Grease, primarily from residential and commercial kitchens, can cause significant operational issues if not managed properly. This post reviews educating the public on the grease problem, emphasizes restaurant grease trap maintenance, outlines collection system pretreatment programs, and explain how bioaugmentation can assist in grease degradation within biological treatment plants.

Understanding the Grease Problem
Grease, fats, and oils are byproducts of cooking and food preparation. When these substances enter the wastewater system, they tend to solidify and create blockages, leading to backups, overflows, and increased maintenance costs. The impact of grease on wastewater treatment plant comes from the fact that insoluble grease/fatty acids take longer to decompose biologically than other soluble organics and nuisance organisms such as M. parvicella and Nocardia forms (foaming) thrive on grease.

Step 1 - Educating the Public (Keep Grease Out)
Public awareness is the first line of defense against grease-related issues. Programs to educate residents and businesses about the proper disposal of grease helps to reduce the amount entering the wastewater system. Simple actions, such as wiping grease from dishes before washing and disposing of it in the trash, can make a substantial difference. Community outreach programs, informative brochures, and social media campaigns are effective tools for spreading this message.

Step 2 - Restaurant Grease Trap Education & Maintenance
Restaurants and other food service establishments are major contributors to grease in the wastewater system. Proper maintenance of grease traps is crucial to prevent grease from entering the sewer lines. I find it interesting that many restaurant workers do not know about the grease trap and how odors blamed on "dumpsters/trash" is actually coming from a poorly maintained trap. Regular cleaning and inspection ensure that they function correctly. Establishments should also train their staff on best practices for grease management and disposal. By adhering to these practices, restaurants can play a significant role in reducing the grease load on wastewater treatment plants. Grease trap microbial products are often subject to debates regarding their ability to reduce FOG entering the collection system. Data collected in studies has demonstrated that well designed grease trap microbial blends when dosed appropriately along with normal inspection/maintenance helps with trap maintenance and lower grease/long chain fatty acids entering the collection system.

Step 3 - Collection System Pretreatment
Pretreatment programs are essential for managing grease before it reaches the wastewater treatment plant. These programs involve installing and maintaining equipment designed to capture and remove grease from the wastewater. Regular inspections and maintenance of the collection system can prevent grease build-up and ensure the smooth operation of the treatment facility. Pretreatment programs also include regulatory measures, such as permits and inspections, to enforce compliance among businesses that discharge grease-laden wastewater. In problem sections of collection systems, you can use added biological cultures to reduce grease accumulation in pipes and lift stations. A side benefit is these grease control programs can also reduce odors and H2S. These cultures must be added upstream of the problem section and allowed to form a beneficial biofilm on pipe walls. In effect, you are transforming the pipe walls and lift station into a biological pretreatment section.

Can Bioaugmentation Aid in Grease Degradation at the Biological Treatment Plant?
Despite best efforts to minimize grease entry into the wastewater system, some grease inevitably makes its way to the treatment plant. Here, bioaugmentation can play a role in enhancing grease degradation. Bioaugmentation involves introducing specific microorganisms into the biological treatment process. These microorganisms accelerate the degradation of fats, oils, and grease, improving the overall performance of the treatment plant.

Nitrification is one of the most complex and crucial processes within the wastewater microbial community. This biochemical process involves the conversion of ammonia (NH₃) into nitrate (NO₃⁻) and is carried out by a specialized group of microorganisms known as nitrifiers. These nitrifiers can be broadly categorized into two main groups: Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB). Both are slow-growing organisms and require specific environmental conditions to thrive, including relatively narrow ranges of pH, alkalinity, and dissolved oxygen levels.

The Process of Nitrification
Nitrification occurs in two main stages:

• Ammonia Oxidation: In the first stage, ammonia is oxidized to nitrite (NO₂⁻) by AOB. This step is represented by the chemical equation (note the following equations not balanced):
• NH₃ + O₂ → NO₂⁻ + H₂O + H⁺
• This reaction is primarily carried out by bacteria from genera such as Nitrosomonas, Nitrosospira, and Nitrosococcus.
• Nitrite Oxidation: In the second stage, nitrite is further oxidized to nitrate by NOB. The chemical equation for this reaction is:
• NO₂⁻ + O₂ → NO₃⁻
• Common genera involved in this process include Nitrobacter, Nitrospira, and Nitrococcus.
  
  

Environmental Conditions for Optimal Nitrification
The efficiency of nitrification is highly dependent on several environmental factors:

• pH
  ​Nitrifiers operate best within a narrow pH range of 6.5 to 8.5. Deviations outside this range can inhibit their activity and slow down the nitrification process. Acidic or highly alkaline conditions can adversely affect enzyme activity and cellular processes in these bacteria.
• Alkalinity
  Alkalinity acts as a buffer to maintain a stable pH in the system. During nitrification, hydrogen ions (H⁺) are produced, which can lower the pH. Adequate alkalinity is necessary to neutralize these acids and maintain a conducive environment for nitrifiers.
• Dissolved Oxygen
  Both AOB and NOB require dissolved oxygen (DO) for their metabolic processes. Optimal DO levels for nitrification typically range from 2 to 4 mg/L. Insufficient oxygen can lead to incomplete nitrification and the accumulation of intermediate compounds such as nitrite.

Challenges in Nitrification 
Inhibition and Activity Reduction
Facilities often report instances where they believe their nitrifiers have been "killed." However, in many cases, it is more likely that the nitrifiers are experiencing inhibition or a decrease in activity rather than a complete die-off. Factors such as the presence of toxic compounds, sudden changes in environmental conditions, or competition with other microorganisms can inhibit nitrification.

Monitoring and Diagnosis
Before implementing widespread changes, importing sludge from another plant, or adding concentrated nitrifier products, it is crucial to accurately diagnose the state of the nitrifier population. Aster Bio’s qPCR technology offers a powerful tool for this purpose. By quantifying the genetic material of nitrifiers, qPCR provides results within hours rather than days, enabling informed decision-making and reducing the need for costly and time-consuming interventions.

Benefits of qPCR Technology

• Accurate & Rapid Results
  Traditional methods for assessing nitrifier populations, such as culture-based techniques, can take several days to yield results. qPCR technology, on the other hand, delivers rapid and accurate data, allowing for timely adjustments to the treatment process.
• Cost and Time Efficiency
  By providing quick insights into the health and abundance of nitrifiers, qPCR helps facilities avoid unnecessary expenses associated with overhauling treatment processes or importing sludge. This technology enables operators to make targeted interventions based on real-time data, saving both time and money.
  
  

We Can Help
Are you struggling with nitrification in your wastewater treatment plant? Don't let uncertainty slow you down at a cost of $225 per sample, qPCR maintains permit and saves money. Contact Aster Bio’s experts today to learn how our qPCR technology can provide you with the rapid and accurate insights you need to optimize your nitrifier populations and enhance the efficiency of your treatment process. Let us help you save time, reduce costs, and achieve better outcomes for your facility. Contact us for more details at [email protected].

​Wastewater treatment plants often face the challenge of foaming, which can disrupt the treatment process and lead to operational issues. Two common filamentous bacteria responsible for foaming are Nocardia Forms and Microthrix parvicella. Understanding their role and implementing control measures is crucial for maintaining efficient wastewater treatment.
 
Nocardia sp & Gordonia (Nocardia Forms)
Nocardia and Gordonia are genera of filamentous bacteria that thrive in wastewater with high concentrations of fats, oils, and grease (FOG). These bacteria form stable foams that can persist for long periods, causing operational problems such as:

• Reduced settling efficiency: The foam can interfere with the settling of solids, leading to poor sludge quality.
• Increased maintenance: Persistent foam can clog equipment and require frequent cleaning.
• Odor issues: The foam can trap odors, leading to nuisance odors.

 
Microthrix Parvicella
Microthrix parvicella is another filamentous bacterium commonly found in wastewater treatment plants. It prefers environments with low oxygen levels and high concentrations of long-chain fatty acids. The presence of Microthrix parvicella , favored during lower temperature months, can lead to:

• Foam formation: Similar to Nocardia, Microthrix parvicella forms stable foams that can disrupt the treatment process.
• Poor sludge settleability: The foam can reduce the efficiency of sludge settling, leading to increased sludge volume and disposal costs.
• Operational challenges: Persistent foam can cause equipment malfunctions and increase maintenance requirements.

 
Control Measures
To mitigate the impact of foaming filaments on wastewater treatment plants, several control measures can be implemented:

1. Optimizing FOG removal: Reducing the concentration of fats, oils, and grease in the influent can limit the growth of Nocardia. This can be achieved through improved pretreatment processes such as grease traps and skimmers.
2. Maintaining proper aeration: Ensuring adequate oxygen levels in the treatment process can inhibit the growth of Microthrix parvicella. Regular monitoring and adjustment of aeration rates are essential.
3. Chemical dosing: The use of chemicals such as chlorine, hydrogen peroxide, or specific biocides can help control the growth of filamentous bacteria. However, this approach should be used with caution to avoid negative impacts on the overall treatment process.
4. Sludge management: Proper sludge handling and disposal practices can prevent the accumulation of filamentous bacteria. Regular sludge wasting and maintaining appropriate sludge age are important factors. Using molecular testing can track problem populations and help operators adjust wasting rates.
5. Foam control agents: The application of foam control agents, such as silicone-based antifoams, can help reduce foam formation and improve operational efficiency.
   
   

By understanding the triggers of filamentous foaming and implementing effective control measures, wastewater treatment plants can maintain efficient operations and minimize the impact of foaming on the treatment process.
​

As temperatures drop microbial growth rates slow and system conditions favor organisms such as the foam producing filament, Microthrix parvicella. With slower growth rates, vital slower growing organisms such as Ammonia Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB) also become more susceptible to washout - hence the common strategy of increasing MCRT during colder months. The challenge is maintaining the MCRT balance needed to protect AOB/NOB (Nitrifiers) while also keeping long MCRT filaments such as M. parvicella and Nocardiaforms below critical levels.

Why you should monitor M. parvicella populations

• Sludge Bulking: It leads to poor settling characteristics, resulting in high sludge volume index (SVI) values.
• Foaming: Creates stable foams that can overflow tanks, causing operational difficulties.
• Process Disruption: Affects the overall performance of the activated sludge process, leading to compliance issues.

Current control strategies

• FOG Control: Keeping FOG down disfavors the foam producing filaments, especially important in winter.
• Adjust MCRT: Shorter MCRT results keeps slower growing filaments from over taking desirable floc forming organisms.
  
• Disinfection: Use of hypochlorite or other oxidant chemistry can be used to damage filaments. Not an easy fix but can be used in times of critical performance issues.
  
• Bioaugmentation: Adding low temperature organisms with the ability to degrade FOG under winter conditions can help in systems with elevated influent FOG or extensive histories with cold weather foaming.
  

Embracing a more holistic approach for winter operations
Maintaining nitrifier populations while keeping winter's problematic filaments under control requires maintaining a delicate ecological balance. There is no single fix or program that replaces understanding and monitoring the complex ecosystem inside the MLSS. Using molecular tools gives vital details on even slight changes in populations and guides operators in adjusting wasting rates and other control options. It is best to monitor and catch problems before they result in increased chemical use or compromise treatment efficiency.

If you have any questions about molecular testing or foaming control options, you can contact us at [email protected] or visit our website at www.asterbio.com.

Much larger than bacteria, protozoa (single cell eukaryotes) and metazoan (multiple cell organisms) are easily seen with light microscopy at 10x and 40x objectives. Both are usually very active and easily spotted as they feed and move about the sludge. Meanwhile, individual bacteria cells look like tiny specs that bounce with water flow on the slide.

Floc, often referred to as "bugs" is composed of:

• Living and dead bacteria
• Extracellular biopolymers (EPS) functioning as glue creating a biofilm that serves to trap stored insoluble organics being acted on by extracellular enzymes and protecting cells from surrounding environment.
• Inorganics - EPS also contains grit and other inorganics trapped in the matrix

Both protozoa and metazoan prey on either free bacteria or graze on the floc. This grazing and filter feeding helps improve wastewater operation.

• Filter feeders remove free bacteria cells from solution and encourage floc formation by consuming cells not in the biofilm (floc). You can watch stalk ciliates actively filtering free floating cells while attached to floc. In the case of "young sludge" - high F/M - you will see flagellates and amoeba moving along consuming free cells.
• Grazing feeders move along developing floc and consume outer layers of the biofilm. Grazing feeders include free crawling ciliates, rotifers, water bears, and other metazoan. By grazing on the outer layers, these organisms reduce excess EPS and help keep the biomass active and aerobic. All are good for improving floc density and settling.
  
  

Can protozoa and metazoan "eat" key organisms in the system?
While it is possible, a healthy ecosystem contains both primary producers and predators. This relationship between predator and prey ensures no overgrowth of any single organism and a more diverse biomass. So, just note the indicator organisms present and relate activity to where the system is on the growth curve. Don't worry about protozoa or metazoan eating all the biomass.

Poster with indicator organisms and how they relate to the growth curve is available for download here
https://asterbio.com/bug-poster/

Non-filamentous bulking in wastewater treatment plants (WWTPs) can be a challenging issue, affecting the quality of the final effluent. In the photo above, note the rounded colonies that appear to have more "gel" between the cells - these are high EPS zones. Also, the above photo is using India Ink. The carbon particles in the ink do no penetrate high EPS floc which proves that you have excess EPS and non-filamentous bulking. Let’s explore strategies for controlling this phenomenon:

1. Understanding Non-Filamentous Bulking:
   • Filamentous bulking occurs due to excessive growth of filamentous bacteria in WWTPs.
   • Ideally, there should be a balance between filamentous bacteria and floc-forming bacteria.
   • In moderate amounts, filamentous bacteria contribute to AS settle-ability by providing a structural base for robust floc formation.
2. The Role of EPS (Extracellular Polymeric Substances):
   • EPS is crucial for floc formation in suspended growth and biofilms.
   • It consists of polysaccharides, proteins, nucleic acids, and metabolic byproducts.
   • EPS protects cells and accumulates nutrients (N, P, metals).
   • Proper EPS levels are essential for solids removal and phosphate removal.
3. The Transition to Excess EPS:
   • Excess EPS leads to problems:
     • Waste solids retain more bound water.
     • Dewatering becomes difficult.
     • Secondary clarifiers may have floating scum and poor compaction.
   • Major contributors to non-filamentous bulking:
     • Thauera: Common in industrial activated sludge.
     • Zooglea: More common in domestic wastewater.
     • Azoarcus: Less common but efficient denitrifiers.
4. Control Strategies:
   • Nutrient Adjustment:
     • Turn up nutrients (N or P) if not already optimal. If C:N:P ratio is in the target zone, adding additional nutrients will not help with bulking.
   • Waste Solids Management:
     • Remove excess EPS through waste activated sludge (WAS).
     • Be cautious as it increases the F/M ratio.
   • Bioaugmentation:
     • Increases viable microorganisms in the mixed liquor suspended solids (MLSS) breaking bottlenecks created by overgrowth of high EPS producing organisms.
     • Aster Bio has identified and produced cultures having the ability to degrade EPS via extra-cellular enzymes and form beneficial capsular polymers that function much like chemical cationic coagulants.
5. Monitoring and Early Detection:
   • Use molecular tests including qPCR to detect changes in Zooglea populations.
   • Look for signs of increased soluble BOD loadings at the influent.

Remember that effective control strategies require a combination of traditional and innovative approaches.