Wastewater treatment targets deemed undeliverable

Key government targets to improve wastewater treatment have been deemed largely undeliverable in a leaked document drawn up by the Department for Environment, Food and Rural Affairs (Defra).

The document, seen by Utility Week, was presented to ministers including energy secretary Grant Shapps ahead of last week’s “Green Day” announcements which included the government’s response to Chris Skidmore’s net zero review, which in part sets out measures to improve wastewater treatment.

The 10-page advisory document, first reported by The Times, assesses the “delivery risk” and “delivery confidence” of each of the net zero measures proposed by Defra.

Each measure is given a traffic-light rating of green, amber or red (with green meaning there is a high probability of a measure being delivered and red meaning that delivery is unlikely). Of 44 policies, only five were given a green rating. A further 21 were marked as red or amber/red with 18 policies graded as amber or amber/green.

In total, 42 of the 44 policies appeared in the Green Day announcements despite the warnings around deliverability.

There are four measures listed within the Defra document relating to wastewater treatment. None of the measures are given a green rating, with one graded as red, two listed as amber/red and one marked as amber/green (see table below).

In all cases, Defra has ruled that the risk to deliverability is because there is no legislation driving the measure and it has been left up to the water industry to implement the relevant processes.

The least likely measure to be delivered, according to the Defra assessment, relates to the development and adoption of new wastewater treatment processes to improve the efficiency of wastewater treatment and reduce greenhouse gas production; in particular the use of anaerobic treatment, Membrane Aerated Biofilm Reactor and alternative ammonia removal processes.

Defra graded this as red because it “is dependent on the water industry investing in the processes” and “there are no legislative requirement driving this”. However, the assessment document adds that the Regulators Pioneer Fund established by the now defunct Department of Businesses, Energy and Industrial Strategy would assist the delivery of this measure with projects due to finish by March 2025.

Measures given an amber/red rating include targets to treat a higher proportion of sewage sludge via advanced anaerobic digestion and increasing the use of new sensors to monitor emissions from wastewater treatment.

In relation to the use of sensors to monitor emissions, Defra’s assessment ruled that more needs to be done to ensure that “water companies are able to understand the emissions from different treatment processes and how they vary with environmental conditions/ load/ location”.

The Defra assessment adds: “To do this we need further research and the development of techniques to monitor GHG [greenhouse gas] emissions. The Water Industry holds responsibility to drive through existing industry tools and processes such as the WINEP [Water industry national environment programme], UKWIR [UK Water Industry Research] and opportunities from regulator driven funding mechanisms such as the Ofwat Innovation Fund.”

The final measure within the Defra briefing was rated as amber/green and relates to improving data modelling and collection to improve reporting and reduce uncertainty around industrial wastewater treatment emissions.

Despite Defra’s concerns, water companies have made some progress on monitoring wastewater in recent years. Utility Week recently visited Severn Trent’s Minworth water treatment plant in Birmingham where the water company installed the first monitoring devices in the UK to understand emissions from treatment processes.

Water companies are also due to submit the final versions of their Drainage and Wastewater Management Plans (DWMP) in May.

It is the first time water companies have been required to draw up such a plan which will detail long-term plans for meeting storm overflow targets as part of 25-year investment planning.

The deliverability of the government’s Green Day announcements has also been called into question by key industry figures.

Earlier this week, Utility Week reported on how industry is concerned that government departments, such as the Department for Energy Security and Net Zero, are not sufficiently staffed to deliver on all the pledges outlined by energy secretary Grant Shapps.

At risk measures identified by Defra:

*Table adapted from Defra briefing document