Primary clarifier performance is often overlooked.  When TSS and BOD removal are adequate in a wastewater treatment system, then what’s the problem with an inefficient primary clarifier?  One of it’s most significant – and costly – impacts is rarely quantified:

The long-term cost of solids accumulation and dredging

At many facilities, especially in the pulp and paper industry, poor primary clarification does not immediately trigger alarms. Effluent limits may still be met. But beneath the surface, a costly problem is building—literally.

A Simple Comparison: 80 mg/L vs 250 mg/L Primary Clarifier Effluent TSS

Consider a 35 MGD paper mill with two operating scenarios:

• Efficient primary clarifier: Averages 80 mg/L TSS
• Inefficient primary clarifier: Averages 250 mg/L TSS

Using standard mass balance calculations:

• At 80 mg/L → ~11.7 dry tons/day into ASB
• At 250 mg/L → ~36.5 dry tons/day into ASB

This results in:

An additional 24.8 dry tons per day entering the downstream system, or 9,000 tons/year that are preventable with a well-operated primary clarifier.

What Happens to These Solids?

They:

• Settle in ASB or Aerated Lagoon
• Reduce available treatment volume
• Contribute “Phantom BOD” when fiber and other organic material degrade slowly over time
• Ultimately requires mechanical removal (dredging)

Quantifying the Impact

Depositing excess solids into an ASB has a cost.  While some anaerobic digestion of organic solids will occur, a considerable fraction of primary solids are inorganic, which will not degrade. Furthermore, anaerobic degradation can be very slow in the biologically active zone where bacteria are primarily focused on soluble BOD.  Eventually, a majority of these solids will need to be mechanically removed via dredging once they are deposited in an ASB.

Over 5 years, the difference between an efficient and inefficient Primary Clarifier could cost the facility 2.26 million dollars in avoidable dredging costs

The Cost of Every mg/L of TSS at 35 MGD

The chart above shows that incremental improvements in primary clarification can lead to large long-term cost savings.

Why is This Cost Often Missed?

Dredging is a lagging indicator.

The system may operate for years before:

• Capacity loss becomes noticeable
• Treatment performance declines
• Emergency dredging is required

By the time action is taken, the cost has already been incurred.

Primary Clarification: The Cheapest Point of Solids Removal

Solids removed in the primary clarifier are:

• Concentrated
• Easier to handle
• Less disruptive to downstream processes

Solids that pass through:

• Dilute into large volumes
• Settle unpredictably
• Require significantly more expensive removal methods

Operational Implications

Improving primary clarification performance is often one of the highest ROI opportunities in a treatment system.

Key focus areas include:

• Sludge blanket control
• Polymer optimization
• Hydraulic distribution
• Equipment maintenance

Even modest improvements can yield substantial savings.

How EBS Can Help

• Primary Clarifier Efficiency Evaluations:
• Depth Surveys: Determine total volume loss, where solids deposition is occurring, as well as providing third-party information regarding the impact of dredging projects.
• Tracer Studies: Determine actual retention time, flow patterns in ASB.

• Evaluation of Long Term Performance Trends: Assess how solids deposition and volume loss is impacting treatment over time.

Conclusion

• Primary clarifier performance is not just an operational metric; it is a financial driver.
• A difference between an efficient primary clarifier and an inefficient one can result in significant avoidable cost over the long term.
• The question is not whether those solids will be removed.
• The question is whether they are removed: now at low cost or later at a much higher cost.

If your facility has not recently evaluated primary clarification performance or solids accumulation trends, this is the opportunity to start.  Fill out our Contact Us form with your facility details, and one of our EBS experts will be in touch! 

Concern or Curiosity?

Part 2 – Thiothrix, Type 021N, and Beggiatoa

In part one of this series, we discussed the differences between activated sludge and aerated stabilization basins (ASBs) with regard to filamentous bacteria and filamentous bulking. We also talked about one of the most common filaments found in ASBs, Haliscomenobacter hydrossis. In this article, we will discuss three other filament species found in aerated stabilization basins – Type 021N, Thiothrix, and Beggiatoa.

These three filaments all share a common metabolic trait – mixotrophy. These organisms can grow on a number of organic compounds heterotrophically, but also may gain energy for growth from the simultaneous oxidation of inorganic, reduced sulfur compounds (e. g. H2S). Thus the presence of reduced sulfur compounds in wastes being treated may give these filamentous organisms a growth advantage over other strictly heterotrophic organisms (i.e. floc formers). It should be noted that actual energy capture from sulfur oxidation has not been vigorously proven, as yet, and that true autotrophy does not occur, as organic carbon compounds are always required for growth.

While we frequently see common or abundant levels of these filaments in aeration basin samples, it rarely makes up a larger portion of the effluent total suspended solids (TSS). It is, however, a useful indicator of system health relative to loading and dissolved oxygen and its appearance can be a useful tool is heading off problems before they become crises.

For more information on filaments in ASBs, contact EBS.

Concern or Curiosity?

Part 1 – Haliscomenobacter hydrossis

Filamentous bulking has long been the bane of activated sludge operations. Biomass or sludge bulking is generally defined as mixed liquor with a sludge volume index (SVI) of >150 ml/g. However, sludge bulking does not definitively translate to an effluent total suspended solids (TSS) problem in the secondary clarifier. Even the slowest settling sludge can be managed if the clarifier is large enough. The problem arises when the settling characteristics of the sludge exceed the capabilities of the clarifier.

This takes us to aerated stabilization basins (ASBs), where TSS concentrations are very low (usually less than 300 mg/l) and settling zone times are measured in days rather than hours. Therefore, the concept of bulking sludge is not usually applicable in ASBs. As long as there is adequate time in the quiescent settling zone, effluent water quality will usually be acceptable. High effluent TSS leaving settling ponds is more often related to dispersed bacteria from BOD overloading or floating solids due to anaerobic activity in the benthic layer of the settling zone.

Certain species of filaments are quite common in aerated stabilization basins in the pulp and paper industry. One of the most common is Haliscomenobacter hydrossis, a small, sheathed filament that is often seen growing outward from floc particles described as “pins in a pincushion.” H. hydrossis can also have a bent shape and there are no septa visible between the cells. In ASBs where floc is often minimal, H. hydrossis can be often found free in the bulk water. Because of its small size, it is often overlooked when only brightfield microscopy is employed.

H. hydrossis is most often associated with insufficient dissolved oxygen levels, which makes it a leading candidate for most common filament in ASBs where low dissolved oxygen is almost the norm in the early part of most aeration basins. When surface aeration is employed, it is not unusual to have large pockets of low dissolved oxygen throughout the basin leading to growth of H. hydrossis.

While we frequently see common or abundant levels of this filament in aeration basin samples, it rarely makes up a larger portion of the effluent total suspended solids. It is, however, a useful indicator of system health relative to loading and dissolved oxygen and its appearance can be a useful tool in heading off problems before they become crises.

For more information on filaments in ASBs, contact EBS.

Pulp and Paper

Within our Pulp and Paper testing suite, AAL offers two test groups unique to the Pulp and Paper industry. Terpenes and Resin Acids are two chemical classes found naturally in trees. Turpentine, which consists of terpenes such as alpha-Pinene and beta-Pinene, can pose significant risks to biomass health and affect wastewater treatment. Resin acids, which are insoluble in water, serve as a protectant and preservative for wood to defend against microbial and fungal pathogens. These characteristics can make Resin Acids highly toxic to WET testing organisms, resulting in WET testing failures. 

Food and Beverage

Long Chain Fatty Acids (LCFAs) and Reduced Sulfur Compounds and Volatile Fatty Acids (VFA) are unique compound classes for those systems that treat wastewater from Food and Beverage processing streams. LCFAs are long–chain organic acids that can disrupt microbiological activity and lead to system inhibition or toxicity by negatively affecting the nutrient exchange between the bulk water and the microorganisms. Reduced Sulfur Compounds are important due to the odor and associated safety risk of these volatile chemicals. Volatile fatty acids (VFAs) are crucial in enchanced biological phosphorus removal (EBPR).

For systems regulated for phosphorus reduction, keeping track of volatile fatty acids (VFAs) enhances the management of the EBPR process, which helps fine-tune the overall functionality of the treatment process. 

Refinery

Several compound classes unique to petrochemical refinery processes are Polyaromatic Hydrocarbons (PAHs), Gasoline Range Organics (GRO), Diesel Range Organics (DRO), and BTEX compounds. These compounds typically form from the refining process. As these compounds enter the wastewater treatment system, treatment can be negatively impacted with high concentrations. For several of these compounds, the EPA has limited the amount that can be discharged to the receiving body of water due to the known carcinogen potential.

Contact us today to learn more about our AAL testing suites and capabilities.

FOR IMMEDIATE RELEASE

Media Contact:
Christina Dietzen
Environmental Business Specialists, LLC
dietzen@ebsbiowizard.com

Environmental Business Specialists, LLC Earns USDA Certified Biobased Product Label

Mandeville, LA. Environmental Business Specialists, LLC announced today that it has earned the U.S. Department of Agriculture (USDA) Certified Biobased Product Label for MicroCarb™.

MicroCarb™ is a glycerin-based carbon source used as a wastewater treatment supplement to support biological systems during low influent carbon conditions, production outages, and nutrient removal programs. It provides a readily available carbon source that is easier and safer to handle than alternative sources. MicroCarb™ contains 100% biobased content, offering facilities and suppliers a renewable alternative to petroleum-derived carbon products while maintaining reliable treatment performance.

The MicroCarb™ can now display a unique USDA label that highlights its percentage of biobased content. Third-party verification for a product’s biobased content is administered through the USDA BioPreferred® Program, which strives to increase the development, purchase, and use of biobased products.

Biobased products empower communities in rural America, create and expand markets, and represent incredible technological advances and innovations.

The USDA Certified Biobased Product Label displays a product’s biobased content, which is the portion of a product that comes from a renewable source, such as plant, animal, marine, or forestry feedstocks. Utilizing renewable biobased materials displaces the need for non-renewable petroleum-based chemicals. Biobased products are cost-comparative, readily available, and perform as well as or better than their conventional counterparts.

“Earning the USDA Certified Biobased Product Label for MicroCarb™ provides our clients with verified transparency in sourcing while continuing to deliver the performance they rely on to stabilize biology and maintain compliance”- Christina Dietzen

“We applaud Environmental Business Specialists, LLC for earning the USDA Certified Biobased Product Label,” said Vernell Thompson, USDA BioPreferred Program. “The label is intended to help spur economic development, create new jobs, and provide new markets for farm commodities. But the label also makes it easier for consumers and federal buyers to locate biobased products and consider planet-friendlier options during purchase decisions. By having their products become USDA Certified Biobased, Environmental Business Specialists, LLC joins an expanding list of businesses combatting inaccurate marketing claims and the practice of greenwashing, while also contributing to a thriving bioeconomy that decreases our reliance on petroleum.”

In the latest Economic Impact Report released by USDA, the biobased products industry supported 4.6 million American jobs; contributed $470 billion to the U.S. economy and generated 2.79 jobs in other sectors of the economy for every biobased job. Biobased products also have a substantial environmental impact, displacing about 9.4 million barrels of oil a year, with the potential to reduce greenhouse gas emissions by an estimated 12.7 million metric tons of CO2 equivalents per year.

About Environmental Business Specialists, LLC

Environmental Business Specialists (EBS) provides wastewater consulting, advanced laboratory diagnostics, operator training, and biological treatment products including industry tailored blends of nutrients, carbon sources, and bioaugmentation. EBS supports industrial wastewater facilities across North America stabilizing biological systems and supporting regulatory compliance.

About the USDA BioPreferred Program

With the goal of increasing the development, purchase, and use of biobased products, USDA’s BioPreferred® Program was first introduced in the 2002 Farm Bill and reauthorized in 2018. It requires federal agencies and contractors to give purchasing preference to biobased products. The USDA BioPreferred Program also includes a voluntary certification and labeling initiative for biobased products. This is referred to as the USDA Certified Biobased Product Label.

More than 1,800 companies across the U.S. and in 47 countries participate in the Program. Have questions? Please contact: Vernell Thompson, USDA BioPreferred Program at Vernell.Thompson@usda.gov

To learn more about the USDA BioPreferred Program click here.

To learn more about MicroCarb™ click here to download the brochure.

In the Kraft paper-making process white liquor, which is NaOH (sodium hydroxide) and Na₂S (sodium sulfide), is used to “cook” wood chips in a piece of equipment known as the digester. In the digester, the wood chips are “cooked” using high temperature and pressure in the presence of white liquor to create wood pulp. One of the byproducts of this process is a liquid that contains wood lignin, excess sodium, sulfur, and other organic materials. The liquid, referred to as black liquor, is sent through a series of evaporation processes to concentrate the solids, which are collected and sent to the recovery boiler where they are burned to produce steam and, eventually, power. Strong black liquor contains about 60% to 65% organic solids that are easily burned for power production.

Black liquor is strongly caustic, releases hydrogen sulfide when interacting with acids, and contains concentrated organic material. For these reasons, black liquor spills into the wastewater treatment plant can throw the system into an upset. These accidental spills by nature are impossible to predict, however, there are multiple resources available to wastewater operators to maintain good treatment in the wastewater treatment plant such as pH adjustment, diversion ponds, and bioaugmentation.

The term bioaugmentation is defined as the application of selected microorganisms to enhance the microbial populations of an operating wastewater system to improve the water quality or lower the operating costs. Bioaugmentation products can provide additional bacteria immediately in response to an increase in loading rather than waiting for the system to both acclimate to the new food source and then grow to accommodate the higher loading. At EBS customer-specific formulations of bacteria, MicroStar and BioStar have been developed by the R&D team to achieve the high rates of degradation in heavily loaded wastewater systems. Also, EBS has patented a bacterial feed system to aid in the enumeration of the dry bioaugmentation product to provide maximum bacterial cells per pound of dry product. This unit, the BAC unit (Bacterial Acceleration Chamber), can grow up to 100X the number of bacteria of the dry product alone. The units are designed to be automatically or manually discharged into an aerated system. Using bioaugmentation via the BAC unit in conjunction with other engineering controls for pH and maximizing aeration will allow a system to respond quicker to a high loading event and have more effective removal early in the system avoiding potential BOD breakthrough to the effluent.

Dealing with blank liquor spills? Contact EBS today for a customized approach to optimizing your treatment system.

Flow cytometry is a laser-based technology that rapidly analyzes a single cell or particle of interest using fluorescent nucleic acid stains. This powerful tool has been used in the medical field for decades to help advance the understanding of immunology, virology, cancer biology, infectious disease monitoring, and more. The use of flow cytometry has been adapted for use in wastewater to quantify live and dead bacterial populations, taking health assessments to the next level. Our clients use this data to assess the current state of their biomass health in the biological treatment system or to monitor the effectiveness of their biocide treatment programs when controlling microbial growth. Our data can become increasingly important after major events, such as chemical spills, facility shutdowns, or startups, which may impact the productivity of biological treatment.

Recently, one of our clients experienced a significant black liquor spill at their facility, resulting in a high Biochemical Oxygen Demand (BOD) in the final effluent. We suspected that the spill caused a substantial reduction in the live bacterial population due to the rapid environmental changes occurring in the treatment basin. Our team arrived on-site the following day to begin assessments. Using flow cytometry, we detected a 41% reduction in the live bacterial population compared to the usual levels at this plant. In response, we implemented a recovery strategy that included adjusting pH levels, enhancing biological activity through bioaugmentation, and adding nutrients. These measures proved effective, and the bacterial levels subsequently returned to normal at a 67% live population.  

The outcome of this intervention was illustrated below using a dot-plot, which compares the counts of live versus dead bacteria before, during, and after the spill occurred. 

The pH of the environment has a profound effect on the rate of microbial growth. pH affects the function of metabolic enzymes. Acidic conditions (low pH) or basic conditions (high pH) alter the structure of the enzyme and stop growth. Most microorganisms do well within a pH range of 6.5 to 8.5. However, some enzyme systems can tolerate extreme pHs and will thrive in acidic or basic environments. Fungi, for example, do well in an acidic environment. Most bacteria and protozoa, however, grow best in neutral (pH 7) environments. Abnormal or irregular pH in biological treatment processes can result in a significant decrease in the rate of removal of organic compounds from the environment, which will affect the effluent biochemical oxygen demand (BOD) concentration.

Many plants must control the pH of their process effluent within an acceptable range before it is mixed with biomass. Even short-term exposure (exposure lasting less than one minute) to extreme pH causes significant microbial destruction. Some influents (process effluents) are slightly on the basic side with pHs between 9.0 and 10.5. Because bacteria generate CO2 (an acidic gas) as a by-product of metabolism, they will self-regulate the pH to some extent, as long as the pH is not so severe as to completely stop the bacteria’s metabolism.

pH approximates the concentration of hydrogen ions in a solution. The pH value is the negative logarithm (base 10) of the concentration of H⁺ ions in the solution. In the laboratory, pH is measured by electrometric pH measurement which is the determination of the activity of the hydrogen ions by potentiometric measurement using a standard hydrogen electrode and a reference electrode.  The pH probe is placed in the sample (while stirring) and the number is recorded once the readings have stabilized. Because it is on a logarithmic scale, it will take ten times as much acid or base (caustic) to raise or lower the pH two units as it did to raise or lower it one unit. For example, if it takes 10 gallons of a particular acid to lower the pH of an influent from 10 to a pH of 9, it will take 100 gallons to lower it from a pH of 10 to a pH of 8.