CS223376B1 - Method of separation of the fat from mechanically precleaned refuse waters - Google Patents

Description

The invention relates to the physicochemical separation of fatty substances from mechanically pre-treated waste waters, in particular from meat-processing plants, food processing plants and other plants producing waste waters loaded with residual contents of free and emulsified fats. and

It is an object of the invention to significantly reduce the content of fatty substances in the waters fed to the biological treatment section or discharged into surface raft.

Waste water supplied for biological treatment often does not meet the requirement of permissible fat content. In food processing plants, even after the introduction of water pre-purification, a reduction in fat content below 100 mg is not achieved. dm ' ³ .

The grease traps used hitherto are characterized by low efficiency, which is due to the principle boundary of the gravitational separation of greases and influenced, inter alia, by inappropriate aeration.

Due to insufficient results in the reduction of fat content in the traps, the introduction of circular sedimentation tanks of the Dorr type and pressure flotation for the treatment of wastewater from the greasy industry was started. However, the fat removal efficiency of said apparatus is still not satisfactory.

In the case of sedimentation tanks (circular settlers), the sharpness of the gravitational separation is also low due to the fact that some of the fats are carried to the surface in the form of a foam, especially when mixing with compressed air takes place.

The reason for the lower efficiency of the pressure flotation can be seen mainly in the imperfect or unsuitable reagent regime.

The above-mentioned disadvantages of the prior art methods of fat separation are eliminated by the process according to the invention, which is based on the separation of fats from mechanically pre-treated waste water of meat processing plants, poultry plants and other food plants by flotoflocation in suitable flotation equipment. , of aluminum in the amount of 100 to 750 mg per dm ^{3 of} purified water and of alkaline, alkaline earth metal hydroxides up to pH 9 to 10 together with a cationic flocculating agent of the condensation product type epichlorohydrin and polyamide amine dicarboxylic acid 30 to 100 mg per 1 dm ^{3 of} purified water and an anon ^with a higher hydroxylic acid of the higher fatty acid type ^with C 16 -C 16 carbon atoms and their soaps in an amount of 50 to 100 mg per 1 dm ^{3 of} purified water.

This procedure removes free and de-emulsified fatty substances from the purified water, which are absorbed at multiple phase interfaces and concentrated in the flotation foam. The invention is further described in the following examples.

Example 1

Waste water from the meat processing plant contained 1457 mg. dm ^-3 fatty substances, 5520 mg. . dm ^-3 BOD5 and 3686 mg. dm ^-3 insoluble matter. The separation process was carried out continuously in the operational flotation plant of domestic production for several days. The reaction electrolytes used were ferric chloride (FeCl3.6H2O) in an amount of 100-500 mg. dm ³ and sodium hydroxide (NaOH) to pH = 9-10. To flocculate the resulting flocculent cloud formed by ferric hydroxide [FefOH], a domestic reagent based on the condensation product of epichlorohydrin and polyamidamine dicarboxylic acid was dosed in an amount of 30 to 100 mg. dm ^-3 and to the flake cloud hydrophobic agent oleic acid (C17H33COOH) in an amount of 50 to 100 mg. dm ^-3 . Both flocculating and hydrophobicizing agents were dosed with reaction (agitation time up to 1 minute). Flotation time representing wastewater treatment time ranged from 20 to 30 minutes, amount of purified water was 7 to 9.5 m ³ .h ^-1 . contained 29 mg. dm ^{-3 of} fatty substances, 633 mg. dm ^{-3 of 3} BODs and 240 mg. dm ^{-3 of} insoluble substances. The cleaning efficiency related to fat substances was 98%, to BODs 88.5 percent and to insoluble substances 93.5%. Example 2

The waste water from the poultry plant contained 493 mg. dm- ³ fatty substances, 620 milligrams. dm ³ BODs and 1.12 mg. dm ^-3 insoluble matter. The separation process was carried out for several days on an industrial scale in a non-pressurized flotation plant of domestic production. The reaction electrolytes used ferric chloride (FeCls. 6Η2ΟΪ in the amount of 100 mg. Dm ³ and sodium hydroxide (NaOH) up to pH = 10). The domestic reagent based on the condensation product epichlorohydrin and polyamidamine dicarboxylic acid in the amount of 30 to 100 mg. dm ^-3 and to the flake cloud hydrophobizing agent oleic acid (C17H33COOH) in an amount of 150 mg. dm ^-3 .

Flotation time ranged from 20 to 30 minutes, cleaning performance from 7 to 9.6 m ³ . h “ ¹ . Purified water contained 36 mg. dm ³ fat substances, 412 mg. dm ³ BODs and 0.2 mg. . dm ^-3 suspended solids. The cleaning efficiency relative to the fatty substances was 92.7%, the BODs 33.5% and the insoluble substances 82.1%.

Claims (1)

SUBJECT Process for separating fats from mechanically pre-treated wastewater of meat-processing plants, poultry plants and other food plants by flotation in a suitable flotation plant, characterized in that the treated water is dosed with reaction electrolytes - trivalent iron salts of aluminum in the amount of 100 to 750 mg per dm ³ water and alkaline earth metal hydroxide to pH = 9-10 together with cationic OF THE INVENTION OF THE INVENTION A flocculating agent of the condensation product of epichlorohydrin and polyamidamine dicarboxylic acid having a carbon number of C6-C9 of 30 to 100 mg per dm ^{3 of} purified water and an anionic hydrophobicizing agent of higher meat liquids having a carbon number of C16-C18 and their soaps. 50 to 100 mg per dm ^{3 of} purified water.