Inanimate Surfaces as a Source of Hospital Infections Caused by Fungi, Bacteria and Viruses with Particular Emphasis on SARS-CoV-2.

The carriers of nosocomial infections are the hands of medical personnel and inanimate surfaces. Both hands and surfaces may be contaminated as a result of contact with the patient, their body fluids, and touching contaminated surfaces in the patient's surroundings. Visually clean inanimate surfaces are an important source of pathogens. Microorganisms have properties thanks to which they can survive in unfavorable conditions, from a few days to several months. Bacteria, viruses and fungi are able to transmit from inanimate surfaces to the skin of the patient and the medical staff. These pathogens include SARS-CoV-2, which can survive on various types of inanimate surfaces, being a potential source of infection. By following the recommendations related to washing and disinfecting hands and surfaces, and using appropriate washing and disinfecting agents with a broad biocidal spectrum, high material compatibility and the shortest duration of action, we contribute to breaking the chain of nosocomial infections.

Biosorption of LMW PAHs on activated sludge aerobic granules under varying BOD loading rate conditions.

Polycyclic aromatic hydrocarbons belong to the main priority substances for the aquatic environment. One of the emission sources of these compounds to environment is wastewater discharged from conventional wastewater treatment systems, which are not designed to cope with this type of pollution. Thus, due to the widely discussed properties of aerobic granular activated sludge in the literature - a conducted study has proven its ability to remove LMW PAHs (naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flu), phenanthrene (Phe) and anthracene (Ant)) from wastewater by biosorption process at varying loadings of organic compounds expressed as BOD (kg/kg·d) on the activated sludge mass. The maximum biosorption of Nap was 605 µg/kgd.m., Acy equals to 134 µg/kgd.m., Ace equals to 355 µg/kgd.m. Flu equals to 104 µg/kgd.m. Phe equal to 204 µg/kgd.m. and Ant equal to 173 µg/kgd.m. The study showed that the BOD loading rate is one of the factors affecting the biosorption process of LMW PAHs. However, as the amount of adsorbed LMW PAHs increased, the condition of aerobic granular activated sludge deteriorated, which was evidenced by gradual increase in the values of technological parameters of activated sludge (SVI, HRT, SRT) and a smaller increase in activated sludge dry mass.

Mineral Materials Coated with and Consisting of MnOx-Characteristics and Application of Filter Media for Groundwater Treatment: A Review.

For groundwater treatment, the technologies involving oxidation on MnOx filter bed are beneficial, common, and effectively used. The presence of MnOx is the mutual feature of filter media, both MnOx-coated mineral materials like quartz sand and gravel, chalcedonite, diatomite, glauconite, zeolite, or anthracite along with consisting of MnOx manganese ores. This review is based on the analysis of research and review papers, commercial data sheets, and standards. The paper aimed to provide new suggestions and useful information for further investigation of MnOx filter media for groundwater treatment. The presented compilations are based on the characteristics of coatings, methods, and conditions of its obtaining and type of filter media. The relationship between the properties of MnOx amendments and the obtained purification effects as well as the commonly used commercial products, their features, and applications have been discussed. The paper concludes by mentioning about improving catalytic/adsorption properties of non-reactive siliceous media opposed to ion-exchange minerals and about possible significance of birnessite type manganese oxide for water treatment. Research needs related to the assessment of the use MnOx filter media to heavy metals removal from groundwater in field operations and to standardize methodology of testing MnOx filter media for water treatment were identified.

Influence of Integrated Membrane Treatment on the Phytotoxicity of Wastewater from the Coke Industry.

In this paper, coke wastewater that had passed through biological and integrated membrane processes (filtration on sand bed-reverse osmosis) was chosen to assess the phytotoxicity of selected industrial wastewater with regard to the test plant-Vicia faba. An innovative research technique in vitro test was conducted in a large scale phytothrone chamber on two matrices: cotton and Murashige and Skoog Basal Medium (MSBM). The toxicity of wastewater was evaluated for samples: (1) treated in the treatment plant by biological processes, (2) filtrated through a sand bed and filtrated (3) reverse osmosis (RO) membrane. The results showed that there is a noticeable correlation between increasing concentrations of wastewater and seed germination of the test plant. Although the wastewater collected from the coke plant was treated biologically, it showed very high levels of germination inhibition (90-98% for cotton matrix and 92-100% for MSBM matrix) and strong toxic effects. The wastewater collected from the coke plant showed a significantly greater phytotoxic effect compared with those obtained from the effluent treated on a sand bed and in RO. However, wastewater, even after treatment on a sand bed (reduction of COD-39%, TN-46%, TOC-42%, TC-47%, SS-50%, 16PAHs-53%), was still toxic and germination inhibition was in the range of 24-48% for the cotton matrix and 14-54% for the MSBM matrix. The toxicity of wastewater treated in the membrane process was the lowest (reduction of COD-85%, TN-95%, TOC-85%, TC-86%, SS-98%, 16PAHs-67%). The germination inhibition was in the range of 4-10% for the cotton matrix and 2-12% for the MSBM matrix. These samples are classified as non-toxic or slightly toxic to the model plant. The present study highlights the necessity of monitoring not only the basic physical and chemical indicators (including the level of toxic substances as PAHs), but also their effect on the test organisms in wastewater samples.

The effect of selected acidic or alkaline chemical agents amendment on leachability of selected heavy metals from sewage sludge.

The aim of the study was to evaluate the effect of acidic (Fenton's reagent, peracetic acid) or alkaline (CaO) chemical agents amendment on chemical forms of Pb, Ni, and Cd in sewage sludge. The dose of Fenton's reagent was as follows: Fe2+=1g·L-1, Fe2+/H2O2=1:100; stabilisation lasted for 2h. The dose of CaO was equal to 1g CaO·gd.m.-1. The dose of CH3COOOH was 2.5g·L-1. Total concentration of all metals in the digested sewage sludge was higher than in the soil and it did not meet Polish law requirements. Acidic chemical stabilisation of sludge did not significantly decrease total metal content in the sludge. Amendment of CaO decreased the content of Pb, Cd, and Ni in the sludge. Chemical fractions of heavy metals were identified in the sludge (exchangeable, carbonate bound, iron oxides bound, organic and residual). The results indicate that stabilisation of the sludge with Fenton's reagent and peracetic acid increased the exchangeable fraction of Pb, Cd, and Ni compared to the digested sludge, but it did not increase shares of mobile forms of metals considered as a total of I-st and II-nd fraction. Amendment of CaO increased percent share of examined metals in residual fraction. Not-mobile fractions of examined metals overweight the mobile ones in all sludge samples regardless of the treatment method.

Application of UV-rays in removal of polycyclic aromatic hydrocarbons from treated wastewater.

This study was undertaken to investigate the removal of PAHs by UV-rays from treated wastewater. Samples of wastewater originating from a municipal treatment plant were taken twofold (series I and series II). The initial concentration of PAHs ranged: 0.8 µg/L (in series I) and 1.2 µg/L (in series II), respectively. A standard mixture of 16 compounds was added to the wastewater samples. The amount of individual hydrocarbons in the added mixture was equal to 40 µg/L, (in series I) and 50 µg/L, (in series II), respectively. The samples of wastewater without the added standard mixture were treated as a control samples. All samples of wastewater were exposed to UV-rays during 10, 20, 30 and 60 seconds, respectively. Afterwards, the PAHs concentration in both the wastewater samples containing the standard mixture and in the control samples was determined. Determinations of PAHs concentration in wastewater samples in each series were made in triplicates. A quantitative analysis of PAHs was provided by gas chromatography-mass spectrometry (GC-MS). It was found that exposition to ultraviolet rays resulted in the decrease in the concentration of PAHs in the wastewater samples without added standard mixture up to 65%. The efficiency of the removal of hydrocarbons grouped according to a number of rings was in the range of 0 (for 5- ring and 6-ring of PAHs) to 71% (for naphthalene). It was also found that exposure of wastewater samples to UV-rays resulted in a decrease of PAHs concentration in wastewater samples with the added standard mixture up to 84%. The efficiency of the removal of hydrocarbons grouped according to a number of rings differed significantly (to 94% for naphthalene).

PAHs balance in solid and liquid phase of sewage sludge during fermentation process.

The results of the quantitative and qualitative analysis of PAHs both in sewage sludge and in supernatants before, during, and after methane fermentation process are presented in this paper. The investigations were carried out under laboratory scale in two series. The sludge samples originated from a municipal treatment plant. The process of fermentation was conducted using batch tests (a one-off batch supplemented with sludges). The content of 16 PAHs, listed by the US EPA, was determined using GC-MS technique. The aim of this investigation was to study changes in contribution groups of hydrocarbons (2-, 3-, 4-, 5-, and 6-ring) in relation to total concentration in PAHs. The objective of these investigations was to follow the changes in the PAHs content not only in sewage sludge (drymass) but also in supernatants (in the liquid phase), and to follow changes in concentration of PAHs during the methane fermentation process as well. The balance of PAHs load in sewage sludge and supernatants mixture was also calculated. An approximate two-fold decrease in dry matter of sludge was observed during the methane fermentation process. During sewage sludge digestion process 3- and 4-ring compounds were released from a solid phase to supernatants.