Use Case 5: Wastewater treatment

Different locations within the Use Case:

The monitoring and control of waste-water treatment use case will take place in different locations:

  • In Chennai the LOTUS sensor will be used in an algal-based wastewater treatment plant;
  • In Warangal the LOTUS sensor will be used in an innovate wastewater treatment plant.


  • Algal-based wastewater treatment has been confirmed as a suitable way to treat wastewater and to produce valuable substances, but so far has only been investigated experimentally investigated; therefore, the operating parameters are yet to be optimised.
  • Activated sludge wastewater treatment is an established technology that is used world-wide, but still has a large potential for improved energy efficiency and reduced pollutants in the outflow especially in high load conditions.

Scope of the use case:

The scope of the use case is to employ the LOTUS sensor to improve the operation of wastewater treatment plants. The following two subcases will be considered:

  1. Activated sludge treatment
  2. Algal-based wastewater treatment

Key aims for improving water quality for irrigation networks:

  • Achieve the desired effluent quality through highly efficient day-to-day operation;
  • Reduce as possible the operational cost of the wastewater treatment processes and in particular the demand for electric power;
  • Monetise the wastewater in the form of bio-fuels and fertilizers in order to make the best use of wastewater as a resource;
  • Maintain the effluent qualities for all weather conditions for varying influent qualities.

How LOTUS will improve monitoring and control of algal-based wastewater treatment plant:

The approach will rely on two main steps:

  • Validation of the LOTUS sensor as a tool to monitor the level of contamination at the different stages of the depollution process;
  • Use of the sensor as a tool to optimize the performance of the process, in terms of cost and depollution quality.

In Chennai:

  • Up to 3 sensors each will be integrated into the experimental facilities at NEERI (National Environmental Engineering Research Institute) in Chennai.

In Warangal:

  • Sensors will be integrated into experimental facilities at NITW (National Institute of Technology, Warangal, Telangana) in different locations.

Current developments:

  • NEERI Chennai fabricated one vertical and one horizontal reactor of 10 and 20 l for algal-based wastewater treatment studies.
  • NEERI, Chennai has placed an order for two raceway ponds (5000 liters and 1000 liters) with paddle wheels for pilot-scale algae-based wastewater treatment:
    • The parameters pH, temperature, TDS (Total Dissolved Solids), salinity, nitrogen, phosphorus, and D.O.  (Dissolved Oxygen) will be measured online.
  • With the goal of advanced control of the plants at NEERI, simulation studies are performed at TU Dortmund.
    • A suitable model of the process has been identified from the literature;
    • A state estimation scheme (Extended Kalman Filter, EKF) has been developed and tested in simulations.
  • Currently TUDO and NEERI are communicating to decide on the actuations that will be implemented at the plant.
  • The ultimate goal is the implementation of a nonlinear model predictive control scheme of the process based upon TUDO’s nonlinear NMPC technology.
  • An experimental facility is being set up for biological wastewater treatment at NIT Warangal for evaluating the LOTUS sensor and its use in closed-loop control algorithms with the goal to improve the efficiency of the process. Nitrate and DO will be controlled at certain locations.

Outcomes of Use Case 5:

  • Sensors will enable to demonstrate and improve the efficiency of innovative water treatment plant,
  • Treated water can then be safely rejected in the natural environment.