Plum pickle wastewater – Part 2: Information on volume and quality; seeking treatment processes
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Plum waste water: 1. It is highly concentrated, yellow-orange in color, contains suspended solids; its COD is as high as 150,000 mg/L, and the ammonia nitrogen level exceeds 2,000 mg/L. The volume of this water is 1 ton per day. 2. Low-concentration cleaning water, transparent, containing suspended solids; COD is 1000 mg/L, ammonia nitrogen is almost 0, and the volume of water used is 6 tons per day. I conducted a small experiment on my own: high-concentration wastewater cannot be coagulated and settled, let alone decolorized, as it contains sugars, salts, edible acids, and other additives. I tried Fenton’s reagent as well, but it didn’t work; coagulation did not occur. Please give some advice.
What are the main pollutants in high-concentration wastewater? How much salt is there, and what type of salt is it? What’s the pH? Do you have the BOD data?
Marinating is a method of processing aquatic products that uses salt as the main preservative. Food processing enterprises that engage in pickling and marinating discharge untreated production wastewater with high pollution levels (COD, BOD, SS) and high salt content directly. This not only pollutes the natural environment and leads to regional salinization of the soil, but it also results in serious waste of water resources and raw materials used in production, such as table salt. Due to the high pollution levels in the wastewater (COD, BOD, SS) and its high salt content, biological degradation cannot be used in the treatment process ； Common physical and chemical treatment processes such as flocculation and sedimentation cannot be used either. For the high levels of pollution in pickling wastewater (COD, BOD, SS), ozone oxidation can be used as a treatment method: This approach utilizes the strong oxidizing power of ozone to oxidize and break down the pollutants in the wastewater into less toxic or non-toxic compounds, thereby purifying the water quality. It can not only reduce BOD and COD in water, but also perform functions such as decolorization, deodorization, odor removal, sterilization, and algicidal action; therefore, this treatment method is receiving increasing attention. For pickling wastewater with different salinities, the following various treatment processes can be employed: 1. When the salinity is less than 2 g/L, it may be possible to treat saline wastewater through acclimatization. However, the salinity concentration for acclimatization must be increased gradually, acclimating the system in stages to the desired salinity level. A sudden high-salt environment can cause the failure of acclimatization and a delay in initiation. 2. Dilute the salinity of the incoming water. Since high salt levels act as inhibitors and toxins for microorganisms, diluting the influent water to keep its salinity below the toxic threshold will prevent inhibition in biological treatment. This method is simple, easy to operate, and easy to manage ； Its disadvantages are an increase in processing scale, higher infrastructure investment, increased operating costs, and water waste. 3. When the salinity is greater than 2 g/L, evaporation concentration for desalination is the most economical and effective feasible method. Other methods, such as those involving the cultivation of salt-tolerant bacteria, face difficulties in practical industrial application.