A young sludge produces white, fluffy foam in the aeration basin of the treatment plant. Excessive amounts of fats, oil and grease (FOG) or some other chemicals can cause the growth of foam-forming filamentous bacteria. Wastewater
Wastewater
Wastewater, also written as waste water, is any water that has been adversely affected in quality by anthropogenic influence. Wastewater can originate from a combination of domestic, industrial, commercial or agricultural activities, surface runoff or stormwater, and from sewer inf…
What is wastewater foam and why is it a problem?
While it’s common for a treatment plant to have some wastewater foam, the problem occurs when there is so much foam that it hinders the plant’s operations. What Causes Wastewater Foam? Excessive amounts of surfactants in the wastewater can generate foam.
How do you get rid of wastewater treatment plant foam?
Since every wastewater treatment plant is different, there’s no one-size-fits-all approach to reducing foam. That said, there are four main solutions that have been proven to work time and again: spray the foam, physically remove the foam, add chemicals or bioaugmentation. 1. Spray the Foam
Why is there foam in my plant?
The cause of foaming should never be assumed. If there is foam in your plant, it is recommended to perform a microscopic evaluation of the foam and mixed liquor. As a general rule, if the organism is much more concentrated in the foam than the underlying MLSS, this can be associated with the foam.
What causes white foam in a sewage treatment plant?
A young sludge produces white, fluffy foam in the aeration basin of the treatment plant. Excessive amounts of fats, oil and grease (FOG) or some other chemicals can cause the growth of foam-forming filamentous bacteria.
How do I stop foaming in wastewater treatment?
Common strategies for foaming control include: Reduction of SRT (Sludge Retention Time, similar to mean cell retention time, often used in wastewater treatment operation) to wash out filamentous bacteria; removal of hydrophobic substances and substrate that could enhance foaming or favor the growth of filamentous ...
What causes foaming in activated sludge treatment plant?
Biological foam is due to operating conditions in the wastewater treatment plant. It accumulates on the surface of the aeration basin and may carry over into the final clarifier and effluent discharge.
What is sludge foaming?
The filamentous bulking effects are: high Sludge Volume Index (SVI), low solid concentration in the return and waste sludge and hydraulic overloading of solids handling systems (EPA, 1987). Sludge foaming is a condition in which various kinds of foam appear on the surface of the aeration and clarification tanks.
Why is my septic tank foaming?
Surfactants typically cause foaming or suds in water. Anionic surfactants have poor anaerobic degradability in the septic tank and may inhibit hydrolysis at 10 mg/L. Slow hydrolysis may cause the accumulation of solids in septic tanks and therefore may necessitate larger system design for adequate wastewater treatment.
What kills foam?
Vinegar and salt are both great at reducing the foam caused by detergents for hand washing. Salt reduces the surface tension of the water which inhibits the production of suds. The dishwasher should then be forced through a rinse cycle.
How do you settle foam?
0:091:36How To Get Rid of Beer Foam Fast - YouTubeYouTubeStart of suggested clipEnd of suggested clipEven your oily nose work in a pinch get a dab of grease on your finger. And swirl it through theMoreEven your oily nose work in a pinch get a dab of grease on your finger. And swirl it through the foam to watch those bubbles disappear.
What is the cause of bulking of sludge?
Sludge bulking is the most common solids settling problem in wastewater treatment plants, which is caused by the excessive growth of filamentous bacteria extending outside the flocs, resulting in decreasing the wastewater treatment efficiency and deteriorating the water quality in the effluent.
What causes foaming in bioreactors?
Foaming in bioprocesses Foam occurs in bioprocesses due to the introduction of gases into the culture medium, and is further stabilised by proteins produced by organisms in the culture[1]. Foam is made up of liquid lamellas which are full of gas.
What causes filamentous bacteria in wastewater?
Filamentous bacteria are able to predominate under low dissolved oxygen, low F/M, low nutrient conditions or high sulfide levels. However, it appears that low F/M is the predominant cause of bulking in wastewater treatment plants.
What is MCRT in wastewater?
The mean cell residence time or MCRT is the amount of time, in days, that solids or bacteria are maintained in the activated sludge process. The MCRT is known also as the solids retention time (SRT).
What are signs of septic tank problems?
Signs of Septic System FailureWater and sewage from toilets, drains, and sinks are backing up into the home.Bathtubs, showers, and sinks drain very slowly.Gurgling sounds in the plumbing system.Standing water or damp spots near the septic tank or drainfield.Bad odors around the septic tank or drainfield.More items...
Why is foam not the same in wastewater?
Due to the fact that every manufacturing or processing plant has different components in its wastewater, all foam in wastewater is not identical. There are many factors that contribute to developing foam during industrial processing or in the wastewater treatment process.
What are some things that involve foam and bubbles?
Daily processes in our lives like taking a shower, drinking a carbonated beverage, and shaving often involve foam and bubbles. Just imagine drinking an ice cold coke with no carbonation or taking a shower or bath with no bubbles.
What is the job of a defoamer?
In simple terms, the surface tension needs to be reduced, thus “popping” or preventing bubbles. This is the job of the defoamer or anti-foaming agent . To determine the proper defoamer needed for a particular process, many factors must be considered.
Is foam used in industrial processes?
In fact, developing foam in industrial processes is very common, especially in the production of adhesives, textiles, inks, paints, chemicals and other products. Foam also often develops in many food processing and municipal wastewater treatment applications as well. The development of foam can create many problems not only in production, ...
What causes foaming in wastewater?
Filamentous Foaming. There are three filaments that are known to cause foaming and these grow due to high amounts of fats, oils, and grease present in the wastewater. Septicity helps convert fats, oils, and grease to unsaturated forms, which are easier for these organisms to assimilate.
What is the problem with a wastewater treatment plant?
Filamentous foaming is a major cause of problems in wastewater treatment plants all over the world. Nocardioform and Microthrix parvicella foams are often controlled by lowering the sludge age. Chlorination of the RAS line is sometimes successful as well. Type 1863 grows at very young sludge ages (3-4 days or less).
What causes denitrification foam?
Denitrification is caused by anoxic conditions (no free dissolved oxygen), the presence of nitrate, and a carbon source (readily available BOD). Denitrification foams are common in the final clarifier and a major cause of effluent TSS violations.
Can de foaming chemicals be used in water?
For certain cases, such as filamentous foam, a chlorinated water spray has been successful. De-foaming chemicals are useful for surfactants that can’t be controlled at the source (common in industries such as paper mills). De-foamers do not eliminate the cause of foam, but can help keep foam from overflowing the basin.
Can filamentous foam be trapped in aeration tank?
Filamentous foams should not be trapped in the aeration tank or recycled back to the head of the plant. Wasting of filamentous foams to digesters can cause foaming in the digesters. Physical control of foams through sprays is difficult, but it has been done.
Can you assume the cause of foam?
One should never assume the cause of a foam and make operational changes until the foam has been properly identified. Long term control of foaming problems involves removing the cause of the foam at the source. There are different control strategies for different types of foams and improper control strategies (such as chlorinating a zooglea foam) ...
Can you remove filamentous foams with a vac truck?
If it is possible, it is recommended to remove filamentous foams with a vac-truck and not let them accumulate on the surface of the aeration basin. At MDG, we believe we have found a culture that can outcompete filamentous bacteria for fats, oils, and grease.
Why Is Wastewater Foam a Problem?
When there is too much wastewater foam in an aeration tank, it can overflow and get all over the equipment, railings, floor, and other areas. In extreme cases, the foam may damage electrical equipment and/or create safety issues by making walkways slippery.
How to Reduce Wastewater Foam: 4 Solutions
Since every wastewater treatment plant is different, there’s no one-size-fits-all approach to reducing foam. That said, there are four main solutions that have been proven to work time and again: spray the foam, physically remove the foam, add chemicals or bioaugmentation.
Conclusion
While it’s normal to have some wastewater foam in your treatment plant, having too much of it is a problem. Luckily, there are solutions available to reduce foam that are both quick and cost-effective.
Examples: How Bioaugmentation Products Are Used to Fight Foam
MICROCAT-DF is a biocompatible liquid defoamer that you dose into the wastewater to reduce the foam with a chemical reaction. It’s formulated for aeration tanks and sludge digesters to reduce foam without inhibiting the biomass or causing other negative side effects typically associated with conventional defoamers.
All Answers (10)
It seems the wastewater is not treated well before disposing in the lake.
Similar questions and discussions
What can be the reason for increasing COD while decreasing TOC in water?
Can chlorination cause filaments to grow back?
Chlorination is only a quick fix. Without process changes, filaments will grow back after chlorination. Wastewater Biomass Analyses and Cooling Tower Analyses also available.
Do wastewater treatment plants have foam?
The common misconception is that if you have foam on the surface of your aeration basin, you must have Nocardia. Not all wastewater treatment plants or systems have foam due to Nocardia- Some have Microthrix- Some just have too many solids and some low D.O.. . . . . .. . Some have zoogleal bulking.
Is foam bad for basins?
Not all foam is bad -but it usually indicates a condition that is going on in your basin- learn what the colors mean. . . . These are the typical troubleshooting foaming charts- be careful though and use your microscope or you may make the wrong interpretation as to what is causing the foam and how to fix it.
Physical and Chemical Environment
- Gas bubbles
From the mechanism for foaming mentioned above, we know gas bubbles are essential in foam generation. Gas bubbles are involved in many steps of activated sludge process. In aeration tank, aeration and mechanic mixing is employed to ensure enough dissolved oxygen for aerobic degr…
Key Microorganisms
- Filamentous bacteria serve as hydrophilic particles which play important role in stabilizing foaming in WWTP. There are two main groups of filamentous bacteria: the most commonly observed group: Candidatus Microthix parvicella , and members of the Mycolata.
Microbial Processes
- Substrate Storage
M. parvicella and Mycolata were reported to be able to utilize various organic compounds as carbon and energy source. The compounds contain organic acids, complex substrates and fatty acids under aerobic, anoxic and anaerobic conditions. The substrates can then be storaged intra… - Cell Surface Hydrophobicity and Exoenzyme Activities
Higher cell surface hydrophobicity were found in cells of M. parvicella and Mycolata than other bacteria in activated sludge. The more hydrophobic cell surface enable filamentous bacteria better attraction to hydrophobic substrates like lipids, long-chain fatty acid (LCFA). Additionally, …
Foaming Control Strategy
- There are no universal strategies effective for foaming control in WWTP. Specific measures need to be taken according to the reason of foaming, organisms involved and operational condition. Common strategies for foaming control include: Reduction of SRT (Sludge Retention Time, similar to mean cell retention time, often used in wastewater treatment operation) to wash out filament…
Current Research
- Identification of Filamentous Bacteria
Traditional identification of filamentous bacteria relies on their morphology under microscopy. However, many filamentous bacteria may not have distinguishable morphology, therefore, identification based on 16S or 23S rRNA genes are preferred. Nielsen group from Denmark devel… - Development of Effective Foaming-Control Chemicals
Conventional oxidizing chemicals like chlorine that used to destroy filamentous bacteria also affect the growth of other bacteria in activated sludge. More selective chemicals for controlling filamentous bacteria are desired. Polyaluminium chloride (PAX-14) was found effective in contr…
References
- Jenkins, D, Richard, MG, Daigger, GT. 2004. “Manual on the Causes and Control of Activated Sludge Bulking, Foaming, and Other Solids Separation Problems”, 3rd edition.. Lewis Publishers, New York.http://www.iwapublishing.com/template.cfm?name=isbn1843390469 Hug T. 2006. “ Characterization and controlling of foam and scum in activated sludge systems”. ETH Ph.D. Diss…