Habitats Directive Review of Consents
drives abstracted water reduction
Case Study: Cadbury’s
Summary
Source
Application
River Lugg
•
Vacuum pump
system
Constraint
•
•
Habitats
Directive
Review of
Consents
Summer flow
constraint
Response
•
•
•
Some switching to borehole
water
General management
improvements
Proposed new electric pump
system as part of US
$5million investment
Savings
•
•
Abstraction of river
water reduced from
3
over 5,000 m per day
3
to under 4,000 m per
day
Further water savings
of up to 75%, if new
investment proceeds
Company overview
The Cadbury factory at Marlbrook, Herefordshire, processes fresh milk, sugar and cocoa liquor to
produce chocolate ‘crumb’ – the main ingredient in many of Cadbury’s milk chocolate products. The
‘crumb’ is then blended with cocoa butter, refined and turned into milk chocolate at other factories.
For the past 17 years, Cadbury has operated Environmental Management Systems to ensure the
environmental impact of its operations is minimised. More recently, Cadbury has demonstrated its
ongoing commitment to high standards of environmental protection through ‘Purple Goes Green’,
initiative which targets ambitious reductions in the use of resources, including water and energy. In
early 2010, Cadbury became part of the international company Kraft Foods.
Figure 1: Cadbury’s Marlbrook site is situated on the River Lugg
Process overview
Fresh full-cream milk is brought to the Marlbrook site where it is mixed with sugar and then
condensed into a thick liquor through the process of evaporation. The liquor passes through the
system via a series of vacuum pumps and is then mixed with cocoa liquor produced at the Cadbury
plant in Chirk, North Wales. The mixture is cooked and kneaded to the correct consistency before
being dried in large vacuum ovens to produce the final milk chocolate ‘crumb’ (Figure 2).
Figure 2: Illustration of the process at the Marlbrook site.
The production process at Marlbrook is continuous with some seasonal flexibility, for example
production typically increases in the lead up to the Easter and Christmas periods.
The site has 11 process lines (of which 10 are operational and one is offline for cleaning at any one
time) with a capacity to process over 500,000 litres of milk per day, producing 93,000 tonnes of milk
chocolate ‘crumb’ per year. In general, the site operates 5 shifts of 10 operators to maintain
production for 24 hours per day, 365 days per year. The site also has the capacity to store up to
3,000 tonnes of ‘crumb’.
Water use overview
Nearly all of Cadbury’s water is abstracted from river and groundwater sources. Water is drawn from
three boreholes which, along with recovered milk condensate, supply all of the process water used
on site and for vessel cleaning. Water from the River Lugg is used within the vacuum pump system to
create the vacuums required within the cooking and drying vessels and to pump the liquid around
the process. It is used on a ‘once through’ basis and is returned approximately 100m downstream
after passing through a series of on-site cooling lagoons. During winter months, it would be possible
to recirculate water from the cooling lagoons, although during the rest of the year ambient
temperatures make this more difficult. In discussion with local regulators, the view has been that the
trade-off between higher return temperatures and abstraction volumes favours continued
abstraction rather than re-use.
Temperatures are monitored in the cooling ponds to ensure that water is returned at an appropriate
temperature and the chemical properties of the discharges are similarly controlled so that waste
cleaning water is separated from solids and limited chemical treatment is undertaken.
As the milk is evaporated, the water vapour is condensed, collected and re used. This means that
more water is returned to the River Lugg than is abstracted both from groundwater and from the
river, and the product itself contains less water at the end of the process than at the beginning.
Cadbury’s currently has a licence to abstract around 6,500 m3 per day from the River Lugg and a
permit allowing the discharge of 5,500m3 per day back to the river, although a typical daily average
discharge is around 4,500m3 and, in general, the plant is a net contributor of water to the river. The
site generates around 600-750m3 of wastewater per day which is discharged back to river following
dewatering. The resulting sludge is removed from the site as solid waste. Abstractions at the site are
governed by three licences, as set out in Table 1.
Table 1: Summary of abstraction licences at the Marlbrook site.
Consent
Description
19/55/12/827
Boreholes
Maximum
volume per hour
Daily and annual
limits
1+2 combined
3
416 m in any day
19/55/12/53
1
18.18 m
3
2
27.28 m
3
River Lugg
272.8 m
3
3
151,840 m in any
year
3
6,532.6 m per day
3
2,384,399 m per
year
19/55/12/82
Borehole 3
6,000 gallons
52,800 gallons per
day
= 19,272,000
gallons per year
Restated as m
3
27.28 m
3
3
240 m per day
3
87,611 m per year
The costs of abstraction from borehole and river water consist of the pumping costs, which are fuelcost dependent, and the cost of maintaining the abstraction and discharge consents. Abstraction
licensing currently costs around £3,500 per year. Table 2 provides an overview of the site’s
abstraction over the last eight years from the two sources. During the last five years, production at
the site has remained virtually constant at approximately 82,000 tonnes of product.
Table 2: Water consumption at the Marlbrook site.
Trends in water use
Year
Parameter
River water
Total
(Average m /day)
(Average
3
m /day)
(Average
3
m /day)
2002
240
7,497
7,737
2003
84
5,444
5,528
2004
215
5,691
5,906
2005
183
5,744
5,927
2006
200
4,912
5,112
2007
497
4,442
4,939
2008
534
4,135
4,669
2009
563
4,592
5,155
2010
722
3,851
4,573
Average % of
total
7%
93%
100%
Groundwater
3
Constraints on water use
The River Lugg is situated within the River Wye catchment area. According to the Environment
Agency’s Catchment Abstraction Management Strategy, the majority of rivers within the catchment
are of considerable ecological value, providing important and diverse habitats and key breeding
areas for many nationally and internationally important species. As such the international
importance of the catchment has been recognised through the designation of the River Wye and
some of its tributaries as a riverine Special Area of Conservation (SAC) under the European Union
(EU) Habitats Directive (1992).
Further to this, the ‘resource availability status’ for the River Lugg is classed as ‘no available water’
and the Environment Agency (EA) proposes to restrict abstractions by 20% during the summer
months.
The river abstraction limits for Cadbury are, in the most part, suitable for its requirements. The
company has a daily consent (currently set at 6,353m3), which during 2002, 2003 and 2004 was
frequently exceeded. However, measures put in place in 2004/5, combined with increased
abstraction from boreholes, have largely overcome this problem with a decrease in average daily
river water demand to around 4,000m3 and no incidents of exceeding the limit for river abstraction
recorded in 2008, 2009 or 2010 (Figure 3). However, this has led to over abstraction from their
licensed boreholes on site (Figure 3).
Following discussions with the Environment Agency regarding the amendment of two of their
abstraction licences under the Habitats Directive Review of Consents (HD RoC), Cadbury’s set out
their future plans to improve their evaporative cooling system (see below) to ensure that they
remain within their licensed limits. They are also developing a longer term plan to reduce water
usage on site by a minimum of 3% per annum.
Groundwater is abstracted by Cadbury from three boreholes within the same aquifer via on-site
pumping stations (Figure 4). This water is primarily used in the cleaning of vessels and process
equipment.
Figure 4: Pumping station for Borehole 2
Abstraction limits are placed on the three groundwater sources as outlined in Table 1. Currently,
only a small proportion of the company’s water supply is taken from the town’s supply and used for
domestic purposes, including in the canteen and staff facilities.
Exploration of technology
At present, Cadbury deploys a series of vacuum pumps which work by injecting steam into a piston
causing the piston to expand, followed by a jet of cold water causing the steam to condense and the
piston to contract. Water is used for both the steam injection and cooling cycles of the piston’s
action. Borehole water is used to condense the vapour in the evaporators.
The plant currently uses electric pumps with a liquid ring main. The next progressive step would be
to use a ‘dry’ centralised vacuum system. The proposed upgrade would see the replacement of this
system with more modern electric pumps, thereby reducing water demand considerably.
In 2008/9, on-site improvements were undertaken which further reduced surface water extraction
(with an increase in abstraction from groundwater sources), but these were largely either
management and process improvements, or a consequence of changes carried out for production
and efficiency purposes which also improved environmental performance.
Going forward, there are plans for further capital investment in the plant which will both improve
production and reduce surface water abstractions in two phases:
•
Phase 1 will include consolidation of the dairy facility;
•
Phase 2 will include the establishment of a new evaporator unit at a cost of approximately
US $5million. The evaporator unit will recover more water from the milk than is currently
retained and it is anticipated that this will considerably reduce abstracted water use and cut
maintenance costs. Part of this investment will also include the renewal of dated process
equipment which will reduce stoppages, thereby contributing to an overall increase in the
efficiency of the process.
A capital investment of over US $5million is proposed over a number of years, depending on the
availability and release of funds. Within Cadbury, the case for investment is usually based either on
financial benefit or legislative requirements. As it is difficult to achieve financial benefits, owing to
the low cost (including energy costs) of abstracted water, it is often legislative requirements that
drive improvement within the organisation.
The case for investment in the plant is largely tied to the ongoing viability of the plant and the
suitability of its location for continued production. Securing funds at a corporate level involves an
investment appraisal and competition with other demands on corporate capital. Separating out the
costs related to reducing water use from the overall improvements in both production and
environmental quality is not possible. However, given Cadbury’s high public profile, the perception is
that the risks to its reputation and the opportunities associated with good environmental
performance encourage considerably more investment in environmental technologies than might be
warranted by the financial case alone. This has meant that making the case for capital investment at
a corporate level is enhanced by environmental improvements, such that the planned improvements
being proposed for commercial purposes can also incorporate considerable environmental
improvement even where that has an impact on capital costs.
While environmental improvements may not themselves be a direct driver of new investment, they
do appear to influence the design of new plant and capital allocation decisions.