Advanced treatment technologies for coking wastewater； COD
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This post was last edited by yzhang2010 on 2011-9-27 at 10:28. Currently, coking wastewater is generally pre-treated using conventional methods, followed by secondary treatment via biological dephenolization. However, even after the aforementioned treatment of coking wastewater, it remains difficult for parameters such as cyanide, COD, and ammonia nitrogen in the discharged wastewater to meet the specified standards. Therefore, developing deep treatment technologies that are simple to implement and cost-effective is an urgent issue that needs to be addressed in the treatment of coking wastewater at present. Based on years of experience in engineering, our company has developed a new advanced treatment process for coking wastewater. This process features stable operation, low investment requirements, and minimal space consumption. It not only resolves the persistent problem of difficulty in meeting discharge standards for coking wastewater, but also lays a solid foundation for the future reuse of such wastewater. Case Introduction 1: Overview This sewage treatment project is a advanced treatment facility for Station No. 2 of a coking group in Shandong, with a designed capacity of 360 cubic meters per day. The main work involved strengthening the existing biological treatment section for wastewater, so that the treated wastewater can meet the current discharge requirements. II. Design Basis and Standards 1. Water volume data provided by a coking group in Shandong and relevant design requirements ； 2. «Discharge Standards for Wastewater in the Peninsula River Basins of Shandong Province» (DB37/676-2007) ； 3. «Quality Standards for Wastewater Discharged into Urban Sewers» (CJ3082-1999) ； 4. «Code for Structural Design of Water Supply and Drainage Projects» (GBJ69-84) ； 5. «Steel Tower-Type Vessels» (JB/T4710-2005) ； 6. «Code for Design of Concrete Structures» (GBJ11-89) ； 7. «Code for Design of Foundations of Tower Equipment in Petrochemical Industry» (SH3030-1997) ； 8. «Code for Design of Industrial and Civil Power Supply Systems» (GB500052-92) ； III. Design criteria for inlet and outlet water and design scope 1. The quality of water entering the advanced treatment section is as follows: CODcr ≤ 200 mg/l, colority ≤ 200 times ； 2. The treated wastewater meets the following standards: CODcr ≤ 60 mg/l, colority ≤ 40 times ； 3. Design scope: The design scope of this project starts from the point where wastewater enters the hydrolysis acidification tank and ends at the outlet of the secondary sedimentation tank ； The sludge treatment section ends at the sludge belt conveyor. IV. Process Flow: The effluent from the secondary sedimentation tank flows by gravity into the pH adjustment tank, where acid is added under the control of a pH meter to adjust the pH of the wastewater to around 4-4.5 ； After the pH of the wastewater is adjusted, it is pumped from the pH adjustment tank to the oxidation reactor. Catalysts and oxidants are added to this reactor, where the wastewater undergoes thorough deep oxidation. Once the pH is adjusted to around 7, the wastewater flows automatically into the modified inclined plate sedimentation tank ； After suspended solids are removed in the wastewater inclined plate sedimentation tank, the wastewater flows by gravity into the newly built BAF; after treatment in the BAF, it flows by gravity into the clear water tank for discharge once it meets the required standards.
Reply to 1# zzmgsn: two questions: 1. Is it a micro-electrolysis unit? 2. What are the approximate operating costs?
Reply to 2#: I don’t drink alcohol. It’s not micro-electrolysis; it costs around 5 yuan, depending on the water quality
It is necessary to explain the specific processes and their parameters, as well as what level of performance should be achieved. Treating coking wastewater is not a problem; the real challenge lies in treating the water to meet Standard B, and this is extremely difficult. Many people claim to possess such technologies or have obtained certain patents, but there are no actual examples to prove it.
Reply to 4# cdpulin: Our process is Fenton – coagulation and sedimentation – BAF – ozone. Parameters? Since the water quality varies for each case, it’s not possible to disclose it
The last edit to this post was made by laoyang3815 on 2011-7-12 at 23:50. For the Fenton reagent method, the pH is adjusted to 4 using sulfuric acid; then ferrous sulfate and hydrogen peroxide are added. Coagulation and precipitation occur by adjusting the pH to 7, after which flocs are formed, and PAM is added for further precipitation. At this point, the biodegradability can be improved; it can be treated with an aerated biological filter to reduce BOD, followed by further decolorization using ozone. It’s a very simple process, but the Fenton reagent method is somewhat expensive, as acid and then alkali have to be added, and a large amount of chemicals are required. Ozone is cheaper, but its effectiveness isn’t very good.
The operating costs aren’t high; the COD value is low, so the amount of hydrogen peroxide needed is naturally very small
The processing cost is not low. Hydrogen peroxide is used at the front and ozone at the back; aside from oxidizing COD, how is NH3-N treated – is it also oxidized?
For coking wastewater, it is still very difficult for the majority of enterprises to achieve an inlet water level with CODcr≤200mg/l and a colority of ≤200 times. The cost of Fenton oxidation + BAF + ozone oxidation is definitely high; it’s already not bad to manage it at 5 yuan.