Sewerage System: Maintenance Technologies

Ketoconazole is an imidazole antifungal drug belonging to the class II of Biopharmaceutic Classification System. Maintenance of gastric acidity is essential for adequate dissolution and absorption of ketoconazole. Concurrent administration of antacid and antiulcer preparations decreases the oral absorption of ketoconazole often causing therapeutic failure. The aim of this study was to evaluate whether a self-emulsifying formulation of ketoconazole would be able to overcome the pH dependent dissolution and oral bioavailability. Self-emulsifying drug delivery system (SEDDS) was prepared after selecting the oil, surfactant and co-surfactant by solubility analysis. Optimum ratio of the components was finalized on the basis of drug content, self-emulsification and mean droplet diameter. The effect of pH on dissolution was studied in comparison to the pure drug. Oral bioavailability was determined in comparison to aqueous suspension in rats and the effect of co-administration of ranitidine hydrochloride solution and a commercially available liquid antacid preparation was studied. The optimized formulation containing 20% Capryol 90 and 40% each of Carbitol and Tween 80, exhibited 100% drug release regardless of the pH whereas the pure drug exhibited a highly pH dependent dissolution. The AUC0-24 resulted with oral administration of the SEDDS formulation was about 34%, 43% and 60% higher compared to the aqueous suspension when administered alone, administered with ranitidine and administered with antacid respectively. The results of the present study demonstrate that self-emulsifying formulations can be utilized for oral delivery of weakly basic drugs like ketoconazole which exhibit pH dependent dissolution.

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CW Measurement System. Software System Maintenance Manual.

10.21236/ada151622 ◽

1982 ◽

Author(s):

R. Nelson ◽

P. Lindsey

Keyword(s):

Measurement System ◽

Software System ◽

System Software ◽

System Maintenance

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Wastewater Treatment and Disposal in the City of Dubrovnik

Water Science & Technology ◽

10.2166/wst.1989.0006 ◽

1989 ◽

Vol 21 (1) ◽

pp. 55-66

Author(s):

J. Margeta ◽

J. Pupovac ◽

B. Ivančić

Keyword(s):

Wastewater Treatment ◽

Environmental Protection ◽

Rapid Development ◽

Specific Method ◽

Wastewater Disposal ◽

Sewerage System ◽

Seaside Resort ◽

Coastal Sea ◽

Treatment And Disposal ◽

The City

Dubrovnik is the most popular tourist seaside resort in Yugoslavia. The rapid development of tourism has necessitated appropriate environmental protection, particularly with regard to the coastal sea. Consequently, the city has constructed a plant for the treatment of wastewater and a submarine outfall. The characteristics of the sewerage system and the coastal sea meant that the wastewater disposal system required a specific method of construction and treatment. This paper presents the system adopted for Dubrovnik and the methodology used to choose the system. Special attention is paid to the problems and drawbacks which occurred during design and operation of the system, as well as to the measures undertaken afterwards for reconstruction of the system.

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Waste stabilization ponds in France: a report on fifteen years experience

Water Science & Technology ◽

10.2166/wst.1995.0465 ◽

1995 ◽

Vol 31 (12) ◽

pp. 91-101 ◽

Cited By ~ 6

Author(s):

Y. Racault ◽

C. Boutin ◽

A. Seguin

Keyword(s):

Load Level ◽

Organic Load ◽

Nitrogen And Phosphorus ◽

Waste Stabilization Ponds ◽

Sewerage System ◽

System Type ◽

Stabilization Ponds ◽

Waste Stabilization ◽

Output Load

In 1992, a survey was conducted on the performance of waste stabilization ponds in France. The data selected come from a sample of 178 ponds, with an average capacity of 600 p.e., throughout France. For each plant, one or several input--output load measurements over a 24-h period are available. The average organic load level received is approximately 25 kg BOD/ha.d, representing 50% of the nominal load. The quality of the treated water is presented based on the type of sewerage system feeding the ponds. The results appear dispersed, however; in 70% of the cases the concentrations in COD and BOD on filtered samples are under 120 mg/l and 40 mg/l, respectively, and the concentration in TSS under 120 mg/l (discharge standards in France for waste stabilization ponds). The reductions in nitrogen and phosphorus nutrients are on average from 60% to 70%. The influence of different parameters (sewerage system type, organic load, season, age of plant, etc.) was studied. The results appear noticeably worse when the ponds receive wastewater from a strictly separate sewerage system.

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Transport of chlorinated hydrocarbons between sewage and sewer atmosphere

Water Science & Technology ◽

10.2166/wst.1996.0476 ◽

1996 ◽

Vol 34 (3-4) ◽

pp. 557-564 ◽

Cited By ~ 2

Author(s):

Bettina S. Haas ◽

Reimer Herrmann

Keyword(s):

Mass Transfer ◽

Aromatic Compounds ◽

Chlorinated Hydrocarbons ◽

Transfer Coefficients ◽

Mass Transfer Coefficients ◽

Sewerage System ◽

Mass Fluxes ◽

Single Compound

Sewage containing volatile contaminants is a potential VOC-source in cities. Thus we tried to evaluate volatilization out of the sewerage system by measurements of contaminants in sewer gas and sewage. Our results from a medium sized town with little industry showed that sewer gas is mainly contaminated with alkanes, small aromatic compounds and chlorinated hydrocarbons. For three chlorinated hydrocarbons (chloroform, trichloroethene, tetrachloroethene) we determined mass transfer coefficients out of sewage and used these data to estimate mass fluxes from sewage and emissions out of the sewerage system for two sewer stretches. Considerable emission of chlorinated hydrocarbons from sewage, i.e. fluxes of some 10 to 100 g per m2·d, occurred only when the contaminant input via sewage was between some g and mg per litre for a single compound. For concentrations that were about 3 orders of magnitude less, emissions were negligible.

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