Application of suspended ion exchange, in-line coagulation and ceramic membranes for surface water treatment

A long term, large scale pilot study was performed to assess the use of a novel process based on suspended ion exchange (SIX®) and in-line coagulation (ILCA®) pretreatment for ceramic membrane filtration (CeraMac®), for treating three variable quality UK surface waters. SIX was shown to remove similar quantities of dissolved organic carbon (DOC) to coagulation for low to moderate DOC source waters. However, during periods of high DOC concentrations and high specific UV absorbance, the removal of organic compounds was reduced. The long term DOC removal data for the SIX process indicated good performance, which was in line with previously reported results from studies using other suspended ion exchange processes. Organic characterisation using liquid chromatography–organic carbon detection (LC-OCD) revealed the differing selectivities of the SIX and ILCA processes, for low and high molecular weight organic fractions respectively. When these processes were used in combination, a broad range of organic compounds were removed, leading to a 50% reduction in DOC concentration in comparison with an existing full scale conventional treatment process. Subsequently, disinfection by-product (DBP) formation was significantly reduced (62% vs. the conventional process) due to the lower DOC concentration, reduced specific reactivity of the residual organic compounds and reduced formation of brominated DBPs. Removal of high molecular weight organic compounds (biopolymers) was shown to be critical for stable operation of ceramic membranes at high flux. Optimised in-line coagulation (ILCA) pretreatment (which flocculated the biopolymers) led to negligible membrane adsorption of organic compounds, as low molecular weight (LMW) fractions (which are recalcitrant to coagulation) were shown not to be retained by the membrane. Due to this, when using optimised ILCA, additional removal of LMW organic fractions by using SIX in combination with ILCA provided no measureable benefit with regards to membrane fouling suppression. Automation of coagulant dosing was achieved for the high SUVA waters tested, using simple feed forward control based on the UV transmittance of the feed water. The application of this automated system led to very low membrane fouling rates (0.24kPa/day), despite highly challenging operating conditions of elevated fluxes (185 L m- 2 h- 1 ) and highly variable feed water dissolved organic carbon concentrations (1-10mg/l)

Gaining insights from Candida biofilm heterogeneity: one size does not fit all

Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us

Communal land reform in Zambia: governance, livelihood and conservation

Magister Philosophiae (Land and Agrarian Studies) - MPhil(LAS)Communal land tenure reform in Zambia is the overarching subject of study in this thesis. It is an important issue across southern Africa, raising questions of governance, livelihood security and conservation. WIldlife is a 'fugitive' and 'mobile' resource that traverses the spatially fixed tenure of communal lands, national parks and public forest reserves. The management of wildlife therefore requires that spatially defined proprietorial rights accommodate wildlife's temporal forage use. Land may bebounded in tenure, but if bounded by fences its utility as wildlife habitat is undermined. If land is unfenced, but its landholder cannot use wildlife then it is more a liability than an asset. Africa's terrestrial wildlife has enormous biodiversity value but its mobility requires management collaboration throughout its range, and the resolution of conflicting ecological and economic management scales. The paper does not aim to describe and explain the internal communal system of tenure over land and natural resources but rather how the communal system interacts with the state and the private sector.South Afric