Wastewater overflows into Mattawoman Creek watershed

Heavy rains, pump failures blamed

Approximately 5.8 million gallons of raw wastewater overflowed into the Mattawoman Creek watershed near the Mattawoman Waste Water Treatment Plant on Hawthorne Road (Route 225) throughout the day Monday as a result of heavy rains and the failure of two of the plant’s four pumps.

It took over seven hours for Charles County Department of Public Works staff and contractors at the plant to bring the overflow under control.

According to the Charles County Citizen Notification System, the overflow, which was a mix of stormwater and sewage, was caused by “heavy rains in conjunction with multiple pump failures.”

Heavy rains over the weekend resulted in large amounts of stormwater flowing into the drainage systems that feed into the treatment plant.

Under normal conditions, the plant’s pumps would be able to handle such a surge. However, due to an unusual combination of circumstances only one of the plant’s four pumps was working at the time, Gregory Boykin, assistant director of public works/utilities, told the Maryland Independent.

Boykin said that prior to the storms, one of the pumps had been taken offline for routine maintenance.

However, one of the remaining three pumps experienced a mechanical failure, and approximately 12 hours later another pump failed due to an electrical malfunction.

The sole remaining pump was unable to handle the mix of stormwater and sewage by itself, and eventually the drainage backed up into the main line into the treatment plant, called an interceptor, and began to overflow through several manholes located nearest to the treatment plant.

The overflow was discovered at 10 a.m. Monday. Public works personnel and contractor crews were able to install temporary pumps that enabled them to arrest the overflow by 5:30 p.m. the same day.

As of 11 a.m. Tuesday, the plant was operating at normal capacity again.

Boykin said that the pumps, which were installed in 1979, are each able to handle around 10 million gallons of effluent per day. Under the county’s capital improvement program, they are scheduled to be replaced by six new pumps that will increase the capacity of the treatment plant.

The county has posted notices along Mattawoman Creek advising residents not to fish or swim in the creek until further notice.

The Department of Public Works will be monitoring the water quality in the Mattawoman and will advise people when the contamination levels return to normal.

“It all depends on how much it’s going to rain,” Boykin said.

The current forecast for the rest of the week is for partly cloudy skies.

The overflow shines a spotlight on the need for upgrades to the treatment plant, which are included in the county’s capital improvement budget.

The county will be tendering a request for proposals in July for the construction of a 10-million-gallon storage tank to increase the plant’s holding capacity, which will help alleviate backups in the event of stormwater surges like the one that caused Monday’s overflow.

Money has been added to the county’s budget to allow the department of public works to continue tearing up and replacing old and damaged drainage pipes throughout the county, an ongoing process.

The department is also in the process of reinforcing and bolting down manhole covers along the main interceptor line leading into the treatment plant to allow the line to hold almost twice the pressure of wastewater than before.

Boykin said that the manhole reinforcements cost around $12,000 per cover.

Residents seeking additional information can contact the Utilities Division of the Department of Public Works at 301609-7400.