Safety in wastewater treatment

Wastewater treatment presents a multitude of hazards, such as exposure to hazardous chemicals or gases.

Safety of common alkalis for wastewater treatment

Safety of common alkalis for wastewater treatment

Wastewater treatment presents a multitude of hazards, such as drowning; confined spaces; and exposure to hazardous chemicals or gases.

↑ Caustic skin burn caused by sodium hydroxide (caustic soda)

Hazardous chemicals can pose a significant risk to health and safety if not managed correctly. Municipal and industrial plant managers have specific duties under

increasingly stringent health and safety regulations to manage risks associated with using, handling and storing hazardous chemicals.

Being a plant manager at a wastewater treatment plant is an enormous responsibility with the need to answer to many high authorities such as the Environmental Protection Agency (EPA) or Occupational Health and Safety Administration (OSHA).

In this article, we have compared three common alkalis for wastewater treatment, and explained why IER magnesium hydroxide products are the safest and most-cost-effective options.

  1. Ca(OH)2 -> calcium hydroxide, lime slurry, hydrated lime
  2. NaOH -> sodium hydroxide, caustic soda
  3. Mg(OH)2 -> magnesium hydroxide, milk of magnesia

There are laws in each state or territory that set out the requirements for handling and transporting dangerous goods. Switching to safer chemical products means you are not only protecting the health and safety of your people, but you are also making cost savings for years to come.

AMALGAM-60

Magnesium Hydroxide (Mg(OH)2) is a safe, environmentally-friendly, and cost-effective alternative to the use of Sodium Hydroxide (Caustic Soda, NaOH) for wastewater pH and alkalinity control.  Inland Environmental Resources, Inc. (IER) is the Pacific Northwest manufacturer of this chemistry in a 60% Mg(OH)2 product called AMALGAM-60, with plant locations in Pasco and Centralia.

 

Cost:  Every 1.0 lb of 50% NaOH can be replaced with 0.60 lbs of 60% Mg(OH)2 to provide the same number of moles of hydroxide (OH-).  This 40% reduction in daily usage rate translates into a dramatic cost savings – for something that is “green” and safe!

Safety:  Though Mg(OH)2 is much stronger for supplying OH- buffering, it is dramatically safer for operators to handle and for treating wastewater microorganisms.  Mg(OH)2 dissolves only when it encounters acidity, unlike NaOH which immediately releases OH- to burn operator’s skin and eyes.  This is why the pH can rapidly spike to > 12 if Caustic is overfed, while the overfeed of Mg(OH)2 will safely buffer the pH up to 8 or 9.  This controlled release” trait of Mg(OH)2 is a primary driver for its acceptance as an ideal buffering agent for nitrification and anaerobic digestion processes.

“Green”:  Magnesium is the core element of chlorophyll (what makes plants green), while salinity from Sodium is detrimental, especially for land reuse applications.

Freezing:  50% NaOH freezes at 60oF, so in winter 25% NaOH is commonly used.  60% Mg(OH)2 freezes at 32oF, just like water, greatly minimizing freeze concerns.

Solids Settling:  Mg(OH)2 can provide improved solids settling and sludge compaction benefits that NaOH does not.  When Mg(OH)2 dissolves, the Mg2+ cation can coagulate suspended solids to improve both microorganism activity and solids removal efficiency – often reducing polymer usage.

Trial Equipment:  IER supplies agitated storage tanks (from 100 to 1500 gallons) to allow real-time measurement of cost savings while confirming performance, safety, and feed reliability – allowing a clear understanding about how Mg(OH)2 will improve your overall system before deciding to make a permanent transition.  IER supplies AMALGAM-60 in full tanker or small volume quantities using dedicated, in-house delivery specialists and equipment.

Please call if you would like to learn more about IER’s safe, “green”, and cost-effective Magnesium Hydroxide product for your operation.

pH & Alkalinity – How are they related?

A primer on the relationship between the bicarbonate system & pH

The relationship between pH & alkalinity is intimately connected with the chemistry of the aqueous bicarbonate equilibrium system.  An understanding of this will help us to communicate with & understands our customer’s needs.

CO2 +   H2O     <=>     CO2(aq)    <=>     H2CO3        <=>         H+             +              HCO3

                                                                                                   Carbonic acid        Hydrogen ion              Bicarbonate ion

Where <=>  represents a partial (equilibrium) reaction or dissociation

For H2CO3 dissociation constant, ka  = [H+].[HCO3]/[H2CO3]   is a measure of how much it dissociates as a function of [H+] concentration or pH

[H+]         = concentration of H+

[HCO3]  = concentration of bicarbonate ion (alkalinity)

[H2CO3] = concentration of carbonic acid (incl. dissolved CO2)

 

Taking log of both sides   =>  log10ka = log10[H+] + log10{[HCO3]/[H2CO3]}

Reorganizing               -log10[H+] = -log10ka   + log10{[HCO3]/[H2CO3]

And by definition         pH = constant + log10{alkalinity/(carbonic acid+ dissolved CO2)}

Magnesium hydroxide vs caustic soda / sodium hydroxide demonstration

A safe and cost effective alternative to the use of sodium hydroxide (caustic soda) for wastewater alkalinity and pH adjustment.

Magnesium hydroxide is the least expensive and most powerful alkaline chemical treatment available on the market for pH control applications. At the same time, it is by far the safest and most gentle to use. 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 (Mg2+). Mg2+ is the core element in chlorophyll that drives photosynthesis.

Controlling the pH of industrial wastewater is important to prevent harm to the wastewater collection/transmittance infrastructure by minimising the corrosive effect of gaseous acidic contaminants (such as H₂S) or, if applied to farm land, to prevent harm to the irrigated crops. Once the wastewater enters a treatment plant, the control pf pH is essential to optimise aerobic and anaerobic microorganism activity. In this article, we explain how magnesium hydroxide can cost-effectively replace caustic soda and lime in different wastewater treatment applications.

Webinar – Mine and mineral processing water neutralisation and metal precipitation using MHL

Now that you are thoroughly sick and tired of online meetings, an invitation to another webinar is the last thing on your mind.

But imagine if that one webinar saved you thousands in chemical costs or helped avoid a nastic caustic burn at your site?

IER has created just that, an alternative to Caustic soda and lime that can cut your chemical costs and is safe enough to swim in (floaties recommended).

AMALGAM is an Ultra High Surface Area Magnesium based product that can replace regular alkali in most processes where acid neutralisation or heavy metal precipitation is required.

Magnesium hydroxide as a substitute for caustic soda and lime

Magnesium hydroxide is the least expensive and most powerful alkaline chemical treatment available on the market for pH control applications. At the same time, it is by far the safest and most gentle to use. 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 (Mg2+). Mg2+ is the core element in chlorophyll that drives photosynthesis.

Controlling the pH of industrial wastewater is important to prevent harm to the wastewater collection/transmittance infrastructure by minimizing the corrosive effect of gaseous acidic contaminants (such as H2S) or, if applied to farm land, to prevent harm to the irrigated crops. Once the wastewater enters a treatment plant, the control pf pH is essential to optimize aerobic and anaerobic microorganism activity. In this article, we explore three ways magnesium hydroxide has cost-effectively replaced caustic soda and lime in different wastewater treatment applications.

Magnesium Hydroxide boosts energy from a cogeneration anaerobic digester

 

 

Biogas production can be tricky. Biological system efficiency can be upset easily.

AMALGAM has shown strong improvement in biodigester stability, gas quantity and methane content through stabilized alkalinity and the active surface. Boosting biogas and power generation up to 20%.

Winery Wastewater and Odour Control

Through improved wastewater management and odor control, there are many benefits for using Magnesium Hydroxide within the wastewater systems of the wine industry.

Wineries are a relaxing retreat where people love to holiday and day trip. Enjoying the environment and experience that comes with amazing wine. Wastewater is the last thing that visitors want to think about at that time.

It is this reason that it’s so important to keep the wastewater system out of sight and out of mind. pH and odor control of the wastewater systems are critical parameters to ensure that the wastewater system is operating unnoticed. IER has solutions tailored for the wine industry that eliminates the risk of creating odor which can affect sales and the cellar door experience.

Methods of phosphate removal in wastewater

Today, the biggest challenge facing the humans is sustainability. As a species our population and success has been limited by the natural world around us. This changed in the mid-1800s with an explosion of the world population thanks to high yield agriculture, bringing with it an imbalance in natural systems and cycles.

Understanding the huge challenges of anthropogenic global warming and inherit limitations of non-renewable resources such as oil and gas is the biggest sustainability challenge that humans face today. However the need is urgent and there is scientific consensus which gives us an increasingly accurate understanding of the system limits, and guidance on how to avoid catastrophe.

This exponential population growth is in part due to the phosphorous fertilizer extracted from bird guano, and now mined and extracted from rocks, speeding up one part of the phosphorous cycle that enables consumption. Unfortunately, due to the geological timescales of the phosphorous cycle, this effectively limits the total phosphorous available to us, effectively making it a non-renewable resource.

Today Phosphorous is abundant, and because of this we spew phosphorous into waterways and oceans, treating it with Alum or Ferric Chloride and discharging aluminum phosphate or ferric phosphate with no thought for the consequences, and the inevitable long term shortages due to it’s current abundance.

A newly invented technology, Nano-Active Magnesium Hydroxide hold the key to maintaining the balance within the phosphorous cycle, enabling capture within waste water treatment solids which can be recycled directly back into the food chain.

How industry can turn waste into biogas

Many industries create substantial amounts of organic waste, much of which can be detrimental to the environment as well as difficult to dispose of. In many cases, the waste comes with an unpleasant odour, which can result in complaints from nearby residents and affect working conditions for employees. However, it is possible to turn organic waste into biogas to offset energy costs and even create a new revenue stream for businesses.

Transforming waste into biogas works by treating wastewater streams through an anaerobic process in which bacteria breaks down microorganisms in the wastewater stream. This process — similar to fermentation — creates biogas, which mainly consists of methane and carbon dioxide, and may include small amounts of hydrogen sulfide, giving it a distinctive rotten egg smell.

Biogas needs to be combusted or oxidised with oxygen to convert it into energy, at which point it can be used in generators, for example, to create electricity that can be fed back into the grid.

This process can help reduce the amount of industry waste going into the environment, making businesses more environmentally sustainable. It can also reduce the cost of energy because a business can use biogas to replace energy from the electricity grid (or coal-fired or diesel generators). And, if the process creates more energy than the business can use, that energy can be fed back into the electricity grid, yielding an additional source of income.

Hydrogen sulfide and the importance of pH

Without the right systems in place, organisations can fail to create enough biogas to make a difference. When anaerobic mechanisms take place at low pH levels they release more hydrogen sulfide gas, which is toxic and foul smelling — and can corrode assets.

Systems that create too much hydrogen sulfide will reduce the lifespan of processing equipment as well as produce less biogas. Therefore, it’s essential to maintain the pH within the optimum range by dosing an alkali into the water.

A Queensland-based rendering plant was able to save more than $1.5 million in energy costs by improving its biogas production. The plant processes four million kilograms of animal waste each week, using approximately $130,000 of electricity each month as well as 24,000 tonnes of coal each year. In a bid to reduce its energy usage, the business wanted to improve its biogas yield and turn its wastewater treatment process into an energy source rather than a cost centre.

The plant applied  a concentrated and stabilised suspension of magnesium hydroxide to manage alkalinity and control pH in the anaerobic process. This approach is more effective than hydrated lime and caustic soda, reducing the amount of chemicals that businesses need to apply. The approach is also non-toxic and environmentally friendly, providing up to 30% faster neutralisation of acidic waste streams as well as reducing sludge generation for easier disposal.

Using this approach, the rendering plant dramatically increased the amount of biogas it could convert into energy, saving $1.5 million and increasing the lifespan of its assets. The same approach can also reduce the odour from hydrogen sulfide by as much as 70 per cent, which can reduce industry’s impact on neighbouring businesses and residents.

A solution for the environment

Biogas is a viable alternative to traditional waste management approaches. It’s a clean, renewable energy that’s created from materials that would otherwise be wasted. Biogas production from organic waste can reduce the greenhouse gas emissions of energy by more than 20 times and prevents methane from escaping in an open environment directly into the atmosphere. Creating energy through biogas is considered carbon-neutral, so it’s a genuine solution to excess emissions.

With growing concern about the impact of industry and agriculture on Australia’s greenhouse gas emissions and the environment in general, biogas is swiftly emerging as the most attractive, affordable and logical waste management solution available.