Toxicity Detection of the biological process of Urban WWTP by On-line Respirometry

How SICTOX Optimizes the Biological Process and Avoids Contaminations

1. SICTOX

SENSARA’s SICTOX algorithm detects toxicity episodes and prevents them from entering the plant, thus protecting the biomass.

• • Toxicity tests last 95 minutes and are performed in two stages:
    1. Mixed liquor + Substrate (NH4Cl) → Nitrification rate.
    2. Mixed liquor + Substrate (NH4Cl) + Input sample → Nitrification rate.

The graphs obtained are as follows:

Nitrification rate 1 >>> Nitrification rate 2(% INH = 82%).

• 1. Mixed liquor + Substrate (NH4Cl) -> Nitrification rate 1
  2. Mixed liquor + Substrate (NH4Cl) + Mtra input -> Nitrification rate 2

Nitrification rate 1 ≈ Nitrification rate 2(% INH =.1%).

1. Mixed liquor + Substrate (NH4Cl) -> Nitrification rate 1
2. Mixed liquor + Substrate (NH4Cl) + Mtra input -> Nitrification rate 2

2. START-UP

2.1 Optimization phase:

For one month the system operates in pilot mode to optimize the tests and commands of the SICTOX algorithm.

2.2 Programming

After optimization, control is programmed in the plant SCADA.

• • • Divert water to quarantine if they are met at the same time:
      1. Value of % Inhibition > 60%.
      2. Accumulated volume > 5000 m³.
    • Stop diverting water if any of these conditions are met:
      1. Accumulated volume < 5000 m³.
      2. Value of % Inhibition < 60%.
    • For quarantine water lamination:
      • Pump to the biological at 10% of the flow rate.
      • Stop pumping if the nitrification rate AUR < 2.

2.3 Spill detection

Once the system has been optimized and programmed in the PLC of the respirometer and the SCADA, the control with SICTOX is started.