Founded in 1989, the Long Trail Brewing Co. quickly outgrew the capacity of its basement location at a Bridgewater Woolen Mill along the Ottauquechee River in the Green Mountains of Vermont. In 1995, the brewery relocated to a larger facility nearby with a wastewater treatment plant designed to treat high strength wastewater with a BOD5 concentration of approximately 10,000 mg/L.
Continued success resulted in increased production volume and the need for a solution that could handle a significant spike in high strength brewery waste. It also had to be cost-effective and meet the confines of the brewery’s limited footprint. In addition, the Long Trail Brewing Co. wanted to find a way to enhance nitrification and denitrification to protect the environment by providing a higher level of nitrogen removal and overall treatment plant stability.
A Cost-Effective & Sustainable Process
An upgrade to the existing activated sludge system using membrane bioreactors (MBRs) or high rate anaerobic treatment technology was initially considered. The BioMag system, however, was ultimately chosen for its cost effectiveness and ability to substantially increase treatment capacity, without necessitating plant expansion.
Simple to integrate, operate and maintain, the BioMag system uses magnetite to ballast biological floc, enhance treatment capacity and improve performance—without adding capital-intensive new tankage or energy-intensive operating costs. With a specific gravity of 5.2 and a strong affinity for biological solids, magnetite substantially increases the settling rate of biological floc, providing for reliable control over the depth of secondary sludge blankets, as well as increases in mixed liquor suspended solids (MLSS) concentration. Higher MLSS concentration enables the treatment of increased hydraulic flows or surges and loadings, all within existing tankage. This technology can be cost effectively applied to both new and existing treatment plants and greatly reduces footprint and tankage, while improving treatment.
Successful Results
With the BioMag system, the Long Trail Brewing Co. doubled the existing flow and organic loading rate, and more than doubled the clarifier solids loading rate (SLR). It also generated additional savings by enabling the company to process heavy yeast concentrations produced by brewing through the BioMag system instead of transporting off-site for disposal.
Although the average daily effluent discharge has increased steadily since 2006, the monthly average BOD5 and total suspended solids (TSS), in the effluent, have decreased.
As part of a total solution, the installation team also helped facilitate full nitrification/denitrification—including upgrading their existing anoxic zones, adding a post anoxic zone and adding more aeration capacity.
“The BioMag system produced results enabling the brewery to produce a higher volume of product with an increased treatment capacity while not increasing its physical or ecological footprint, “said Brandon Mayes, assistant quality assurance manager with Long Trail Brewing Co.
Results of the new system for the Long Trail Brewing Co. included:
- • Existing flow and organic loading capacity were doubled;
- • Clarifier solids loading rate (SLR) was more than doubled;
- • Water treatment capacity increased from 500 lb per day to 1,300 lb per day BOD5
- • Full nitrification and denitrification were achieved;
- • Footprint of the plant was not increased; and
- • Significant capital savings were achieved compared with alternatives considered.
As a winner of the Vermont Governor’s Award for Environmental Excellence, the Long Trail Brewing Co. ranks eco-friendly and sustainable practices as a high priority. The BioMag system exceeded the company’s expectations as an efficient solution for enhanced capacity and superior nutrient removal, as well as a sustainable process for lower OPEX.
