Treatment device and method for waste liquid generated from COD value determination

Abstract

The invention discloses a treatment device and method for waste liquid generated from COD value determination, relates to the technical field of sewage treatment, in particular to a waste liquid treatment device and method, wherein waste liquid is generated in the process of determining COD value in a water sample through a dichromate method and generated in the operation process of a COD online analyzer through a rapid digested spectrophotometry method. The device comprises an automatic control part and a water treatment part, the automatic control part and the water treatment part are installed in an integrated cabinet, the device can automatically treat the waste liquid generated by determining the COD value in the water, solid residues are automatically collected, and waste liquid treatment amount is automatically recorded. The treatment device is convenient to install, easy to operate, capable of effectively reducing environmental pollution and wide in application prospects.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a waste liquid produced by a water quality laboratory for measuring the COD value in a water sample by a dichromate method, and a waste liquid produced during the operation of a fast digestion spectrophotometric COD online analyzer. Liquid treatment device and waste liquid treatment method. Background technique [0002] The so-called COD is chemical oxygen demand, which refers to the amount of oxidant consumed when a certain strong oxidant is used to treat water samples under certain conditions. It is an index indicating the amount of reducing substances in water and reflects the quality of water. an important indicator of . The so-called dichromate method is based on GB / T 11914-1989, the determination of water quality chemical oxygen demand. The dichromate method [S] is a standard method for measuring the COD value in water; According to HJ399-2007, Determination ...

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Problems solved by technology

The disadvantages of this treatment method are: there is no removal link for hexavalent chromium; it is difficult to make the concentration of all heavy metals in the waste liquid reach the discharge standard by a single neutralization method with sodium hydroxide, and there is no advanced treatment plan; solid-liquid separation efficiency low, long processing cycle

The disadvantage of this method is that although the concentration of heavy metals in the waste liquid is within a certain range, it is not a fixed concentration value, and there will be certain fluctuations. Therefore, quantitative dosing of Na 2 S·9H 2 O, due to the change of the initial concentration of heavy metals in the waste liquid, excessive or insufficient dosing will affect the removal rate of heavy metals. Without an advanced treatment plan, it is difficult to ensure that the treated waste liquid can reach the standard stably with this method; Sodium sulfide (Na 2 S·9H 2 O) There is no follow-up treatment plan for excess sulfide introduced due to excess; the solid-liquid separation efficiency is low, and there is no specific solid residue collection method; the treatment period is long

The defect of the described equipment is: the waste liquid produced by fast digestion spectrophotometry to measure the COD value in water is a strong acid solution, and the pH value is less than 2.5. In addition, according to HJ399-2007, the fast digestion spectrophotometry for water quality chemical oxygen demand [ S] measurement principle, the concentration of hexavalent chromium in the waste liquid is within a certain range, and the content is very little, it is suitable to directly add quantitative reducing agent to carry out the reaction that hexavalent chromium is reduced into trivalent chromium, and the described equipment adopts the method of adjusting the pH value Then adjust the orp value by means of dynamic dosing (orp value is the abbreviation of English Oxidation-Reduction Potential, which represents the oxidation-reduction potential of the solution

The orp value is a measurement indicator of the oxidation-reduction capacity of an aqueous solution, and its unit is mv), which increases the equipment and increases the difficulty of control, which is not the best solution; there is no recovery link for the available component silver ions; a large amount needs to be added when adjusting the pH value Sodium hydroxide, the generated sodium sulfate is about 500g / L, and the saturated solution concentration of sodium sulfate is 194g / L at 20°C, so there are a large number of sodium sulfate crystals (Na 2 SO 4 10H 2 O) separate out, increase the amount of residue, increase the processing cost of solid waste, described device does not solve this problem; There is no emergency treatment measure after liquid leakage occurs under the failure situation, easily causes the pollution of equipment surrounding environment; The measurement link of the liquid treatment volume is not convenient for the supervision of the waste liquid treatment

[0008] So far, no standardized waste liquid treatment methods and treatment devices have been applied in practice

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