Thirty-one laboratories measured biochemical methane potential (BMP) of six substrates in a project aimed at improving BMP measurement quality. Laboratories used their established measurement procedures, with limited standardization. As in earlier studies, reproducibility was quantified, but here laboratories came from a wide geographic range, and the accuracy of BMP measurements was assessed by comparison with 6 experienced “reference” laboratories. Measurement reproducibility between the remaining “evaluation” laboratories was poor in the first test; relative reproducibility standard deviation was 21–33% for four substrates. Values improved to 9–19% in the second test following review of a detailed analysis of submitted data, troubleshooting meetings, and method modifications by some laboratories. Reference laboratories performed better, with reproducibility standard deviation of 5–12%. Repeatability within laboratories was also better for the reference group, with relative standard deviation of 2–4% vs. 3–7% for evaluation laboratories. Evaluation laboratory results showed a persistent negative bias of 4–16% compared to reference laboratories. Application of cellulose validation criteria improved reproducibility but not accuracy. Most of the extreme BMP values were associated with abnormal methane production curves, and a subjective visual evaluation proved valuable as a screening tool. The cause of measurement error was generally unknown, although data processing and volatile solids measurement errors caused some extreme results, and changes in inoculum source improved performance in two cases. There were no consistent differences among the diverse measurement methods and the sources of error probably vary among laboratories. Consistently accurate BMP measurement is possible for laboratories that follow established guidelines and develop experience.
In the paper, the advisory council argues in favour of a multidimensional security architecture. It should not only link the fight against environmental risks more closely with security policy instruments, but also incorporate other issues.
Overall, the WBGU has identified five areas of action that it considers crucial in the national and international security context:
🔹 1. Protection against climate change, biodiversity loss and pollution to preserve the viability of humanity.
🔹 2. Social cohesion to promote resilient societies.
🔹 3. Information integrity to make democracy resilient (wehrhaft).
🔹 4. Balanced use of technologies and raw materials to reduce dependencies.
🔹 5. Strategic, rules-based and fair collaboration to support international cooperation.
The WBGU has stimulated the security-policy debate further by developing specific recommendations for action in all five fields, for example on the topic of 'security through climate protection', on designing technological sovereignty, dealing with AI-generated misinformation and socially divisive communication, and on restructuring international cooperation.
Lead authors of the short paper are: Jörg E. Drewes, Anna-Katharina Hornidge, Aletta Bonn, Kai Maaz, Karen Pittel, Hans Pörtner, Sabine Dr. Schlacke, Claudia Traidl-Hoffmann, Joscha Wullweber.
Security – sustainable and integrated
Source: Bundesministerium für Umwelt, Klimaschutz, Naturschutz und nukleare Sicherheit (BMUKN)
The joint project "Water Resilience" shares its initial findings at the 59th Essener Conference with a talk and a poster presentation: "Requirements and structure of AI-supported optimisation of groundwater management and load management at Hessenwasser GmbH & Co KG".
Applying the counter-current principle, i.e. recirculating half-loaded PAC into the activated sludge process, will boost your process performance!
Curious?
Check out our open-access publication:
https://www.nature.com/articles/s41545-026-00561-y
Big thanks to Max Zimmermann, all involved project partners and BMFTR for funding this study.
Calcium precipitation in granular sludge frequently threatens the stability and efficiency of biological nitrogen removal, yet most studies focus on slow, progressive calcification during long-term operation. Here, we report for the first time a transient calcification phenomenon in PD-HAP coupled granular sludge, where nitrite accumulation activity collapses within 24 h under fluctuating influent conditions (NO3−-N deficiency). Microstructural analyses revealed that amorphous calcium phosphate (ACP) initially deposits on the granule surface and migrates inward through axial mineral channels driven by microbial metabolism. Through the Ostwald ripening process, ACP gradually transforms into hydroxyapatite (HAP), simultaneously forming the characteristic Liesegang ring patterns. When microbial activity declines and migration driving forces are insufficient, surface deposition outpaces inward transformation, generating a transient calcium crust that blocks substrate-bacteria contact and triggers rapid activity loss. Over time, the repeated occurrence of such surface deposits and mineral phase transformations can ultimately form a more compact and stable mineral coating, exhibiting characteristics of progressive long-term calcium accumulation. Notably, this granular system achieves self-regulation by fracturing into functional micro components (d < 0.2 mm), thereby restoring the system's exceptional nitrite accumulation capacity. These results elucidate the mechanistic basis of transient calcification, highlight the critical role of microbial metabolism in controlling calcium migration, and provide actionable strategies for mitigating calcification shocks in industrial wastewater treatment. Understanding these processes offers a foundation for designing granular sludge systems with enhanced resilience against sudden influent fluctuations and high-calcium wastewater.
Building products, like non-metal roofing materials, can contribute pollutants to stormwater. Laboratory leaching tests, particularly the dynamic surface leaching test (DSLT), are employed to evaluate the substance release, but are not designed to simulate field conditions. By comparing results from a DSLT and a 6-month field study for the same materials (clay tiles, concrete tiles, fiber cement sheets, bitumen shingles, treated wood shingles, and plastic tiles) and same analyzed inorganic and organic parameters we provided a basis for interpreting and translating the DSLT outcome to real weather conditions. The objective was to evaluate the reliability of the DSLT in predicting which parameter types are leached from non-metal roofing materials in the field, as well as its suitability for estimating the corresponding concentration levels. The comparison demonstrated that the DSLT reliably predicted more than 80% of pollutants released under environmental conditions, supporting its use for investigating new roofing materials or emerging pollutants to identify parameters contributing to stormwater pollution. Our results serve as a database for interpreting DSLT results and for developing and calibrating transfer models. However, no general pattern was observed between laboratory and field results: for fiber cement, clay and concrete tiles, the DSLT overestimated the concentrations; median concentrations exceeded those in the field, with factors of 2.6 to 115. For bitumen and wood shingles, the DSLT rather underestimated the substance release, resulting in median field concentrations that exceeded those in the laboratory by factors of 1.3 to 10.4. Consequently, transfer models must account for different surface properties of the materials.
Leachate infiltration into groundwater is an intensifying environmental and public health concern in many developing countries, where waste disposal systems are poorly engineered. Phenolic contaminants pose significant ecological and human health risks but remain understudied in sub-Saharan Africa. This study investigated the seasonal occurrence, distribution, and associated risks of four phenolic compounds, namely bisphenol A (BPA), hydroquinone (HQ), resorcinol (RE), and benzoquinone (BQ), in groundwater sources near municipal dumpsites across three Southwestern States in Nigeria. Groundwater samples were collected from rural and urban areas across Osun, Oyo, and Lagos States during both rainy and dry seasons. Solid-phase extraction and high-performance liquid chromatography-ultraviolet detector (HPLC-UV) analysis were used to extract and quantify the target analytes, followed by multivariate statistical evaluation, human health risk assessment, and ecological risk assessment. Concentrations of BPA, HQ, RE, and BQ were generally higher during the dry season, especially in Osun and Lagos States. BPA recorded the highest values, peaking at 20.90 mg L−1 in urban Osun. RE and BQ also showed elevated levels during the dry season, particularly in urban Lagos and rural Oyo, respectively. HQ exhibited variable trends, with significant peaks in rural Oyo (11.93 mg L−1) and rural Osun (7.26 mg L−1). Multivariate analysis via principal component revealed clear seasonal differentiation and strong co-loading patterns consistent with leachate-driven contamination processes. Human health risk assessment indicated that estimated daily intakes in children frequently exceeded stipulated limits, while ecological risk assessment identified Daphnia magna as the most sensitive species, with acute and chronic risk quotients exceeding the reference dose in several locations. This study represents the first year-long, multi-state assessment of phenolic contaminants in Nigerian groundwater and provides critical evidence of contamination levels linked to unmanaged waste sites. These findings highlight the urgent need for improved waste management, groundwater protection policies, and expanded toxicological evaluation of phenolic contaminants in rapidly urbanizing regions of sub-Saharan Africa.
On March 19, we are hosting a C.A.R.M.E.N. expert forum on the topic of ‘Biological Methanation’ at our chair, including a guided tour of our pilot plant at the Garching wastewater treatment plant. We are looking forward to welcoming many participants.
Further information and registration are available at https://www.carmen-ev.de/events/c-a-r-m-e-n-fachgespraech-biologische-methanisierung/.
An automated sampling system has been installed on a 1000m² green roof at the O2-Surftown in Hallbergmoos, and a student research assistant is needed to further process the samples.
Working hours: approx. 8 hours per week
Location: TUM Campus Garching (Chair of Urban Water Management, SiWaWi)
Start date: April 2026
Glyphosate formation from detergents in sewage treatment plants? What's the truth? See minute 8:00.
This study investigated the performance and nitrous oxide (N₂O) emission dynamics of algal-bacterial granular sludge (ABGS) cultivated in a 40 L sequencing batch photobioreactor (SBPBR) treating real domestic wastewater, without initial external inoculum. ABGS formation was successfully achieved and remained stable over 180 days, with stable granule structure (> 1000 µm), good settling properties (SVI₃₀ of 42 mL· gVSS⁻¹), and chlorophyll-a content of 1.2 ± 0.1 mg· gVSS⁻¹. The system remained resilient to disturbances, including tubifex proliferation, confirming the structural viability of ABGS under non-sterile conditions. Regarding treatment performance, the reactor achieved consistent COD removal (> 80 %) and efficient ammonium removal (> 97 %) after microbial community adaptation. However, phosphorus removal was moderate (52 %), limited by the lack of anaerobic cycling and absence of excess sludge removal. N2O dynamics were monitored under four operational scenarios: low/high dissolved oxygen (DO) (2–3 and 6–7 mg· L⁻¹) and with/without light. N₂O production on liquid phase was mainly influenced by DO concentration, as lower DO levels resulted in higher N₂O emissions, while light had only a minor effect on its dynamics. However, under high DO conditions (10 L· min⁻¹, kLa = 283 h⁻¹), N₂O in the gas phase (emission factor, EF) reached 3.4 %, which was considerably higher than under low DO (3 L· min⁻¹, kLa = 100 h⁻¹), where EF remained below 1 %. This outcome indicates that oxygen availability is the dominant driver of N₂O formation, with light exerting only a secondary influence. These results emphasize the dual control of N₂O by microbial pathways and physical mass transfer, underscoring the need to optimize aeration strategies in ABGS reactors to balance nitrogen removal and greenhouse gas mitigation.
The Water Hub research facility is managed by the University of Cape Town’s Future Water Institute and is located in Franschhoek.
A PhD scholarship is being offered for research that focuses on advancing the use of nature-based treatment to remove organic matter, pathogens, contaminants of emerging concern (CECs) and excessive nutrient loads from decentralised wastewater streams. This project forms part of an ongoing programme with international collaborators demonstrating how low-energy, low-cost natural treatment systems can support safe water reuse and improved water security in resource-constrained contexts.
Location: The Water Hub, Franschhoek, South Africa
Starting Date: 2026
Duration: 3 years, full-time
A PhD scholarship is being offered to research the optimisation and assessment of the operation of a 100kg containerised biodigester system capable of converting food and organic waste into biogas for heating and refrigeration and using digestate for small-scale agroecology production.
Location: The Water Hub, Franschhoek, South Africa
Starting Date: 2026 (flexible)
Duration: 3 years, full-time
Today, the drinking water limit for the sum of 20 PFAS came into force. This means that PFAS are now regulated in the EU and Germany for the first time. If you want to know what this means for you and what measures you as a supplier must now take in the event of exceedances, then register for our 34th Water Technology Seminar (WTS) on February 4, 2026. In our webinar, we provide comprehensive information on the latest developments relating to PFAS.
https://www.cee.ed.tum.de/en/sww/foundation/registration-for-34-wts/
As urban road runoff is a critical source of water contamination, it poses a persistent challenge to water quality management, particularly in compact cities. Yet the sources, transport mechanisms, interactions, and ecological risks of these co‑occurring contaminants remain insufficiently understood. Therefore, we investigated 32 stormwater quality parameters in runoff from six representative road sites across 11 rainfall events over a 17-month period in Hong Kong. Contaminant levels in initial road runoff were markedly higher than those in natural rainwater; notably, Escherichia coli concentrations were more than four orders of magnitude greater. Concentrations of organic matter, solids, nutrients, pathogens, and metals in the initial road runoff exceeded the Water Pollution Control Ordinance (WPCO) objectives in Hong Kong by several to dozens of times. A pronounced first flush effect was observed for chemical oxygen demand (COD), total suspended solids (TSS), zinc (Zn), and microplastics (MPs). MPs correlated positively with pH, E. coli, phosphate (PO43−), and nitrate nitrogen (NO3—N), and negatively with dissolved oxygen (DO) and iron (Fe), suggesting their role as vectors for nutrients and pathogens under oxygen-poor, biologically enriched conditions. Contaminant levels varied by land use and season, with higher concentrations on residential roads and winter peaks for COD, chloride (Cl−), Zn, Fe, and TSS. Ecological risk indices indicated very high metal risk, primarily from lead (Pb) and nickel (Ni), and moderate-to-high polymer risk from polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA). These findings highlight road runoff as a key driver of urban water quality degradation, emphasizing the importance of managing first-flush discharges through land–use–specific controls, seasonally optimized street cleaning, and targeted treatment of high-risk contaminants.
As part of the Engineered Natural Treatment Systems (ENTS) course taught by Benedikt Aumeier, we visited the Irschenberg wastewater treatment plant on Wednesday 12.12.2025. There is a lot going on there right now: the plant is being expanded from 5,000 to 7,000 PE and is being equipped with a stage for the removal of trace organic chemicals (TOrCs) – implemented as an innovative vertical filter Biofiltrationplus.
What’s behind the Biofiltrationplus? A system that not only reliably removes micropollutants, but also serves as a buffer for the effluent. The filter combines sand (biological degradation of TOrCs) and granular activated carbon (adsorption). This protects the sensitive receiving water from TOrCs loads and effectively intercepts discharge peaks.
Mr. Schmidt, the plant manager, guided us from the inlet to the outlet through the construction site, sharing valuable technical insights along the way. The main focus of the filed trip was the new Biofiltrationplus, whose planning our chair has supported as part of a doctoral research project (Anna-Sonia Kau, Dr. Benedikt Aumeier, Prof. Jörg E. Drewes). We will also be responsible for operational support for the filter after it goes into operation in May 2026. The Biofiltrationplus will be one of the first plants for TOrCs removal in Bavaria. The project is funded by the Bavarian Ministry of the Environment, Urban Development and Energy (StMUV) and is intended to serve as a blueprint for many other small wastewater treatment plants. You can find out more about the project here.
A clear highlight for the students was the already fully filled filter – they were visibly impressed to experience such an innovative engineered natural treatment system in practice.
Many thanks to Mr. Schmidt for his great support during the excursion!