Arguments for improving the management of the copious amount of water modern stone sawing and processing machinery uses are winning the day. No longer able to afford to use fresh water from the mains or to get away with pouring the waste down the drains, companies are seeing the financial as well as the environmental benefits of investing in what has previously been seen as ‘dead money’ because it does not appear to bring an immediate return on investment.

There has often been some resentment involved in investment in water management solutions because, unlike a new saw or workcentre, it does not seem to play a part in improving the output of the factory. As a result there are a lot of home made Heath Robinson systems to be seen in stone processing factories. But that is changing.

Investment in better water management often coincides with the purchase of new machinery. Clean water increases the lifespan of machinery and when you have just paid out at least tens and perhaps more than a hundred thousand pounds on new machinery, you are acutely aware of not wanting to accelerate its demise by putting dirty water through it.

Spending £20,000… £30,000… perhaps even £40,000 on a water management system might still raise resentment because it can be hard to quantify the benefits of the investment. Nevertheless, more and more companies are biting the bullet and doing it because they know deep down they really have to.

There are more benefits than extending the life of machinery. Who hasn’t resorted to a few choice words when dirty water has left scratches on an otherwise perfectly polished surface?

The bills for disposing of the sludge from a sludge tank, most of which is just water, can also concentrate minds. Adam Stone, the Managing Director of Chichester Stoneworks, is just about to install a new water system with a filter press at the old CWO works in Chichester that Chichester Stoneworks now operates.

Adam has calculated it will save the company £15-20,000 just by not having to pay so much to dispose of what is in effect dirty water from the sludge tanks. It will also improve the working environment, he says, because it will remove the sludge underfoot in the factory, which has a health & safety benefit.

Neil Sharkey, of Pat Sharkey Engineering, which now sells water treatment plant from Sigma Group, says: “Our message is simple – you are throwing away your money as well as the mud if you do not have a water treatment system. An efficient water treatment system can pay for itself within two years.”

Water management systems, often including waterwalls for use in workshops, are sold in the UK and Ireland by many of the same companies that supply machinery.

Often the civil engineering and pipework required is organised by the masonry company having the system installed. It depends on the system, but this work can be quite substantial.

The company making the system will normally design it and let the customer know what will be required in terms of pipes and civils. Most of the growing number of masonry companies that have now installed such systems praise the help they get from the (usually Italian) makers of the system and their British agents.

The systems vary in capacity, price and sophistication. Some use flocculents that encourage the particles suspended in the water to precipitate out, although flocculents can corrode metal, especially the cheaper flocculents based on aluminium polychloride, a salt that will rust ferrous metals. It is advisable to use galvanised or stainless steel pipes and silos.

The best known water management systems in the UK and Ireland are those of Turrini Claudio, sold by D Zambelis and Accurite; Omec, sold by New Stone Age; Martini Aeroimpianti from Waters Group; Fraccaroli & Balzan, from Roccia and Ital Mecc, where enquiries from the UK and Ireland are currently being dealt with from its headquarters in Italy.

There are other water management systems but an advantage of choosing one already widely used by other stone companies is that the suppliers are familiar with the requirements of a wide range of stone processing, from worktops to primary extraction.

And the systems continue to develop. In the past it has not been advisable to put recycled water through the centre spindle of a CNC machine but lately equipment has evolved to give the water an extra scrub so it can be used for all requirements.

On the Turrini Claudio plant it looks like a large gas cylinder and is called the automatic monovalve filter. The water coming from it is certainly clear and it is lime free so it will not furr up pipes and machines. It is said to be clean enough to drink, although you might decide to take Turrini Claudio’s word for that.

Stella Zambelis of machinery, tools and consumables company D Zambelis says the most important aspect is buying the right system for your workshop and making sure everything is in place to avoid losing water from the system. “If you haven’t done your homework and you’re wasting water, what’s the point of having it? You lose some water, but it shouldn’t be much.”

Stella says Turrini is user friendly, with clear manuals showing what is required and help available over the telephone from Italy, although there are plenty of people at the company in Italy who speak English well.

Riccardo Turrini says: “We have a great knowledge of the UK market because we started in 2000 with Ebor. My brother, Alberto Turrini, started to work at the age of 16, flying twice a week to the UK installing water recycling plant, so we feel a strong relationship with UK workers.”

The company offers a wide range of water management solutions, from 50litre/min to 20,000litres/min. In the UK the most requested systems are the DEP 350, 500, 600 and 800, although the company’s first UK customer, Marble Building Products (which bought an MB 40 in 1996) now has a plant processing 2,200litres/min.

Riccardo explains the Turrini Claudio system: “We provide our customers with a submerged pump (usually Ebara, but also PEMO Perissinotto, depending on the water flow) to put inside the dirty water tank. If the customer does not have a dirty water tank, we can provide it. We usually suggest a 600litre circular tank with 1.5m straight sides at the top and a 1.5m conical part at the bottom so the sludge will flow toward the submerged pump, although the size will depend on the customer’s requirements.

“The submerged pump removes the sludge into a silo, where it is helped to settle by a flocculent injected by a 0.5litre/min flocculent pump. The flocculent needs about 25-30minutes to work well inside the silo.

“The size of the silo depends on the water requirement. For 350litres/min, you need a 10.5m3 silo, for 500litres/min, a 15m3 silo and for 600litres/min about 18m3. But, pay attention, this is not a mathematical rule! It depends on the quality of the flocculent and the contaminant in the water. Moreover, we calculate the flow rate the customer needs as if all the machines are working (which is quite improbable) and for every machine we calculate a little higher water consumption that it actually uses, so if the customer changes a machine or buys one or two more, the water recycling plant will continue to work well.”

Riccardo has some advice about flocculents. Those supplied by his company cost about €10/kg and a typical customer will use 10-15kg per year. There are flocculents that cost as little as €3/kg, but he says they are more corrosive and can rust the metal of the system.

There are also different flocculents for different contaminants, which could make life difficult as companies start processing a greater variety of materials. There are those that work best with granite and quartz, others for marble and limestone, others still for ceramics. “All the materials need something specific in order that the plant works well,” says Riccardo.

If you leave out the flocculent, the water needs 60-80 minutes to settle, so you need a larger silo to achieve the same flow rate.

In 2010 Turrini stopped making silos with lamellar packs because it decided the extra maintenance they required was not worth the extra 30-40litres/min they produced. Also they rusted quickly, so now there is only the classic stainless steel ‘bell’ inside the company’s silos.

If the silo is high enough – for example a DEP 600 C that is 6.2m high – there is a pneumatic valve (in anti-abrasive rubber, made in Italy by Blue Valve) because the water pressure is sufficient to push out all the sludge. In smaller silos the water pressure alone is not sufficient and a pump is necessary. There is also a pneumatic inlet, so if you shut down for a fortnight without discharging the silo first you can break up the sludge with a shot of air.

At the bottom of the silo there is a manual valve so if the sludge pump or the pneumatic valve need maintenance you can empty the silo.

The clear water going back into the system for the machinery comes from the top of the silo. Before it is recycled it is filtered to remove floating debris (such as pieces of wood or cigarette filters) that can block or damage the clear water pumps.

Turrini provide two clear water Ebara pumps, so there is always a back-up for emergency or maintenance.

The systems are all fully automatic and new this year is a digital Telemecanique switch pressure sensor, which makes controlling the pressure on the clear water pump’s a lot easier.

For bigger plants there is an optional Magelis touch-screen panel, ABB inverter for saving electricity, ultrasonic level switches, continuous flocculent mixer (managed by level probes and automatic dosers) and a pH control station (because the flocculent works better if the water pH stays within certain limits).

Turrini also makes waterwalls and has sold 35 of them in the UK so far this year. It is currently developing a new waterwall dust suppression system with PVC spiral nozzles that it plans to introduce to the market next year.

Pat Sharkey Engineering sells the water treatment plant of the Italian Sigma Group, which manufactures bespoke systems as well as its range of standard filtration plant and equipment.

Water treatment systems fall into two distinct sections: Sludge dehydrators, which take the water out of sludge so you are not paying to dispose of it; depuration plants, which separate out solids suspended in water. Each may incorporate an automatic filter press.

The dehydrators from Sigma Group are an effective way of separating the solid waste from the water. The water is clarified in holding tanks or silos before being pumped into a special distributor and onwards to the filtering bags or filter press.

The filtered water returns to the clean water holding sump and the solids remain in the filter bags to be disposed of once full and suitably drained or processed by a filter press to produce semi-dry cakes of waste that can be disposed of.

Sigma Group dehydrators are available in a variety of sizes to meet small and large manufacturing needs. Starting with the DS20 (with two, 90litre bags) through to the DS-60 (with eight, 90litre bags). Those who require even greater volumes can opt for the 2-DSM system, which uses two, 2,500kg bags.

The filter press system from Sigma caters for high volumes of slurry generated by large production plants. It is an automatic process, separating the mud from the water using a storage silo, clean and dirty water reservoirs and a hydraulic filter press.

The system ensures that the water is continually processed, with or without the use of a flocculent. The semi-dry cakes of waste from the factory are discharged into a skip for disposal. When it is largely dry, the stone waste is treated as inert, when it is wet it is categorised as hazardous because it can form areas in landfill sites that can slip. Disposal costs of semi-dry cakes are minimal compared with the cost of disposing of the sludge from the bottom of a settlement tank.

Winter protection of water management plant is important. Sigma Group offers a full winter insulation package, something that has been carefully specified to meet the needs of customers in climates such as Norway, so the UK is not a challenge in this regard.

The Sigma Group plants are available from 150litres/min through to 800litres/min and Pat Sharkey Engineering provides full onsite investigation, specification and quotations.

OMEC, again from Italy and sold in the UK by New Stone Age, supplies systems that have been particularly popular with larger companies. Now, though, they are also becoming popular in smaller installations such as the 500litre/min system at Traditional Stones pictured on the cover of this issue of NSS (details of it below).

What customers particularly like are:

• Correctly dimensioned systems to cope with the customers current and future requirements
• Advice and bespoke design provided by New Stone Age on the water distribution in the factory (even though OMEC does not normally install the pipework in the buildings)
• Fully enclosed silos offering good weather protection for the valve gear and control equipment
• Fully enclosed and insulated filterpress house
• Stainless steel pipework
• Galvanised structures
• Redundancy on system critical components (sump pumps and clean water pumps)
• High level of automation
• Good technical support from both OMEC and New Stone Age
• Clean installations (not many wires or pipes running everywhere)
• Technicians arrive with a full toolbox so the customer does not need to give much assistance during installation (apart from supplying a crane).

The most recently installed system went to Tradstocks in Scotland in July. It comprises an OMD30 (30m3) water cleaning silo, an OMF814 filterpress with 14, 800x800mm plates and a transfer pump. It has a 1,400litres/min water treatment capacity and 10m3 a day sludge capacity. It will accommodate all the machinery the company intends to install and allow for future expansion.

The silo is fed by the usual two sump pumps (one working and one on standby at any one time), each delivering 2,200litres/min to ensure a good pause time to let the mud settle correctly in the silo.

There is a 1,000litre flocculent tank that automatically doses when required and uses £10-20 of flocculent a week.

There is a waste water transfer pump in an independent well because the site is 80m from the water treatment plant.

The OMF 814 filterpress is fed by a Pemo Impellor pump that has a special stainless steel impellor designed by OMEC to reduce wear. It is, like all OMEC filter presses, fully enclosed on a steel platform all supplied by OMEC. It is fully automatic, analysing the consistency of the sludge being pressed and determining when the next press needs to be made. It will not do more than a certain number of presses, based on the capacity of the discharge container.

Tradstocks already had an OMEC OMD 20 (20m3) water cleaning silo and pumps on the site that New Stone Age supplied in 2004, and the new filterpress is processesing the sludge from both the existing and new silos automatically. This is programmable, so the operator can specify the ratio of discharges from one silo to the other.

Another of the latest OMEC systems to be installed is at Farleigh Masonry in Wiltshire. There, an OMD30 R (30m3) silo plus an OMF610 filter press with ten, 600x600mm plates has been installed. It can treat 800litres/min of water and 4m3 a day of sludge. The plant easily copes with Farleigh’s current maximum requirement for 650litres/min and allows for future expansion.

The two sump pumps can each deliver 1,000litres/min, ensuring good pause time to allow the sludge to settle in the silo. There is a 300litre flocculent tank that automatically doses when required. It uses £5-10 of flocculent a week.

The OMF 610 is powered by a Yamada pneumatic piston pump. This is an automatic filterpress carrying out a predetermined number of presses based on the size of the sludge discharge container. If the silo is emptied of sludge the press will stop and wait for the operator to restart the cycle.

Another new system has gone to Traditional Stone in West Yorkshire. There, the OMD 10 water cleaning silo and OMF604 automatic filter press with four, 600x600mm plates has a 500litre/min water treatment capacity and a 2m3 a day sludge capacity.

The silo is fed by three sump pumps, two working and one on standby, that deliver 600litres/min. A 300litre flocculent tank automatically doses and also has automatic flocculent preparation that mixes the flocculent when required. The flocculent costs £2-5 per week.

The latest Fraccaroli & Balzan water management system to be installed has gone into stoneCIRCLE’S new workshop in Basingstoke, Hampshire. Managing Director Steve Vanhinsbergh chose the Fraccaroli & Balzan system because it came as part of a package that included three new GMM saws, a Brembana CNC workcentre and stone handling cranes all supplied by Roccia – and as a package it came at a good price, says Steve.

While stoneCIRCLE was building its new factory it decided to add a rainwater collection system from the roof. As the factory is 72m long, it would normally have had several downpipes from the gutter, but the collection has been designed to bring the rainwater to one end for collection in a large tank.

The tank happened to be installed in one of the dryest Septembers on record, so had to be filled initially with water from the mains. There has been no trouble keeping it topped up with rainwater since then. It supplies the clean water to the spindles of the CNC workcentres that previously came from the mains.

The Fraccaroli & Balzan recycling system delivers 1,000litres a minute of cleaned water for the factory’s seven saws, three workcentres, waterjet cutter and three edge polishers. A bagging system rather than a filter press is used to collect and drain the sludge, with the bags currently being changed every other day, although all the new machinery has not yet been installed in the workshop. Even when it is all in, the system should have enough capacity to accommodate any future expansion or additional machinery.

The only fault Steve considers the system has is that it is not responsive. He thought if his shower at home was capable of turning on pumps when the water was turned on it ought to be possible to do the same in his workshops. Roccia agreed and Fraccaroli & Balzan’s engineers are now installing switches so the pumps will be turned on when a machines need water and turned off when they don’t.

Fraccaroli & Balzan water recycling systems have been sold in the UK and Ireland for a long time and there are a lot of them in stone workshops and quarries. And there are likely to be even more in stone company workshops now that Fraccaroli & Balzan has started making simple, compact systems in the £20,000-30,000 price range for smaller granite and quartz processors.

“If people are buying a new bridge saw or CNC workcentre they might as well sort out their water treatment at the same time,” says Roccia Director Darren Bill.

A final word about Ital Mecc, another Italian water recycling plant company. It has been represented by various companies in the UK over the years but does not currently have an agent in Britain. It says it is dealing with enquiries from the UK and Ireland at its headquarters in Italy. If it is your preferred supplier, you can contact the company through its website and it will communicate in English.