Berkeley County Water & Sanitation

The Berkeley County Water & Sanitation Authority is responsible for providing approximately 39,000 customers with clean drinking water along with proper disposal of the community’s solid waste and wastewater. Over the years, its 237 employees have earned a well-deserved reputation for service excellence, fiscal responsibility and environmental stewardship.

PROBLEM: One of the areas under the watchful eye of the BCWS is a beautiful lakefront development known as Land O Pines located within the municipality of Moncks Corner. Recently, the BCWS Wastewater Group began noticing that immediately following a major rain event, the volume at the pump station servicing the Land O Pines community would nearly triple. Not only was the additional volume increasing processing costs, but it was also placing an added strain on the equipment required to transport the wastewater downstream towards the treatment facility. The added workload on such items as pumps would eventually result in the requirement for increased maintenance in addition to reducing the anticipated lifespan of the equipment. Tommy Harris, Superintendent of Wastewater Collection for the County, decided that it would be operationally and economically beneficial if the cause of the increases in wastewater flows were located and ultimately eliminated. Since Tommy and his team had already concluded that the huge jumps in volume during major storm events were due to the effects of inflow & infiltration, they now needed to find a cost-efficient method for locating the source of I&I hiding within the 2.1 linear miles of collection infrastructure. The method selected was iTracking® from Eastech.

SOLUTION: On August 28, 2012, working side-by-side with a factory technician from Eastech, five iTracker® I&I Micro Detection Monitors were installed in designated manholes within the 2.1 linear miles of the collection system (see map). Each unit was commissioned in 15 minutes without the requirement for confined space entry. The five iTrackers immediately began monitoring the (5) independent mini-basins within the 2.1 linear mile major basin.

After two weeks of surveillance that included a major 5” cumulative rain event, the five iTrackers revealed the exact volumetric changes between dry and wet weather events within each of the five mini-basins under investigation. It was clearly evident from the recorded data that the 2,200 linear foot mini-basin designated as “129” was responsible for approximately 80% of the suspected Peak RDII. Due to the effects of the 5” rain event on August 28th, 29th and 30th, the average daily flow over the two week surveillance period within mini-basin “129” increased by 7,670 GPD when compared to the average daily dry day flows. Peak period RDII at mini-basin “129” increased flows from 13gpm to 58gpm. As can be seen from the graph Mini-Basin 129, levels increased from an average dry day level of 1.25” to a peak during the storm of 2.65”. This resulted in a volumetric increase in flow of 4.48 times or 45gpm. An analysis of the iTracker at the culmination of manhole “1345”, located just prior to entering the pump station, showed that the peak volume during the August 29th storm increased 2.51 times (37gpm to 93gpm). The iTracker at “1345” confirmed the BCWS Wastewater Group’s initial calculation of an approximate tripling in flow during a major rain event.