A beginner shares some information given to me by an experienced person (1)

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1. How much does it cost to disinfect each load of wastewater using sodium hypochlorite? Answer: The price of sodium hypochlorite with a concentration of 10% is 700 yuan per ton. The cost of treating wastewater varies depending on the dosage used; when the dosage is 20 mg/l and the contact time is 30 minutes, E. coli cannot be detected. 2. How should sludge bulking in a wastewater treatment plant be addressed? Answer: If sludge bulking occurs in this plant, using ferric chloride for treatment can only improve the sedimentation properties of the sludge. Since treating sludge bulking solely with chemicals is generally not appropriate, it is possible to discharge more sludge after the phenomenon of sludge bulking disappears, then reintroduce water for cultivation and observe carefully. It is worth noting in particular that when a wastewater treatment plant has an anaerobic process section, special attention must be paid to whether there are any abnormalities in SVI; if such abnormalities occur, appropriate measures should be taken to prevent sludge bulking. 3. Do zinc ions and iron have an impact on the biochemical tank? Answer: Iron ions can poison the treatment system in the digestion tank, and the effluent cannot meet the standards for a certain period of time. The symptoms of iron ion poisoning in the system include: ① sludge removal while the machine is running, with the sludge turning red in color. ②The DO in the activated sludge system is low. ③The effluent parameters exceed the limits, and the biological community is inactive. 4. The influent water contains a high amount of oil, resulting in large areas of suspended dead sludge in both the anoxic and aerobic zones of the biochemical tank. How should this be removed? Answer: This phenomenon should be addressed by flushing the tank regularly with water (installing a recirculated water spraying system can help reduce costs), and by increasing the amount of sludge removed. After this issue is resolved, and after the 15th day of the first lunar month, once the ammonia nitrogen level in the wastewater treatment plant is stable and meets the required standards, the amount of sludge discharged should be increased, especially when foam begins to accumulate as a result of biological activity. 5. In winter, the ammonia nitrogen level in the wastewater treated by the plant is relatively low, but it exceeds the permissible limits by March. The volume of sludge increases little, so less sludge is discharged in March; as a result, dead sludge starts to float on the surface of the tanks in April. After that, whenever the ammonia nitrogen level exceeded the standard in March each year, the factory increased the amount of sludge discharged, and the ammonia nitrogen level quickly returned to the acceptable range. What conclusion can be drawn from this? Answer: Based on the description, it cannot be concluded that increasing the sludge discharge volume will reduce the ammonia nitrogen content in the effluent; it only indicates the uncertainty regarding whether the wastewater treatment plant’s water quality meets the standards. There are various reasons for ammonia nitrogen not meeting the standards.