the present invention is to avoid addition of chemicals or gases in the floatation techniques and hence reduces the extra treatment costs required to maintain chemicals or gas storage and handling equipment. SUMMARY OF INVENTION Accordingly, the invention provides a device for treating wastewater containing fats and solids comprising: a fats and solids separator which consist of first nozzle (507) for pumping in the wastewater containing fats and solids, a second nozzle (508) in the bottom for pumping in liquid containing wastewater and anaerobic sludge, a third nozzle (509) for letting out clear liquid free of fats and solids, a fourth nozzle (513) for removing fats and solids and a fifth nozzle (510) for collecting gas; in combination with an upflow anaerobic sludge bed reactor having at least one liquid column (518) containing anaerobic sludge bed(516) ,a minimum of one inlet (522) arranged to feed wastewater to the liquid column, two outlets for removing clear wastewater, solids and fats and a nozzle (515) is located at the bottom. The invention further provides a method for treating wastewater containing fats and solids by floatation comprising the steps of: a) introducing the wastewater containing fats and solids to a liquid column containing anaerobic sludge; b) mixing the content of step (a), wherein biological activity of the anaerobic sludge produces tiny bubbles of gases allowing the immiscible fats and solids in the wastewater to float; c) removing the floating material as obtained from step (b) from the liquid to obtain wastewater free of suspended solids and fats ; d) further processing the wastewater free of suspended solids and fats as obtained from step (c) in a biological treatment system wherein anaerobic processing is carried out to remove contaminants from the wastewater. In one embodiment of the invention, a nozzle (515) is located at the bottom of anaerobic sludge bed reactor through which the clarified wastewater from the fats and solids separation device is pumped in. In another embodiment of the invention, a lid (520) is fixed on the collar (519) with a gas collector (529) on the top of the anaerobic sludge bed reactor. In another embodiment of the invention, the said device automatically releases the gas through the outlet (525) of the column while removing the buoyant fats and solids. In another embodiment of the invention, the said wastewater contain miscible and/or immiscible fats and solids in colloidal suspension which are not settleable. In another embodiment of the invention, the wastewater is introduced to the liquid column at a temperature in the range of 5 °C to 55°C and pH in the range of 3.0 to 8.0. In another embodiment of the invention, the wastewater introduced to liquid column containing anaerobic sludge results in biochemical changes in the liquid column. In another embodiment of the invention, the resulting biochemical reactions generates short chain fatty acids that include acetic acid, and releases carbon dioxide, methane or hydrogen sulphide or a mixture thereof in the said liquid column. In another embodiment of the invention, the liquid column containing wastewater is having facility to mix the content using mechanical stirrer or by circulation of liquid within. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIGURE. 1 scheme illustrating steps of a method of fats and solids removal from wastewater and further anaerobic treatment of wastewater containing dissolved impurities in accordance with the present invention. FIGURE. 2 schematic representation of one embodiment of a fats and solids separation, and removal system in accordance with the present invention. FIGURE. 3 anaerobic treatment of clarified wastewater in accordance with the present invention. FIGURE. 4 a photographic representation of the entire system wherein the process of the present invention was carried out. FIGURE. 5 a photographic representation of one embodiment of a fats and solids separation, and removal system in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention reveals a device and a method to remove fats and solids from industrial wastewater such as fish processing, slaughterhouse, dairy etc. makes their treatment more effective, fast and trouble free during the downstream treatments like anaerobic, aerobic, etc. This method facilitates floatation, separation, accumulation and collection of fats and solids from wastewater thereby reduces the time of biological treatment, increases the level of pollutants removal and reduces the cost wastewater treatment. This method also enables clarification of wastewater from immiscible contaminants for improving biodegradation of pollutants in wastewater in the subsequent treatments. The present invention permits the process of wastewater treatment stable and trouble free by using a device for the removal of fats and solids which are otherwise resistant to degradation by biological means when compared to its dissolved biodegradable pollutants. The removal of fats and solids by this method and device helps to deter their interference on the activities of anaerobic sludge which is involved in the biodegradation of pollutants to biogas or carbon dioxide in wastewater treatment. The entire process was carried out in the biological conditions and free of oxygen in case the subsequent courses of purification involve anaerobic processing such as biomethanation and sulphidogenesis. In this method the wastewater is loaded to a column or more than one of the choices of preference, but the liquid height is more than 2 feet followed by a settling treatment where heavy and fast settling materials such as stones, sands, metals (further only non-biodegradable) and subjected to actions. It has been observed by the inventors that the biological activity of the sludge mainly at the bottom of the column for fat and solids separation produces tiny bubbles of gases that triggers buoyancy of immiscible materials in the wastewater and this method of fats and solids removal is considerably activated by gentle agitation of the sludge at the bottom of the column using a mechanical stirrer or through pumping of the clarified wastewater or liquid which is being generated in the process and can be drawn from the column without disturbing the buoyant fats and solids layer at the top. It was also observed that the gentle mixing of the sludge at the bottom of the column enables incessant activity of the microbial community and thereby separation of solids particles was more effective from the wastewater. The generally found immiscible wastewater contaminants such as fats at varying concentrations from 0.05 - 3.0 g/1 and bio-solids of different particle sizes from few microns to 0.8 mm depending on the kind and nature of industries, are clearly separated from the liquid and accumulated above the liquid level by this process. In this invention the transfer of separated and accumulated impurities from top of the liquid in the column and its collection are effectively done by a device of attachment consisting of a narrow side armed tube or its multiples on the top of the separation column, which also facilitates collection of the gas produced from the column along while discharging and collecting the separated fats and solids through the side arm tube automatically. The extreme pH like less than 3.0 or above 8.0 and the temperature less than 5 °C and above 55 °C of the regime in the process lead to inactivation of the microorganisms involved in the degradation and methanogenic reactions. The exposure to oxygen or air containing oxygen in this process of fats and solids removal causes oxygenation of the clarified liquid, which is undesirable when the subsequent treatment method is anaerobic and leading to methane production or sulphidogensis. In the present invention it has been observed that by this method separation and removal of particles ranging from few microns to larger 0.8 mm sizes that are otherwise difficult to be removed from the liquid by other known techniques like settling and floatation was easily done continuously. It was also noted that solids at different levels ranging from few milligrams to many grams per liter, usually discharged in the complex wastewaters and are slowly biodegraded by the usual methods gets separated and removed by this method fairly rapid in the presence and absence of fats. The major advantages observed in this method for wastewater treatment are time and cost savings, efficacy in further treatment processes. Value recovery during wastewater treatments from both dissolved impurities, and immiscible fats and solids collected which is otherwise degraded through expensive and elaborate methods, is an added advantage of this invention. In the present invention it was also observed that otherwise unsettleable bigger organic particles above the said sizes were also found buoyant and enables easy removal from wastewater. The presence of fats while separating along with solids was changed to sticky sludge that affected the easy and smooth removal from the top of the liquid as experienced in the treatment of wastewater from fish processing industry units. Breaking of the clumps through conventional agitation techniques eliminates the clogging resulting from the aggregation of sludge in the process. This invention enables easier treatment of wastewater from fish processing, slaughterhouse, diary, etc. by the removal of fat, which is not only resistant to biodegradation but seriously, interferes also with microbial cells. Effective treatment of wastewater in anaerobic system is affected by the fat constituents more than 100 mg /litre which would be present invariably in most of the industrial wastewaters because of the aforesaid reasons. It was noticed that after the removal of solids and fats by this method and device biological treatment of wastewater becomes effective and less cumbersome as there is no need to provide long retention time for waiting to biodegrade both fat and solids compared to dissolved biodegradable contaminants. FIGURE 1 wherein the various steps of the present invention are carried out, the wastewater containing fats and solids is prepared in a plastic tank 501, wastewater from the plastic tank is pumped to a glass fats, solids and gas separator 502, the fats and solids separated in the glass device is removed by a device and collected to a glass or plastic container 503, the wastewater after separation of fats and solids in the glass separator is passed to an upflow anaerobic sludge bed anaerobic reactor 504, the anaerobically treated effluent from upflow anaerobic sludge bed anaerobic reactor is collected in a plastic tank 505 and the biogas produced during the treatments is measured in a meter 506. FIGURE 2, the fats and solids separator is made up of glass with 3 nozzles, one for pumping in the fats & solids containing wastewater 507 another in the bottom 508 for pumping in waste water or draining of sludge 511 and liquid, another for letting out the clear liquid free of fats& solids 509. On top of the fats & solids separator a device to collect fats, solids and gas fabricated in glass 512 is fixed using a rubber cork in the real experimental set up unlike shown in the figure 2 as a single unit. The fabricated set up of the fats, solids and gas separation and collection device is further shown in the FIGURE 4. The device to remove fats, solids and gas has two nozzles, one 513 for removing fats & solids which is collected in a plastic or glass container 514 and the second 510 for collecting gas. FIGURE 3, there is shown a diagram wherein illustration of anaerobic treatment of clarified wastewater in an upflow anaerobic sludge bed anaerobic (UASB) reactor. This reactor vessel has three major components, a conical bottom fabricated in stainless steel, which has a nozzle 515 through which the clarified wastewater from the fats and solids separation device Figure 2 is pumped to the UASB. Above this conical portion a tall glass column 518 containing anaerobic liquid 517, and has stainless steel collar 519 on its top. The stainless steel collar is provided with 2 nozzles, 522 for circulating liquid inside and 528 for removing liquid 521 after anaerobic treatment by overflow 524 collecting chamber 527. A lid 520 is fixed on the collar with a gas collector 529 and nozzle on the top 525 for releasing gas from the gas collector. Anaerobic sludge bed 516 in the reactor converts dissolved impurities in the wastewater to biogas, a mixture of carbon dioxide and methane which is the dominant gas. The biogas produced in the UASB is collected on the top 526 of the gas collector. FIGURE 4, a photographic realization of the complete system wherein the process of the present invention is carried out, having fats, solids and gas separation and collection parts and followed by an anaerobic treatment system for the treatment of clarified wastewater from the device described in figure 2. FIGURE 5 is a photographic representation of one embodiment of a fats, solids and gas separation, and collection system in accordance with the present invention illustrated in figure 2. According to the preferred embodiment of the invention, fat concentration in the range of 0.1 to 3.0 g/liter in wastewater from the sources such as fish processing, dairy, slaughterhouse, etc. is treated with a liquor containing anaerobic sludge in a liquid column under anoxic condition which enables separation and buoyancy of fat alone or associated with solids above the liquid in the column by operating at biological conditions of temperature 5°C to 55°C and pH between 3.0 to 8.0, thereby generates a fat free effluent. The resulting fat removed wastewater containing mainly the dissolved impurities such as volatile fatty acids, amino acids, proteins and other soluble organic compounds is further sent to a biological treatment system where aerobic or anaerobic processing or both are applied to remove the contaminants from the water. In yet another preferred embodiment of the invention, concentration of suspended solids in the range of 0.05 gm to 3.0 g/liter having the particles of size ranging from 0.01 to 0.5 mm or is brought to the particles size ranging from 0.01 to 0.8 mm for resulting easy and faster separation of solids from the sources of wastewater such as fish processing, food processing, pulping, slaughterhouse, etc. followed by treating with a liquor containing anaerobic sludge in a liquid column under anoxic condition which enables separation and buoyancy of particles above the liquid in the column by operating at biological conditions of temperature 5°C to 55°C and pH between 3.0 to 8.0, thereby generates a clear effluent free of suspended particles. The resulting clear effluent containing dissolved impurities such as volatile fatty acids, amino acids, proteins and soluble organic compounds is further sent to a biological treatment system where aerobic or anaerobic processing or both are used to remove the contaminants from the water. According to a feature of the present invention the fats and suspended solids in wastewaters separated by the biological reactions above the liquid are collected, resulting a concentrated liquid or slurry with fats and solids up to 10-25% for further processing to recover fat and/or generate methane energy in an anaerobic digestion process. According to a feature of the present invention the treatment of resulting volatile fatty acid and dissolved impurities is further converted to biogas and removed from liquor as biogas by the process of methanogenesis, enabling faster and effective purification of wastewater from industries such as fish processing, slaughter house, food processing, diary, pulping, etc. This invention also features treatment of said clear effluent further to fats and solids removal under aerobic treatment by providing oxygen or air containing oxygen or oxygen bearing chemical compounds like hydrogen peroxide whereby the impurities are oxidized and removed by a population of aerobic sludge to meet discharge standards of wastewater. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. Example 1 Fish processing effluent was prepared in the laboratory bearing Chemical Oxygen Demand (COD) in the range of 1039 to 1854 mg/1. The wastewater had pH of 6.2 to 7.4, total suspended solids concentration in the range of 422-759 mg/1 and in which the size of particles were between 20 to 600 um, and concentration of fats was ranged between 521-895 mg/1. This wastewater was fed to the fats and solids separation system (process flow diagram) made up of glass column and working volume 61itres, at the rate of 28.61itres/day with a total COD loading of 5 to 8.8 kg/m3/day. The fats and solids separation system operated was a cylindrical glass column having the size, 70 cm length X 11.25 cm i.d. fitted with a side armed (side arm of 20 cm length X 10 mm i.d. fitted at 10 cm above 70 cm level) glass tube of total length 29 cm andlO mm i.d.) on the top, two side ports, one at the level of 20 cm and the second at 40 cm height, and a bottom port, of 3.82 cm diameter each. The wastewater kept under mixing in a reservoir was pumped through one of the side inlets of the said fats and solids separation system and the outlet for the clear liquid was drained from the second side port. Mixing of liquid in the fats & solids separation system was affected by pumping back liquid free of solids and fats to the bottom of the separation system. The new process separated fats & solids of the said wastewater on introduction to the separation system, accumulated above the clear liquid level. The new method also enabled collection of fats & solids free liquid through the side arm of the system while the top end of the tube facilitated release of gas. The clarified liquid of pH between 6.3 to 7.6 was allowed to pass through the side port other than the wastewater feed port of the fats and solids separation column using the connected rubber tubes of 10 mm i.d., that was partly cycled through the bottom port of the fats and solids separation column and the remaining liquid was treated by pumping through a hybrid anaerobic glass reactor of 9.0 litre working volume, having anaerobic expanded sludge of 1.5 litre at the bottom, floating pall rings on top with retained biomass. Anaerobic biomass of microorganisms capable of degrading waste fish materials and converting to biogas (> 60% methane) was seeded to the fats & solids separation column and anaerobic reactor from a wastewater dumping pond of a fish processing unit and allowed to grow by operating for more than 6 months. The anaerobic reactor liquor pH was in between 5.8 to 7.8 and mostly in the near neutral range of 6.6 to 7.5. The entire experimentation was conducted at the temperature between 18° and 35° Celsius. Biogas from the anaerobic reactor and fats & solids separation systems were metered in a gas flow meter connected to the systems through a rubber tube of 10 mm i.d. Biogas produced was in the range of 2.8 - 3.2 liters/day. Analytical data of the wastewater from the fats & solids separation system and anaerobic treatment is presented in Table 1. Table 1 .Characteristics of fish processing wastewater upon fats and solids separation and anaerobic treatment at hydraulic loading rate of 28.61itres/day (13.6 cubic metre/m3day"1) in the fats and solids separation. (Table Removed) Example 2 Effluent was prepared in the laboratory resembling fish processing wastewater bearing Chemical Oxygen Demand (COD) in the range of 990- 3882 mg/1. The simulated fish processing wastewater had pH of 6.2 to 7.4, total suspended solids concentration in the range of 300-3450 mg/1 and in which the particles sized between 20 to 600 urn, and fats concentration ranged between 248- 2438 mg/1. This wastewater was fed to the fats and solids separation system and working volume 6 liters at the rate of 19.8 liters/day with a total COD loading of 3.5 to 12.8kg/m3/day. The fats and solids separation system operated was a cylindrical glass column having the size, 70.5 cm length xl 1.45 cm diameter fitted with a side armed (20 cm length xlO mm i.d.) glass tube (29 cm length xlO mm i.d.) on the top , two side ports and a bottom port of 3.82 cm diameter each. The wastewater inlet to the said separation system was provided from a side port and outlet from another side port. The new process separated fats and solids of the said wastewater on introduction to the separation system, accumulated above the water level and collected through the side arm while the top end of the tube facilitated release of gas. The clarified liquid of pH between 6.3 to 7.6 was allowed to pass through the side port other than the wastewater feed port of the fats and solids separation column using the connected rubber tubes of 10 mm i.d., that was partly cycled through the bottom port of the fats and solids separation column and the remaining liquid was treated by pumping through a hybrid anaerobic glass reactor of 9.0 liter working volume, having anaerobic expanded sludge of 1.5 liters at the bottom, floating pall rings on top with retained biomass. Anaerobic biomass of microorganisms capable of degrading waste fish materials and converting to biogas (> 60% methane) was seeded to the fats & solids separation column and anaerobic reactor from a wastewater dumping pond of a fish processing unit and allowed to grow by operating for more than 6 months. The anaerobic reactor liquor pH was in between 5.8 to 7.8 and mostly in the near neutral range of 6.6 to 7.5. The entire experimentation was conducted at the temperature between 18° and 35° Celsius. Biogas from the anaerobic reactor and fats & solids separation systems were metered in a gas flow meter connected to the systems. Biogas produced was in the range of 2.5 - 3.5 liters/day. Analytical data of the wastewater from the fats & solids separation system and anaerobic treatment is presented in Table 2. Table 2. Characteristics of fish processing wastewater upon fats and solids separation and anaerobic treatment at hydraulic loading rate of 19.8 litres/day (6.5 cubic metre/m3day"1) in the fats and solids separation. (Table Removed) THE MAIN ADVANTAGES OF THE PRESENT INVENTION: 1. Avoids addition of chemicals or gases unlike in the prior arts of floatation techniques and hence the innovation reduces the extra treatment costs required to maintain, chemicals or gas storage and handling equipment 2. Substantial reduction in the size of wastewater treatment plants for the removal of fats and solids containing wastewaters also reduces the costs of wastewater treatment further down. 3. Recovery of the fats from wastewaters becomes simple and efficient 4. The present invention is more efficient and less time consuming for the treatment of wastewater containing fats and other solids 5. Can be retrofitted in the existing industrial wastewater treatment plants of various sizes and capacities . 6. Entire process and operation are environmental friendly. 7. Eliminates interferences in the treatment of wastewaters containing dissolved BOD. We claim: 1. A device for treating wastewater containing fats and solids comprising: a fats and solids separator which consist of first nozzle (507) for pumping in the wastewater containing fats and solids, a second nozzle (508) in the bottom for pumping in liquid containing wastewater and anaerobic sludge, a third nozzle (509) for letting out clear liquid free of fats and solids, a fourth nozzle (513) for removing fats and solids and a fifth nozzle (510) for collecting gas; in combination with an upflow anaerobic sludge bed reactor having at least one liquid column (518) containing anaerobic sludge bed(516) ,a minimum of one inlet (522) arranged to feed wastewater to the liquid column, two outlets for removing clear wastewater, solids and fats and a nozzle (515) is located at the bottom. * 2. The device as claimed in claiml, wherein a nozzle (515) is located at the bottom of anaerobic sludge bed reactor through which the clarified wastewater from the fats and solids separation device is pumped in. 3. The device as claimed in claiml, wherein a lid (520) is fixed on the collar (519) with a gas collector (529) on the top of the anaerobic sludge bed reactor. 4. The device as claimed in claiml, wherein the said device automatically releases the gas through the outlet (525) of the column while removing the buoyant fats and solids. 5. A method for treating wastewater containing fats and solids by floatation comprising the steps of: a) introducing the wastewater containing fats and solids to a liquid column containing anaerobic sludge; b) mixing the content of step (a), wherein biological activity of the anaerobic sludge produces tiny bubbles of gases allowing the immiscible fats and solids in the wastewater to float; c) removing the floating material as obtained from step (b) from the liquid to obtain wastewater free of suspended solids and fats ; d) further processing the wastewater free of suspended solids and fats as obtained from step (c) in a biological treatment system wherein anaerobic processing is carried out to remove contaminants from the wastewater. 6. The method as claimed in claim 5, wherein the said wastewater contain miscible and/or immiscible fats and solids in colloidal suspension which are not settleable. 7. The method as claimed in claim 5, wherein the wastewater is introduced to the liquid column at a temperature in the range of 5 °C to 55°C and pH in the range of 3.0 to 8.0. 8. The method as claimed in claim 5, wherein the wastewater introduced to liquid column containing anaerobic sludge results in biochemical changes in the liquid column. 9. The method as claimed in claim 7, wherein the resulting biochemical reactions generates short chain fatty acids that include acetic acid, and releases carbon dioxide, methane or hydrogen sulphide or a mixture thereof in the said liquid column. 10. The method as claimed in claim 5, wherein the liquid column containing wastewater is having facility to mix the content using mechanical stirrer or by circulation of liquid within. 11. A device and a method for treating wastewater containing fats and solids substantially as herein described with reference to the example and drawings accompanying this specification.

Full Text

FIELD OF THE INVENTION
The present invention relates to a device and a method for separation of fats and suspended solids from wastewater. More particularly, the present invention relates to a device and a process for the easy separation and removal of fats and suspended impurities from wastewater and simultaneously or prior to removal of dissolved contaminants down stream biological processes.
The present invention also relates to a system for purifying highly contaminated water which contains suspended solid impurities (TSS) and high concentrations of BOD (biochemical oxygen demand) and COD (chemical oxygen demand) as in effluents from fish processing industries, dairy industries, food processing plants, slaughter houses and also from the industrial wastewater where the fats and TSS contents are more . The method enables the efficient separation and removal of un-dissolved substances from wastewater and the treatment of wastewater by a combination of floatation and biochemical reactions. In other words, this invention relates to a device that enables both removal of suspended matters and biological degradation of impurities in wastewater.
BACKGROUND OF THE INVENTION AND PRIOR ART
Many industrial operations result in generation of liquid effluents containing substantial amounts of impurities, which have to be removed for meeting national and international discharge regulations. Generally several of these industrial effluents have substantial quantities of BOD present as suspended solid materials in addition to dissolved BOD. The treatment of wastewater for the removal of substances that contribute biodegradable impurities is best accomplished by biological methods such as aerobic degradation and anaerobic processes. These biological treatments are found to be faster for the removal of dissolved impurities compared to fats and suspended BOD bearing particulates (Waste treatment in the food processing industry, CRC press, Wang and Wang 2006).
The BOD exerting suspended solids include, but are not limited to, partially dissolved and partially macromolecular materials, such as long-chain fatty acids, fats, vegetable oils,

proteins, tallow, bacterial and yeast cells, microbial cell-walls, celluloses, hemicelluloses, starch and a mixture thereof; the suspended solids being present in emulsified, suspended or colloidal state. Effluents of this nature are discharged for example, from fish processing industries, slaughterhouses, dairies, rendering plants, oil mills, pharmaceutical and organo-. chemical plants, pulp and paper factories.
The relevant organic compounds constituting biodegradable solids are generally classified as 1) Polysaccharides common among which are starch, cellulose, hemicellulose and pectins 2) Proteins and amino acids which are present as insoluble matter when coagulated by heat, acids or tannins and 3) Fats and long chain fatty acids. All these compounds are degraded and removed from the system much slowly compared to their depolymerised and dissolved monomers by microorganisms. This first step in the degradation of polymeric solids is called solubilization, which results in the formation of soluble compounds and is carried out by enzyme actions outside of the microbial cells. This is a slow process and requires sufficient microbial populations producing the enzymes and sufficient contacting time between enzymes and solids. In fact, the solubilization step is most often the rate-limiting step in the sequence of biological processes that result in mineralisation of the polluting substances.
Wastewaters usually contain a mixture of biochemical contaminants with soluble and insoluble fractions. The un-dissolved biochemical contaminants in wastewater though biodegradable are the major limiting steps in both aerobic and anaerobic wastewater treatment systems. Separation of the insoluble contents such as carbohydrates, lignin, proteins, and lipids is essential for the effective decontamination, which is a statuary requirement for the protection of environment. Because of complex nature and less density differences of the insoluble fractions the removal is not easily possible in the wastewaters. The high-rate biological treatment systems including anaerobic reactors have become the economic option in the treatment of industrial effluents containing biodegradable impurities. However, most of the commercially used high-rate reactors are effective for the treatment of industrial effluent with BOD primarily in dissolved form. There are no high-rate reactors in effective use, for the treatment of wastewater containing un-dissolved BOD. There is no known teaching in prior of any special biological process for the separation and removal of

he fats and solids in wastewaters that enable clarification of wastewaters suitable for their effective stabilization treatments further. Prior arts only reveal processes and methods of handling fats and solids by physical means and digesting within the system. This demands the need for an effective method, specifically developed to accomplish the primary object of this invention, i.e., the separation and removal of fats and solids from wastewater for full utilization of high-rate aerobic and anaerobic treatments.
There is limited prior art to develop a biological method alone for the removal of fats and solids from effluents. Most of the developments are to stimulate treatment of un-dissolved materials along with dissolved BOD, which is considered easy and convenient because the usual methods of fats and suspended matter separation and removal from the wastewater streams are difficult. There are many reports on these aspects where efforts are made to overcome the drawbacks and interferences of fats and solids in the treatment of wastewaters (Screening Equipment" Handbook for industrial and municipal water and wastewater treatment, Second edition 1995, Tom M. Pankratz, CRC Press; Water Science and Technology, 24, 8, 87-107, 1991; Water Research 35, 3, 817-829,2001; U.S. Pat. No. 4,446,027; 5, 308,479; 5,198,113; 6,177,004; 6,136,190; 6,024,870; 5,445,740; 5,126,042; 5,232,586; 5,314,621; 4,613,434). Because of the problems and inefficacy of combined treatments there is a need for separate treatments, if possible. In this line membrane bioreactors have been tried wherein membrane modules are used for separation of solids from the liquor. These reactor systems consume large amounts of energy to drive the membrane systems. It may be noted that membrane systems separate very fine and colloidal matter including individual microorganisms in addition to larger suspended solids present in the effluents of interest. Importantly fouling of membrane is unmanageable in such wastewater systems. Thus the application of membrane systems for the treatment of complex wastewaters is inappropriate and uneconomic for the application at hand. The object of the invention is to avoid such drawbacks in wastewater treatment.
The separation methods of prior art are cumbersome, elaborate and expensive. In the treatment of wastewaters several separation techniques are reported which include mechanical separation, filtration, osmosis and ultra filtration processes and flotation processes. Compared to other methods separation by floatation has many advantages for the separation and removal

of fats, solids and fats containing solids from wastewaters. Fats and solids of biological origin or biodegradable are floatable under appropriate conditions and thereby removal is possible in the treatment of wastewaters. Floatation has been reported in a number of ways for the separation of fats and solids.
Reference may be made to U.S. Pat. No. 5,540,836 entitled "wastewater treatment system and method"wherein, they described floatation method with dissolved air.
Reference may be made to U.S. Patent No. 4,728,517 wherein , they described a method related to dewatering of sludge, particularly sludge derived from float sludge produced by dissolved air flotation, one of the techniques of air floatation's from poultry slaughtering operations.
Reference may be made to U.S. Pat. No. 4,069,149 wherein, a wastewater treatment comprising separating solids from the bulk of the liquid by a gaseous floatation process, using the dissolved gas in the liquid as the source of gaseous bubbles for floatation purposes is described.
Reference may be made to U. S. Patent No. 7,279,101 wherein, they described an anaerobic biological wastewater treatment system for treating wastewater containing organic contaminants including a dissolved-air flotation tank. The dissolved-air flotation tank is meant to carry out liquid-solid separation on effluent for recovering and recycling anaerobic microorganisms entrained in the effluent. The separation of microbial particles in this invention is using the principle of air floatation.
Reference may be made to U. S. Patent No. 4,085,041 wherein, they described a biological oxidation and flotation apparatus for use in the treatment of sewage or other aqueous waste material by the activated sludge process. In this method oxygen containing gas bubbles of less than 500 micron size are introduced for biological treatment of the aqueous material in a tank and in the treatment suspended solid particles and flotation chamber.

Reference may be made to U.S. Patent No. 5,660,718 wherein, they described a method for removing solid particles from liquids involving flotation with jet injecting air.
Reference may be made to U.S. Patent No. 5,437,785 wherein, they described a method comprising an anaerobic digester, a free standing tank and a flotation cell. The gas produced during the anaerobic digestion is then compressed in the tank and mixed with water, which is further directed from the tank to the flotation cell to assist the flotation.
Reference may be made to European Patent No .EP0948463 and U. S. Patent No. 6063273 wherein, they described the biological purification of wastewater use is made of a column containing a UASB reactor where a floatation apparatus is mounted on the aerator to separate biomass.
Reference may be made to U.S. Patent No. 7156999 wherein, they described a method of treating animal manure yielding a final liquid fraction and solid fractions whereby the final liquid fraction has a suspended solids content of up to nearly 3 g/L through a biological passive flotation step with a polymer in a flotation unit having a hydraulic residency time (HRT) of about 4 to about 24 hours. This floatation is repeated for solid liquid separation to yield a final liquid.
Reference may be made to Patent No. GB2118537 entitled "Method of concentration of biological, especially activated sludge " wherein, they described a method of concentration of sludge by adding oxygen-containing nitrogen compounds, most suitably nitrates or nitrites, in an amount of 50 to 1000 g/m under anaerobic conditions so as to form sludge flakes.
Similar floatation methods are found in prior art for the separation of suspended solids from liquids where the common requirement is the supply of gas or gases from outside using specially designed systems in presence or absence of added chemicals. Introduction of air or oxygen to wastewaters is disadvantageous if further treatment is anaerobic.

Usually the addition of chemicals for induction of floatation and concentration requires continuous standardization and monitoring to obtain desired results. It would be clear, that the processes disclosed above are hampered by the expense and complexity of the gas flotation process where mechanical systems involve, and need to be carried out in closed equipment when flammable gas is used. The effectiveness of this process is not known further and there is no literature on installation of many of the above processes.
In the present invention generation of gases and bio-chemicals is induced and promoted in-situ for the separation of fats and solids from the wastewaters and facilitated easy removal to obtain solids and fats free liquid portion. Since it is induced to produce gases and bio-chemicals in-situ as per the requirement and conditions governed by the system itself no external standardization is needed in the present invention. Thus the method of floatation in our invention for the separation of fats and solids from wastewater is different, less cumbersome and less costly from the state of art because of the elimination of the steps such as chemical addition and forcing air, oxygen or gases. Furthermore, the avoidance of air and oxygen introduction eliminates the chance of effluent oxygenation, which hampers anaerobic process, if required in the further treatments.
OBJECTIVES OF THE INVENTION
The main object of the present invention is to provide a device for the removal of insoluble
matter such as fats and biodegradable solids from wastewater for its effective biological
treatment.
Another object of the present invention is to provide a method for the easy separation and
removal of fats and suspended impurities from wastewater.
Another object of the present invention is to provide a method for anaerobic treatment of complex wastewater containing considerable amount of insoluble matter such as fats and biodegradable solids.

Another object of the present invention is to provide a device and a method for anaerobic treatment of complex wastewater containing considerable amount of insoluble matter such as fats and biodegradable solids.
Yet another object of the present invention is to remove water immiscible pollutants from the wastewater for faster and improved biological treatment.
Still another object of the present invention is substantial reduction in the size of wastewater treatment plants for the removal of fats and solids containing wastewaters to reduce the cost of wastewater treatment.
Yet another object of the present invention is to avoid addition of chemicals or gases in the floatation techniques and hence reduces the extra treatment costs required to maintain chemicals or gas storage and handling equipment.
SUMMARY OF INVENTION
Accordingly, the invention provides a device for treating wastewater containing fats and
solids comprising:
a fats and solids separator which consist of first nozzle (507) for pumping in the wastewater
containing fats and solids, a second nozzle (508) in the bottom for pumping in liquid
containing wastewater and anaerobic sludge, a third nozzle (509) for letting out clear liquid
free of fats and solids, a fourth nozzle (513) for removing fats and solids and a fifth nozzle
(510) for collecting gas;
in combination with an upflow anaerobic sludge bed reactor having at least one liquid column
(518) containing anaerobic sludge bed(516) ,a minimum of one inlet (522) arranged to feed
wastewater to the liquid column, two outlets for removing clear wastewater, solids and fats
and a nozzle (515) is located at the bottom.

The invention further provides a method for treating wastewater containing fats and solids by floatation comprising the steps of:
a) introducing the wastewater containing fats and solids to a liquid column containing
anaerobic sludge;
b) mixing the content of step (a), wherein biological activity of the anaerobic sludge
produces tiny bubbles of gases allowing the immiscible fats and solids in the
wastewater to float;
c) removing the floating material as obtained from step (b) from the liquid to obtain
wastewater free of suspended solids and fats ;
d) further processing the wastewater free of suspended solids and fats as obtained
from step (c) in a biological treatment system wherein anaerobic processing is
carried out to remove contaminants from the wastewater.
In one embodiment of the invention, a nozzle (515) is located at the bottom of anaerobic sludge bed reactor through which the clarified wastewater from the fats and solids separation device is pumped in.
In another embodiment of the invention, a lid (520) is fixed on the collar (519) with a gas collector (529) on the top of the anaerobic sludge bed reactor.
In another embodiment of the invention, the said device automatically releases the gas through the outlet (525) of the column while removing the buoyant fats and solids.
In another embodiment of the invention, the said wastewater contain miscible and/or immiscible fats and solids in colloidal suspension which are not settleable.
In another embodiment of the invention, the wastewater is introduced to the liquid column at a temperature in the range of 5 °C to 55°C and pH in the range of 3.0 to 8.0.

In another embodiment of the invention, the wastewater introduced to liquid column containing anaerobic sludge results in biochemical changes in the liquid column.
In another embodiment of the invention, the resulting biochemical reactions generates short chain fatty acids that include acetic acid, and releases carbon dioxide, methane or hydrogen sulphide or a mixture thereof in the said liquid column.
In another embodiment of the invention, the liquid column containing wastewater is having facility to mix the content using mechanical stirrer or by circulation of liquid within.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
FIGURE. 1 scheme illustrating steps of a method of fats and solids removal from wastewater and further anaerobic treatment of wastewater containing dissolved impurities in accordance with the present invention.
FIGURE. 2 schematic representation of one embodiment of a fats and solids separation, and removal system in accordance with the present invention.
FIGURE. 3 anaerobic treatment of clarified wastewater in accordance with the present invention.
FIGURE. 4 a photographic representation of the entire system wherein the process of the present invention was carried out.
FIGURE. 5 a photographic representation of one embodiment of a fats and solids separation, and removal system in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention reveals a device and a method to remove fats and solids from industrial wastewater such as fish processing, slaughterhouse, dairy etc. makes their treatment more effective, fast and trouble free during the downstream treatments like anaerobic, aerobic, etc.

This method facilitates floatation, separation, accumulation and collection of fats and solids from wastewater thereby reduces the time of biological treatment, increases the level of pollutants removal and reduces the cost wastewater treatment. This method also enables clarification of wastewater from immiscible contaminants for improving biodegradation of pollutants in wastewater in the subsequent treatments. The present invention permits the process of wastewater treatment stable and trouble free by using a device for the removal of fats and solids which are otherwise resistant to degradation by biological means when compared to its dissolved biodegradable pollutants. The removal of fats and solids by this method and device helps to deter their interference on the activities of anaerobic sludge which is involved in the biodegradation of pollutants to biogas or carbon dioxide in wastewater treatment.
The entire process was carried out in the biological conditions and free of oxygen in case the subsequent courses of purification involve anaerobic processing such as biomethanation and sulphidogenesis. In this method the wastewater is loaded to a column or more than one of the choices of preference, but the liquid height is more than 2 feet followed by a settling treatment where heavy and fast settling materials such as stones, sands, metals (further only non-biodegradable) and subjected to actions. It has been observed by the inventors that the biological activity of the sludge mainly at the bottom of the column for fat and solids separation produces tiny bubbles of gases that triggers buoyancy of immiscible materials in the wastewater and this method of fats and solids removal is considerably activated by gentle agitation of the sludge at the bottom of the column using a mechanical stirrer or through pumping of the clarified wastewater or liquid which is being generated in the process and can be drawn from the column without disturbing the buoyant fats and solids layer at the top. It was also observed that the gentle mixing of the sludge at the bottom of the column enables incessant activity of the microbial community and thereby separation of solids particles was more effective from the wastewater. The generally found immiscible wastewater contaminants such as fats at varying concentrations from 0.05 - 3.0 g/1 and bio-solids of different particle sizes from few microns to 0.8 mm depending on the kind and nature of industries, are clearly separated from the liquid and accumulated above the liquid level by this process. In this invention the transfer of separated and accumulated impurities from top of the

liquid in the column and its collection are effectively done by a device of attachment consisting of a narrow side armed tube or its multiples on the top of the separation column, which also facilitates collection of the gas produced from the column along while discharging and collecting the separated fats and solids through the side arm tube automatically. The extreme pH like less than 3.0 or above 8.0 and the temperature less than 5 °C and above 55 °C of the regime in the process lead to inactivation of the microorganisms involved in the degradation and methanogenic reactions. The exposure to oxygen or air containing oxygen in this process of fats and solids removal causes oxygenation of the clarified liquid, which is undesirable when the subsequent treatment method is anaerobic and leading to methane production or sulphidogensis.
In the present invention it has been observed that by this method separation and removal of particles ranging from few microns to larger 0.8 mm sizes that are otherwise difficult to be removed from the liquid by other known techniques like settling and floatation was easily done continuously. It was also noted that solids at different levels ranging from few milligrams to many grams per liter, usually discharged in the complex wastewaters and are slowly biodegraded by the usual methods gets separated and removed by this method fairly rapid in the presence and absence of fats. The major advantages observed in this method for wastewater treatment are time and cost savings, efficacy in further treatment processes. Value recovery during wastewater treatments from both dissolved impurities, and immiscible fats and solids collected which is otherwise degraded through expensive and elaborate methods, is an added advantage of this invention.
In the present invention it was also observed that otherwise unsettleable bigger organic particles above the said sizes were also found buoyant and enables easy removal from wastewater. The presence of fats while separating along with solids was changed to sticky sludge that affected the easy and smooth removal from the top of the liquid as experienced in the treatment of wastewater from fish processing industry units. Breaking of the clumps through conventional agitation techniques eliminates the clogging resulting from the aggregation of sludge in the process.
This invention enables easier treatment of wastewater from fish processing, slaughterhouse, diary, etc. by the removal of fat, which is not only resistant to biodegradation but seriously,

interferes also with microbial cells. Effective treatment of wastewater in anaerobic system is affected by the fat constituents more than 100 mg /litre which would be present invariably in most of the industrial wastewaters because of the aforesaid reasons. It was noticed that after the removal of solids and fats by this method and device biological treatment of wastewater becomes effective and less cumbersome as there is no need to provide long retention time for waiting to biodegrade both fat and solids compared to dissolved biodegradable contaminants.
FIGURE 1 wherein the various steps of the present invention are carried out, the wastewater containing fats and solids is prepared in a plastic tank 501, wastewater from the plastic tank is pumped to a glass fats, solids and gas separator 502, the fats and solids separated in the glass device is removed by a device and collected to a glass or plastic container 503, the wastewater after separation of fats and solids in the glass separator is passed to an upflow anaerobic sludge bed anaerobic reactor 504, the anaerobically treated effluent from upflow anaerobic sludge bed anaerobic reactor is collected in a plastic tank 505 and the biogas produced during the treatments is measured in a meter 506.
FIGURE 2, the fats and solids separator is made up of glass with 3 nozzles, one for pumping in the fats & solids containing wastewater 507 another in the bottom 508 for pumping in waste water or draining of sludge 511 and liquid, another for letting out the clear liquid free of fats& solids 509. On top of the fats & solids separator a device to collect fats, solids and gas fabricated in glass 512 is fixed using a rubber cork in the real experimental set up unlike shown in the figure 2 as a single unit. The fabricated set up of the fats, solids and gas separation and collection device is further shown in the FIGURE 4. The device to remove fats, solids and gas has two nozzles, one 513 for removing fats & solids which is collected in a plastic or glass container 514 and the second 510 for collecting gas.
FIGURE 3, there is shown a diagram wherein illustration of anaerobic treatment of clarified wastewater in an upflow anaerobic sludge bed anaerobic (UASB) reactor. This reactor vessel has three major components, a conical bottom fabricated in stainless steel, which has a nozzle 515 through which the clarified wastewater from the fats and solids separation device Figure 2 is pumped to the UASB. Above this conical portion a tall glass column 518 containing anaerobic liquid 517, and has stainless steel collar 519 on its top. The stainless steel collar is

provided with 2 nozzles, 522 for circulating liquid inside and 528 for removing liquid 521 after anaerobic treatment by overflow 524 collecting chamber 527. A lid 520 is fixed on the collar with a gas collector 529 and nozzle on the top 525 for releasing gas from the gas collector. Anaerobic sludge bed 516 in the reactor converts dissolved impurities in the wastewater to biogas, a mixture of carbon dioxide and methane which is the dominant gas. The biogas produced in the UASB is collected on the top 526 of the gas collector.
FIGURE 4, a photographic realization of the complete system wherein the process of the present invention is carried out, having fats, solids and gas separation and collection parts and followed by an anaerobic treatment system for the treatment of clarified wastewater from the device described in figure 2.
FIGURE 5 is a photographic representation of one embodiment of a fats, solids and gas separation, and collection system in accordance with the present invention illustrated in figure
2.
According to the preferred embodiment of the invention, fat concentration in the range of 0.1 to 3.0 g/liter in wastewater from the sources such as fish processing, dairy, slaughterhouse, etc. is treated with a liquor containing anaerobic sludge in a liquid column under anoxic condition which enables separation and buoyancy of fat alone or associated with solids above the liquid in the column by operating at biological conditions of temperature 5°C to 55°C and pH between 3.0 to 8.0, thereby generates a fat free effluent. The resulting fat removed wastewater containing mainly the dissolved impurities such as volatile fatty acids, amino acids, proteins and other soluble organic compounds is further sent to a biological treatment system where aerobic or anaerobic processing or both are applied to remove the contaminants from the water.
In yet another preferred embodiment of the invention, concentration of suspended solids in the range of 0.05 gm to 3.0 g/liter having the particles of size ranging from 0.01 to 0.5 mm or is brought to the particles size ranging from 0.01 to 0.8 mm for resulting easy and faster separation of solids from the sources of wastewater such as fish processing, food processing, pulping, slaughterhouse, etc. followed by treating with a liquor containing anaerobic sludge in a liquid column under anoxic condition which enables separation and buoyancy of particles

above the liquid in the column by operating at biological conditions of temperature 5°C to 55°C and pH between 3.0 to 8.0, thereby generates a clear effluent free of suspended particles. The resulting clear effluent containing dissolved impurities such as volatile fatty acids, amino acids, proteins and soluble organic compounds is further sent to a biological treatment system where aerobic or anaerobic processing or both are used to remove the contaminants from the water.
According to a feature of the present invention the fats and suspended solids in wastewaters separated by the biological reactions above the liquid are collected, resulting a concentrated liquid or slurry with fats and solids up to 10-25% for further processing to recover fat and/or generate methane energy in an anaerobic digestion process.
According to a feature of the present invention the treatment of resulting volatile fatty acid and dissolved impurities is further converted to biogas and removed from liquor as biogas by the process of methanogenesis, enabling faster and effective purification of wastewater from industries such as fish processing, slaughter house, food processing, diary, pulping, etc. This invention also features treatment of said clear effluent further to fats and solids removal under aerobic treatment by providing oxygen or air containing oxygen or oxygen bearing chemical compounds like hydrogen peroxide whereby the impurities are oxidized and removed by a population of aerobic sludge to meet discharge standards of wastewater.
The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention.
Example 1
Fish processing effluent was prepared in the laboratory bearing Chemical Oxygen Demand (COD) in the range of 1039 to 1854 mg/1. The wastewater had pH of 6.2 to 7.4, total suspended solids concentration in the range of 422-759 mg/1 and in which the size of particles were between 20 to 600 um, and concentration of fats was ranged between 521-895 mg/1. This wastewater was fed to the fats and solids separation system (process flow diagram) made up of glass column and working volume 61itres, at the rate of 28.61itres/day with a total COD

loading of 5 to 8.8 kg/m3/day. The fats and solids separation system operated was a cylindrical glass column having the size, 70 cm length X 11.25 cm i.d. fitted with a side armed (side arm of 20 cm length X 10 mm i.d. fitted at 10 cm above 70 cm level) glass tube of total length 29 cm andlO mm i.d.) on the top, two side ports, one at the level of 20 cm and the second at 40 cm height, and a bottom port, of 3.82 cm diameter each. The wastewater kept under mixing in a reservoir was pumped through one of the side inlets of the said fats and solids separation system and the outlet for the clear liquid was drained from the second side port. Mixing of liquid in the fats & solids separation system was affected by pumping back liquid free of solids and fats to the bottom of the separation system. The new process separated fats & solids of the said wastewater on introduction to the separation system, accumulated above the clear liquid level. The new method also enabled collection of fats & solids free liquid through the side arm of the system while the top end of the tube facilitated release of gas. The clarified liquid of pH between 6.3 to 7.6 was allowed to pass through the side port other than the wastewater feed port of the fats and solids separation column using the connected rubber tubes of 10 mm i.d., that was partly cycled through the bottom port of the fats and solids separation column and the remaining liquid was treated by pumping through a hybrid anaerobic glass reactor of 9.0 litre working volume, having anaerobic expanded sludge of 1.5 litre at the bottom, floating pall rings on top with retained biomass. Anaerobic biomass of microorganisms capable of degrading waste fish materials and converting to biogas (> 60% methane) was seeded to the fats & solids separation column and anaerobic reactor from a wastewater dumping pond of a fish processing unit and allowed to grow by operating for more than 6 months. The anaerobic reactor liquor pH was in between 5.8 to 7.8 and mostly in the near neutral range of 6.6 to 7.5. The entire experimentation was conducted at the temperature between 18° and 35° Celsius. Biogas from the anaerobic reactor and fats & solids separation systems were metered in a gas flow meter connected to the systems through a rubber tube of 10 mm i.d. Biogas produced was in the range of 2.8 - 3.2 liters/day. Analytical data of the wastewater from the fats & solids separation system and anaerobic treatment is presented in Table 1.
Table 1 .Characteristics of fish processing wastewater upon fats and solids separation and anaerobic treatment at hydraulic loading rate of 28.61itres/day (13.6 cubic metre/m3day"1) in

the fats and solids separation.

(Table Removed)
Example 2
Effluent was prepared in the laboratory resembling fish processing wastewater bearing Chemical Oxygen Demand (COD) in the range of 990- 3882 mg/1. The simulated fish processing wastewater had pH of 6.2 to 7.4, total suspended solids concentration in the range of 300-3450 mg/1 and in which the particles sized between 20 to 600 urn, and fats concentration ranged between 248- 2438 mg/1. This wastewater was fed to the fats and solids separation system and working volume 6 liters at the rate of 19.8 liters/day with a total COD loading of 3.5 to 12.8kg/m3/day. The fats and solids separation system operated was a cylindrical glass column having the size, 70.5 cm length xl 1.45 cm diameter fitted with a side armed (20 cm length xlO mm i.d.) glass tube (29 cm length xlO mm i.d.) on the top , two side ports and a bottom port of 3.82 cm diameter each. The wastewater inlet to the said separation system was provided from a side port and outlet from another side port. The new process separated fats and solids of the said wastewater on introduction to the separation system, accumulated above the water level and collected through the side arm while the top end of the tube facilitated release of gas. The clarified liquid of pH between 6.3 to 7.6 was allowed to pass through the side port other than the wastewater feed port of the fats and solids separation column using the connected rubber tubes of 10 mm i.d., that was partly cycled through the
bottom port of the fats and solids separation column and the remaining liquid was treated by pumping through a hybrid anaerobic glass reactor of 9.0 liter working volume, having anaerobic expanded sludge of 1.5 liters at the bottom, floating pall rings on top with retained biomass. Anaerobic biomass of microorganisms capable of degrading waste fish materials and converting to biogas (> 60% methane) was seeded to the fats & solids separation column and anaerobic reactor from a wastewater dumping pond of a fish processing unit and allowed to grow by operating for more than 6 months. The anaerobic reactor liquor pH was in between 5.8 to 7.8 and mostly in the near neutral range of 6.6 to 7.5. The entire experimentation was conducted at the temperature between 18° and 35° Celsius. Biogas from the anaerobic reactor and fats & solids separation systems were metered in a gas flow meter connected to the systems. Biogas produced was in the range of 2.5 - 3.5 liters/day. Analytical data of the wastewater from the fats & solids separation system and anaerobic treatment is presented in Table 2.
Table 2. Characteristics of fish processing wastewater upon fats and solids separation and anaerobic treatment at hydraulic loading rate of 19.8 litres/day (6.5 cubic metre/m3day"1) in the fats and solids separation.

(Table Removed)
THE MAIN ADVANTAGES OF THE PRESENT INVENTION:
1. Avoids addition of chemicals or gases unlike in the prior arts of floatation techniques
and hence the innovation reduces the extra treatment costs required to maintain,
chemicals or gas storage and handling equipment
2. Substantial reduction in the size of wastewater treatment plants for the removal of fats
and solids containing wastewaters also reduces the costs of wastewater treatment
further down.
3. Recovery of the fats from wastewaters becomes simple and efficient
4. The present invention is more efficient and less time consuming for the treatment of
wastewater containing fats and other solids
5. Can be retrofitted in the existing industrial wastewater treatment plants of various
sizes and capacities .
6. Entire process and operation are environmental friendly.
7. Eliminates interferences in the treatment of wastewaters containing dissolved BOD.

We claim:
1. A device for treating wastewater containing fats and solids comprising:
a fats and solids separator which consist of first nozzle (507) for pumping in the wastewater containing fats and solids, a second nozzle (508) in the bottom for pumping in liquid containing wastewater and anaerobic sludge, a third nozzle (509) for letting out clear liquid free of fats and solids, a fourth nozzle (513) for removing fats and solids and a fifth nozzle (510) for collecting gas;
in combination with an upflow anaerobic sludge bed reactor having at least one liquid column (518) containing anaerobic sludge bed(516) ,a minimum of one inlet (522) arranged to feed wastewater to the liquid column, two outlets for removing clear wastewater, solids and fats and a nozzle (515) is located at the bottom. * 2. The device as claimed in claiml, wherein a nozzle (515) is located at the bottom of anaerobic sludge bed reactor through which the clarified wastewater from the fats and solids separation device is pumped in.
3. The device as claimed in claiml, wherein a lid (520) is fixed on the collar (519) with a
gas collector (529) on the top of the anaerobic sludge bed reactor.
4. The device as claimed in claiml, wherein the said device automatically releases the
gas through the outlet (525) of the column while removing the buoyant fats and solids.
5. A method for treating wastewater containing fats and solids by floatation comprising
the steps of:
a) introducing the wastewater containing fats and solids to a liquid column containing
anaerobic sludge;
b) mixing the content of step (a), wherein biological activity of the anaerobic sludge
produces tiny bubbles of gases allowing the immiscible fats and solids in the
wastewater to float;
c) removing the floating material as obtained from step (b) from the liquid to obtain
wastewater free of suspended solids and fats ;

d) further processing the wastewater free of suspended solids and fats as obtained from step (c) in a biological treatment system wherein anaerobic processing is carried out to remove contaminants from the wastewater.
6. The method as claimed in claim 5, wherein the said wastewater contain miscible
and/or immiscible fats and solids in colloidal suspension which are not settleable.
7. The method as claimed in claim 5, wherein the wastewater is introduced to the liquid
column at a temperature in the range of 5 °C to 55°C and pH in the range of 3.0 to 8.0.
8. The method as claimed in claim 5, wherein the wastewater introduced to liquid
column containing anaerobic sludge results in biochemical changes in the liquid
column.
9. The method as claimed in claim 7, wherein the resulting biochemical reactions
generates short chain fatty acids that include acetic acid, and releases carbon dioxide,
methane or hydrogen sulphide or a mixture thereof in the said liquid column.
10. The method as claimed in claim 5, wherein the liquid column containing wastewater is
having facility to mix the content using mechanical stirrer or by circulation of liquid
within.
11. A device and a method for treating wastewater containing fats and solids substantially
as herein described with reference to the example and drawings accompanying this
specification.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=tNzh6Vh0uE5hCIhuYbbOaw==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

279467

Indian Patent Application Number

665/DEL/2009

PG Journal Number

04/2017

Publication Date

27-Jan-2017

Grant Date

23-Jan-2017

Date of Filing

31-Mar-2009

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI - 110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	VATTACKATT BALAKRISHNAN MANILAL	REGIONAL RESEARCH LABORATORY, CSIR, THIRUVANANTHAPURAM 695019, INDIA.
2	AJIT HARIDAS	REGIONAL RESEARCH LABORATORY, CSIR, THIRUVANANTHA PURAM 695019, INDIA.

PCT International Classification Number

C02F 3/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA