Water Management : Clean, green and economical
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Company: Hutton Stone, Berwick-upon-Tweed
System chosen: Omec
Supplied by: New Stone Age
Two severe winters up near the border with Scotland convinced Marcus Paine, the Managing Director of Hutton Stone, that he had to update his water management system. Settlement tanks had a pump for each saw lowered into the water on ropes. They distributed water through a system of pipes that had grown organically as machinery was added and just were not up to the job any more.
“Last winter we were in meltdown,” says Marcus. It was not that production could not continue as temperatures dropped to-17ºC – most stone sawing would stop in such extremes – but how the water management system behaved coming out of those conditions. The way the old system behaved was enough to convince Hutton Stone it needed a better way of handling its water distribution, especially as all the fresh water used on site was coming from the mains and being paid for through a meter.
Marcus started looking around at water management systems. “We looked at various versions and, I don’t know, New Stone Age made it very straight forward. James [Turton, the Managing Director of New Stone Age] helped us to understand more about what we were trying to achieve and presented us with options for how to achieve it.
“It wasn’t the cheapest system, but we always try to buy the best we can afford and felt the Omec system was the best. It wasn’t simple, either, but New Stone Age and Omec gave us the engineering answers we needed. And their back-up has been excellent. We haven’t needed much, but whenever we’ve had a question New Stone Age has been here with the answer.”
Before making the final decision, Hutton Stone visited an existing Omec installation at York stone company Gillson in Haworth, which proved useful. They learnt, for example, the value of having the filter press in a heated room, which would extend its life by as much as five times.
With the help of New Stone Age, Hutton decided it needed a system that had the capacity to process up to 700L of water a minute. That required a medium sized filter press, which would accommodate the 2m primary saw, monoblade, 800mm and 1200mm secondary saws and milling and routing machine that Hutton already had and would have enough capacity to cope with an extra 1200mm bridge saw and another monoblade should they be required.
The new system has two pumps to deliver water to the machines, but they are used one-at-a-time to deliver a predictable 3bar pressure through the use of throttle valves to all the machines. The pump not being used is a back-up to ensure production is not disrupted in case of problems. Each pump is operated for a week alternately so neither deteriorates through lack of use. They are both above ground, rather than swinging from the end of a rope in a sludge tank, and are switched so it is easy to change from one to the other.
The Omec system uses flocculents and all the new pipework is in stainless steel and the Omec structure is galvanised to protect it against the flocculent.
The deal was concluded in March but a problem with replacing an old water management system is that it is likely to disrupt production as the new system is installed, so the changeover had to wait until Hutton Stone had their normal fortnight’s shutdown in August.
Marcus says New Stone Age and the Italians from Omec who came to install the plant did everything they could to fit in around Hutton Stone’s schedule.
The Italian engineers built the new system on a platform next to the old plant. It has service pipes with electrics and air set into a 200mm thick concrete bed and a 2.5m deep well to collect dirty water.
The engineers then went away for four days while Hutton connected it up to all-new lagged pipes supplied by New Stone Age to feed the saws.
Marcus: “The Italians came over, built it, gave us a demonstration and that was fine. But it takes two to three months to work out how to make it work really well for you – things like: do you press first thing in the morning or last thing at night. It’s about understanding the sort of sediment you produce. Then there’s draining out; the flocculent mix. But it’s a beautifully clean way of dealing with the messiest part of the operation.”
There were some more lessons learnt from this winter. Up until this month (February) the weather had been kind, but just severe enough to highlight some changes needed to protect the system when the weather turned colder.
For example, they moved the heaters so the diaphragm pump will not freeze. And they learnt the benefit of draining and blowing out the pipework each night. They have now introduced procedures to make sure that happens as a matter of course.
“We were aware we would learn from the frosts when they came this year,” says Marcus.
The cost of installing a water management system like this varies from one installation to the next, depending on the size of the plant, the peripherals required and the civil engineering necessary.
The largest system New Stone Age has supplied is capable of processing 2,000L a minute. At the other end of the scale, the company has just started selling a compact, stand-alone system called Kompact Complete. It has a silo and small filter press and can process up to 500L a minute – just right for a primary and two bridge saws. It costs about £30,000, including the civils.
Unlike buying a new saw, there is no immediate improvement in output from the factory to demonstrate what a good investment water recycling plant is. But the financial benefits, as well as the environmental benefits, accrue over time.
There are savings often of hundreds of pounds a year on water from the mains. There are savings on cleaning out sludge from settlement tanks and disposing of it. And because the recycled water is often cleaner than it is from settlement tanks, machines and tools last longer.
And the saving in a reduction of
down-time is incalculable, both in terms of less lost production time and fewer dissatisfied customers.
Company: Hoare Banks, Bournemouth
System chosen: Martini Aeroimpianti
Supplied by: Waters Group
Hoare Banks wanted a water recycling system to process the water needed by the company’s Thibaut GB110 polisher and 108S workcentre, GMM Brio 35 saw and jenny lind, and the polishers and pillar drills being used by up to eight masons at a time in the workshops.As the stonemasonry and memorials company was already a customer of machinery, tools and consumables supplier the Waters Group, that was where it turned for a suitable water recycling system.
Waters sold them the 400L a minute Lindo Compact from Martini Aeroimpianti, the Italian water management company that Waters represent in the UK.
Mike Farwell, Hoare Banks’ Works Foreman, says the workshops use up to 200L of water a minute, and while Hoare Banks currently have no plans to expand, the company wanted the system it installed to have some spare capacity to be able to accommodate any future expansion.
“We spoke to other people about different systems and while cost comes into it to some extent, the main reason that pointed us to Waters was that with its system we could double the machinery we have here and it could still cope with it. And it’s a compact unit. Others we looked at were nearly twice the size and twice the price. Waters did a good job of selling it to us but everything they said has turned out to be justified.”
Essentially the message from Waters Group was that the system is simple, both to install and to operate. It does not use flocculents, so there are no chemicals to worry about. To clean the water, four taps are simply opened at the end of each day and overnight the contaminated water filters through the bags so that recycled water clean enough for polishing is available in the morning.
Used water from the machines and masons is collected in a channel running along the workshop and once a week a hosepipe is used to help slurry that builds up in the channel on its way.
A new 1.5m3 sump was dug to store contaminated water. Waters had recommended a 1m3 pit, but Hoare Banks decided it would be better to build in extra capacity now rather than have to revisit it at some point in the future if more machines are installed.
There is some natural wastage of water in the workshops – from evaporation, if nothing else – and the level of water is checked every night and topped up from the mains periodically. Mike says it requires about half a tank-full of water a week.
The Lindo system has no moving parts to suffer from wear and tear apart from an autoclave pump. Regular maintenance simply involves the removal of sludge using the special pump supplied with the unit.
Waters offer two versions of the Lindo, both of which can be used as stand alone systems or added to existing systems to increase water management capacity
Hoare Banks was not recycling water until the Lindo Compact was installed. The company used fresh mains water that drained into settlement tanks, the sludge at the bottom of which had to be collected and disposed of periodically.
The trouble with changing procedures is the disruption it can cause and Hoare Banks was too busy to want to shut down. But the transition turned out to be easy. New pipework was installed in advance. The Lindo turned up one day on the back of a lorry, was unloaded, connected up, and the water from the mains disconnected.
“The connection was made in October and it worked perfectly straight away,” says Mike Farwell, “and we haven’t run into any problems yet. It was an upgrade we needed to make and we’re very happy with how smoothly it’s gone. We didn’t have to shut down at all.”
An additional benefit for Hoare Banks has been that the removal of the old settlement tanks has allowed the workshop to be reorganised, so the workflow through it is now more efficient.
Company: Lovell Purbeck, Langton Matravers
Suppliers: ECS and Fraccaroli & Balzan
Lovell Purbeck has two water treatment plants at its factory on Purbeck – a 500L-a-minute lamella system from Germans ECS and a 1,000L-a-minute Fraccaroli & Balzan flocculent system that came with the 70m Donatoni tile line Lovell Purbeck installed last year to produce 100m2 of floor tiles a day.
Lovell Purbeck chose the ECS water management system to replace its settlement lagoons because it does not require flocculents, which the company was keen to avoid as they can accelerate the rusting of machines (although suppliers say this is less of a problem with the latest generation of flocculents).
Instead, the ECS plant uses the lamella construction (a series of plates) inside the clarifier. This provides physical water clarification. The clarified water flows into the fresh-water storage tank via an overflow and is returned to the production machines by a pump.
The separated sludge is pumped to the filter press by a sludge pump. As Purbeck is limestone, the dried waste is disposed of by giving it to local farmers who use it to reduce the acidity of their fields.
Lovell Purbeck chose the German water management system because it was recommended by another German company, Löffler Engineering, when Lovell was considering buying a Löffler saw.
Lovell has also installed a rainwater collection system with a 50,000L tank and has put solar cells on the factory roof. It all helps establish the company’s sustainability credentials and enhances its reputation for working responsibly.
As far as Director Simon Hart is concerned, the £45,000 water recycling system was a no brainer. It was not just a question of reducing the company’s £1,800-a-year water bill, it was also a question of good housekeeping and preparing for the expected future growth of the company.