摘要:

This review has considered the feasibility of applying current microbial treatment techniques to the remediation of former gasworks. Success would appear dependent upon the contaminants of interest being biodegradable and an effective means of implementation. Contaminants of concern at gasworks include PAH, phenols and cyanides. Laboratory and field studies suggest that these contaminants are biodegradable although little data exists with respect to mixtures in the form present at gasworks. Further research is recommended in this respect. Subsurface investigations of gasworks have revealed an extremely heterogeneous environment which suggests that current in situ remedial techniques may be unsuitable. Techniques that excavate and homogenise the contamination prior to treatment may improve the chances of successful remediation. Pilot studies appear successful but future research should emphasise a mass balance approach where the significance of non biological degradative mechanisms can be assessed. Contaminated groundwaters appear amenable to treatment in surface reactors. The success of overall remediation will however be dependent on the efficiency of the hydraulic withdrawal system used. The implementation of such a scheme should only be undertaken with a clear understanding of the limitationsofthis technology.

ISSN:0959-3330    

DOI:10.1080/09593339309385261

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Accurate spectral measurements of solar ultraviolet radiation are essential to an understanding of the photochemical and biological effects of ozone depletion. The analysis of spatial and temporal variations in ultraviolet fluxes will depend on the collation of spectra from many independent laboratories. However, results from diverse instruments operated in isolation may not be consistent with each other. To investigate the compatibility of different designs of spectroradiometer, a blind trial of six distinct instrument types was carried out at a suburban site in Greece. Comparisons were performed in daylight, and with tungsten lamps indoors. Excellent agreement was obtained in the relative spectral response of the instruments, but their absolute lamp calibrations varied, and did not generally agree with results from the daylight experiments. Simultaneous spectral scans by all instruments revealed discrepancies attributable to stray light, bandwidth, and cosine response, which would not otherwise have been apparent. The relative merits of the instrument characteristics are discussed.

ISSN:0959-3330    

DOI:10.1080/09593339309385262

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Pilot scale studies were conducted to investigate the effect of oxidation at various stages of water treatment process. Impact of pre‐ and postoxidation (before coagulation and after filtration, respectively), on the formation of disinfection by‐products (DBPs) and assimilable organic carbon (AOC) was investigated. Based upon the oxidant (ozone or ozone + hydrogen peroxide) dosages evaluated, no consistently significant differences, in terms of DBP reduction and AOC formation, were observed in pre‐ vs. postoxidation scenarios. The ozone dosage required in postoxidation was found to be less than half of that required in preoxidation to achieve similar DBP reductions and AOC results. Addition of hydrogen peroxide along with ozone did not result in consistently improved treatment performance. Bench and pilot scale studies were conducted to investigate the effect of ozone oxidation pathway on the reduction of DBPs. It was found that, while ozone alone was not particularly effective for long term reduction of DBPs, ozonation in the presence of radical scavenging bicarbonate resulted in statistically significant higher reduction of DBP precursors.

ISSN:0959-3330    

DOI:10.1080/09593339309385263

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Long‐term impacts of acidic depositions on soils can be predicted with coupled applications of acid deposition models and approaches to assess soil acidification. Soil acidification assessment can be achieved by using the following approaches:I.Mechanistic modellingII.Experimental acid buffering capacity (ABC) methodIII.Qualitative evaluations

ISSN:0959-3330    

DOI:10.1080/09593339309385264

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In this paper, a numerical method ‐ Spline Function has been used to determine the parameters of adsorption fixation kinetics onto granular activated carbon surface (PICA NC60) in a range of aromatic compounds in batch reactor. This description allows us to examine the validity of Adams‐Bohart model (AB). The test compounds concern Benzaldehyde, Phenol, p‐Nitrophenol, Aniline, p‐Cresol and Nitrobenzene. It is obvious from calculations that AB equation is only to be applied in the case of weak concentration. The surface fixation process seems to approximate mass transfer through external film surrounding each adsorbent particle surface in weak initial concentration. A modified kinetic equation (ABM) can be derived from experimental data, being agreement with experiments. The parameter kfis connected with those of AB or ABM equation. Adsorption kinetic characteristics for aromatic compounds may be classed in three groups.

ISSN:0959-3330    

DOI:10.1080/09593339309385265

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The removal of nickel ions from aqueous solutions, using fly ash, a cheap industrial by‐product, was investigated. Its addition to the solution raised the pH, effectively removing the totality of the nickel ions. The removal may be attributed, depending upon the dispersion pH, partly to adsorption but mainly to precipitation. The fly ash performance was compared to that of other adsorptive materials (activated carbon and a synthetic zeolite). The synthetic zeolite was more efficient in removing the nickel ions, especially at low pH values, but is evidently a more costly material.

ISSN:0959-3330    

DOI:10.1080/09593339309385266

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper addresses the heavy metal pollution development in Jacarepaguá coastal lagoon, by means of sediment core analysis. Sedimentation rate and sediment geochronology are also examined. Statistical multivariate procedure (factor analysis) is employed in order to investigate the mechanisms which may regulate the behaviour of trace metals in the sediment environment.

ISSN:0959-3330    

DOI:10.1080/09593339309385267

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0959-3330    

DOI:10.1080/09593339309385260

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor