About the ADS Water Quality Unit & Infiltration System
General Information Performance Data Water Quality Treatment Process Design




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System Performance

Water Quality Treatment
The ADS Water Quality Unit & Infiltration System does an exceptional job of removing nearly all of the pollutants commonly associated with stormwater performance assessment. It consistently exceeds EPA’s recommended level of removal for total suspended solids, and meets regional ambient water quality criteria for total phosphorus, heavy metals, and petroleum hydrocarbons. However, it did not demonstrate an ability to treat nitrogen. This is typical in non-vegetated aerobic systems. Like all other systems monitored at UNHSC, it does not provide chloride removal, but does exhibit an ability to dampen chloride peaks.

The chart at top right reflects the system’s performance in removing total suspended solids, total petroleum hydrocarbons, dissolved inorganic nitrogen, total phosphorus, and zinc. Values represent results recorded over a two-year monitoring period, with the data further divided into summer and winter components.

Water Quantity Control
Like other infiltration and filtration systems, the ADS system exhibits a tremendous capacity to reduce peak flows and could be used to reduce runoff volume in appropriate soils, such as those belonging to groups A or B. In the figure at bottom right, it demonstrates effective peak flow reduction and lag times in all seasons.

Maintenance
The maintenance requirements of the ADS Water Quality Unit & Infiltration System includes periodic inspection for, and removal of, trash and floating contaminants in the WQU, and the periodic removal of solids by a vacuum truck from both units. The WQU has two manholes for easy access and clean out. Proper maintenance of the accessible WQU prevents costly maintenance of the larger IU. System maintenance was not needed during its evaluation at the field site.

Cold Climate
This system’s water quality treatment and volume control capacity remained strong in all seasons, reinforcing the conclusion that filtration and infiltration systems perform well, even in cold climates.