Water
We remain ahead of our 2020 target to reduce mains water use by 25 per cent based on 2010 figures and have met our 10 per cent reduction target in total water use in concrete.
The use of mains water fell to its lowest recorded level of 17.5 litres per tonne of product, while absolute mains water use also fell. This was due principally to a reduction of nearly a quarter in the cement business line, achieved through a concerted drive to identify and repair leaks and greater use of recycled water. We have also installed smart meters at 25 of our biggest water-using sites, allowing better management.
The use of controlled water also fell both on an absolute and per tonne basis.
A new closed water system at Purfleet Regen plant in Essex has reduced mains water use by 93 per cent. The plant’s ball mill was previously fitted with an open circuit water cooling system to reduce oil temperatures during production. The system used mains water to fill a buffer tank which was then pumped through the oil cooling jacket with the warm water diverted straight to the drains.
The new system uses a 1,000 litre buffer tank and an adiabatic cooler to control the water temperature. The water is pumped from the buffer tank around the mill but rather than dumped to drain it returns to the tank via the cooler, allowing the water to be recycled back around the system.
As a result, water use has dropped from over 2,500 cubic metres a month to just to 235.
-
Water consumption
2010 (baseline)
2016
2017
2018
Mains water consumption – Litres per tonne
26.03
20.86
17.95
17.51 Mains water consumption – megalitres
890.0
855.6
727.4
724.8 Total water consumption – megalitres
9,384.3
8,581.2
8,135.3
7,778.3 Total water consumption – litres per tonne
274.44
209.22
200.76
187.90 Concrete total water consumption – litres per tonne
85.99
82.58
77.44
77.43 When normalised for production changes at business line level, the 2018 performance is 18.4 litres/tonne against a 2010 baseline of 24.7 litres /tonne, showing a reduction of 25.4%