Abstracting water in an environmentally sensitive location

Meeting a successful Welsh creamery’s need for new, dependable water supplies required a focused team effort

ACC background
The ACC Creamery in Llangadog, Carmarthenshire is part of ACC Milk, owned by the Co-operative Group. It produces a full range of cheese products, from bulk commodity to retail packs. It is now one of only two milk canners in the UK, producing 115 million cans and 12 million cartons annually, and its Welsh range includes rice pudding and dairy custard.

Butter—including an award-winning Welsh Salted Butter—milk powders and UHT products are also key products.

It originally opened in 1957 as a milk receiving unit, to despatch to London bottling plants by road and rail. The manufacture of milk products began in 1961, firstly with butter and powder, and later with canned goods packing.

The creamery is a success story, and there has been a multimillion pound investment over recent years on new plant and equipment and on improving existing equipment. The most recent installations include a high-speed canned goods packing line, new spray drier, reverse osmosis plant and process plant for the preparation of blended milks for canned and UHT products.

Growth continues—2002 saw a major co-packing contract with food giant Nestle, packing well-known brands Carnation, Simply Double, Tip Top, Ideal and Libby’s Rice Pudding.

Water requirement
Water is used for cooling, processing and washing. However, growth had put stress on the creamery’s water supplies, which were being taken from the nearby Towy river.

After abstraction it is treated to ensure its safety, and finally returned after use in a clean state to the river, via ACC’s effluent plant.

Although their need is only to ‘borrow’ water—they actually return more of the precious fluid to the river than they abstract, thanks to the milk evaporation process—the supply had become unreliable: Taken downstream of a bridge, there have been constant problems with shale and silt build-up.

A plentiful and stable supply of water was essential to ACC’s continued success, so the decision was made to look for alternative sources.

By accessing groundwater from the gravel aquifer, improved water quality was expected, with less sensitivity to river bed movements and low river levels.

Environmental matters
Ian Douglas, ACC’s engineering manager, was responsible for coordinating the water project, and comments: ‘The Co-operative movement takes its environmental responsibilities very seriously. Beyond any legal requirements, in looking at new sources we are concerned to minimise impact.’

The creamery is located in a rural area. The River Towy’s source is in the Cambrian mountains, and it enters the sea at Carmarthen town. The river itself is a Site of Special Scientific Interest (SSSI). This is one of Wales’s premier salmon rivers, with a wide diversity of wildlife, flora and fauna. So guarding its purity is essential.

The Environment Agency (EA) were consulted, and their requirements clearly understood, and they have been instrumental in guiding ACC’s quest for water

A fluvial study was conducted in 2001 by Fluvio, of the Institute of Geography and Earth sciences at The University of Wales in Aberystwyth, under the direction of Dr Tom Coulthard.

Hydrogeology
Independent hydrogeologist Rebecca Exley was called in to assess the potential for groundwater abstraction. She says: ‘The valley is an infill of glacial and river deposits and we were looking for water from the fluvioglacial gravel level.’

Information was that the bedrock—strata of grits, sandstone, sandy mudstones and grey shale—is highly disturbed, with rapid changes of lithography over small areas.

Lack of data meant drilling test boreholes to assess likely flow rates, and this work was conducted in 2001.

Rebecca Exley’s detailed report suggested that groundwater abstraction of up to 4000 cubic metres a day would be feasible beneath the creamery site, although the EA licence creates a limit of 2728 from the river.

It was decided to sink five production boreholes, with five observation boreholes drilled to monitor the area of effect. These are all to the base of the gravel aquifer, between 19 and 26 metres deep, and 50 metres apart: at this distance they will not interfere with each other.

Drilling for water
The company selected to drill the boreholes was Presteigne-based WB&AD Morgan Limited. Says their managing director Brian Morgan: ‘We have built a good reputation for operating in environmentally sensitive situations, and for us this was an interesting project.’

Final boreholes were sunk in 2003, and 380mm diameter holes drilled to create a 250mm final size.

Morgan was also responsible for pumps, controls and headworks. The headworks were raised 2 metres above the flood plain.

As the bands of gravel were thin, a ‘304’ stainless steel wedge-wire screen and casing were used, rather than the more usual PVC style. The reason for this is to improve hydraulic efficiency using better entrance velocity. After installation, a vacuum cleanup removed clay from the area of the screens, to ensure clear flow.

Although the hydrogeologist pointed out that drilling in an unconsolidated aquifer is risky in terms of borehole failure, and that success could not be guaranteed, all the boreholes worked.

Trials commence
With the holes drilled, trials commenced in August 2003, and water is presently being pumped. This has enabled monitoring during a dry summer, and into winter. ACC are assessing abstraction capacity and water quality. Initial assessments are being made at the rate of 155 cubic metres per hour.

The creamery is presently working with Fluvio to assess any impact on the Towy, and the EA are also monitoring the situation.

Presently pumping forms the basis of a 60 day trial: water levels of the three rivers in the vicinity are being measured, together with daily rainfall.

But the indications are that ACC has a new, secure source of water that will let the creamery live in harmony with the environment.

Comments ACC’s Ian Douglas: ‘Rather surprisingly, water coming from the boreholes is harder than the river water. But our need for treatment is lower, as we are not having to cope with the bacterial levels found in river water. This brings an added environmental bonus, in that we are able to reduce chlorination levels.’