Among precasters, High Concrete Group has taken the lead with a water reclamation program that is slashing water consumption and boosting process efficiencies. Engineers implemented the nearly $750,000 system so water can be reused in the Denver, Pa.-based concrete batch operation.
High’s system employs vacuum filtration, a significant advance over standard settling basin technology, that conserves approximately 10,000 gallons of water per day that otherwise would be lost to evaporation. In the new process, all wash water from transport mechanisms, batching process mixers, trucks and buckets is captured. Coarse and fine aggregates are settled out, and cement and other particles are separated and trapped
for disposal. The vacuum filtration system also conserves valuable space, allowing it to meet site constraints.
“The initial challenge was to get the processed water in balance and then to appropriately feed the system to keep it in balance,” says Kevin Iddings, vice president of operations for High. “With this portion of the process stabilized, we’re continuing to evolve practices to manage demand with a goal of increasing output without an associated increase in water consumption." The system also has the capability of segregating excess concrete aggregates for reuse according to concrete mix design.
The core of the vacuum system is a horizontal drum with a cloth medium coated with a filter cake of diatomaceous earth. As wash water is pulled through the rotating drum, a knife peels off deposits trapped in the earth. High Concrete Group developed a system of tanks and weirs (spillover devices) to control the water through various stages of treatment and minimize risk of contaminants escaping into the environment.