Distribution System Simulators
Distribution System Simulators (DSSs) help us evaluate and understand what happens within distribution pipelines. The DSS units imitate water flowing through pipes. The DDS pipes are located above ground to provide easy access to the entire pipe network. Scientists can study the physical, chemical, and biological activities that occur within pipelines. (See Table 2)
DSS-1 replicates continuous flow conditions. It has six 75-foot (25-meter) lengths of 6-inch (15-centimeter) diameter ductile iron pipe. These pipes are arranged in “pipe loop” designs. DSS-1 has two 1,500-gallon reservoir tanks. This unique engineering design allows operating any combination and configuration of the six loops, such as individual loops, collectively as a unit, or in various configurations according to EPA’s experimental research needs. Each loop is insulated and fitted with a heat exchanger to maintain constant temperature during operation. The distribution system simulator is interfaced with a Supervisory Control and Data Acquisition (SCADA) system, which is used to continuously monitor, control, and record operating conditions and collect data.
Scientists are using DSS1 to study factors that influence biofilm growth and what can be done to control it. Biofilms form when bacteria adhere to pipe surfaces. The trouble with biofilm is that it is highly resistant to many disinfection methods and techniques.
Biofilm samples are collected on “coupons.” Coupons are metal devices that enable scientists to collect samples from the interior surface of a pipe without disrupting water flow. You might say coupons are harvesting devices. They are removed from the distribution pipe. The biofilm sample is scraped off the coupon. The coupons are put back into the distribution pipe. (See Table 1)
DSS-2 is more than 300 feet long. It is a once-through system composed of 6-inch (15-centimeter) diameter PVC pipe. DSS-2 is being used to evaluate water quality in a dead-end branch of a distribution system.
- Understand what happens in drinking water distribution systems
- Determine what physical, chemical, and biological factors promote biofilm growth in pipes
- Develop and test mechanisms to control biofilm growth in a DSS
- Conduct real-time monitoring, data collection, and archiving of water quality using remote telemetry within water distribution systems. These research results will be used to provide guidance on how to use remote monitoring of water quality to detect changes in water quality within distribution systems.
agallons per minute
bfeet per second
cparts per million
dnephelometric turbidity units