Showing posts sorted by date for query WASTEWATER. Sort by relevance Show all posts
Showing posts sorted by date for query WASTEWATER. Sort by relevance Show all posts

Tuesday, April 28, 2026

 

Efficient degradation of short-chain PFAS



UFZ team develops new method to remove perfluorobutanoic acid from water





Helmholtz Centre for Environmental Research - UFZ

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Researchers at the UFZ have developed an environmentally friendly, efficient process for removing short-chain PFAS from water. During this process, the PFAS are first separated and concentrated by electrosorption (Step 1) and then destroyed by electrooxidation (Step 2). The main byproducts are CO2 and fluoride.

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Credit: UFZ





About 10,000 PFAS substances are currently known, of which 4,000–5,000 are used in industry, including in the production of outdoor clothing, food packaging, cookware, and cosmetics. Numerous PFAS – such as those found in firefighting foams – enter the environment and degrade only very slowly if at all. Because they pose a risk to human health by affecting metabolism, hormone balance, reproduction, and the immune system and are suspected of being carcinogenic, many long-chain PFAS have been regulated under the Stockholm Convention. Their production and use are now prohibited or restricted. In response, they have been increasingly replaced with short-chain PFAS. As a result, compounds such as perfluorobutanoic acid (PFBA) are being detected more frequently in the environment. With only four carbon atoms and a carboxyl group at one end of the molecule, PFBA strongly attracts water. “That is why PFBA dissolves readily in water and is highly mobile. It is therefore difficult to remove PFBA from water using conventional methods such as activated carbon adsorption”, says Dr Anett Georgi, UFZ chemist and co-author.

To remove PFBA from water, the UFZ research team has developed a two-stage electrochemical purification process in which PFBA is first concentrated and then broken down. How it works: In the first step, large volumes of PFBA-containing water are passed through a flow cell with an electrode made of a textile-like activated carbon fibre felt; this electrode is given a slight positive charge for electro-adsorption. “This causes the negatively charged PFBA to accumulate on the surface of the activated carbon”, says Dr Navid Saeidi, UFZ environmental engineer and lead author. By reversing the polarity of the voltage, the PFBA is then detached from the surface, rinsed away with a small volume of water, and collected as a concentrate. This can increase the PFBA concentration by a factor of 40. By arranging the electro-sorption cells in a cascade configuration, this enrichment process can be repeated several times. In the second step, PFBA is broken down by electro-oxidation at a boron-doped diamond electrode (i.e. through a chemical purification of the water triggered by an electric current). The anode has a strong oxidising effect and causes PFBA to decompose. The main by-product is fluoride, which is easily separated.

“All steps can be carried out on site, thereby reducing transport costs and energy requirements”, says Georgi. Because PFBA adsorption is controlled by applying an electrical voltage, the activated carbon material can be regenerated repeatedly and reused multiple times – unlike other processes in which PFAS-contaminated activated carbon must be disposed of in waste incineration plants or regenerated with high energy input. “This not only conserves fossil resources but also reduces CO2 emissions because activated carbon is often produced from hard coal and is mainly imported from Asia”, says Georgi.

The UFZ scientists have already filed a patent for this process because they see many potential applications, particularly in removing PFAS from municipal and industrial wastewater streams, including at airports, where groundwater is contaminated with short- and long-chain PFAS as a result of the use of firefighting foam. “In light of the increasingly stringent PFAS limits that operators are required to comply with, there is a need for more efficient removal technologies that are as reliable, environmentally friendly, and affordable as our method. It could complement traditional activated carbon adsorbers in cases of complex PFAS contamination and capture short-chain PFAS”, says Dr Katrin Mackenzie, UFZ chemist and co-author. This would result in a considerably longer service life for the entire adsorber unit and thus lead to cost savings.

Monday, April 27, 2026

Biochar-powered hydrogels boost solar water evaporation efficiency for sustainable desalination




Biochar Editorial Office, Shenyang Agricultural University
Heat loss and water transport capacity regulation in hybrid evaporators 

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Heat loss and water transport capacity regulation in hybrid evaporators

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Credit: Sihui Wang, Jiaqi Yang, Aijie Wang & Wenzong Liu





A new study reveals how combining biochar with advanced hydrogels can dramatically improve solar-driven water evaporation, offering a promising pathway for low-energy desalination and water purification technologies.

Freshwater scarcity is a growing global challenge, with most of Earth’s water locked in oceans or saline sources. Traditional desalination methods often require high energy input and infrastructure costs. Solar interfacial evaporation, which uses sunlight to convert water into vapor at the surface, has emerged as a cleaner and more energy-efficient alternative. However, improving its efficiency remains a key scientific challenge.

In a recent study published in Biochar, researchers developed a hybrid material that integrates biochar into a polyzwitterionic hydrogel, achieving a remarkable evaporation rate of 3.57 kilograms per square meter per hour under standard sunlight conditions. This performance is significantly higher than that of conventional hydrogels and highlights the potential of biochar-based materials in sustainable water treatment.

“By introducing biochar into the hydrogel network, we were able to simultaneously enhance light absorption, water transport, and energy efficiency,” said the study’s corresponding author. “This multi-functional synergy is key to achieving high-performance solar evaporation.”

The innovation lies in how biochar interacts with the hydrogel at both physical and molecular levels. Biochar, a carbon-rich material derived from biomass such as agricultural waste, is known for its porous structure and strong light-absorbing properties. When incorporated into the hydrogel, it transforms the material from transparent to dark, enabling it to capture more sunlight across a wide spectrum. According to experimental results, the hybrid hydrogel maintained over 95 percent light absorption across a broad wavelength range.

At the same time, the addition of biochar alters the internal structure of the hydrogel. Microscopic observations, shown in figures on page 4 of the paper, reveal a denser and more interconnected pore network. This structure improves the movement of water within the material, ensuring a continuous supply of water to the evaporation surface while minimizing heat loss to the bulk liquid.

Beyond photothermal effects, the study also uncovers a less explored mechanism involving water molecule behavior. The surface functional groups of biochar interact with the hydrogen bonding network inside the hydrogel, increasing the proportion of so-called intermediate water. This form of water requires less energy to evaporate compared to tightly bound water. As a result, the hybrid material significantly reduces the energy needed for evaporation, lowering the equivalent evaporation enthalpy to 877.79 joules per gram.

This dual enhancement, combining photothermal efficiency with molecular-level water activation, enables the hybrid hydrogel to outperform many existing materials. The system also demonstrates strong water transport capabilities even in saline conditions, making it particularly suitable for seawater desalination applications.

The researchers emphasize that biochar is not only effective but also sustainable and cost-efficient, as it can be produced from agricultural residues such as sorghum straw. This adds an important environmental advantage, aligning the technology with circular economy principles.

“Our findings provide new insights into how material design can address multiple bottlenecks in solar evaporation systems,” the authors noted. “This could guide the development of next-generation evaporators for clean water production in resource-limited settings.”

As global demand for freshwater continues to rise, innovations like biochar-enhanced hydrogels could play a critical role in delivering scalable, low-carbon water treatment solutions.

 

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Journal Reference: Wang, S., Yang, J., Wang, A. et al. Heat loss and water transport capacity regulation in hybrid evaporators. Biochar 8, 97 (2026).   

https://doi.org/10.1007/s42773-026-00604-0  

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About Biochar

Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field. 

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Paying the Piper

Ballast discharge
USDA file image

Published Apr 23, 2026 8:16 PM by Paul Benecki

(Article originally published in Jan/Feb 2026 edition.)

 

The average merchant ship has a service life of 20-25 years, in some cases more. That's a long time to stay in compliance with all the rules that govern shipping, and owners know they have to set themselves up for success.

It's not enough to meet regulations on day one: Every ship system has to be supported throughout a lifetime of industrial service if it's going to satisfy inspectors on day 5,000. Without solid backing from the original equipment manufacturer (OEM), any complex system becomes difficult to maintain – a reality that's coming home to roost for owners who bought ballast water treatment systems (BWTSs) over the past few years.

FIT FOR THE LONG RUN

In the boom days of the ballast water treatment market when shipowners were rushing to meet the IMO deadline for installation, dozens of small suppliers and shipyards got into the business and marketed affordable new systems. At the time, established OEMs cautioned that there would be a wave of consolidation after this big surge died down and that many suppliers would have to exit the market – with implications for long-term aftersales support.

That has indeed turned out to be the case. Some OEMs have thrived. Others have folded. Some have quietly refocused on other products.

The net result is that many owners are already replacing treatment systems that no longer work, are no longer well-supported, or both. They have few other options as port state control (PSC) authorities are ramping up the stringency of their inspection regimes.

"A lot of vessel owners in the early stages chose systems that were cheap, designed by the shipyard, with filters that were not really useful in challenging water conditions," says Rudolph Mes, Senior Vice President of Operations at BWTS supplier Scienco-Fast. "It was more like, 'Let's go for the cheapest one.' Now you see a shift and more people are saying, 'Oh, we have the wrong system. We have to look for a replacement.'"

Common complaints include high maintenance, poor diagnostics, high usage of consumables and poor or slow performance in certain water conditions (excess silt, low temperature or low salinity). For compliance, it's no longer enough to carry a documented BWTS on board. In many ports, the system has to have a record of functionality and crew competency in order to pass muster, much like the ship's oily water separator.

TOUGHER INSPECTIONS

Last year, the Paris and Tokyo MoUs ran a concentrated inspection campaign targeting BWTS functionality, and many owners found out the hard way that their systems needed improvement.

"Shipowners are under growing pressure to demonstrate that their BWTS can operate reliably across different water qualities, trading patterns and ports and that crews are able to explain and defend system operation during inspection," says a spokesperson for leading OEM Alfa Laval. "Tolerance for recurring alarms, derated operation or informal workarounds has decreased significantly."

The new PSC emphasis on checking capability has resulted in a wave of BWTS-related deficiencies, detentions and follow-up inspections in some regions. For shipping, time is money, and an off-hire event because of a simple BWTS failure is a costly problem both in the short term (revenue) and the long term (customer relations).

A growing number of owners are opting to replace unreliable BWTS equipment, finding the expense of an early retrofit to be lower than the lifecycle cost of an unsupported system.

"In many cases, the technical problems they experience are manageable in isolation," says an Alfa Laval spokesperson, "but the lack of confidence that their BWTS supplier will remain engaged, resourced and accountable over the vessel's lifetime becomes the decisive factor." As a replacement, lots of owners are turning to the company's PureBallast 3 retrofit system, and so far Alfa Laval has completed more than 300 projects to remove another OEM's equipment and install its own.

PERFORMANCE TESTING & VALIDATION

For now, most PSC inspection regimes are still looking at records of compliance rather than performing lab tests on actual BWTS discharge water, but there are signs that this may change.

"Some inspection regimes are more stringent, and [with testing] they see that about 30 percent of the currently installed systems are not compliant," says Scienco-Fast's Mes. "So noncompliant water is being pumped over."

For owners, this raises another future-proofing question: Can their BWTS stand up to performance testing and, if so, can they easily demonstrate that the discharge water meets standards? Owners can check it with a lab testing service like SGS's marine services, but some BWTS suppliers offer real-time testing built right into the equipment.

For Scienco-Fast, this is a big selling point. Its InTank chlorination system finishes its work while under way, so the details of chemical treatment can be demonstrated to PSC officials even before water discharge begins. "You can pull out of the system a certificate of compliance that shows which tanks were treated, how long the chemicals were in the tanks, and authorities can see exactly what you've done with your water treatment," Mes says.

In the broader market, inadequate treatment is so common that some ports are looking at setting up dedicated ballast water reception facilities. Bio-UV, a leading BWTS OEM based in France, sees port-side treatment as a growth area for its business as inspection regimes intensify.

To serve this new market, it's partnered with biological monitoring company MicroWISE to build an integrated test-and-treat solution for shoreside ballast water disposal. The combined system gives an assessment of ballast water compliance in real time, at the point of treatment – allowing the port to remediate a ship's noncompliant ballast water without slowing down operations.

"Many ships are fitted with ballast-water systems that do not consistently perform under real operating conditions," says Maxime Dedeurwaerder, Business Unit Director for BIO-UV Group's maritime division. "As a result, the burden of compliance is shifting toward ports, which will need practical, scalable solutions to handle non-compliant discharges."

RETROFIT SKILLS

Many of these big refits have to happen in a shipyard, and yard days cost the owner money twice: once for the shipyard's expenses and once for the lost off-hire time. For OEMs and yards, that means getting vessels in and out fast is key to winning clients for refit work.

During the peak years of BWTS refits, Chinese shipyards reported a 48 percent jump in workload, and many regional yards like Turkey's Tuzla Shipyard and Estonia's BLRT made a name for themselves by doing fast, high-quality work. German water purification specialist Amollo lays out what it takes to compete for refit work, and it isn't easy. The space has to be cleared of existing systems and obstructions and prepared to receive the new equipment, sometimes while the ship is under way. All components must be factory-tested, then each piece has to be moved into the compartment through existing hatches and installed into tight spaces. This kind of work requires adaptability to fit the circumstances of the job.

In the cruise and naval markets, space is especially key. Many of these operators now want to retrofit their blackwater systems to treat their graywater too, says ACO Marine's Head of Sales, Chaitanya Shah. That goes beyond legal requirements, and handling that extra volume requires adding more capacity.

One solution is to buy a big treatment plant that can handle the largest anticipated peaks of graywater and blackwater production. A more creative alternative – and the one Shah recommends – is to convert an existing ballast or blackwater tank space into a holding tank that absorbs all the peak wastewater loads. Then you can install a smaller treatment system that draws down the tank at a constant rate.

The tank conversion requires input from the naval architect, the class society and the shipyard, "but we have made it work very well," says Shah. This saves money and space while allowing the customer to exceed treatment requirements.

WASTE DISPOSAL

Evac Group, one of the largest wastewater treatment suppliers, has another recommendation for cruise operators: carbonizing their messy organic solid waste into biochar. Its newly-developed HydroTreat system takes the ship's food waste and bio-sludge, heats it up to about 400 degrees Fahrenheit and pumps it out as sterilized charcoal.

The biochar can be dewatered and disposed of without further special handling, allowing the ship to handle its own waste under way, avoiding costly in-port sewage fees, over-the-side discharge or emissions-intensive incineration.

Carnival's TUI Cruises is installing the system on three new cruise ships currently under construction. "This is not just a ground-breaking innovation for the cruise industry, but for waste management in general," says Georgios Vagiannis, TUI Cruises' newbuild chief.

The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.

Sunday, April 26, 2026

Our Pee Is Underutilized: Human Urine Could Help Tackle Global Fertilizer And Wastewater Challenges

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Human urine – often flushed away without thought – could be key to making agriculture and wastewater treatment more sustainable and energy efficient, according to new research from the University of Surrey. 

Although urine only makes up around one per cent of wastewater, it contains the majority of essential nutrients for plants, including nitrogen, phosphorus and potassium.  

In a study published in the Journal of Environmental Chemical Engineering, researchers looked into how these nutrients can be recovered and reused by concentrating urine into a fertiliser-rich stream. Using a low-energy process known as forward osmosis, the team were able to remove water and retain high levels of nutrients without the energy demands of conventional wastewater treatment technologies. The approach could reduce the burden on treatment plants while supporting more sustainable fertiliser production. 

Dr Siddharth Gadkari, Lecturer in Chemical Process Engineering at the University of Surrey and lead author of the study, said: 

“It is strange to say, but it has the added benefit of being true – our pee is an underutilised resource. Even though it contains the key nutrients we need for agriculture, we currently treat it as waste. Our research shows that with the right treatment approach, we can recover these nutrients efficiently while reducing the energy demands of wastewater treatment.” 

A major challenge for membrane-based systems is membrane fouling – where biological and organic material builds up on the surface over time and reduces performance. The study provides one of the first detailed insights into how human urine behaves under repeated operation, showing how different conditions affect fouling, system efficiency and cleaning. 

The research team found that simple pre-treatment steps, such as filtration, can significantly improve performance, while most fouling can be reversed through cleaning – making the system more viable for long-term use.  

Dr Gadkari added: 

“What is particularly exciting is that we have demonstrated how this system behaves under realistic conditions using real human urine. If we can effectively manage fouling, this technology can move much closer to practical, long-term use.” 

The work was carried out in collaboration with the University of KwaZulu-Natal in South Africa, where source-separated urine systems are already being explored at scale.  

Researchers believe that their work could help reduce reliance on energy-intensive fertiliser production, lower carbon emissions and support more sustainable water and nutrient management worldwide.