Atkinson, Nebraska; ISAM™ - Integrated Surge Anoxic Mix

Client: Atkinson, Nebraska

Solution: ISAM™ - Integrated Surge Anoxic Mix

Background:

The City of Atkinson, Nebraska could not meet the Nebraska Department of Environmental Quality (NDEQ) effluent discharge requirements based on the new ammonia regulations. The existing plant also required extensive service and maintenance to keep the outdated equipment operational. Left with no choice, the plant needed to be upgraded.

The City evaluated several different activated sludge processes for their upgrade and determined the Fluidyne ISAM™ - Integrated Surge Anoxic Mix system as the best solution based on overall capital cost, performance and maintenance.

Fluidyne’s ISAM™ is a revolutionary upgrade in wastewater treatment technology. The ISAM™ includes three different compartments all working together to provide BOD, TSS and nitrogen removal along with sludge reduction. The first compartment is an covered anaerobic tank that removes floatable and settleable solids. The second chamber is a combination anoxic basin/flow equalization basin to buffer peak flows and loads as well as provide an anoxic step for denitrification if required. The third compartment is a sequencing batch reactor (SBR). Sludge that is generated in the process is bled back to the first compartment where it settles out and is thickened and digested anaerobically.

The Fluidyne ISAM™ system configuration consists of two (2) ISAM™ tanks (covered and vented, each 18.25’ x 16.5’ x 18’ TWL x 21’), two (2) SAM™ – anoxic/flow equalization tanks each (12’ x 24’ x 18’ TWL x 21’), two (2) SBR tanks each (24’ x 24’ x 18’ TWL x 21’) and two (2) Aerobic Sludge Holding tanks each (18.25’ x 6’ x 18’ TWL x 21’). The new plant was designed for an Average Flow of 0.149 MGD, a Peak Daily Flow of 0.387 MGD, BOD of 249 lbs/day, and TKN of 56 lbs/day. Other plant improvements consist of new screening equipment and new UV disinfection.

The plant was commissioned on July 21, 2014 and has been operating well below the effluent requirements of 25 mg/L BOD, 30 mg/L TSS and 1.56 mg/L NH3-N (ammonia) June through October and 11.9 mg/L November through May. The previous effluent data recorded from the old plant had ammonia levels averaged 7.6mg/L in 2008 and 6.7mg/L in 2007 during June through October. Since start-up the average daily flow has been 0.107 MGD and the plant has treated approximately 27 million gallons of wastewater.

From July 21, 2014 through March 25, 2015 no sludge has been wasted out of the ISAM™ process for final disposal. ISAM™ Tank #1 has approximately 13’ of sludge accumulation with an approximate 8% solids concentration. ISAM™ Tank #2 has approximately 11’ of sludge accumulation with an approximate 4% solids concentration. This clearly demonstrates the sludge reduction feature of the ISAM™ system. The sludge yield of the Fluidyne ISAM™ at Atkinson is about 1/10th of a typical extended aeration plant. The end result with an ISAM™ system is 10 times less sludge at up to 5 times the concentrations.

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