Main points of winter management of pretreatment system

2020/12/25

During the operation of sewage treatment plants in winter, the characteristics of high sewage concentration, low water temperature and relatively small water volume are common. The proportion of industrial sewage has increased. The control of the source of inflow should be strengthened. Once the control determines the abnormality of high influent pollutants In case of the situation, emergency measures should be taken, and evidence should be left to communicate with the competent authority in time.

Mechanical grille:

The most problematic response during winter operation is the mechanical grille, which is characterized by frequent failures, inability to operate normally, and low slag removal efficiency, which reduces the cross-sectional area of the grille. The liquid level in front of the grille is too high, causing water blocking and directly affecting the water intake. The flow rate and the unblocked drainage pipelines in the factory area caused frequent openings of water pumps, poor drainage in various production workshops, and water leakage in the drainage pipelines in the factory. If it is an outdoor grille machine, the grille is easy to freeze, so that the distance between the grille bars becomes smaller and the rake teeth of the grille are deformed and broken, which affects the operation effect. The main reasons for the failure of the mechanical grille in winter are: high humidity, high humidity, and low night temperature in the operating room in winter, which cause the mechanical grille limit switch to freeze and make the mechanical grille unable to work normally.

In view of this problem, the characteristics of winter operation can be fully considered in the structure of the house between the grids and the characteristics of the equipment, such as high humidity inside the house and serious corrosion of the control cabinet. Consider adopting technical measures of natural ventilation in the structure of the house, and add a ventilation fan on the top of the house to ensure that the moisture in the treatment facility can be naturally discharged from the roof and reduce the number of icing of the limit switch. For outdoor units, high water level operation should be adopted as much as possible during operation, so that the grid is immersed in water to reduce the possibility of icing and ensure the normal and stable operation of the mechanical grid.

It is recommended that the sewage treatment plant in the northern alpine region should fully consider indoor ventilation when the mechanical grille is operating in winter to prevent equipment from freezing. While maintaining ventilation, attention should be paid to the secondary heat preservation and reinforcement of the vents to prevent the fans from failing. When it is turned on, cold air enters the room and freezes heating facilities and process equipment.

Conveyor:

When the belt conveyor is running in winter, the belt becomes hard due to the low temperature, often runs off and is difficult to adjust, causing slag and mud leakage.

During operation in winter, due to low temperature, freezing of sewage and sludge often occurs, causing blockage and seriously affecting normal production and operation. In view of this problem, it is recommended to replace the original belt conveyor with a screw conveyor. In addition, full consideration is given to changing the semi-indoor conveying device and outdoor conveying equipment to mechanical conveying. If the outdoor part of the screw conveyor has been frozen, please pay attention to the operation after the ice formed by the sewage or sludge melts. When shutting down, drain the sewage before shutting down. The grid slag, scum, and dehydrated sludge output in each workshop should be cleaned and transported in time to avoid freezing.

Aeration and sand settling room (sludge dewatering room):

In order to maintain indoor temperature, the doors and windows of the aeration and sand settling rooms and sludge dewatering rooms that operate indoors in winter are closed. The ventilation conditions are poor and the water vapor in the workshop is high. The electrical cabinets in the workshop often cause electrical appliances due to high humidity. Corrosion and short circuit of components cause great safety production hazards. It can be adopted to increase the power of the induced draft equipment in the workshop, increase the number of induced draft equipment, and adopt the intermittent opening of the induced draft equipment to maintain indoor ventilation and ensure that the indoor temperature does not drop significantly. In addition, the cable trench and the indoor drainage ditch are arranged separately to prevent moisture from escaping to the distribution cabinet through the drainage ditch, which greatly reduces the failure rate of electrical equipment.