Removal Of Pathogens Research Articles

Biological and ecological consequences of combined biofilm, shellfish and phytoremediation along a wastewater treatment system from shrimp aquafarm

Biological treatments have been widely applied to remove wastewater nutrients, while single biological treatment is insufficient to achieve desired efficiency. Moving beyond removal of nutrient, equivalent focus on ecological consequences and biotic pollutants (e.g., pathogens) along the decontamination procedures is lacking. Herein, we established an efficient biological treatment system by integrating biofilm, shellfish and Spartina, which efficiently reduced the levels of wastewater nutrients (> 62.7 %) and sediment antibiotics (> 84.6 %) before discharge, with unsatisfied removal of total phosphorus and diversified potential pathogens. Our biological treatments potentiated C storage and ammoxidation process, and mitigated CH4 emission, of which are conjointly governed by the direct effect of nutrient pollutions and the indirect effect of antibiotics. In contrast, denitrification potential in wastewater and sediment was divergent, resulting in an uncertainty on net N2O emission. We identified diverse ammonia-oxidizing bacteria assistors that were candidates for improving ammoxidation. Intriguingly, bacterial biomakers could quantitatively and accurately diagnose wastewater entropy water quality index and sediment multi-nutrient cycling index, with overall 81.9 % and 91.1 % accuracy, respectively. The combined biological treatments can be a double-edged sword between water quality improvement and mitigating pathogenicity. These findings greatly deepen our understanding of the biological and ecological consequences of a biofilm-shellfish-phytoremediation system, and accordingly some strategies are informed for improving decontamination efficiency.

Advanced Nitrogen and Pathogenic Indicator Removal from Digested Livestock Wastewater Using a Partial Nitritation-Anammox Coupled with Partial Denitrification (PN-APD) Process without an External Carbon Source

Advanced Nitrogen and Pathogenic Indicator Removal from Digested Livestock Wastewater Using a Partial Nitritation-Anammox Coupled with Partial Denitrification (PN-APD) Process without an External Carbon Source

Unveiling mechanistic intricacies of Chlorella pyrenoidosa-mediated pathogen removal from sewage

Amidst the global sanitation challenges of water pollution, waterborne diseases, and the alarming presence of pathogens in disinfected water, microalgal technology has emerged as a viable alternative for wastewater treatment. Recently, the ability of microalgae to remove pathogens from wastewater has been highlighted. However, a critical knowledge gap exists regarding microalgae-mediated pathogen removal mechanisms. The present study uncovers the intricate mechanisms of Chlorella pyrenoidosa-mediated Escherichia coli removal from sewage. Microalgae-induced pH increase was identified as the most crucial mechanism, followed by photooxidation and attachment, mediated by the hydroxyl group. Longer photoperiods or ultraviolet irradiation produced high oxidative stress, promoting microalgal exopolysaccharides’ production and increasing pathogen entrapment. The knowledge of crucial removal mechanisms can be harnessed for the development of more efficient, innovative, and scalable microalgal systems. Such improved systems offer a sustainable solution to address water-related issues by improving wastewater treatment, increasing access to clean water, and reducing the transmission risk of waterborne diseases.

Effect of Moringa oleifera seeds on the removal of pathogens and pharmaceutical residues in a domestic wastewater treatment plant by an interdisciplinary approach

In this transdisciplinary study, we investigated, using genomic tools and physico-chemical parameters, the effect of Moringa oleifera seed (MOS) on the removal of microorganisms and pharmaceutic residues (antibiotics), and also the development of antibiotic-resistant genes (ARGs) in water samples from a domestic wastewater treatment plant (WWTP) prototype. Water samples were analyzed with and without the addition of powder of MOS. The results showed that MOS addition reduced the total bacterial load from 1.73 × 1010 ± 3.21 × 109 to 6.67 × 106 ± 5.77 × 106 CFU/L, while fecal coliforms and Escherichia coli were removed with efficiencies of 99% and 57%, respectively. Furthermore, MOS treatment resulted in a reduction in fecal coliforms and E. coli resistant to ampicillin by about 100% and 96%, respectively. The results indicated that ciprofloxacin removal efficiencies at 29 °C were over 93% (fecal coliforms) and 68% (E. coli) with doxycycline. Adding MOS significantly reduced the copy number of the 16S rRNA gene and the genes conferring resistance to β-lactam (blaCTX-M, blaSHV, and blaTEM). However, MOS does not reveal real effectiveness on removal of pollutants (phosphorus and nitrates) contrary to what was expected. Additional studies are needed for confirmation from our observations. The findings of this study, whatever the functioning conditions (not optimal) of the prototype followed over 4 years, confirmed that MOS is potentially an effective natural and environmentally friendly coagulant that could be applied to wastewater treatment in low-income countries to remove or minimize multiple pollutants and control ARG spread. To promote sustainable development, this small-scale study provides guidance for designing infrastructure in resource-limited locations to take advantage of MOS effects in wastewater treatments.Graphical An individual WWTP prototype was installed in Senegal in 2018 and evaluated in 2020 and 2022. MOS powder addition is supposed to reduce bacterial loads and pharmaceutical residues in wastewater from the WWTP. Evaluation of treatment efficiency was carried out based on using chemistry, microbiology, genomics, physic-chemistry, and statistics analysis.

Towards the definition of treatment wetland pathogen log reduction credits.

Treatment wetlands have the potential to treat a range of water and wastewater pollutants while using less energy and chemicals than conventional treatment processes, making them a viable option for improving the sustainability of water treatment systems. However, water treatment systems used for water reuse must also be protective of human health. To date, the human health protection benefits of treatment wetlands have not been rigorously quantified in the context of current human health risk frameworks. This study presents a comprehensive review of the ability of treatment wetlands to provide reliable pathogen reduction to meet risk-based treatment targets for water reuse. Following an existing protocol for establishing log reduction credits, we systematically reviewed the documented pathogen reduction performance of major treatment wetland types in terms of core components of that protocol, including pathogen removal mechanisms, identification of target pathogens, and influencing factors. Results of the review point to design and operational conditions under which treatment wetlands could likely be credited with a log reduction value of approximately 0.5 or greater for virus, protozoa and bacteria. These conditions are specified in terms of preliminary operating envelopes, or design and operational parameter windows associated with optimal performance. Important caveats are noted, as are specific and tractable recommendations for future research and data collection efforts that would help refine operating envelopes and define log reduction credits for these promising water treatment technologies. As a resource to other practitioners, we have also included the detailed performance characterization database as Supplemental Information. This database includes a detailed tracking of log reduction values as well as design and operational parameters reported in the literature.

Pathogen validation of small- and large-scale recycled water plants utilizing various clarification and media filtration technologies.

Media filters are important in wastewater recycling schemes for pathogen removal. Filter selection depends on health targets and plant scale; however, there is a data gap concerning pathogen removal efficacy at full scale. This study compared the pathogen removal performance of two full-scale filtration technologies, including a small 17,000 m3/d pressurized media filtration (PMF) plant and a large 120,000 m3/d gravity filter in the form of dissolved air flotation filtration (DAFF). The preceding clarification processes were also assessed. Validation of protozoa and virus removal was estimated by dosing model organisms yeast and MS2 bacteriophage to demonstrate removal potential. The DAFF process (coagulation, flotation and filtration) was most efficient at removing bacteriophage with a mean log10 reduction value (LRV) of 2.90 (±0.64), compared with 0.98 (±0.37) achieved by coagulation, sedimentation and PMF. Yeast log10 reduction though both systems were similar measuring 3.80 (±1.06) through DAFF and 4.57 (±0.14) through coagulation, sedimentation and PMF. The DAFF process showed greater variability in MS2 and yeast removal, which was attributed to filtration. Energy and chemical usage were also evaluated, revealing trade-offs between these factors, treatment scale and pathogen LRVs, offering practical insights into the technological and economic aspects of designing fit-for-purpose recycled water schemes.

The cGAS-STING mediated crosstalk between innate immunity and autophagy in leishmaniasis using mathematical modeling: Uncovering new therapeutic avenues

The present paper deals with the investigation into the cGAS-STING pathway, focusing on the signaling of interferons through mathematical modeling and identifying a significant positive feedback loop regulated by STING for activation of type 1 interferons (IFN-1). Cyclic GMP-AMP synthase (cGAS) is responsible for detecting cytosolic DNA and initiating the STING (stimulator of interferon genes) pathway, which in turn causes the synthesis of pro-inflammatory cytokines and type I interferons. In addition to being crucial for pathogen identification, this route interacts with autophagy, a cellular mechanism that is necessary for immunological homeostasis and pathogen removal. In the context of Leishmania infection, the cGAS-STING signaling axis has come to light as a critical mediator of the crosstalk between innate immunity and autophagy. Further, the protein-protein interaction studies underscored the significance of two distinct domains in mediating interactions with IRF3 and LC3. Importantly, our findings suggest the possibility of manipulating STING concomitantly to regulate IRF3 and LC3 independently. This study remarkably advances our understanding of STING's multifaceted roles, particularly in regulating IFN-1 and autophagy, highlighting its pivotal role as a cross-talk point in leishmaniasis.

Evaluation of patients undergoing therapeutic plasma exchange in the pediatric intensive care unit and determining the factors affecting prognosis.

Therapeutic plasma exchange (TPE), an extracorporeal method targeting the removal of large molecular weight pathogens, is explored in this study for indications, complications, prognosis, safety, and effectiveness. The patients' data were collected retrospectively. Overall, 334 sessions of TPE were applied to 57 patients. Per the American Society for Apheresis classification, 24.6% of indications fell under Category I, 14% Category II, and 50.9% Category III. Sepsis-induced multiorgan dysfunction syndrome (MODS) emerged as the leading indication, correlating with elevated needs for mechanical ventilation (MV), increased failed organs, and heightened mortality. Patients undergoing continuous renal replacement therapy faced a 16.06 times higher mortality risk. Non-survivors exhibited higher comorbidity, prolonged MV, increased inotropic drug requirement, more failed organs, and a higher PRISM score. 33.2% of complications occurred, primarily catheter-related. Sepsis-induced MODS and extracorporeal modalities are associated with increased mortality in TPE patients, with comorbidities, ventilation, and PRISM scores potentially influencing outcomes.

Full-spectral response of mesoporous Z-scheme nanoheterojunction NaYF4:Yb,Tm@ZnO/BiOI photocatalysts for simultaneous contaminant and pathogen elimination in wastewater

The increasing contamination of water bodies demands effective and economical solutions for wastewater treatment. This study introduces a novel Z-scheme photocatalyst, NaYF4:Yb,Tm@ZnO/BiOI (UZB), synthesized via a simple chemical route. UZB exhibits exceptional photocatalytic degradation efficiencies of 95.1 %, 88.7 %, and 56.3 % for methyl orange under full spectrum, visible, and near-infrared light, respectively. The integration of heterostructures within UZB promotes efficient charge carrier separation, significantly boosting its photocatalytic activity. When applied to actual wastewater, UZB markedly reduces chemical oxygen demand (COD) and total organic carbon (TOC) by 94.1 % and 53.2 %, respectively, and also effectively decreases turbidity and ammonia concentrations. Additionally, UZB shows strong antibacterial effects against S. aureus and E. coli, with inhibition rates of 93.9 % and 92.0 %, though some cytotoxicity is noted. These results underscore UZB's potential as a highly efficient photocatalyst for the simultaneous removal of organic pollutants and pathogens from wastewater, supporting its application in industrial water treatment systems.

Enhancing Sewage Sludge Stabilization, Pathogen Removal, and Biomass Production through Indigenous Microalgae Promoting Growth: A Sustainable Approach for Sewage Sludge Treatment

Sewage sludge (SS), a byproduct of wastewater treatment plants, poses significant environmental and health risks if not properly handled. Conventional approaches for SS stabilization often involve costly and energy-consuming processes. This study investigated the effect of promoting native microalgae growth in SS on its stabilization, pathogen bacteria removal, and valuable biomass production. The effect on settleability, filterability, and extracellular polymeric substances (EPSs) was examined as well. Experiments were conducted in photobioreactors (PBRs) without O2 supply and CO2 release under controlled parameters. The results show a significant improvement in SS stabilization, with a reduction of volatile solids (VSs) by 47.55%. Additionally, fecal coliforms and E. coli were efficiently removed by 2.25 log and 6.72 log, respectively. Moreover, Salmonella spp. was not detected after 15 days of treatment. The settleability was improved by 71.42%. However, a worsening of the sludge filterability properties was observed, likely due to a decrease in floc size following the reduction of protein content in the tightly bound EPS fraction. Microalgae biomass production was 16.56 mg/L/day, with a mean biomass of 0.35 g/L at the end of the batch treatment, representing 10.35% of the total final biomass. These findings suggest that promoting native microalgal growth in SS could be sustainable and cost-effective for SS stabilization, microalgal biomass production, and the enhancement of sludge-settling characteristics, notwithstanding potential filtration-related considerations.

Effect of ozone on Vibrio removal in a simulated earthen shrimp pond

ABSTRACT This study investigated the efficacy of ozone treatment on Vibrio pathogen removal within a simulated earthen shrimp pond, conducted in three phases. First, physical and chemical properties of the soil, alongside the Vibrio pathogen, were assessed. Results indicated neutral pH levels, high organic matter, and organic carbon content, with a Vibrio pathogen load of 1.0 ± 0.0 × 103 CFU/mg. Second, ozone treatment was applied, comparing its effectiveness in Vibrio pathogen control between treated and untreated soil sets. The treated set exhibited a significantly lower Vibrio pathogen load (6.00 ± 1.41 × 103 CFU/mg) compared to the untreated control (2.00 ± 2.12 × 105 CFU/mg), resulting in a 97.23% eradication efficiency. Concurrently, ammonia rates decreased with ozone, indicating potential benefits for shrimp aquaculture. Finally, ozone application in a simulated earthen pond over 45 days effectively controlled Vibrio pathogens. In the untreated soil set, Vibrio pathogen levels rose to 9.48 ± 1.73 × 105 CFU/mg, while in the ozone-treated, they ranged from 6.5 ± 2.12 × 103 to 1.25 ± 0.29 × 105 CFU/mg. Shrimp growth parameters, including average daily gain, survival rates, and feed conversion ratio, were compared between groups, suggesting ozone treatment's feasibility without adverse effects on shrimp growth. Water quality parameters remained within suitable ranges for shrimp cultivation. These findings highlight ozone's potential as an effective method for Vibrio pathogen control in shrimp aquaculture, with implications for industry sustainability and productivity.

A review of pathogen removal from municipal wastewater using advanced oxidation processes: Agricultural application, regrowth risks, and new perspectives

Pathogen removal in wastewater offers a chance to recover water and nutrients for crop production, reducing environmental contamination and public health risks. However, the risk of pathogens regrowing in treated effluents can endanger public health if reused in agriculture, attracting stringent reuse standards. While advanced oxidation processes (AOPs) promise to reduce pathogens, eliminating regrowth potential in AOP-treated effluents requires further scrutiny. This review aimed to summarize the available evidence on understanding pathogen reduction and regrowth potential in AOP-treated effluents, following best practices for scoping reviews like the preferred reporting items for systematic reviews and meta-analysis (PRISMA). It covers recent pathogen studies under AOPs, current AOP investigations, the impact of AOP dosage and retention time on pathogen control, and challenges in reusing AOP-treated effluents for crop production. Additionally, it identifies areas needing improvement or complementary treatments for pathogen-free effluents with no regrowth potential. The review concludes by summarizing key findings and suggesting research areas for further exploration.

Evaluation of physical, chemical, and microbiological characteristics of waste stabilization ponds, Giza, Egypt

Wastewater treatment plants (WWTPs) contain a diverse array of microbes, underscoring the need for regular monitoring to ensure treatment efficacy and protect health. However, detailed studies on waste stabilization ponds (WSPs) are scarce. This study evaluates a full-scale WSP, located in Giza Governorate, Egypt, including anaerobic, facultative, and maturation ponds, examining an array of parameters such as enteric viruses, microeukaryotes (protozoa and algae), bacterial indicators, bacterial pathogens, and physicochemical characteristics. Utilizing multivariate statistical models, we identified significant distinctions in physicochemical parameters and microbial communities, primarily driven by treatment stages rather than temporal variations. In addition, seven viruses (human rotavirus, adenovirus, norovirus, astrovirus, hepatitis A virus, polyomavirus, and papillomavirus) were detected during the different stages (inlet, anaerobic, facultative, and outlet) of the WSP, except norovirus and papillomavirus were absent in the outlet stage. The viral log means reductions ranged from 1.24 to 5.94, depending on the stage and virus type. The removal efficiency of bacterial pathogens was more than 99%. High throughput 18S rRNA gene amplicon sequencing indicated the dominance of animal parasitic Apicomplexa species and Vermamoeba spp. in the WSP. Network analysis indicated significant roles for Ciliophora in virus reduction. Notably, the maturation pond's outlet was dominated by Spirulina maxima, whose mat-forming tendencies may inhibit pathogen removal by providing protective shelters. Although the WSP effectively reduced pathogen levels, the high initial loads resulted in considerable concentrations in the final effluent, posing ongoing public health concerns. This study highlights the imperative of including pathogen standards in national regulations for wastewater reuse.

Assuring reclaimed water quality using a multi-barrier treatment train according to the new EU non-potable water reuse regulation

In this study, we evaluated the ability of various pilot-scale treatment train combinations to meet the microbial requirements of the new European non-potable water reuse regulation 2020/741. The study utilized non-disinfected secondary effluent from the wastewater treatment plant in Schweinfurt, Germany, as feedwater for two pilot-scale treatment trains. The first, a reference treatment train (Train A), consisted of filtration and UV disinfection as specified for reclaimed water class A in the EU regulation. The second, an advanced treatment train (Train B), included ceramic ultrafiltration (UF), ozonation, biological activated carbon filtration (BAC), and final UV disinfection. Based on a Monte Carlo simulation for Train A, the EU requirements for pathogen removal were not met when an average UV dose of 400-600 J m−2 was applied. This shortcoming was likely due to a moderate transmittance range (50–65 %), resulting in decreased UV fluence. These findings suggest that operational conditions for disinfection should be more clearly specified to ensure consistent pathogen inactivation both during validation and regular operation. In contrast, treatment train B successfully met the requirements of the EU regulations by reducing pathogens to below the detection limit. The UF membrane demonstrated a positive effect on the overall log reduction values (LRVs) throughout the water reclamation system. It also enhanced the efficiency of downstream processes, such as ozonation and UV disinfection, by lowering total suspended solids and turbidity. However, even without the UF membrane, treatment train B was still able to meet the pathogenic EU requirements for non-potable reuse applications. Furthermore, the study observed that the inclusion of biologically activated carbon (BAC) filtration requires a final disinfection step (e.g., UV disinfection) to prevent the potential occurrence of heterotrophic bacteria that proliferate in the BAC filter. For process validation it is recommended to use at least two different virus surrogates (MS2 and PhiX174), rather than just one or total coliphage as required in the EU regulation.

To Analysis the Necessity of Advance Sewage Treatment Plant (STP) Waste Management In Primary Health Care Centers (A Review)

The effluent from medical facilities poses a serious risk to human health because of how vulnerable people are to certain diseases. Additionally, the COVID-19 pandemic has called for a global awareness of the need to monitor infections and other resistant organisms in hospital wastewater and remove them. Apart from that, the presence of various resistant organics, pharmaceutically active compounds (PhACs), etc., creates a complicated pollution stack that affects biological systems and water resources. This survey has provided information on the occurrence, persistence, and removal of drug-resistant microbes, infectious diseases, and other micropollutants. The implementation of several pilot/full-scale measures has been evaluated with respect to the removal of pathogens, PhACs, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), etc. Many organic forms, including constructed wetlands, actuated slime handles, and film bioreactors, were discovered to provide more than 80% evacuation of BOD, COD, TSS, etc. Nevertheless, some stubborn natural toxins are not as amenable to such treatments and necessitate the use of tertiary drugs such adsorption, UV treatment, ozone treatment, and so forth. Following the treatment of clinic wastewater, antibiotic-resistant bacteria and illnesses were discovered to be very persistent, necessitating high dosages of chlorination or UV therapy to render them inactive. This project involves the Govthospital exectting STP supplanted by modern innovation STP.

Efficient water disinfection against antibiotic-resistant bacteria by visible-light heterogeneous photo-Fenton-like process with atomically dispersed Cu on graphitic carbon nitride as the catalyst

Waterborne microbial contamination poses significant environmental and health risks. Photocatalytic heterogeneous Fenton and Fenton-like processes can offer efficient pathogen removal, with benefits in recycling, solid–liquid separation, and byproduct avoidance. However, their low reaction efficiency and slow kinetics for low-valence metal regeneration are limitations. This study addresses these challenges by incorporating atomically dispersed Cu onto graphitic carbon nitride (g-CN) as a single-atom catalyst (SAC). The Cu atoms are stabilized by pyridinic N atoms through coordination, forming Cu-N4 catalytic sites that enhance photogenerated charge carrier transfer. This leads to a more efficient synergistic photocatalytic-Fenton-like reaction, generating more hydroxyl radicals and achieving effective water disinfection. Results show a 7-log bacterial inactivation of antibiotic-resistant Acinetobacter baumannii within 8 min, surpassing prior photocatalytic-Fenton-like disinfection systems. Density functional theory calculations confirm improved hydrogen peroxide adsorption, electron transport, and electron-hole separation in the Cu-N4 structure. The catalyst’s durability and stability were demonstrated through extensive cycling experiments, ion interference tests, and disinfection trials in various water matrices. Additionally, the Cu-SAC@CN catalyst, loaded onto a polytetrafluoroethylene membrane, achieved a 99% bacterial eradication rate within 20 min. This study provides valuable insights into the potential applications of heterogeneous photocatalytic-Fenton-like systems for efficient eradication of waterborne bacteria.

A mechanistic modeling and estimation framework for environmental pathogen surveillance

Environmental pathogen surveillance is a promising disease surveillance modality that has been widely adopted for SARS-CoV-2 monitoring. The highly variable nature of environmental pathogen data is a challenge for integrating these data into public health response. One source of this variability is heterogeneous infection both within an individual over the course of infection as well as between individuals in their pathogen shedding over time. We present a mechanistic modeling and estimation framework for connecting environmental pathogen data to the number of infected individuals. Infected individuals are modeled as shedding pathogen into the environment via a Poisson process whose rate parameter λt varies over the course of their infection. These shedding curves λt are themselves random, allowing for variation between individuals. We show that this results in a Poisson process for environmental pathogen levels with rate parameter a function of the number of infected individuals, total shedding over the course of infection, and pathogen removal from the environment. Theoretical results include determination of identifiable parameters for the model from environmental pathogen data and simple, explicit formulas for the likelihood for particular choices of individual shedding curves. We give a two step Bayesian inference framework, where the first step corresponds to calibration from data where the number of infected individuals is known, followed by an estimation step from environmental surveillance data when the number of infected individuals is unknown. We apply this modeling and estimation framework to synthetic data, as well as to an empirical case study of SARS-CoV-2 in environmental dust collected from isolation rooms housing university students. Both the synthetic data and empirical case study indicate high inter-individual variation in shedding, leading to wide credible intervals for the number of infected individuals. We examine how uncertainty in estimates of the number of infected individuals from environmental pathogen levels scales with the true number of infected individuals and model misspecification. While credible intervals for the number of infected individuals are wide, our results suggest that distinguishing between no infection and small-to-moderate levels of infection (≈10 infected individuals) may be possible, and that it is broadly possible to differentiate between moderate (≈40) and high (≈200) numbers of infected individuals.

Optimizing ozone treatment for pathogen removal and disinfection by-product control for potable reuse at pilot-scale

Reclaimed water poses environmental and human health risks due to residual organic micropollutants and pathogens. Ozonation of reclaimed water to control pathogens and trace organics is an important step in advanced water treatment systems for potable reuse of reclaimed water. Ensuring efficient pathogen reduction while controlling disinfection byproducts remains a significant challenge to implementing ozonation in reclaimed water reuse applications. This study aimed to investigate ozonation conditions using a plug flow reactor (PFR) to achieve effective pathogen removal/inactivation while minimizing bromate and N-Nitrosodimethylamine (NDMA) formation. The pilot scale study was conducted using three doses of ozone (0.7, 1.0 and 1.4 ozone/total organic carbon (O3/TOC) ratio) to determine the disinfection performance using actual reclaimed water. The disinfection efficiency was assessed by measuring total coliforms, Escherichia coli (E. coli), Pepper Mild Mottle Virus (PMMoV), Tomato Brown Rugose Fruit Virus (ToBRFV) and Norovirus (HNoV). The ozone CT values ranged from 1.60 to 13.62 mg min L−1, resulting in significant reductions in pathogens and indicators. Specifically, ozone treatment led to concentration reductions of 2.46–2.89, 2.03–2.18, 0.46–1.63, 2.23–2.64 and > 4 log for total coliforms, E. coli, PMMoV, ToBRFV, and HNoV, respectively. After ozonation, concentrations of bromate and NDMA increased, reaching levels between 2.8 and 12.0 μg L−1, and 28–40.0 ng L−1, respectively, for average feed water bromide levels of 86.7 ± 1.8 μg L−1 and TOC levels of 7.2 ± 0.1 mg L−1. The increases in DBP formation were pronounced with higher ozone dosages, possibly requiring removal/control in subsequent treatment steps in some potable reuse applications.

Vermifiltration as a green solution to promote digestate reuse in agriculture in small-scale farms

Digestates from low-tech digesters need to be post-treated to ensure their safe agricultural reuse. This study evaluated, for the first time, vermifiltration as a post-treatment for the digestate from a low-tech digester implemented in a small-scale farm, treating cattle manure and cheese whey under psychrophilic conditions. Vermifiltration performance was monitored in terms of solids, organic matter, nutrients, and pathogens removal efficiency. In addition, the growth of earthworms (Eisenia foetida) and their role in the process was evaluated. Finally, the vermicompost and the effluent of the vermifilter were characterized in order to assess their potential reuse in agriculture.Vermifilters showed high removal efficiency of chemical oxygen demand (55–90%), total solids (60–80%), ammonium nitrogen (83–97%), and phosphate-P (28–49%). Earthworms effectively grew and reproduced on digestate (i.e. earthworms number increased by 183%), enhancing the vermifiltration performance, while reducing clogging and odour-related issues. Both the vermicompost and effluent produced complied with legislation limits established for soil improvers and wastewater for fertigation, respectively. Indeed, there was an absence of pathogens and non-detectable heavy metals concentrations. Vermifiltration may be thus considered a suitable post-treatment option for the digestate from low-tech digesters, allowing for its safe agricultural reuse and boosting the circular bioeconomy in small-scale farms.

Utilizing Mixed Cultures of Microalgae to Up-Cycle and Remove Nutrients from Dairy Wastewater.

This study explores the novel use of mixed cultures of microalgae-Spirulina platensis, Micractinium, and Chlorella-for nutrient removal from dairy wastewater (DW). Microalgae were isolated from a local wastewater treatment plant and cultivated under various light conditions. The results showed significant biomass production, with mixed cultures achieving the highest biomass (2.51 g/L), followed by Spirulina (1.98 g/L) and Chlorella (1.92 g/L). Supplementing DW (75%) with BG medium (25%) significantly enhanced biomass and pH levels, improving pathogenic bacteria removal. Spirulina and mixed cultures exhibited high nitrogen removal efficiencies of 92.56% and 93.34%, respectively, while Chlorella achieved 86.85% nitrogen and 83.45% phosphorus removal. Although growth rates were lower under phosphorus-limited conditions, the microalgae adapted well to real DW, which is essential for effective algal harvesting. Phosphorus removal efficiencies ranged from 69.56% to 86.67%, with mixed cultures achieving the highest removal. Microbial and coliform removal efficiencies reached 97.81%, with elevated pH levels contributing to significant reductions in fecal E. coli and coliform levels. These findings suggest that integrating microalgae cultivation into DW treatment systems can significantly enhance nutrient and pathogen removal, providing a sustainable solution for wastewater management.