Growing the portfolio: circular economy through water … – Frontiers

Reconciling Water Development and Management

In Iran, water scarcity is increasing due to the rapid growth in economy and population, as well as waste and overuse. Marginal water resources – unutilized water of lower quality – can provide important options to augment water supply or replace freshwater use. In this way, they can reconcile the seemingly opposing views of water development and water management. Encouraging the reuse and circulation of marginal water can enhance water availability and conserve vulnerable freshwater resources.

This paper analyzes water reuse options and policies in Iran. It explains policy constraints based on the type of water for reuse and compares the water reuse policies in Iran to regional experiences. Such a contextualization of Iran’s policies from a regional perspective provides opportunities for mutual learning and lessons for policy reforms. For Iran, there is a need for investments and comprehensive reuse policies. New water sources need to be appropriately identified, treated, delivered, and accepted by end-users and society.

The Imperative of Water Reuse in Iran

The decrease in water resource availability and quality represents a key challenge for future development in Iran. Due to the rapid growth of the economy and the population, the per capita share of renewable water resources is expected to drop from over 1,700 cubic meters in 2014 to below 1,000 per capita per year by 2030, thus indicating conditions of water stress (FAO, 2019). Agriculture lies at the heart of the increase in water demand (around 92% of total water consumption) (FAO, 2019).

One way to provide additional water quantity is to adopt circular economy approaches through the reuse and regeneration of resources. In this sense, a circular water economy can be achieved through encouraging the utilization of neglected water sources that can be treated and (re)used. Unconventional water resources of marginal utilization (marginal water resources) should be considered as one part of the solution to the increasing scarcities and recurrent shortages.

Status of Water Reuse in Iran

Although some marginal water resources such as treated sewerage effluents are being increasingly used, mostly for non-edible agriculture (i.e., uses and products not directly for human consumption such as landscaping or forage cultivation), there are many other unused resources and unexplored use purposes. The (re)use of marginal water resources in Iran is beginning to materialize but is still far from its full potential.

Wastewater Reuse

In 2015, there were around 150 municipal water and wastewater plants covering 23 million inhabitants, with the municipal and rural wastewater produced estimated at around 5 billion cubic meters by 2021 (Charkhestani et al., 2016). However, the official figures show that only around 1.33 billion cubic meters (74%) of this volume was treated in 2017. The number of wastewater treatment plants in 2017 was nearly 5 times higher than in 2001, and another 109 plants are under construction. Still, wastewater treatment plants serve only about 27% of cities and 48.9% of the urban population in Iran.

The bulk of the treated wastewater is used for irrigation, landscaping, and forestry near urban areas. There is also some intentional groundwater recharge, where the plants release effluent to recharge brackish water aquifers, and the water is later used through springs and qanats by farmers downstream for irrigation purposes. However, the unsystematic or spontaneous (unintentional) use of treated wastewater is estimated to be much higher, around 90% of the treated volume.

Other Marginal Water Sources

Besides wastewater, Iran has significant potential for utilizing other types of marginal water resources, such as:

• Agricultural drainage water: Estimated at around 30 billion cubic meters by 2021, this can be used in conventional or saline agriculture, for livestock, or to sustain wetlands.
• Saline water: The Caspian Sea’s water is diluted by freshwater inflows, with a salt concentration one-third of open seawater, providing opportunities for aquaculture and saline agriculture.
• Stormwater and rainwater: These sources have not been systematically explored for reuse, especially in major urban areas.
• Produced water: Iran is a significant producer of oil and gas, and the associated produced water is a potentially valuable marginal resource, if adequately treated.

However, the use of these other marginal water sources remains limited, and policies have primarily focused on municipal wastewater reuse.

Policies and Opportunities for Water Reuse in Iran

Policy Constraints and Challenges

Despite the apparent need for water reuse in Iran, several policy constraints and challenges exist:

1. Lack of infrastructure and monitoring: The coverage of wastewater treatment plants is still low, and there is a lack of infrastructure to collect, treat, and deliver marginal water to end-users.
2. Regulatory barriers: There is a need for clear guidelines and quality standards for the construction and operation of wastewater treatment plants, as well as for the different uses of marginal water.
3. Institutional coordination: Multiple agencies are involved in water reuse issues, with no clear national guidance for mainstreaming roles and enhancing cooperation.
4. Public acceptance: Concerns about the quality and safety of reused water, especially for food production, require education and awareness campaigns to build public trust.
5. Economic incentives: Low freshwater prices make it difficult to make water reuse economically viable, especially for agricultural users.

Opportunities from Regional Experiences

Comparing Iran’s water reuse policies with regional experiences can provide valuable lessons for policy reforms:

1. Technological advancement: The Gulf Cooperation Council (GCC) countries have promoted the wastewater reuse industry through ambitious government goals, using more advanced treatment technologies and infrastructure for aquifer recharge and agricultural use.
2. Integrated reuse systems: Jordan has developed an extensive network of canals and dams to transport treated wastewater directly to irrigation schemes, replacing freshwater use through agreements with agricultural user associations.
3. Diversified reuse options: GCC countries are also exploring the use of saline water for aquaculture and combined marine-terrestrial agriculture, providing examples of how to expand the portfolio of marginal water utilization.

Toward a Comprehensive Water Reuse Strategy in Iran

To grow the portfolio of water reuse in Iran, a comprehensive strategy is needed that addresses the various policy constraints and learns from regional experiences:

1. Invest in infrastructure and monitoring: Expand the coverage and capacity of wastewater treatment plants, develop distribution networks to connect treatment sites with end-users, and establish robust monitoring systems to ensure water quality.
2. Establish regulatory frameworks: Develop clear guidelines and standards for the construction, operation, and use of marginal water resources, with a focus on protecting public health and the environment.
3. Enhance institutional coordination: Clarify the roles and responsibilities of different agencies involved in water reuse, fostering collaboration and knowledge-sharing to streamline policy implementation.
4. Promote public acceptance: Conduct education and awareness campaigns to build trust in the safety and benefits of using treated and marginal water, particularly for agricultural applications.
5. Provide economic incentives: Reform water pricing structures to make water reuse more economically viable, while considering subsidies or other support mechanisms to encourage adoption by end-users.
6. Diversify reuse options: Explore the utilization of a wider range of marginal water sources, such as agricultural drainage, saline water, stormwater, and produced water, in addition to municipal wastewater.
7. Integrate reuse systems: Develop holistic approaches that link treatment plants with end-users, optimizing water quality for specific applications and leveraging the benefits of nutrient and energy recovery.

By implementing a comprehensive water reuse strategy, Iran can enhance water security, conserve vulnerable freshwater resources, and transition toward a more circular water economy. Embracing the diversity of marginal water sources and integrating reuse systems can help reconcile the competing demands for water development and sustainable management, securing a resilient water future for the country.

Conclusion

Promoting the circular economy through water reuse in Iran can alleviate major concerns related to increasing incidents of water resources overuse and depletion. Reused water can augment supplies or replace vulnerable freshwater resources, ultimately leading to a decoupling of agriculture production from water depletion. However, to fully realize this potential, Iran needs to invest in comprehensive water reuse policies that cover different types of marginal water sources, address regulatory and institutional barriers, and foster public acceptance and economic incentives. By learning from regional experiences and adopting a holistic approach, Iran can grow its portfolio of water reuse options and transition toward a more sustainable, circular water future.