Report : Water management
Environmental concerns as well as health & safety and the price of water and waste disposal make an investment in water management less of a difficult decision.
There were not too many new agencies taken on by the UK’s machinery suppliers at the Marmomacc exhibition in Verona this year, but the equipment of one water management company has been added to the agencies of Andy Bell of Stone Equipment International – and the plant has already found its way into a UK stone company.
The agency is for Dal Prete and takes Stone Equipment International into water management for the first time. Dal Prete is an Italian machinery company that moved into water management in 2001 because it could see water recycling was increasingly becoming an issue for stone processing companies. At the same time as stone companies became ever more automated with water guzzling CNC machinery, water was becoming more expensive, as was waste disposal, and environmental and health & safety pressures were increasing.
Since 2001, those pressures have only grown. And it is not just the larger companies that are having to address them. From the beginning Dal Prete realised that smaller companies needed easy solutions for their water management needs. That meant not only keeping the systems simple to operate and low cost to buy and install, but also minimising the space they take up in the workshop or yard.
But Dal Prete did not want to compromise on the efficiency of the plant that was being used by smaller companies, so even its smallest Super Compact system has a filterpress (with four 300 x 300mm plates). Inside the silo is an agitator for the preparation of sludge to be transferred to the filterpress. It can process 150litres of water a minute and press 0.8m3 of sludge in an eight-hour shift.
The filterpress has a protective, stainless steel casing and includes an automatic plate shaker to clear the squeezed sludge. The system uses flocculants and includes a 100litre capacity automatic dosing station that is operated by a minimum level sensor.
The system is transported complete so requires minimal installation. The low level square silo maximises decanting in minimum space. The plant is computer controlled with touch screen management. It is ideal for small processors making kitchen worktops or for companies operating a couple of CNC workcentres that use a lot of water but do not produce a lot of sludge.
At the other end of the scale are traditional systems as large as plant with silos that have an 8m diameter and filterpresses with 30 plates that can process 7,000litres of water a minute. A system of this size would be designed specifically for the site it was going into. It would have separate water clarification and sludge dewatering functions with a sludge pump to load the sludge into the clarifier.
Filtered water is fine for general cooling and lubricating functions on stone but you would not want to use it for the mandrel of a CNC workcentre because the small particles of stone left in it would quickly abrade the bearings of the head as well as effectively increasing the grit size of polishing tools. Generally, tap water is used, although that is changing.
Some people have tried cartridge or sand filters but they can clog, so water management companies have come up with systems specifically for use with CNC workcentres. Dal Prete has two versions that it calls Just Water, one that filters to 20microns and one to 5microns. And if you need more water than one can supply, two or more can be used together.
They are easy enough to use as they contain software that automatically controls their cycle, including backwashing. And they are made of stainless steel so they have a long life with minimal maintenance requirements.
Having taken on the Dal Prete agency, Stone Equipment International showed it to a customer, Steve Buck of Marble Ideas in Langley, Berkshire, who had visited Verona with the intention of buying a fourth four axes Emmedue, also sold by Stone Equipment International. With more machinery, Steve decided it would be a good idea to replace his bag water filtration system. The week after Marmomacc Dal Prete visited the Marble Ideas factory and the new water management system is currently being installed.
www.stoneequipmentinternational.com
Earlier in the year, another move in the water management equipment supply sector saw D Zambelis take on the agency for another Italian company, ItalMecc.
ItalMecc had not had an agent in the UK for a while, although it continued to field enquiries from the UK from Italy.At Marmomacc this year it introduced its most compact system yet in an effort to help smaller stone companies benefit from more efficient water recycling.
Called Blucomb it is a lamella water clarifier made in stainless steel or Polystone. It can be used with a bag filter or automatic filterpress, with or without the use of flocculants.
And if you are wondering what Polystone is, it is a form of polypropylene more commonly used in pharmaceuticals. It has an extremely smooth surface so sludge does not stick to it, has a high resistance to shocks and breakage from mechanical stress, is abrasion resistant, has electrical and thermal insulating properties, is not attacked by the chemicals or acid in the water (a silo made of stainless steel can be degraded by electrical conductivity or acidity), does not absorb water and will not cause bacteria proliferation.
The silo is square to make the best use of limited space and designed to maximise sludge removal while cleaning the water as quickly as possible – it processes 100-120litres a minute.
The whole unit is easily delivered and installed with minimum civils required unless you need a storage tank to hold water because you are producing more than the 4,000litres the Blucomb silo can hold. It is also sensible to filter out any large lumps of material before the water enters the silo or you could damage the pumps, which are about the most expensive element you will ever need to replace – certainly a lot more expensive than fitting a filter.
The Blucomb requires minimum maintenance because it is self cleaning. It has air pipes under the lamella packs that blow bubbles up through the water to clean the lamellas when the system is not being used. A programmed automatic valve will then remove the sludge either to bags or a filterpress.
Installed, the Blucomb stands at less than 4m high and just over 3m wide. The price starts at around £10,000.
And this is just the latest in a wide selection of water management systems from ItalMecc that are now available from D Zambelis.
Like other companies selling water management systems, ItalMecc also sell water-based dust control systems and introduced a new product, called Magnum (pictured left) designed to improve dust collection up to 10m from a waterwall. Stella Zambelis says she sold three of the units during Marmomacc and plans to keep one in stock in the UK for speedy deliver to anyone who needs one.
New Stone Age in Keighley, Yorkshire has represented OMEC, the Italian water management equipment company, in the UK for more than 10 years. In that time, these water recycling systems have become the solution of choice to many in the stone processing industry, which has given the plant an undisputed track record.
New Stone Age has now installed more than 20 of these water management systems, giving Managing Director James Turton and his team full knowledge and understanding of supplying correctly dimensioned and appropriately specified plant to satisfy the special nature that UK stone presents.
What customers say they particularly like is the way the systems are made as bespoke solutions to their particular needs, now and into the future, with full technical support from both OMEC and New Stone Age.
Because frost is not unknown in the UK, OMEC provides fully enclosed silos that offer good weather protection for the valve gear and controls. The filterpress is also supplied in a fully enclosed and insulated housing, along with steel support columns that mean you don’t have to build your own concrete walls before the equipment arrives.
There is stainless steel pipework as well as galvanised structures, which are important to protect against the abrasive nature of some materials being processed and the salts that can be present in the flocculents used to aid the settling out of solids.
Redundancy is built into system critical components, especially the sump pumps, so the water management system will not bring your production to a halt in the case of a failure or when a pump needs servicing. Two sump pumps, working and on stand-by alternately so you know they do both work, is a sensible safeguard.
Some companies choose their own clean water pumps, but if OMEC is supplying them, it will include two of these as well, again so that a failure or maintenance will not bring your production to a halt.
The OMEC filterpresses have particularly large spaces between the filter plates. This produces thicker cakes than you will get with many systems, the advantage being that their own weight will clear them from the press without the need for shakers. That means fewer moving parts, which, in turn, means less maintenance, less to go wrong and fewer parts to replace.
Once an OMEC water management system has been installed, it pretty much runs itself, including an automatic flocculent doser. And because it is designed specifically for each installation it is neat – ie it does not have wires and pipes running all over the place to get snagged and broken.
The automatic flocculent dosing pump injects a metered dose of flocculent. This is important to ensure the system will give good water clarification without overdosing. If the flocculent is overdosed, it can lead to the mud settling out too early, leaving deposits around saws or in drainage channels. Overdosing can also cause corrosion of machinery, especially if the machine is not earthed correctly, resulting in a galvanic reaction.
The flocculent is normally added to the dosing tank as a powder, perhaps twice a week (depending on your production rate) and should take no more than five minutes.
With bigger plant it is worth having an automatic flocculent preparation system, which automatically mixes the flocculent from a hopper.
Flocculent costs about £1 per 100L/min per week on average. That means a 500L/min system will cost around £5 per week.
The OMEC range caters for all sizes of businesses processing stone, granite and marble. Whether you have a small workshop supplying granite worktops or masonry, or a large factory working stone from quarry blocks, there is an OMEC system that will suit you.
New Stone Age understands that not all customers have the same production techniques and advises on the correct size of not only the silo and pumps (in terms of litres per minute), but also the varying percentages of mud for a given flow rate.
The table on the previous page is a useful guide to the combinations of water cleaning systems (silos and pumps) and the size of filterpress for mud dehydration.
The ‘High Technology’ range of OMEC filterpresses includes a new diagnostics touch screen on the press that monitors the complete system. This enables the operator to identify quickly any problems or maintenance requirements, photographically identifying the exact location of the problem and providing instructions for the response required.
You can also choose when the filterpress will be working throughout the week, so it does not work when it is not required. That way the system is always working at an optimum state for efficient pressing of the mud. This minimises maintenance and cleaning and increases the life of the pressure pump and filter cloths.
OMEC has even included coagulant dosing systems into its plant to improve still further the water clarity when dealing with different materials in the same factory. This can be important to customers who are processing both dark and light coloured materials and do not want contamination when switching between the two.
Until now, it has been advisable to feed fresh water into the spindle of CNC machines because filtered water could still contain particles that could scratch the surface of the work and wear the spindle bearings and seals.
But OMEC has developed filters to remove microscopic particles, so spindles are fed with water that will not damage the seals and bearings nor scratch the surfaces of polished marble or granite.