Scottish Water undertook a major infrastructure project in Cowdenbeath, which included building two new Combined Sewer Overflows (CSOs) to manage increased surface water from the town. Previously, wastewater from Cowdenbeath was treated at a Waste Water Treatment Works (WWTW) on the town's southeast edge, discharging into Lochgelly Burn. As the town grew, this WWTW was converted into a pumping station redirecting flows to a larger facility in Glenrothes, with a 1200m³ holding tank retained for this purpose. However, the additional flows from the new CSOs, totaling 229,700 m³ annually, exceeded the capacity of the pumping station and holding tank. Thus, a new treatment facility was needed on site to manage and treat intermittent CSO flows before discharge into Lochgelly Burn. Scottish Water aimed to avoid building a full-scale WWTW and sought a low-maintenance treatment solution capable of handling variable flows and meeting discharge regulations into the burn.

The chosen site for the treatment facility was east of the pumping station, located on an old landfill covering mine workings. This required significant ground remediation costs, emphasizing the need to minimize the treatment system's size. Therefore, an aerated vertical flow reed bed was selected for its high treatment capacity per unit area. The design included a deeper bed than usual to further reduce the required treatment area. Based on nine years of modelled CSO flow and load data, it was determined that achieving complete treatment for all flow conditions would not be cost-effective. Instead, the design focused on achieving 79% of the annual BOD load, ensuring 95% overall compliance, and treating 100% of the ammonia load. The reed bed system, with a 2-meter deep bed covering 4,000 m², could handle up to 4,000 m³ per day, with flows fed from a 3,000 m³ holding tank at a maximum rate of 46 liters per second. Excess flows beyond storage capacity would occasionally discharge into Lochgelly Burn, diluted by the assumption that such events would be rare and infrequent.

The aerated reed bed system provided Scottish Water with an effective, low-maintenance treatment solution in Cowdenbeath, eliminating the need for a new WWTW to manage increased wastewater flows from the new CSOs. Compared to other options, the system offered lower total expenditure (TOTEX) and enhanced the landfill site aesthetically and ecologically.