Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/025—Thermal hydrolysis
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/30—Active carbon
  • C01B32/354—After-treatment
  • C01B32/36—Reactivation or regeneration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the invention relates to a process for the treatment of waste water containing organic and inorganic compounds, preferably from epichlorohydrin synthesis, which contain adsorbable organic halogen compounds.
• waste water is obtained which, in addition to small amounts of the reaction product and the starting products, contains further organic, organochlorine and inorganic compounds as by-products of the synthesis.
• This wastewater can contain the following compounds.
• the organochlorine compounds contained in the waste water contribute to the sum parameter AOX (adsorbable organic halogen compounds) of the waste water.
• Wastewater containing such halogenated organic compounds represents a particular problem in wastewater treatment, since the removal of these substances is technically very complex and therefore often uneconomical because of the high stability of the covalent carbon halide bonds, especially in the case of sp 2 -bonded halogens.
• REPLACEMENT BLA ⁇ Wastewater is a chemical-physical and biotechnological process.
• Processes for the chemical-physical removal of halogen-organic compounds from waste water are used for main or preliminary cleaning with subsequent biochemical treatment of the waste water.
• Activated carbon which is loaded with organic ingredients from waste water from epichlorohydrin production can be treated by the known method of treatment with steam or hot inert gases, such as. B. nitrogen, not regenerate sufficiently.
• halogenated organic compounds in the biochemical purification stage of a sewage treatment plant also poses various problems. On the one hand, many of these compounds are difficult or not at all amenable to biological decomposition by microorganisms; on the other hand, the use concentrations of AOX-producing substances in the waste water must not be high and should have largely constant values. In addition, the volume of the activated sludge in such plants is large, and the accumulation of the organic halogen compounds in the sludge represents a further problem, so that chemical-thermal processes are often used to destroy organohalogen compounds in waste water. These include the so-called wet-oxidative processes, in which decomposition of halogenated organic compounds in an oxidizing atmosphere at high temperatures and considerable pressures. Connections are made.
• Metals, metal hydrides or metal alcoholates are used alone or in combination with a strong base as substances which have a high reactivity with organically bound halogens.
• Disadvantages of the known chemical-thermal processes are, in addition to their relatively high costs, the often long reaction times (often more than 10 hours) and the often only moderate degradation rates.
• the object of the invention was therefore to provide a continuous process for the treatment of waste water contaminated with organic and inorganic substances, preferably from epichlorohydrin synthesis, with which a reduction in the AOX content and the COD value is possible.
• the invention therefore relates to a process which is characterized in that the waste water is subjected to a thermal-alkaline treatment, an adsorption on activated carbon and a biological treatment.
• REPLACEMENT BLA ⁇ (RULE 26) is subjected to regeneration, the regeneration of the activated carbon being part of the process while maintaining the continuous process flow.
• the wastewater emerging or discharged from the reaction vessel which contains adsorbable organic halogen compounds in an amount of more than 10 mg / 1, preferably more than 20 mg / 1 and a total content of dissolved organic substances of more than 0.10 g / 1 and has a pH of 10 to 14, preferably 11 to 14 (measured at room temperature), or is adjusted to such a pH, is introduced into and / or passes through at least one reactor, a temperature of more than 75 ° C, preferably 85 ° C to 185 ° C, a pressure of at least 1 bar (absolute), preferably 1 to 10.5 bar (absolute), and a residence time of at least 0.5 hours, preferably 1 to 8 hours in which the reactor is set or maintained.
• a targeted AOX degradation rate is possible by adhering to or setting the respective sets of parameters.
• the rate of AOX degradation depends, among other things, on the starting AOX and on the structure of the AOX-producing compounds.
• the following parameter sets should preferably show embodiments of the chemical-thermal treatment stage.
• alkali and / or alkaline earth hydroxide preferably an aqueous calcium hydroxide and / or sodium hydroxide solution
• the pH value can also be adjusted with an appropriate amount of alkali carbonate and / or alkali hydrogen carbonate, preferably an aqueous sodium carbonate and / or sodium hydrogen carbonate solution.
• the wastewater emerging from the synthesis reactor in particular in the case of excess lime milk used as an alkaline agent in the production of epichlorohydrin, contains suspended solids, which can lead to disruptions in the further course of the process, it is advantageous, if appropriate, to precede the wastewater to be at least partially freed from the suspended solids during and / or after the individual treatment stages by separating or separating these solids by appropriate conventional measures.
• This is preferably done by chemical reaction, e.g. B. suspended calcium hydroxide is dissolved by adding hydrochloric acid and / or by mechanical separation processes such as filtration or sedimentation.
• the wastewater to be treated is fed in
• ERS ⁇ ZBL ⁇ (RULE 26) Current at the top of the reactor or reactors and the treated waste water are discharged at the bottom of the reactor. Feeding from below with upward flow could lead to clogging problems due to the suspended solids.
• a flow tube or tube reactor can also be used for the continuous implementation of the thermal-alkali treatment stage, a flow velocity of more than 4 m / sec in the flow tube or tube reactor. is set. The flow rate is preferably 8.5 m / sec.
• the organic compounds contained in the waste water are partially dechlorinated and / or dehydrochlorinated by this treatment.
• This thermal-alkaline treatment is followed by a treatment with activated carbon.
• the waste water leaving the thermal-alkaline treatment is first cooled to a temperature ⁇ 35 ° C. and adjusted to a pH of 4 to 12, preferably 4.5 to 8 (measured at room temperature).
• the pH is adjusted in a manner known per se using acid, preferably by adding hydrochloric acid.
• an activated carbon bed can preferably be alternately regenerated and, after the regeneration, can be fed with the waste water to be cleaned again.
• the waste water passes through the activated carbon bed with an average residence time of 3 to 15 hours.
• an activated carbon fixed bed is used. The following are to the nature of the activated carbon Conditions.
• An activated carbon is preferably used, the specific surface area of which is 800 to 1200 m 2 / g and which has a preferred grain diameter of 0.8 to 4 mm.
• the regeneration of the activated carbon loaded with adsorbable organochlorine compounds is part of the overall process and thus the disposal of the activated carbon is unproblematic.
• the reactor which contains the loaded activated carbon from the process, is rinsed with deionized or partially ionized water and then the activated carbon is mixed with sodium hydroxide solution at a concentration of 0.5 to 5 mol / 1, preferably 1 mol / 1 at 75 to 185 ° C, preferably at 95 to 170 ° C, about 0.5 to 7 hours, preferably 1 to 4 hours, thermally treated.
• the activated carbon is cooled to a temperature of> 35 ° C, washed with deionized or partially ionized water or first washed with deionized or partially ionized water and then cooled to a temperature of 35 ° C and is thus again available Waste water treatment available.
• the sodium hydroxide solution is used several times to increase the economy of the process. It has proven advantageous to use the sodium hydroxide solution 2 to 5 times to regenerate the activated carbon.
• the sodium hydroxide solution is preferably reused until the pH of the sodium hydroxide solution (measured at room temperature) is ⁇ 13.
• the activated carbon is used after every 10 to 30 loads, in particular after 15 to 25 loads and / or as required, i.e. H. after getting worse
• SPARE BLADE (RULE 26) The adsorption performance with 5 to 20 dm 3 hydrochloric acid (with a concentration of 0.5 to 5 mol / 1 preferably 0.7 to 3 mol / 1) per kilogram of activated carbon, preferably 8 to 15 dm 3 hydrochloric acid per kg activated carbon, one being treated
• the residence time of the hydrochloric acid in the activated carbon is from 3 to 15 hours, preferably from 5 to 12 hours.
• This additional hydrochloric acid treatment has proven to be advantageous in the treatment of waste water from epichlorohydrin production which contain calcium ions.
• the activated carbon is also rinsed with deionized or partially ionized water.
• the rinsing water, the used sodium hydroxide solution and the hydrochloric acid which may be used can be fed to the biological cleaning stage after neutralization, if necessary.
• the waste water leaving the epichlorohydrin synthesis can be subjected directly to the activated carbon treatment.
• the pH of the waste water must be set to a value of 4 to 12, preferably 4.5 to 8 (measured at room temperature). The pH is adjusted in a known manner by adding acids. After the solids have been separated off, the waste water is fed to the biological treatment.
• the biological treatment can be carried out in aerobic or anaerobic operation, preferably under aerobic conditions in the activated sludge basin.
• REPLACEMENT SHEET (RULE 26)
• the wastewater which has a pH of 7 to 11, preferably 7.5 to 10.5, or is adjusted to such, is introduced into the biological treatment stage.
• the pH is adjusted in a known manner. It has proven to be advantageous to remove the solids from the solids by filtration or other known mechanical or chemical processes before they are discharged into the biological stage.
• a mixture of gram-positive bacteria with a share of 20 to 98% in the total biocenosis and gram-negative bacteria with a share of 2 to 80% in the total biocenosis is used.
• only gram-positive bacteria are used for the biological treatment of the waste water.
• bacteria of the type Clavibacter, Cellulomona ⁇ , Aureobaterium, Microbacterium, Curtobacterium, in particular bacteria of the type Clavibacter insidiosus / sepedonicum, Cellulomonas uda, Aureobacterium barkeri can be used.
• Gram-negative bacteria are preferably bacteria of the Alcaligenes type, in particular of the Alcaligenes xylosoxidans ssp. denitrificans used.
• the biological treatment stage is operated with an average residence time of 4 to 25 hours, preferably 7 to 18 hours, and a temperature ⁇ 35 ° C.
• the biomass content in the activated sludge basin can be 1 to 10 g / 1, preferably 2 to 6 g / 1.
• the biological treatment with the named species results in a significant reduction in the COD value by 80 to 95%.
• the activated carbon treatment can also take place after the biological treatment stage.
• waste water without being thermally treated, is subjected directly to the activated carbon treatment and then to the biological treatment. It is also possible that the wastewater is first treated thermally, then biologically and then with activated carbon.
• the thermal energy stored in the heated treated wastewater stream to a cooler wastewater stream that is still to be treated, the hot treated wastewater stream being cooled at the same time.
• a heat exchanger is used for this.
• the heat exchange is preferably carried out by a direct transfer of the thermal energy through relaxation and condensation, in that the hot waste water under steam is expanded, whereby in particular water vapor is generated which is introduced into a cooler waste water stream which is still to be treated and on which its thermal energy is transferred Gives off condensation.
• gases and / or vapors are released in the waste water to be treated, in particular water vapor loaded with the more volatile organic compounds. This is preferably returned to the epichlorohydrin synthesis reactor.
• Waste water from the epichlorohydrin production with an AOX content of approx. 40 mg / 1, a COD content of approx. 1000 mg / 1 and a pH value (measured at room temperature) of 12 was
• the activated carbon had a specific surface of approx. 900 m 2 / g and a grain diameter of approx. 1 mm.
• the mixture of microorganisms preferably contained bacteria of the Cellulomonas and Aureobacterium type.
• the AOX value of the wastewater could be reduced by more than 90% and the COD value of the wastewater by 90%.
• the loaded activated carbon from Example 1 was first rinsed with distilled water, then treated with 7 cm 3 sodium hydroxide solution (1 mol / 1) per g activated carbon for 3 hours at 160 ° C., then cooled to 30 ° C. and again with distilled water rinsed.
• the activated carbon thus regenerated was then used again in accordance with Example 1. Again the game 1 results regarding AOX and COD.
• the active carbon was treated with 14 cm 3 hydrochloric acid (concentration: 1 mol / 1) per g activated carbon at room temperature for 4 hours.
• the activated carbon was then rinsed with distilled water until this water had a neutral pH.
• Example 1 The activated carbon treated in this way was then used again in accordance with Example 1. The degradation results in AOX and COD mentioned in Example 1 were again achieved.

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• Life Sciences & Earth Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Microbiology (AREA)
• Biodiversity & Conservation Biology (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Inorganic Chemistry (AREA)
• Water Treatment By Sorption (AREA)
• Removal Of Specific Substances (AREA)

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Citations (7)

• 1993
  • 1993-11-23 DE DE19934339887 patent/DE4339887A1/de not_active Withdrawn
• 1994
  • 1994-11-12 WO PCT/EP1994/003761 patent/WO1995014639A1/de not_active Application Discontinuation
  • 1994-11-12 CN CN94193244A patent/CN1145612A/zh active Pending
  • 1994-11-12 CZ CZ961047A patent/CZ104796A3/cs unknown
  • 1994-11-12 EP EP95900727A patent/EP0730560A1/de not_active Withdrawn
  • 1994-11-12 PL PL31298594A patent/PL312985A1/xx unknown
  • 1994-11-12 JP JP51479395A patent/JPH09505237A/ja active Pending
  • 1994-11-12 KR KR1019960701480A patent/KR960704804A/ko not_active Application Discontinuation

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