It's business as normal - or is it?

Uncovering hidden Mogden costs in trade effluent discharge

Commercial and industrial waste in the UK now amounts to a whopping 48m tonnes per year, according to recent research by the Department for Environment, Food and Rural Affairs (DEFRA). More specifically, it's surprising that many businesses continue to blindly pay Mogden charges on every cubic metre of trade effluent they discharge without making an effort to reduce the cost. Here the Wastewater Innovation Platform of global water, energy and maintenance solutions provider, NCH, looks at how industrial users can reduce their charges.

As consumers how many of us give a second thought to the things we throw away? Only 44 per cent of the 26m tonnes of household waste that was thrown out last year was recycled. Despite this, we're still on target to meet the EU recycling target of 50 per cent by 2020. This is impressive, given that many of us still don't take recycling seriously. However, can you imagine if local authorities started charging households for landfill waste? It goes without saying that we'd get our act together fast.

However, in most industrial applications, it is the norm to pay for effluent discharged. From food and beverage applications to wastewater treatment, companies can improve the efficiency of their wastewater handling and save money.

The concentration of effluent is affected by its overall volume and load characteristics. In the UK the Mogden formula is used by utility providers to calculate charges per cubic metre of discharge received.

The Mogden formula takes into account variables including the volume, amount of chemical oxygen demand (COD) and suspended solids (SS) among other variables, present in the effluent and customers are obliged to comply with legal limits.

The consequences

Wastewater is produced in such high volumes, even concentrations with 0.1 per cent of suspended solids, which would otherwise be considered harmless, can bring about a detrimental impact on the environment over time.

If trade effluent, discharged into public sewers, finds its way to receiving waters such as oceans, rivers, streams and other waterways, it can cause the chronic contamination of organic matter, which can result in oxygen depletion, fish being killed, eutrophication (nutrient over-enrichment), bad odours and it can potentially create a health risk to the general public in the form of water-borne pathogens. As a result, industrial businesses that discharge effluent into rivers are exposing themselves to a failure to meet regulatory compliance objectives, which can result in prosecution.

Under the provisions of the Water Resources Act 1991 in England and Wales, the Control of Pollution Act 1974 (as amended) in Scotland and the Water Act 1972 in Northern Ireland, consent from the relevant agency - normally the Environment Agency in the UK - is required for any discharge of sewage effluent into controlled waters.

Even when effluent isn't directly discharged to rivers, any industrial businesses that discharge to sewers, will face financial consequences in the form of charges, court imposed fines for non compliance and raised internal operating costs.

Business as normal

Having become accustomed to paying charges over many years, most companies turn a blind eye to their waste water charges, considering them a necessary evil and just another part of doing business as normal.

However, this is not the case. Industrial customers have several options when it comes to managing their wastewater. Most small plants will fit a basic retention tank in combination with a settling and pH correction tank before discharging effluent for the utility provider to process in their own water treatment works - incurring the relevant charges.

To reduce the impact of Mogden charges, larger plants may invest in on-site pre-treatment equipment, which reduces the concentration. However, there's always more that larger plants can do, using bio-augmentation for example, to improve wastewater treatment.

FOG off

Effluent is made up of various carbohydrates and proteins as well as animal, plant and cooking fats, oils and greases (FOGs). Enzymes and surfactants are chemicals that have been previously used to liquefy the effluent, which causes problems in wastewater treatment plants, drainage pipes and sewers.

Here, it can cause waste to congeal, often into fatbergs - enormous balls of fat and grease - blocking pipes and requiring extensive manual removal and infrastructure repair. This is one of the main reasons why these chemicals are not favoured by many local authorities.

To overcome this problem, and provide a third option for industrial customers, NCH's Wastewater Innovation Platform has developed a patented system called BioAmp, consisting of two parts. The first is a range of automated, computer controlled delivery systems and the second is FreeFlow, a unique biological agent available in either tablet or liquid form, which contains up to 12 species of bacteria designed to biologically break down complex waste streams.

Biological treatment alleviates Mogden charges and problems larger plants face with extensive manual labour, foul odours, FOG blockages and organic waste that clogs drain lines and grease traps. Each day, BioAmp doses large quantities of live, food-safe active bacteria into the system. The active bacteria immediately work to reduce sludge volume by up to 50 per cent. This reduces operating costs further by eliminating the need to pump out grease and sludge in lift stations and grease traps.

Smaller plants can use the same system to introduce an affordable on-site wastewater treatment solution and reduce the costlier COD and SS variables of the Mogden charge and so reduce the risk of non-compliance.

Eyes open

At first glance wastewater charges are not an obvious area of cost savings. However, in an increasingly competitive and highly regulated sector, it is time industrial users opened their eyes to the cost savings that can be achieved, along with the resulting environmental benefits.