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Your Little Rock Wastewater provides several functions along
with multiple layers of services within each.
Function
The Operations Division is responsible for receiving and treating commercial, industrial, and residential wastewater from customers in the City of Little Rock. Using the various combinations of physical and biological treatment processes to remove the waste components from the wastewater stream, the final product of treated and clarified effluent from both the Adams Field and Fourche Creek Wastewater Treatment Plants is reintroduced into the environment via the Arkansas River. While governed by the National Pollutant Discharge Elimination System (NPDES) standards issued through the State of Arkansas, both facilities consistently excel in water quality meeting these standards on a 99.9% basis.
Fourche Creek WWTP
Fourche Creek WWTP is a secondary treatment facility with a step-feed activated sludge process, rated to treat 16 million gallons per day. While required by the State of Arkansas to reduce pollutant loads by 85%, FCWWTP consistently achieves 90 to 95% removal before discharging the treated effluent to the Arkansas River. Sludge from both wastewater treatment plants, Fourche Creek and Adams Field, are combined and thickened at this facility prior to being introduced to one of four 1.2 million gallon primary anaerobic digestion tanks. Held for approximately 30 days, at a constant 95°F, and completely devoid of any free oxygen, these tanks use naturally occurring bacteria to consume 55% of the organic solids in the thickened sludge to produce water, carbon-dioxide, sulfide, and most importantly methane. The methane gas is collected and piped to the Generator Building where it is used as an alternative fuel source to provide up to 60% of the facility’s power. The remaining organic, as well as some inorganic, material is pumped to on-site storage lagoons and held until summer, when it is mixed and hauled to area farmlands as a soil conditioner, called Biosolids.
Adams Field WWTP
The Adams Field Wastewater Treatment Plant serves approximately 70% of the city of Little Rock and has been in operation since 1961, originally equipped with only primary treatment. Secondary treatment facilities were added in 1972 with a design flow of 36 million gallons per day. In 2005-2006, improvements were made increasing the influent flow capabilities from 72 to 94 MGD. Those improvements included 14 MGD Equalization Basin for wet weather storage, new Bar Screens, de-gritting equipment, sludge pumps, UV Disinfection, and backup power generators.
Adams Field WWTP is a complete-mix activated sludge plant which is required by the State of Arkansas to reduce TSS and BOD pollutant loads by 88% and 80%, respectfully. A combination of physical and biological processes on average achieve in the mid ninety percentile reduction. Influent flow is screened to remove trash and larger particles and de-gritted (removing sand and gravel). Wastewater velocities are slowed through three primary and three secondary clarifiers in order to allow for settling and skimming of solid materials.
Flow to the activated sludge secondary process goes through six rectangular aeration tanks, where a biological microorganism population utilizes the incoming dissolved organic material in the wastewater as food. The biological organisms that settle out in the secondary (final) clarifiers are returned to the activated sludge aeration tanks to maintain a viable microorganism population, while some solids are wasted from the plant process daily via pumping through a five mile, force main to the Fourche Creek Treatment Plant for further processing.
The overflow from the secondary clarifiers then passes to the ultra-violet (UV) disinfection building where it is exposed to a pre-determined dosage to kill the bacteria remaining after treatment. Treated wastewater, meeting or exceeding all State and Federal requirements, is then discharged to the Arkansas River, causing no adverse effect on the river or public health. |
STONE WARD