FACILITIES & PROCESS
Little Rock Water Reclamation Authority operates an Administrative and Maintenance Complex, three water reclamation facilities, 33 pump stations, a peak flow attenuation facility, and 35,897 manholes, all designed to manage your service needs and support our mission of protecting public health and the environment. Together, this infrastructure powers the collection and the multi-step process that cleans used water — removing solids, treating contaminants, and safely returning clean water to the Arkansas River.
FACILITIES
The Adams Field Water Reclamation Facility (AFWRF) has been in operation since 1961 and was Little Rock’s first water reclamation facility. The facility is biologically rated for 36 million gallons per day and hydraulically rated for 94 million gallons per day during peak flow events. From 1961 to 1972, the facility was equipped only with primary treatment. Secondary treatment facilities were added in 1972, and the facility serves approximately 70% of the City of Little Rock. Since 2018, Adams Field has operated as an extended air/step-feed activated sludge facility. The addition of a “Dual Use” filtration system provides tertiary treatment for both average and peak flows. This filtration system includes four filters, with each basin measuring approximately 31 feet long, 10 feet wide, and 14.5 feet deep. The filters are rated for a maximum flow of 58 million gallons per day.
AFWRF is a two-stage “secondary” water reclamation facility, designed to reduce the pollutant load by approximately 90%. A combination of physical and biological processes is utilized to reduce this pollutant load in wastewater. Wastewater from Little Rock enters the facility via three 60-inch-diameter gravity sewer lines, at an average depth of 30 feet below ground, and requires pumping or lifting the sewage for the treatment process to take place.
Treated wastewater, which meets or exceeds all State and Federal requirements, is piped to the Arkansas River through a six-foot diameter pipeline and discharged cleaner than what occurs there naturally.
Arkansas’s most innovative water reclamation facility, Fourche Creek, went online in 1983. It is a secondary treatment plant with a step-feed activated sludge process and an installed biological capacity of 16 million gallons of wastewater per day.
A combination of physical and biological processes is used to reduce the pollutant load by approximately 90% at the facility. Wastewater from southwest Little Rock enters the facility via a pressure line from the Arch Street Pump Station. The biological treatment process comprises three sets of aeration basins and four final clarifiers. Its aeration system has three fine-bubble ceramic diffuser basins with diffused air supplied by four sets of blowers, each capable of supplying 6,350 standard cubic feet of air.
The sludge from the Adams Field, Little Maumelle, and Fourche Creek Water Reclamation Facilities is thickened, digested, and stored at the Fourche Creek facility. Through the digestion process, the sludge is converted into a biosolid material that is applied to properties in the Central Arkansas area as a soil amendment.
The Little Maumelle Water Reclamation Facility (LMWRF) is the newest facility, built in 2011. It is a two-stage secondary treatment process that uses an extended air-sludge configuration. Extended aeration is an aerobic (air-enriched) process in which microorganisms are given a lengthy detention time afforded to oxidize incoming wastewater. Extended aeration treatment is very thorough, with nearly complete oxidation of organic material. This is critical at LMWRF to reduce the amount of solid production, given the limitations and requirements of the solid transfer ultimately to Fourche Creek for further processing and pathogen reduction.
LMWRF began discharging effluent to the Arkansas River on August 8, 2011. The facility’s service area is the 51,465-acre area known as the Little Maumelle Service Basin, of which approximately 15% is within the current city corporate limits. The facility is rated to treat 4 Million Gallons per Day (MGD) of predominantly residential generated wastewater, with a peak hydraulic loading capacity of 14 MGD. Sufficient land is available for future expansion with an ultimate build-out capacity of 12 MGD biologically and 28 MGD hydrologically.
LMWRF incorporates cutting-edge treatment processes and state-of-the-art technologies to minimize odor, noise, artificial light, and vehicle traffic impacts on the surrounding community. Aesthetic design factors have been used to blend with the natural scenic beauty of the surrounding property and nearby Pinnacle State Park. The plant is tied to and controlled by the Supervisory Control and Data Acquisition (SCADA) system, which allows monitoring of the facility from remote locations and from other Little Rock Water Reclamation Authority facilities.
The facility is fortunate to have exceptional effluent quality and state-of-the-art Ultraviolet Radiation disinfection systems. Ultraviolet disinfection of wastewater is a purely physical, chemical-free process where UV radiation directly attacks the vital DNA of bacteria. The bacteria lose their reproductive capability and are destroyed.
This facility is required by the State of Arkansas to reduce Total Suspended Solids (TSS) and Carbonaceous Biological Demand (CBOD) by 85%, and it has weekly and monthly effluent concentration limitations for TSS, CBOD, and Ammonia Nitrogen (NH3-N). This marvel of technology is another classic example of the Little Rock Water Reclamation Authority’s commitment to the future of Little Rock residents and the environment.
The Clearwater Operations/Maintenance Complex sits on a 36.59-acre tract conveniently located at 5300 South Shackleford Road, with easy access to Interstates 30, 430, and 630. The building was constructed in 1989 to replace the LRWRA’s old Central and West End maintenance shops on Arch Street and Asher Avenue.
LRWRA jointly owns the building with Central Arkansas Water. Additionally, the two utilities operate a Fleet Maintenance Department at the Clearwater facility to maintain and repair vehicles and equipment.
The utility’s Collection System Maintenance Department, which consists of about 100 employees, is based at the Clearwater facility, making it the home base for the majority of LRWRA’s workforce.
The Peak Flow Attenuation Facility project is designed to handle a storm where five inches of rain would fall within 48 hours, which is also referred to as a ‘peak flow event.’ The purpose of this facility is to improve the hydraulic capacity of the collection system during heavy rain and address wet-weather sanitary sewer overflows in the western end of the Fourche Bottoms.
The project consisted of constructing a 50 MGD pump station near Mabelvale Pike, 11,500 linear feet of force main, two diversion structures, and a 61 million-gallon concrete storage basin. The detention basins store water generated by rainfall and then discharge into the collection system when flows return to normal. The Arch Street Pump Station rehabilitation and hydraulic upgrade project was also constructed simultaneously with the Peak Flow Attenuation Facility project. These projects complement each other by enhancing the hydraulic conveyance capacity of the sanitary sewer system through the Fourche Creek Bottoms, thereby reducing sanitary sewer overflows during wet weather events.
The 3 basins were completed in late 2018, with an estimate that they will be used only 10 to 15 times annually.
Process
