Building Nosedo WWTP system’s resilience with Hubgrade digital solution

| THE CHALLENGE

Drought conditions drastically reduce the water resources available in Italy and other countries in southern Europe, jeopardizing water supplies for household use, agriculture and energy production. 

Fighting water scarcity through water reuse has a lot of potential, especially in Italy. However, currently, only 4% of wastewater is destined to be reused directly, when the potential is 23%1

One municipality ahead of the game is Milan Water Service, MM SpA. “The main characteristic of the Nosedo plant is the large volume of water treated that is reused for agriculture. The Nosedo WWTP is one of the best examples of water reuse in Europe. Our challenge is to guarantee every time the best condition for the water reuse.” — Andrea Aliscioni, COO Milan Water Service.

That is why wastewater is treated “not only according to environmental directives, but also for the possibility to have a circular use of the water.” — Francesca Pizza, Process Manager at Nosedo WWTP.

| THE SOLUTION

Hubgrade Performance is a holistic digital monitoring system that optimizes processes to make water processes smarter, safer and more sustainable. It is composed of a suite of intelligent software solutions for real-time optimization of process performance. It provides a state-of-the-art auto-pilot to optimize the whole wastewater system, including the sewer network and treatment plant.

For Nosedo, Hubgrade Performance provides critical water quality data by providing  real-time automated optimization of the consumption of energy and chemicals, biological and hydraulic capacity enhancement. It not only ensures stable operation and compliance of wastewater treatment plants and sewer networks but it builds network resilience by managing high load variations.

| THE CLIENT

Nosedo Wastewater Treatment Plant (WWTP) is Milan’s main municipal wastewater treatment plant. It has a capacity of 1,250,000 population equivalent (PE) with full nitrification and denitrification and is one of the best examples of water reuse in Europe as up to 70% of its treated wastewater is reused  for agricultural purposes.

  • 350,000 cubic meter (m3) treated a day
  • 5 m3 per second (/s) treated during dry weather
  • 15 m3/s during rainy events
  • 60% to 70% of the treated water is directed to agriculture
  • Treatment plant load: ​​​​​​​
    • 2017: 980,000 population equivalent (PE)
    • 2023: 1,180,000 PE

| CLIENT BENEFITS

Why Hubgrade Performance

  • A digital solution that was directly integrated into the operation of the sewer network and the WWTP.
  • Nosedo wastewater treatment facility achieved annual operational costs savings of more than €1,500,000 per year from energy, chemical and sludge reduction.
  • Strengthened resiliency by better handling high load variations with a full  overview and less manual adjustments.
  • Achieving 20% higher hydraulic capacity in biology, giving a better handling of wet-weather events.
  • Having high flexibility for future plans (with the ability to also cover the whole Milan sewer system).

All the above benefits have been achieved with a higher load than before the implementation which has moved from 80% to 100% of the design capacity load.

Additional client benefits

  • Important CO2  equivalent reduction thanks to the various savings.
  • ​Smart Bio-P: Introduction of significant biological phosphorus removal in existing process volumes in a WWTP not designed for it.

One of the most significant challenges WWTPs face is gaining as much control as possible of the biochemical process. With 40% of the total plant energy consumption “it is the most demanding [process] from an energy point of view. Hubgrade Performance allows operators [to] have an instrument to make real time decisions on the process.” — Francesca Pizza.

Potential additional features 

To support the enhancement of the hydraulic capacity:

  • Stormwater with rain and sewer measurements
  • Maximum flow inlet biology

 ‘Hubgrade Performance [...] boosts our performance by increasing the hydraulic capacity during wet weather. It is a smart solution with a high effect.’
Andrea Aliscioni

 

1The European House – Ambrosetti “The value of water for Italy” – report 2023

KEY FIGURES
The performance guarantee analyses led to the following results (last two years average): 

  • CO2 savings (approximately 2,800 tonnes (T) CO2-equivalent per year (equ/year)
  • Electricity: 1,900T CO2 eq/year
  • Chemicals fabrication: 230T CO2 2 eq/year
  • Transportation: 100T CO2 2 eq/year
  • Effluent charge: 550T CO2 2 eq/year
     
  • OPEX savings (approximately €1,800 per year): 
    • Energy savings:
      • Biology: 0.431 reduced to 0.302-kilowatt-hour per kilogram (kWh/kg) chemical oxygen demand removed
      • Grit chamber aeration: 50 reduced to 44H
    • Chemical savings: coagulant (FeCl3) usage reduced by 58%, going from 3.01 kg of chemical per kg of phosphorus removed to 1.28. 
    • Chemical sludge reduction: solid sludges reduced by 114  T per year due to less coagulant usag

Guaranteed savings: €400,000 an increase of 350%

  • Effluent quality
    • 29% reduction of total nitrogen (tot-N) in effluent from 7.1mg/l to 5.02mg/l tot-N
    • Increased hydraulic capacity 
    • During wet weather: 20-30

The HubgradeTM Performance Plant package for Nosedo WWTP includes the following features:

  • Dissolved Oxygen and nitrogen removal
  • Mixer (denitrification tank)
  • Air supply, blowers and grit chamber aeration
  • Return activated sludge and NO3 recirculation
  • Solids retention time
  • Standby (biological lines)
  • P-precipitation

NB: We did not integrate the potential Italian carbon tax (€60 per tonne of CO2 - Organization for Economic Co-operation and Development) which would add another €170,000 per year of extra savings.