Home  About us  Contact
 

Water Treatment Process (water + treatment_process)

Distribution by Scientific Domains
Life Sciences60%

Selected Abstracts

Profiling bacterial survival through a water treatment process and subsequent distribution system

JOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2005
D. Hoefel
Abstract Aims:, To profile fractions of active bacteria and of bacteria culturable with routine heterotrophic plate count (HPC) methods through a typical water treatment process and subsequent distribution system. In doing so, investigate how water treatment affects both bacterial abundance and diversity, and reveal the identities of active bacteria not detected by traditional HPC culture. Methods and Results:, Profiling active fractions was performed by flow cytometric cell sorting of either membrane-intact (BacLightTM kit) or enzymatically active (carboxyfluorescein diacetate, CFDA) bacteria, followed by eubacterial 16S rDNA-directed PCR and denaturing gradient gel electrophoresis (DGGE). Water treatment significantly reduced active bacterial numbers detected by the BacLightTM kit and CFDA assay by 2·89 and 2·81 log respectively. Bacterial diversity was also reduced from >20 DGGE bands in the active fractions of reservoir water to only two bands in the active fractions of finished water. These two bands represented Stenotrophomonas maltophila, initially culturable by HPC, and a Burkholderia -related species. Both species maintained measurable traits of physiological activity in distribution system bulk water but were undetected by HPC. Conclusions:, Flow cytometric cell sorting with PCR-DGGE, to assess water treatment efficacy, identified active bacteria from a variety of major phylogenetic groups undetected by routine HPC. Following treatment S. maltophila and a Burkholderia -related species retained activity and entered distribution undetected by HPC. Significance and Impact of the Study:, Methods used here demonstrate how water treatment operators can better monitor water treatment plant efficacy and assess distribution system instability by the detection and identification of active bacteria recalcitrant to routine HPC culture. [source]

Process monitoring for continuous process with periodic characteristics

JOURNAL OF CHEMOMETRICS, Issue 2 2004
Yangdong Pan
Abstract Application of conventional statistical monitoring methods to periodic processes can result in frequent false alarms and/or missed faults due to the non-stationary behavior seen over a period. To address this problem, we propose to identify and use a stochastic state space model that describes the statistical behavior of changes occurring from period to period. This model, when retooled as a periodically time-varying model, can be used for on-line monitoring and estimation with the aid of a Kalman filter. The same model can also be used for inferential estimation of the variables that are difficult or slow to measure on-line. The proposed approach is applied to a simulation benchmark of a waste water treatment process, which exhibits strong diurnal changes in the feed stream, and is compared against the principal component analysis (PCA) and partial least squares (PLS) methods. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Nanotechnologies: Tools for sustainability in a new wave of water treatment processes

INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006
Jean-Yves Bottero
Abstract In the environmental technology industry alone, nanomaterials will enable new means of reducing the production of industrial wastes, using resources more sparingly, remediating industrial contamination, providing potable water, and improving the efficiency of energy production. This paper discusses three new kinds of nanotechnology materials that should be developed in the future: Membranes, oxidants, and adsorbents. Nanoscale control of membrane architecture may yield membranes of greater selectivity and lower cost in both water treatment and water fabrication. Fullerene-based oxidant nanomaterials such as C60 have a high electron affinity and reactivity, and are capable of producing reactive oxygen species such as singlet oxygen and superoxides. Fullerenes might be used in engineered systems to photocatalytically oxidize organic contaminants, or inhibit or inactivate microbes. The ability to tailor surfaces can help to increase adsorbing capacities or recognize specific contaminants. The potential environmental risks are that nanomaterials could interact with biota and that their toxicity adversely may affect ecosystems. As nanochemistry emerges as an important force behind new environmental technologies, we are also presented with the responsibility of considering the environmental implications of an emerging technology at its inception and taking every precaution to ensure that these technologies develop as tools of sustainability rather than becoming future liabilities. [source]

Bactericidal effect of chlorine on Mycobacterium paratuberculosis in drinking water

LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2001
L.B. Whan
Aims:,One possible route of transmission of Mycobacterium paratuberculosis from cattle to humans is via contaminated water supplies. The aim of this work was to determine whether this organism can survive standard water treatment processes. Methods and Results:,Two strains of M. paratuberculosis (bovine strain, NCTC 8578 and human strain Linda, ATCC 43015) were subjected to various chlorine concentrations (0·5, 1·0 and 2·0 ,g ml,1) for 15 and 30 min. Chlorine test solutions were made up in two types of water, sterile water that had been deionized and subjected to reverse osmosis (DRO) and DRO water containing MgCl2, CaCl2, NaHCO3 and bovine serum albumin (0·3% w/v), the latter to mimic conditions the organism would experience in commercial water treatment operations. Conclusions:,The data showed that when initial inoculum levels were high (106 cfu ml,1) neither M. paratuberculosis strain was completely killed at the free chlorine concentrations and contact times applied. Log10 reductions in the range 1·32,2·82 were observed. The greatest log10 reduction in cell numbers (2·82 and 2·35 for the bovine and human strains, respectively) was observed at the highest chlorine concentration (2 ,g ml,1) and longest contact time (30 min). Significance and Impact of the Study:,This work highlights the need for further research into the survival of M. paratuberculosis during water treatment. [source]