Sensory Overload! Solving One Customer Complaint Only to Create Another


  • Shawn Flood - Hazen and Sawyer

Charleston Water System’s Daniel Island WWTP is located near an established neighborhood. While most of the plant has been decommissioned over the years, primary screening, equalization and a conveyance tunnel shaft remain in operation at the site. In response to odor complaints, CWS has implemented numerous odor control measures over the years, some with better results than others. With the equalization and screening structure already served by an existing carbon scrubber system, it was time to check the last box by scrubbing the onsite conveyance tunnel shaft.

Hazen was contracted by CWS to provide design and construction services on the tunnel shaft odor control system. CWS had already completed odor sampling at the shaft which showed high levels of H2S emanating from the shaft. With a contractor onboard and a manufacturer selected, construction began in July of 2014 with an anticipated startup and contract completion in November of the same year.

Immediately following the initial startup of the system, CWS began receiving noise complaints from a nearby resident who said the system was causing an audible “hum” that could be heard throughout her home. Although the system was technically meeting the town’s ordinance on industrial decibel levels at the property line, as the noise complaints mounted and the upset homeowner made daily calls to CWS’s customer service center, the odor control system was shut down to investigate alternative sound abatement options.

After the addition of an acoustical enclosure to house the system blower failed to mitigate the noise to a level acceptable to the customer, an acoustical subconsultant was enlisted to assist. Their report has provided additional abatement options including an inline duct silencer, acoustical wrap on the system piping and vessels and an acoustical wall that would be 15 feet in height.

CWS is currently working towards implementing some of the abatement measures as recommended by the acoustical sub consultant. This presentation will provide an overview and update of the overall project and will also present results from the sound attenuation endeavors and reactions from the affected customers.

For more information, please contact the author at

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