摘要:

Granular media filtration as applied to water and wastewater treatment is reviewed in terms of the types of filter media available, the alternative filter configurations, their modes of operation, and backwashing procedures. Filtration kinetics and mechanisms are reviewed, together with the hydraulic equations which have been developed to predict the pressure drop across a filter bed. Studies on the physical parameters which affect filter performance are reviewed. These include flow rate, particle size, filter media grain size, and particle number concentration. The effects of variation of chemical parameters, such as pH, ionic strength, and ionic species, on the surface chemistry of filter systems and filtration efficiency are reviewed. The use of polyelectrolytes in filtration, and possible mechanisms for their role as filtration aids are discussed. Studies on the influence of polymer structure, and the time and degree of mixing of the polymer with wastewater, prior to filtration, are reviewed. Methods of screening polymers and optimizing the dose for filtration applications are reviewed, together with other techniques which have been used in mechanistic studies of the process.

ISSN:0007-8999    

DOI:10.1080/10643388009381684

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Most research on the effects of petroleum in aquatic systems has concentrated on the immediate and short‐term toxic effects. This review collates and evaluates the results of research concerned with the effects of sublethal concentrations of petroleum hydrocarbons on aquatic organisms and to a lesser extent, ecosystems, and considers some of the implications for human health. The available information on quantities of petroleum hydrocarbons which are released into the sea as well as the concentration and types which occur in oceanic areas is presented. The various mechanisms by which hydrocarbons can enter different classes of aquatic organisms are outlined, as well as storage, metabolic, and excretion processes. This information is utilized in applying to petroleum hydrocarbons the mathematical modeling principles which have been developed during investigations of other environmentally persistent substances. In this context the behavior of petroleum hydrocarbons in food webs is considered, particularly the possibility of biological magnification. The available information on physiological and behavioral responses to sublethal concentrations of petroleum hydrocarbons is reviewed. In various areas the petroleum contamination of aquatic organisms used as food has occurred. The incidence of tainting in seafoods and the significance of human exposure to petroleum‐derived carcinogens is considered.

ISSN:0007-8999    

DOI:10.1080/10643388009381685

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor