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Wastewater Treatment Systems at the forefront of Nutrient Neutrality development

What is Nutrient Neutrality?

To understand the concept of nutrient neutrality it is important to acknowledge that nutrient pollution is an urgent problem for freshwater habitats and estuaries which provide a home to wetland birds, fish and insects. New guidance is aimed at areas with surface waters that are impacted by high levels of the contaminants, primarily phosphate and nitrate, which are present in treated wastewater that is discharged to watercourses in the final stage of the recycling process. The contaminants, often referred to as nutrients, can lead to increased growth of algae, which can have a detrimental impact on water environments and ecosystems - a process known as eutrophication.

Nutrient neutrality regulations first came into effect in 2019 when Natural England started issuing advice to local authorities with vulnerable and protected waters to only grant planning permission to new property developments proven to be ‘nutrient neutral’.

Nutrient neutrality is a means of ensuring new developments do not increase the nutrient burden of nearby protected waters. In the affected regions, developers must prove their plans would be neutral by demonstrating in planning applications how they would remove or offset the full amount of nutrients anticipated.

How will property developers achieve Nutrient Neutrality?

For properties that are not on mains drainage, onsite wastewater treatment systems can be a significant part of the neutrality equation. As such, wastewater treatment specialists RA Dalton have seen a huge increase in enquiries about which packaged wastewater treatment plant can remove the most nutrients. Here at Direct Drainage, we only sell Sewage Treatment Systems that meet British standards for nutrient removal. For example, the Klargester BioDisc removes 48% Phosphate and 46% Nitrates. By comparison, a septic tank would have no positive impact on levels.

Domestic Sewage Treatment Systems are pre-manufactured, whereas commercial systems can be custom built. All of the systems we sell are fully compliant with Environment Agency regulations, which mean final effluent can be safely discharged to a soakaway or watercourse. We can provide certificates of performance for any system to assist in the nutrient neutrality planning application. Importantly, the treatment process uses no chemicals, which is kinder to the environment and is far safer, particularly in a domestic environment.

Developers will also be able to purchase ‘nutrient credits’ which will discharge the requirements to provide mitigation. Natural England will accredit mitigation delivered through the Nutrient Mitigation Scheme, enabling Local Planning Authorities to grant planning permission for developments which have secured the necessary nutrient credits. This will ensure developers have a streamlined way to mitigate nutrient pollution, allowing planned building to continue and creating new habitats across the country.

Developments in Nutrient Neutral Sewage Treatment Systems

Off-mains sewage treatment systems are effective in removing a significant amount of nutrients, however, housing developers must accept that there is currently no technology suitable for domestic use that would remove 100% of containments. Nutrient neutrality can only be achieved through a combination of measures and in most cases offsetting – removing nutrients elsewhere in the catchment - will have to be considered, which local planners can advise on.

With the environment at the heart of Direct Drainage, we champion manufacturers that are undertaking research and development to find further low-impact ways to remove more nutrients without the use of chemicals.

Technology currently being researched includes absorbent beads made from zeolite, a natural occurring mineral which will safely remove phosphorous. Elsewhere, WPL are trailing the use of ultraviolet light in treatment units to create a suitable environment for the growth of algae, which itself removes phosphorous, and can be retained in the sludge produced for removal by the waste carrier.

While the issue of nutrient neutrality is complex and the guidance under constant review, some effective mitigation schemes have taken place to the benefit and relief of developers, and we are confident of technological advancements emerging soon.

Property developers facing the issue of nutrient neutrality should read Natural England’s guidance carefully, seek professional advice and of course contact Direct Drainage for clear technical advice on wastewater management solutions on 01388 537 050 or email