Sludge Processing

The purpose of primary and secondary treatment is to remove as much organic solids from the liquid as possible while concentrating solids in a much smaller volume for ease of handling and disposal. Primary sludge has a typical solids content of 4 – 6 percent.

Sludge Processing reduces the solids content of this sludge through biological processes and removes more of the liquid content of it prior to disposal. The overall sludge processing investment cost at the typical wastewater treatment plant is about one-third of the total investment in the treatment plant. However, based on the individual wastewater treatment plant‘s processing system, operating expenses in sludge processing typically amount to even a larger portion of the total plant operating costs. To reduce plant operating costs, it is essential to have a properly designed and efficiently operated sludge processing stage. The design options for each process will be dependent on the type, size, and location of the wastewater treatment plant, and the solid disposal options available. The design must be able to handle the amount of sludge produced and converted economically to a product that is environmentally acceptable for disposal.

As with water processing, sludge process methods will be determined by the specific constraints and requirements of the individual wastewater treatment plant. Our schematic covers the general processing steps found in a typical plant. There will be many plant-to-plant variations that are not illustrated in our guide.  The typical sludge processing steps include: Sludge Thickening, Sludge Conditioning, Dewatering, and Disposal.