The N and P problem

Robert Colvile has a useful CAPX piece on EU environmental laws still holding back UK housing.


The Government is right to reform EU laws that are holding back housing

The Government has today announced that it is reforming EU laws designed to protect ‘nutrient neutrality’, in a move that ministers claim will unblock over 100,000 homes. But unless you are something of a housing policy obsessive, you may not know what this dry sounding directive is. So what is nutrient neutrality? How does it work? Why does it matter? Make yourself an instant expert with this handy guide…

The story starts with the EU Habitats Directive (1992). This set up a Europe-wide regime to protect, and if possible revive, particularly valuable sites and plant/animal species. There are now 658 such Special Areas of Conservation [SACS] across the UK – listed here.

Then, in 2018, came the ‘Dutch case’ (or ‘Dutch N case‘). This was an ECJ ruling which held that grazing cattle or applying fertilisers near such sites could only be done if ‘there is no reasonable scientific doubt as to the absence of adverse effects’.

This had a convulsive effect on Dutch politics. To avoid pollution, housing developments were halted, and farmers were told they’d have to lose half their cows and in some cases close their farms. There have been mass protests, farmer suicides, and the formation of a new populist party.


The whole piece is well worth reading as a reminder of several issues. The political overview point of Brexit is one. Another is the general inability of environmental organisations and pundits to accept the reality of trade-offs. Another is that a rising population will increase the volume of wastewater discharges containing nitrogen and phosphorus 


While the Dutch ruling was originally about nitrogen (from fertiliser), Natural England have expanded it to include phosphates. It’s also been applied to ‘recreation impacts’ – which, as I wrote in The Sunday Times, means housing can be blocked to protect the countryside from the devastating impact of people walking on footpaths or children building dens...

So expect headlines about evil Tories planning to destroy the environment, but that’s absolutely not what this is. This is the Government trying to deal with malign consequences of well-intentioned regulation while retaining all necessary protections for conservation sites.


This article from 2018 gives some perspective on the daunting complexity and technical difficulty of reducing phosphorus levels in wastewater treatment systems, particularly smaller systems. These tend to be located in more rural areas which are likely to be more environmentally sensitive.


Delivering effective N and P removal simultaneously appears technically difficult, especially at small-scales where factors such as space limitation and the need for system simplicity means that traditional methods may not work. A few emerging technologies offer some potential in this area, although often at the expense of the simplicity and-or energy requirements for effective operations.