Environmental pollution – is your business watertight?

Business owners and site managers need to ensure that their facilities are protected from water pollution and flooding. How will spill containment systems work in a real-life emergency? Would regulatory authorities be satisfied that containment systems are effective? David Cole from Hydro Consultancy finds out.

Flooding, pollution spills and fires are not far-fetched disasters that are unlikely ever to befall industrial or commercial premises.  They happen all the time. The only acceptable kind of pollution risk is one that a business can demonstrate it has taken adequate measures to protect against. 

Causing environmental water pollution is a risk that many companies may unwittingly be taking every day through failure to contain spills of pollutants including carried in surface water, for example or through.fire fighting water.

Providing evidence of how surface water is discharging to the environment should be on the agenda of any company that is keen to act sustainably.  As well as being environmentally unacceptable, inadequate water pollution containment could be very costly.  

As government funding is cut back, environmental authorities are being forced to relinquish their advisory role and are increasingly enforcing regulations through prosecution.  Even for those operators who are already fully familiar with their responsibilities, a comprehensive review could be both timely and highly advisable

An unexpected pollution incident is likely to land an unprepared operator with significant fines and a substantial bill for environmental remediation.  Insurance cover may not be sufficient to pay for the clean-up costs, in all but the most exceptional circumstances.  In the worst cases, a pollution conviction can even include the option of custodial sentences for company directors.

Notwithstanding a company’s regulatory obligations and noting that in the vast majority of instances the “polluter pays”, the expectations of Corporate Social Responsibility alone (especially for larger companies) make it good practice to demonstrate exemplary environmental compliance.

Tertiary pollution containment

Some sites require defences to be built that capture flood water in above- or below-ground storage systems (for example using bunded areas or underground tanks) from where the polluted water can be safely removed and subsequently disposed of correctly. For most sites though, the conventional practice for managing tertiary pollution containment defence, is to block underground drainage with a containment valve.

Our initial assessment with clients, even on COMAH and EPR sites, has frequently shown that where a containment valve has been retrofitted into below-ground drainage systems, significant pollution risks still remain as a result of valve closure.  Some companies may have little idea of the drainage pathways on their site, and the potential pathways to the environment.

All too often, companies retrofit a valve without actually having any technical evidence to demonstrate how it will hold water pollution safely on site in an emergency.  Even when a valve is well-maintained and working properly, by itself this is not evidence that any polluted surface water will be contained on a site if there is a fire or heavy rainfall.  Will it work effectively alongside bunds or other above and/or below ground flood protection measures?

Without this knowledge, how can companies understand the wide implications of containment system operation when predicting an emergency event, especially when there could also be a source of flow into the below-ground drainage system such as fire water or rainfall?

The drainage system could become overloaded, and the backed-up flows could simply bypass the containment device either by other below-ground flow paths or as overland flood water. Any shortcomings in the containment system could lead to a damaging off-site pollution incident.

Managing flood vulnerability

Under current planning guidelines, the suitability of a new development is assessed using a system that compares flood risk vulnerability against its compatibility with a flood zone.  The National Planning Policy Framework (NPPF) states that for any “installations requiring hazardous substances consent” such as COMAH and EPR sites, their vulnerability classification would be “highly vulnerable”.

This would place planning restrictions on such development on the grounds of flood risk in two of the three “Flood Zone” classifications.  But this applies only to new developments and many existing sites are unlikely to have been built according to these guidelines.

So when considering existing “highly vulnerable” sites, it’s a fair assumption that a great many of them are located in a flood zone that is not appropriate to their vulnerability, with the residual flood risks largely not understood.

Even if a site is not directly adjacent to a watercourse, the flood risks may still be significant.  Most people are familiar with high-profile flooding events from rivers as a result of prolonged periods of extreme rainfall.  However, there are many other sources of flood risk that are easily overlooked, but can have just as serious implications.  These sources include surface water, tidal, groundwater, infrastructure failure, such as a dam or canal breach and fire water. 

COMAH compliance

The introduction of the revised COMAH regulations on June 1st 2015 has provided a timely opportunity for regulated sites to fully review their environmental risks and ensure both their business and the surrounding environment are fully protected.

Pollution containment is particularly critical for sites operating under the Control of Major Accidents and Hazards (COMAH) 2015 or Environmental Permitting (England and Wales) Regulations (EPR) 2010.  It should also be integral to any compliant Environmental Management System (EMS) – or for those companies working to IS0 14001. Sites that store or use hazardous or polluting substances in particular, need to take steps to ensure they do not escape into the environment on or off a site. 

A robust flood risk assessment provided by suitably-qualified experts will identify all sources of flood risk, along with potential flow paths into and out of a site.  A Hazard and Operability (HAZOP) study may also be an appropriate methodology to support an evidence-based understanding of the combined water pollution and flood risks, especially for COMAH or EPR sites.

As part of this process, using hydraulic modelling can be invaluable.  It can accurately map the surface water pathways on and off-site as well as assessing and validating the effectiveness of the drainage system design.

Hydro Consultancy has developed this 2D modelling technique, a pioneering approach that requires a mix of flood risk and pollution containment expertise.  It can provide an effective method to test the efficiency of containment systems – and provide reliable evidence for regulators and Environmental Management System documentation.

Seeking expert help to reassess and provide evidence of a site’s compliance with water pollution containment is, perhaps, more important than ever before.  

David Cole is water pollution manager at Hydro Consultancy.

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