ALKA-Mag+, an innovative magnesium hydroxide slurry, was used by a dairy in the Pacific Northwest to provide better pH and alkalinity control compared with caustic soda, while also reducing sodium in the discharge, for better environmental and compliance outcomes.
The wastewater discharged by dairy processors is highly saline, indicating high sodium content. Salty effluent can be diluted with other wastewater streams upon discharge, but the high salinity can trigger penalties imposed by local water authorities.
ALKA-Mag+, an innovative magnesium hydroxide (Mg(OH)2) slurry, was found to provide better pH and alkalinity control compared with caustic soda (NaOH), while also reducing sodium in the discharge, for better environmental and compliance outcomes..Download the PDF now
A Pacific Northwest dairy processing facility was generating highly saline wastewater, a potential source of environmental pollution if left untreated.
Throughout the dairy industry, there is a constant requirement to monitor and control wastewater and effluent before discharge from the plant for compliance. Treating dairy wastewater before it is released into water bodies is a complex process, with biological treatments preferred.
The wastewater discharged by dairy processors is highly saline, meaning the sodium content is usually quite high. Too much salt can cause toxicity called “osmotion”. This causes plant tissues to dry out, and can impair their ability to uptake adequate moisture. Salty effluent can be diluted with other wastewater streams upon discharge, but the high salinity can trigger penalties imposed by local water authorities.
Safety: Nonhazardous for employees to handle, and any spill is not reportable.
Environment: Magnesium is a macronutrient and the core element of chlorophyll, while sodium is a salinity hazard.
Buffering: Magnesium hydroxide is the strongest alkaline buffer known, helping to hold pH within a tight range despite acidic pH fluctuations entering the wastewater treatment process. It also prevents pH spikes due to overdosing of chemicals, improving stability and optimizing microorganism activity.
Cost: While ALKA-Mag+ is typically more expensive than 50% sodium hydroxide on a price-per-unit basis, it is significantly less expensive in use. This is because every 1.0 lb of 50% NaOH can be replaced by 0.6 lbs of 60% Mg(OH)2 to provide the same number of moles of hydroxide (OH-) for pH neutralization.
After being asked by the local municipality to neutralize and control the pH swings coming from its wastewater, the dairy plant installed an equalization basin. However, even after installing the new system, the operators still struggled to keep the pH under the compliance requirements, due to exceptionally challenging and fluctuating acidic conditions.
After consulting with the municipality, it was decided that an alkaline reagent would be needed to help control the acid spikes that resulted in the problematic low pH. Because the local municipality applies a portion of its final effluent to the land, the dairy plant was also required to limit the sodium load in its discharge, which restricted the use of caustic soda.
To meet this commitment, the plant operators followed the municipality’s recommendation and chose magnesium hydroxide (ALKA-Mag+) as the ideal alkaline reagent.
Owned by Calix, IER manufactures and distributes magnesium hydroxide products as well as other innovative, environmentally friendly process water and wastewater treatment chemicals and equipment.
The municipality recommended ALKA-Mag+ for its ability to decrease sodium levels in the discharge and for its safety and handling benefits when compared to other solutions.Read the product data sheet
ALKA-Mag+ (60% Mg(OH)2) has a higher neutralizing value per pound than any other alkaline additive. This translates into a 40% reduction in chemical usage when compared with caustic soda. It is also significantly safer for operators to handle and more nutritive for the microorganisms being maintained, making it the most cost-effective option.
ALKA-Mag+ was found to provide better pH and alkalinity control compared to NaOH (caustic soda), while also reducing sodium in the discharge, for better environmental and compliance outcomes.
IER takes pride in being a technically credible wastewater treatment company, not simply a magnesium hydroxide supplier.
For over 20 years, IER has worked with plant engineers and operators to offer the most cost-effective solutions for their specific needs.
This results-driven approach lets IER work with plant engineers and operators to offer the most cost-effective solution, and an optimised dosing rate, for each specific application.
While ALKA-Mag+ is typically more expensive than 50% NaOH on a price-per-unit basis, it is significantly less expensive in use because every 1.0 lb of 50% NaOH can be replaced by 0.6 lbs of 60% Mg(OH)2 to provide the same number of moles of hydroxide (OH-) for pH neutralization.
Magnesium hydroxide slurry is more attractive to end users because of its safe handling properties and buffering ability, which provides the added benefit of excellent pH control.
ALKA-Mag+ magnesium hydroxide buffers to a maximum pH of 9 in most wastewater streams, making biomass-damaging pH excursions less likely. (Lime and caustic soda can easily reach a pH of 12 and 14, respectively).
This contributes to the system’s stability and optimizes microorganism activity, as microorganisms don’t respond well to pH swings.
When choosing an alkali for dairy wastewater treatment, there are many factors to consider:
The plant managers were pleased to see the cost savings achieved by switching to ALKA-Mag+ magnesium hydroxide, an alkalinity supplement for biological wastewater treatment.
ALKA-Mag+ eliminated the environmental issues associated with sodium levels in the discharge, which allowed the municipality to rehabilitate the fields upon which the discharged water was sprayed into healthy farm lands. It also allowed the dairy processor to efficiently prevent pH spikes in its wastewater discharge, and achieve time and cost savings with a safe, easy-to handle and environmentally friendly solution.
EFFECTIVE pH CONTROL & LONG-LASTING ALKALINITY
With magnesium hydroxide slurry, a nutrient in the form of magnesium is readily available to microorganisms.
Magnesium hydroxide provides more alkalinity on an equal weight basis when compared to hydrated lime and caustic soda, which lowers chemical consumption.
By replacing the sodium in caustic soda or soda ash with the magnesium ion, the treated wastewater is transformed from having to deal with a detrimental form of salinity (Na+) to the benefit of a macronutrient (Mg+2). Mg+2 is the core element in chlorophyll that drives photosynthesis in plant leaves… you can’t get greener than that!
EASE OF USE & SAFE HANDLING
Unlike caustic soda, magnesium hydroxide is non-hazardous and non-corrosive when used properly, which makes handling safer and easier.
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