Causes: The sedimentation tank has dead corners, where local accumulation of sludge becomes anaerobic, producing CH4 and CO2. Bubbles attach to the sludge particles, causing them to float, resulting in higher ammonia nitrogen in the effluent; the return ratio is too small, and the sludge return is not timely, leading to anaerobic conditions. Solutions: If there are dead corners in the sedimentation tank, maintaining the system in a state of higher dissolved oxygen can alleviate the problem. A fundamental solution requires structural modifications to the dead corners; increasing the return ratio can prevent sludge from staying in the sedimentation tank for too long.

Analysis of the causes of large black sludge floating in the sedimentation tank

When the sedimentation tank processes various types of industrial wastewater or domestic sewage, the phenomenon of large black sludge floating may occur. This phenomenon can have multiple causes, involving aspects such as processes, water quality, and management.

1. Sludge characteristics

Black sludge usually contains a high amount of organic matter and microorganisms. Under specific conditions, these substances can react, producing gases that cause the sludge to float. Additionally, heavy metals in the sludge may also form denser precipitates, leading to the floating phenomenon.

2. Changes in water quality

Changes in the water quality entering the sedimentation tank, such as excessively high concentrations of suspended solids or the presence of certain specific substances, may lead to changes in the characteristics of the sludge, thereby triggering floating.

3. Operational management issues

The operational management of the sedimentation tank is also an important factor affecting sludge floating. For example, if sludge is not discharged in a timely manner, it can lead to excessive sludge in the sedimentation tank; improper control of aeration may also affect the settling performance of the sludge; furthermore, improper dosing of chemicals or insufficient dosing may also lead to sludge floating.

4. Equipment issues

If there are problems with the equipment in the sedimentation tank, such as a malfunction of the stirring equipment leading to excessively fast local flow rates, this may also prevent the sludge from settling effectively and cause it to float. Additionally, issues like pipeline leaks may also lead to fluctuations in water quality, thereby affecting the characteristics of the sludge.

5. Comprehensive reasons

In summary, the floating of large black sludge may be the result of multiple factors acting together. To address this issue, it is necessary to comprehensively consider water quality, processes, equipment, and management. Specific measures include regular monitoring of water quality, optimizing operational management, inspecting and maintaining equipment, and rationally dosing chemicals. At the same time, regular dredging of the sedimentation tank is needed to maintain its good operational state.

To effectively prevent and solve the problem of large black sludge floating in the sedimentation tank, it is necessary to strengthen on-site management and training in operational skills, as well as to introduce advanced technologies and equipment for water quality monitoring and process control. Only in this way can the stable operation of the sedimentation tank be ensured, thereby achieving effective wastewater treatment.