Sludge expansion

For: long-term low sludge load and insufficient nutrient salt

If the degree of expansion has not yet reached a high degree of expansion, adjusting the sludge load and replenishing a sufficient amount of nutrient salt can gradually return the sludge to a normal state.

Among them, the adjustment of sludge load should be based on increasing the amount of sludge, supplemented by increasing the influent load, so that the sludge load can reach 0.2 KGBOD/ KGMLSS.d or above. Under the premise of satisfying the demand of microbes for nutrients such as N and P, the load can reach a reasonable interval, which can promote the proliferation of bacteria micelles, and the growth rate is higher than that of filamentous bacteria, thereby inhibiting sludge expansion; At the same time, increasing the discharge of excess sludge can not only improve the sludge load of the system, but also discharge a large number of filamentous bacteria, which is beneficial to the advantage of the bacteria micelles in the growth of activated sludge during the optimization and adjustment process. status.

For: high water temperature, low dissolved oxygen
If the degree of expansion has not yet reached a high degree of expansion, the sludge can be gradually returned to a normal state by adjusting the sludge load while increasing the amount of aeration.

If the oxygen supply amount is difficult to increase greatly due to equipment reasons or water temperature, the adjustment of the sludge load can be achieved by increasing the sludge discharge and reducing the sludge concentration of the aeration tank.

Since the decrease in sludge concentration is beneficial to reduce the demand for oxygen, the increase in the ratio of food to food is beneficial to the utilization efficiency of oxygen.

For: low pH
In this case, the sludge load is often insufficient. If the degree of expansion has not reached a high degree of expansion, in addition to adjusting the pH value of the influent water, adding liquid alkali to the aeration tank, increasing sludge discharge and increasing sludge load It is a necessary adjustment tool.

Through process adjustment, the required time period is longer, and the effluent water quality deteriorates for a long time and even causes substandard discharge, which is not worth the loss for the enterprise. At this point, the expansive sludge in the system can be emptied, and it is a reasonable choice to inoculate new activated sludge for re-cultivation.

In addition, it should be noted that people often do this: adding inert substances, bacteriostatic agents to the system and raising the pH to above 10 to crush filamentous mycelium and kill filamentous fungi. These measures are not recommended because not only the high cost, but also the inadvertent operation will lead to further deterioration of the system’s effluent, and eventually have to choose to re-culture the activated sludge, extending the processing cycle.