DE3018086A1 - Purifying waste waters contg. (in)organic colouring materials - by passing over adsorbent waste prods. and/or by introducing filter ash or flue dust - Google Patents

Abstract

Waste waters contg. up to 20 kg/m3 dissolved and/or colloidally distributed inorganic and/or organic colouring materials are purified by adjusting pH 1-14 to esp. pH 6-8 and (a) passing over adsorbing waste prods., (A), pref. at a surface loading of 10 (3 to 0.6) m3/m2 adsorber surface hr. and/or (b) introducing dry electrostatic filter ash or flue dust in quantities of 10-150 kg/m3 waste water, whereby the colouring materials are flocked and electrochemically bonded. (A) consists of wet ash, xylite, wet ash xylite, partly coked ash xylite and thermally or chemically activated xylite. Pre-purified waste waters can be discoloured economically to form clear water. O2-consumption in main drainage stream is reduced. Discolouration can reach 100%.

Description

Tifel of the invention y. -

Process for decolorizing waste water

Field of application of the invention

The invention relates to a method for decolorizing the in particular in chemical industrial centers and in dear processing industry colored waste water produced by the coal and energy industry · The process is particularly suitable for decolorization of physico-chemical or biological pre-treated wastewater as well as for the removal of organic and inorganic dyes from water

Characteristics of the known technical solutions

The processes known in the art for decolorizing industrial wastewater are for the most part based on adsorption and elimination reactions with Α-carbon and chemicals · So is in the DE-GS 2055 ö5O a method for cleaning organically contaminated Watering described by the catalytic degradation of organic substances · The implementation and reaction of the to be degraded Air required for substances is introduced into the water by means of a surface aerator or plotting stirrer and distributed

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The catalyst used is predominantly pretreated Α-carbon in granular Form used. In addition to the use of the expensive catalyst is disadvantageous in this process that the residence time in Reaction basin increases with increasing amount of water and the cleaning effect decreases

In a similar process, Α carbon is used as a catalyst for the treatment of waste water from the paper _y leather, textile and cleaning industries (DE-OS 2050 874 and BE-OS 2437 745). The wastewater is introduced into a reaction chamber filled with a porous catalyst mass based on carbon or ion exchanger, and this catalyst-water mixture is floated with air. During catalytic oxidation, organic substances are preferably absorbed. Despite the high expenditure on equipment, only partial discoloration is achieved.

In DE-OS 2509 432 a method for removal is also used of organic substances with the help of Α-carbon or the use of inorganic adsorbents (kieselguhr, SIlicagel or AIgO ^) described. The adsorbents must preferably in granulated form

In another known method, a physico-chemical-biological-bacteriological process is used to decolorize the wastewater Cleaning described (DE-OS 2150 480). In addition to the use of expensive adsorbents and chemicals must be a pH correction and the removal of the Contaminants are made

When using sound energy and ozone (DE-OS 2219 651) A color quality improvement from cloudy-dark brown to translucent amber-colored achieved · In the process described the capacity of the sonication chamber is limited to 26.5, and a high level of technical equipment is required.

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To decolorize acidic dissolved dyes is still available a method known (DE-OS 2515 175), in which the dye is precipitated in the presence of a certain amount of aluminum sulfate with dicyandiamide-formaldehyde resin. With this procedure however, only acidic dye with a known concentration can be optimally precipitated.

The use of finely divided ozone for the clarification of colored and / or cloudy wastewater, if necessary with addition of chlorine is described in DE-OS 2,434,061. This procedure only shows a good effect at low concentration, therefore it is usually necessary to dilute this wastewater, otherwise heavy encrustations will occur.

Another known method (DE-OS 2711 072) uses ultrafiltration with semipermeable membranes, which consist of a polysulfone film which is coated with polyethyleneimine, to remove color bodies. This method is preferably applicable for wastewater from the paper and pulp industry. A major disadvantage of this method is high cost in addition to the fact that the process in a pH range is carried out by 9 to 14 and at a certain temperature range (37.8 to 81.1 ⁰ G). The solids must be removed from the wastewater as far as possible in order to avoid contamination of the ultrafiltration membrane.

Highly water-soluble anionic and cationic dyes can be obtained by the process described in DE-OS 2,440,379 by means of brown coal and with the addition of coagulants, Flocculants or decolorizing agents (activated charcoal) are removed. Similar processes with the same adsorbent Lignite or raw lignite or lignite dust are in the patents DD-PS 62 785, DD-PS 78 967 and DD-PS 70 529 described. The main disadvantage this above The process consists in using the raw lignite, which is valuable as an energy source, as an adsorbent will.

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Object of the invention

The aim of the invention is to eliminate the deficiencies shown in the known technical solutions and to provide a flood-appropriate solution Purification to achieve visually clean wastewater with low economic costs.

Explain the essence of the invention

The invention has for its object to provide a method which, laßaschexylit the adsorption ability of xylitol, exploits teilverkoktem Aschexylit and thermally or chemically activated ash and xylitol and / or J ¹ Iockungseigenschaften of KLektrofilteraschen, fly ash from combustion plants, ITaßaschen and / or Coupling with wastewater pre-cleaned according to biochemical or physico-chemical processes, which despite multi-stage treatment still contains dyes and thus water pollutants and which, due to their unsightly appearance, cast doubt on the quality of the drainage water. The cleaning is achieved with little economic effort.

According to the invention the object is achieved in that the colored Wastewater using partially coked ashexylite or crude xylite and / or filter ashes from power generation plants that work with solid fuels or waste products containing xylitol, partially coked ashexylite or with xylitol, which is activated by methods known per se, such as, for example, acid treatment is to be cleaned.

The principle of the process is based on the fact that the pre-treated wastewater to be decolorized has a dye concentration up to about 20 kg / m of anionic, cationic or nonionic Dyes through the adsorbing waste products, such as partially coked ashexylite and / or raw xylite or activated raw xylite, is passed, the adsorber with

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A surface load of up to 10 no waste water / m adsorber area and hour, preferably 3 to 0.6 nr / m · h · works.

The pH of the wastewater is between t and 14 and will preferably set to 6 to 8.

The invention is also based on the object Flocculation property of the electric filter ashes and the flue dust to remove organic and inorganic dyes from water. To do this, the sewage placed in a known stirred tank and with dry electrostatic precipitator ash or fly ash in an amount from 10 kg / m to 150 kg / nr wastewater added

In a downstream settling device known per se, For example, a thickener, with a residence time of 1 to 3 hours, preferably 1 hour, the dye-laden Solid phases separated by sedimentation and the decolorized clear water phase in the receiving water derived.

For decolorization of water, the mixtures of organic and inorganic dyes, the waters are depending on the concentration of organic and inorganic dyes passed for adsorption over xylitol-containing waste products and for the subsequent flocculation mixed with electrostatic precipitator ash or fly ash or for flocculation with electrostatic precipitator ash or flue dust and then passed over xylitol-containing waste products for adsorption.

In the process according to the invention, the colored wastewater, which is generally difficult to treat, can be carried along with it cheap and widely available waste of the coal and energy industry, such as laßaschexylit, partially coked ashexylite and electrostatic precipitator ash, more advantageous and process it in a simple way by using the Color components are reduced or eliminated entirely, whereby a cleaning effect suitable for the flood is achieved ».

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As a result, there is a reduction in the consumption in the receiving waters and the costs for the downstream water users decrease

Another advantage of the method according to the invention is its low operating complexity due to a simple one Technology·

On the basis of pure organic water-soluble dyes, it was demonstrated that the waste products of partially coked ashexylite or xylitol and electrostatic precipitator ashes can be used.

Embodiment 1

The following organic dye solutions were used for the laboratory tests used at a concentration of 100 mg / 1:

Methylene Blue, Malachite Green, Eriochrome Blue Black R, Eriochrome Black T, Eriochrome Red, Murexide, Toluidine Blue 0, and Thionine. The light transmittance of the solution is between 0 and 20 %. 100 mg of the o · g · dyes are dissolved in 1 liter of water and passed through an adsorption column with a diameter of 7.3 cm and a xylitol amount of 800 g at optimal flow rates of 50 ml / min given. This corresponds to a flow velocity of 7 m / h

The discoloration effects are between 25% and 100% depending on the flow rate and concentration of the dyes.

The above test solutions were also used for flocculation with electrostatic precipitator ash »

In the respective dye solutions with pH 7.0, 3 »0 and 1.5, 60 g or 100 g, which corresponds to 60 kg / nr or 100 kg / m, were added to electrostatic precipitator ash and stirred for 5 minutes. To Sedimentation or filtration of the suspension through a folded filter there were discoloration effects compared to the starting solution of 90 to 100%.

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Embodiment 2

10 l of biologically treated wastewater with a light permeability of 20 % and a pH value of 8 are passed over a xylitol-filled adsorber, area 41.8 cm, at a flow rate of 0.6 l / h. The decolorization effect is 50%.

Embodiment 3
(see figure 1)

The waste water enters the stirred tank 2 through line 1, In Dry filter ash is introduced into this container with stirring via addition path 12, the dye components being electrochemically are bound to the ash particles. Acid can be metered in through line 11 to adjust the pH. Then it will be the ash-water mixture via lines 5 and 6 to the sedimentation tank 3 or to filter 4. The separated clear water is either fed through the lines 7 or 10 to the receiving water 16 or with acidic or alkaline water through the neutralization tank 15 sent, in which a neutralizing agent is metered through line 17 to a waste water with a Maintain pH from 6 to 8 »..

The dye-laden ashe residue from the sedimentation tank 3 or the filter residue from the filter 4 is given to the landfill via the lines 8 or 9

Embodiment 4

(see figure 2)

The wastewater passes through line 1 into the adsorber 13, which via the addition path 14 with xylitol, uassaschexylit, partially coked xylitol, or thermally or chemically activated ash is filled with xylitol.

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The decolorized wastewater is introduced into the stirred tank 2 through line 18 and the electrostatic precipitator ash through line 12 In this container 2, the dyes are electrochemically bound to the ash particles.

The ash-water mixture passes through line 5 into the sedimentation tank 3, in which the solids are separated by sedimentation are or · through line 6 in the filter 4 »where the separation takes place by filtration. The in each case applied Residues arising from separation processes are fed through lines 8 and 9 to a landfill. The cleaned Waste water (line 7 »9 and 19) is fed to the receiving water

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Claims (4)

Invention claims 1. Process for the purification of waters that contain real dissolved and / or colloidally distributed inorganic and / or organic dyes up to approx Up to 14 accruing water, preferably adjusted to a pH value of 6 to 8, are passed over adsorbing waste products, such as uass ash, xylitol, llaßaschexylit, partially coked ashexylite and thermally or chemically activated xylitol, and / or dry electrostatic precipitator ash or plug dust into the water entered and the dyes are flocculated by the ash particles and bound electrochemically. _: 2. The method according to point 1, characterized in that that the wastewater via raw xylitol, activated raw xylitol or xylitol-containing waste or partially coked Ashexylite with a surface loading of up to 3 2
10 m per m adsorber surface and hour, especially 3 3 2
up to 0.6 nr per m adsorber surface and hour is passed. 3. The method according to items 1 and 2, characterized in that the electrostatic precipitator ash or flue dusts in quantities of 10 kg / nr wastewater to 150 kg / m wastewater are introduced. 4. The method according to item 1 to 3, characterized in that a pH lowering in the range 1.5 to 6.0 is set. 030062 / OS4S "Ά- ■ 5 · Process according to points 1 to 4 »characterized in that that, depending on the dyes in the wastewater, the following process steps are coupled: - Adsorption on raw xylitol, thermally or chemically activated xylitol, xylitol-containing waste products or. Teilverkokteia Ashexylite and downstream blocking with electrostatic precipitator as ehe or hugs deaf - upstream and downstream biological purification stage Flocculation with electrostatic precipitator ash or plug dust - upstream biological purification stage and downstream adsorption on activated xylitol, raw xylitol, By-products containing xylitol or partially coked ashexylite - upstream biological purification stage and downstream adsorption on raw xylitol, activated xylitol, xylite-containing waste products or partially coked ashexylite and flocculation with electrostatic precipitator ash or fly ash - Upstream biological purification stage and downstream flocculation with electrostatic precipitator ash or fly ash and downstream adsorption on crude xylite, activated Xylitol, waste products containing xylitol or partially coked ashexylitol - including 2 sheets of drawings - JD30062 / 0B45 C?