Monthly Archives: March 2013

[IT-EN] …most used links…

[EN] WWTP/check: Checking Procedure for Biological Nutrient Removal Processes with evaluation of possible Energy/Cost Saving in pre-Denitrification/Nitrification scheme

WWTPWWTPcheck – Math Model 

Nitrogen Removal and Control Strategy in Continuous-Flow-Aeration 

WWTPcheck Model is based on typical Mathematical Models referring in the field (ASM 1/2/3, WPRC), but it supplemented with Performance Indicators (KPIs), which also provide information on the Residual Depurative Capacity. The predenitrification process was first developed and proposed by Ludzack and Ettinger (1962) and later modified by Barnard (1973), who completely separated the anoxic and aerobic reactors, recycling the settler underflow to the anoxic reactor, and providing an additional recycle from the aerobic to the anoxic reactor, see Figure below:


WWTPcheck Flow scheme:  Modified Ludzack-Ettinger process (Denitro/Nitro)

Main Functionalities of Evaluation of WWTPcheck  procedure:

  • Percentage of Performance of Biological Nutrient Removal Process.
  • Min/Max values of Dissolved Oxygen required to avoid process problems (bulking, etc.).
  • Characterization of Functional Parameters of the Aeration System.
  • Percentage of possible Energy Saving in the Aeration System (variable DO setpoint calculation on the base of min/max biological need…).
  • Energy required for Aeration System.
  • Percentage of Electrical Energy Cost Saving.
  • Percentage of Sludge/Waste produced and their Cost.
  • Customized Input/Output Reporting.

The WWTP/check procedure is  available in MS-Excel file (.xls or .xlsx – MS Office-Excel 2007 or compatibles) to be better used as a checking tool and test.


For info or for a quote:

[IT] Water Regulations

  • Dlgs_152_06_agg2010 – Decreto legislativo 3 aprile 2006, n. 152 – Norme in materia ambientale (G.U. n. 88 del 14 aprile 2006)

MBBR/IFAS Model: Math Procedure for Upgrading of existing WWTP by using Carrier

Hydroxyl-Pac (biofilm growth under magnification) TRANSPARENTThe  Mathematical Procedure aims at to  evaluate  the capacity of the purification, in terms of removing carbon and nitrogen (C, N), in pre-existing activated sludgeplants (AS), avoiding structural modifications on biological reactors volume, but integrating them with IFAS/MBBR (Moving Bed Biofilm Reactor) technological solution. The functionality of the biomass suspended (MLSS) is enhanced with an additional system to immobilized biomass, through the use of a system consisting of granular plastic supports high ratio surface/mass  (Carrier). The added Carrier creates a natural habitat for the development of a biofilm layer (adherent biomass), mainly responsible for the phenomena of nitrification of ammonia contained in the sewage to be purified. The IFAS math procedure, although starting from technical-scientific and experimental approach available in the literature, it is defined by a heuristic model that allows to determine the “equivalent effect induced” as process IFAS / MBBR, or the”virtual increase in volume” of the reactor AS (ie concentration of total biomass), as a result of the integration process with the immobilized biomass in IFAS.

In other words, the WIFAS procedure assimilates the reactor AS, enhanced with the process IFAS, to a “increased” reactor volume, having a final behavior equivalent to that of a dimensional expansion of the initial reactor AS.
The WIFAS math procedure integrates SWater or WWTP/check code.


The IFAS procedure is also available in MS-Excel file to be better used as a checking tool and test.


For INFO and a quote: