Ex-situ soil washing of diesel contaminated soil using impinging stream reactors and selective soft self attrition

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dc.contributor.advisorLorenzen, L.en_ZA
dc.contributor.authorMare, Pieter Willemen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Process Engineering.
dc.date.accessioned2012-08-27T11:34:25Z
dc.date.available2012-08-27T11:34:25Z
dc.date.issued1999-12
dc.descriptionThesis (M.Ing.) -- University of Stellenbosch, 1999.
dc.description.abstractENGLISH SUMMARY: When considering oil spills, the focus has usually been on the pollution of water and the corresponding impact on the animals and habitat concerned. There is, however, another important aspect that has largely been neglected - soil contamination. The remediation of diesel contaminated soil, making use of soil washing techniques consisting of two technologies i.e., Impinging Stream Reactors and Selective Soft Self Attrition was studied in this project. The primary aim of these processes will be as a pre-treatment step for bioremediation in a complete treatment system, capable of reducing total remediation times considerably. The Impinging Stream Reactor (ISR) process uses a high pressure water jet to remove the diesel from the soil particles. The Selective Soft Self Attrition (SSSA) process uses a novel stirrer to stir a high density slurry (consisting of contaminated soil and water) resulting in interparticle scrubbing that removes the contaminant. Both processes were optimised with respect to all operating variables. The most important variable in soil remediation is the particle size distribution to be treated. Four samples of silica sand differing only in particle size fraction were used to represent the range from fine silty soils (42% -10 μm) to coarse sandy soils (+500μm). The Impinging Stream process was able to reduce diesel contamination levels in sandy soils by 96% (this corresponds to 2000 ppm, the most sensitive sites requiring levels below 200 ppm) but was not effective in treating silty soils. The Selective Soft Self Attrition process was able to reduce diesel contamination on sandy soils by 96% (to 2000 ppm) and silty soils by 94% (to 3000 ppm). Adding coarser sand as grinding agent to silty soils, reduces this value a further 2% (to below 2000 ppm). Analyses of the sand (after washing) were done by extracting the diesel with Methylene Chloride in a Soxhlet Extraction Unit, after which the solvent was evaporated and the residual diesel determined gravimetrically. Altering the evaporation part by slowing it down considerably, resulted in improved accuracy and repeatability. Gas chromatographic analyses of the diesel extracted from the sand was also done and showed that the components in diesel lighter than C 15 are being predominantly removed during these processes.
dc.description.abstractAFRIKAANSE OPSOMMING: Die fokus na 'n olieramp val gewoonlik op die aspekte van waterbesoedeling en die beskerming van die diere en habitat wat bedreig word. Daar is egter 'n ander belangrike aspek wat gewoonlik merendeels afgeskeep word - grondbesoedeling. Die remediasie van diesel besoedelde grond deur gebruik te maak van die twee tegnieke: Spuitreaktore en Selektiewe Sagte Self Attrisie is in hierdie projek bestudeer. Die hoofdoel van die twee tegnieke is om as vooraf behandeling vir bioremediasie te dien in 'n omvattende behandelings sisteem wat totale opruim tye sal verlaag. Die spuitreaktor proses maak van 'n hoe druk water stroom gebruik om die diesel vanaf die grondpartiikels te was. Die Selektiewe Sagte Self Attrisie proses gebruik 'n nuwe tipe roerder om 'n hoe digtheid flodder (bestaande uit die gekontamineerde grond en water) te roer wat 'n inter-partikel skuring veroorsaak en sodoende die kontaminant verwyder. Beide prosesse is geoptimiseer ten opsigte van alle bedryfsveranderlikes. Die belangrikste veranderlike in grondremediasie is die partikel grootte verspreiding van die grond wat behandel moet word. Vier verskillende monters silika sand (wat slegs in partikel grootte verspreiding verskil) is gebruik om die spektrum vanaf fyn leemgrond (42% - 10 μm) tot growwe sanderige grond (+ 500 μm) te verteenwoordig. Die spuitreaktor proses het 96% van die diesel op die sanderige grond verwyder (dit stem ooreen met 2000 ppm, die mees sensitiewe areas benodig egter vlakke laer as 200 ppm), maar was nie suksesvol in die behandeling van leemgrond nie. Die Selektiewe Sagte Self Attrisie proses het 96% (2000 ppm oorblywend) van die diesel op die sanderige sand verwyder en 94% (3000 ppm oorblywend) van die diesel op die leemgrond. Deur growwe sand by die leemgrond te voeg is 'n verdere 2% diesel verwyder (2000 ppm oorblywend). Analise van die sand (na die was proses) is uitgevoer deur die diesel met behulp van Metileen Chloried the ekstraheer in 'n Soxhlet Ekstraksie Eenheid waarna die oplosmiddel afgedamp is en die oorblywende diesel gravimetries bepaal is. Deur die verdamping van die oplosmiddel te vertraag was dit moontlik om die akkuraatheid en herhaalbaarheid van die analises te verbeter. Gas chromatografiese analise, van die diesel wat geekstaheer is, het getoon dat componente ligter as C 15 by voorkeur verwyder word gedurende die wasproses.
dc.description.versionMaster
dc.format.extent1 v. (various pagings) : ill.
dc.identifier.urihttp://hdl.handle.net/10019.1/51268
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch University
dc.rights.holderStellenbosch University
dc.subjectSoil pollutionen_ZA
dc.subjectSoil remediationen_ZA
dc.subjectOil spillsen_ZA
dc.subjectOil pollution of soilsen_ZA
dc.subjectDissertations -- Chemical engineering
dc.titleEx-situ soil washing of diesel contaminated soil using impinging stream reactors and selective soft self attritionen_ZA
dc.typeThesisen_ZA
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