摘要:

The study presents a realistic evaluation of the skin cancer risk associated with inorganic arsenic exposure through drinking water ingestion. The study uses a probabilistic risk assessment, which is recognized as an important tool in the characterization of health hazards associated with environmental toxin exposure. Compared to the approach with point values, this approach considers the uncertainty of its input values and evaluates realistic estimates of the health risks. Hence, the method provides useful information to the risk manager needing to make a wise decision regarding cancer risk associated with inorganic arsenic. Results have shown that the current level of inorganic arsenic in drinking water exceeds the current cancer risk criterion (10‐6) for the majority of general population. Hence, the study suggests that measures to reduce arsenic levels in water supplies should be considered. This information could be used to determine whether a drinking water standard associted with inorganic arsenic is health‐protective.

ISSN:1093-4529    

DOI:10.1080/10934529809376780

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Dextran has been determined in sugar juices from beet sugar refining processes by differential‐pulse cathodic stripping voltammetry (DPCSV) at the hanging mercury drop electrode (HMDE). Measurements were performed on diluted samples without previous treatment. The optimised procedure allowed the direct determination of dextran at the mg‐kg‐1level. The performance of the procedure is compared with the Roberts copper method.

ISSN:1093-4529    

DOI:10.1080/10934529809376781

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This study applies the neurogenetic model, i.e. a hybrid intelligent system combining genetic algorithm (GA) with artificial neural networks (ANN), to accurately predict effluent suspended solids concentrations from an enhanced biological phosphorus removal (EBPR) system under typical diurnal variation of municipal wastewater. Continuous‐flow pilot plant experiments with automatic monitoring and control facilities were performed to assess the model's applicability. The effluent suspended solids concentrations from the experiments closely corresponded to those predicted by the neurogenetic model developed herein.

ISSN:1093-4529    

DOI:10.1080/10934529809376782

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Pilot scale study using an anaerobic‐anoxic‐aerobic activated sludge process for the treatment of nitrogen and phosphorus removal from municipal wastewater in Taiwan was carried out. The BOD, TN and TP removal efficiency of 97.8%, 67.4% and 77.4% were achieved, respectively. Furthermore, effluent TN and TP were decreased to the lever of 8.7 mg/L and 1.13 mg/L, respectively. This showed that the biological treatment process used in this study could remove not only organic matter, but also nitrogen and phosphorus from municipal wastewater. The studies evaluating the rate of nitrification, denitrification, phosphorus release and phosphorus uptake were also performed. During steady state, average results of KN, KDN, KPRand KPUwere 0.736 mgNH4‐ N/gMLSS‐hr, 0.524 mgNO3‐N/gMLSS‐hr, 0.174 mgPO4‐P/gMLSS‐hr and 0.243 L/gMLSS‐hr, respectively.

ISSN:1093-4529    

DOI:10.1080/10934529809376783

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The performance of a pilot‐scale upflow anaerobic filter (UFAF) treating a dairy wastewater was studied for a period of 3 months. Results showed that the UFAF system achieved over 85% chemical oxygen demand (COD) and 90% biological oxygen demand (BOD5) removal efficiencies at an organic loading rate (OLR) of 6 kg COD/m3.d with a hydraulic retention time (HRT) of 20 hours. Percent methane in the biogas produced in the UFAF was found to be in a range of 75%‐85% with the corresponding methane yield of 0.32–0.34 m3CH4/kg COD removed. The system produced approximately 770 liters CH4/day. This would maintain all energy requirements of the feed and recirculation pumps and mixing. Approximately 35% of the energy requirement for maintaining the desired temperature of the pilot‐scale anaerobic filter column would also be recovered.

ISSN:1093-4529    

DOI:10.1080/10934529809376784

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new medium, Chromocult Coliform® Agar (CC agar) developed by E. Merck AG (Darmstadt, Germany) was compared with theStandard Methods, membrane filtration fecal coliform (mFC) medium for fecal coliform detection and enumeration. In the CC agar, non‐E. coli, fecal coliforms (Klebsiella, Enterobacter, andCitrobacter,), (KEC) were identified by the production of a salmon to red colour from p‐galactosidase (LAC) cleavage of the substrate Salmon‐GAL, whileE. coli, colonies were detected by the blue colour, produced by the cleavage of X‐glucuronide by β‐ glucuronidase (GUS). Statistically, there was no significant differences between fecal coliform counts obtained with the two media (CC agar and mFC agar) and two incubation procedures (2h‐37°C plus 22h‐44.5°, and 44.5°C) as determined by variance analysis. In our studyK coli, represented, on average 70.5–92.5% of the fecal coliform population. A high incidence of false negative KEC (19.5%) andE. coli, (29.6%) colonies was detected at 44.5°C. TwoK coli, GUS negative phenotype upon reinoculation into CC agar were GUS+. A total of 31 KEC LAC colonies were streaked ontoCC, agar and incubated at 37°C, 29 KEC strains that failed to produce β‐galactosidase at 44.5°C were able to produce the enzyme at 37°C. In our opinion the physiological condition of the fecal coliform isolates could be responsible for the non‐expression of P‐galactosidase and P‐glucuronidase activities at 44.5°C.

ISSN:1093-4529    

DOI:10.1080/10934529809376785

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:1093-4529    

DOI:10.1080/10934529809376769

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor