Effect of process parameters on the energy requirement in ultrasonical treatment of waste sludge

Mechanical treatment methods are used as pre-treatment methods in order to enhance the efficiency of conventional sludge treatment processes and the sludge becomes more suitable for its complete treatment. The ultrasound is an alternative method among other methods, but because of its high energy requirement it should be optimized before utilization. This work gives the optimized parameters such as sonication time, sonication power (these parameters are the two factors which play part for energy calculations), type of sludge, cooling requirements and solid content in the sludge solution. Even if the previous researchers prefer to use the energy (specific energy usually), we have found out that both the sonication time and the sonication power have individual importance. For municipal sludge the main conclusion can be summarized as: “high power-short retention time” is more effective than “low power-long retention time”. As this phenomenon may alter from sludge to sludge, various combinations of power and retention time should be tried while keeping the volume small and the concentration below a certain level. The process should be performed at moderate temperatures and the efficiency increases if the sludge is as homogeneous as possible

Quantification of β-lactamase producing bacteria in German surface waters with subsequent MALDI-TOF MS-based identification and β-lactamase activity assay

Environmental oligotrophic bacteria are suspected to be highly relevant carriers of antimicrobial resistance (AMR). However, there is a lack of validated methods for monitoring in the aquatic environment. Since extended-spectrum β-lactamases (ESBLs) play a particularly important role in the clinical sector, a culturing method based on R2A-medium spiked with different combinations of β-lactams was applied to quantify β-lactamase-producing environmental bacteria from surface waters. In German surface water samples (n = 28), oligotrophic bacteria ranging from 4.0 × 103 to 1.7 × 104 CFU per 100 mL were detected on the nutrient-poor medium spiked with 3rd gen- eration cephalosporins and carbapenems. These numbers were 3 log10 higher compared to ESBL- producing Enterobacteriales of clinical relevance from the same water samples. A MALDI-TOF MS identification of the isolates demonstrated, that the method leads to the isolation of environ- mentally relevant strains with Pseudomonas, Flavobacterium, and Janthinobacterium being pre- dominant β-lactam resistant genera. Subsequent micro-dilution antibiotic susceptibility tests (Micronaut-S test) confirmed the expression of β-lactamases. The qPCR analysis of surface waters DNA extracts showed the presence of β-lactamase genes (blaTEM, blaCMY-2, blaOXA-48, blaVIM-2, blaSHV, and blaNDM-1) at concentrations of 3.7 (±1.2) to 1.0 (±1.9) log10 gene copies per 100 mL. Overall, the results demonstrate a widespread distribution of cephalosporinase and carbapen- emase enzymes in oligotrophic environmental bacteria that have to be considered as a reservoir of ARGs and contribute to the spread of antibiotic resistance

Assessment of Arthrobacter viscosus as reactive medium for forming permeable reactive biobarrier applied to PAHs remediation

Polycyclic aromatic hydrocarbons (PAHs) are significant environmental contaminants as they are present naturally as well as anthropogenically in soil, air and water. In spite of their low solubility, PAHs are spread to the environment, and they are present in surface water, industrial effluent or groundwater. Amongst all remediation technologies for treating groundwater contaminated with PAHs, the use of a permeable reactive biobarrier (PRBB) appears to be the most cost-effective, energy efficient, and environmentally sound approach. In this technology, the microorganisms are used as reactive medium to degrade or stabilize the contaminants. The main limits of this approach are that the microorganisms or consortium used for forming the PRBB should show adequate characteristics. They must be retained in the barrier-forming biofilm, and they should also have degradative ability for the target pollutants. The aim of the present work is to evaluate the viability of Arthrobacter viscosus as bioreactive medium for forming PRBB. Initially, the ability of A. viscosus to remove PAHs, benzo[a]anthracene 100 μM and phenanthrene 100 μM was evaluated operating in a batch bench-scale bioreactor. In both cases, total benzo[a]anthracene and phenanthrene removals were obtained after 7 and 3 days, respectively. Furthermore, the viability of the microorganisms was evaluated in the presence of chromium in a continuous mode. As a final point, the adhesion of A. viscosus to sepiolite forming a bioreactive material to build PRBB was demonstrated. In view of the attained results, it can be concluded that A. viscosus could be a suitable microorganism to form a bioreactive medium for PAHs remediation.This work has been supported by the Spanish Ministry of Economy and Competitiveness and FEDER Funds (Project CTM 2011-25389). Marta Pazos received financial support under the Ramon y Cajal programme and Marta Cobas under the final project master grant "Campus do Mar Knowledge in depth"

Metatranscriptomic insights into aerobic biotransformation of 6:2 fluorotelomer sulfonate by an enrichment culture under sulfur-limiting conditions

6:2 Fluorotelomer sulfonate (6:2 FTS), an alternative for PFOS, has become an environmental concern due to its toxicity. This study investigated the aerobic biotransformation of 6:2 FTS under sulfur-limiting conditions using an enrichment culture, SXC01. The enriched culture achieved ≥99.5% degradation of 6:2 FTS at initial concentrations of 0.5, 2.5, and 5 mg/L within 14 days, with notable corresponding defluorination ratios of 77.2%, 28%, and 16.8%, respectively. Eleven transformation products were identified and quantified over time, and the accumulation of intermediate product 6:2 FTUCA suggested that its further degradation may represent a rate-limiting step. Furthermore, the production of PFHxA is more significant than that of PFBA, suggesting the transformation of 6:2 FTUCA via 5:2 sFTOH pathway is more dominant than the other proposed alternative pathway. Metatranscriptomic analysis revealed the upregulation of key genes associated with desulfonation (e.g., ssuEADCB cluster, cysI, sbp, iscS) and defluorination (e.g., ladA, dehH, crcB, dhaA), indicating a synergistic metabolic network driving 6:2 FTS biotransformation. Active genera identified included Brucella, Rhodococcus, and Pseudoclavibacter. Moreover, the predominant Brucella anthropi SX009 was successfully isolated and shown to completely degrade 6:2 FTS within 14 days. This study provides novel insights into the mechanisms of 6:2 FTS biotransformation.This research was funded by the National Natural Science Foundation of China (NSFC)-EU Environmental Biotechnology Joint Program (No. 32061133001), and the National Natural Science Foundation of China (No. 42277029). We acknowledge the cooperation between China and the EU through the EiCLaR project (European Union’s Horizon 2020, No. 965945).Environmental Science & Technolog

Characterisation and optimisation of an automated ultrafiltration system used for the concentration of waterborne viruses, bacteria and protozoa

Waterborne pathogen detection is challenging, requiring effective target organisms enrichment to enable reliable and accurate monitoring of pathogens which could be present at low numbers. However, existing processes are manual, require operator expertise and are optimised for particular applications, e.g. a certain approach for viruses and another for bacteria etc. This study presents the design, development, and optimisation of an easy-to-use automated Rexeed™ dead-end filtration system tailored for concentrating multiple waterborne pathogens including viruses, bacteria and protozoa within a single unit. Knowing the variability in recovery rates across filtration technologies due to factors such as filter type, pre-treatment chemicals, backflush volumes, and flow rates, this system was engineered to optimise pathogen recovery and improve consistency in sample processing, generating a system that reduces manpower requirements and worked well across viruses, bacteria and protozoa.System parameters were investigated, including flow rates of filtration from 0 to 1200 mL/min, backflush volumes ranging from 0 to 500 mL, chemicals used for backflush water enhanced with surfactants and chemical dispersants. Additionally, pre-treatments with sodium polyphosphate (NaPP) and bovine serum albumin (BSA) were investigated using fluorescent beads as proxies for pathogens.Key results indicate that high flow rates (≥ 900 mL/min), backflush volume of 250 mL containing NaPP, Tween and antifoam achieved significantly higher recovery rates. Validation using fluorescent particle counting and turbidity measurements confirmed that this automated setup yields recovery rates in line with existing filtration methods. By enabling simultaneous concentration of diverse pathogens, this automated system offers a practical solution for comprehensive waterborne pathogen monitoring, demonstrating that one automated filtration unit can effectively concentrate multiple pathogens

Performance of Layer-by-Layer-Modified Multibore® Ultrafiltration Capillary Membranes for Salt Retention and Removal of Antibiotic Resistance Genes

Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO$_{4}$, CaCl$_{2}$ and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO$_{4}$ and CaCl$_{2}$ salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemical regeneration (in acidic conditions and basic/oxidizing conditions)

Characterisation and optimisation of an automated ultrafiltration system used for the concentration of waterborne viruses, bacteria and protozoa

Waterborne pathogen detection is challenging, requiring effective target organisms enrichment to enable reliable and accurate monitoring of pathogens which could be present at low numbers. However, existing processes are manual, require operator expertise and are optimised for particular applications, e.g. a certain approach for viruses and another for bacteria etc. This study presents the design, development, and optimisation of an easy-to-use automated Rexeed™ dead-end filtration system tailored for concentrating multiple waterborne pathogens including viruses, bacteria and protozoa within a single unit. Knowing the variability in recovery rates across filtration technologies due to factors such as filter type, pre-treatment chemicals, backflush volumes, and flow rates, this system was engineered to optimise pathogen recovery and improve consistency in sample processing, generating a system that reduces manpower requirements and worked well across viruses, bacteria and protozoa. System parameters were investigated, including flow rates of filtration from 0 to 1200 mL/min, backflush volumes ranging from 0 to 500 mL, chemicals used for backflush water enhanced with surfactants and chemical dispersants. Additionally, pre-treatments with sodium polyphosphate (NaPP) and bovine serum albumin (BSA) were investigated using fluorescent beads as proxies for pathogens. Key results indicate that high flow rates (≥ 900 mL/min), backflush volume of 250 mL containing NaPP, Tween and antifoam achieved significantly higher recovery rates. Validation using fluorescent particle counting and turbidity measurements confirmed that this automated setup yields recovery rates in line with existing filtration methods. By enabling simultaneous concentration of diverse pathogens, this automated system offers a practical solution for comprehensive waterborne pathogen monitoring, demonstrating that one automated filtration unit can effectively concentrate multiple pathogens. [Abstract copyright: Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.