Coca-Cola develops a taste for water ultrafiltration
20 Nov 2007
Global soft drinks giant Coca-Cola has made ultrafiltration (UF) a minimum standard for water treatment at all new facilities and facility upgrades worldwide. The decision follows the success of a pioneering project for the technology at its flagship UK plant in Wakefield, Yorkshire.
Wakefield is the largest of six major bottling plants operated by Coke-Cola Enterprises (CCE) in the UK. The facility houses 10 production lines and has a capacity of 3,000 330-ml cans/minute, 500 three-litre bottles a minute, and, claims the company, the world's fastest two-litre filling line. The Yorkshire site is also CCE's regional distribution depot for the UK, storing 25,000 pallets and handling up to 250 lorry movements a day.
Two years ago, CCE moved to upgrade its water treatment facility towards a target of increasing its capacity to supply the production/bottling plant from 260m3/hr to 400 m3/hr. The £1.3-milllion project was led by Severn Trent Services as the main process contractor, with Dutch group Norit awarded a £300,000 contract to design, manufacture and install a membrane filtration and wash water recovery system.
As well as the higher capacity, the new system had to comply with the Coca-Cola 'red book' for water treatment that applies to the raw water coming into its factories worldwide, said Alan Ellis, UK project engineering manager for CCE. This, he noted, specifies exacting standards for water quality, including a turbidity of less than 0.2 and total chlorine content below 0.05 mg/litre.
The Wakefield plant uses mains-fed water from a Yorkshire Water surface water treatment plant, which is relatively high in organics at peak times and rainfall periods. The previous water treatment system, which was built in 1989, was based on lime coagulation and sand filtration, with carbon filtration for dechlorination and an ion exchange unit for organics scavenging.
This first-phase treatment at the Yorkshire site is required to raise the quality of incoming water to a semi-treated stage, before a phase II system of deaeration, cartridge filtration and UV sterilisation prior to bottling.
The move to adopt membrane filtration process went slightly outside the Coca-Cola rulebook, according to Dave Lumb, process team leader at the Yorkshire facility. The decision, he said, was taken on the basis that it offered significant operating benefits over the previous plant, which ran an approximate 90% wastewater recovery system and generated 700 m3/day of waste.
With the new system, incoming water from the mains is stored in two 800m3 storage tanks from where it is pumped to four activated carbon tanks containing a total of 66m3 of filter medium. It then passes through an ion exchange system to remove organics. The organic scavenging process is required as organic content is a key quality parameter of CCE's product make-up water.
"Although organic levels in the raw water supply are generally low, they are subject to seasonal fluctuations," Lumb explained. "We tend to see lower levels in the summer months and an increase in autumn and winter. It is at these times that the scavenger comes into its own and allows us to be confident that water used to create our products is effectively treated."
Feed water from the organics scavengers passes to the ultra filtration system; four parallel streams each with a normal capacity of 100m3/hr and a peak capacity of 133 m3/hr (see panel p24).
Control of the water treatment plant is integrated into the SCADA-based systems for the production lines. Information on how the plant is running is shown on a single screen along with information on parameters such as flow, pH, temperature, pressures, turbidity and chlorine levels at all stages of the process.
Permeate from the UF system passes through the semi-treated water tanks that supply the feedwater stock to the final stage of the treatment prior to the bottling lines. To meet Coca Cola's current rules the system has a 20-micron polishing filter after the water treatment plant, though this requirement may change with the use of UF filtration in the phase I treatment.
CCE runs the carbon filter for 96 hours between each backwash, the organic scavengers for 376 hours, while each of the Norit skids are operated three hours between each backwash. "The backwash is based on double forward flow, so we backwash it at typically 240-250 m3 through the Norit skid over a 30-second cycle," explained Lumb. Backwash water from the UF skids goes into a recycle tank and then through a Norit skid to clean it again in a continuous cycle.
The new water treatment plant went into operation in July 2006, with the previous facility decommissioned after six months of safe operation. The system, stated Ellis, is delivering a 50% increase in capacity with a wastewater flow of just 20-30m3/day — a 30-fold reduction in wastewater generated at the plant.
The plant has been recorded as 97.8% efficient, whereas the previous system was only reaching near to 95%, said Lumb, who added: "This is important. When you are dealing with 400 m3/hour, you could be throwing a lot of water away over the year." Water composition, he added, is much improved in that there is no coagulant there and disposal costs are reduced.
Another gain is that the new facility has a 50% lower footprint due to the use of membranes and the elimination of the membrane coagulation stage, which has freed-up space for a new juice production line.
The new water treatment facility is also designed for ease of maintenance, with all the pipework and valves located at low level, and even the light fittings in the roof space can be lowered down to ground level at the flick of a switch in the corner of the building.
"The plant was designed with the people who operate it in mind," explained Alan Ellis. "We looked at the activities that people have to do on the water treatment plant today and then took the process back to eliminate some of that work. We try to keep to this philosophy, building around the people who operate the plant as well as what the business needs, rather than just working to the lowest possible cost."
The UF systems at Wakefield
The Norit system comprises four skids with capacity to process 700 m3/day. The parallel units each house 24 Norit Ex-Flow membrane elements - a hollow fibre system based on an 0.8mm hollow fibre. This offers filtering down to the ultrafiltration range, which offers protection from bacteria and from viruses, including cryptosporidium.
The skids each comprise six 316 SS tubular pressure vessels, housing 24 SXL225 Norit X-Flow membrane cartridges, which are 1.5m long and 200mm in diameter. Each cartridge contains over 10,000 polymeric hollow fibre filters, 0.8mm in diameter with a filtration pore size of only 0.03 microns and an effective filtration surface area of 40m2. Each membrane is automatically tested on a daily basis and can be isolated and repaired without affecting the running of the plant.
Wakefield is the largest of six major bottling plants operated by Coke-Cola Enterprises (CCE) in the UK. The facility houses 10 production lines and has a capacity of 3,000 330-ml cans/minute, 500 three-litre bottles a minute, and, claims the company, the world's fastest two-litre filling line. The Yorkshire site is also CCE's regional distribution depot for the UK, storing 25,000 pallets and handling up to 250 lorry movements a day.
Two years ago, CCE moved to upgrade its water treatment facility towards a target of increasing its capacity to supply the production/bottling plant from 260m3/hr to 400 m3/hr. The £1.3-milllion project was led by Severn Trent Services as the main process contractor, with Dutch group Norit awarded a £300,000 contract to design, manufacture and install a membrane filtration and wash water recovery system.
As well as the higher capacity, the new system had to comply with the Coca-Cola 'red book' for water treatment that applies to the raw water coming into its factories worldwide, said Alan Ellis, UK project engineering manager for CCE. This, he noted, specifies exacting standards for water quality, including a turbidity of less than 0.2 and total chlorine content below 0.05 mg/litre.
The Wakefield plant uses mains-fed water from a Yorkshire Water surface water treatment plant, which is relatively high in organics at peak times and rainfall periods. The previous water treatment system, which was built in 1989, was based on lime coagulation and sand filtration, with carbon filtration for dechlorination and an ion exchange unit for organics scavenging.
This first-phase treatment at the Yorkshire site is required to raise the quality of incoming water to a semi-treated stage, before a phase II system of deaeration, cartridge filtration and UV sterilisation prior to bottling.
The move to adopt membrane filtration process went slightly outside the Coca-Cola rulebook, according to Dave Lumb, process team leader at the Yorkshire facility. The decision, he said, was taken on the basis that it offered significant operating benefits over the previous plant, which ran an approximate 90% wastewater recovery system and generated 700 m3/day of waste.
With the new system, incoming water from the mains is stored in two 800m3 storage tanks from where it is pumped to four activated carbon tanks containing a total of 66m3 of filter medium. It then passes through an ion exchange system to remove organics. The organic scavenging process is required as organic content is a key quality parameter of CCE's product make-up water.
"Although organic levels in the raw water supply are generally low, they are subject to seasonal fluctuations," Lumb explained. "We tend to see lower levels in the summer months and an increase in autumn and winter. It is at these times that the scavenger comes into its own and allows us to be confident that water used to create our products is effectively treated."
Feed water from the organics scavengers passes to the ultra filtration system; four parallel streams each with a normal capacity of 100m3/hr and a peak capacity of 133 m3/hr (see panel p24).
Control of the water treatment plant is integrated into the SCADA-based systems for the production lines. Information on how the plant is running is shown on a single screen along with information on parameters such as flow, pH, temperature, pressures, turbidity and chlorine levels at all stages of the process.
Permeate from the UF system passes through the semi-treated water tanks that supply the feedwater stock to the final stage of the treatment prior to the bottling lines. To meet Coca Cola's current rules the system has a 20-micron polishing filter after the water treatment plant, though this requirement may change with the use of UF filtration in the phase I treatment.
CCE runs the carbon filter for 96 hours between each backwash, the organic scavengers for 376 hours, while each of the Norit skids are operated three hours between each backwash. "The backwash is based on double forward flow, so we backwash it at typically 240-250 m3 through the Norit skid over a 30-second cycle," explained Lumb. Backwash water from the UF skids goes into a recycle tank and then through a Norit skid to clean it again in a continuous cycle.
The new water treatment plant went into operation in July 2006, with the previous facility decommissioned after six months of safe operation. The system, stated Ellis, is delivering a 50% increase in capacity with a wastewater flow of just 20-30m3/day — a 30-fold reduction in wastewater generated at the plant.
The plant has been recorded as 97.8% efficient, whereas the previous system was only reaching near to 95%, said Lumb, who added: "This is important. When you are dealing with 400 m3/hour, you could be throwing a lot of water away over the year." Water composition, he added, is much improved in that there is no coagulant there and disposal costs are reduced.
Another gain is that the new facility has a 50% lower footprint due to the use of membranes and the elimination of the membrane coagulation stage, which has freed-up space for a new juice production line.
The new water treatment facility is also designed for ease of maintenance, with all the pipework and valves located at low level, and even the light fittings in the roof space can be lowered down to ground level at the flick of a switch in the corner of the building.
"The plant was designed with the people who operate it in mind," explained Alan Ellis. "We looked at the activities that people have to do on the water treatment plant today and then took the process back to eliminate some of that work. We try to keep to this philosophy, building around the people who operate the plant as well as what the business needs, rather than just working to the lowest possible cost."
The UF systems at Wakefield
The Norit system comprises four skids with capacity to process 700 m3/day. The parallel units each house 24 Norit Ex-Flow membrane elements - a hollow fibre system based on an 0.8mm hollow fibre. This offers filtering down to the ultrafiltration range, which offers protection from bacteria and from viruses, including cryptosporidium.
The skids each comprise six 316 SS tubular pressure vessels, housing 24 SXL225 Norit X-Flow membrane cartridges, which are 1.5m long and 200mm in diameter. Each cartridge contains over 10,000 polymeric hollow fibre filters, 0.8mm in diameter with a filtration pore size of only 0.03 microns and an effective filtration surface area of 40m2. Each membrane is automatically tested on a daily basis and can be isolated and repaired without affecting the running of the plant.
