Spokane County Regional Water Reclamation Facility, operated by Jacobs, processes 8 million gallons per day (mgd) of wastewater collected from both incorporated and unincorporated areas around the Spokane Valley.
IER proposed ALKA-Mag+ (60% Mg(OH)2) as the alternative to caustic soda for cost, safety, and performance benefits.
• IER proposed ALKA-Mag+ (60% Mg(OH)2) as the alternative.
• After seeing usage reduction in bench top experiments, Jacobs was interested in performing an on-line trial of ALKA-Mag+.
• IER provided and installed the equipment needed for a 90 day trial. This included two 1000 gallon poly tanks with agitators and a metering pump with associated feed lines and valves.
Replacement of caustic soda (NaOH) with magnesium hydroxide (Mg(OH)2) for cost, safety, and performance benefits. Spokane County Regional Water Reclamation Facility, operated by Jacobs, processes 8 million gallons per day (mgd) of wastewater collected from both incorporated and unincorporated areas around the Spokane Valley. This facility has a National Pollutant Discharge Elimination System (NPDES) permit to discharge to the Spokane River.
Wastewater is treated with a state-of-the-art Membrane Bioreactor (MBR).
The conversion from caustic to ALKA-Mag+ resulted in a 68% reduction in chemical usage (by volume).
The coagulation properties of ALKA-Mag+ provided a reduction in sludge volume, which resulted in a reduction of sludge hauling costs.
The results of this 90-day trial gave Jacobs moderate cost savings, and the operators did not have any significant issues with the reliability of the feed system.
Magnesium hydroxide provides two hydroxides for alkalinity compared to only one for caustic soda. Replacing approximately 1400 gpd of caustic soda with only 450 gpd of AMALGAM, allowed a 68% reduction in chemical usage (by volume).
During the trial, it was also observed that the centrifuge cake solids had increased by a few percentage points, resulting in a reduction in sludge volume.
In April 2019 nearly 200 tons of sludge were hauled using 25% caustic soda, hereas only 100 tons was hauled in April 2020 using AMALGAM.
This reduction of sludge was again duplicated in May 2020, and has reduced sludge hauling costs.
In addition to the chemicial usage reduction, any resulting improvement in dewatering would become another benefit of the change.
ALKA-Mag+ is a safe, earth-friendly and cost effective alternative to caustic soda, with coagulation properties that allow a reduction in sludge volume and consequently in sludge hauling fees.
Although Jacobs is still evaluating other options, IER was able to offer significant cost savings, as a result of both chemical usage and sludge reduction.
IER takes pride in providing high-quality products, dedicated delivery specialists and equipment, technical credibility in the applications of water and wastewater treatment, and proactive on-site technical service.
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