Water is a valuable resource - reuse and recycle it!
When water is cheap and abundant, the incentive to minimize waste and maximize recycling and reuse is low. But in many areas, water is becoming an increasingly scarce and valuable resource. Across the globe, many companies are taking greater efforts to recycle and reuse their industrial wastewater, motivated by factors such as water scarcity, social license to operate, local regulation and commitment to the Sustainable Development Goals (SDG). This shift from linear to circular water consumption which will only grow in the coming years. Learn how you can join the water revolution and increase the reuse and recycling of your industrial wastewater.
Wastewater reuse vs wastewater recycling – what is the difference?
When discussing industrial wastewater treatment, the terms “wastewater reuse” and “wastewater recycling” are often interchangeable (this also goes for water reclamation). For the sake of clarity, Aquaporin makes the following distinction when discussing wastewater recycling and reuse:
- Wastewater reuse is the treatment and purification of industrial effluent, thereby achieving a sufficient quality for subsequent use in different processes or for other purposes like irrigation, either within the same site or off-site.
- Wastewater recycling is defined as the treatment and purification of industrial effluent which is then routed back for use in the same process, thus forming a closed loop.
The potential for recycling and reusing more water
It is estimated by AQUASTAT and the UN that 19 percent of the global freshwater resources are used for industry purposes. This figure is much higher for industrialized nations. In Europe, industry consumes more than half (54 percent) of the water. And the demand for water from the industrial sector is growing, leaving less water for other sectors and potentially contributing to increased water scarcity in water-stressed areas.
This development is far from certain, though. Many companies and industries have recognized the importance of securing their water supply and the risk water shortage can pose to their business. A growing number of companies are taking measures to reduce their dependence on water resources such as limiting their water use.
Reduced access to usable water, either through water stress, quality issues or local competition for available water can severely impact industrial operations and disrupt supply chains. Climate change can further accelerate water scarcity, prompting local governments to enact regulatory changes to water use and allocation, pricing and effluent discharge.
In addition, the increasing public focus on sustainability and corporate accountability puts additional pressure on corporations to limit their water use and increase recycling and reuse. In many cases, this is felt along the entire supply chain, as brands raise expectations for sustainable behavior from their suppliers.
From linear to circular water consumption
Currently, the dominant economic model is a linear economy where natural resources are harvested, used and then disposed. In a water context, water is withdrawn from natural water bodies such as rivers, lakes and groundwater reservoirs, used for production and the wastewater is then discharged back into the water ecosystem, either directly or via effluent treatment facilities. In a linear economy, wastewater reuse or recycling is not a natural part of the production cycle, as wastewater reuse or recycling can be regarded as a cost-increasing add-on that is not essential for the process.
The linear consumption model is under increasing pressure, since it requires a continuous supply of fresh resources on the input side and generates significant quantities of waste that needs to be removed and managed. Frequently, this waste is hazardous to both people and environment and requires additional treatment. These constraints, which are enhanced by factors such as climate change, resource scarcity, regulatory policies and public awareness, illuminate the inherent flaws of the linear model and encourage the shift to a circular economy.
In a circular water consumption model, the reuse, recycling and recovery of water is a fundamental premise for the entire process. The main focus for the circular economic model is to minimize both material consumption and waste while extracting the maximal value from the resources that enter the cycle. For water resources, a circular water economy aims to reduce water consumption through more efficient wastewater treatment, which enables greater reuse and recycling of the wastewater and in many cases also the reclamation of other valuable resources from the wastewater, such as nutrients, salts and chemicals.
Drivers for increased reuse and recycling of industrial wastewater
Water scarcity
Water scarcity is one of the defining issues of the 21st century. Across the globe, water is becoming an increasingly scarce resource. According to World Resources Institute (WRI), one-quarter of the World's population face extremely high water stress. Several cities, including the industrial hub Chennai in India, Cape Town in South Africa and Rome in Italy, have experienced severe water shortages. This creates a strong incentive to minimize water waste and maximize recycling and reuse of industrial wastewater.
Increased regulatory demands
The rapid depletion of water resources and widespread pollution in many regions have forced local authorities to introduce regulations designed to improve wastewater recycling and reduce the discharge of contaminated industrial wastewater. In many cases, the use of zero liquid discharge (ZLD) or minimal liquid discharge (MLD) wastewater treatment processes have become mandatory. It is also important that any schemes for increasing water reuse and recycling are fully compliant with all regulatory requirements.
Pressure from consumers, customers and NGOs
With the growing focus on sustainability, conservation of resources and responsible production, factories are under increasing pressure to reuse and recycle their industrial wastewater. Local communities, NGOs and consumers all demand more sustainable production methods, more efficient reuse of water, and less wastewater discharge.
Commitment to SDGs
The UN’s Sustainable Development Goals (SDGs) are among the world’s most iconic and powerful drivers of innovation. In particular, the focus of SDG 6 is to ensure access to clean water and sanitation for all by 2030. From an industrial perspective, investments in technology to reuse and recycling wastewater contribute to a more responsible and sustainable use of local water resources.
Challenges with industrial wastewater recycling and reuse
Lack of incentive
One of the main barriers for increased recycling of industrial wastewater is simply that it is often easier to do nothing and maintain the status quo. In many areas, low cost of fresh water is a crucial factor for lack of incentive. The same applies if there are no or low costs to discharge untreated wastewater to either sewers or local waterbodies. If a mindset of pursuing water reuse and recycling is not ingrained in your organization, someone needs to push that agenda. This makes securing leadership support and sponsorship a priority when attempting to implement new processes for wastewater recycling. In Denmark, water costs are high both in and out, which is a strong incentive to save water. This is why so many water saving and recycling technologies are developed in Denmark.
Complex effluent composition
Most industrial processes create complex wastewater streams, which vary greatly in composition and are usually difficult to treat. Some have high levels of organic or biological compounds such as humic acid or algae, while others contain active ingredients from pharmaceutical manufacturing, Glauber's salt (sodium sulfate decahydrate) from textile production, or heavy metals like nickel and copper from the semiconductor industry. Factors like elevated biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and total dissolved solids (TDS), as well as the presence of suspended solids, cause scaling or fouling of the equipment and numerous other problems. As many industrial processes are quality critical, cleaning wastewater to a sufficient quality for reuse can be a challenge.
High CAPEX and OPEX
The inherent complexity means that industrial wastewater management and recycling usually involves significant capital expenditure (CAPEX) for the factory. Stricter requirements for effluent treatment in turn create the need to invest in technology such as ZLD, which increases operating expenditure (OPEX) as energy-intensive thermal evaporators are usually needed to remove water from the effluent.
Limited land availability
Increased expenditure resulting from new wastewater treatment solutions is not the only challenge that industries face. Because industrial areas are often already at capacity, especially in densely populated regions, the physical space available for new greenfield projects, or for the expansion or rearrangement of existing facilities, is limited at best. This makes it imperative for factories to simplify their treatment processes and optimize land use.
Strategies for increased recycling of industrial wastewater
Reduce waste and leaks
While not directly contributing to increased wastewater recycling, constant efforts to detect and prevent water waste and leakage from your water system will contribute to reducing your overall water consumption and limit the strain on water resources. Another way to minimize water consumption is to use more water efficient technologies in your industrial processes. This goes hand in hand with detecting and preventing leakages.
Optimize water processes
It is important to have a coherent planning approach to industrial wastewater reuse and recycling. Reuse and recycling should be included alongside other water sources for meeting water demands. It may be sensible to adopt a modular approach that makes it possible to adjust the capacity if the demand changes. In some cases, it is even possible to expand water reuse in industrial ecosystems, where treated wastewater from one enterprise is used as a resource by other enterprises.
Treat your wastewater at the source
In many industrial processes, effluent from different processes can have vastly different compositions, with some being much more difficult to treat than others. If these effluent streams are combined before treatment, it increases the total difficulty for removing unwanted compounds. This is known as the Cocktail Effect. Some of these pollutants can have a negative impact on the other pollutants making it more difficult to treat than if they were separated. Because of this, it is often worth separating these effluent streams and applying treatment individually, thereby greatly reducing the volume of problematic wastewater that needs to be treated.
Forward and reverse osmosis membrane filtration
For complex wastewater streams, membrane filtration using forward osmosis or reverse osmosis can provide the additional purification needed to reach the water quality that makes the wastewater suitable for reuse and recycling. The Aquaporin Inside® membrane technology developed by Aquaporin can significantly improve efficiency of industrial wastewater treatment, creating opportunities to reuse and recycle more water, reduce energy consumption, and decrease disposal costs. Forward osmosis using Aquaporin Inside® enables the efficient extraction of water, leaving behind challenging contaminants and reducing effluent volume. This leaves a greater quantity of purified water available for reuse while at the same time reducing the amount of energy needed to evaporate the effluent through ZLD.
Uses for recycled industrial wastewater
Industrial wastewater reuse and recycling can contribute to meeting the water needs several different processes, such as:
- Water cooling e.g., in cooling towers
- Rinsing and cleaning
- Process water
- Aggregate washing
- Dust control
- Agriculture e.g., irrigation of food and non-food crops
Want to know more about industrial water?
Go to our industrial hub to learn more about industrial water and how to treat it.
