What Enabled Bridgewater Company to Capture Up to 600 Liters of Oil Per Day
Continuous belt skimming reduced oil loading in effluent systems, improving clarifier performance and lowering treatment burdens
The Problem: Paper mills and manufacturing facilities often struggle with oil contamination in wastewater collection systems. When oil enters primary treatment equipment, it can reduce separation efficiency, increase loading on downstream processes, and create costly and frustrating operational issues.
At Bridgewater, excessive oil entering the mill’s drainage system greatly affected the performance of its Krofta flotation clarifier and placed additional strain on secondary wastewater treatment operations. After unsuccessful attempts to control the problem and a lot of internet research, the facility implemented a Model 4 Oil Grabber Oil Skimmer from Abanaki Corporation. The $6500 installation quickly proved its value by capturing large volumes of oil before it could enter the treatment process, and served as a testament to Bridgewater’s commitment to enhancing the operations of its Effluent Treatment plant.
The result was improved treatment system performance with daily capture rates of up to 600 liters, reduced oil loading, and a projected payback period of just over 12 months.
Excess Oil Reducing Wastewater Treatment Efficiency
Bridgewater’s primary drain pit collected wastewater containing:
- Oil from mill equipment and operations
- Coal dust and grit
- Fibers and fillers from production processes
- Other debris entering the drainage system
Over time, accumulated debris reduced the pit’s holding capacity, preventing oil from naturally separating and floating to the surface. Instead, oil was drawn directly into pumps and carried into the primary Krofta flotation clarifier.
This created serious issues:
- Average oil losses of approximately 200 liters per day per machine entering the drainage system
- Reduced solids removal efficiency in the primary clarifier
- Increased loading on secondary treatment processes
- Oil carryover that encouraged the growth of filamentous bacteria in downstream treatment systems
- Greater risk of poor sludge settling performance and treatment instability
The facility attempted several corrective actions, including leak reduction programs, source collection containers, drain pit cleaning, and temporary oil containment methods. None of these measures proved to be the long-term solution they needed.
The Solution and Measurable Results: Abanaki’s Model 4 Oil Grabber Belt Oil Skimmer Delivers High-Volume Oil Recovery
After evaluating several alternatives, Bridgewater tested an Abanaki Model 4 Oil Grabber Belt Oil skimmer installed in the primary drain pit. The system utilized a 4-inch polymer belt able to continuously attract floating oil from the water surface and discharge recovered oil into a collection system.
The trial unit immediately demonstrated its ability to remove large quantities of oil before contamination could reach the clarifier. Bridgewater installed a permanent system in November of 2004 equipped with additional features to improve operation under high-flow conditions.
Operational improvements and results included:
- Continuous removal of floating oil before it entered the primary treatment process
- Improved performance of the Krofta flotation clarifier
- Reduced loading on secondary wastewater treatment systems
- Lower risk of oil-related biological treatment issues
- Improved solids separation and wastewater treatment stability
- Reduced dependence on temporary oil containment methods
- Captured up to 600 liters of oil per day
- Successfully removed oil that previously bypassed the drain pit and entered treatment equipment
- Improved operating conditions for both primary and secondary wastewater treatment processes
- Projected payback period of just over 12 months based on operational benefits and recovered performance
Oil contamination can significantly reduce the efficiency of wastewater treatment systems with nasty consequences for operational capacity and maintenance. Continuous oil removal at the source of contamination can significantly improve downstream treatment performance—all while delivering a rapid return on investment for industrial wastewater environments like that of Bridgewater.
