Search

Small public water supplies that use surface water as a source for drinking water are frequently faced with elevated levels of color and natural organic matter (NOM) that are precursors for chlorinated disinfection byproduct (DBP) formation. Nanofiltration (NF) systems can prevent DBP formation by removing color and NOM before chlorination. Research studies were conducted on Fall Lake water in Minnesota and dechlorinated potable water spiked with NOM in Ohio by using nanofiltration (Fyne process). Several types of tubular membranes with various molecular weight cutoffs were studied. The effectiveness of the Fyne process in producing safe drinking water was gauged by measuring the removal efficiency of total organic carbon, color, 2–3 micron particles, Bacillus subtilis as a surrogate for bacteria removal and MS2 bacteriophage as a surrogate for virus removal. Results of tests conducted under controlled laboratory conditions and field conditions indicated that Fyne process NF membranes could be used by sma...

A study was conducted to characterize bubble formation behavior of pressurized microporous hollow fiber membranes with water flow normal to the fiber axis. The influence of operating conditions such as water velocity (0.07 to 0.6 m/s), gas pressure (275 to 380 kPa), and gas fluxes (0.001 to 0.02 m/s) on bubble formation behavior was examined. Within these operating conditions, bubbles with a diameter smaller than a 100 μm were formed at the membrane surface. Coalescence occurred close to the membrane, which resulted in bubble diameters of 100 to 500 μm above the fiber. Bubble diameters increased with increasing gas flow rate and decreasing water velocity. These effects are expected as they both lead to increased local bubble density and rates of coalescence. Bubble formation behavior of the membrane was predicted well by an empirical equation determined for a single orifice by Ito and Hirata.

Small community systems that use surface water as a source of drinking water are frequently faced with elevated levels of naturally-occurring organic matter (NOM) that are not removed by conventional filtration methods. These residual levels of NOM may combine with chlorine used for disinfection and create disinfection byproducts (DBPs) potentially in excess of the regulatory limit for various DBPs. Frequently, additional treatment for removal of these DBPs is necessary to avoid noncompliance with the requirements of the Safe Drinking Water Act (SDWA). The formation of DBPs can be prevented by removing NOM, which acts as a precursor to DBP formation. This paper presents the results of field tests conducted on lake water using a nanofilter membrane, incorporating a method for cleaning the membrane using a foam ball. The system uses a tubular membrane with the ends connected to effectively form a single, long, membrane. The lake water is fed into the inside of the membrane tube and the filtrate is forced out, through the membrane into the membrane housing outlet. Using a timer, a foam ball is periodically passed through the inside of the membrane by reversing the flow direction. This foam ball serves to remove accumulated organic matter capable of fouling the membrane surface. This organic matter is flushed to drain as the foam ball passes through the inside of the tube. The system can be operated with the membrane reject water recycled to the system inlet or in a dead-end mode where no membrane reject water is produced until the system is foam ball cleaned. Tests were conducted in both modes of operation. The system requires no pretreatment of the feed water other than a coarse (3mm) screen to prevent large solids from entering the system. The effectiveness of the system in producing drinking water was gauged by measuring the turbidity, color, and particle counts of the system inlet and outlet. Tests were also performed using the aerobic spore Bacillus subtilis (B. subtilis) as a surrogate for bacteria removal. Notice: Any opinions expressed in this article are those of the author(s) and do not, necessarily, reflect the official positions and policies of the EPA. Any mention of products or trade names does not constitute recommendation for use by EPA. This document has been reviewed in accordance with EPA's peer and administrative review policies and approved for publication. 2096 World Environmental and Water Resources Congress 2009: Great Rivers © 2009 ASCE

The distribution of fluorescein between the anterior chamber and the anterior vitreous was measured in two groups of patients after oral administration: group I, extracapsular cataract extraction (ECCE) patients with intact capsule and posterior chamber intraocular lens (PC IOL) (n = 12); group II, intracapsular cataract extraction (ICCE) patients with anterior chamber IOL (AC IOL) (n =13). The fluorescein concentrations were measured by fluorophotometry and the penetration ratios were calculated. The penetration of fluorescein into the anterior vitreous was significantly less in the ECCE group (group I, penetration ratio=2.03 ± 1.00 × 10 −3 min −1 group II, penetration ratio=5.99 ± 4.89, × 10 −3 min −1 P

purpose: To determine the efficacy of vitamin E in the treatment of chemotherapy-induced mucositis in patients with malignancy. patients and methods: A randomized, double-blind, placebo-controlled study was performed to evaluate the efficacy of topical vitamin E in the treatment of oral mucositis in patients receiving chemotherapy for various types of malignancy. A total of 18 patients, 17 of whom had solid tumors and one with acute leukemia, were included in this study. Lesions were observed daily prior to and 5 days after topical application of either vitamin E or placebo oil. results: Six of nine patients receiving vitamin E had complete resolution of their oral lesions. In eight of nine patients who received placebo, complete resolution of their oral lesions was not observed. This difference is statistically significant ( p = 0.025 by Fisher's exact test). No toxicity was observed in this study. conclusion: These results suggest that vitamin E may be an effective therapy in patients with chemotherapy-induced mucositis.