Pesticides, personal care products, industrial chemicals often pollute surface-and groundwater sources. With trace concentrations and low molecular weights, these micropollutants (MPs) easily penetrate through treatment systems and impose a real health threat on drinking water consumers. The absence of a dedicated MP-retaining treatment technology at water treatment plants results in a constant consumption of MP-contaminated water. Advanced oxidation processes, and in particular the Fenton reaction, can successfully degrade MPs if other, larger, fractions of organics are retained. Here, we suggest a novel combined two-stage retention-degradation approach. Ceramic membranes retain large organics such as bovine serum albumin (BSA). Fenton processes disintegrate nonretained MPs such as methylene blue (MB) and bisphenol A (BPA) that penetrate through the membrane. The efficiency of the suggested approach is high. Single-layered ultrafiltration membrane retains more than 96% BSA and degrades 40-50% of MB and BPA. The degree of degradation depends on both the impregnated metal oxide and the concentration of hydrogen peroxide. Vanadium-based catalysts retain more than 90% MPs but leach into permeate. Ferric oxides were the only stable catalysts that performed better in membranes than when impregnated on α-Al 2 O 3 pellets. A combined retention-degradation can be optimized to result in superior degree of retention. Catalytic ceramic membranes can retain large organic molecules and decompose MPs simultaneously. Three parameters affect the process efficiency: the dynamics of the influent fluid, the catalyst dose and the contact time.
Many small drinking water treatment systems disinfect using only ultraviolet light, which provides minimal adenovirus inactivation at common doses. There is uncertainty in jurisdictions around the world about whether such practices should be accepted by regulators, or whether there is a need to specify a treatment target for adenovirus. A preliminary objective of this study was to determine whether adequate adenovirus information exists to conduct a meaningful quantitative microbial risk assessment (QMRA). The study then applied the QMRA framework to draw conclusions about whether there is justification to regulate adenovirus, and to identify weaknesses in those conclusions. A thorough review revealed that the quality of data available to conduct the analysis was poor. Using the (limited) data available, the QMRA suggests that adenovirus may pose risks similar to other viruses that are regulated.A lack of information about the concentration of adenovirus in source waters makes it difficult to propose a compelling evidence-based argument either for or against the need to require adenovirus treatment.Furthermore, management of risk from waterborne adenovirus should take into account an endemic rate of infection from non-waterborne exposures that appears to obscure accepted levels of waterborne risk.
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