Tag Archives: Activated sludge

[EN] WDOxy/Fuzzy-control for improved Nitrogen Removal and Energy Saving in WWTP with predenitrification


Application of fuzzy-logic to improve the control of the activated sludge process. WDOxy-Controller is a dynamic (non-deterministic/fuzzy) approach model to “Dissolved Oxygen Control Strategy” in wastewater nutrient removing, basically based on using of Ione Selective (NH4+, NO3-) on-line analyzers, but in option it is possible to use on-line ORP/pH (Redox potential) low-cost sensors too. Fuzzy-logic based control strategies for wastewater treatment plants with pre-denitrification should lead to better effluent quality and, in parallel, to a reduction of energy consumption. The WDOxy goal is to develop a “dynamic DO set-up on need” calculation able to provide a continuous nutrient removal process control, under legal outlet limits and within a sustainable energy saving control. Compared to the operation with fixed nitrification/denitrification zones and constant DO concentrations, the required air-flow could be reduced up to 24% by using fuzzy-logic based control strategies. In fact, Traditional “DO Closed Loop Control” (aeration control) is a well-known automation procedure that does not allows to timely face the real need of oxidation that biological process dynamically requires from time to time. On the contrary, WDOxy control is able to face DO requirement, in all nutrient removal biological processes (N and P), in a cost efficient way, that means, by dosing energy on the base of a real-time evaluation of biomass metabolism.


The WDOxy fuzzy-controller procedure can be easily implemented in modern control and supervision systems and  the control characteristics can be followed and modified during operation.


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[EN-IT] MICROexpert: Activated Sludge Diagnostic Tool

MICROexpert: an effective Professional Tool to prevent solid separation problems

MICRO MICROexpert- Technical Sheet

MICROexpert is a knowledge based software tool for diagnosis and trouble-shooting of operational problems in activated sludge. It deals with suspended-solid systems in aerobic or in nutrient removing (N and P) processes, in CSTR (Continuous Stirred Tank Reactor) or Plug Flow reactors. The main goal of this tool is:

  • Detecting, at the right time, functional instability and anomalies in  progress;
  • Advising on possible corrective operations to prevent solid separation problems (bulking, foaming, rising, pin point floc, etc.), and therefore,
  • Avoiding failures of effluent quality.




A holistic approach to diagnosis MICROexpert major strength is its data-fusion, which is the ability to  merge consistently different type of data and information to the best diagnosis:

  • Microscopic sludge analysis on microfauna, sludge biotic index (SBI), sludge floc morphology and filamentous bacterial growth;
  • Laboratory physico-chemical analysis;
  • Operative parameters evaluated on field;
  • Visual investigation on efficiency of each wastewater treatment.

Incubation period and real-time process control MICROexpert exploits the peculiar “slow” dynamics of activated sludge and its incubation time (days before the effects of biological undesiderable anomalies) to predict diagnosis. Infact, a problem could not be promptly detect before it has occurred, by the only physico-chemical parameters. Generally, an incubation period is a considerable lapse of time…  This period (sometimes weeks), has to deal with a lack of a timely diagnosis!



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