Technology revolution that can take on climate change impact
David Garman, president of the International Water Association and executive director of the Environmental Biotechnology Cooperative Research Centre in Australia, looks at trends and future directions in water technology
As climate change and urbanisation put a strain on global fresh water resources, water utilities are increasingly moving to exploiting poorer quality water sources - desalination - and incorporating high levels of recycled water. Such changes are posing many challenges, as not only are these sources more energy intensive, they are also more expensive to treat.
Most of the new technologies in the water industry have been around for about 20 or 30 years - sometimes more. While there are continuing improvements in technologies such as membranes, microbial fuel cells, nutrient removal, new SCADA systems or leak detection technologies, they are often not new. In many cases these changes have been incremental rather than fundamental.
For example, developments in membrane technology have been the most widely adopted in water and wastewater treatment, with the greatest impact. Since the early days there have been overall efficiency improvements probably of an order of nearly ten, and cost reductions of a similar order.
Current challenges expand from energy use in membrane-based desalination and wastewater processes, to the management of trace organics and micronutrients.
It is in these areas that many novel technologies will provide breakthrough solutions beyond those incremental changes normally associated with new technology. The increased adoption of biotechnologies and nanotechnologies as standard tools other than in the water treatment business is also making them more widely available and cost effective.
The pressures on water utilities worldwide are increasing as impacts attributed to global warming take effect. The effects include an apparent increasingly unreliable rainfall, as well as more extreme periods of drought and flood. These, coupled with growth in urbanisation, are placing utilities in difficult positions, with calls for new efficiencies and pressures on all aspects of management and operations.
The changes have had two major impacts - new water sources have to be accessed, often of poorer quality, and where freshwater options do not exist, non-traditional sources such as stormwater, recycling and desalination are increasingly being accessed. In most cases the use of traditional water treatment processes alone - such as coagulation and filtration - are no longer appropriate.
Sustainability has also become increasingly important for leading-edge utilities. The questions of increased energy costs and the potential impacts of greenhouse gas accounting are leading to other considerations. The energy used for pumping, high-pressure treatment systems, and long pipelines - with associated pressure losses - have focused some water authorities to put more effort into sustainability management, including energy reduction.
New technologies will be required to provide options and opportunities for water managers to cope with these global and local changes.
There will continue to be incremental improvements in all areas of the water treatment, distribution and management systems.
In the short term there will be application and use of improved technologies for existing processes such as digestion of organic wastes or biosolids, improved biological nutrient removal techniques, lower energy membranes and energy recovery.
Innovation is taking place across all areas from materials to flow detection, measurement and leakage control, through to water and wastewater treatment, biosolids handling and trace chemicals detection. For example, in some cases, improvements in information technology have led to significant improvements in water monitoring and water-loss reduction. There is also a tendency to increasingly adopt combinations of technologies, rather than single solutions.
I foresee that in the near future some recent innovations will become more rapidly adopted as the pressures on utilities increase. Some of the potential technological changes that are emerging are largely coming from outside the traditional areas of water and wastewater treatment. They will provide solutions to some of the big challenges that have been put out by various organisations, by:
- Halving the energy required for desalinisation
- Stopping micro-contaminants continuing to pollute water systems
- Recovery of nutrients from used water
- Rapid detection of microbial contaminants
- Low-cost efficient sanitation systems
Some technologies that I believe will be the next generation include:
- Granular sludges for wastewater treatment
- Nanomaterials for contaminant removal - concentration and oxidation, and resource recovery, including nutrients
- Rapid molecular-based pathogen detection technologies
- New materials for membranes and membrane operations Some of the novel applications include targeted removal of biofilms, pathogenic organisms and trace organics using biomimicry and model structures that resemble natural removal processes. These will replace the bulk oxidation processes that are in use today, using smart nanomaterials instead of traditional flocculation and filtration processes.
Use of nanomaterials for improved oxidation is already proven in areas outside the water industry. It is only a matter of time before they are introduced, with potential to use visible light, instead of UV, for disinfection and contaminant removal.
Other applications include the development of molecular methods that will supplant culturing procedures for microbial assessment. This will mean the speed of analysis will decrease to less than 30 minutes - in the field. New control methods based on molecular methods should also improve the management and specific process operations. This will allow faster and better water recycling for potable operations.
Molecular methods in microbiology are leading to new processes in wastewater treatment ranging from granulation of aerobic sludges through to improved removal of nutrients. The ability to use granules - or solid flocs, at MLSS concentrations (6,000-8,000mg MMSL/L) used in MBRs - and then being able to settle these in under four minutes, could completely change the wastewater treatment industry.
Couple that with an ability to dry the granules to >40% solids in minutes without additional technology and you have a revolution in technology.
Microbial fuel cells are a hot topic at present and there are increasingly significant improvements in power outputs that have been recorded. So will we see this in the water industry? The most likely applications are in the treatment of high-strength wastes from industry. The weak strength of domestic wastewater means this is a less likely application for this technology - unless water recovery is practiced and the organic component is increased.
So, how long will it take to introduce these new technologies? While it took about 30 years for membranes to be widely adopted, I estimate some of these newer technologies will be in place in less than five years, certainly in ten years. We have already ten years of R&D behind us which will lead to some of the new innovations emerging rapidly.
Industry needs are the driving force of new development. The uptake of anaerobic digestion processes for sludges and the Annamox process are examples where the industry need has driven a faster uptake of a new process. More general pressures such as the need for energy efficiency, reduction in greenhouse gases and improvement of operational efficiencies will drive the adoption of new, cleaner technology.
One of the challenges for management and operations is the integration of traditional technologies with new ones. This is not only a design and specification problem - it also requires a significant upskilling of the workforce at all levels. This is from specifications engineers, to designers, through to operators and maintenance.
This selection of emerging technologies is not exhaustive. I hope they give an indication of the changes and technologies that are emerging across the water and wastewater industries. The challenge today is to make them all accessible - in every sense of the word.