Four-layer filter delivers savings

An innovative filtration technology, first developed in a garage workshop, is bucking the current economic trend for Scottish firm Filter Clear. The Spruce Filter was the brainchild of the late Fred Spruce, a renowned chemical engineer with ICI in Cheshire, and its developers believe it is the only patented and commercially available four-layer filter system. Filter Clear was set up in 2003, with just three members of staff, to commercialise the technology. Six years later the company has grown considerably and, as well as increasing its staff threefold, is on course for a healthy turnover of £1.7M in 2009.

Managing director Nic Holmes, whose father Frank was a personal friend of Spruce, said: “It’s taken us five years of hard work, knocking on doors and piloting the technology to get to the stage we’re at now, but it is beginning to really pay off. The technology is becoming the benchmark for media filtration in the industry, and, once adopted, the impact of the product to companies, both financially and environmentally, outperforms comparative systems.”

Energy consumption

The combination of four layers is what makes the patented process. It gives specific flow rates and can achieve a flow-through velocity of 50m3/m2 (simple sand filtration is 10m3/m2). This higher rate reduces footprint, making savings across the process from energy consumption to the number of vessels needed to achieve throughput.

Holmes says that the 0.2mµ particle filtration means the Spruce Filter can compete with membrane systems for some applications and is being used for pre-treatment in desalination. The company has recently installed a pretreatment system on a desalination plant for oil and engineering company Saudi Aramco in Saudi Arabia, and is fielding a lot of interest from the Middle East. He says that replacing dual media with the Spruce system can cut the number of vessels needed by a quarter.

Closer to home, Scottish Water is the water company that has taken most interest in the Spruce Filter to date. A 2m-diameter filter was installed at the water treatment works at Loch Ascog on the Isle of Bute in August 2008. The 865m3/h system was designed for pre-filtering raw water prior to the slow sand filter to tackle the problem of algal bloom. A 1.2m polishing filter was installed on the tertiary stage before UV treatment at Luss wastewater treatment works on Loch Lomond last summer. The filter will help the plant cope with seasonal spikes brought about by the tourist industry.

Industrial applications focus mainly on the food and beverage industry with installations for two Scottish distillers now operating effectively. At Diageo’s Glen Lossie distillery a system was put in place to remove turbidity and algal bloom from feed water taken from a loch to the cooling towers. The installation meant the company could dramatically reduce its use of biocide chemicals. While at Old Poultney distillery in Wick, water taken from Telford’s Lade for whiskey production is now treated with a Spruce Filter.

Feed water for 1.6 million chickens, on Europe’s largest processing and packing egg farm in Telford in Shropshire, is also now treated with the Spruce Filter. Initially a manual Spruce 25 system was designed and installed to improve the filtration of lagoon water by an existing ceramic membrane and UV system.

It was then discovered that the water quality problem actually lay with the membrane unit. Drinking water quality can affect egg production, so after careful monitoring of both the filtered water and the laying rate, the membrane system was bypassed and the Spruce Filter water fed directly to the UV, and then the hens. The Spruce 25 is filtering 800m3/week at present.

Filter Clear says that eliminating the cost of mains water for livestock feed water, along with removing the ceramic membrane filtration and associated energy costs, is saving £100,000 per year. This has given Oakland Farm a remarkable payback of about six weeks on the Spruce Filter.

Holmes sees greywater recycling as another area of growth for Filter Clear and the company is developing a network of resellers for this area of business. Aquaco is one partner targeting recycling systems for large office buildings.

Greywater recycling

The Home Office in Sheffield has placed the first of these orders and a system planned for Watermark House will be the first greywater system in the City of London, Holmes said. The company is happy for approaches from other companies looking to resell the technology for greywater recycling.

The company is also operating in Ireland, Spain and the Netherlands, and recently developed a joint venture with a partner in China, where it is hoping to develop business in the near future. Holmes is optimistic that the environmental and economic benefits of the Spruce Filter will help the company grow despite the global economic downturn.

Holmes said: “The next few years will be crucial for Filter Clear. Our predicted turnover by 2010 will be defined by our international partnerships and investors and we’re really excited about the years ahead. Our vision is to become a world leader in the development and supply of water treatment technologies.”