CS270926B1 - Method of pre-treatment or treatment of waste waters that are soiled by substances of organic origin - Google Patents

Abstract

Within the first phase, the contaminated water gets coagulated, within the second phase, it is treated, so to achieve a pH 5 to pH 7 and retreated, e.g. by calcium hydroxide Ca(OH)2, in the third phase, the obtained precipitate gets flocculated by a flocculating agent on a polyacrylamide bases. The resulting flakes are separated.<IMAGE>

Description

The invention relates to a process for the pre-treatment and purification of waste waters contaminated with organic substances, in particular waste water from technological processes in which

Processes raw material of animal or vegetable origin, eg from meat processing plants, poultry:

incineration plants, rendering plants, tanneries, vegetable processing plants, etc. <

Effluent waters heavily contaminated with substances of organic origin (raw water):

are mostly cleaned aerobically or anaerobically. The efficiency of cleaning depends on the nature;

and contamination content, to fluctuations in contamination at the inlet, at the temperature of the inlet water. On:

large changes (jumps) in these parameters of the biological treatment plant react very slowly and, in most cases, biological treatment processes are interrupted, so that wastewater treatment is not carried out.1 /

This lack of biological wastewater treatment removes the pretreatment method;

whose essence consists in coagulation of waste water free of coarse impurities with a suitable coagulant (precipitant), then it is purified and adjusted to pH, flocculated:

a polyacrylamide-based catalyst (PAA). After flocculation, the sludge is separated from the slurry, which is suspended in the sludge cloud in the slurry. A suitable separation device here is a flotation or electroflotation bath.

Before the purification of raw water in front of the biological treatment plant we achieve a constant and mainly:

lower pollution of waste water flowing to the biological treatment plant. Pre-cleaning efficiency ·?

it varies between 5o and 9o% for various parameters. This pre-purification removes od-j?

especially water, fats, proteins, undissolved and some dissolved substances. Ze suro-;

First, coarse contaminants such as sand, horn, bones, bristles, roots, etc., are removed according to the type of water in the sedimentation tank or on the screened screens or by means of filters. Depending on the amount of contamination (turbidity, coloring), we use a coagulant, which consists mostly of salts Pe ^ ⁺ , Pe ²⁺ , Al ^ ⁺ . Coagulation will dissolve dissolved impurities <

in the form of colloidal particles, proteins, fats, starches, etc., and ee to solidify in the form of fine flakes dispersed in water. Coagulation reactions need to be ..

time is from 60 seconds to 60 minutes. This delay will ensure a coagulation reactor, for the better.

the course of the reactions may be equipped with a high-speed stirrer. After coagulation, the pH of the water is reduced.

Acid is added to adjust the pH and calcium hydroxide is usually added to finish the suspension and coagulation flakes. For easier separation of fine flakes from water:

dosing according to the amount of flocculants based on PAA. This substance aggregates small flakes into larger flakes and forms a snowflake cloud. A time lag of 30 seconds to 30 minutes is required for flake formation. When creating a flocculent cloud, it is necessary to maintain laminar flow in the case of continuous water flow. Flakes from the flake cloud are separated either by sedimentation, '<

filtering, flotation, or electroflotation. This theology is applied in both continuous and discontinuous lines. With this method of purification or pre-purification, the following efficiencies are achieved in the following parameters: suspended solids - 7 to 95 fats - efficiencies of 85 to 100%. For further biological treatment, the raw water pre-treatment method allows to ensure constant parameters when fluctuations * occur at the inlet of the plant. ?

The drawing shows a diagram of the waste water pretreatment technology. Raw water

And enters mechanical pre-cleaning 1.

Raw water is pumped from the accumulation well 2 into the coagulation reactor 3. The coagulant 2 is metered in front of the # reactor in the pipeline by means of a plunger dosing pump 10. The batch size depends on contamination. Coagulation reactor 2 cylindrical vessel o?

volume corresponding to a delay of 2o minutes. The reactor is stirred with a high-speed stirrer. The slurry flows from coagulation reactor 3 by gravity to flocculation reactor 4. In the line between coagulation 3 and flocculation reactor D, a slurry of Ca (OH) g is metered for clarification and the pH is adjusted with acid 7. A flocculent cloud is formed in flocculation reactor 4. The flocculation reactor 4 is a cylindrical vertical vessel having a volume corresponding to a residence time of 20 minutes, with a lower tangential inlet to ensure slow stirring. From the flocculation reactor ?:

water overflow β through a flocculated cloud into the electroflocator (electroseparator) 5, where the flakes are separated in the form of sludge В and water C. PAA / is dosed in front of the flocculation reactor.

CS 270926 Bl from storage tank 6 · Purified water C flows through the overflow, sludge at surface В is sucked out or rake to the tank or for further use ·

The process according to the invention can be used for pre-treatment of waste water in meat-processing plants, poultry farms, tanneries, vegetable processing and processing plants, processing plants and wherever impurities can be economically coagulated and floated.

Claims (2)

1. A process for pretreatment or treatment of wastewater contaminated organic substance, characterized in that the polluted water is coagulated in a first phase a coagulant salt based ferric ions Fe @ ⁺ Pe of Fe ²⁺ or aluminum ions Al ⁺ ^, in the second stage is adjusted to a pH of 5 to 7 and clarification is carried out, for example with a calcium hydroxide Ca (OH) 2 suspension or sodium hydroxide solution NaOH or potassium hydroxide solution KOH, in the third phase the resulting precipitate in the purified water suspension is flocculated with a polycoagulant or flocculant based on polyacrylamide, in the fourth phase the flakes are separated in the form of sludge which is sucked off, 2. The method of pre-treatment or sewage treatment according to claim 1, characterized in that coarse solid impurities with a diameter greater than 0.5 mm are separated before the first stage,