According to existing literature, there are no conclusive results on the impact of stirring on hydrothermal carbonization (HTC); some studies report a significant impact on the product's properties, while others indicate no influence. This study investigates the influence of stirring rate on several responses and properties of HTC products, including solid mass yield, solid carbon fraction, surface area, surface functional groups, morphology, and the fate of inorganic elements during HTC. Waste biomass was introduced as a feedstock to a 2 L HTC reactor, where the effects of temperature (180-250 °C), residence time (4-12 h), biomass to water (B/W) ratio (1-10%), and stirring rate (0-130 rpm) were investigated.
View Article and Find Full Text PDFThis study aimed to calibrate and validate the MFI-UF method in order to ensure the accuracy of particulate fouling measurements in RO. Firstly, the MFI-UF calibration was examined using two solutions of standard particles (dextran and polystyrene). Two main criteria were investigated: (i) MFI-UF linearity with particle concentrations at both low and high ranges of fouling potential and (ii) the reproducibility of MFI-UF linearity.
View Article and Find Full Text PDFMedicinal plants belonging to the Verbenaceae family demonstrated antidepressant effects in preclinical studies. Depression is one of the largest contributors to the global health burden of all countries. Plants from the Aloysia genus are traditionally used for affective disorders, and some of them have proven anxiolytic and antidepressant activity.
View Article and Find Full Text PDFRapid population growth and urbanization are two main drivers for the over-abstraction of conventional freshwater resources in various parts of the world, which leads to the situation of water scarcity (per capita availability <1000 m3/year). Predictions based on the World Bank projected population data and the FAO AQUASTAT database for freshwater availability show that by 2050, 2 billion people living in 44 countries will likely suffer from water scarcity, of which 95% may live in developing countries. Among these, the countries that will likely be most strongly hit by water scarcity by 2050 are Uganda, Burundi, Nigeria, Somalia, Malawi, Eritrea, Ethiopia, Haiti, Tanzania, Niger, Zimbabwe, Afghanistan, Sudan, and Pakistan.
View Article and Find Full Text PDFObjectives: The purpose of this study was to evaluate the grade distribution of screen-detected ductal carcinoma in situ (DCIS) diagnosed in Ireland, in the context of the clinical trials currently underway to determine if active surveillance is a feasible management option for low-risk DCIS.
Setting: BreastCheck is the national breast screening programme in Ireland, offering screening to women aged 50 to 69 every two years.
Methods: This study was a secondary analysis of data collected by BreastCheck on all screen-detected DCIS diagnosed in the 12 years of nationwide screening.
Membranes (Basel)
March 2022
The objectives of this study are to assess the performance of antiscalants in increasing the recovery (≥85%) of a reverse osmosis (RO) plant treating anaerobic groundwater (GW) in Kamerik (the Netherlands), and to identify scalants/foulant that may limit RO recovery. Five different commercially available antiscalants were compared on the basis of their manufacturer-recommended dose. Their ability to increase the recovery from 80% to a target of 85% was evaluated in pilot-scale measurements with anaerobic GW and in once-through lab-scale RO tests with synthetic (artificial) feedwater.
View Article and Find Full Text PDFWater Res
September 2021
The bacterial growth potential (BGP) of drinking water is widely assessed either by flow cytometric intact cell count (BGP) or adenosine triphosphate (BGP) based methods. Combining BGP and BGP measurements has been previously applied for various types of drinking water having high to low growth potential. However, this has not been applied for water with ultra-low nutrient content, such as remineralised RO permeate.
View Article and Find Full Text PDFIn this study, the removal of particulate, organic and biological fouling potential was investigated in the two-stage dual media filtration (DMF) pretreatment of a full-scale seawater reverse osmosis (SWRO) desalination plant. Moreover, the removal of fouling potential in two-stage DMF (DMF pretreatment) was compared with the removal in two-stage DMF installed after dissolved air floatation (DAF) (DAF-DMF pretreatment). For this purpose, the silt density index (SDI), modified fouling index (MFI), bacterial growth potential (BGP), organic fractions and microbial adenosine triphosphate (ATP) were monitored in the pretreatment processes of two full-scale SWRO plants.
View Article and Find Full Text PDFMeasuring the bacterial growth potential of seawater reverse osmosis (SWRO) feed water is an issue that is receiving growing attention. This study developed and demonstrated the applicability of the flow-cytometry (FCM)-based bacterial growth potential (BGP) method to assess the biofouling potential in SWRO systems using natural microbial consortium. This method is relatively fast (2-3 days) compared to conventional bioassays.
View Article and Find Full Text PDFSeveral potential growth methods have been developed to monitor biological/organic fouling potential in seawater reverse osmosis (SWRO), but to date the correlation between these methods and biofouling of SWRO has not been demonstrated. In this research, the relation between a new adenosine triphosphate (ATP)-based bacterial growth potential (BGP) test of SWRO feed water and SWRO membrane performance is investigated. For this purpose, the pre-treatment of a full-scale SWRO plant including dissolved air flotation (DAF) and two stage dual media filtration (DMF) was monitored for 5 months using BGP, orthophosphate, organic fractions by liquid chromatography coupled with organic carbon detection (LC-OCD), silt density index (SDI), and modified fouling index (MFI).
View Article and Find Full Text PDFAlthough water produced by reverse osmosis (RO) filtration has low bacterial growth potential (BGP), post-treatment of RO permeate, which is necessary prior to distribution and human consumption, needs to be examined because of the potential re-introduction of nutrients/contaminants. In this study, drinking water produced from anaerobic groundwater by RO and post-treatment (ion exchange, calcite contactors, and aeration) was compared with that produced by conventional treatment comprising (dry) sand filtration, pellet softening, rapid sand filtration, activated carbon filtration, and UV disinfection. The multi-parametric assessment of biological stability included bacterial quantification, nutrient concentration and composition as well as bacterial community composition and diversity.
View Article and Find Full Text PDFMeasuring bacterial growth potential (BGP) involves sample pre-treatment and inoculation, both of which may introduce contaminants in ultra-low nutrient water (e.g., remineralized RO permeate).
View Article and Find Full Text PDFSeveral software tools are available that can assess the performance of nonrevenue water (NRW) in water distribution networks and plan for reduction measures. Of the 21 tools that have been reported in the literature, 12 are freely available. The creation of these many tools and different versions of each individual tool indicates the promising future of NRW software development.
View Article and Find Full Text PDFBank filtration (BF) has been used for many years as an economical technique for providing high-quality drinking water. However, under anaerobic conditions, the aquifer release of undesirable metal(loid)s, such as iron manganese, and arsenic, reduces the bank filtrate quality and thus restricts the application of this technique. This study investigates the impact of the organic-matter composition of source water on the mobilisation of Fe, Mn, and As during the anaerobic BF process.
View Article and Find Full Text PDFThe feasibility of wellhead water treatment in small communities for nitrate removal and salinity reduction via a flexible high recovery RO system was evaluated through analysis of treatment options, laboratory and onsite field tests. In small remote communities that rely on septic systems for residential wastewater treatment, discharge of the RO residual stream (containing nitrate) to the community septic tank is shown to be a feasible option. It is demonstrated that RO treatment with a system that employs partial concentrate recycle, integrated with a pressure intensifier, enabled the use of a relatively low-pressure feed pump while allowing high recovery operation.
View Article and Find Full Text PDFAims: To investigate medical students' perspectives on the influence of their undergraduate course and the UK prescribing safety assessment (PSA) on the acquisition of practical prescribing skills.
Methods: An online questionnaire comprising multiple choice and open-ended questions was available to UK medical students in years 3, 4 and 5. Descriptive statistics and thematic analysis were completed.
Alternative disinfection technologies may overcome some of the limitations of conventional treatment applied in swimming pools: chlorine-resistant pathogens (e.g. Cryptosporidium oocysts and Giardia cysts) and the formation of chlorinated disinfection byproducts.
View Article and Find Full Text PDFEnsuring the biological stability of drinking water is essential for modern drinking water supply. To understand and manage the biological stability, it is critical that the bacterial growth in drinking water can be measured. Nowadays, advance treatment technologies, such as reverse osmosis (RO), are increasingly applied in drinking water purification where the produced water is characterized by low levels of nutrients and cell counts.
View Article and Find Full Text PDFThe density of fungal contamination and the fungal diversity in an indoor swimming pool facility were assessed. A total of 16 surface samples and 6 water samples were analysed by using a combination of different (semi-) selective culture media. Isolated fungal colonies were identified to the genus or species level by sequencing of the internal transcribed spacer (ITS).
View Article and Find Full Text PDFBackground: The aim of this study was to determine the training provisions in practical safe prescribing for foundation doctors in NHS hospitals located in the South Thames region.
Methods: A web-based questionnaire was distributed by e-mail to all 1762 foundation doctors in the South Thames Foundation School (STFS) region. In addition, a separate questionnaire was distributed to prescribing training Leads at 15 NHS Hospital Trusts.
The occurrence of 32 pharmaceuticals and 14 UV filters in swimming pools and spas was studied. Fifty-one water samples were collected from 17 pools located in sport centres and hotels in Catalonia, Spain. The samples were analysed by liquid chromatography-tandem mass spectrometry.
View Article and Find Full Text PDFTransparent exopolymer particles (TEP) and their precursors produced by phyto-/bacterio-planktons in fresh and marine aquatic environments are increasingly considered as a major contributor to organic/particulate and biological fouling in micro-/ultra-filtration and reverse osmosis membrane (RO) systems. However, currently established methods which are based on Alcian blue (AB) staining and spectrophotometric techniques do not measure TEP-precursors and have the tendency to overestimate concentration in brackish/saline water samples due to interference of salinity on AB staining. Here we propose a new semi-quantitative method which allows measurement of both TEP and their colloidal precursors without the interference of salinity.
View Article and Find Full Text PDFThe efficiency of manganese removal in conventional groundwater treatment consisting of aeration followed by rapid sand filtration, strongly depends on the ability of filter media to promote auto-catalytic adsorption of dissolved manganese and its subsequent oxidation. Earlier studies have shown that the compound responsible for the auto-catalytic activity in ripened filters is a manganese oxide called Birnessite. The aim of this study was to determine if the ripening of manganese removal filters and the formation of Birnessite on virgin sand is initiated biologically or physico-chemically.
View Article and Find Full Text PDF