Another OA Ambassador Spotlight Blog has landed!

Our OA Ambassadors raise awareness in their local communities about global OA movements as well as related opportunities through IWA Publishing. They are representatives of both the International Water Association and IWA Publishing and our joint goals to empower the next generation of water leaders and to shape the future of the water sector. These blog posts highlight their specialty and research focus, as well as emphasising the importance of Open Access publishing. 

Ibrahim Muntaqa Tijjani Usman is a Civil Engineering Ph.D. student with degrees in Water and Environmental Engineering, and Irrigation Engineering. His research is particularly focussed on nature-based solutions and the circularity of water. Connect with Ibrahim on LinkedIn!

Among the fundamental human rights is access to clean drinking water, but millions around the world still lack this basic necessity. The conventional water treatment systems face challenges in cost, energy consumption, and environmental impact. Engineers and scientists are turning to nature-based solutions for sustainable and efficient water treatment. This spotlight blog will highlight recent advances in nature-based solutions that hold promise for revolutionizing water treatment, protecting public health, and preserving the environment.

Constructed Wetlands

Natural wetlands treat wastewater effectively and naturally. Constructed wetlands mimic natural wetland ecosystems. They utilize the combined power of plants, microorganisms, and the physical environment to remove pollutants from wastewater. Constructed wetlands are a good alternative for wastewater treatment. They have low operations and maintenance costs, they are aesthetically more pleasing, and they are environmentally friendly. Recent advancements in constructed wetland design and operation have enhanced their performance, making them a viable and cost-effective option for decentralized wastewater treatment around the world. The workability of a constructed wetland can be seen in Coppini et al. (2019) research on the “Design and start-up of a constructed wetland as tertiary treatment for landfill leachates”. Despite mechanical and hydraulic malfunctions, a significant removal of COD at 10 gCOD/d.m2 was recorded.


The biodegradation of pollutants by microorganisms is the working principle of biofiltration, rather than physical removal by filter media as in regular filters. Using biological filtration media such as sand, or biofilm carriers, biofiltration systems effectively eliminate a wide range of contaminants, including organic compounds, heavy metals, and pathogens. Ongoing research focuses on optimizing biofiltration processes, improving contaminant removal efficiency, and exploring novel biofilter media for enhanced wastewater treatment performance.

Blue-Green Systems

Blue-Green Systems (BGS) refers to the integration of natural elements, such as trees, vegetation, and permeable surfaces, into urban environments to manage stormwater and improve water quality. Nature-based solutions like green roofs, rain gardens, and permeable pavements not only reduce stormwater runoff but also function as filters, removing pollutants and replenishing groundwater. One recent development in the Blue-Green infrastructure is the Sustainable Urban Drainage System (SUDS), which mimics the drainage patterns of the natural watershed, providing treated water with an acceptable level of quality for discharge. These innovative techniques promote sustainable water management and mitigate the impact of urbanization on water resources. Despite their increasing implementation, BGS do not always function perfectly. More research is needed towards mitigating the socio-institutional causes of BGS failures.

Solar Water Disinfection

Sunlight can disinfect water via two mechanisms: radiation in the spectrum of UV-A with a wavelength range of 320-400 nm, and rising water temperature. Solar water disinfection, also known as SODIS, is a simple and low-cost method that utilizes sunlight to disactivate harmful microorganisms in water. By exposing water to direct sunlight in transparent containers for a certain period of time (around 6 hours), SODIS effectively kills pathogens, providing safe drinking water in resource-limited settings. Recent advancements have explored the use of solar nanomaterials and improved SODIS implementation strategies, making this nature-based solution even more efficient and accessible.

Plant-Based Natural Coagulants

Coagulation and flocculation play a vital role in water treatment. There is more to chemical pretreatment before filtration than the physical facilities at the water treatment plant. Chemical-based coagulants are commonly used but can have adverse health and environmental effects. Toxic sludges and the presence of neurodegenerative disease-associated compounds are concerns. To address these drawbacks, plant-based coagulants have re-emerged as nature-based alternatives. Plant-based coagulants offer advantages such as low cost, availability, biodegradability, and biocompatibility. They help achieve safer drinking water, promote a cleaner environment, and support circularity in water treatment. The re-optimization of these natural coagulants is crucial for their effective use. By reducing the reliance on chemical coagulants, we can mitigate potential health risks, reduce treatment costs, and contribute to sustainable water management.

Anaerobic Digestion

Anaerobic digestion (AD) is a dual-benefit process that catalyses biofuel production and wastewater treatment. Utilizing bacteria in the absence of oxygen, AD breaks down organic matter in wastewater to produce biogas, a renewable energy source rich in methane. This reduces organic pollutants, pathogens, and greenhouse gases, promoting cleaner water discharge and mitigating climate change. Anaerobic digestion's economic viability makes it an attractive long-term solution for biofuel production and wastewater treatment, aligning with the focus on renewable energy and sustainable wastewater management. Anaerobic digestion could be a game changer in achieving the latter.

Nature-based solutions are transformative approaches for water treatment, including constructed wetlands, biofiltration, and blue-green systems for decentralized and eco-friendly wastewater treatment. Solar water disinfection offers a simple, low-cost method to purify water using sunlight. Plant-based natural coagulants are safe and sustainable alternatives to chemical coagulants. Anaerobic digestion benefits biofuel production, wastewater treatment, and climate change mitigation. Embracing these solutions is vital for a greener, healthier, and more sustainable water treatment future.


Ester Coppini, Laura Palli, Alexandra Antal, Massimo Del Bubba, Elisangela Miceli, Renato Fani, Donatella Fibbi; Design and start-up of a constructed wetland as tertiary treatment for landfill leachates. Water Sci Technol 1 January 2019; 79 (1): 145–155

Avery L. Carlson, Huanqi He, Cheng Yang, Glen T. Daigger; Comparison of hybrid membrane aerated biofilm reactor (MABR)/suspended growth and conventional biological nutrient removal processes. Water Sci Technol 15 March 2021; 83 (6): 1418–1428

Elhadi Mohsen Hassan Abdalla, Ingrid Selseth, Tone Merete Muthanna, Herman Helness, Knut Alfredsen, Terje Gaarden, Edvard Sivertsen; Hydrological performance of lined permeable pavements in Norway. Blue-Green Systems 1 January 2021; 3 (1): 107–118

Vita Vollaers, Eva Nieuwenhuis, Frans van de Ven, Jeroen Langeveld; Root causes of failures in sustainable urban drainage systems (SUDS): an exploratory study in 11 municipalities in The Netherlands. Blue-Green Systems 1 January 2021; 3 (1): 31–48

Nilanjana Das, Nupur Ojha, Sanjeeb Kumar Mandal; Wastewater treatment using plant-derived bioflocculants: green chemistry approach for safe environment. Water Sci Technol 15 April 2021; 83 (8): 1797–1812

Siong-Chin Chua, Pau Loke Show, Fai-Kait Chong, Yeek-Chia Ho, Lentil waste as novel natural coagulant for agricultural wastewater treatment. Water Sci Technol 1 November 2020; 82 (9): 1833–1847

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