1: As the temperature rises, mud and floating mud always appear in the secondary sedimentation tank
In summer, mud and floating mud in the secondary sedimentation tank are common in urban sewage and industrial sewage treatment. It not only affects the perception of sewage treatment, but also easily leads to an increase in effluent SS, and even causes the effluent to exceed the standard.
In summer, the settling performance of activated sludge decreases, the stratified sedimentation rate decreases, and sludge turnover is prone to occur in the secondary sedimentation tank, resulting in an increase in effluent SS.
As the temperature rises, the metabolic growth capacity of microorganisms accelerates and the oxygen consumption increases. Anaerobic or denitrification reactions are prone to occur in the secondary sedimentation tank, producing gas and sludge floating.
2: Why is it easy for sewage to exceed the phosphorus standard in summer?
When the temperature is high in summer, the activity of bacteria is strong, and the speed of phosphorus accumulation by polyphosphate bacteria will also increase. At this time, the sludge flow rate is accelerated and the sludge age is short, resulting in the inability of polyphosphate bacteria to remove phosphorus components in time during the anaerobic stage. When the remaining polyphosphate bacteria that have not completely released total phosphorus enter the secondary sedimentation tank with the sludge, the effluent phosphorus concentration will rise. At this time, if the amount of chemical agents is not increased to reduce the phosphorus concentration in the effluent, the water quality will easily exceed the standard.
3: The temperature is too high, the equipment overheats quickly, the heat dissipation is slow, and the normal operation of the equipment is affected
In addition, the water pump and fan are under high load for a long time in summer, which is one of the common faults. In addition, some electronic components, sensors and pipes are often damaged by high temperature.
Take the aeration blower as an example. In the hot summer, the blower will alarm and shut down due to the high temperature of the lubricating oil caused by cooling problems, and will automatically reduce the air volume for safety reasons. This not only affects the sewage treatment effect, but also causes serious damage to the operation of the blower and reduces its service life.
Therefore, in hot weather, sewage treatment plant staff should do a good job of ventilation and cooling and mechanical equipment safety supervision in advance; closely monitor the operation of the equipment, check the equipment cooling system and heat dissipation, and if the equipment has heat dissipation problems, install axial flow fans in time to take forced ventilation measures; replace and empty the lubricating oil of the conveying equipment in time, and deal with abnormalities in time; prepare equipment high temperature emergency plans in advance, do their best to ensure the safe and reliable operation of the equipment, ensure the stable operation of the sewage treatment plant mechanical equipment, and avoid high temperature damage to the equipment.
4: Two-stage AO process, the water temperature of the aerobic pool in summer is 38-39°C, what cooling measures are there?
Hot weather and high ambient temperature will inevitably increase the water temperature of the aerobic pool. To reduce the pool water temperature, it is necessary to control the inlet water temperature and reduce the ambient temperature. Installing a cooling tower at the front end of the aerobic pool can effectively reduce the inlet water temperature, ranging from 7 ~ 8℃ to 2 ~ 3℃.
The main aeration pipe can also be treated by sprinkling water to reduce the temperature caused by the fan heating. When the amount of water to be treated is not large, heat exchangers, ice throwing and other methods can also be considered. At present, many sewage treatments have taken measures to cover and deodorize, which will cause heat accumulation. When the temperature rises to 50℃, aerobic digestion and nitrification will stop, so cooling measures such as water spraying and cooling fans need to be taken in advance.
5: What should I do if the dissolved oxygen in the aeration tank becomes low in hot weather?
In summer, the temperature is too high, and oxygen is not easily soluble in water, which often leads to insufficient oxygen supply in the water, and microorganisms are prone to hypoxia. At the same time, within a certain range, it will accelerate the metabolic growth rate of microorganisms, increase oxygen consumption, and further aggravate the degree of hypoxia in the water body.
Therefore, in actual production operations, attention should be paid to changes in water temperature, especially sudden increases in water temperature. In order to prevent industrial wastewater with too high water temperature from having an adverse effect on aerobic biological treatment, cooling treatment should be carried out.
6: How to reduce the incidence of safety accidents in summer and reduce production safety hazards?
In some closed and limited spaces, microbial metabolism consumes a lot of oxygen and releases toxic and harmful gases. Therefore, sewage treatment operators must take ventilation pretreatment measures when working in limited spaces. At the same time, we should strengthen the prevention of flammable and explosive items, conduct self-inspections of distribution rooms, warehouses, oil depots and other areas prone to explosions and fires, and promptly discover and deal with hidden dangers. We should also conduct a comprehensive inspection of fire-fighting facilities such as fire extinguishers and fire hydrants to ensure that they function properly.