Disinfection Rate Research Articles

Comparative analysis of the SolWat photovoltaic performance regarding different PV technologies and hydraulic retention times

SolWat is a hybrid photovoltaic (PV) and photochemical technology, which integrating a PV module and a water disinfection reactor on top of it, was developed to meet the needs of safe drinking-water and electricity in developing countries. This paper assessed the effects of the water disinfection reactor on the electrical performance of the PV module integrated into the SolWat system regarding different hydraulic retention times (HRT) and PV technologies. With this aim, several tests were conducted outdoors under natural climatic conditions. Results showed that while no clear benefits were observed from the water disinfection reactor and reduced HRT on the electrical performance of both monocrystalline and multicrystalline technologies, the final energy output of a-Si thin film PV panels benefited from the cooling effect of water on its front surface being able to produce even more energy than a single PV panel when working at shorter HRT. In addition, the working module temperature was always lower when HRT was shorter; its efficiency under the diffuse light conditions created by the water disinfection reactor was better than monocrystalline and multicrystalline technologies; and its black surface enhanced the absorption of far infrared light and heat by the water disinfection reactor favouring higher water temperatures and thus higher disinfection rates. In conclusion, thin film PV technology is the most suitable to be integrated into the hybrid SolWat systems when comparing with monocrystalline and multicrystalline technologies.

Disinfection of urines using an electro-ozonizer

In this work, the disinfection of urines polluted with Klebsiella pneumoniae (K. pneumoniae) using a commercial electro-ozonizer is described. The device consists of a membrane-electrode assembly flow cell that specially promotes the electrochemical generation of ozone. Results show that a complete disinfection is attained in less than 180 min when working at current intensities higher than 0.5 A. The higher the current intensity, the higher the disinfection rate. Furthermore, the use of an electro-ozonizer for treating diluted urines leads to higher disinfection efficiencies. Ozone and chlorine-based disinfectants (hypochlorite and chloramines) were identified as the main oxidant species involved in killing bacteria. The combined effect of all disinfectants promotes higher removal efficiencies in comparison with the single effect of ozone evaluated in a urine matrix without chlorides, being more remarkable at lower current intensities. The crystal violet assay showed that cell wall is damaged by the electrogenerated oxidants and it is more remarkable by the combined effect of ozone and chlorine disinfectants when increasing the current intensity. Finally, the degradation of total proteins and genetic material (DNA) were also monitored and related to the oxidants produced during the electrochemical process.

Disinfection characteristics of an advanced rotational hydrodynamic cavitation reactor in pilot scale

Hydrodynamic cavitation is a promising technique for water disinfection. In the present paper, the disinfection characteristics of an advanced hydrodynamic cavitation reactor (ARHCR) in pilot scale were studied. The effects of various flow rates (1.4–2.6 m3/h) and rotational speeds (2600–4200 rpm) on the removal of Escherichia coli (E. coli) were revealed and analyzed. The variation regularities of the log reduction and reaction rate constant at various cavitation numbers were established. A disinfection rate of 100% was achieved in only 4 min for 15 L of simulated effluent under 4200 rpm and 1.4 m3/h, with energy efficiency at 0.0499 kWh/L. A comprehensive comparison with previously introduced HCRs demonstrates the superior performance of the presented ARHCR system. The morphological changes in E. coli were studied by scanning electron microscopy. The results indicate that the ARHCR can lead to serious cleavage and surface damages to E. coli, which cannot be obtained by conventional HCRs. Finally, a possible damage mechanism of the ARHCR, including both the hydrodynamical and sonochemical effects, was proposed. The findings of the present study can provide strong support to the fundamental understanding and applications of ARHCRs for water disinfection.

Magnetic g-C3N4/NiFe2O4 composite with enhanced activity on photocatalytic disinfection of Aspergillus flavus

Aspergillus flavus can cause crop loss and produce mycotoxin that bring serious threats to human health. The large usage of chemical pesticides or fungicides might cause environmental problems and fungal resistance. Therefore, developing the novel, low possibility of resistance and pro-environment way to control and reduce this fungi is meaningful. Herein, an efficient, environmental-friendly and photocatalytic method to disinfect Aspergillus flavus was demonstrated on magnetic and Z-schematic composites. The composites were composed of rhombic NiFe2O4 nanosheets and g-C3N4 nanosized sheets, and 0.2 g-C3N4/NiFe2O4 (mass ratio) showed the excellent activity with above 90% disinfection rate under 90 min visible light irradiation. The efficient disinfection activities were ascribed to the favorable charges separation, well photoelectric properties and suitable band structure. It was found that the •O2− and •OH were the main active radical species in photocatalytic disinfection. The attack of these species could cause the destruction of fungal cell structure and the leakage of intracellular contents as proved by the fluorescence staining of spores, biological scanning electron microscope and the detection of extracellular protein and DNA. Moreover, the composites also showed high photocatalytic disinfection activity of Aspergillus flavus on peanuts, which can reduce aflatoxin B1 from 315.21 µg kg−1 to 18.50 µg kg−1. This efficient method might be considered as a potential way to control the contamination of Aspergillus flavus, and as a reference to the mitigation of other pathogenic fungi in future.

Variables Affecting the Recovery of Acanthamoeba Trophozoites.

While the results of Acanthamoeba testing have been extensively published, laboratories conducting such testing are left to develop their own methods in the absence of a standardized methodology. The wide disparity of methods has resulted in equally inconsistent reported results for contact lens care (CLC) products. This study’s objective was to determine the source of these discrepancies by evaluating basic Acanthamoeba biology and their impact on antimicrobial efficacy testing, including the ability of a recovery method to stimulate a single trophozoite to proliferate. Antimicrobial efficacy testing was conducted using well-published Acanthamoeba strains, storage conditions, and growth-based recovery methods. To identify variables that influence results, test solutions with low Acanthamoeba disinfection rates were utilized to prevent differences from being masked by high log reductions. In addition, single-cell proliferation assays were executed to understand the growth requirements to stimulate trophozoite propagation in two recovery methods. These studies indicated that both nutrient density (>106 CFU) and the length of plate incubation (at least 14 days) could significantly influence the accurate recovery of trophozoites. Together, this study emphasizes the need to understand how Acanthamoeba trophozoites biology can impact test methods to create divergent results.

The photocatalytic antibacterial behavior of Cu-doped nanocrystalline hematite prepared by mechanical alloying

To improve the photocatalytic properties of hematite (Fe2O3), we take the merit of nanoscale and exploit a mechanical alloying (MA) method for Cu doping with various weight percentages (1, 3, 5, and 10). Our techniques to evaluate the phase and morphological characterization of the prepared nanoparticles were, respectively, X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The elemental analysis and elemental distribution map were examined by energy dispersive X-ray spectroscopy (EDS). Furthermore, we utilized Fourier transform infrared (FTIR) analysis and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS) for appraisal of Fe–O and Cu–O bonds and band gaps. Then we investigated the photocatalytic activity based on methylene blue (MB) photodegradation under irradiation of 300 W Xenon lamp and finally explored the antibacterial behavior against Escherichia coli (E. coli). The UV–Vis DRS results indicated reduction of band gap in the Cu-doped hematite nanoparticles. For the samples considered here, the sample with 5 wt.% of the dopant showed the lowest band-gap, 1.57 eV. It also decomposed 92.5% of MB from the wastewater under the Xenon-lamp irradiation during 120 min, and had the highest rate of disinfection with > 99.99% of bacterial removal in 360 min. Low band gap, substantial sunlight absorption, efficient MB removal, and high antibacterial activity are some suitable photocatalytic properties specifically achieved in this work.

Comparison of disinfectants for drinking water: chlorine gas vs. on-site generated chlorine

The feasibility of on-site generated chlorine (OSG chlorine) as an alternative disinfectant to chlorine gas was evaluated in terms of total organic carbon (TOC) removal, disinfection efficiency, biofilm control, disinfection by-products (DBPs) formation, chlorine decay rate, and volatility. Chlorine gas decreased the pH of the treated water by -0.1 per mg/L of free available chlorine (FAC) while OSG chlorine increased the pH by + 0.06 per mg/L. OSG chlorine with more hypochlorite ion (OCl-) at higher pH was less effective in the inactivation of suspended bacteria and TOC removal but remained in the distribution system longer and controlled biofilm formation more effectively than chlorine gas. The DBPs formation by OSG chlorine was not significantly different from that by chlorine gas except for the reduction of Haloacetonitriles. Hypochlorous acid (HOCl) was more volatile than OCl-, indicating the lower volatility of FAC in the OSG chlorine-treated water. Two types of OSG systems, “Mixed oxidants” and OSG hypochlorite, did not show any significant difference in disinfection, DBPs formation, and chlorine decay rate (paired t-test, p = 0.40, 0.11 ~ 0.70, > 0.42). A significant synergy effect by oxidants other than FAC cannot be expected in the use of “mixed oxidants” at a water treatment plant.

Pseudoviruses for the assessment of coronavirus disinfection by ozone.

The COVID-19 pandemic has severely impacted public health worldwide. Evidence of SARS-CoV-2 transmission via aerosols and surfaces has highlighted the need for efficient indoor disinfection methods. For instance, the use of ozone gas as a safe and potent disinfectant against SARS-CoV-2 virus is of particular interest. Here we tested the use of pseudoviruses as a model for evaluating ozone disinfection of the coronavirus at ozone concentrations of 30, 100, and 1000 ppmv. Results show that ozone disinfection rate of pseudoviruses was similar to that of coronavirus 229E (HuCoV-229E) at short contact times, below 30 min. Viral infection decreased by 95% following ozone exposure for 20 min at 1000 ppmv, 30 min at 100 ppmv and about 40 min at 30 ppmv. This findings mean that ozone is a powerful disinfectant toward the enveloped pseudovirus even at low ozone exposure. We also showed that viral disinfection occurs on various contaminated surfaces, with a positive association between disinfection and surface hydrophilicity. Infected surfaces made of aluminum alloy, for example, were better disinfected with ozone as compared to brass, copper, and nickel surfaces. Lastly, we demonstrate the advantage of ozone over liquid disinfectants by showing similar viral disinfection on top, side, bottom, and interior surfaces. Overall, our study demonstrates the potential use of ozone gas disinfection to combat the COVID-19 outbreak.Electronic supplementary materialThe online version of this article (10.1007/s10311-020-01160-0) contains supplementary material, which is available to authorized users.

Photoelectrocatalytic degradation of humic acid and disinfection over Ni TiO2-Ni/ AC-PTFE electrode under natural sunlight irradiation: Modeling, optimization and reaction pathway

NiTiO2NT and TiO2 nanotube-based photoelectrodes were prepared by anodic oxidation and employed for the degradation of humic acid (HA) and disinfection simultaneously by the photoelectrocatalytic (PEC) process under natural sunlight irradiation. Scanning electron microscopy coupled with energy-dispersive spectroscopy (EDX) studies confirmed that uniform nanotubes TiO2 covered all surface of Ti foil and Ni doped to TiO2NT. The highest efficiency for HA degradation and disinfection rate by PEC was observed for the NiTiO2NT photoelectrode. The influences of different parameters such as initial HA concentration (2–8 mg/L), voltage (2–20 V), bacterial density (2 × 102,104,107 CFU), time (30–60 min), light source (UV–Vis) and type of electrode (NiTiO2NT/AC-PTFE, TiO2NT/AC-PTFE) on disinfection of water and degradation of the HA were studied using response surface methodology (RSM). The results showed that the maximum degradation rate of HA and Log bacterial removal reached 87.18% and 3.77 after 60 min reaction time at a 20 V voltage with NiTiO2NT/AC-PTFE electrode and UV as a source of irradiation. Also, results showed that doping Ni to TiO2NT electrode increase PEC efficiency under Vis-light source. To determine the HA degradation pathway, the organic byproducts were identified by GC–MS analysis.

Effect of TiO2 Loading, Water Depth and Light Intensity on Photo-Disinfection Efficacy of Escherichia Coli O157:H7 Using TiO2 NP-Embedded Cellulose Acetate Film in Water

HighlightsPhoto-disinfection using TiO2 NP-embedded CA film showed great potential.TiO2 loading, water depth, and light intensity affected TiO2 photo-disinfection.Bacterial reduction can be predicted based on water depth and light intensity.Durability of the TiO2 NP-embedded CA film has been demonstrated.Abstract. Photocatalysis disinfection has great potential for food and water safety applications. TiO2 NP-embedded cellulose acetate (CA) film has shown effectiveness in inactivating Escherichia coli (E. coli) O157:H7 in water. This study evaluated the effect of several operational parameters such as TiO2 load, light intensity, and water depth on photo-disinfection efficacy of TiO2 NP-embedded CA film. Effect of TiO2 load on photocatalysis disinfection efficacy was investigated by assessing the disinfection rate of the films at different TiO2 levels in inoculated water at a weak UV-A light intensity. The individual and interaction effects of light intensity and water depth on photocatalysis disinfection were evaluated using the response surface methodology (RSM). Based on a central composite design, 13 runs of experiments were conducted with the combination of the two factors at three levels. The effect of film size on photo-disinfection efficacy was also investigated. Results showed that CA film with a TiO2 load of 0.82 mg/cm2 yielded the highest disinfection rate. An empirical model was established to predict the effect of light intensity and water depth on bacterial reduction with a high coefficient of determination (R2 = 0.98). An increased water depth or a decreased light intensity reduced photo-inactivation efficacy. A 5 log reduction was achieved during a 3-h treatment at a light intensity of 1 mW/cm2 and water depth at 1.6 cm. The photo-disinfection efficacy of the film was not significantly (p>0.05) affected by film size. The CA film was able to maintain antimicrobial efficacy after four repeated uses. Results from this study demonstrated that UV-A assisted photo-disinfection using TiO2 NP-embedded CA film has great potential to inactivate pathogens in water. Keywords: Cellulose Acetate, E. coli O157:H7, Photocatalysis, TiO2 nanoparticles, Water Treatment.

Efficacy of Laser Photoacoustic Streaming in Paediatric Root Canal Disinfection - An Ex-Vivo Study.

Background:Various techniques have been employed to enhance the root canal disinfection rate using sodium hypochlorite (NaOCl) as an irrigant. Photon initiated photo-acoustic streaming using lasers is a newer method of endodontic disinfection.Aim:The aim of this study is to evaluate and compare the efficacy of photo-initiated photoacoustic streaming and conventional irrigation technique using 2.5% NaOCl for root canal disinfection in primary teeth.Setting and Design:Laboratory setting and ex-vivo design.Materials and Methods:Twenty extracted primary teeth were selected in which Enterococcus faecalis incubation was done in the root canals and bacterial counts were obtained before the intervention. The teeth were randomly allocated into two groups. Group I samples were irrigated with conventional syringe method using 2.5% NaOCl and Group II samples were irrigated using photon-initiated photo-acoustic streaming method with erbium-doped yttrium aluminum garnet laser (wavelength - 2940 nm). Postintervention samples were obtained, and bacterial colony count was done. Wilcoxon Signed- Ranks Test and Mann–Whitney test were applied to test the intragroup and intergroup differences in the bacterial counts. Results:Postintervention results showed no bacterial growth in the canals irrigated using Laser (P = 0.004) whereas, fewer bacterial colonies were observed in NaOCl group (P = 0.005). There was statistically significantly higher reduction in E. faecalis counts in Laser Activated irrigation (LAI) group compared to NaOCl group (P < 0.05).Conclusion:Total elimination of E. faecalis counts was obtained by the use of laser activated NaOCl irrigation in the infected root canals, hence, it can be considered as an effective method for pediatric endodontic disinfection.

821. Portable Medical Equipment Disinfection: How often does it occur?

BackgroundPortable Medical Equipment (PME) are routinely used by healthcare workers (HCWs). Transmission of healthcare-acquired infections has been attributed to PME. Our institution policy requires at least once daily PME disinfection. Automated tracking of disinfection events by Disinfection Tracking System (DTS) makes routine monitoring possible. We tested the device to see if it could provide accurate information about disinfection practices and patterns, as well as be used to accurately monitor compliance with policy.MethodsData obtained from DTS devices on PME from 2 acute care wards over a 25-day period was obtained. DTS devices record disinfection events and are automatically stored for monitoring. DTS was placed on 10 computer-on-wheels (COWs) and 5 vitals machine (VMs) on both the wards. One ward received DTS with “Screen-on” feedback displaying the time since last disinfection event, and one unit had no display on the screen (screen-off). The number of recorded events was summed over the 25-day period and sorted by time of day to determine the pattern of events over a typical 24-hour period. Minute “0” indicates start of each monitoring period in a 24-hour cycle and corresponds to 12 midnight (Figure 1).ResultsA total of 421 moisture events were recorded for the screen-on and 345 for the screen-off, during the 25-day implementation period. The highest number of events occurred between 6am and 7am, with 69 moisture events recorded in the screen-on group and 75 events were recorded for the screen-off group. Further, 37 events were recorded in the screen-on group and 43 events in the screen-off group between 2pm and 3pm. Between 6pm and 7pm the screen-on group showed 52 moisture events and 32 events for the screen-off group. Figures 1 shows the three peaks corresponding with a spike in disinfection events.ConclusionThe pattern of disinfection events over 24 hours demonstrate that most events occurred regularly at certain times in the day. These time points correspond with higher volumes of disinfection happening at the beginning of shift changes for nursing. It also demonstrated that disinfection rates were higher than the policy recommended once a day PME disinfection. DTS has the potential to continuously record & report data related of disinfection events on PME in healthcare settings.Disclosures Chetan Jinadatha, MD, MPH, AHRQ (Research Grant or Support)Department of Veterans Affairs (Other Financial or Material Support, Owner: Department of Veterans Affairs. Licensed to: Xenex Disinfection System, San Antonio, TX)Inventor (Other Financial or Material Support, Methods for organizing the disinfection of one or more items contaminated with biological agents)NiH/NINR (Research Grant or Support)NSF (Research Grant or Support)Xenex Healthcare Services (Research Grant or Support) Mark Stibich, PhD MHS, Xenex Disinfection Services, Inc (Board Member, Employee) Sarah Simmons, DrPH, Xenex Disinfection Services (Employee, Shareholder)

Mathematical modeling of E. coli inactivation in water using Fe-TiO2 composite in a fixed bed reactor

An inexpensive Fe-TiO2 composite fabricated via mixing clay with foundry sand (FS) and fly ash (FA), for the in-situ disinfection of E. coli. The continuous leaching of iron at acidic conditions into the solution through the composite and the TiO2 photoactivity on the surface of Fe-TiO2 composite beads exhibited an in-situ dual effect of photocatalysis and photo-Fenton in the treatment system. In this research work comparison of five different processes (UV irradiation; H2O2 with UV irradiation; TiO2 assisted photocatalytic technique; photo-Fenton and dual-technique (photocatalysis + photo-Fenton) using three different kinetic models were done. Kinetic studies showed more than 2 times of increase in the reaction rate with a log reduction of 6.4 only in 90 min of treatment time, thus proves the faster rate of disinfection. 18% of synergy was observed with dual effect over photocatalysis and photo-Fenton. The composite beads were recycled 30 times and only 11% reduction in the photoactivity of the catalyst was observed. Thus the obtained results present a promising potential of the dual technology for the treatment of E. coli in water.

A journey of wastewater to clean hydrogen: A perspective

A journey of wastewater to clean hydrogen: A perspective

Quality monitoring analysis of disinfection effectiveness in medical institutions in Shenzhen, 2015-2019

Objective To master the disinfection effect of medical institutions at different levels in Shenzhen, and we provide scientific basis for improving the quality of disinfection and reducing hospital-acquired infections. Methods According to the relevant standards, the quality of disinfection in medical institutions in Shenzhen city from 2015 to 2019 was continuously monitored by filed sampling and experimental testing. Results From 2015 to 2019, a total of 139 025 samples were collected form medical institutions in Shenzhen, of which 133 714 samples were qualified, and the qualified rate was 96.18%. The qualified rates for disinfection in 2015-2019 were 96.34%, 95.06%, 95.78%, 96.06%, 97.64%, respectively. The qualified rate increased year by year from 2016, and the difference was statistically significant ( P <0.001). Among all the monitoring items, the qualified rate of therapeutic water was the highest at 100.00%. The qualified rate ultraviolet lamp was the lowest at 91.75%. The qualified rate of private and individual clinics was 95.40%, which was lower than that of primary (98.48%), secondary (98.17%) and tertiary (97.84%) medical institutions ( P <0.05). Conclusion The overall quality of disinfection in medical institutions in Shenzhen is good, but the qualified rate of air, sanitary hand and ultraviolet lamp is low, and qualified rate of disinfection in private and individual clinics varies considerably over a five-year period, requiring further strengthening of supervision and management. 摘要：目的 掌握深圳市各级医疗机构消毒效果,为提髙消毒质量,减少院内感染提供科学依据。 方法 依据相 关标准,通过现场采样和微生物检验方法,对深圳市2015—2019年医疗机构消毒质量进行连续监测。 结果 深圳市 2015—2019年医疗机构共采样139 025件,合格样品133 714件,合格率96.18%。2015—2019年消毒合格率分别为 96.34%、95.06%、95.78%、96.06%、97.64%,从2016年开始合格率逐年上升,差异有统计学意义( P <0.001)。各监测项目 中,治疗用水合格率最髙,为100.00%;紫外线灯合格率最低,为91.75%。私营医疗机构及个体诊所合格率为95.40%, 三级医疗机构消毒合格率为97.84%、二级为98.17%,一级为98.48%,不同级别医疗机构消毒合格率差异有统计学意义 ( P <0.05)。其中,三级医疗机构手卫生和消毒后内镜消毒合格率偏低,私营及个体诊所空气和手卫生消毒合格率最低。 结论 深圳市医疗机构消毒质量整体较好,但空气、手卫生、紫外线灯消毒合格率较低,私营及个体诊所5年内消毒合 格率变化幅度较大,需要进一步加强监督管理。

Tomato Brown Rugose Fruit Virus: Seed Transmission Rate and Efficacy of Different Seed Disinfection Treatments.

Tomato brown rugose fruit virus (ToBRFV) is a highly infectious virus, that is becoming a threat to tomato production worldwide. In this work we evaluated the localization of ToBRFV particles in tomato seeds, its seed transmission rate and efficacy of disinfection, and the effects of different thermal- and chemical-based treatments on ToBRFV-infected seeds’ germination. Analyses demonstrated that ToBRFV was located in the seed coat, sometime in the endosperm, but never in the embryo; its transmission from infected seeds to plantlets occurs by micro-lesions during the germination. The ToBRFV seed transmission rate was 2.8% in cotyledons and 1.8% in the third true leaf. Regarding the different disinfection treatments, they returned 100% of germination at 14 days post-treatment (dpt), except for the treatment with 2% hydrochloric acid +1.5% sodium hypochlorite for 24 h, for which no seed germinated after 14 dpt. All treatments have the ability to inactivate ToBRFV, but in six out of seven treatments ToBRFV was still detectable by RT-qPCR. These results raise many questions about the correct way to carry out diagnosis at customs. To our knowledge, this is the first study on the effective localization of ToBRFV particles in seeds.

Predicting airborne coronavirus inactivation by far-UVC in populated rooms using a high-fidelity coupled radiation-CFD model

There are increased risks of contracting COVID-19 in hospitals and long-term care facilities, particularly for vulnerable groups. In these environments aerosolised coronavirus released through breathing increases the chance of spreading the disease. To reduce aerosol transmissions, the use of low dose far-UVC lighting to disinfect in-room air has been proposed. Unlike typical UVC, which has been used to kill microorganisms for decades but is carcinogenic and cataractogenic, recent evidence has shown that far-UVC is safe to use around humans. A high-fidelity, fully-coupled radiation transport and fluid dynamics model has been developed to quantify disinfection rates within a typical ventilated room. The model shows that disinfection rates are increased by a further 50-85% when using far-UVC within currently recommended exposure levels compared to the room’s ventilation alone. With these magnitudes of reduction, far-UVC lighting could be employed to mitigate SARS-CoV-2 transmission before the onset of future waves, or the start of winter when risks of infection are higher. This is particularly significant in poorly-ventilated spaces where other means of reduction are not practical, in addition social distancing can be reduced without increasing the risk.

Enhancement of UV disinfection of urine matrixes by electrochemical oxidation

This work focuses on the removal of antibiotic-resistant bacteria (ARB) contained in hospital urines by UV disinfection enhanced by electrochemical oxidation to overcome the limitations of both single processes in the disinfection of this type of effluents. UV disinfection, electrolysis, and photoelectrolysis of synthetic hospital urine intensified with K. pneumoniae were studied. The influence of the current density and the anode material was assessed on the disinfection performance of combined processes and the resulting synergies and/or antagonisms of coupling both technologies were also evaluated. Results show that the population of bacteria contained in hospital urine is only reduced by 3 orders of magnitude during UV disinfection. Electrolysis leads to complete disinfection of hospital urine when working at 50 A m−2 using Boron Doped Diamond (BDD) and Mixed Metal Oxides (MMO) as anodes. The coupling of electrolysis to the UV disinfection process leads to the highest disinfection rates, attaining a complete removal of ARB for all the current densities and anode materials tested. The use of MMO anodes leads to higher synergies than BDD electrodes. Results confirm that UV disinfection can be enhanced by electrolysis for the removal of ARB in urine, considering both technical and economic aspects.

Disinfection treatments eliminated tomato brown rugose fruit virus in tomato seeds

Tomato brown rugose fruit virus (ToBRFV), belonging to the genus Tobamovirus, is a highly-virulent emerging virus species, causing disease outbreaks and significant crop losses worldwide. No effective measure has been identified to control ToBRFV infection. Therefore, the objectives of this study were to investigate the effectiveness of three seed disinfection treatments on the elimination of ToBRFV in tomato seeds and their effect on seed quality. Seeds extracted from ToBRFV-infected fruits were treated with 2% hydrochloric acid (HCl) for 30 min, 10% trisodium phosphate (TSP) for 3 h, dry heat at 72 °C for 72 h, or their combinations; then, the seeds were tested for the presence of the virus using serological, molecular, and biological assays. Parallel treatments of seeds in distilled water (hydropriming) or untreated seeds were included for comparison. The quality of the treated seeds was also evaluated in terms of seed standard germination, mean time to germination (MTG), and seedling growth. Seeds extracted from ToBRFV-infected fruits had a 100% contamination rate. Treatment of ToBRFV-contaminated seeds with 2% HCl for 30 min or 10% TSP for 3 h resulted in a 100% disinfection rate, while heat treatment at 72 °C for 72 h or hydropriming treatments resulted in a 0% disinfection rate. Furthermore, seed treatment with HCl or hydropriming for 3 h significantly improved seed germination percentage, reduced MTG (faster speed of germination), and increased seedling length. In conclusion, seed treatment with 2% HCl for 30 min not only resulted in a 100% disinfection rate of seeds from the ToBRFV but also improved seed quality of tomato compared to untreated seeds.

Suspended and polycaprolactone immobilized Ag @TiO2/polyaniline nanocomposites for water disinfection and endotoxin degradation by visible and solar light-mediated photocatalysis.

In the present study, water contaminated with Escherichia coli (E. coli) cells was photocataytically disinfected using Ag core-TiO2 shell/Polyaniline nanocomposite (Ag@TiO2/PANI) under visible light irradiation. Ag@TiO2/PANI containing 13 weight % of Ag@TiO2 was found to offer maximum disinfection activity. Band gap energy of Ag@TiO2/PANI was found to be 2.58 eV. Ag@TiO2/PANI nanocomposites were efficient in water disinfection in their suspended and immobilized form. Rate of disinfection with Ag@TiO2/PANI was faster than that with Ag@TiO2 nanoparticles. Water containing 50 × 108 CFU/mL cells was completely disinfected within 120 min with 1 g/L Ag@TiO2/PANI nanocomposite. Simultaneous disinfection and endotoxins degradation were achieved. The photocatalytic disinfection of water and endotoxin degradation using Ag@TiO2/PANI nanocomposite under visible light irradiation followed second order kinetics. The nanocomposite also exhibited a good solar photocatalytic activity.