Architects urged to get their hands dirty

Wastewater treatment specialists Graf UK are calling on architects to help improve ground water quality throughout the UK. Here, David Stagg, the firm’s technical product doyen, explains why they have targeted specifiers.

WE realise that asking architects to become more involved in wastewater treatment is a big one and they might not want to get their hands dirty but they are major influencers when it comes to the two factors that are driving this increasingly contentious issue.

One is that Natural England is increasingly ‘advising’ local authorities to halt the determination of planning applications unless the developments can prove they will be nutrient (nitrogen and phosphate) neutral. High levels of these nutrients, which come partly from wastewater treatment discharges, cause excessive growth of green algae which smothers rare habitats and wildlife.

The other is an update to the General Binding Rules of January 2020. This is a bid by the Environment Agency to reduce the level of sewage pollution in the nation’s watercourses, so is particularly relevant to architects designing properties off the mains sewage network. Under the new rules, anyone with a septic tank discharging into a watercourse must replace it or upgrade the foul water solution.

These General Binding Rules do not apply in Scotland where the regulations governing foul water management are much more stringent.

SEPA (the Scottish Environment Protection Agency) requires wastewater treatment systems for up to 15 people to be registered on a public database so they know what system a property is running and where the effluent discharges to. A system catering for more than 15 people requires a licence and must meet a quality standard determined by SEPA so this can dictate the type of system installed. Here again, is where architects have an influence.

While architects are required to specify solutions for foul water drainage and disposal to Building Regulations Approved Document H, until such time as there is a national governing body for wastewater treatment monitoring, the Environment Agency, SEPA and NRW (Natural Resources Wales) are the individual organisations setting effluent quality standards. These governing bodies have hundreds of regional offices which generally operate independently, so are not set up the monitor this situation.

In addition, approval for a sewage treatment plant is usually via a local authority’s building control department, which could be the most obvious body to take on the registration and monitor of such plants. But as all local authorities operate independently and already have large workloads, that’s an unlikely solution too.

So, without government legislation it would be very difficult to implement a national scheme to deal with this issue, and even then, it would be difficult to implement and monitor. Which is where architects come in.

As well as specifying a sewage treatment system that is appropriate for the level and regularity of use and the ground conditions, architects need to ensure it is installed, commissioned and maintained properly to avoid effluent issues down the line. This isn’t a decision anyone wants to get wrong!

Septic tanks do not require regular servicing but should be monitored and emptied regularly. Sewage treatment plants, which involve mechanical parts, are more complex. These must be emptied at an optimum time (too late or too early can affect effluent quality), which only a competent contractor can advise on and carry out to avoid damaging the internal workings.

There are literally hundreds of thousands of septic tanks and wastewater treatment systems in the UK and unfortunately a high percentage of them are not MoTd correctly. Then you have the rapidly increasing number of new systems being installed potentially adding to the problem. The quality of discharged effluent can vary greatly, with many instances of it not being treated at all.

Many homeowners will not have been advised that sewage treatment plants need to be commissioned after installation and then regularly serviced – annually for a domestic scheme but two or more times a year for larger commercial applications. In addition, systems may have been installed incorrectly by a non-qualified contractor and as a result are unlikely to function efficiently.

While the haphazard monitoring of sewage treatment, in England and Wales at least, looks set to continue for the foreseeable future, it has fallen to some manufacturers to take on more responsibility for the systems they sell.

These manufacturers have become self-monitoring in themselves, working more closely with, and even training and providing technical back-up to the specialist contractors who install, commission, service and maintain their systems.

Ensuring these are installed correctly by competent contractors greatly reduces the potential for sewage treatment plants to develop issues which could affect local water quality, and if they do, for the issue to be nipped in the bud by knowledgeable technical staff and contractors.

The biggest winner is the environment, with improvements to the quality of groundwater throughout the UK. But there are benefits to everyone – the householder, contractor, manufacturer… and architect who influenced the system’s specification.

Gareth Boyd, a director with 2020 Architects in Ireland, who specified a sewage treatment plant over a septic tank for his own self-build, advises: “Don’t always go for the cheapest option as it could be much more expensive in the long run. Speak to your architect and builder for sound advice.”