The Dyer Wastewater Treatment Plant in Tennessee replaced open-air sludge drying beds with mechanical dewatering using an ESMIL-Tsurumi MDQ Multi-Disc Screw Press. The new system significantly reduces the time required to prepare sludge for transport and further handling while allowing the dewatering process to run continuously, under controlled conditions and independently of the weather.
Thanks to the compact footprint of the MDQ dewatering press, the process also requires significantly less space than the previously used sludge drying beds. During startup, the dry solids content increased from approximately 1% in the feed sludge to approximately 24% in the dewatered sludge cake.
Challenges of sludge drying beds
The Dyer Wastewater Treatment Plant in Tennessee is a small facility that primarily treats municipal wastewater from the city and surrounding area. Until recently, sludge generated at the plant was dried naturally on open-air sludge drying beds.
Although this is a relatively simple method, it comes with several significant limitations. Sludge drying beds require considerable space and the process is highly dependent on weather conditions. Rainfall, temperature and humidity all affect the drying rate, which means the time required to prepare the sludge for further handling can be long and unpredictable.
These limitations led the Dyer Wastewater Treatment Plant to move away from its existing approach and switch to mechanical sludge dewatering, allowing the process to operate continuously and more predictably.
Implementing an MDQ Multi-Disc Screw Press at the Dyer Wastewater Treatment Plant
The Dyer Wastewater Treatment Plant generates waste activated sludge (WAS) with an initial dry solids concentration of approximately 1.0%. Given the relatively small size of the facility, it was important to select a system that would provide the required capacity without requiring extensive infrastructure or a large installation footprint.
After analyzing the process parameters and site conditions, ESMIL specialists designed a system based on an MDQ-202(1) Multi-Disc Screw Press with an inclined screw conveyor for transporting dewatered sludge.
The installed MDQ dewatering press provides a hydraulic capacity of approximately 15 GPM (3.4 m³/h), matching the plant’s current needs. During startup, the ESMIL team verified the performance of the system under actual operating conditions and fine-tuned the process parameters based on the sludge characteristics and site operating conditions.
From 1% to 24% dry solids
During startup, sludge with an initial dry solids concentration of approximately 1.0% was dewatered to approximately 24% dry solids.
This level of dewatering significantly reduces the mass and volume of sludge requiring further handling. The dewatered sludge cake is easier to store, transport and manage, helping reduce costs associated primarily with transportation and disposal.
A compact sludge dewatering system for a small wastewater treatment plant
Implementing mechanical dewatering allowed the Dyer Wastewater Treatment Plant to move away from open-air sludge drying beds and significantly improve the overall process. Instead of relying on a time-consuming drying process dependent on weather conditions, sludge can now be dewatered continuously under controlled conditions and then transferred directly for transport and further handling.
The compact footprint of the MDQ dewatering press was also an important factor. The system requires significantly less space than the previously used drying beds, allowing the plant to switch to mechanical dewatering without dedicating a large area to the new installation.
For small and medium-sized municipal wastewater treatment plants, the Dyer project demonstrates that improving sludge management does not necessarily require a large or complex system. Mechanical dewatering can be a practical upgrade even for smaller facilities, replacing time-consuming natural drying methods with a more efficient and controlled process.
