Every wastewater treatment plant reaches a point when existing solutions can no longer keep up with reality. Variable loads, increasing environmental requirements and equipment that has been operating for years eventually lead to the decision to modernize.
This was also the case at Butte-Silver Bow Wastewater Treatment Facility. Two belt filter presses, used for many years, reached the end of their service life and their performance no longer met the facility’s current needs. Increasing loads, the need to reduce operating costs and growing operator involvement made the modernisation of the sludge dewatering system a necessity.
In response to these challenges, ESMIL was selected as the manufacturer and supplier of a new sludge dewatering system based on ESMIL-Tsurumi multi-disc screw presses.
Modernization objectives
The modernization project focused on improving the sludge dewatering process and adapting it to the facility’s current operating conditions. The key objectives included:
- improving system stability and operational efficiency,
- reducing polymer consumption,
- lowering the overall operating costs of the process,
- reducing operator involvement in day-to-day operation,
- ensuring long-term, predictable system performance.
Solutions supplied by ESMIL
As part of the project, ESMIL manufactured and delivered a complete sludge dewatering system, including:
- two MDQ-404 multi-disc screw presses, designed for continuous and stable dewatering of waste activated sludge, each with flow rate of up to 34 m³/h,
- five screw conveyors for sludge cake transport,
- one distributing conveyor equipped with two slide gates, enabling even and controlled distribution of dewatered sludge,
- two polymer preparation and dosing stations, each with capacity of up to 38 l/h,
- three sludge feed pumps, each with capacity of up to 45 m³/h,
Automation and control system
An important part of the supplied solution was the automation and control system, designed for fully automatic operation and to minimise day-to-day manual involvement.
The system includes:
- central control panels responsible for operating: the dewatering presses, sludge cake conveying system, distributing conveyor,
- local control panels enabling independent operation of the sludge feed pumps,
- touchscreen HMI operator panels providing clear access to process parameters,
- an additional local touchscreen panel dedicated to operation of the discharge conveyor.
The dewatering system operates automatically, with operator involvement reduced to the minimum. Key process parameters are available for remote monitoring via the plant’s SCADA system, allowing real-time tracking of performance, alarms and operating trends.
Implementation results
After commissioning the upgraded sludge dewatering system, the facility reported a clear improvement in operating performance. The system maintains a stable waste activated sludge flow rate of up to 34 m³/h per dewatering press, while ensuring consistent and predictable process conditions.
In addition, the plant achieved:
- reduced polymer consumption,
- a more consistent dewatering process,
- lower maintenance requirements compared to the previously used belt presses,
- simpler operation and greater predictability of system performance.
Conclusion
The modernization of the sludge dewatering system at Butte-Silver Bow Wastewater Treatment Facility shows that replacing worn-out belt filter presses with multi-disc screw presses can deliver measurable operational benefits. The technology upgrade stabilised process performance, reduced operating costs and eased the workload for operators in day-to-day operation.
This project reflects ESMIL’s approach, where the key priority is tailoring the solution to the facility’s actual operating conditions and the investment goals of wastewater treatment plants planning to upgrade existing infrastructure.
