Today, severe droughts are driving substantial economic losses, hundreds of millions of people still lack reliable access to clean water, and many critical water resources are being depleted or contaminated. Solving these water challenges will take a variety of solutions, including recycled water.

In the past, municipalities have looked to increase water supply by finding new sources, like seawater desalination. The focus is now turning to the more efficient use of water through recycling and reuse.

Using proven technologies, water recycling and reuse produces high-quality water, often at a lower life-cycle cost than the development of new water supply options. New supply options can involve acquiring the rights to a new water source, drilling deeper wells, resizing pipe networks, and increased operating costs for pumping and treatment. Water recycling and reuse, on the other hand, provides a resilient and drought-proof water source that can drive social, environmental and economic benefits.

Changing public perception of recycled water

History shows that the water and wastewater sector is conservative by design and therefore slow to adopt new practices. Key concerns for the adoption of reuse have been public acceptance, regulatory requirements and financial capacity.

It seems, however, that public acceptance is changing. A recent survey conducted by Xylem in California showed that 76 percent of residents surveyed believe that recycled water should be used as a long-term solution, regardless of drought. Many countries have been discussing the need, and several initiatives have been started to encourage the adoption of water recycling and reuse.

Qatar has committed to increase reuse capacity by 24 percent over the next four years.  Saudi Arabia is planning to reuse 100 percent of water in large cities by 2025. Singapore plans to triple water reuse by 2060. The European Commission published the EU Circular Economy Strategy in late 2015, which consists of policy initiatives to shift from a consumption-based economy towards a recycling and reuse based economy. In China, the Water Pollution Prevention and Control Action Plan, Public-Private Partnership (PPP) financing and wastewater tariffs are also urging reuse.

The need for regulations on recycled water quality

Currently, the rules and regulations are limited around the necessary water quality for different recycling purposes. Some existing regulations were written years ago and need to be updated in a way that reflects the current water crisis, while also considering the technologies of today.

“At Xylem, we believe that national and local governments should work to harmonize these regulations and codes to allow for the use of recycled water for both non-potable and potable uses,” says Abigail Antolovich, Water Reuse Business Development Manager at Xylem. “In the US, California has been a leader in developing water reuse standards that are now being used as a model for other state regulatory developments.”

The growing needs for potable reuse and additional non-potable applications are driving the development and modifications of reuse regulations in many states across the US in order to address local issues and ultimately support a broader spectrum of reuse projects.

Different uses and treatment methods for recycled water

Recycled and reused water can be used for a variety of purposes in both homes and businesses including:

– Irrigation for food and non-food agriculture
– Urban irrigation of parks, residential lawns, golf courses, and other urban landscapes
– Industrial uses in cooling towers, cleaning of equipment, and process water
– Aquifer recharge through direct injection wells and indirect natural recharge
– Urban non-potable use in firefighting, road cleaning, and flushing toilets, and
– Direct potable reuse water.

Drought is not always the driving factor for reuse. “Xylem has a number of projects where drought issues are not a concern, such as Minnesota and Pennsylvania,” says Antolovich. “Utilities are starting to look at their water portfolio management and how to incorporate reuse into the overall supply strategy. Even if there has been plenty of water, some communities are facing increased competition for water supply, or restrictions on discharges due to environmentally sensitive areas, and are implementing reuse projects.”

There is often a perception that there is a “one size fits all” water reuse solution. Different quality standards are needed based on the planned use of the treated water, whether it is used in irrigation, for direct or indirect potable reuse, or to serve industries as a water source. There are many different types of treatment and treatment trains, and Xylem works with its customers to develop a solution that is “fit for purpose.”

For example, Xylem provided the process chain for a water reuse plant in Doha South, Qatar. It supplies up to 220,000 m³/day of recycled water. The process involves a Sanitaire ICEAS installation followed by a UF system. Xylem has another four reuse plants currently in construction in the Middle East, all based on the company’s ICEAS SBR technology, with further treatment processes including its Wedeco UV solution.

Advanced recycled water research and innovation

“Besides its own research, Xylem supports research for water reuse through partnerships with major research institutions,” says Christoph Kullmann, Director of Strategy for Xylem’s Treatment business. “These include the Swedish Environmental Institute (IVL), the Royal Institute of Technology (KTH), the Water Environment & Reuse Foundation, and the University of Arizona. These partnerships support Xylem’s innovation efforts, which have supported development of new, more effective and efficient reuse technologies.”

With the Swedish Environmental Institute (IVL), for example, Xylem studied eight different treatment systems based on water treatment technologies already available today. The systems were evaluated and optimized in pilot tests and at a number of full-scale plants around the world. The results of the study help show how to build and operate the most cost-efficient and sustainable reuse plants, depending on the plant’s size, level of water quality and a number of other factors. 

“For decades, Xylem has helped municipalities around the world give their precious water resources a second life, taking used water from municipal and industrial systems and helping to recycle it in homes, farmland, landscaping, and new industrial processes,” says Kullmann.

Flygt pumps and mixers, Sanitaire biological treatment systems, Leopold filters, UF membranes, Wedeco UV and ozone disinfection systems, and YSI analytic instrumentation are helping municipalities extract value from wastewater – while ensuring consumer safety, renewing the environment, and saving money.