Rinse Water Research Articles

Layer transfer of ultrathin Ge crystal segregated on Al/Ge(111) structure

Effects of the surface modification by O2 plasma exposure on the Al/Ge(111) structure have been investigated in order to get an insight into a layer transfer technique of the ultrathin Ge layer segregated on the Al/Ge(111) structure toward the device fabrication, and then the wafer bonding of the Al/Ge(111) structure to the thermally-grown SiO2/Si structure has been demonstrated. The O2 plasma treatment and the subsequent pure water rinse were found to be effective to form the hydrophilic surface of the Al/Ge(111) structure with a suppression of the segregated Ge layer oxidation. The Al/Ge(111) structure with the hydrophilic surface was then bonded to the SiO2/Si substrate, and its bonding strength was enough to perform Ge thinning by the chemical mechanical polishing and the wet-chemical etching using H2O2-based solutions. Ohmic contact of the ring-type device pattern with the segregated Ge/Al stack was achieved by using the remaining p-type Ge substrate as the contact pads.

Understanding the processes of thickening and filtration of yellow cake slurry (ammonium polyuranate) generated by in-situ uranium leaching sites

One of the key stages in the in-situ leaching of uranium includes thickening of yellow cake slurry to obtain washed uranium concentrate. Russian in-situ leaching sites tackle this by using membrane filter presses. In spite of their high performance, filter presses have one major drawback – the filtration is done periodically. This paper describes the results of a laboratory study suggesting that, together with membrane filter presses, continuous band vacuum filters could also be used in this application. The yellow cake slurry obtained after precipitation of ammonium polyuranate from Dalur JSC’s eluates has the density of 1060–1065 kg/m3. In laboratory conditions, the slurry was thickened by adding 1 g/dm3 of Praestol 2530 slurry. The settling rate was 5.4 m/h, the thickening performance – 2.8 t/(m2.day). The resultant thickened product with a density of 1600 kg/m3 was filtered in a band filter with a three-stage counter-current washing cycle at a fresh water flow rate of 1 m3/t solid and a vacuum of –49 kPa. The process resulted in an average filtration performance of 8–9 t/(m2.day) and a 17–18 mm thick washed precipitate with 41–43% humidity. The duration of the overall filtration and washing cycle was 110–140 sec. The maximum concentration of sulphate-ion in the washed and dried yellow cake precipitate did not exceed 2.0%, which is significantly lower than the 4% allowed. It is noted that, if necessary, these indicators can be improved by raising the rinse water flow rate.

Enhancing cleaning of microfiltration membranes fouled by food oily wastewater using microbubbles

Food processing generates wastewater containing high contents of fat, oil and grease. As a widely used wastewater treatment method, the process efficiency of membrane filtration can be hindered by membrane fouling, hence periodic cleaning is needed. However, clean-in-place (CIP) operations performed in food processing plants consume large amounts of water, energy, and chemicals. This study incorporated microbubbles (MBs) with the mean diameter of 4.48 µm into liquids at the density of 1431 bubbles/mL as alternative cleaning agents, and investigated their performance of cleaning microfiltration membranes used for food oily wastewater treatment. Palm oil-in-water emulsions were used as model wastewater, increasing the oil concentration from 0.05 to 0.1% w/v changed the dominant fouling mechanism from intermediate blocking to cake formation. MB incorporation into water rinse did not recover the flux of membranes fouled with reversible oil layer, but adding MBs into NaOH solution for cleaning increased the flux recovery by 235%. Increasing the crossflow velocity of MB-incorporated liquids from 0.65 to 0.92 m/s reduced their enhancing effect on cleaning, but further increase to 1.20 m/s had the highest level of enhancement. Moreover, MBs did not significantly enhance the removal of oil deposits irreversibly blocking the membrane pores. MB-assisted cleaning proved a promising technology for integration into current CIP operations to improve their cleaning efficiency with reduced water and chemical usage.

Performance influence of polyacrylic acid dispersant on nuclear grade anion exchange resin

Secondary circuit water chemistry control is vital for the safe operation of nuclear power plants. Polyacrylic acid (PAA) is used in the secondary circuit water system to reduce the fouling of the steam generator (SG) because of its good dispersion effect. However, PAA as a macromolecular organic matter possibly causes organic fouling for anion exchange resin of the water purification system and affects its performance. Some research reported that the performance of resin changes after PAA application. But it is not clear whether this change is related to PAA. In this research, the anion resins were performed for five cycles, and each cycle included batch PAA adsorption, dynamic PAA desorption and resin rinse. Results showed that NaOH solution could realize the desorption of PAA on anion resin, but desorption solution and rinse water consumption slightly increased with the cycle number. Meanwhile, residual PAA linearly increased with the cycle number, but the rate was relatively slow. Furthermore, the performance influence of PAA on anion resin was investigated. The exchange capacity and kinetic performance for anion resin slightly decreased after PAA cycle. The effluent conductivity of anion resin bed increased after PAA cycle, but it could not cause the adverse influence of sodium leakage. The contrast experiment of H2SO4 cycle showed that resin aging was the primary reason for the change of resin performance, rather than residual PAA. Within the fewer cycles, PAA and anion resin had better compatibility.

Complete Genome Sequences of Two Salmonella enterica Strains Isolated from Chicken Carcass Rinse Water in Thailand.

We report the circularized complete genome sequences, containing a circular chromosome and two circular plasmids, of strains SalSpp05 (4.9 Mbp) and SalSpp10 (4.8 Mbp), which were isolated from chicken carcass rinse water samples; the sequences were obtained by combining Oxford Nanopore Technologies long-read data and Illumina short-read data. Whole-genome alignments indicated that both strains belong to Salmonella enterica.

In vitro Degradation of Profenofos by Rice Grain Rinse Water Lactic Acid Bacteria (LAB)

Widely used in fermentation industry, lactic acid bacteria (LAB) are not only probiotic but also capable of degrading pesticides. We evaluated in the laboratory degradation of profenofos 50% EC by the LAB present in rice grain rinse water cultured in LAB-specific de Mann Rogosa Sharpe (MRS) medium. A single colony of the isolated LAB was inoculated in MRS broth, kept in shaker for 24 h before 10 ml broth was transferred to 25 ml test tube inoculated with profenofos 50% EC at 1 ppm and checked 24, 48 and 72 h after inoculation for its residue by liquid-liquid extraction and gas chromatographic analysis. The results revealed that profenofos concentration decreased to 0.75, 0.44 and 0.25 ppm at 24, 48 and 72h, respectively, indicating the degradation of profenofos by the rice rinse water LAB.

Surface-enhanced Raman spectroscopy hair analysis after household contamination.

Trace evidence found at crime scenes is rarely in an unsullied condition. Surface-enhanced Raman spectroscopy (SERS) is a modern analytical technique that can be used for the detection of artificial hair colourants (S. Higgins and D. Kurouski, Surface-Enhanced Raman Spectroscopy Enables Highly Accurate Identification of Different Brands, Types and Colors of Hair Dyes, Talanta, 2022, 251, 123762). However, contaminants pose a problem to collecting accurate spectra from the dyes. In this study, we sought to analyze how the different physical properties of contaminants can influence the collected spectra. We utilized 11 household substances of varying viscosity and opacity to contaminate hair dyed with permanent black or semi-permanent blue dyes. We discovered that contaminant opacity generally does not affect the spectral quality but that high contaminant viscosity does and that acidic substances could destroy the colourant's spectral identity altogether. Cleaning the contaminated hair with a water rinse allowed the underlying colourant to be identified in 21 out of 22 cases. Overall, this study provided a clearer understanding of the capabilities and limitations of SERS in forensic hair analysis.

Effect of Different Decontamination Protocols Applied to Blood-Saliva Contaminated Dentin Surfaces of Universal Adhesive Resin Post-Etch on Shear Bond Strength

ABSTRACT This study was performed to evaluate the effect of different decontamination protocols applied to contaminated surfaces on the recovery of adhesion. Different decontamination protocols were applied to molar teeth contaminated with blood and saliva except the control group. 40 third molar teeth were divided into groups according to the applied decontamination protocols: Group 1(control), Group 2 (water rinse), Group 3 (15-sec re-etch), Group 4 (10-sec re-etch), Group 5 (5-sec re-etch), Group 6 (5% NaOCl), Group 7 (2% chlorhexidine gluconate), Group 8 (ozonated water). Universal adhesive resin (Gluma Universal, Heraus Kulzer) was used in the etch and rinse mode according to the manufacturer’s instructions. Nanohybrid composite material was placed in all groups. Then the Shear Bond strengths of all groups were evaluated after applying 5000 thermal cycles (5–55 °C) to each sample. In the limitation of this in vitro study, it has been shown that rinsing with ozonated water of contaminated surfaces with blood and saliva after etching, has increased the micro-shear bond strength (μSBS) values more than that of in control group values. Also, the application of NaOCl, re-etching with 37% phosphoric acid for 15 seconds, and cleaning with CHX, significantly increase the bonding potential.

The effect of dairy proteins on the oral burn of capsaicin.

This study focused on the effect of binding of capsaicin by milk proteins on oral burn. The concentration of free, unbound capsaicin in 5ppm capsaicin solution containing 0-5% (w/w) micellar casein or whey protein isolate was measured by extraction into hexadecane. The concentration of free capsaicin decreased linearly with protein concentration and the decrease was greater for casein than for whey protein. The intensity of the capsaicin burn in similar solutions was assessed by a large cohort (n=89) of untrained participants in a time-intensity study. The maximum burn intensity decreased with protein concentration and was lower for samples containing casein than for samples containing whey protein isolate. The maximum burn was linearly related to the free, unbound capsaicin concentration. When protein solutions (1-5% w/w) were used as rinses following exposure to a 5ppm aqueous capsaicin solution, only the 5% (w/w) micellar casein solution was significantly more effective than the water rinse in reducing oral burn.

First detection and low prevalence of Pearsonema spp. in wild raccoons (Procyon lotor) from Central Europe.

The urinary bladder and lower urinary tract of domestic and wild carnivores can be parasitised by filamentous nematodes from the genus Pearsonema (syn. Capillaria). Infestations are often asymptomatic, but severe courses in dogs and cats have been described. Hosts are infested through the ingestion of earthworms (Lumbricidae) which act as intermediate hosts. Epidemiological studies of Pearsonema in raccoons (Procyon lotor) in North America are scarce and previous studies of urinary bladder parasites of European raccoons did not provide evidence of infestation. We examined urine sediment or rinse water from urinary bladders of 499 wild raccoons from Luxembourg, Poland and five study sites in Germany. Pearsonema eggs were found in the urine sediment of 31 (6.2%) raccoons. Infested animals were found in all study areas with prevalence values ranging from 3.7% to 8.7%. No significant difference in prevalence was found either between animals in urban and rural areas or between sexes and age classes. Based on their morphology, the eggs were likely to be P. plica. Considering their increasing density in Central Europe, raccoons may play a previously overlooked role in environmental contamination with Personema eggs.

Ultraviolet/visible absorbance trends for beverages under simulated rinse conditions and development of data-driven prediction model

Water use during beverage production requires careful balancing of food safety, product quality, and environmental stewardship. Rinsing between flavor changes is one example where water can be used more efficiently. In this study, ultraviolet/visible (UV/Vis) absorbance properties of 20 beverages were characterized for undiluted product and diluted product (from 2 × to 5000 × dilution) to simulate rinsing. UV/Vis absorbance was a robust measurement and able to detect beverage components in rinse water. UV/Vis absorbance was also a sensitive measurement and able to detect most beverages at dilution levels of 1000 × or greater. UV/Vis absorbance was more sensitive than conductivity for most diluted products, and the sensitivity of UV/Vis absorbance was able to capture odor and taste thresholds for the beverages. A machine learning algorithm was used to develop a model to predict UV/Vis absorbance properties based on product ingredients and dilution. The results of this research suggest the possibility for in-line UV/Vis absorbance sensors to monitor and control rinsing and other processes during beverage production to optimize water use.

The Effectiveness of Torrefied Agricultural Wastes using Conventional Heating

The production of wastes volume from agricultural wastes have led to the selection as a renewable energy feedstock, and it has the opportunity into energy market. A comparison is made between two mode of wastes that is treated (rinse and soaking in water for 12 hours) and raw of coconut husk (CH) tap under torrefaction were investigated. This work has utilized of conventional heating method with mild oxygen concentration for the properties and combustion characteristics feedstock output. As such the influenced parameters with size of 750μm, holding temperature at (200, 240, and 280 °C), and residence duration at (20, 40 and 60 minutes) were involved within this torrefaction setup. The combustion behaviour of tested coconut husks marked three discrete zone, whereby the severity setup resulted to increase the fixed carbon (FC) value, thus leading to higher ignition temperature. The changes in mass yield and the increased of honeycomb-like and spongy-like porous structure were recorded for treated coconut husk than of the raw. The functional group results from Fourier Transform Infrared (FTIR) test showed a valuable interest of treated mode also been discussed.

Application of peracetic acid by spray or immersion in chicken carcasses to reduce cross‐contamination in the slaughter process

AbstractThe poultry industry uses several strategies during poultry processing to increase the safety and shelf life of fresh products. One possible intervention is the application of peracetic acid (PAA) on carcasses by spraying or immersion. This study aimed to evaluate the antimicrobial action of PAA and its capacity to prevent cross‐contamination when applied on chicken carcasses. First, the method of PAA application that achieved the greatest reduction against a Salmonella cocktail artificially inoculated into chicken carcasses and against naturally present microorganisms was determined. We used the maximum concentration allowed in the United States (0.02% PAA) determining that immersion method was more effective than spray. Next, the reduction of the same microorganisms was evaluated by immersing carcasses in 0.07% PAA. This concentration was defined in a previous study as the most effective post‐chiller without causing changes in quality. Finally, the reduction of cross‐contamination between 4 carcasses consecutively immersed in 0.07% PAA was investigated. The immersion in 0.07% PAA was able to reduce ~2.0 log CFU/ml of aerobic bacteria and Salmonella, and ~1.5 log CFU/ml of Enterobacteriaceae and Escherichia coli. The results of the cross‐contamination test suggest that rinse water containing 0.07% PAA could reduce contamination between carcasses and in the post‐chiller tank water. Therefore, 0.07% PAA showed potential to contribute to the safety and increased shelf life of chicken carcasses.

Fluoride Intake and Salivary Fluoride Retention after Using High-Fluoride Toothpaste Followed by Post-Brushing Water Rinsing and Conventional (1400-1450 ppm) Fluoride Toothpastes Used without Rinsing.

This study aimed to compare the fluoride intake and salivary fluoride levels after brushing with conventional (1400–1450 ppm) fluoride toothpaste containing different fluoride agents: amine fluoride (AmF), sodium fluoride (NaF), sodium monofluorophosphate (SMFP), potassium fluoride (KF), and a high-fluoride (5000 ppm) toothpaste containing NaF. Fourteen volunteers took part in the study. They were instructed to brush and spit without rinsing after using conventional toothpaste or brush and rinse with water after using a high-fluoride toothpaste. Fluoride concentrations were determined using ion-selective fluoride (09-37 type) in the saliva samples before and after procedures. Fluoride intake was estimated based on fluoride recovered after brushing. Additionally, the amount of fluoride present in the oral fluids and lost during the rapid clearance phase after toothbrushing was calculated based on salivary fluoride levels and saliva flow immediately after brushing. Salivary fluoride after using high-fluoride toothpaste was significantly higher than those observed after conventional products. Two hours after brushing, salivary fluoride concentrations did not differ significantly from baseline values (p > 0.05) unless a high-fluoride product was used. Results indicate that by refraining from rinsing after brushing with conventional toothpaste, we cannot obtain fluoride retention in saliva as with high-fluoride toothpaste. Fluoride ingestion was higher after using a high-fluoride product.

First Report of Botryosphaeria dothidea Causing Stem Canker and Dieback of Apple Trees in Ontario, Canada.

Apple trees (Malus domestica L. Borkh.) exhibiting extensive and unknown tree fruit decline symptoms were observed in commercial orchards over the past 5 years in Ontario, Canada. The trees exhibited shoot dieback, attached wilted leaves and cankers on the main trunk. Trees with rapid development of cankers upward from the graft union developed extensive vascular discoloration that resulted in sudden collapse of the entire tree. In 2018-19, up to 42% mortality was observed on 2- to 8-year old apple trees. Nine symptomatic trees were collected from two orchards located in southwestern and one in southcentral Ontario. Samples (1 cm length) were collected from symptomatic trunk and shoot tissue, surface sterilized with 70% ethanol for 30 sec, followed by 1% NaClO for 20 min and three rinses in sterile water. The samples were air-dried and placed on a 2% potato dextrose agar (PDA, Difco) culture media supplemented with kanamycin (50 mg L-1). The PDA plates were incubated at 22°C for 5 days in the dark. All fungal colony-forming units that developed were hyphal-tip transferred to individual PDA plates and incubated at 22°C for 7 days in the dark. Purified mycelial isolates were classified into morphotypes prior to molecular identification. One morphotype showed white to olive-green colonies that developed on a moderately dense mycelial mat with aerial hyphae. Several solitary and globose black pycnidia that contained a single ostiole were produced on pine needles on PDA after incubation at 22°C for 14 days in the dark. Conidia were hyaline, fusiform, aseptate with an average size of 3.9 - 5.2 x 21.4 - 26.6 μm (N=50). Genomic DNA was extracted from 5-day old culture of a representative isolate, #M68-17, grown on PDA using the Plant/Fungi DNA Isolation Kit (Norgen Biotech Corp., Thorold, ON, Canada). The rDNA internal transcribed spacer (ITS), translation elongation factor 1- alpha gene (TEF-1α), and β-tubulin gene (TUB2) were amplified using the primer pairs ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), and Bt2a/Bt2b (O'Donnell et al. 1998), respectively, and sequenced. The nucleotide sequences obtained (GenBank # MZ926850, MZ934654, MZ934655) were 100.00% similar to those of Botyrosphaeria dothidea (Moug. ex Fr.) Ces. & De Not. isolates from other hosts in several countries in the NCBI database (MT111097, MT309401, MN515421, respectively). Randomized Accelerated Maximum Likelihood (RAxML) analysis using the three gene sequence data was completed (Stamatakis et al. 2008). The isolate #M68-17 was clustered with high bootstrap support values with the B. dothidea isolates from the fungal biodiversity centre (CBS) collection, including the ex-epitype (CBS 115476, CBS 110302) (Fig. 1). A living culture of the representative isolate, #M68-17, was deposited in the Canadian Collection of Fungal Cultures (DAOMC 252246). Pathogenicity tests were conducted in the lab on wood cuttings and in planta. Ten 20 cm apple cuttings and five potted one year old apple seedlings were surface sterilized, wounded and inoculated with 4 mm mycelium agar plug from a 5-day old culture of isolate #M68-17 and wrapped with Parafilm. Three control apple cuttings and seedlings were inoculated with PDA plugs and incubated in the same environment. Cuttings were placed inside a clear plastic container with moist paper towels and incubated at room temperature in the dark. Seedlings were placed in an open-air area between two greenhouses and watered as needed. Twelve days post-inoculation, the average length of the developed necrotic lesions on cuttings was 8.8 ± 0.4 cm. Necrotic and sunken canker symptoms appeared at 10 days, spread upward from the inoculation point and by 6 weeks the upper portion of the seedling was dead (Fig. 2). B. dothidea was isolated from all the inoculated cuttings and seedlings, thus fulfilling Koch's postulates. Control cuttings and seedlings showed no symptoms, and the fungus was not isolated from the wood. B. dothidea was reported as a pathogen causing cankers on a wide range of woody crop plants including apples, almonds, pistachios, hazelnut, walnut, olive and grapes in the United States, China, Uruguay, Spain, Tunisia and Turkey (Chebil et al. 2014; Delgado-Cerrone et al. 2016; Moral et al. 2019; Tang et al. 2012; Türkölmez et al. 2016). However, this is the first report of B. dothidea causing stem canker and death of young apple seedlings in Ontario, Canada. The findings suggest that B. dothidea has the potential to severely affect apple production in Ontario. Accurate identification of pathogen(s) associated with apple decline will support management of the disease.

First report of bacterial leaf spot disease on Pueraria montana var. thomsonii caused by Robbsia andropogonis in China.

Pueraria montana var. thomsonii (Hereinafter referred to as Pmt) belongs to the Leguminosae and is widely distributed in China, Laos, Thailand, Myanmar, Bhutan and other Asian countries. The plant is called "Fenge" in China, and its root is widely used in medicine and food. In recent years, an unknown leaf spot disease of Pmt has occurred in Gaoming, Zhaoqing and Yunfu districts of Guangdong Province in China, where 1,600 hectares of Pmt plants were affected. The incidence rate of plants were more than 80% and led to 10-15% death of Pmt plants in Gaoming district. . In the early stage of the disease, radiating and water-soaking lesions appeared between the main veins and side veins of Pmt leaves. After the spread of the lesions, they formed brown and short strips with yellow haloes around them, which led to leaf shedding, plant death and decline of production. To isolate bacteria, diseased leaves were surface sterilized with 0.6% sodium hypochlorite solution for 30 s, followed by three consecutive rinses in distilled water. The leaves were aseptically macerated, and the macerate streaked on PDA medium. Whitish to dull white, mucoid, raised, round, and translucent colonies were obtained. All isolates were gram-negative and had a single, polar, sheathed flagellum. Sequences (approx. 1,458 bp each) of the 16S rRNA gene amplified from five isolates (FG2, FG3, FG9, FG12 and FG17) using primer pair 27F/1492R (Lane et al,1991) (GenBank Accession Nos. OL677034, OL677351, OL677352, OL677353 and OL677354 respectively) shared 99.93% sequence identity with that of Robbsia andropogonis (Synonyms: Burkholderia andropogonis) (Lopes-Santos et al,2017) type strain LMG2129 (NR104960.1). The specific 410-bp and 704-bp target fragments were also amplified from isolates using R. andropogonis-specific primers Pf/Pr (Bagsic et al,1995) and LJ23f/LJ24R (Duan et al,2009). The four housekeeping genes atpD, lepA, gyrB and rpoD were partially sequenced for FG9 isolates using primers atpD-F3/atpD-R3, lepA-F2/lepA-R, LJ23f/LJ24R and LJ25f/LJ26r (Duan et al,2009; Estrada-De et al,2013) respectively. Multilocus sequence analyses confirmed the isolates from Pmt as R. andropogonis. Physiological and biochemical tests revealed the isolates are negative for oxidase, arginine dihydrolase, saccharose and betaine, and positive for sorbitol, lactose and galactose (Gillis et al,1995; Lopes-Santos et al,2017). In addition, all isolates caused a hypersensitive reaction on leaves of Nicotiana benthamiana and were pathogenic to some crops, including maize (Zea mays), sorghum (Sorghum bicolor), carnation (Dianthus caryophilus), common bean (Phaseolus vulgaris), tomato. Five isolates (FG2, FG3, FG9, FG12 and FG17) pathogenicity were tested twice with a total of three replications per isolate. Two young leaves each of 3-month-old Pmt plants grow in greenhouse were sprayed a bacterial suspension at 108 CFU/ml, then covered the inoculated leaves individually with plastic bags for 24 h, and incubated at 100% relative humidity with 16 h of daylight at 30°C and 8 h of darkness at 22°C in a greenhouse. Radiating and water-soaked lesions with yellow haloes were observed between the main veins and side veins of Pmt leaves 5 days after inoculation and were similar to those caused by R. andropogonis in the field. Koch's postulates were fulfilled by reisolating bacteria from typical lesions on inoculated plants. And the reisolated bacteria were identical to the inoculated ones. To our knowledge, this is the first report of R. andropogonis on Pueraria montana var. thomsonii in China.

Assessing the potential use of composite titanium-containing coagulants, when treating wastewater from copper compounds

Wastewater treatment from heavy metals is a complicated and currently relevant task. Electrochemical coating processes are undoubtedly a main source of heavy metal compounds in wastewater. The second major source of heavy metal input to the environment is mining and processing of various ores. As part of the conducted research, the author assessed a potential intensification of wastewater treatment from copper compounds, using conventional and titanium-containing chemical agents. The samples taken for research were wastewater from electroplating facilities, containing copper compounds, rinse waters after neutralization and sedimentation, and mine waters. It is found that the use of pure titanium salts (titanyl sulfate) contributes to achieving the minimum residual concentration of copper compounds for all the wastewater samples under study; however, their extremely high cost makes this process economically impractical. Composite titanium-containing chemical agents produced by modification of aluminum sulfate with added titanium compounds significantly increased efficiency of the base chemical agent and reduced the residual concentration of copper in wastewater by almost 30%. Iron-containing coagulant was not efficient for the task. Factoring into a minimum amount of added titanium compounds (5–10 % wt.), the cost of composite titanium-containing chemical agents is slightly higher than the cost of pure aluminum sulfate, while the lower residual concentration of copper will significantly reduce the amount of penalties from the regulatory authorities for discharging pollutants into the city drainage main above the limit. It is stated that composite titanium-containing coagulants also contribute to a significant increase in efficiency of removing suspended particles and the coagulation sludge sedimentation rate, entailing reduced sizes of wastewater treatment facilities or their increased performance.The author gratefully acknowledges Natalia E. Kruchinina, research advisor, Doctor of Engineering Sciences, Professor, Head of the Industrial Ecology Department.The measurements were made using equipment of the Mendeleev Research Equipment Sharing Center.

Potential risk of SARS-CoV-2 infection among people handling linens used by COVID-19 patients before and after washing

The risk of SARS-CoV-2 infection when people handle linens is uncertain. We examined the presence of SARS-CoV-2 on linens, in the air, and on personal protective equipment (PPE) to assess potential infection risk among individuals who handle linens used by SARS-CoV-2-infected people. Patients in a hospital and an accommodation facility who tested positive for SARS-CoV-2 participated in this study in 2020. Linen samples before washing or disinfection, rinse water after washing or disinfection, air in the workplace at the hospital and an accommodation facility, and the PPE worn by linen-handling people were tested for SARS-CoV-2 RNA and viable viruses. Among 700 samples from 13 SARS-CoV-2-infected participants and their surrounding environment, SARS-CoV-2 RNA was detected from 14% (52/362) of the linens used by COVID-19 patients (cycle threshold [Ct] value: 33–40). SARS-CoV-2 RNA was detected from 8% (2/26) of rinse water after washing or disinfection, from 15% (16/104) of air samples in the workspace, and from 10% (5/52) of gowns worn by linen-handling people, all with high Ct values (> 36). No SARS-CoV-2 was isolated from any samples. The potential risk of SARS-CoV-2 infection from handling linens used by SARS-CoV-2-infected people exists but appears to below.

A Reverse Osmosis Process to Recover and Recycle Trivalent Chromium from Electroplating Wastewater.

Electroplating generates high volumes of rinse water that is contaminated with heavy metals. This study presents an approach for direct metal recovery and recycling from simulated rinse water, made up of an electroplating electrolyte used in industry, using reverse osmosis (RO). To simulate the real industrial application, the process was examined at various permeate fluxes, ranging from 3.75 to 30 L·m−2·h−1 and hydraulic pressures up to 80 bar. Although permeance decreased significantly with increasing water recovery, rejections of up to 93.8% for boric acid, >99.9% for chromium and 99.6% for sulfate were observed. The final RO retentate contained 8.40 g/L chromium and was directly used in Hull cell electroplating tests. It was possible to deposit cold-hued chromium layers under a wide range of relevant current densities, demonstrating the reusability of the concentrate of the rinsing water obtained by RO.

Cr(VI) adsorption by Lemna minor considering operational, chemical and biological factors

The conditions for Cr(VI) adsorption by Lemna minor (LM) were analyzed. Regarding the macrophite the parameters were: growth rate and calcination temperature. Adsorption capacity of LM was measured as a function of the Cr(VI) concentration, stirring contact time, stirring speed, temperature, and pH; as well as considering the quantity of LM units and the LM root length. The data were well adjusted to the kinetic pseudo second order model and to the Langmuir isotherm model. Acid pH enhanced the adsorption because of the negative charge Cr (VI) and the protonated surface of the adsorbent material. Experiments by using a rinse water from the chromium plating process showed that cromium was successfully removed by LM. The best conditions were found for the adsorption process of Cr(VI) by LM.