RU2184085C1 - Method for purifying meat house sewage water and obtaining fat concentrate - Google Patents

Abstract

FIELD: meat house sewage processing industry. SUBSTANCE: method involves separating fat mass by pressure flotation without using reactants; providing thermal treatment of obtained fat mass in two stages under vacuum while mixing it: at first stage, thermal treatment is conducted at temperature of 70-90 C and residual pressure of 30-40 kPa to complete dehydration of product, and at second stage, dehydrated fat mass is heated at temperature of 130-150 C and residual pressure of 15-20 kPa for 0.5-1.0 hour; cooling and pouring ready product, i.e., fat concentrate; providing additional purifying of remaining sewage water by known method. Pressure flotation is performed at excessive pressure of 0.3-0.4 MPa at air content of 1.0-4.0 wt. % in air-water emulsion. Basic fatty component is removed after reactant-free flotation, with fat content in sewage water at inlet end being within the range of 1,500-2,000 mg/l and at outlet end up to 110-150 mg/l. EFFECT: increased efficiency in purifying sewage water and provision for obtaining fat concentrate free of contaminants and having fat-and-acid content corresponding to that of inedible fat. 5 cl, 1 ex

Description

 The invention relates to the field of purification of technological waste water from meat plants from emulsified fat.

 A known method of wastewater treatment (Patent RU 2107039, class C02F 1/58, BIPM 8, 1998, p. 382) by introducing spent electrolyte solutions into wastewater, followed by separation of the aqueous and organic phases. In this case, the spent electrolyte is introduced in an amount that provides a certain mass ratio of organic substances to the metal content in the electrolyte.

 The disadvantages of the method is the use of environmentally hazardous electrolytes; the need to work with acidic effluents, which makes special demands on equipment and pipelines; extraction of heavy metals into the oil phase, where they additionally react with the free fatty acids that make up the oil phase. The presence of such impurities makes it difficult to convert the allocated oil phase into a marketable product.

 A known method of wastewater treatment (Patent RU 2102979, class C 02 F 1/52, 1/40, BIPM 11, 1998, p. 213) by treating them with a reagent solution, which is activated by a magnetic field before treatment. Water after reagent treatment is maintained until relaxation processes are completed in them.

 The disadvantage of this method is the complexity of the technology, including magnetic processing of the reagent and the exposure of water to the end of the relaxation processes, as well as the transition of the reagent to the precipitate formed, which makes it difficult to obtain a marketable product on its basis.

 Closest to the claimed technical solution is a method of wastewater treatment of a meat factory by treating with a coagulant consisting of iron chloride, iron sulfate, iron hydroxide formed as a result of galvanocoagulation and with the additional introduction of sodium bicarbonate. Wastewater after mechanical treatment enters the heat treatment, as a result of which part of the proteins and fat precipitate. Then, partially purified effluents are sent for further processing (Patent RU 2141455, class C 02 F 1/52, 11/20/99).

 The disadvantage of this method is the need for heat treatment of the entire volume of wastewater; obtaining two types of sediment: after heat treatment and, after the main, after purification with a coagulant, which contains the coagulant passing into it and iron salts formed during the reaction with free fatty acids that make up the resulting fat mass. Cleaning from impurities of the resulting fat mass is complicated and complicates its processing into a commercial product.

 The aim of the invention is the treatment of wastewater from meat processing plants with the release of grease from industrial effluents and turning it into a commercial product (fat concentrate) by further heat treatment.

The technical result is achieved in that the separation of the grease mass is carried out by pressure flotation without the use of reagents, and the heat treatment of the resulting fat mass is carried out in two stages under vacuum, and in the first stage, the heat treatment is carried out at a temperature of 70-90 ^o C and a residual pressure of 30-40 kPa until complete dehydration product in the second stage, the dehydrated fat mass is heated at a temperature of 130-150 ^o C and a residual pressure of 15-20 kPa for 0.5-1.0 hours, followed by cooling and draining of the finished product - fat concentrate - and purification of the remaining wastewater in a known manner, taken as a prototype, or by any known method that provides the required parameters for wastewater treatment to standard values.

 Pressure flotation is carried out at an excess pressure of 0.3-0.4 MPa with an air content in the air-water emulsion of 1.0-4.0% by volume.

 The main fat component is removed after a reagent-free pressure flotation with a fat content of 1500-2000 mg / L at the inlet to 110-150 mg / L at the outlet.

 The resulting fat concentrate does not contain impurities due to the use of coagulants, flocculants and spent galvanic electrolytes, and has a fatty acid composition corresponding to the fatty acid composition of technical fat.

 The analysis of the prior art cited by the applicant, including a search by patent and scientific sources of information and identification of sources containing information about analogues of the claimed invention, made it possible to establish that the applicant did not find an analogue characterized by features identical to all existing features of the claimed invention, and the definition of the above prototype analogues , as the closest in the set of features of analogues, allowed to identify the set of essential distinguishing features in the declared volume kTe set forth in the claims.

 We give an example implementation of the proposed method.

 Example.

 Wastewater containing 1800 mg / l of fat at the inlet is subjected to pressure flotation at an overpressure of 0.35 MPa and an air content in the air-water emulsion of 3.0% by volume without the use of reagents.

The separated fat mass is fed into a thermoreactor with a paddle mixer, in which, at the first stage, the fat mass is heat treated at a temperature of 80 ^° C and a residual pressure of 35 kPa until the product is completely dehydrated.

Then, in the second stage, the dehydrated fat mass is heated to 140 ^{° C.} and held for 0.8 hours at this temperature and a residual pressure of 18 kPa. The resulting fat concentrate is cooled to a temperature of 80 ^o C and drained from the reactor. The results of the analysis of wastewater purified from fat show a fat content of 130 mg / l.

 A partially purified wastewater solution is sent for treatment with a complex coagulant consisting of iron chloride, iron hydroxide, iron sulfate, formed as a result of galvanic coagulation at pH greater than 7.5 and with the additional introduction of bicarbonate, which ensures the required wastewater treatment parameters to standard values.

Here are the indicators of the composition and quality of the fat concentrate obtained by the proposed method:
Consistency, at 20 ^o C: from solid to oily;
Color: dark brown;
Mass fraction of moisture,%, no more: 2;
Acid number, mg KOH / g: 140-170;
Mass fraction of unsaponifiable substances,%: 1.5-3.0;
Mass fraction of substances insoluble in ether,%: 8-18;
The titer, ^o C: 35-40.

The fatty acid composition of the fat concentrate, wt.%:
C ₁₆ ⁰ (palmitic acid) - 20-35
C ₁₈ ⁰ (stearic acid) - 10-20
C ₁₈ ^{1 =} (oleic acid) - 40-50
C ₁₈ ^{2 =} (linoleic acid) - 5.5-7.0
C ₁₈ ^{3 =} (linolenic acid) - 1.0-3.0
Others (C ₁₄ ⁰ , C ₁₆ ^{1 =} , C ₂₀ ⁰ - myristinonic acid, palmitoleic acid, arachinic acid) - 0.5-1.2
The proposed method for wastewater treatment in meat processing plants and obtaining fat concentrate allows, in comparison with the prototype:
- reduce energy consumption due to heat treatment under vacuum of a relatively small, compared with the volume of wastewater, volume of the allocated fat mass;
- combine the heat treatment process with deodorization of the obtained concentrate;
- reduce the consumption of complex coagulant by removing the main amount of fat from wastewater by the method of non-reactive pressure flotation;
- get a fat concentrate that does not contain harmful impurities due to the use of coagulants, flocculants and spent galvanic electrolytes, and has a fatty acid composition corresponding to the fatty acid composition of technical fat.

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:
- a tool comprising the claimed invention is intended for use in wastewater treatment of meat plants;
- for the claimed invention confirmed the possibility of its implementation using the methods described in the application;
- the tool that makes up the subject of the invention, is able to achieve the technical result.

Claims (4)

1. The method of wastewater treatment in meat processing plants and obtaining a fat concentrate, including the separation of grease from the industrial wastes of a meat factory, separation of mechanical impurities and heat treatment, characterized in that the separation of the fat is carried out by pressure flotation without the use of reagents, and the heat treatment of the resulting fat is carried out in two stages under vacuum at a paddle stirring, wherein in the first step heat treatment is carried out at a temperature of 70-90 ^o C and a residual pressure of 30-40 kPa until completely dehydrated Niya product; in the second stage, the dehydrated fat mass is heated at a temperature of 130-150 ^o C and a residual pressure of 15-20 kPa for 0.5-1.0 hours, followed by cooling and draining of the finished product - fat concentrate.  2. The method according to p. 1, characterized in that pressure flotation is carried out at an excess pressure of 0.3-0.4 MPa with an air content in the air-water emulsion of 1.0-4.0% by volume.  3. The method according to p. 2, characterized in that the main fat component is removed after reagent-free flotation when the fat content in the wastewater at the inlet is 1500-2000 mg / l and up to 110-150 mg / l at the exit.  4. The method according to p. 3, characterized in that the resulting fat concentrate does not contain harmful impurities due to the use of coagulants, flocculants and spent galvanic electrolytes, and has a fatty acid composition corresponding to the fatty acid composition of technical fat.