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Pretreatment and biodegradation of wastewater from a textile dyeing and finishing industry /Weber, Michelle Lynn, January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 164-172). Also available via the Internet.
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Characterization and engineering of Bacillus megaterium AS-35, for use in biodegradation of processed olive wastewaterVan Schalkwyk, Antoinette January 2005 (has links)
<font face="Times New Roman"><font face="Times New Roman">
<p align="left">The popularization and health benefits associated with the &ldquo / Mediterranean diet&rdquo / saw a world wide increase in the production and consumption of processed olives and olive oil. During the brining of table olives large quantities of processed olive waste water is seasonally generated. This blackish-brown, malodours liquid is rich in organic and phenolic compounds, which cause environmental problems upon discarding. Currently, processed wastewater is discarded into large evaporation ponds where it poses serious environmental risks. The biodegradation of organic substrates present in the olive wastewater is inhibited by the high concentrations of phenolic compounds. <font face="Times New Roman">In order to identify organisms which could potentially be used in the bioremediation of olive wastewater, 36 microbial strains were isolated from evaporation ponds in the Boland region of South Africa. Twenty five isolates were capable of growth on 50% olive wastewater and their bioremediation potential as well as their ability to produce valuable intermediate compounds were subsequently characterized. Based on the RPHPLC results, which showed that a number of chemical intermediates were produced in fermentation of olive wastewater, isolate AS-35 was selected for further analysis. Strain AS-35, identified as a </font><font face="Times New Roman"><em>Bacillus megaterium,</em> </font><font face="Times New Roman">was significantly influenced by the exposure to olive waste. The total cellular protein profile, generation time and cellular morphology of this isolate were dramatically affected by the introduction of olive waste. <font face="Times New Roman">This study investigated the differential gene display of </font><font face="Times New Roman"><font face="Times New Roman"><em>Bacillus megaterium</em></font> </font><font face="Times New Roman">following exposure to olive wastewater. Proteomic and transcriptomic differences of the organism cultured in nutrient rich LB and olive wastewater were compared. These results indicated that AS-35 expressed genes involved in glycolysis, tryptophan and nucleotide synthesis as well as the chaperones GroEL and DnaK during its growth in LB. In contrast, genes induced following the abolishment of glucose dependent catabolite repression, genes involved in biotin synthesis and ß / -oxidation of fatty or organic acids as well as a gene whose expression is regulated by stress induced s</font><font face="Times New Roman" size="1">B</font><font face="Times New Roman">-dependent regulon were expressed during olive waste growth.</font></font></p>
</font></font>
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A pre-screening tool for the anaerobic treatment of complex industrial effluents and wastewaters.Naidoo, Dinesh. January 2003 (has links)
The objective of this investigation was to assess the potential of a titration bioassay i.e.: The
Methanogenic Activity and Inhibition Analyser (MAlA), to determine the biodegradability of
complex industrial effluents and wastewaters. Specifically, the project aimed to provide an
alternative experimental method to the serum bottle method so that hazardous effluents can be
pre-screened for treatment in under-utilised anaerobic digesters at sewage treatment plants in
KwaZulu-Natal, South Africa. This study also aimed to provide a protocol and a simple
mathematical model as experimental tools that could contribute to the development of future
pre-screening studies.
MAIA was used to conduct biodegradability and toxicity studies on semi-hazardous landfill
leachate and textile size effluent. Thereafter, selected studies were repeated using a
conventional screening method i.e.: serum bottle method. The investigation with MAlA
revealed that both effluent substrates had potential for anaerobic treatment. However, the
studies highlighted certain intrinsic limitations of the MAIA apparatus to effectively
pre-screen complex substrates. The existing titrimetric system is too coarse to accurately track
the biochemical pathways leading from the breakdown of complex compounds to methane
gas production. Further, temperature interferences and gas phase diffusion limitations
associated with the existing design make the assessment of activity difficult.
The titrimetric method is comparable to the serum bottle method only if a qualitative
assessment of toxicity and biodegradability is needed. However, the titrimetric method
produces results in a much shorter period of time compared to the serum bottle method.
Evaluated in this way the titrimetric method is the better alternative. However, the current
system cannot challenge the reliability of the serum bottle method to provide good
quantitative results.
A mathematical model was developed which is much less detailed than the existing one
provided by Remigi (2001). It comprises only two significant anaerobic processes namely
hydrolysis and acetogenesis. Simulation trials have suggested that the model is a necessary
and beneficial component ofthe titrimetric pre-screening protocol.
This investigation has also led to the development of a more refined operating manual for
MAIA.The manual provides a step-wise method for the preparation and conduction of
pre-screening tests. Specifically, it highlights the need for a suitable biomass acclimation
period and the importance ofnutrient use for better pre-screening assessments. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.
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Development of a bioreactor system using a pine bark matrix for the removal of metal ions from synthetic aqueous solutions.Van Zuydam, Jason Peter. 06 November 2013 (has links)
Many industries use, or produce, metal-containing solutions which must be
treated for reuse or discharge to sewer. One such treatment is biological and both living and dead materials have been investigated for the abstraction of metal ions from solution. Studies on systems containing only a single biosorbent are well documented, and mostly involve optimisation of biosorption capacities and metal uptake rates through modification of Biological Support Particle (BSP) size and surface characteristics. Literature on dual biosorbent studies is sparse. The commercial application of biosorption technology in wastewater treatment remains largely unexplored and unexploited. The primary objective here was to assess the potential of forced-upflow packed-bed bioreactors, containing dual biological sorbents, for treating a synthetic wastewater containing copper, zinc and cadmium, at both laboratory- and pilotscale.
Pine bark was selected as BSP since it is an abundant, relatively cheap,
agricultural waste product in South Africa, and is known to sorb metal ions. Initial experiments aimed to optimise biofilm development on the pine bark surfaces, since microbial biomass is also known to sequester metal ions. Systems comprising either one, or both, these biosorbents were compared for their efficiency in metal removal. The effects of type, size, and state of decomposition, of the pine bark, the addition of supplementary nutrients (Voermolas) and the mixing conditions, on the metal biosorption capacity and reaction kinetics of the systems were also studied. All experiments were conducted at an initial metal concentration of 100mg.ℓ⁻¹with both composted and uncomposted pine bark as BSP. The former supported
microbial colonisation and resisted biofilm sloughing, but degraded rapidly
causing engineering difficulties. Uncomposted pine bark showed the same ability, but was also physically more robust.
Organic compounds leached from the pine bark did not hinder microbial
colonisation of the BSP; rather they served as additional nutrients. Literature studies suggest that these compounds would not significantly compromise the COD or increase the toxicity of the final effluent. Biofilms developed without supplementary nutrients, but Cd²⁺ and Zn²⁺ were sorbed more effectively in bioreactors containing Voermolas (39% and 38% Cd²⁺ removal, 36% and 32% Zn²⁺ removal, in 0.2% and 0.1% Voermolas solutions respectively) than in unsupplemented systems (25% Cd²⁺ removal and 20% Zn²⁺ removal). Conversely, Cu²⁺ was removed most efficiently in the absence of supplementary nutrients. Based on biosorption of the target metal ions, 0.1% (v/v) Voermolas was the most effective concentration of supplementary nutrients.
Raw, un-colonised pine bark nuggets (16-24mm), and plastic bioballs
(commercially available, bespoke BSP), were compared in laboratory-scale
bioreactors by measuring the decrease in residual metal ion concentrations over time, and changes in the solution pH. These experiments showed that the two BSPs did not differ significantly in their performance as a support matrix, or as a metal sorbent (30.6% and 32.6% of metal ion remained in solution when using bioballs and pine bark respectively). However, the presence of a biofilm on both these BSPs, improved the overall performance of the bioreactors significantly (for the bioball BSP, residual metal ion levels decreased from 30.6%, in the absence of a biofilm, to 11.0% with a biofilm present. Similarly, for the pine bark BSP, residual metal ion levels decreased from 32.6%, in the absence of a biofilm, to
7.3% with a biofilm present). A cost comparison of the two BSPs showed that raw pine bark nuggets were available at less than 0.1% of the cost of the bioballs. At pilot-scale, modelled kinetic data compared poorly with experimentally determined results, but minimum residual metal concentrations for Cu (1.7mg.ℓ⁻¹) and Zn (4.2 mg.ℓ⁻¹) were below South African (eThekwini Municipality) regulatory limits for discharge to sewer (5mg,ℓ⁻¹ for both), and sea outfall (3mg.ℓ⁻¹ Cu and 20mg.ℓ⁻¹ Zn). However, for Cd the final residual metal concentration (5.6mg.ℓ⁻¹) was above the regulatory discharge threshold for any receiving system.
Although some of the effluents from the system investigated could not be legally released into the municipal sewer system without further remediation, the study showed that a system combining living and dead biomass in a single reactor is capable of significantly reducing dissolved metal concentrations in synthetic wastewaters without temperature or pH adjustment. Furthermore, such a system can operate at pilot-scale, where a pine bark matrix represents a significant cost saving over conventional plastic BSPs. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
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Determining the capability of a vegetation cover to limit effluent leaching from a waste impoundment.Morgan, Gary Duwayne. January 2009 (has links)
A final cover on a waste impoundment is the main physical barrier between the waste impoundment and the environment designed to protect against physical, chemical and biological factors isolating the waste from the atmospheric environment. Since the early 1990‟s regulators in the United States have started accepting vegetation covers in lieu of the prescriptive covers. Currently in South Africa, data that provide field performance comparisons of alternative vegetation covers are few or non-existent; hence a research program was undertaken by an industrial corporation in South Africa to determine the potential use of vegetation covers. In proposing a practical way forward, the Company (AECI Limited) reached an understanding with the Regulators that a vegetated evapotranspiration (ET) cover, would be acceptable provided that its performance in limiting surface water infiltration (and subsequent leaching) could be quantitatively demonstrated.
The overall object of this research was to determine the capability of vegetation cover to limit effluent leaching from a waste impoundment. Analysis of the following sub-objectives were required to address and give answers to this study (1) determine, as accurately as possible a climatic water balance on the vegetation covers, (2) determine the geohydrological properties of the material of the waste impoundment, (3) determine the fate of the water i.e. proportion reused via evapotranspiration as opposed to the proportion infiltrating the waste body beneath the root zone and (4) determine the leaching potential below the waste.
The study identifies and evaluates the climatic (above ground) and geohydrological (sub-surface) parameters used to estimate the water balance of the materials for a waste impoundment. The study then utilizes these parameters at the respective sites in a finite-element model, called the HYDRUS-2D model, to simulate the water balance of the material. The simulated water balance results were then compared against collected field data, which provide the evidence of the efficiency of a vegetation cover to limit effluent from the impoundment. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
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Characterization and engineering of Bacillus megaterium AS-35, for use in biodegradation of processed olive wastewaterVan Schalkwyk, Antoinette January 2005 (has links)
<font face="Times New Roman"><font face="Times New Roman">
<p align="left">The popularization and health benefits associated with the &ldquo / Mediterranean diet&rdquo / saw a world wide increase in the production and consumption of processed olives and olive oil. During the brining of table olives large quantities of processed olive waste water is seasonally generated. This blackish-brown, malodours liquid is rich in organic and phenolic compounds, which cause environmental problems upon discarding. Currently, processed wastewater is discarded into large evaporation ponds where it poses serious environmental risks. The biodegradation of organic substrates present in the olive wastewater is inhibited by the high concentrations of phenolic compounds. <font face="Times New Roman">In order to identify organisms which could potentially be used in the bioremediation of olive wastewater, 36 microbial strains were isolated from evaporation ponds in the Boland region of South Africa. Twenty five isolates were capable of growth on 50% olive wastewater and their bioremediation potential as well as their ability to produce valuable intermediate compounds were subsequently characterized. Based on the RPHPLC results, which showed that a number of chemical intermediates were produced in fermentation of olive wastewater, isolate AS-35 was selected for further analysis. Strain AS-35, identified as a </font><font face="Times New Roman"><em>Bacillus megaterium,</em> </font><font face="Times New Roman">was significantly influenced by the exposure to olive waste. The total cellular protein profile, generation time and cellular morphology of this isolate were dramatically affected by the introduction of olive waste. <font face="Times New Roman">This study investigated the differential gene display of </font><font face="Times New Roman"><font face="Times New Roman"><em>Bacillus megaterium</em></font> </font><font face="Times New Roman">following exposure to olive wastewater. Proteomic and transcriptomic differences of the organism cultured in nutrient rich LB and olive wastewater were compared. These results indicated that AS-35 expressed genes involved in glycolysis, tryptophan and nucleotide synthesis as well as the chaperones GroEL and DnaK during its growth in LB. In contrast, genes induced following the abolishment of glucose dependent catabolite repression, genes involved in biotin synthesis and ß / -oxidation of fatty or organic acids as well as a gene whose expression is regulated by stress induced s</font><font face="Times New Roman" size="1">B</font><font face="Times New Roman">-dependent regulon were expressed during olive waste growth.</font></font></p>
</font></font>
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Isolation and characterisation of lipolytic bacteria and investigation of their ability to degrade fats, oils and grease in grain distillery wastewaterHendricks, Ashley Alfred 04 1900 (has links)
Thesis (MSc Food Sc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The large volumes of effluent water generated by distillery industries is an issue of
great concern as it contains pollutants that must be treated according to environmental
legislation. It has been reported that grain distillery wastewater (GDWW) is high in fats, oils
and greases (FOG) that can be reduced by treating with suitable microorganisms. The
objective of this study was to investigate the biodegradability of FOG in GDWW. This was
done by isolating lipolytic bacteria from soil, which was situated close to the GDWW
treatment plant at a distillery in Wellington, South Africa. These isolates were screened for
lipolytic activity on various fat substrates. Secondly, the most desirable isolates were
subjected to batch biodegradation trials using GDWW as substrate and tested for their
ability to biodegrade FOG. Each of the four isolates, Pseudomonas fluorescens (1),
Pseudomonas luteola (2), Stenotrophomonas maltophilia (3) and Bacillus licheniformis (4)
were screened on three types of media: DifcoTM Spirit Blue Agar with Tributyrin (SBA-Tri);
Victoria Blue B Agar with Cotton Seed Oil (VBB-CSO); and Victoria Blue B Agar with
GDWW (VBB-GDWW) at different temperatures (25°C, 30°C, 37°C and 50°C) to
determine optimal enzyme activity for lipolysis. Lipolysis was taken as positive when
growth of dark blue colonies was formed or by the formation of a clear zone around the
colony. Lipolysis was observed at all the aforementioned temperatures for P. fluorescens,
P. luteola and S. maltophilia. Bacillus licheniformis failed to show any lipolytic activity at
50°C on the SBA-Tri. A decrease in lipolytic (clear) zone was observed at an increase in
temperature from 25°C to 37°C for P. fluorescens. When VBB-GDWW was used as lipid
substrate, isolates failed to indicate any clear zone of lipolysis, however, growth was
present for all isolates in the form of a dark blue zone around colonies, which were also
positive for lipolytic activity.
Three lipolytic bacteria (P. luteola, S. maltophilia, and B. licheniformis)
isolated from the above study were subjected to GDWW of various FOG concentrations
(70 – 211 mg.L-1). These isolates were allowed to acclimatise to GDWW during a batch
biodegradation period (18 – 21 d) at 37°C. Bacillus licheniformis showed the highest FOG
reduction of 83% after 18 d exposure. All the strains showed that an initial acclimatisation
phase improved the biodegradation of the FOG. A fatty acid profile was obtained for each
batch biodegradation trial after the acclimatisation phase. It was found that these strains
either biodegraded the fatty acids (FAs) or, as in the case of P. luteola, formed myristic
and pentadecyclic acids from free FAs. The formation of FAs may have occurred through a process of inter-esterification. It was also found that certain precursors such as palmitoleic
acid might be formed under aerobic or anaerobic conditions.
In this study it was shown that biodegradation of FOG can be improved by an initial
acclimatisation period. Single cultures with the desirable properties can be used to lower
the FOG in GDWW and need not be used in mixed cultures that could produce inhibitory
components that would otherwise upset the biodegradation activity of isolates present.
Bacillus licheniformis could be used as a FOG-degrading isolate during the treatment of
wastewaters high in FOG. However, future studies should focus on bioaugmenting the
FOG degrading bacteria from this study with other strains to monitor its activity and ensure
survival and activity in larger scale studies. / AFRIKAANSE OPSOMMING: Die groot volumes afloopwater wat opgelewer word deur die distilleer-industrie is ‘n
kwessie wat groot kommer wek aangesien dit groot hoeveelhede besoedelende stowwe
bevat. Daarom moet dit, volgens omgewingsverwante wetgewing, behandel word. Daar is
voorheen gerapporteer dat graandistillerings-afloopwater (GDAW) hoog is in vette, olies
en ghries (VOG) en dat hierdie VOG verminder kan word deur die GDAW te behandel met
toepaslike mikroörganismes. Die oorhoofse doelstelling van hierdie studie was om die bioafbreekbaarheid
van die VOG in GDAW te ondersoek. Dit is eerstens gedoen deur
lipolitiese bakterieë uit grond wat naby ‘n graandistillerings-aanleg (Wellington, SuidAfrika)
geleë is, te isoleer. Verskeie vetsubstrate is gebruik om hierdie isolate vir lipolitiese
aktiwiteit te toets. Tweedens is die verkose isolate getoets vir lipolitiese aktiwiteit deur
gebruik te maak van lot-bio-afbreekbaarheidsmetode. Tydens hierdie metode is GDAW as
substraat gebruik en die verskillende bakterieë se vermoë om VOG af te breek is getoets.
Om die optimale ensiemaktiwiteit vir lipolise van elk van die vier isolate nl. Pseudomonas
fluorescens (1), Pseudomonas luteola (2), Stenotrophomonas maltophilia (3) en Bacillus
licheniformis (4), vas te stel, is elk getoets op drie verkillende media: “DifcoTM Spirit Blue
Agar” met Tributirien (SBA-Tri); “Victoria Blue B Agar” met Katoensaadolie (VBB-KSO); en
“Victoria Blue B Agar” met GDAW (VBB-GDAW) teen verskillende temperature (25°C,
30°C, 37°C en 50°C). Indien donker-blou kolonies gevorm is of ‘n deursigbare sone
rondom ‘n kolonie waargeneem is, is lipolise as “positief” beskou. Lipolise is waargeneem
teen alle voorafgenoemde temperature vir P. fluorescens, P. luteola en S. maltophilia.
Bacillus licheniformis het nie lipolitiese aktiwiteit getoon teen 50°C op SBA-Tri. ‘n Afname
in die deursigbare sone is waargeneem teenoor ‘n toename in temperatuur vanaf 25°C tot
37°C vir P. fluorescens. In die geval van VBB-GDAW as lipiedsubstraat, het isolate geen
deursigbare sone vir lipolise getoon nie. Daar was egter ‘n donker-blou sone rondom
kolonies teenwoordig, wat ook positief is vir lipolitiese aktiwiteit.
Drie lipolitiese bakterieë (P. luteola, S. maltophilia, and B. licheniformis) is geïsoleer
uit bogenoemde studie en is aan inkubasie in GDAW teen verksillende VOGkonsentrasies
(70 – 211 mg.L-1) blootgestel. Hierdie isolate is toegelaat om te
akklimatiseer tot die GDAW tydens ‘n lot-bio-afbreekbaarheidstydperk (18 – 21 d) teen
37°C. Bacillus licheniformis het die hoogste VOG-afname van 83% na 18 d blootstelling
getoon. Alle bakterieë het getoon dat ‘n aanvanklike akklimatiserings-tydperk die bioafbreekbaarheid
van die VOG verbeter. ‘n Vetsuur-profiel is verkry vir elk van die lot-bio afbreekbaarheidstoetse na die akklimatiserings-fase. Daar is bevind dat hierdie bakterieë
óf die vetsure afgebreek het óf, soos in die geval van P. luteola, miristiese en
pentadesikliese sure, vanaf vry-vetsure, gevorm het. Die vorming van vetsure is moontlik
as gevolg van die proses van inter-esterifikasie. Dit is verder bevind dat sekere
voorlopers, soos palmitoë-oleïensuur, gevorm kan word onder aërobies of anaërobiese
toestande.
In hierdie studie is getoon dan die bio-afbreekbaarheid van VOG verbeter kan word
deur ‘n aanvanklike akklimatiserings-tydperk toe te pas. Enkel-kulture met die verkose
eienskappe kan gebruik word om die VOG in GDAW te verminder. Gemengde kulture,
wat inhiberende komponente produseer wat moontlik die bio-afbreekbaarheids proses
negatief kan beïnvloed, hoef dus nie gebruik te word nie. Bacillus licheniformis kan
gebruik word as ‘n VOG-afbrekende isolaat tydens die behandeling van afloopwater wat
hoog in VOG is. Verdere studies moet egter fokus op die samevoeging van VOGafbrekende
bakterieë vanuit hierdie studie asook ander bakterieë om die aktiwiteit daarvan
te monitor en sodoende oorlewing en aktiwteit op ‘n groter skaal te verseker.
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Degradation of textile wastewater using ultra-small Β-Feooh/Tio2 heterojunction structure as a visible light photocatalystNtiribinyange, Mary Solange January 2016 (has links)
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016. / The worldwide high demand for drinking water has led to the development of numerous
advanced wastewater treatment processes. Photocatalysis has recently become an alternative
and attractive technique for green energy production and environmental remediation. It is also
a wastewater treatment technique which is considered reliable and is expected to provide a
sustainable solution to the scarcity of clean water. In particular, heterogeneous photocatalysts
based on TiO2 nanoparticles and sunlight have been proposed as a powerful technique for
degradation and mineralisation of persistent organic pollutants (POP`s). Although this method
seems promising, some critical challenges are still to be addressed: namely, low photoefficiencies,
faster electron and hole (𝑒−⁄ℎ+) pair recombination, utilisation of UV light and
catalyst removal after treatment of pollutants.
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Biodegradation of diphenylamine and cis-dichloroetheneShin, Kwanghee 02 April 2010 (has links)
Past operational practices at chemical manufacturing facilities and widespread use of synthetic chemicals in agriculture, industry, and military operations have introduced many anthropogenic compounds to the biosphere. Some of them are readily biodegradable as a likely consequence of bacterial evolution of efficient degradation pathways, whereas others are partially degraded or persistent in the environment. Insight about biodegradation mechanisms and distribution of bacteria responsible provide the basis to predict the fate of synthetic chemicals in the environment and to enable bioremediation.
The main focus of the research described here encompasses basic science to discover pathways and evolutionary implications of aerobic biodegradation of two specific synthetic chemicals, cis-dichloroethene (cDCE) and diphenylamine (DPA). cDCE is a suspected carcinogen that frequently accumulates due to transformation of perchloroethene and trichloroethene at many contaminated sites. Polaromonas sp. strain JS666 is the only isolate able to use cDCE as the growth substrate, but the degradation mechanism was unknown. In this study, the degradation pathway of cDCE by strain JS666 and the genes involved were determined by using heterologous gene expression, inhibition studies, enzyme assays, and analysis of intermediates. The requirement of oxygen for cDCE degradation and inhibition of cDCE degradation by cytochrome P450 specific inhibitors suggested that cytochrome P450 monooxygenase catalyzes the initial steps of cDCE degradation. The finding was supported by the observation that an E. coli recombinant expressing cytochrome P450 monooxygenase catalyzes the transformation of cDCE to dichloroacetaldehyde and small amounts of the epoxide. Both the transient accumulation of dichloroacetaldehyde in cDCE degrading cultures and dichloroacetaldehyde dehydrogenase activities in cell extracts of JS666 further support a pathway involving the degradation of cDCE through dichloroacetaldehyde. Molecular phylogeny of the cytochrome P450 gene and organization of neighboring genes suggest that the cDCE degradation pathway evolved in a progenitor capable of degrading dichloroacetaldehyde by the recruitment of the cytochrome P450 monooxygenase gene from alkane assimilating bacteria. The discovery provides insight about the evolution of the aerobic cDCE biodegradation pathway and sets the stage for field applications.
DPA has been widely used as a precursor of dyes, pesticides, pharmaceuticals, and photographic chemicals and as a stabilizer for explosives, but little was known about the biodegradation of the compound. Therefore, bacteria able to use DPA as the growth substrate were isolated by selective enrichment from DPA-contaminated sediment and the degradation pathway and the genes that encode the enzymes were elucidated. Transposon mutagenesis, the sequence similarity of putative open reading frames to those of well characterized dioxygenases, and 18O2 experiments support the conclusion that the initial reaction in DPA degradation is catalyzed by a multi-component ring-hydroxylating dioxygenase. Aniline and catechol produced from the initial reaction of DPA degradation are then completely degraded via the common aniline degradation pathway. Molecular phylogeny and organization of the genes involved were investigated to provide insight about the evolution of DPA biodegradation.
The fate and transport of toxic chemicals are of a great concern at several historically contaminated sites where anoxic contaminant plumes emerge into water bodies. The release of toxic chemicals to overlying water poses a potential source of environmental exposure. Bench scale studies were conducted to evaluate the impact of biodegradation on the transport of toxic chemicals across the sediment/water interface. These studies demonstrated that substantial populations of bacteria associated with organic detritus at the interface rapidly biodegrade toxic chemicals as they migrate from contaminated sediment to overlying water, suggesting that the natural attenuation processes serve as a remedial strategy for contaminated sediments and protect the overlying water.
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Application of biogranules in the anaerobic treatment of distillery effluentsO'Kennedy, Onicha Deborah 12 1900 (has links)
Thesis (MSc Food Sc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The distillery industry produces large volumes of waste water with a high organic
content throughout the year. These effluents must be treated in some manner
before being discharged or recycled in the factory. Several treatment options are
in use presently, but they all have disadvantages of some nature, such as long
retention times, bad odours or the need for large areas of land. Considerable
interest has been shown in the application of anaerobic digestion, especially the
UASB design (upflow anaerobic sludge blanket), to treat this high strength waste
water. Thus, the aim of this study was to investigate the efficiency of an upflow
anaerobic sludge blanket (UASB) bioreactor using full-strength distillery effluent.
The activity of the bacteria in the biogranules was also evaluated by developing an
easy and reliable activity method to estimate the general biogas and
methanogenic activity and to calibrate this method using different anaerobic
granules from different sources.
The influence of high strength distillery effluent on the anaerobic digestion
process was investigated using a mesophilic lab-scale UASB bioreactor. During
the experimental study, the organic loading rate (OLR) was gradually increased
from 2.01 to 30.00 kgCOD.m-3.d-1, and simultaneously, the substrate pH was
gradually lowered from 7.0 to 4.7. It was found that at an OLR of 30.00 kgCOD.
m-3.d-1,the pH, alkalinity and biogas production stabilised to average values of 7.8,
6 000 mg.l-1 and 18.5 I.d-1 respectively. An average COD removal> 90% was
found indicating excellent bioreactor stability. The low substrate pH holds
considerable implications in terms of operational costs, as neutralisation of the
biorector substrate is no longer necessary. The accumulation of fine solids
present in the distillery substrate was found at the higher OLR's and resulted in the
granular bed increasing with subsequent biomass washout and a lowering in
efficiency parameters. However, a possible pre-treatment filtration of these fine
solids would eliminate this problem.
The success of the upflow anaerobic sludge bed (UASB) process is mainly
due to the capability of retaining the active biomass in the reactor. Over the years,
several methods have been developed to characterise and quantify sludge activity
but each has advantages and disadvantages. There is thus an increasing need for a rapid method to evaluate the activity of the granular biomass. The activity
method of Owen et al. (1979) as adapted by Lamb (1995), was thus evaluated in
terms of efficiency and applicability in determining the activity of granular samples.
The method was found to be inaccurate as well as time consuming and it was thus
modified. Results obtained with the modified assay method were found to be more
accurate and the impact of the different test substrates (glucose, lactate, acetate
and formate) on activity, was more evident. The activity of seven different
anaerobic granules, was subsequently evaluated. Biogas (Ss) and methanogenic
(SM) activity was not measured in volume of gas produced per unit COD converted
or volatile suspended solids (VSS), but as tempo of gas production (ml.h-1) in a
standardised basic growth medium. The activity data obtained were also
displayed as bar charts and "calibration scales". This illustrative depiction of
activity data gave valuable information about population dynamics as well as
possible substrate inhibition.
The "calibration scales" can also be used to group the general biogas (Ss)
and methanogenic activities (SM) of any new biogranule relative to active (O-type)
and inactive (W-type) anaerobic granules, providing that the same method of
activity testing is used. The "calibration scales" can thus be used to give a fast
indication of how the activity value of one sample relates to the activity values of
other granules, even when using different test substrates. / AFRIKAANSE OPSOMMING: Die stokery industrie produseer groot hoeveelhede afvalwater, wat hoë ladings van
organiese materiaal gedurede die hele jaar bevat. Hierdie afvalwater moet op een
of ander manier behandel word voordat dit gestort of vir hergebruik aangewend
kan word. Daar is tans verskeie behandelingsmetodes wat gebruik kan word, maar
elk het sy eie tekortkominge soos bv. lang retensie tye, onaangename reuke of
die behoefte aan groot stukke oop grond. Groot belangstelling is getoon vir die
gebruik van anaerobiese vertering, en meer spesifiek die "uflow anaerobic sludge
blanket" UASB bioreaktor vir die behandeling van stokery uitvloeisels. Die doel
van die studie was dus om die algehele effektiwiteit van 'n UASB bioreaktor, wat
onverdunde stokery uitvloeisel behandel, te evalueer. Die methanogene- en
algehele aktiwiteit van die bakterië in die biogranules was ook ge-evalueer deurdat
'n maklike en betroubare aktiwiteitsmetode omtwikkel is, waarna hierdie metode
ook toegepas was op 'n reeks van verskillende tipe biogranules.
Die invloed van volsterkte stokery uitvloeisel op die anaerobiese
verteringsprosesse was ondersoek met die gebruik van 'n mesofiele
laboratoriumskaal UASB bioreaktor. Gedurende die eksperimentele studie, was
die organiese ladingstempo (OLT) verhoog van 2.01 na 30.00 kgCSB.m-3.d-1
(CSB = chemiese suurstof behoefte) met die gelyktydige verlaging in die pH van
die bioreaktorsubstraat van 7.0 na 4.7. Dit was vasgestel dat met 'n OLT van
30.00 kgCSB.m-3.d-1, die pH, alkaliniteit en biogas geproduseer, gestabiliseer het
na gemiddelde waardes van 7.8, 6000 mg.-1 en 18.5l.d-1
, respektiewelik, sowel
as 'n gemiddelde CSB verwydering van> 90%. Al hierdie waardes dui uitstekende
bioreaktor stabiliteit aan. Die lae bioreaktorsubstraat pH kan van groot waarde
wees vir die industrie, aangesien neutralisering van die uitvloeisel nie meer nodig
is nie en kan sodoende die operasionele koste van die proses verlaag. Die
konsentrering van fyn opgeloste soliedes in die bioreaktor by hoë OLT's, kan egter
problematies raak, aangesien dit die granule-bed kan vergroot en veroorsaak dat
van die biomassa uitspoel en kan verlore gaan. Die verlies van aktiewe biomassa
kan die effektiwiteitsparameters negatief beinvloed, maar die plasing van 'n
filterings stap voor die verterings stap, behoort hierdie probleem op te los. The sukses van die UASB-stelsel rus op die versekering dat die aktiewe
biomassa in die reaktor behoue bly. Oor die jare was daar 'n verskeidenheid van
aktiwiteitstoetsings-metodes ontwikkel, elk met sy eie nadele. Daar bestaan dus
nog steeds 'n groot behoefte vir die daarstelling van 'n aktiwiteitstoetsings-metode
wat vinnig en maklik is om uittevoer. Die aktiwiteitstoetsings-metode van Owen et
al. (1979) wat deur Lamb (1995) aangepas is, was in terme van sy effektiwiteit en
toepaslikheid ten opsigte van die gebruik daarvan vir aktiwiteitstoetsing vir
biogranules, ge-evalueer. Dit is bevind dat die metode onakkuraat sowel as
tydsrowend was en gevolglik dus aangepas. Die aangepaste metode het meer
akkurate resultate gelewer en die impak van die verskillende toetssubstrate
(glukose, laktaat, asetaat en formaat) op die granules het ook meer duidelik na
vore gekom. Gevolglik was die aktiwiteit van sewe verskillende anaerobiese
biogranules ondersoek. Die eenheid waarin atiwiteitsresultate aangegee is, was
nie in volume gas geproduseer per eenheid CSB verwyder of per hoeveelheid
gesuspendeerde vlugtige vetsure in die biomassa nie, maar as tempo van biogas
(S8)- of metaan (SM)produksie (ml.h-1). Die data wat op hierdie wyse bekom was,
is gebruik om staafdiagramme sowel as "kalibrasie skale" daar te stel. Hierdie
illustrerende wyse om aktiwiteitsdata uit te beeld verskaf waardevolle informasie
ten opsigte van die interaksies tussen die verskillende populasies in die granule en
kan ook die aanwesigheid van moontlike substraat inhibisie aandui. Die
"Kalibrasie skale" kan ook gebruik word om die algehele (SB) en methanogene
(SM)aktiwiteite van einge nuwe biogranule vinnig te klassifiseer ten op sigte van 'n
aktiewe (O-tipe) en 'n minder aktiewe (W-tipe) anaerobiese granules, mits
dieselfde metode gebruik word om die aktiwiteits data te bekom.
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