Effective control of bulking
and floating sludge
Precise identification and quantification of filamentous bacteria directly in the sample -
quickly and reliably. The wastewater monitoring of filamentous bacteria enables efficient
and timely intervention before problems with bulking and floating sludge occur.
What are filamentous bacteria and why are they a problem?
Filamentous bacteria such as Microthrix parvicella, type 021N and other filamentous organisms are a natural part of the biocenosis in wastewater treatment plants. In controlled quantities they are harmless - they even help with floc formation. However, under certain conditions, such as increased fat content in the influent or insufficient oxygen supply, they can multiply excessively. The result: bulking and floating sludge.
Conventional control strategies such as the regular addition of precipitants are often costly, unsustainable and not always effective. Without regular monitoring, the growth of bacteria goes unnoticed until it causes visible problems.
VIT® gene probe technology enables the precise identification and quantification of microorganisms directly in wastewater. Microbiological wastewater monitoring enables targeted control of measures, optimum dosing of precipitants and preventive avoidance of bulking sludge.
Efficiently combat bulking and floating sludge
Without precise data on the causes and accurate knowledge of the type of problem-causing bacteria, control strategies can be inefficient or even counterproductive. Each type of filamentous bacteria requires specific countermeasures. For example, Microthrix parvicella responds positively to an increase in oxygen levels and the targeted addition of coagulants such as polyaluminum chloride (PAC). In contrast, bacteria like Type 021N require adjustments to sludge parameters for effective control.
Conventional analysis methods such as microscopic examinations or staining techniques do not provide reliable results. The morphovariability and similar morphology of filamentous bacteria complicate their clear identification. Additionally, PCR analyses are problematic as they cannot differentiate between living and dead microorganisms, and the complex composition of wastewater samples makes reliable quantification impossible.
The VIT® Gene Probe Technology overcomes these limitations by enabling precise identification and quantification of microorganisms through its unique and direct approach.
Microthrix parvicella
These filamentous bacteria can be combated by reducing the fat intake in the wastewater and increasing the oxygen level to over 2 mg/L in all aerobic zones in combination with increasing the sludge age. In addition, the use of aluminium salts or iron(III) salts can be helpful to promote the precipitation of phosphate and thus worsen the nutrient conditions for the bacteria.
Thiothrix spp. and Type 021N
Type 021N: Increasing the sludge load and the F/M (food to microorganism) ratio with adjustment of the sludge age and phosphate precipitation.
Thiothrix: Usage of sulphur-binding chemicals such as iron(III) chloride to bind hydrogen sulphide and control the bacteria.
Haliscomenobacter hydrossis
Can be controlled by increasing the sludge load and improving the oxygen supply. The addition of certain precipitants, such as aluminium salts or iron(III) salts, can also help.
Nocardioforme Actinomyceten
Possible control through the reduction of grease in the inlet and the use of precipitants such as aluminium salts or iron(III) salts. Improved aeration and an increase in the sludge load are also effective. The addition of surfactants can also promote the removal of bacteria from the surface.
Practical examples: AZV Südholstein / Hetlingen sewage treatment plant
- Challenge: Recurring bulking sludge caused by Microthrix parvicella with sludge volume indices exceeding 200 ml/g.
- Solution: Implementation of VIT® Gene Probe Technology, enabling optimized PAC dosing and early intervention.
- Result: Reduction of sludge volume index while simultaneously lowering operational costs.
Since 2004, AZV Südholstein / Hetlingen sewage treatment plant, Germany, has relied on direct microbiological monitoring using gene probes. This approach allows the plant to begin controlling bulking sludge at the first signs of an increase in disruptive filamentous bacteria, preventing a critical rise in filamentous organisms and a deterioration in effluent quality. As a result, PAC expenses have been permanently reduced, and the environmental impact has been alleviated.
Direct analysis
Fluorescence-labelled gene probes enable the specific identification and quantification of living cells - regardless of their morphology.
The microorganisms are recognised even at the lowest concentrations, long before they cause bulking sludge.
Target-oriented measures
The analysis provides precise data on the type and quantity of bacteria, which enables exact dosing of precipitants. Data is available within a few hours, enabling early intervention.
Efficiency and environmental protection
Optimised dosing of precipitants reduces costs and improves operating efficiency. Reduced use of chemicals relieves the environment and protects the plant's biocoenosis.
Regular monitoring with VIT®
Regular monitoring with VIT® allows for highly specific tracking of filaments. Countermeasures can be implemented before visible issues like bulking and floating sludge formation occur.
Regular monitoring can be conducted directly on-site using the products or as a service through our annual packages, which offer an optimal cost-performance ratio.
VIT® Test Kits Recommended by Experts:
VIT® Chloroflexi
VIT® Haliscomenobacter
VIT® Microthrix
VIT® Nocardia
VIT® Nostocoida limicola II
Laboratory Analysis - Bulking and Floating Sludge:
VIT® for Filaments
Filaments PLUS
Chloroflexi Analysis
Type 021N/Thiothrix Analysis
Microthrix Analysis
The advantages of monitoring with VIT®
Effective direct monitoring of microorganisms
Effective direct monitoring of microorganisms
Enables targeted process control
Increased operational reliability and stability of the wastewater treatment plant
Cost reduction thanks to timely and efficient use of countermeasures
Sustainable optimization of the cleaning performance
Without VIT® Monitoring
Poorer discharge values: Deterioration of sedimentation and pollution of the receiving water.
High operating costs: Due to high addition of precipitants such as PAC or aluminium salts.
Environmental pollution: Due to the high use of chemicals, which pollutes the sewage treatment plant and the environment.
With VIT® Monitoring
Efficiency: Targeted measures thanks to precise data. No unnecessary experiments, no waste of resources.
Cost savings: Optimised PAC dosing and fewer operational interruptions.
Environmentally friendly: Minimised use of precipitants reduces the impact on the biocoenosis and the environment.
Seminars & Webinars
We offer a broad range of webinars and seminars covering various aspects of microbiological wastewater monitoring. Our events provide theoretical knowledge and practical examples of monitoring and analyzing microbiological parameters.
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Webinar filamentous bacteria
As part of the webinar ‘Filamentous bacteria: Causes, effects, detection and control’, wastewater treatment professionals will gain valuable insights into the biological basis of filamentous microorganisms, innovative detection methods and strategies for control.
Nitrification
The conversion of ammonium to nitrate is carried out by specialised microorganisms - the nitrifiers. The process can be optimised through precise monitoring of the bacterial populations responsible for nitrification.
VIT® Vision software
With VIT® Vision, the entire biology of the wastewater treatment plant can be recorded, analysed, visualised and quantified. The results can then be implemented in the operational control system in order to optimise operational safety.