Continuous improvement drives down
abstracted water use
Case Study: Sunlight Textiles Services
Summary
Source
Application
Borehole
•
•
Garment
washing.
Ironing
steam.
Constraint
•
•
•
•
•
SSSI Designation.
SAC Candidate.
Reduced
abstraction limit.
Corporate CSR.
Previous
prosecution for
over-abstraction
Response
Re-design of
Continuous Batch
Washer (CBW).
Implementation of
maintenance schedule
on CBW.
•
Automated top-up shut
off on CBW.
Investment in water
efficient washer
extractor.
•
Leak detection
activities.
Chemical additives to
reduce water use.
•
•
Condensate return.
•
•
Not considered.
•
•
•
•
•
•
Mains
•
•
Domestic
sanitation.
Canteen.
•
•
None related to
the application.
Cost.
Savings
•
•
•
Reduced water use
3
(260m per year).
Reduced downtime.
Reduced water use
(26 litres/kg to
12litres/kg).
Reduced energy use.
Reduced water use.
Reduced water use
(18 litres/kg to 6
litres/kg).
Reduced water use.
Reduced steam and
energy. More water
available for re-use.
Reduced water and
energy use.
Company overview
Sunlight Textile Services is a large-scale commercial laundry providing services to a range of hotel
groups, restaurants and manufacturing companies. It is based in Fakenham, Norfolk and covers an
area of 6,000 square miles across the south east of England. Until December 2005, the laundry was
owned and operated independently, but is now part of the Sunlight Textile Services division of the
Berendsen Group.
Essentially, the Fakenham site has three distinct business operations:
• Linen - including sheets and duvets which are often rented out to hotels.
• Industrial - including workwear for garages and factories.
• High Care - including overalls from the food and drink manufacturing industry. The High Care
operation is subject to strict food-hygiene standards and is kept separate from the rest of the
site.
In summary, around 250,000 pieces of linen and 125,000 pieces of other commercial pieces,
including some Industrial and High Care items, are laundered each week.
Each of the business operations has high and low seasons, which means the total workload is fairly
constant throughout the year. For example, in the run up to Christmas, there is a noticeable increase
in High Care items as the food and drink industry increases production, but the weekly throughput in
the Linen operation is only about 120,000 items - half of that processed during the summer due to
the hotel sector’s high season. To meet demand during these busy periods, the site can increase the
hours available to staff and hire agency staff when required.
As part of achieving the Carbon Trust Standard, each of the sites in the Berendsen Group monitors
its electricity, gas and water consumption, and has reduction targets to meet. Progress towards
achieving these targets is reported at group level on a monthly basis. A league table of each site’s
performance is constructed based on the cost of utilities per piece (e.g. Water Cost pence/piece).
This has created healthy competition between the sites and Fakenham is currently leading the way.
The main driver for the Fakenham site is built around a philosophy of continuous environmental
improvement, which has been developed following a prosecution in 2008 for over abstraction of
water from the River Wensum. Employees recognise the value of water as a resource and are fully
aware that every cubic metre (m3) of water used includes the embedded cost of energy, softening
and wastewater treatment as well as the cost of the water itself. They fully appreciate that any
water saving contributes directly to the company’s bottom line.
Led by General Manager, David Lott, the laundry has reduced its water use by over 50% compared to
2007 volumes with only a 10% reduction in overall throughput. Sunlight is so proud of its
achievements that it supports its machinery suppliers by allowing competitors to visit the site and
view a new water efficient washing machine in use at the site.
Process overview
Linen from hotels and restaurants enters the site and is segregated into starch and non-starch items.
The items are then washed in either of the two continuous batch washers (CBW). This produces
around 50kg of clean items every 2 - 3 minutes depending on the machine used. During the final
stage of the wash cycle, water is squeezed from the washing with a water ‘cushion’ under the
garments for protection; this water then forms the first stage of the wash cycle in a countercurrent
operation.
Industrial workwear is washed in one of the five washer extractors. Figure 1 shows the latest and
most efficient of these machines – the Smartex 120 Miracle.
Figure 1 Smartex 120 Miracle water efficient washer
High Care garments are processed in the site’s Milnor CBW (see Figure 2). As with the linen process,
the ‘work’ passes through a number of separate stages and the water flows in the opposite direction
as a countercurrent operation. Water is removed from the system via a centrifugal extractor and is
recycled back to the first stage of the wash cycle. After washing, the items are passed through a
tunnel Finishers to remove wrinkles before being fed through large ‘Lavatec’ steam irons. The
finished garments and are then folded and baled for dispatch.
Figure 2 Milner CBW with countercurrent rinsing
Water use overview
The Fakenham site is now one of the most efficient laundries in the Sunlight Group. The site uses
between 290m3 and 310m3 of water per day (around 80,000m3 annually). Virtually all of this is
sourced from the site’s borehole.
In 2003, Sunlight had a new abstraction licence issued with a substantial increase in annual quantity
to reflect existing commitments and perceived future demand. The new licence more than doubled
the annual quantity of the pre-existing licence (and was almost 17 times that of the original licence).
However, the importance of the River Wensum for its wildlife had been recognised in its designation
as a Site of Special Scientific Interest (SSSI) and as a candidate Special Area of Conservation (SAC)
under the Habitats Directive. As part of the Review of Consents process, a time-limit of 3 years was
initially applied to the licence, pending the outcome of the review (this time-limit was ultimately
extended to 7 years).
In 2010, the review concluded that the higher licensed quantity was likely to cause damage to the
River Wensum, and needed to be reduced. The quantity licensed prior to 2003 was considered
acceptable, provided that all other licence reductions proposed by the ‘site action plan’ also went
ahead. Fakenham Laundry was faced with a 41% cut in their existing annual licensed quantity.
Sunlight was given advanced notice of this, and since the prosecution in 2008 for exceeding the
625m3 daily abstraction limit, the company has worked closely with the Environment Agency to
achieve a voluntary reduction in its water use (initially 50m3/day), as well as incremental reductions
allowing adequate time to implement the water minimisation measures required to meet this new
baseline quantity. Table 1 outlines the site’s abstraction schedule through to, and beyond, April
2012.
Table 1 Borehole abstraction schedule
Date to
Mar 2011
Sept 2011
Mar 2012
From Apr 2012
Imposed daily
abstraction limit
629m3
500m3
450m3
324m3
Sunlight is licensed to abstract water over a 19-hour period each day and for not more than 6 days
continuously. These conditions determine the laundry shift patterns and working hours. Additionally,
the site has a licence to use up to a maximum of 199m3 per day from the mains supply if required.
However, this option is rarely (less than once a year) used for process purposes - typically only as a
result of a borehole pump failure. The site takes around 4m3 of mains water per week for domestic
use only, specifically the toilets and canteen.
Water entering the plant is softened prior to being heated in the gas boiler to create steam or being
used as cold water in the process. It is thought that this softening process adds around 19p per m3
(1). Cold water is first put into the machines and steam is then injected to bring the temperature of
the washing machine up to an appropriate level. A system is in place that closes the steam valve
when the required temperature is reached.
Figure 3 shows how water use at the laundry has decreased over the last four years. Currently,
annual water costs are around £1,600, which includes the fixed abstraction licence fee.
1
Provided by the manufacturer, this includes salts, plant wear and maintenance
Figure 3 On-site water consumption (2006 to 2011)
Figure 4 shows the throughput for the site over the last five years. In 2008, work was moved off site
as a ‘quick-fix’ solution to Sunlight’s over-abstraction issues while it developed a long-term strategy.
Since then, the number of pieces being laundered at the site has steadily increased to 2007 levels. In
the last 2 years, productivity at the site has also increased; improving from 7.5l per piece in 2009 to
4.2l per piece in 2011 with associated water costs of around 0.02p per piece, down from 0.15p per
piece in 2010 and by far the lowest in the group.
Figure 4 Throughput at the Fakenham site (2006 to 2011)
Constraints on water use
The River Wensum is currently considered ‘over-abstracted’ by the Environment Agency. The
Environment Agency has approached the larger water users in the catchment to reduce the amount
they draw from the local environment. Since 2008, when it was set at a maximum of 625m3 per day,
Sunlight’s borehole licence limit has been reduced annually. Following negotiations with the
Environment Agency, as of March 2012 the limit will be fixed at 324m3 per day. As a result, Sunlight
has had to re-examine all of its processes and ensure they are working as efficiently as possible.
Currently, the site is using between 290m3 and 310m3 per day depending on the season.
Sunlight has implemented a borehole control system that ensures it does not over abstract from its
water source. Each of the borehole pumps is fitted with a sub-meter, which in turn feeds into the
main borehole meter. This meter is monitored by a data logger outputting to a PC, which can shut
down the pumps if the company’s daily abstraction limit is reached. An overview of this process is
shown in Figure 5.
Figure 5 Borehole pump control system
Post-treatment/disposal
Around 90% of the site’s water leaves as effluent discharged to the local sewer. Currently, this is
being processed by the local treatment plant and Sunlight has a trade effluent licence governing this
discharge. In an effort to reduce the environmental impacts of its effluent, Sunlight liaised with
Anglian Water to identify suitable phosphate-free detergents and, as such, has built up a good
relationship with its water treatment supplier. Effluent costs the site around £1.36 per m3 (about
£98,000 annually).
Water abstraction reduction measures
Since 2008, the Fakenham site has reduced its abstracted water use by around 50% by implementing
a culture of continuous improvement. In addition to the water savings, the site has benefited from a
reduction in associated costs (e.g. heating, pumping and softening the water). The measures
introduced to achieve this include:
•
Improving the efficiency of the CBW. The CBW was set up in such a way that compressed air
was used to keep the wash water in the CBW wash compartments and springs were used to
send the water to drain. Any failure in the compressed-air unit resulted in water being
washed to drain prematurely. The water tank feeding the washer is located in the roof
structure. The height of the tank created additional pressure in the system, which often
caused a seal failure at weekends. Therefore, the mechanism was redesigned so that the
springs kept the water in and compressed air was used to send the water to drain. In
addition to the downtime associated with refilling the washer, weekly water use was
reduced by around 5m3 to 6m3 (260m3 to 312m3 annually).
By implementing a regular maintenance schedule for the CBW, the machine’s water usage
was reduced from, 26 litres per kg to 12 litres per kg. The capital outlay on replacement
chains, sprockets, seals and valves was around £60,000. The company was able to secure the
investment by demonstrating the associated short and long-term benefits of undertaking
this work, such as reduced water, energy and chemical use and also highlighting the
consequences of not taking action.
Water from the last stage of the cycle is used in the first stage of the wash cycle. However,
when there was not enough water, a manual valve could be opened that would feed in more
borehole water. This was often left on by operators, which caused water to run straight to
drain. A system that fills the tank for 10 minutes before automatically switching off has now
been installed.
•
Optimising wash processes. Driven by the requirement to reduce water use, the site
invested in a new, more efficient, washer extractor (the 120kg Smartex 120 Miracle). This
replaces a machine that was coming to the end of its life and is used to clean highly soiled
items. Following further optimisation of the wash cycle, water use has been reduced from 18
litres per kg to 6 litres per kg. The decision to invest in the Smartex machine was primarily
driven by the requirement to reduce water use to meet the abstraction licence target,
despite costing £10,000 more than a standard machine the company felt that the additional
expenditure would help them remain complaint.
•
Leak-detection activities. To listen for leaks, engineers would come in at the weekends
when plant machinery was shut down. As a result, a number of leaks were identified. The
machines were then fitted with butterfly valves that automatically closed off the water
supply to the machines at the weekend. This has cut down on the pressure build-up inside
the machines and has reduced the chances of further leaks.
•
Chemical additives. A ‘Sanoxy’ dosing system, which costs about £8,000 and can save
around 4l of water per kg of laundry processed, is installed on one of the company’s Lavatec
steam-iron machines. Sunlight is also going to install the system on its linen CBW machine.
This has the added benefit of making more water available for re-use.
•
Condensate return. Due to its embedded energy content the hot condensate from the
process is recovered. To ensure it remains efficient the condensate traps are changed on a
4-weekly basis as part of the regular maintenance schedule at a cost of £120. The energy
savings from this ensure the payback period is short.
As a result of the overall reductions in water use on site, the company no longer requires as much
steam; as such, the oil-fuelled boiler that was previously used for 80 hours per week is no longer
required. It is now run for just 30 minutes a week to ensure it still functions correctly, and the gas
boiler provides all of the required steam. As a consequence, the boiler operation is the most efficient
in the group, operating at only 1.53p per piece.
Future considerations
A supplier of water reclamation equipment has recently completed a trial at the site of a system that
uses flocculants to remove impurities in the water. A medium-sized plant costs around £330,000.
While the company is satisfied that it can meet the requirements of its abstraction licence, this may
offer an alternative that will allow them to keep up with demand while not over-abstracting from
the water source should further pressures be placed on their water supply.
Ceramic and reverse osmosis treatments, which will cost upwards of £600,000, were also
considered. However, two sites in the group have already installed similar systems and they have
proved to be unreliable and costly to maintain. When operational, a 90% effluent recovery is
achievable.
Summary
Sunlight Fakenham has demonstrated that continuous environmental improvement is at the heart of
its operations. By implementing small changes to its processes, thinking sustainably, carrying out
regular maintenance and making staff aware of the
importance of water resources, Sunlight has achieved a
50% saving in its water use, while throughput has only
reduced by 7.5%.All of this was undertaken with minimal
capital investment and the company is now benefiting from
increased competitiveness, reduced water resource risk,
compliance with the conditions of their abstraction licence
and associated cost savings.