More than seven times the design flow from infiltration
“In addition to the age of the 500,000 gallons per day facility,” said Mike Marlar, now vice president of Hallf Engineering, “the site also had a major problem with the tremendous amount of infiltration that was getting into their system. During the wet weather season, this was often as much as seven times the design flow, so no wonder they kept failing to meet compliance.”
He said the military base, which includes multiple weapons ranges and top-tier training facilities, wanted to immediately double the capacity of its wastewater treatment plant. The expansion was driven by a sharp increase in the number of incoming recruits.
“After considering all the options, and thoroughly doing our homework, we specified an activated sludge oxidation process from Lakeside Equipment Corporation," he said. "We built two oxidation ditches side-by-side (with covered Magna Rotors) for a total design flow of 1 million gallons per day (MGD). It really says something that three decades on, it is all still working very effectively. It has always met compliance. That’s some record!”
Halff Engineering also undertook a complete rehabilitation of the collection system. This called for introducing a new headworks facility with a diversion box, so that when heavy wet weather flow reached critical levels, it was diverted into a new equalization basin, which was designed to hold 1.5 MGD. When the weather improved, with less severe rainfall, the sewage could then be diverted back up through the head of the plant for treatment.
