Addressing odor problems is a pressing concern in the WWT industry. One of those problems that has to be “fixed and fixed NOW!” Sometimes the first answer is installing a carbon, chemical, or biological scrubber. An alternative approach to the same problem is the addition of THIOGUARD®, which will offer superior odor reduction results, while at the same time delivering the most crucial cost saving benefit of all – system-wide corrosion prevention.
Infrastructure Corrosion is undoubtedly the most significant problem facing today’s plant operators and engineers. The EPA puts the funds required for infrastructure repair and replacement at $271 Billion.
So, when you are faced with an odor problem, and you are considering adding a scrubber to your lines, you may want to ask yourself this question – Will adding an expensive scrubber help prevent corrosion and maintain and extend the engineered life of my infrastructure?
Carbon, chemical, or biological scrubbers are not designed to prevent corrosion. Scrubbers, by design, draw air through your lines, potentially pulling more H2S out of solution, and contributing to corrosion – specifically in crown and manhole infrastructure.
THIOGUARD® added to your system, generally through a single feed unit, suppresses H2S system-wide, eliminating your odor problem, in many cases reducing total gases released from the wastewater stream. The benefits to your infrastructure and your plant are immediate and lasting. Through a single application point, you are effectively maintaining and extending the engineered life of your existing infrastructure. Other downstream benefits include a reduction in the production of sludge, and enhanced clarification and dewatering.
Where scrubbers are currently in use, THIOGUARD® , added upstream, will greatly reduce the overall load, thereby reducing operating costs and increasing the lifespan of existing equipment and structures.
THE ADDITION OF THIOGUARD® INCREASES LIQUID & SURFACE pH LEVELS, PREVENTING THE ACIDIC CONDITIONS THAT CAUSE CORROSION.
By reducing the acidity in your system, you’ll reduce corrosion dramatically, in some cases by as much as 100X, when compared to other treatments. THIOGUARD® is typically added through a single Feed Unit, and provides “corrosion-controlling” benefits throughout your system, from collection system source to treatment plant discharge.
Corrosion is an incredibly COSTLY problem facing
America’s Water System Infrastructure.
THIOGUARD® is a proven solution to maintaining & extending the life of our nation’s water Infrastructure while providing multiple benefits downstream.
Use alkalinity profiling in wastewater operations to control
biological activity and optimize process control
The Water Environment Federation’s new Operations Challenge laboratory event will determine alkalinity needs to facilitate nitrification. Operators will evaluate alkalinity and ammonia by analyzing a series of samples similar to those observed in water resource recovery facilities.
This event will give operators an understanding of how alkalinity works in the wastewater treatment process to facilitate nitrification, as well as the analytical expertise to perform the tests onsite. This provides the real-time data needed to perform calculations, since these analyses typically are performed in a laboratory that can present a delay in the data.
What is alkalinity?
The alkalinity of water is a measure of its capacity to neutralize acids. It also refers to the buffering capacity, or the capacity to resist a change in pH. For wastewater operations, alkalinity is measured and reported in terms of equivalent calcium carbonate ( CaCO3). Alkalinity is commonly measured to a certain pH. For wastewater, the measurement is total alkalinity, which is measured to a pH of 4.5 SU. Even though pH and alkalinity are related, there are distinct differences between these two parameters and how they can affect your facility operations.
Alkalinity and pH
Alkalinity is often used as an indicator of biological activity. In wastewater operations, there are three forms of oxygen available to bacteria: dissolved oxygen (O2), nitrate ions (NO3-), and sulfate ions (SO42-). Aerobic metabolisms use dissolved oxygen to convert food to energy. Certain classes of aerobic bacteria, called nitrifiers, use ammonia (NH3) for food instead of carbon-based organic compounds. This type of aerobic metabolism, which uses dissolved oxygen to convert ammonia to nitrate, is referred to as “nitrification.” Nitrifiers are the dominant bacteria when organic food supplies have been consumed.
Further processes include denitrification, or anoxic metabolism, which occurs when bacteria utilize nitrate as the source of oxygen and the bacteria use nitrate as the oxygen source. In an anoxic environment, the nitrate ion is converted to nitrogen gas while the bacteria converts the food to energy. Finally, anaerobic conditions will occur when dissolved oxygen and nitrate are no longer present and the bacteria will obtain oxygen from sulfate. The sulfate is converted to hydrogen sulfide and other sulfur-related compounds.
Alkalinity is lost in an activated sludge process during nitrification. During nitrification, 7.14 mg of alkalinity as CaCO3 is destroyed for every milligram of ammonium ions oxidized. Lack of carbonate alkalinity will stop nitrification. In addition, nitrification is pH-sensitive and rates of nitrification will decline significantly at pH values below 6.8. Therefore, it is important to maintain an adequate alkalinity in the aeration tank to provide pH stability and also to provide inorganic carbon for nitrifiers. At pH values near 5.8 to 6.0, the rates may be 10% to 20% of the rate at pH 7.0. A pH of 7.0 to 7.2 is normally used to maintain reasonable nitrification rates, and for locations with low-alkalinity waters, alkalinity is added at the water resource recovery facility to maintain acceptable pH values. The amount of alkalinity added depends on the initial alkalinity concentration and amount of NH4-N to be oxidized. After complete nitrification, a residual alkalinity of 70 to 80 mg/L as CaCO3 in the aeration tank is desirable. If this alkalinity is not present, then alkalinity should be added to the aeration tank.
How much alkalinity is needed? To nitrify, alkalinity levels should be at least eight times the concentration of ammonia in wastewater. This value may be higher for untreated wastewater with higher-than-usual influent ammonia concentrations. The theoretical reaction shows that approximately 7.14 mg of alkalinity (as CaCO3) is consumed for every milligram of ammonia oxidized. A rule of thumb is an 8-to-1 ratio of alkalinity to ammonia. Inadequate alkalinity could result in incomplete nitrification and depressed pH values in the facility. Plants with the ability to denitrify can add back valuable alkalinity to the process, and those values should be taken into consideration when doing mass balancing. (For Operations Challenge event, the decision has been made to not incorporate the denitrification step in process profiling.) To determine alkalinity requirements for plant operations, it is critical to know the following parameters:
influent ammonia, in mg/L,
influent total alkalinity, in mg/L, and
effluent total alkalinity, in mg/L.
For every mg/L of converted ammonia, alkalinity decreases by 7.14 mg/L. Therefore, to calculate theoretical ammonia removal, multiply the influent (raw) ammonia by 7.14 to determine the minimum amount of alkalinity needed for ammonia removal through nitrification.
257 mg/L is the minimum amount of alkalinity needed to nitrify 36 mg/L of influent ammonia.
Once you have calculated the minimum amount of alkalinity needed to nitrify ammonia in wastewater, compare this value against your measured available influent alkalinity to determine if enough is present for complete ammonia removal, and how much (if any) additional alkalinity is needed to complete nitrification.
For example:
Influent ammonia alkalinity needs for nitrification = 257 mg/L
Actual measured influent alkalinity = 124 mg/L
257 – 124 = 133 mg/L deficiency
In this example, alkalinity is insufficient to completely nitrify influent ammonia, and supplementation through denitrification or chemical addition is required. Remember that this is a minimum — you still need some for acid buffering in downstream processes, such as disinfection.
Bioavailable alkalinity Most experts recommend an alkalinity residual (effluent residual) of 75 to 150 mg/L. As previously identified, total alkalinity is measured to a pH endpoint of 4.5. For typical wastewater treatment applications, operational pH never dips that low. When measuring total alkalinity, the endpoint reflects how much alkalinity would be available at a pH of 4.5. At higher pH values of 7.0 to 7.4 SU, where wastewater operations are typically conducted, not all alkalinity measured to a pH of 4.5 is available for use. This is a critical distinction for the bioavailability of alkalinity. Therefore, in addition to the alkalinity required for nitrification, additional alkalinity must be available to maintain the 7.0 to 7.4 pH. Typically, the amount of residual alkalinity required to maintain pH near neutral is between 70 and 80 mg/L as CaCO3.
Alkalinity provides an optimal environment for microscopic organisms whose primary function is to reduce waste.
In activated sludge, the desirable microorganisms are those that have the capability, under the right conditions, to clump and form a gelatinous floc that is heavy enough to settle. The formed floc or sludge can be then be characterized as having a sludge volume index.
The optimum pH range is between 7.0 and 7.4. Although growth can occur at pH values of 6 to 9, it does so at much reduced rates (see Figures 1 and 2). It is also quite likely that undesirable forms of organisms will form at these ranges and cause bulking problems. The optimal pH for nitrification is 8.0, with nitrification limited below pH 6.0.
Oxygen uptake is optimal at a 7.0 to 7.4 pH. Biochemical oxygen demand removal efficiency also decreases as pH moves outside this optimum range.
Please Note: The information provided in this article is designed to be educational. It is not intended to provide any type of professional advice including without limitation legal, accounting, or engineering. Your use of the information provided here is voluntary and should be based on your own evaluation and analysis of its accuracy, appropriateness for your use, and any potential risks of using the information. The Water Environment Federation (WEF), author and the publisher of this article assume no liability of any kind with respect to the accuracy or completeness of the contents and specifically disclaim any implied warranties of merchantability or fitness of use for a particular purpose. Any references included are provided for informational purposes only and do not constitute endorsement of any sources.
In a recent article in The Georgia Operator titled, “A Multi-Faceted Approach to Odor Control for a 28.5 Mile Long Force Main,”the authors outlined the solutions to a particularly challenging set of problems faced by the Gwinnett County Department of Water Resources.
Among those solutions was the introduction of THIOGUARD® technical grade Magnesium Hydroxide, in place of Bioxide® to address H2S levels at key areas along the force main. The use of THIOGUARD® also allowed the F. Wayne Hill Water Reclamation Facility to discontinue the addition of lime as an alkaline supplement.
The chart below illustrates the dramatic difference in Hydrogen Sulfide (H2S) levels before, and after, the addition of THIOGUARD® technical grade magnesium hydroxide. The addition of THIOGUARD® provided the Gwinnett County Department of Water Resourcescost savings of approximately 40%.
The chemical components of struvite (magnesium, ammonia, phosphorous) exist in every wastewater system. They are specifically found at more highly concentrated levels in biological processes, such as anaerobic digestion… yet struvite scale is not prolific at every plant. This is irrespective of their use of magnesium hydroxide. For several years, Premier has had many customers using THIOGUARD® experiencing no negative impacts from struvite.
Why? Magnesium, an ingredient in THIOGUARD®, is rarely the causative factor for struvite formation. The real explanation is the concentration ratio of the three components mentioned above, COUPLED with mechanical, hydraulic, or chemical inputs facilitating localized aqueous pH spikes, promoting high omega factors, and thus struvite formation (i.e. pump volute or mixer, turbulent elbow, excess caustic or soda ash addition). THIOGUARD®ΩMEGA-S is an easy turnkey patent pending process. The THIOGUARD® ΩMEGA-S program is a small fraction of the cost of other aggressive methods. A few milligrams of Omega-S combined with THIOGUARD® treatment will insure that struvite will not form under any of the many circumstances that can cause the problem.
THIOGUARD® is a safe, industrial-strength milk of magnesia that adds alkalinity and raises pH levels at your treatment plant. In current applications, the addition of Thioguard delivers measurable benefits in three powerful ways:
1. INCREASES ALKALINITY/ELIMINATES CAUSTIC Thioguard increases alkalinity for nitrogen removal. Every gallon of Thioguard dosed results in nearly two gallons of 50% caustic reduced, resulting in significant cost savings and a safer workplace.
2. ENHANCES GREASE CONTROL3. IMPROVES ODOR CONTROL BY 95% WHEN COMPARED
TO CALCIUM NITRATE Thioguard controls odors continuously by maintaining appropriate alkalinity and prevents daily “spiking,” which typically requires additional treatment locations. Nitrates only control odor with increased/residual nitrogen loading to the WRF. In addition, Thioguard is the ONLY commonly used technology that has a direct mechanism to prevent corrosion.
It’s a fact – all Magnesium Hydroxide slurries are not created equal. Why take chances with a Lime or Caustic blend? These lower quality, poorly refined products are being offered – sometimes by questionable suppliers – who are aware of the negative consequences their “blended” product will deliver. Costly negative consequences can include:
UPSET MICROORGANISMS in Biological Processes
POORER QUALITY cake solids, driving up dewatering, disposal and hauling costs
DANGER TO STAFF, creating safety hazards and driving up insurance costs
Adding DETRIMENTAL SCALE and increasing O&M costs
Increased truck traffic due to WEAKER ALKALINE concentration
Thioguard® technical grade magnesium hydroxide, is the only Mg(OH)2 product that can deliver the highest alkalinity as well as safe and consistent pH levels throughout your treatment process. There is no higher grade, or more concentrated form, of Mg(OH)2 slurry than Thioguard. Nothing else comes close in terms of purity, reactivity and stability.
The recent development of these blended chemistries, combining caustic soda or lime with Mg(OH)2 is either an attempt to disguise a lower quality magnesium hydroxide, or a problematic attempt to gain the benefits of magnesia, without the negative consequences of caustic soda and lime. Unfortunately, even the smallest quantities of caustic and lime will negatively affect your entire process, and will likely end up being extremely costly, in the long run. It turns out you do get what you pay for, and when you “cut corners” by introducing lime or caustic soda, your plant is very likely to get burned in the process.
ALL MAGNESIUM HYDROXIDE IS NOT CREATED EQUAL…
AND BLENDED PRODUCTS CANNOT DELIVER THE BENEFITS
OF Mg(OH)2 WITHOUT INTRODUCING MULTIPLE
NEGATIVE CONSEQUENCES.
THIOGUARD Offers:
A Premium Patented Technology – Sourced and Produced in the US
The map shown above (Figure 1) outlines the areas of magnesium deficient soil in the United States. Magnesium deficiency in food and water supplies is becoming a hot topic and has been more widely studied in recent years. Several countries have already begun adding supplemental magnesium to their own water supply.
MAGNESIUM IN PLANT PHYSIOLOGY AND YIELD FORMATION
Magnesium occupies the central position of the chlorophyll molecule, the green pigment which enables plants to utilize solar energy for the production of organic matter (Figure 2).
It is, therefore, not surprising that an adequate Mg supply to plants may act as an activator of important enzymes in phosphorylation, the fundamental process of energy transfer in the plant.
MAGNESIUM IN SOIL
Although the parent materials of some soils may contain very high amounts of magnesium (e.g. basalt, peridotite and dolomite), the total Mg contents of most soils are rather low, namely between 0.05% and 0.5% Mg. Of this amount only a fraction is easily available to the plant, i.e. the magnesium present in the soil solution and the exchangeable Mg absorbed to clay minerals or soil organic matter. High levels of Mg are found in some saline and alkali soils and in soils with a high content of magnesium carbonate. But many of the agricultural soils are low in exchangeable magnesium, particularly those in the humid zones of temperate and tropical climates. High rainfall and soil acidity together with low cation exchange capacity increase the mobility of magnesium and cause heavy losses by leaching. Under these conditions the Mg status of the soils is poor.
In tropical Latin America, for instance, 731 million hectares are deficient in magnesium (or 49% of all soils) mostly classified as Oxisols and Utisols (Ferralsols & Acisols according to the FAO-UNESCO soil map of the world). In Brazil, Mg deficiency symptoms on annual crops have been recorded as frequently as potassium deficiency. In the humid tropics and the wooded savannah of Africa, the soils with low base status which are presently or potentially deficient in Mg cover 44% of the area. In tropical Asia, they amount to 59%.
Usually, soils are considered deficient in plant available magnesium when the content of exchangeable magnesium is below 3-4 mg/100 g of soil. The critical values differ according to the soil texture. They are higher in soils with high content of 2:1 layer clay minerals and high organic matter. An example of Mg soil test rating for the Federal Republic of Germany is given in Table 1.As for other plant nutrients, the status of available magnesium in the soil cannot be considered independently. It is influenced by the contents of other cations, such as calcium (Ca) and potassium (K), and by the soil acidity (pH). The relationship between Mg deficiency of oats and the pH of sandy soils is illustrated in Figure 3.
The occurrence of Mg deficiency symptoms was lowest at about pH 5, indicating an optimum of Mg availability at this pH range. At lower pH, the uptake of Mg is reduced due to the increased concentration of hydrogen (H) and aluminum (al) ions. In very acid tropical soils, mainly formed by sesquioxides of aluminum and iron, the addition of magnesium fertilizers to the soil reduces Al toxicity. At high soil pH, the competition of Ca ions is responsible for the lower Mg uptake. Regardless of the pH, ammonium (NH4) and potassium (K) affect the uptake of magnesium. Thus, heavy dressings of ammonium sulphate or potassium chloride can aggravate Mg deficiency.
MAGNESIUM UPTAKE BY PLANTS IN RELATION TO POTASSIUM (K) UPTAKE
Plants take up magnesium in smaller quantities than potassium, although the contents of exchangeable Mg in the soil and the Mg concentration of the soil solution are often higher than the corresponding values for K. There is antagonism between K and Mg but it seems to be confined to the deficiency range of nutrient availability. Under such conditions, increasing the supply of one nutrient aggravates the deficiency of the other. Usually high contents of Mg can be found in plants deficient in K (plants try to keep the sum of the cations K, Ca, Mg, Na fairly constant). Application of potash fertilizers to correct K deficiency leads to a gradual decrease of magnesium contents in the plant. Provided that the soil is well supplied with available Mg, leaf magnesium will not fall off to dangerously low values but remains above the critical level even at the high K rates needed to exploit the genetic yield potential of the plant (Figure 4).
When both K and Mg are deficient, it is advisable to improve the magnesium status of the soil by adequate Mg fertilizer dressings before applying heavy doses of K.
MAGNESIUM DEFICIENCY AND ITS CORRECTION
Magnesium deficiency symptoms are more and more observed not only on Mg defined soils but also on soils originally well supplied with this nutrient. This is due to higher Mg uptake by high yielding crops under intensive cultivation.
If the requirements are not met by the magnesium supply of the soil or by the application of Mg-containing fertilizers, plants will suffer from Mg deficiency and may show deficiency symptoms at various growth stages.
As magnesium is rather mobile and can be easily transported to the actively growing plant parts, Mg deficiency generally first becomes visible on the older leaves. Although the symptoms differ between plant species, some general characteristics are apparent.
Mg deficiency becomes manifest by pale discoloration of the leaves in part or as a whole (chlorosis) while the veins remain green. At a later stage the color of the affected areas changes to yellowish white; they become translucent and then take a dark color and eventually die (necrosis). In most cases the leaves are brittle and premature defoliation is observed, especially in fruit trees (see Figure 5).
Magnesium plays an essential role in the human and animal metabolism. It is a constituent of many enzymes, the key substances that regulate the life processes in the cells and organs of the body. Too low a Magnesium supply may lead to tetany (e.g. grass tetany, a lethal disease of dairy cattle), brain disturbances, muscular cramp, and eventually heart diseases.
Magnesium deficiency can be avoided if a food source contains sufficient Magnesium. The daily requirement is about 0.3-0.4g of Magnesium for an adult person. The magnesium needs of animals differ greatly. A dairy cow may require 3-6 g of magnesium per day, depending on the level of milk production. However, as the utilization of the magnesium contained in the forage is rather low (in young pasture grass only 10%), the actual quantity needed may become as high as 50 grams of magnesium per day or more. To assure an adequate supply of magnesium to dairy cattle, the forage should contain sufficient magnesium, at least 2 grams of magnesium per kg dry matter. The average Magnesium contents of some food and forage materials are given in Table 2.At Hill Brothers, we are concerned with all things magnesium, so when we run across information like this we want to share it. There are many parallel benefits that magnesium provides to improve human, animal, and plant health, as well as improving biological water treatment.
Sulfide gas is converted to corrosive sulfuric acid on infrastructure surfaces.
The acid dissolves concrete and metal on surfaces inside sewers and wastewater treatment plants, throughout the entire treatment and delivery process. Acidic Corrosion is prevalent in virtually every stage of the process – in your Collection System, your Headworks, in Primary and Secondary Clarifiers, in your Digesters, and in the Disinfection Processes. Corrosion is a system-wide problem, requiring a system-wide solution.
SO, WHY ADD TO THE PROBLEM, RATHER THAN ADDING THE SOLUTION?
Adding or creating ALKALINITY is the most direct and effective way to neutralize the problem of excessive acidity in our water and wastewater infrastructure. However, many common treatments either provide no acid neutralization, or actually consume alkalinity in their chemistry.
Thioguard® provides the greatest power to neutralize acid over long infrastructure distances while providing additional benefits to your WWTP plant’s biological treatment processes. The chart above compares the alkalinity per gallon, among the most commonly used treatment options.
ADDING TO THE LIFESPAN OF YOUR INFRASTRUCTURE –
PREVENTING FURTHER CORROSION:
In an acidic environment (pH=2), corrosion is rampant, tearing through 2″ of concrete in as little as 8 years. When effective surface pH=4, similar corrosion levels are pushed out to 50+ years.
THE ADDITION OF THIOGUARD® BOOSTS LIQUID & SURFACE pH LEVELS, PREVENTING THE ACIDIC CONDITIONS THAT SPEED UP AND ENCOURAGE CORROSION
By reducing the acidity in your system, you’ll reduce corrosion dramatically, in some cases by as much as 100X, when compared to other treatments. Thioguard® is typically added through a single Feed Unit, and provides “corrosion-controlling” benefits throughout your system, from collection system source to treatment plant discharge.
The measured surface pH can then be used to correlate corrosion rate and subsequently, remaining years of useful life of a concrete structure.
The use of Thioguard® by direct addition has been demonstrated to elevate surface pH from a highly corrosive pH=0-2 up to a more desirable range of pH=5-9.
STOP ADDING TO YOUR CORROSION PROBLEMS. START ADDING THE SOLUTION.
Thioguard® is the ONLY commonly used product that has a direct mechanism to PREVENT CORROSION. The benefits of adding Thioguard® to your treatment processes are not limited to the prevention or reduction of corrosion. You will also benefit from a reduction in the formation of sludge – significantly reducing your handling and transportation costs. The benefits are numerous and system-wide, making Thioguard® the Practical Choice for your system.
The chemical components of struvite (magnesium, ammonia, phosphorous) exist in every wastewater system. They are specifically found at more highly concentrated levels in biological processes, such as anaerobic digestion… yet struvite scale is not prolific at every plant. This is irrespective of their use of magnesium hydroxide. For several years, Premier has had many customers using THIOGUARD® experiencing no negative impacts from struvite.
Why? Magnesium, an ingredient in THIOGUARD®, is rarely the causative factor for struvite formation. The real explanation is the concentration ratio of the three components mentioned above, COUPLED with mechanical, hydraulic, or chemical inputs facilitating localized aqueous pH spikes, promoting high omega factors, and thus struvite formation (i.e. pump volute or mixer, turbulent elbow, excess caustic or soda ash addition).
THIOGUARD®ΩMEGA-S is an easy turnkey patent pending process. The THIOGUARD® ΩMEGA-S program is a small fraction of the cost of other aggressive methods. A few milligrams of Omega-S combined with THIOGUARD® treatment will insure that struvite will not form under any of the many circumstances that can cause the problem.
In plants currently using metal salts, the addition of THIOGUARD technical grade magnesium hydroxide can REDUCE OR ELIMINATE METAL SALT DEPENDENCY
Increased regulation of total phosphorus limits are a fact of life, and another challenge for WWT plant operators and engineers. In most treatment plants, metal salts (ferrous/ferric or aluminum) are added for the treatment of phosphates.
THE ADDITION OF THIOGUARD® INCREASES 
THIOGUARD® ΩMEGA-S is an easy turnkey patent pending process. The THIOGUARD® ΩMEGA-S program is a small fraction of the cost of other aggressive methods. A few milligrams of Omega-S combined with THIOGUARD® treatment will insure that struvite will not form under any of the many circumstances that can cause the problem.
3. 
It’s a fact – all Magnesium Hydroxide slurries are not created equal. Why take chances with a Lime or Caustic blend? These lower quality, poorly refined products are being offered – sometimes by questionable suppliers – who are aware of the negative consequences their “blended” product will deliver. Costly negative consequences can include:
As for other plant nutrients, the status of available magnesium in the soil cannot be considered independently. It is influenced by the contents of other cations, such as calcium (Ca) and potassium (K), and by the soil acidity (pH). The relationship between Mg deficiency of oats and the pH of sandy soils is illustrated in Figure 3.
At Hill Brothers, we are concerned with all things magnesium, so when we run across information like this we want to share it. There are many parallel benefits that magnesium provides to improve human, animal, and plant health, as well as improving biological water treatment.
THIOGUARD® ΩMEGA-S is an easy turnkey patent pending process. The THIOGUARD® ΩMEGA-S program is a small fraction of the cost of other aggressive methods. A few milligrams of Omega-S combined with THIOGUARD® treatment will insure that struvite will not form under any of the many circumstances that can cause the problem.
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