In 2014, the City of Nashua, NH, implemented a $5.57 million sludge dewatering equipment replacement and process upgrade at the Nashua Wastewater Treatment Facility.
Nashua Wastewater Treatment Facility
0.13
hp/1,000 FT3 mixing efficiency
80
% energy savings
Solution
Plant staff and consulting engineering firm Wright-Pierce chose EnviroMix’s BioMix Compressed Gas Mixing System as the most beneficial technology for the project. BioMix was installed to mix:
- Four tanks of 2% solids waste activated sludge
- One tank of 4% mechanically thickened primary sludge
The plant’s BioMix system consists of two (2) 7.5 HP rotary screw compressors (one duty and one standby), an automated valve control panel, and five nozzle headers (one per basin). The system replaced five (5) positive displacement aeration blowers, five (5) coarse bubble aeration systems, and six (6) top entry mechanical mixers.
Rendering of Nashua sludge holding tanks
The total estimated power required for BioMix to achieve homogenous mixing in this application is approximately 6 BHP and represents energy savings of more than 80% versus the previously installed diffused aeration and mechanical mixing technologies.
The BioMix system at the Nashua WWTF provides a straightforward, low-maintenance, energy-efficient mixing solution. Additional benefits of the technology include:
- Variable mixing intensity based on operating depth.
- No low-level limitations – ability to mix at any depth.
- Zero wall penetrations, eliminating the risk of leaking.
Nozzle Header Installation
Results
As facilities look to incorporate energy-efficient technology into their operation and maintenance strategies, the savings offered via BioMix for sludge applications prove the technology to be a superior alternative to conventional diffused aeration or mechanical mixing.