Pipe Thrust Restraint in Treatment Plant Applications

There are several types of process flow and pressure needs for pipes that are included within water and wastewater treatment facilities. Some are low pressure applications and only require gravity flow, whereas, others piping systems require substantial thrust restraint. Typically, treatment plants are fairly compact with regard to location of buried structures and pipes and are generally designed with room for future expansion. This may require exposing buried piping systems and may impact thrust capability of pipe systems if they are not designed to accommodate operation during construction. This paper discusses the need for and selection of thrust restraint methods in treatment plant buried and above ground piping systems to accommodate pressure requirements and operation during expansion projects. Examples where this is important include surface water treatment plants and wastewater treatment plants. Particularly where there are significant area restrictions for the treatment plant site. Antelope Valley, East Kern Water Agency's (AVEK) Acton Water treatment plant Near Palmdale California will be reviewed as an example. This facility is located on a very small with a ruggedly terrained site, with only about 5 acres, with a fall of about 60 to 70 feet across the site. Pipes were designed and installed at this facility to accommodate the pipe pressures, tight spaces between hydraulic structures and anticipated expansion from 4 million gallons per day (MGD) initial capacity to 12 MGD. There was not adequate space for use of thrust blocks on the pipes requiring thrust restraint. Therefore, restrained mechanical joints were incorporated into the design. This allows the pipes to be installed in close quarters and does not compromise integrity for future expansion and connections, should digging near the pipe be required.