Factors Affecting Microbial Activity in Sewage Treatment

Microorganisms are needed in the process of sewage treatment, but the activity of microorganisms will be affected in the process of sewage biochemical treatment. Factors affecting microbial activity can be divided into two categories: matrix and environment. The following editor will introduce the factors that affect the microbial activity of sewage treatment.

Substrates include nutrients, such as organic compounds mainly composed of carbon, that is, nutrients such as carbon sources, nitrogen sources, and phosphorus sources, as well as trace elements such as iron, zinc, and manganese; in addition, some toxic and harmful chemicals such as phenol Classes, benzene and other compounds, also include some heavy metal ions such as copper, cadmium, lead ions and so on. Environmental factors mainly include:

1. Temperature. The influence of temperature on microorganisms is very extensive. Although some types of bacteria are active in high temperature environments (50°C to 70°C) and low temperature environments (-5 to 0°C), most microorganisms in sewage treatment are the most The suitable temperature range for growth is 20-30°C. In a suitable temperature range, the physiological activities of microorganisms are vigorous, and their activity increases with the increase of temperature, and the treatment effect is better. Beyond this range, the activity of microorganisms will deteriorate, and the biological reaction process will be affected. Generally, the upper and lower limits for controlling the progress of the reaction are 35°C and 10°C, respectively.

2. pH value. The most suitable pH range for microorganisms in the activated sludge system is 6.5-8.5. An environment with too strong acidity or alkalinity is not conducive to the survival and growth of microorganisms. The treatment effect deteriorated dramatically.

3. Dissolved oxygen. For aerobic biological reactions, it is very important to maintain a certain concentration of dissolved oxygen in the mixture. When the dissolved oxygen in the environment is higher than 0.3mg/l, both facultative bacteria and aerobic bacteria perform aerobic respiration; Oxygen respiration, most of the aerobic bacteria basically stop breathing, while some aerobic bacteria (mostly filamentous bacteria) may grow well, and often lead to sludge bulking after they dominate the system. Generally, it is advisable to keep the dissolved oxygen at the outlet of the aeration tank at about 2mg/l, if it is too high, the energy consumption will be increased, which is not economical.

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