{"id":17586,"date":"2026-05-20T18:01:36","date_gmt":"2026-05-20T17:01:36","guid":{"rendered":"https:\/\/isleutilities.com\/?p=17586"},"modified":"2026-05-27T15:01:43","modified_gmt":"2026-05-27T14:01:43","slug":"cutting-wastewater-ghgs-what-real-time-n%e2%82%82o-control-can-actually-deliver","status":"publish","type":"post","link":"https:\/\/isleutilities.com\/it\/cutting-wastewater-ghgs-what-real-time-n%e2%82%82o-control-can-actually-deliver\/","title":{"rendered":"Cutting Wastewater GHGs: What Real-Time N\u2082O Control Can Actually Deliver"},"content":{"rendered":"

Nitrous oxide doesn’t get the attention CO\u2082 does, but for wastewater treatment plants it’s arguably the bigger problem. At some facilities, N\u2082O accounts for up to 80% of total greenhouse gas emissions; at around 275 times the warming potential of CO\u2082, it represents a significant liability for any operator with net-zero commitments.<\/span><\/p>\n

The difficulty is that N\u2082O is hard to manage because it has historically been hard to see. Most plants have relied on generic emission factors rather than site-specific measurements, making it nearly impossible to identify when and why emissions spike, let alone act on them in time. As national climate targets tighten and scrutiny of the water sector grows, that blind spot is becoming harder to justify.<\/span><\/p>\n

A recent Iniziativa sui bacini di prova<\/a> demonstration at Rennes M\u00e9tropole’s Beaurade wastewater treatment plant has shown that this problem is not only manageable, but that substantial energy and GHG savings don\u2019t necessarily require new infrastructure. What made the difference was both down to the technology and also the way the trial was structured: with defined success criteria, a committed end user, and a clear pathway from solution to adoption built in from the outset. Together, this is what separates a promising dataset from a working model that can be replicated at scale.<\/span><\/p>\n

What the trial set out to do<\/b><\/h3>\n

Rennes M\u00e9tropole has its own climate plan targeting a 42% reduction in greenhouse gas emissions by 2030. Given that N\u2082O is the largest direct emissions source at major treatment plants, reducing it is an obvious priority. The demonstration brought together Rennes M\u00e9tropole as end user, technology integrator Purecontrol, and ClimateTech startup Cobalt Water Global to test a combined measurement and control approach under real-world operating conditions.<\/span><\/p>\n

Cobalt Water Global and Purecontrol do different but complementary things, and their partnership was designed this way from the start. The two companies began collaborating in early 2022, sharing data from two French wastewater treatment plants to co-design a minimum viable product before Beaurade was on the table. Their pre-trial groundwork was crucial, as it meant the deployment at Beaurade wasn’t two technologies being introduced to each other on site.<\/span><\/p>\n

Cobalt Water Global’s contribution moves away from the industry’s traditional reliance on broad emission estimates. Instead, sensors installed directly in the aeration lanes generate continuous dissolved N\u2082O data, feeding a predictive model trained on site-specific conditions. At Beaurade, effluent flow rate, temperature and ammonium concentration emerged as the strongest predictors of emissions, yet this pattern would have been invisible without continuous monitoring.<\/span><\/p>\n

Purecontrol’s AI platform takes that emissions intelligence and acts on it. The two systems are connected via a purpose-built application programming interface (API), automating the data exchange between Cobalt Water’s N\u2082O risk modelling and Purecontrol’s real-time control platform. Purecontrol anticipates how key process parameters will evolve and adjusts aeration cycles accordingly, issuing updated control setpoints every minute. During peak electricity tariff periods, aeration is reduced to what is strictly necessary. During off-peak hours, the system aerates more actively to pre-empt the next demand peak, all while keeping effluent quality within compliance limits. One system identifies what is happening and why while the other decides what to do about it.<\/span><\/p>\n

It is worth noting how Purecontrol approached the question of competing priorities. Rather than treating energy efficiency and N\u2082O reduction as an inevitable trade-off, they designed a system flexible enough to optimise for either: an economic mode prioritising cost reduction within a defined energy budget, or an environmental impact mode focused on maximum GHG reduction. The choice of which to prioritise at any given time remained with Rennes M\u00e9tropole, which is an essential reassurance for utilities cautious about handing operational decisions to a third-party platform.<\/span><\/p>\n

For end users, this does more than optimise plant performance behind the scenes. It gives utilities a practical way to balance cost, carbon and compliance without pretending those priorities always point in the same direction, because they often don\u2019t, despite what glossy innovation decks like to suggest.<\/span><\/p>\n

It also gives operational teams greater control and confidence. By allowing Rennes M\u00e9tropole to choose between an economic mode and an environmental impact mode, Purecontrol keeps the utility in the decision-making seat. That matters because wastewater treatment is not a simple \u201cset it and forget it\u201d environment. Conditions change, priorities shift, and operators need tools that support judgement rather than override it.<\/span><\/p>\n

From an end-user perspective, the benefits include:<\/span><\/p>\n