Browsing by Author "Goslan, Emma Harriet"
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Item Open Access Application of ultraviolet light-emitting diodes (UV-LED) to full-scale drinking-water disinfection(MDPI, 2019-09-11) Jarvis, Peter; Autin, Olivier; Goslan, Emma Harriet; Hassard, FrancisUltraviolet light-emitting diodes (UV-LEDs) have recently emerged as a viable technology for water disinfection. However, the performance of the technology in full-scale drinking-water treatment systems remains poorly characterised. Furthermore, current UV disinfection standards and protocols have been developed specifically for conventional mercury UV systems and so do not necessarily provide an accurate indication of UV-LED disinfection performance. Hence, this study aimed to test the hypothesis that a full-scale UV-LED reactor can match the Cryptosporidium inactivation efficiency of conventional mercury UV reactors. Male-specific bacteriophage (MS2) was used as the Cryptosporidium spp. surrogate microorganism. The time-based inactivation efficiency of the full-scale reactor was firstly compared to that of a bench-scale (batch-type) UV-LED reactor. This was then related to mercury UV reactors by comparing the fluence-based efficiency of the bench-scale reactor to the USEPA 90% prediction interval range of expected MS2 inactivation using mercury UV lamps. The results showed that the full-scale UV-LED reactor was at least as effective as conventional mercury UV reactors at the water-quality and drive-current conditions considered. Nevertheless, comparisons between the bench- and full-scale UV-LED reactors indicated that improvements in the hydraulic flow profile and power output of the full-scale reactor could help to further improve the efficiency of UV-LED reactors for municipal drinking water disinfection. This represents the world’s first full-scale UV-LED reactor that can be applied at municipal water treatment works for disinfection of pathogenic microorganisms from drinking water.Item Open Access Carbonaceous and nitrogenous disinfection by-product formation from algal organic matter(Elsevier, 2016-12-10) Goslan, Emma Harriet; Seigle, Céline; Purcell, Diane; Henderson, Rita Kay; Parsons, Simon A.; Jefferson, Bruce; Judd, Simon J.Seasonal algal blooms in drinking water sources release intracellular and extracellular algal organic matter (AOM) in significant concentrations into the water. This organic matter provides precursors for disinfection by-products (DBPs) formed when the water is subsequently chlorinated at the final disinfection stage of the potable water treatment process. This paper presents results of AOM characterisation from five algal species (three cyanobacteria, one diatom and one green) alongside the measurement of the DBP formation potential from the AOM of six algal species (an additional diatom). The character was explored in terms of hydrophilicity, charge and protein and carbohydrate content. 18 DBPs were measured following chlorination of the AOM samples: the four trihalomethanes (THMs), nine haloacetic acids (HAAs), four haloacetonitriles (HANs) and one halonitromethane (HNM). The AOM was found to be mainly hydrophilic (52 and 81%) in nature. Yields of up to 92.4 μg mg−1 C carbonaceous DBPs were measured, with few consistent trends between DBP formation propensity and either the specific ultraviolet absorbance (SUVA) or the chemical characteristics. The AOM from diatomaceous algae formed significant amounts of nitrogenous DBPs (up to 1.7 μg mg−1 C). The weak trends in DBPFP may be attributable to the hydrophilic nature of AOM, which also makes it more challenging to remove by conventional water treatment processes.Item Open Access Effect of elevated UV dose and alkalinity on metaldehyde removal and THM formation with UV/TiO2 and UV/H2O2(Elsevier, 2015-11-26) Jefferson, Bruce; Jarvis, Peter; Bhagianathan, Govind Kannoly; Smith, Heather M.; Autin, Olivier; Goslan, Emma Harriet; MacAdam, Jitka; Carra, IreneDrinking water production needs to increasingly consider removal of background organic matter and trace micropollutants without increasing disinfection-by-product (DBP) formation potential. The presented data demonstrates the efficacy of both UV/H2O2 and UV/TiO2 in removing the pesticide metaldehyde to below drinking water compliance levels in both real and synthetic waters. This pesticide has proven to be unaffected by conventional water treatment processes such as granular activated carbon and is responsible for many of the water company compliance failures in the UK. The potential of UV/H2O2 is further demonstrated to offer an alternative approach for the removal of recalcitrant organic matter to ensure DBP compliance as long as extended UV doses of over 10,000 mJ cm−2 are applied at the optimum peroxide dose of 8 mM. Alkalinity and UV dose have an impact on DBP formation: at low UV fluences, increased alkalinity reduced the DBP formation. The UV/TiO2 process was observed to be inhibited in the presence of alkalinity. Aggregation studies and comparison of the catalyst fractal dimension showed that the process inhibition is mainly due to aggregation. This restricts the surface area available for reactions, rather than changes in the catalyst properties or carbonate radical scavenging, which is often the reasoning attributed to photocatalysis inhibition. Hence, the presented results indicate that decreasing the catalyst aggregation is the key to apply photocatalysis as drinking water treatment.Item Open Access A model for predicting dissolved organic carbon distribution in a reservoir water using fluorescence spectroscopy(Elsevier Science B.V., Amsterdam., 2004-02-01T00:00:00Z) Goslan, Emma Harriet; Voros, Sandrine; Banks, Jenny; Wilson, Derek; Hillis, Peter; Campbell, Andrew T.; Parsons, Simon A.A number of water treatment works (WTW) in the north of England (UK) have experienced problems in reducing the dissolved organic carbon (DOC) present in the water to a sufficiently low level. The problems are experienced in autumn/ winter when the colour increases and the coagulant dose at the WTW needs to be increased in order to achieve sufficient colour removal. However, the DOC content of the water varies little throughout the year. To investigate this further, the water was fractionated using resin adsorption techniques into its hydrophobic (fulvic and humic acid fractions) and hydrophilic (acid and non-acid fractions) components. The fractionation process yields useful information on the changing concentration of each fraction but is time consuming and labour intensive. Here, a method of rapidly determining fraction concentration was developed using fluorescence spectroscopy. The model created used synchronous spectra of fractionated material compared against bulk water spectra and predicted the fraction concentrations to within 10% for a specific water. The model was unable to predict fraction concentrations for waters from a different watershed.Item Open Access Natural organic matter - The relationship between character and treatability(Iwa Publishing, 2004-12-31T00:00:00Z) Parsons, Simon A.; Jefferson, Bruce; Goslan, Emma Harriet; Jarvis, Peter; Fearing, David AndrewThe characterisation and treatment of natural organic matter are becoming more important to the water utilities in the UK and around the world. This paper looks at the relationship between bulk and fractionated organic material and the performance of conventional water treatment processes.