A new wastewater treatment plant is much more than another infrastructure project. Decisions made during the design stage determine how the plant will perform for years to come. The technologies selected at this stage have a direct impact on both process performance and long-term operating costs.
One of the areas where these decisions are particularly important is sludge handling. During the design of a new wastewater treatment plant in Lolo, Montana (USA), the client required a complete system for dewatering activated sludge with an initial dry solids content of approximately 0.7%.
In addition to achieving the required dewatering performance, the system needed to offer low operating costs and straightforward day-to-day operation. To meet these requirements, ESMIL designed, manufactured and supplied a complete sludge dewatering system based on the ESMIL-Tsurumi MDQ Multi-Disc Screw Press, together with all associated equipment.
Design requirements
The system was designed to dewater activated sludge with a dry solids content of approximately 0.7%. The primary objective was to achieve performance parameters that would ensure both efficient operation and low long-term operating costs.
The design specifications included:
- Capacity: approximately 75 kg DS/h
- Dry solids content of the dewatered sludge: 16-20%
- Filtrate quality: ≥95% solids capture
Each of these parameters has a direct impact on the long-term operation of the installation. A higher dry solids content reduces the volume of sludge requiring transport and disposal, resulting in lower and more predictable operating costs. High filtrate quality minimises suspended solids losses, while appropriately selected capacity ensures reliable operation of the entire system. These requirements formed the basis for selecting the most suitable dewatering technology.
Selected solution – sludge dewatering system based on the ESMIL-Tsurumi MDQ Multi-Disc Screw Press
Based on the project requirements and process analysis, ESMIL engineers developed a complete sludge dewatering system centred on the ESMIL-Tsurumi MDQ-401 CLS Multi-Disc Screw Press. The process line also includes a polymer preparation system and an ESMIL screw conveyor for transporting the dewatered sludge.
All equipment was selected and integrated as a single process system, ensuring seamless interaction between the individual components and reliable operation of the entire installation.
Lower operating costs with MDQ technology (ESMIL-Tsurumi)
The cost of sludge dewatering extends far beyond the initial equipment purchase. The overall efficiency of the investment is largely determined by the operating costs incurred throughout the system’s service life.
ESMIL-Tsurumi MDQ technology helps reduce operating costs through:
- Slow-speed operation, reducing energy consumption
- A self-cleaning filter disc system, minimising wash water consumption
- A robust design that ensures a long service life while reducing maintenance requirements
As a result, the customer benefits from a solution that not only meets the required process performance but also helps minimise the total cost of ownership of the sludge dewatering system.
Conclusion
Following installation, the system underwent commissioning and performance testing, confirming correct operation and achievement of the specified design parameters. After the successful completion of commissioning, the complete sludge dewatering line was handed over for operation.
When designing new wastewater treatment plants, it is essential to consider not only process performance but also long-term operational requirements. The selected dewatering technology should provide reliable operation while ensuring predictable operating costs throughout the lifetime of the installation.
The project in Lolo demonstrates that ESMIL equipment is increasingly being specified at the design stage of new wastewater treatment plants, where long-term operating efficiency is considered just as important as process performance.
