What is a disadvantage of chemical phosphorus removal in wastewater treatment?

The selection of creating a high volume of additional sludge as a disadvantage of chemical phosphorus removal highlights a significant operational impact associated with this treatment method. In chemical phosphorus removal, coagulants, such as iron or aluminum salts, are added to wastewater to precipitate phosphorus. While this process effectively reduces phosphorus levels, it also leads to the formation of additional sludge.

This additional sludge can become a challenge for wastewater treatment facilities, as the increased volume requires more resources for handling, processing, and disposal. Dealing with this extra sludge can strain the plant's capacity and operational budget, making it a critical drawback to consider when evaluating treatment options.

The other choices may reflect some benefits of phosphorus removal processes, such as cost-effectiveness or reduced sludge volume, but they do not address the core disadvantage linked to the added sludge production, which is a key consideration in wastewater management.