Turning the Tide with Wastewater: Nature Based Solutions for a Thirstier World

Water scarcity is forcing governments and industries to rethink how we manage one of our most overlooked resources: wastewater. Today, more than 80% of the world’s wastewater is still released untreated, a loss of both water and valuable nutrients that could be recovered instead.

Wastewater treatment has typically relied on energy intensive, centralised plants, with multiple mechanical and chemical stages. While highly effective, this infrastructure is expensive to build and power, and it often stops short of reclaiming water for reuse.

In recent years, a new generation of approaches based on biotechnology and nature has emerged. Some work inside compact reactors, using microbes, electrodes or algae to recover energy or nutrients from waste. Others work at the ecosystem scale, using wetlands or seaweed to clean water as part of a living system. Together, they point toward a future where wastewater becomes a resource rather than a liability.

Microbes at work

One way is to treat organic wastewater as not just a disposal problem, but as a source of recoverable energy. WASE does this by using microbes and electrodes to recover energy from organic waste streams. Its electro-methanogenic reactors grow electrically active bacteria on electrodes inside an anaerobic system. As organic material is broken down, electrons, hydrogen ions and carbon dioxide are channelled towards the cathode, where bacteria convert them into methane-rich biogas that can be used on site.

This is particularly relevant for brewers, distillers, dairies and food manufacturers, where wastewater often contains a high organic load and therefore a useful amount of recoverable energy. An excellent example is Hepworth Brewery in West Sussex, where WASE has integrated its system on site to treat around 17 m³ of brewery wastewater each day. Instead of paying to have that effluent hauled away, the brewery can turn it into biogas for a combined heat and power unit, generating renewable energy from its own waste stream.

The treatment system at Hepworth Brewery is expected to generate 362 MWh of net energy each year and avoid more than 100 tonnes of CO₂ emissions annually, demonstrating the practical and environmental benefits of this approach. Treated water is then polished through a reed bed before being returned to the local environment, while a nutrient-rich digestate can be used by local farmers. It is a neatly circular model: wastewater is treated where it arises, energy is recovered on site, and the remaining outputs are put back to productive use.

Wastewater into watts

Cambrian Innovation’s EcoVolt® system offers another route to energy-positive wastewater treatment. Inside the reactors, microorganisms consume organic pollutants and release electrons, which the system captures and redirects to support biogas production. This bioelectrically enhanced process boosts natural anaerobic digestion and helps turn high-strength industrial wastewater into usable energy.

The resulting biogas is fed into a combined heat-and-power unit, where it is converted into electricity. Depending on the site, this can produce anything from 30 to 400 kilowatts. By the time the water leaves the reactor, 80 to 90% of pollutants have been removed, making it suitable for uses such as irrigation or equipment washing. For some industries, the carbon savings are significant: a winery, for example, can cut roughly a kilogram of CO₂ per case of wine by generating its own clean energy.

Letting nature do the work

Not every innovation has to sit inside a reactor. Constructed wetlands are currently the most established nature based solution for wastewater.  These engineered systems mimic natural wetland functions, using a combination of wetland plants, substrates such as gravel or soil, and associated microbial communities to remove contaminants. As wastewater flows slowly through the wetland, sedimentation, filtration, plant uptake and microbial degradation progressively purify the water.

A growing body of evidence suggests that well designed constructed wetlands can reliably treat domestic and industrial effluents to standards suitable for water reuse, particularly for agriculture and industry. In addition, they also require less energy, and integrate better into the landscape than a traditional water treatment plant.

New regulations on river pollution and biodiversity, coupled with climate and net zero targets, are driving utilities and industrial players to incorporate wetlands in their treatment trains. In some cases, existing treatment ponds have been converted into hybrid lagoon–wetland systems, where plants and microorganisms finish the “polishing” of effluent before release or reuse. 

Microalgae, macro-impact

We have previously written about the many benefits of utilising algae. Industrial Phycology applies similar biological potential to wastewater treatment. Their technology builds on decades of research showing just how efficiently microalgae can strip out nutrients such as nitrogen and phosphorus from municipal and industrial effluents.

Inside Industrial Phycology’s reactors, dense algal communities are continuously fed by wastewater streams. As the algae bloom, they pull nutrients from the water, locking them into biomass while simultaneously releasing oxygen that fuels microbial breakdown of organic matter. The result is a compact, self-sustaining treatment step that reduces eutrophication risk downstream and captures carbon in the process.

Once harvested, the nutrient-rich biomass becomes a resource: it can be processed into fertilisers or soil enhancers, thereby effectively returning urban waste nutrients to agricultural systems. It’s a tight loop: pollution removed, carbon captured, and valuable materials recovered, all in one elegant biological cycle.

Seaweed solutions

While microalgae operate primarily in controlled reactors, seaweed can deliver a similar nutrient scavenging function at a far larger, landscape scale.  

Algapelago, a UK-based regenerative mariculture company, is developing seaweed systems that act both as productive farms and as living coastal infrastructure. Their approach offers a double benefit. As the seaweed grows, it naturally draws in dissolved nitrogen, phosphorus and carbon from the surrounding water. This helps to curb nutrient pollution from land based sources such as agriculture and aquaculture. In effect, each farm becomes a biological filter woven into the coastline, improving water quality while steadily producing harvestable biomass.

Algapelago can also process the harvested seaweed into low-carbon animal feed supplements and plant fertilisers. That gives the harvested biomass a further use, with nutrients taken up at sea finding their way back into sustainable agriculture.

Catching forever chemicals

Some contaminants present a different challenge from nutrient-rich or organic wastewater streams: they persist, travel through water systems, and are difficult to remove using biological treatment alone. PFAS are the clearest example. Often described as “forever chemicals”, they can resist breakdown and pass through conventional treatment processes, creating an urgent need for better capture materials before treated water is released or reused.

Pure Capture Innovations is tackling this problem at the filtration stage. It is developing sustainable adsorbent materials for water purification, including biochar-based filter composites aimed at short-chain PFAS and other micropollutants. The practical appeal is that these materials are intended to work as drop-in replacements for activated carbon, improving contaminant capture without requiring a wholesale redesign of existing infrastructure. In other words, existing treatment plants could become much better equipped to deal with a new generation of hard-to-remove chemicals.

Designing with nature for a drier future

Water scarcity is, at root, a design problem. It is the result of infrastructure and systems built on the assumption of abundant, cheap freshwater and limitless sinks for pollution. The examples above show a different direction: treatment systems that recover energy, reuse nutrients, clean water biologically and capture pollutants that older infrastructure was not designed to handle.

Microbial reactors that turn organics into energy, constructed wetlands that mimic natural filtration, microalgae systems that harvest nutrients, seaweed farms that clean coastal waters and new adsorbents that capture persistent contaminants all point in the same direction: a future where wastewater is recognised as a valuable material stream.

As companies like WASE, Cambrian Innovation, Industrial Phycology, Algapelago and Pure Capture Innovations demonstrate, many of the most promising ideas sit at the interface between engineering and ecology. Protecting those ideas, and the data and know how that support them, will be a crucial part of scaling solutions that can help society adapt to a hotter, drier, more resource constrained world.

Nathan Zhang, Associate and Patent Attorney at Mewburn Ellis, comments:

“The common theme running through these technologies is the move from waste management to resource recovery.  It’s not simply removing pollutants, but also recovering nutrients, harnessing energy, and creating valuable downstream products.  That shift may fundamentally change how wastewater infrastructure, from reactor configurations to treatment processes, is designed.  Protecting these innovations will help innovators capture the value of this transition."