December 2008

Treating distillery waste water Patrick Hawes of ARM Ltd a leading supplier of natural wastewater treatment systems has been working with brewers and distillers on the applications of reed bed technology for treating waste water.

The challenge

The production of beverages is a water intensive process and, as a result, generates

large volumes of polluted water. A study by the International Centre for Brewing and

Distilling at Heriot-Watt University in Edinburgh suggests that the UK brewing

industry uses an estimated 34 million m of water annually, over 70% of which is

discharged as trade effluent.

For the distilling process, it is estimated that up to 20 litres of wastewater is generated

for each litre of ethanol manufactured.

Whisky production generates an effluent containing a significant amount of copper that

is scoured from the copper stills during the distillation process. No soluble copper is

found in the alcohol that goes to produce the whisky, but there is a quantifiable amount

left in the pot ale (residue left in the wash still after distillation) and spent lees (residue left in the spirit still).

Typically, spent lees can contain copper at concentrations of 25 to 40 mg per litre. Whenever there is a discharge to a watercourse, the soluble copper levels in the water

are consented by the regulator.

Organic components in brewery effluent are more easily biodegradable as these mainly

consist of sugars, soluble starch, ethanol, fatty acids, and so on. However, it is still

necessary to treat the wastewater before it is released into the environment.

Many distilleries are located in remote areas and lack access to mains drainage. Where

space permits, they may have their own effluent treatment plant on site and may also

tanker in effluents from surrounding distilleries for treatment. With increasing

discharge consents, many effluent plants may require additional treatment systems in

order to achieve these tighter consents.

The use of wetlands to treat dirty water is not a new idea. In fact, records indicate their

use for this purpose 2,000 years ago in China. It is, however, only relatively recently

that their application has been considered more scientifically. Work began back in the

1960s in Germany to better understand and formalise these systems to treat effluent to a

specific standard.

ARM constructed their first horizontal reed bed system to trial the suitability of the

technology to treat agricultural effluents in 1985. After years of research and

development, including affiliations with several universities, they now use reed bed

treatment systems for a wide range of effluents and industries.

Reed beds can be designed to remove contaminants such as organic waste,

hydrocarbons and heavy metals. The type of reed bed employed is engineered

specifically to the type of waste water and individual requirements of the particular

industry or challenge.

The principles of reed bed design are, however, similar regardless of the specific type

of treatment system employed horizontal flow, vertical flow. In essence, the wastewater is filtered through a gravel matrix in which the reeds are planted. Bacteria

thrive in the matrix and break down the contaminants.

Reed bed treatment systems are a highly flexible, environmentally-friendly, low

maintenance treatment solution to wastewater challenges.

Over the last 30 years, the technology has been proven through research and

development as well as the extensive use of engineered systems within industry and

municipal treatment.

They have been used successfully at breweries and distilleries throughout the world,

from India to the Caribbean and here in the UK to treat wastewater in a cost-

comparable and sustainable way.

Case study: The solution a distillery in Dufftown, Scotland

A distillery, belonging to one of the worlds leading premium drinks companies, has turned to reed bed treatment systems to remove copper traces from the effluent

produced. The distillery is located in the Dufftown region of Scotland which has the largest concentration of distilleries in such a small area anywhere in the world.

We have installed a horizontal, subsurface-flow reed bed at this site to reduce soluble

copper concentrations in the water discharge to the consented requirement of 0.5 mg

per litre.

Treating up to 650 m of wastewater per day, the reed beds are used as a final treatment

stage to 'polish' the effluent after it has been treated in an onsite bio-plant. Chosen for

their tolerance to metals and ability to remove copper from wastewater, the reed beds

are planted with Typha latifolia.

Our experiences at this distillery led to us presenting a paper at the 11th annual

International Conference on Wetland Systems for Pollution Control in India on copper

removal by reed beds for the treatment of distillery wastewater in November 2008.

- 733 words -

Kinetic Communications 0121 212 6250