Charles River Pollution Control District
Project: Rebuild of (4) 90’ Secondary Clarifiers
Charles River Pollution Control District operates a waste water treatment facility serving the towns of Franklin, Medway, Bellingham and Millis, Massachusetts. Its discharges into the Charles River ultimately flow into Boston Harbor and are regulated by a National Pollution Discharge Elimination System (NPDES) Permit.
The customer initially contacted IWWS to perform a relatively simple fix on a clarifier mechanism. Upon further inspection it was found that through many years of use, the RAS seals had worn into the main columns and effectively cut the columns of Charles River’s four secondary clarifiers. The main mechanical mechanisms were also badly worn after 30 years of use and needed to be rebuilt as well and the protective paint coating had worn away from the majority of the steel exposing it to damaging wastewater. Given the state of disrepair of the units, replacement seemed like the only option, even though the newer units being purchased by other waste water treatment facilities weren’t as robust as what Charles River currently had.
IWWS developed a plan for rehabilitating the existing clarifiers for less than the cost of buying new units. Based on their expertise, IWWS projected that the repairs would add at least another 20 years of productive life to each unit. To rehabilitate the units, IWWS completely disassembled each of them. The mechanical drives were rebuilt and the steel structures were removed, blasted and repainted. The RAS seals were modified so that they would not wear into the columns like they had previously. All repairs were done in a timely manner and brought the units back to good working condition.