Client: NF Kawakami LTD - Koloa Kauai, Hawaii
Solution: ISAM™ - Integrated Surge Anoxic Mix
Wastewater treatment in the United States has come a long way since the days of directly discharging sewage into gutters or privy vaults, but many rural and remote areas are functioning with archaic systems that have always met the needs for their population - for example, a farmhouse septic tank. One such process still common in the US is a solution dating back to the early 1800's, aptly called a cesspool.
Cesspools, according to the EPA, are "shallow system(s) for diposing of waste.. most consist of a concrete cylinder with open bottom of perforated sides," allowing pollutants to seep into the groundwater over time. These systems are sill common in Hawaii. According to the Hawaii DOH, there are approximately 88,000 cesspools in the state, with 14,000 on Kauai. Large-Capacity Cesspools (LCC) are no longer allowed by the EPA for their inability to treat sanitary waste and propensity to spread pollutants into the drinking water supplies, meaning that many wastwewater systems in Hawaii are in need of an upgrade.
NF Kawakami LTD of Koloa, Kauai owned one such cesspool beneath the Koloa Big Save Market. Now, it was the company's responsibility to update their wastewater treatment system, and as quickly as possible. Must they create a holding tank for the cesspool, and pay to ship off the waste later? Would they pay to directly connect to the city of Koloa's sewer system? Or was there a third option? After examination, Kawakami and consulting engineers at GMP International decided to pursue a package plant solution, specifically Fluidyne's ISAM™ Package Plant technology.
Their choice can be attributed to a few factors; ease of installation in limited space, cost efficiency in removing waste and proven reliable performance. Fluidyne packaged ISAM™ Sequencing Batch Reactor (SBR) systems incorporate a constant level anaerobic selector chamber, surge/anoxic/mix (SAM™) tank, and one or more SBR basins. The ISAM™ modules are available in standard sizes for average influent flows from 5,000 GPD to 110,000 GPD, and arrive with all the equipment inside the tank pre-installed to minimimze installation time and expense. With the abiility to be buried or installed above grade, ISAM™ SBR's provided the flexibility NF Kawakami LTD needed. Furthermore, the ISAM™ provided a small footprint with no digesters, secondary clarifiers or RAS piping and pumping.
As for waste removal, the compact design of the ISAM™ has the ability to reduce and thicken sludge automatically within the anaeraboic selectror chamber, which is much more effiecient than creating a holding tank while proving more cost-effective than frequently hauling sludge.
Perhaps most importantly, Fluidyne's ISAM™ technology has proven to be excellent and reliable in function; the typical facility achieves less than 10mg/L BOD and TSS, less than 8 mg/L total nitrate and less than 2 mg/L phospohorus. The system has the ability to handle highly variable flows, are expandable, self aspirating and provide automatic scum skimming prior to effluent discharge. With these benefits and more, NF Kawakami and GMP International knew they woudl be investing in the best solution for their plant. Fluidyne was proud to partner with Design Engineers Peter Melynk and Joe Semeniuk of GMP International as well as the General Contractor, Shioi Construction of Lihue Kauai, HI.
Flash forward to now; the Fluidyne ISAM™ technology at the Big Save plant, according to operator Ryan Saike of HOH Utilities is, "Running well". Designed for 7,000 GPD daily flow and a 21 GPM peak flow, the plant has been running at average capacity. Between July 2019 and June 2020, the average influent BOD was nearly 250 mg/L and average TSS was over 100 mg/L. The average effluent BOD over this period was 3 mg/L and the average TSS over this period was 11 mg/L, both significantly below the permit of 30 mg/L. The company, community and environment all benefit from the ISAM™ solution, as the influent pollutants are now being processed instead of stored in a cesspool, waiting to infiltrate the water and soil.