The wastewater circular economy: an untapped resource

In recent years, the concept of a circular economy for wastewater has been gaining traction among policymakers, engineers and environmentalists. A circular economy model emphasises the shift from viewing wastewater as a nuisance to be disposed of to a valuable resource that, when managed judiciously, can play a pivotal role in fostering sustainable development.  

As populations flourish and natural resources dwindle, transitioning towards a circular economy approach for wastewater is not only environmentally prudent but also a pragmatic solution to some of the most pressing challenges of our times. Read on to explore how reimagining wastewater management can contribute to a circular economy, creating a ripple effect of benefits for our planet and its inhabitants. 


Transitioning to Circular Efficiency 

The traditional linear economy model follows a straightforward path: extract resources, manufacture goods, distribute them, and dispose of them post-consumption. This ‘take, make, and dispose’ system doesn’t leverage the full potential of our resources, hastening their depletion. It’s a path that leads to less land, polluted oceans, lost biodiversity, scarce freshwater, and fewer forests.  

The circular economy model, on the other hand, challenges this approach, focusing on extending a product’s lifespan through repairing, recycling, redesigning, and reusing or transforming back into the natural cycle, all while minimising the use of resources. Transitioning to this model is not just a surface change; it’s about diving deep to better design materials, products, systems, and even innovative business models. 

As a result of domestic, industrial, and commercial activities, wastewater shouldn’t be considered just an end product. It has the potential to be a kick-starter for a resourceful loop, ready to be circled back into our systems. More so, the shift towards a circular economy in wastewater can fuel a cycle of sustainable growth that addresses upcoming challenges facing humankind.

Population growth fuels wastewater crisis. 

As the world population experiences rapid growth, the volumes of wastewater generated are rising at a parallel rate. This increase is further propelled by improvements in water supply, elevated living standards, and economic development. Despite the rise in modern cities across the world, a shocking volume of global wastewater continues to be discharged into our environment, with only 11% being treated and reused.  

When we look at municipal wastewater, around 380 billion cubic meters of wastewater are generated globally each year, and nearly half of it enters the environment without any treatment. This underscores a significant issue: only a fraction of the total wastewater produced is collected, treated, and harnessed for resource recovery. Looking ahead, by 2050, nearly 10 billion individuals will inhabit our planet. This growth is anticipated to trigger a 51% increase in wastewater generation.  

A key macro-trend in this scenario is urbanisation. An additional 2.5 billion people will live in cities by 2030, placing different demands on municipalities and utilities that need to build new infrastructure or upgrade current systems. By tailoring their municipal infrastructure and systems for a circular economy, many cities can pave the way toward a sustainable urban landscape. 

The environmental and health implications of untreated wastewater are profound. Untreated wastewater leads to eutrophication (algal blooms) and deprives the waters of oxygen, decimating aquatic life. In addition, wastewater is a potent source of greenhouse gases, including methane, which alone contributes approximately 1.6% of global emissions as per UN data. This figure places wastewater emissions just below the climate impact caused by the global aviation industry.

Apart from the devastating effects on ecosystems, the lack of a circular approach for wastewater also greatly affects public health, as untreated wastewater hosts a wealth of pathogens that can reach communities via local water bodies. Towns that use natural rivers for drinking water and other domestic uses expose themselves to diarrhoeal diseases, such as typhoid fever, cholera, and rotavirus. It is almost unthinkable that, in this age, about 1000 children still die every day from unsafe water and poor hygiene and sanitation. Disease outbreaks and deaths due to untreated wastewater prevent many underdeveloped and developing nations from accessing the benefits of a healthy, productive workforce and burden healthcare systems.

The urgency to address wastewater issues is palpable today and will only escalate in the near future. 


Unlocking wastewater’s circular economy potential 

Fortunately, wastewater is a renewable resource within the hydrological cycle. Once utilised, it can be processed and reused again. Reusing wastewater is not only an ecological imperative but an economic necessity. As such, it’s crucial to reframe our perspective.  

If treated effectively, wastewater ceases to be a problem awaiting disposal. Instead, it morphs into a unique circular economy opportunity that can address critical challenges such as water scarcity, irrigation, additional energy generation via biogas production and fertiliser production via biosolids handling. By managing wastewater in a way that captures resources for sustainable reuse, we unlock its potential as a valuable resource. 

Treated wastewater offers a plethora of benefits. It can power alternative energy sources for up to half a billion people, substantially reducing CO2 emissions. Moreover, with appropriate handling, wastewater globally has the potential to irrigate close to 40 million hectares - an area larger than Norway. Furthermore, biosolids produced from sludge treatment in wastewater facilities can offset over 10% of global fertiliser use, decreasing pollution and emissions significantly. 

A recent analysis by the UN environmental program highlights these remarkable findings, revealing the untapped potential of wastewater as a holistic solution to climate and nature challenges. This analysis serves as a clarion call for clear and decisive action towards harnessing wastewater as a resource. 

Revolutionising municipal wastewater treatment globally 

What is unknown to many is that municipal wastewater treatment utilities are at a crucial turning point in history. Plenty of facilities around the world are using archaic technologies for wastewater treatment, struggling to keep up with increasing populations, and needing sounder economic strategies for sustainability.

A vital component of the solutions to these problems lies in the opportunities touted by the UN and other global institutions - renewable energy and soil products - the circular resources recovered from sludge or wastewater solids. In modern wastewater treatment facilities, sludge is separated from wastewater before water is further treated prior to release into the environment. Sludge is the source of biogas and fertiliser – often after several digestion and dewatering processes.

Simply put, to pivot and fully utilise wastewater in a circular economy is also to use sludge fully. To do this on a global scale, “more” is needed, and at a faster rate, just as is reiterated by the United Nations: more use of innovative technologies and solutions, more awareness and access to financing mechanisms, and more partnerships between all stakeholders.

It is then that we can change untreated wastewater from a liability to the crucial asset it truly is and uncover that wastewater is an integral part of a circular economy.

Cambi’s technology enables the circular management approach for municipal wastewater, essentially turning sludge into pathogen-free high-quality biosolids which can be recycled back to nature. Through our sustainable tech solutions, we’ve taken strides towards societal objectives, particularly emphasising circularity in wastewater management. 

Compared to conventional technologies, Cambi’s Thermal Hydrolysis Process (THP) technology amplifies biogas production, minimises digester volume by a third, slashes biosolids disposal volume by 50%, eradicates pathogens, eliminates odours, and boasts the lowest carbon footprint with the most cost-effective operation. This approach is emerging as the safest, most responsible choice for wastewater treatment plants serving towns to megacities. We play a significant role in the global transition to sustainable, smart and safe cities. 

Our mission extends to global cities, establishing this technology as the benchmark for wastewater solutions. We have a solid commitment to the millions of people benefiting from CambiTHP technology in our reference plants across 27 countries.

Learn more about Cambi’s commitment to solving the big picture for wastewater treatment in our Capital Markets Update.

30 October 2023


Anda Somodea

Anda Șomodea is the Marketing Director at Cambi. She has a passion for interesting technologies and using them to create strategies that connect the business with potential customers.
Anda Somodea, Marketing Director at Cambi
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