Wastewater treatment is the process of purifying wastewater to meet the water quality requirements for drainage or reuse. With the increasing shortage of water resources and the worsening of water pollution, sewage treatment has become an important way to protect water resources. There are various sewage treatment processes, and how to become a sewage treatment expert requires the following knowledge to be seen!

1. What is the biological wastewater treatment method?

Biological treatment is the use of microorganisms to adsorb, decompose, and oxidize organic matter in wastewater, degrading unstable organic matter into stable and harmless substances, thereby purifying wastewater. Modern biological treatment methods can be divided into two categories based on the different microorganisms involved, aerobic oxidation and anaerobic reduction. The former is widely used for treating urban sewage and organic industrial wastewater. Aerobic oxidation has a wide range of applications, including many techniques and structures. There are various processes and structures such as biofilm method (including biological filtration tank, biological turntable), biological contact oxidation, etc. Activated sludge method and biofilm method are both artificial biological treatment methods. In addition, there are natural biological treatment methods for farmland and ponds, namely irrigated fields and biological ponds. Biological treatment is a widely used sewage treatment method due to its low cost.

2. What is the total amount of wastewater treatment or BOD5 removal and treatment quality?

◆ Sewage treatment capacity or total BOD5 removal amount: The total daily sewage flow rate (in m3/d) entering the sewage treatment plant can be used as an indicator of the sewage treatment capacity. The total amount of BOD5 removed daily can also be used as an indicator of the treatment capacity of the sewage plant. The total amount of BOD5 removed is equal to the product of the difference between the treated flow rate and the inlet and outlet water BOD5, in kg/d or t/d.

◆ Treatment quality: The secondary sewage treatment plant uses the factory's BOD5 and SS values as the treatment quality indicators. According to the newly formulated effluent discharge standards for sewage treatment plants, the BOD5 and SS of the effluent from secondary sewage treatment plants are both less than 30mg/L. The quality of treatment can also be measured by removal rate. The removal rate is determined by subtracting the inlet concentration from the outlet concentration and dividing it by the inlet concentration. Ammonia nitrogen, TP effluent value or removal rate should also be used as treatment quality indicators.

3. What is pH value and its indicative significance?

PH represents the acidity and alkalinity of wastewater. It is the logarithm of the reciprocal of hydrogen ion concentration in water, ranging from 0 to 14. If the pH value is 7, the water is neutral. If it is less than 7, it is acidic. The smaller the value, the stronger its acidity. If it is greater than 7, it is alkaline. The larger the value, the stronger its alkalinity. The pH value in sewage has a certain impact on pipelines, water pumps, gate valves, and sewage treatment structures. The pH value of sewage treatment plants, mainly composed of domestic sewage, is usually between 7.2 and 7.8. Excessive or insufficient pH values can indicate the entry of industrial wastewater. A low value can corrode the pipeline and pump body, and may cause harm. For example, sulfides in wastewater can generate H2S gas under acidic conditions. High concentrations can cause headaches, runny nose, suffocation, and even death during operation. Therefore, it is necessary to strengthen monitoring, identify sources of pollution, and take countermeasures to detect a decrease in pH. Meanwhile, the allowable pH range for biochemical treatment is 6-10, and either too high or too low can affect or disrupt the biological treatment.