The Village of Essex Junction’s waste water treatment plant features two-1 million gallon holding tanks to store anaerobically digested secondary sludge from their digesters. From 1998-2013, the economics sided with on-site dewatering to deal with the biosolids build-up in the facilty as opposed to hauling off-site. However, finding a reliable dewatering contractor proved challenging. They struggled with contractors polluting the plant with solids they were supposed to be removing, couldn’t deliver dry cake solids, couldn’t arrive on-site in a timely manner, and others who couldn’t operate in all weather conditions.
The P&H solution
In November, 2004, P&H was awarded a bid to dewater approximately 500,000 gallons of 5-5.5% solids. The results were stunning. Despite working through cold, performance-inhibiting temperatures of December in Vermont, we were able to process 470,000 gallons of 5.5-6% sludge to 24-26% cake solids. The costs savings in disposal as a result of the dryer cake solids savings meant that the Village was able to spend more money on dewatering. Choosing to soul source P&H after this successful dewatering project, the Village was able to fully empty their sludge holding tanks for the first time in decades.
We did this, in part, by suggesting that the dewatering be moved into the spring-summer months to maximize the dryness coming out of the centrifuge. This yielded an increase in of the average cake solids up into the 27% vicinity. We began using our Maximus dewatering system at a lower than maximum output. With these performance enhancements, the Village level-funded their solids handling budget, lowered their disposal costs, leaped far ahead of their biosolids accumulations.
The hands-on, custom-tailored approach to dewatering solutions made P&H the logical choice for the Village’s digester cleanout work as well. In 2008, they had us clean out both their primary and secondary digesters. Despite not being cleaned in over 20 years and being overloaded with inorganics and grease, P&H cleaned two-500,000 gallon digesters, scalped all of the inorganics and grease out, transferred the sludge to the Village’s holding tanks, and processed digester contents and the Village’s usual waste stream into the holding tanks. The whole process went so well that the Village had P&H do the next round of digester cleaning in 2013 as part of their waste water plant upgrade.