Finding the Benefits of Filtration

Sophisticated water filtration systems are set to become an increasingly important tool. Muriel Axford reports on how the chemical industry is seeking solutions to reduce and improve water usage.

Chemical-focused businesses the world over are seeking to reduce and improve their water usage and in response filtration and membrane systems are becoming increasingly complex. Some in the industry say, however, that the true benefits of these technologies are not being fully appreciated at government level despite the growing demand.

For environmental protection the impact of these technologies has a two-fold effect, according to Industrial Purification Systems (IPS) managing director Steve Cupples. "Firstly, appropriately applied systems can lead to better usage allowing water to be cleaned," he says. Where possible, this water can be used again within a process rather than sending it into the drainage system.

"Secondly, there is an implication for the carbon footprint. It has to be remembered that water usage can be energy intensive. Most water is treated with expensive chemicals and can be heated or chilled, both of which require additional energy. Improvements in use could therefore lead to reduced energy output."

Cupples says he is concerned that as yet there is not enough focus, particularly within governments, on this potential for a dual benefit despite a growing demand for more efficient filtration solutions. His conclusion is backed by a recent study from consultancy Frost and Sullivan that looked into the South African market. The South African Membrane Market report says that membrane technology is becoming increasingly important in the area of water and wastewater treatment applications in the country.

"Most water is treated with expensive chemicals and can be heated or chilled, both of which require additional energy."

Counting the costs

The report divides the industry into industrial, municipal and commercial markets. "There is mounting evidence that membrane technology presents a viable option for water and wastewater treatment as industrial end users are increasingly using membrane technology to manage their wastewater streams," it says.

Along with the untapped potential for desalination, the report says that the treatment of ground water in the mining sector has also influenced growth in the membrane market.

Despite more widespread use – and lower capital and operating costs of membrane plants – the report acknowledges that for many companies costs are still prohibitive. "Besides the high capital cost, membrane plants are very expensive to maintain. On average membrane systems have to be replaced every three to five years and at the same time they need to be cleaned on a regular basis to remove foulants," it says.

This area is where Cupples says government assistance could make the difference. "If there was a focus on the big picture we could see major reductions on energy and the use of potable water for industrial applications," he explains. "However, the high costs and the lack of incentives mean that many water-intensive industries are yet to be convinced of the financial benefits of filtration systems, even if the environmental benefits are clear."

Cupples cites examples such as reduced efficiency of water-based heating systems where contaminated water means that increased energy is needed to maintain required temperatures. A system to clean the water would improve efficiency and reduce energy use. "A high initial outlay can mean large savings in just a matter of months," he adds.

Appropriate technologies

The pressure is on to move away from potable water for industrial applications. Sources such as bore holes, grey water and rain water are all viable options if the water can be made useable for the particular applications. "Bore holes can be a good option for many industrial processes but the problem of contamination means that reliable high-efficiency filtration has to be in place to make the water of a useable quality," says Cupples. He also highlights the numerous processes in sectors from food to pharmaceutical where the quality and purity of the water has become an increasingly important factor.

"There is mounting evidence that membrane technology presents a viable option for water and wastewater treatment."

It is this push to improve water quality and the desire to remove a wider range of contaminants that has driven developments in filtration technology towards being able to filter out smaller and smaller particulates. Whatever the technology implemented, filtration, membrane or a combination of both, there is a growing perception that filtration has a key role to play in helping to tackle the growing issue of water security.

UK-based IPS is a major player in the filtration technology sector. It is working across a wide range of industrial sectors around the world to develop and install appropriate filtration solutions for its customers. In particular, the company has made its mark in the uPVC window space where 90% of the UK's manufacturers of have implemented IPS technology.

Cupples says that producing uPVC window sections typically uses 200, 000l of water each hour. This water is treated with chemicals as well as being chilled to 12–14°C, making it a very energy-intensive process. To try and address the issue of contaminated water companies would undertake an overflow of 20% of the water volume each hour, then pay for fresh water at a rate of 40,000l per hour in addition to having to pay for contaminated water.

Installation of the appropriate filtration technology can lead to a near-zero-loss water system along with reduced effluent charges, chemical use and electrical energy. Cupples says that a return on the investment can be achieved within less than six months. In addition, improvements can be seen in the final product.

Tomorrow's systems

While helping customers to meet the ongoing challenges of reducing water usage, IPS is also committed to innovation.

"Installation of the appropriate filtration technology can lead to a near-zero-loss water system along with reduced effluent charges, chemical use and electrical energy."

In collaboration with the UK's Liverpool University and the UK Government's Business Enterprise (BERR), IPS has been involved in the development of a high-efficiency media filtration system. Called the CrossFlowMF1.0, the system enables the reuse of process water and municipal wastewater or use of alternative water sources such as borehole and rainwater harvesting. The system is already in use within a distillation facility and a petrochemical plant located in Saudi Arabia where it is used for "effluent water polishing".

The efforts made by IPS and its collaborators in developing the CrossFlowMF1.0, said to be reliably capable of filtering particles down to 0.45 microns, was recognised when the team came runners up in the 2009 Merseyside Innovation awards. CrossFlowMF1.0 enables operators in many industries to achieve better control when finer filtration is desired without the necessity of using the more expensive membrane technology.

Used in combination, the CrossflowMF1.0 can effectively reduce a membrane's running costs and make significant operational efficiencies through the pre-removal of solid loading. In doing so, this increases the more expensive membrane's operational life and reduces cleaning frequency.