The overall efficiency of plants to remediate soils contaminated by metals depends on their growth ability especially on soils with low-fertility. For twelve weeks, the ability of Psoralea pinnata to grow well and remove chromium and iron from artificially contaminated soil was tested. The concentrations of chromium and iron in two soils obtained from different sources namely, University of South Africa premises (US) and commercial potting soil (PS) were 80 ppm, 130ppm, 180ppm, 230ppm, 280ppm, 330ppm, 380pp, 430ppm and 480ppm. Psoralea pinnata was transplanted into the contaminated soils and the experiments were watered daily to maintain 70% moisture at field capacity in a greenhouse. Shoot height and root length of Psoralea pinnata before and after planting were measured. Other parameters that were measured were number of leaves, wet shoot and dry weights, and wet root and dry weights. The growth of Psoralea pinnata, after 12 weeks of experimentation was noticeably affected by the concentrations of chromium and iron in the soil. The percentage increases in shoot height of Psoralea pinnata in the PS Soil (C-PS, 48cm from initial shoot height of 12.6cm) treatments were generally higher than the increases in the US Soil (C-US, 45.2cm from initial shoot height of 12.8cm) treatments. Psoralea pinnata in the (US) treatments accumulated Fe (50.02 ppm) from the soil more than Cr (32.38ppm). In the (PS) treatments, Psoralea pinnata also accumulated more Fe (60.57 ppm) than Cr (38.34 ppm). In the experiments containing both Fe and Cr, the US treatments with 40 ppm each of Cr and Fe, chromium was initially mostly accumulated by Psoralea pinnata (68%). At higher concentrations (320 ppm) of the combined metals (Cr and Fe) treatment, more Fe (55%) was accumulated in Psoralea pinnata. This study however showed that Psoralea pinnata may not be an efficient phytoextraction plant for hyperaccumulation. / Environmental Sciences / M. Sc. (Environmental Management)

Introduction Run-off from Johannesburg mine dumps is a source of environmental pollution and a public health concern. This study focussed on assessing and developing remediation strategies for Manuel Street Park (MSP) that has been affected by run-off from the Princess Mine dump. Study objectives were threefold: to use a survey involving residents living around MSP to determine community use and perception of rehabilitation of the Park; to determine the impact of the addition of a preparation known as “Effective Micro-organisms” (EM®) to polluted Park soil and; to prepare a remediation plan for this Park. Methodology A qualitative survey was conducted amongst users of the park as to their use and perceptions of rehabilitation of the park and their understanding of mine-related pollution and acid mine drainage. Controlled greenhouse trials were conducted to determine optimal germination and growth of Pennisetum clandestinum (Kikuyu grass) in Park soil, with and without EM® or compost. A landscaper was consulted to collate research results to facilitate park rehabilitation. Results Survey participants understood the risks of Acid Mine Drainage (AMD) and other mine pollution and gave valuable information which assisted in understanding local issues concerning the park. Tests with soil polluted with AMD showed that it promoted seed germination while treatment of park soil with fertiliser, compost and enhanced microorganisms improved plant development and growth. Practically, it was determined that the use of EM1 at the park would be difficult because of on-going flooding of the park with contaminated water. For this reason, an improved drainage plan was suggested, along with raised walkways. Conclusion A remediation plan can be implemented on site involving installation of French drains, raised walkways, and soil remediation involving EM® / Agriculture, Animal Health and Human Ecology / M. Sc. (Environmental Management Ornamental Horticulture)

Thesis (MSc (Conservation Ecology)--University of Stellenbosch, 2004. / 89 leaves single sided printed, preliminary pages i-xiv and numbered pages 1-89. Includes bibliography. List of tables, figures used. / Scanned with a Hp Scanjet 8250 Scanner to pdf format (OCR). / ENGLISH ABSTRACT: The main aim of an old field rehabilitation trial initiated in 2000 was to find a solution to the rehabilitation process for approximately 90 000 ha of unutilised land in the Little Karoo, South Africa. Depending only on a natural succession process to restore unutilised old fields would mean that the period of recovery would be longer than the life span of an average farmer. The trial, initiated by Witbooi in 2000 aimed to see how human intervention can facilitate the process of rehabilitation of old-fields. Three years later, the trial was again monitored to evaluate the success of reseeded indigenous species and method of cultivation in the rehabilitation process. A second objective was based on a result of Witbooi (2002) who showed that there was a tendency of 0. pes-caprae to invade disturbed areas, and aimed to evaluate the effect of this species on the rehabilitation process. Seven indigenous species were reseeded in 2000, of which only four species germinated and survived to the present. These surviving species are Pteronia incana Burm Dc., Tripteris sinuata DC., Ehrharta calycina SM and Chaetobromus dregeanus Nees. The highest level of recruitment in 2001 was recorded for T sinuata followed by P. incana, E. calycina and C. dregeanus. In September 2003, three years after the trial was initiated, the highest number of surviving seedlings were of T sinuata followed by E. calycina, C. dregeanus and P. incana. Five different cultivation methods were used to enhance the germination rate and survival of seedlings. The number of seedlings that survived differs according to the cultivation methods and soil type. Tripteris sinuata had the highest number of surviving seedlings in all cultivation methods off-heuweltjies. Tripteris sinuata was therefore selected to analyse the effect of various cultivation methods. The second objective was to study the impact of Oxalis pes-caprae on species diversity in restored old fields by assessing its ability to disperse in old fields under different cultivation methods. The multivariate ANOVA results showed that there was a significant difference in the density of O. pes-caprae between on and off heuweltjies (sites) and treatments (cultivation methods). There was a significant difference in the density of O. pes-caprae between cultivation methods. A Post Hoc LSD test showed a significant difference in the density of aboveground O. pes-caprae plants between control sites (no disturbance) compared to those sites that underwent some sort of soil disturbance. There was, however, no significant difference in the abundance of O. pes-caprae on plots that underwent some sort of disturbance (i.e Cleared vs Tilled vs Disked vs Ploughed sites) on heuweltjies. There was a significant difference in the number of O. pes-caprae bulbs collected between blocks (on and off-heuweltjie) and significant differences between cultivation methods. There was also a significant difference in bulb diameter between cultivation methods when compared between on and off-heuweltjie sites. The bulbs were classified into four measurement classes. The highest number of small (2-5 mm diameter) and medium (5-8 mm diameter) sized bulbs were found in the Tilled cultivation method. In contrast the Control treatment (uncultivated) had the highest number of large sized bulbs (14-17 mm diameter) and medium bulbs size categories. In conclusion, T. sinuafa has the potential to be used for rehabilitation of old fields in combination with Tilled cultivation method. Attention should be paid to the effect of O. pes-caprae especially on heuweltjies where this species showed a complete dominance in the rehabilitation trial. / AFRIKAANSE OPSOMMING: Die hoof doel van 'n ou veld rehabilitasie eksperiment wat in 2000 geinisieer is was om 'n oplossing te vind vir die rehabilitasie proses vir ongeveer 90 000 ha onbenutte land in die Klein Karoo, Suid-Afrika. Indien daar slegs op natuurlike suksessie prosesse staatgemaak word om die onbenutte ou lande te restoreer, sou dit beteken dat die periode van herstel langer sou wees as die lewensverwagting van die gemiddelde boer. Hierdie eksperiment, wat in 2000 deur Witbooi geinisieer is, het gepoog om te bepaal hoe menslike inmenging die proses van rehabilitasie van ou velde kan fasiliteer. Drie jaar later is die eksperiment weer gemonitor om die sukses van die teruggesaaide inheemse spesies en bewerkings-metodes in die rehabilitasie proses te evalueer. 'n Tweede doelwit is gebaseer op 'n resultaat van Witbooi (2002) wat aangetoon het dat daar 'n neiging was vir O. pes-caprae om versteurde areas binne te dring, en het dus gemik om die effek van hierdie spesie op die rehabilitasie proses te evalueer. Sewe inheemse spesies is in 2000 teruggesaai, waarvan slegs 4 spesies ontkiem en oorleef het tot die hede. Hierdie oorlewende spesies is Pteronia incana Burm Dc., Tripteris sinuata DC., Ehrharta calycina SM en Chaetobromus dregeanus Nees. Die hoogste vlak van werwing in 2001 is vir T sinuata aangeteken, gevolg deur P. incana, E. calycina en C. dregeanus. In September 2003, drie jaar na die aanvang van die eksperiment, was die hoogste getal oorlewende saailinge die van T sinuata, gevolg deur E. calycina, C. dregeanus en P. incana. Vyf verskillende bewerkings-metodes is gebruik om ontkiemingstempo en saailing oorlewing aan te help. Die aantal saailinge wat oorleef het varieer volgens die bewerkings-metode wat gevolge is en die grondtipe. Tripteris sinuata het die grootste aantal oorlewende saailinge gehad in al die bewerkings-metodes af van heuweltjies. Tripteris sinuata is daarom geselekteer om te analiseer vir die effek van verskillende bewerkings-metodes. Die tweede doelwit was om die inpak van Oxalis pes-caprae op spesie-diversiteit in die gerestoreerde ou land te bepaal deur die vermoë van hierdie spesie om in ou velde te versprei onder verskillende bewerkings-metodes te evalueer. Die multi-veranderlike ANOVA resultate het aangetoon dat daar 'n beduidende verskil in O. pes-caprae digtheid tussen heuweltjie en nie-heuweltjie (persele) en verskillende bewerkings-metodes was. Daar was 'n beduidende verskil in die digtheid van o. pes-caprae tussen verskillende bewerkingsmetodes. 'n Post Hoc LSD toets het 'n beduidende verkil in die digtheid van bogrondse O. pes-caprae plante tussen kontrole terreine (geen versteuring) vergeleke met persele wat een of ander vorm van grondversteuring ondergaan het aangedui. Daar was egter geen beduidende verskil in die volopheid van 0. pes-caprae op persele wat een of ander vorm van versteuring ondergaan het (i.e Skoongemaakte vs Getilde vs Geskottelde vs Geploegde persele) op heuweltjies nie. Daar was 'n beduidende verskil in die aantal O. pes-caprae bolle wat versamel is tussen blokke (op en af van heuweltjies) en beduidende verskille tussen die bewerkings-metodes. Daar was ook 'n beduidende verskil in bol-deursnitte tussen bewerkings-metodes wanneer dit tussen heuweltjie en nie-heuweltjie persele vergelyk is. Die bolle is in vier metingsklasse verdeel. Die grootste aantal klein (2-5 mm deursnit) en medium (5-8 mm deursnit) bolle is in die Getilde bewerkings-metode gevind. In kontras het die Kontrole behandeling (onbewerk) die grootste aantal groot (14-17 mm deursnit) en medium bolle gehad. Samevattend het T. sinuata die potensiaal om gebruik te word in die rehabilitasie van ou lande in kombinasie met die tilting bewerkings-metode. Aandag moet geskenk word aan die effek van 0. pes-caprae, veral op heuwetjies waar hierdie spesies 'n totale dominansie in die rehabilitasie eksperiment getoon het.

by Ho, Kai-Man. / Thesis submitted in: December 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 158-179). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstracts --- p.ii / Contents --- p.vii / List of figures --- p.xiv / List of tables --- p.xvii / Abbreviations --- p.xx / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Poly cyclic Aromatic Hydrocarbons (PAHs) / Chapter 1.1.1 --- Characteristics of PAHs --- p.1 / Chapter 1.1.2 --- Sources of PAHs --- p.3 / Chapter 1.1.3 --- Environmental fates of PAHs --- p.5 / Chapter 1.1.4 --- Effects of PAHs on living organisms --- p.7 / Chapter 1.1.5 --- Summary --- p.10 / Chapter 1.2 --- Target PAH: Benzo[a]pyrene (BaP) --- p.10 / Chapter 1.3 --- PAH contamination in Hong Kong --- p.14 / Chapter 1.4 --- Remediation for PAHs contaminated soils --- p.15 / Chapter 1.4.1 --- Chemical/ Physical methods --- p.15 / Chapter 1.4.2 --- Bioremediation --- p.16 / Chapter 1.5 --- Biodegradation of PAHs by bacteria and fungi --- p.18 / Chapter 1.5.1 --- Tolerance and degradation --- p.18 / Chapter 1.5.2 --- Biodegradation of PAHs by microorganisms --- p.20 / Chapter 1.5.2.1 --- Bacteria --- p.22 / Chapter 1.5.2.2 --- Fungi --- p.23 / Chapter 1.6 --- Environmental standards --- p.26 / Chapter 1.7 --- Strategies of soil sampling and microbial isolation --- p.26 / Chapter 1.7.1 --- Contaminated soil vs. uncontaminated soil --- p.26 / Chapter 1.7.2 --- Native species vs. foreign species --- p.29 / Chapter 1.7.3 --- Background of the sampling areas --- p.30 / Chapter 1.7.3.1 --- North Tsing Yi shipyard --- p.30 / Chapter 1.7.3.2 --- "Tsam Chuk Wan, Sai Kung" --- p.33 / Chapter 1.8 --- Objectives of this study --- p.33 / Chapter 2. --- Materials and Methods --- p.35 / Chapter 2.1 --- Soil Collection --- p.35 / Chapter 2.1.1 --- Abandoned shipyard soil and its sediment soil --- p.35 / Chapter 2.1.2 --- "Tsam Chuk Wan, Sai Kung" --- p.35 / Chapter 2.2 --- Characterization of soils --- p.35 / Chapter 2.2.1 --- Sample preparation --- p.36 / Chapter 2.2.2 --- Soil pH --- p.36 / Chapter 2.2.3 --- Electrical conductivity --- p.36 / Chapter 2.2.4 --- Salinity --- p.36 / Chapter 2.2.5 --- Total organic carbon contents --- p.38 / Chapter 2.2.6 --- Metal analys --- p.is / Chapter 2.2.7. --- Oil and grease content --- p.38 / Chapter 2.2.8 --- Soil texture --- p.39 / Chapter 2.2.9 --- Available ammoniacal nitrogen and oxidized nitrogen --- p.39 / Chapter 2.2.10 --- Available Phosporus --- p.40 / Chapter 2.2.11 --- Total Nitrogen and total Phosporus --- p.40 / Chapter 2.2.12 --- Moisture / Chapter 2.2.13 --- DTPA-extractable metals --- p.41 / Chapter 2.2.14 --- Extraction of PAHs and organic pollutants --- p.41 / Chapter 2.2.14.1 --- Extraction procedures --- p.41 / Chapter 2.2.14.2 --- GC-MSD conditions --- p.41 / Chapter 2.2.14.3 --- Extraction efficiency --- p.43 / Chapter 2.2.15 --- Soil colour --- p.43 / Chapter 2.3 --- Screening and selection of microorganismms --- p.43 / Chapter 2.3.1 --- Isolation of potential BaP-degrading microorganisms --- p.44 / Chapter 2.3.1.1 --- Isolation of bacteria --- p.44 / Chapter 2.3.1.2 --- Isolation of fungi --- p.44 / Chapter 2.3.2 --- Cultures preserving microorganisms --- p.46 / Chapter 2.3.3 --- Screening and selection of microbes --- p.46 / Chapter 2.3.3.1 --- Bacteria --- p.46 / Chapter 2.3.3.2 --- Fungi --- p.46 / Chapter 2.3.4 --- Survival test --- p.47 / Chapter 2.3.5 --- Removal efficiency (RE) towards BaP by the microorganisms --- p.47 / Chapter 2.3.5.1 --- Bacteria --- p.47 / Chapter 2.3.5.2 --- Fungi --- p.48 / Chapter 2.3.6 --- Removal efficiency (RE) --- p.48 / Chapter 2.3.7 --- Relationship of absorbance of bacterial culture and bacterial biomass --- p.49 / Chapter 2.4 --- Identification of selected microorganisms --- p.49 / Chapter 2.4.1 --- Identification of bacterium --- p.49 / Chapter 2.4.1.1 --- 16S rDNA sequencing --- p.49 / Chapter 2.4.1.1.1 --- Primers --- p.49 / Chapter 2.4.1.1.2 --- DNA extraction --- p.51 / Chapter 2.4.1.1.3 --- Specific PCR --- p.51 / Chapter 2.4.1.1.4 --- Gel electrophoresis --- p.51 / Chapter 2.4.1.1.5 --- Purification of PCR products --- p.52 / Chapter 2.4.1.1.6 --- DNA sequencing --- p.52 / Chapter 2.4.1.2 --- Midi Sherlock® Microbial Identification System (MIDI) --- p.53 / Chapter 2.4.1.3 --- Biolog MicroLog´ёØ system (Biolog) --- p.55 / Chapter 2.4.2 --- Identification of fungi --- p.56 / Chapter 2.4.2.1 --- ITS DNA sequencing --- p.56 / Chapter 2.4.2.2 --- Observation under electronic microscope --- p.58 / Chapter 2.5 --- Growth curve of the microorganism --- p.58 / Chapter 2.5.1 --- Bacterium --- p.58 / Chapter 2.5.2 --- Fungi --- p.58 / Chapter 2.6 --- Preparation of Benzo[a]pyrene (BaP) stock solution --- p.58 / Chapter 2.7 --- Comparison of isolated bacterium and fungi --- p.60 / Chapter 2.8 --- Optimization of BaP degradation by selected fungus --- p.60 / Chapter 2.8.1 --- Preparation of straw compost inoculated with selected fungus --- p.60 / Chapter 2.8.2 --- Effect of incubation time --- p.61 / Chapter 2.8.3 --- Effect of initial BaP concentration --- p.61 / Chapter 2.8.4 --- Effect of inoculum size / Chapter 2.8.5 --- Effect of temperature --- p.61 / Chapter 2.8.6 --- Effect of soil pH --- p.62 / Chapter 2.8.7 --- Study of BaP degradation pathway by the microorganisms using GC-MSD --- p.62 / Chapter 2.9 --- Chitin Assay --- p.62 / Chapter 2.10 --- Enzyme assay --- p.63 / Chapter 2.10.1 --- Laccase assay --- p.63 / Chapter 2.10.2 --- Manganese peroxidase assay --- p.63 / Chapter 2.10.3 --- Lignin peroxidase assay --- p.64 / Chapter 2.11 --- Toxicity of treated soil --- p.64 / Chapter 2.12 --- Statistical analysis --- p.65 / Chapter 3. --- Results --- p.66 / Chapter 3.1 --- Soil Collection --- p.66 / Chapter 3.1.1 --- North Tsing Yi shipyard --- p.66 / Chapter 3.1.2 --- "Tsam Chuk Wan, Sai Kung" --- p.66 / Chapter 3.2 --- Characterization of soil samples --- p.71 / Chapter 3.3 --- Extraction efficiency of Benzo[a]pyrene --- p.79 / Chapter 3.4 --- Screening and selection of microorganisms --- p.79 / Chapter 3.4.1 --- Isolation ofpotential BaP-degrading microorganisms --- p.79 / Chapter 3.4.2 --- Screening and selection of microbes --- p.87 / Chapter 3.4.2.1 --- Bacteria --- p.87 / Chapter 3.4.2.2 --- Fungi --- p.93 / Chapter 3.4.3 --- Growth curve of the microorganisms --- p.95 / Chapter 3.4.3.1 --- Bacterium --- p.95 / Chapter 3.4.3.2 --- Fungi --- p.99 / Chapter 3.5 --- Comparison of isolated bacterium and fungi --- p.99 / Chapter 3.6 --- Identification of selected microorganisms --- p.102 / Chapter 3.6.1 --- Identification of bacterium --- p.103 / Chapter 3.6.1.1 --- 16S rDNA sequencing --- p.103 / Chapter 3.6.1.2 --- Midi Sherlock® Microbial Identification System (MIDI) --- p.103 / Chapter 3.6.1.3 --- Biolog MicroLog´ёØ system (Biolog) --- p.107 / Chapter 3.6.2 --- Identification of fungi --- p.107 / Chapter 3.6.2.1 --- ITS DNA sequencing --- p.107 / Chapter 3.6.2.2 --- Observation under electronic microscope --- p.113 / Chapter 3.7 --- Optimization of BaP degradation by the selected fungus: Trichoderma asperellum --- p.107 / Chapter 3.7.1 --- Effect of incubation time --- p.107 / Chapter 3.7.2 --- Effect of inoculum size --- p.113 / Chapter 3.7.3 --- Effect of initial BaP concentration --- p.113 / Chapter 3.7.4 --- Effect of soil pH --- p.113 / Chapter 3.7.5 --- Effect of temperature --- p.117 / Chapter 3.8 --- Determination of breakdown products of BaP by BaP-degrading microorganisms --- p.117 / Chapter 3.9 --- Enzyme assay --- p.117 / Chapter 3.10 --- Evaluation of toxicity by using indigenous bacteria --- p.121 / Chapter 4. --- Discussion --- p.128 / Chapter 4.1 --- Physico-chemical properties of soil samples --- p.128 / Chapter 4.2 --- Determination of BaP and other organic compounds --- p.131 / Chapter 4.3 --- Identification of the microorganisms --- p.132 / Chapter 4.3.1 --- Bacteria --- p.132 / Chapter 4.3.2 --- Fungi --- p.134 / Chapter 4.4 --- Biodegradation by BaP-degrading microorganisms --- p.135 / Chapter 4.4.1 --- Isolation and screening of BaP-degrading microorganisms --- p.135 / Chapter 4.4.2 --- Biodegradation of BaP --- p.137 / Chapter 4.4.2.1 --- Bacteria --- p.137 / Chapter 4.4.2.2 --- Fungi --- p.138 / Chapter 4.4.3 --- BaP degradation pathway --- p.140 / Chapter 4.4.3.1 --- Bacteria --- p.140 / Chapter 4.4.3.2 --- Fungi --- p.140 / Chapter 4.5 --- Optimization of PAH degradation by T. asperellum --- p.143 / Chapter 4.5.1 --- Effect of incubation time --- p.143 / Chapter 4.5.2 --- Effect of initial BaP concentration --- p.144 / Chapter 4.5.3 --- Effect of inoculum size fungus --- p.144 / Chapter 4.5.4 --- Effect of soil pH --- p.145 / Chapter 4.5.5 --- Effect of temperature --- p.146 / Chapter 4.6 --- Comparison the selected bacterium and fungi --- p.146 / Chapter 4.7 --- Evaluation of toxicity by using in indigenous bacteria --- p.148 / Chapter 4.8 --- Post treatment by crude enzyme of Pleurotus pulmonarius --- p.149 / Chapter 4.9 --- Limiting factors for BaP degradation --- p.150 / Chapter 4.10 --- Further Investigations --- p.152 / Chapter 5. --- Conclusion --- p.155 / Chapter 6. --- References --- p.158

Les zones sources formées par les organochlorés dans les sols (DNAPL) peuvent contaminer les aquifères pour plusieurs siècles en alimentant un panache de composés dissous. Pour épuiser ces zones sources, pomper le DNAPL est la solution la plus simple, mais l’efficacité est limitée par le cheminement préférentiel de l'eau dans le sol et les forces capillaires qui piègent le DNAPL. Les stratégies plus agressives (dissolution, traitement thermique, dégradation chimique…) sont aussi plus coûteuses. Dans cette thèse, deux stratégies de traitement à base de mousse de surfactant ont été développées et évaluées au laboratoire en préparation d’un essai terrain. La première stratégie utilise l’injection de mousse en zone source pour mobiliser de façon contrôlée le DNAPL et le diriger vers des puits de pompage. Dans les meilleures conditions, la saturation en DNAPL après traitement a pu être abaissé en dessous de 1 % avec une consommation de surfactant inférieure à 10 g kg-1 de DNAPL éliminé. La seconde stratégie utilise la mousse comme vecteur de réactif (hydrogène) pour accélérer la biodégradation des composés dissous dans le panache. Sous forme de mousse, l’hydrogène a été délivré de façon ciblée et plus rémanente dans l’horizon à traiter. Les technologies développées se sont montrées très prometteuses à l’échelle du terrain et lors de l’évaluation technico-économique. De la recherche reste nécessaire pour rendre ces procédés plus prédictibles lors de leur mise en œuvre. / Source zones formed by chlorinated organic compounds in soils (DNAPL) can contaminate aquifers for several centuries by feeding a plume of dissolved compounds. To deplete those source zones, DNAPL pumping is the simplest option, but the efficacy is limited by preferential water flow in the soil and capillary forces that are trapping the DNAPL. More aggressive strategies (dissolution, thermal treatment, chemical degradation...) are also costlier. Within this thesis work, two treatment strategies using surfactant foam were developed and assessed at lab-scale to prepare field assessment. The first strategy relies on foam injection in the source zone to mobilize the DNAPL in a controlled fashion to drive it ahead to pumping wells. In the best conditions, DNAPL saturation was lowered below 1% after treatment with a surfactant consumption below 10 g kg-1 of DNAPL removed. The second strategy uses foam as a reagent (hydrogen) carrier to accelerate the biodegradation of dissolved compounds in the plume. When injected as a foam, hydrogen was delivered in a targeted and more persistent manner in the strata to be treated. Developed technologies showed to be promising at field-scale and when the technico-economic assessment was conducted. Research still remains to be done to make those techniques more predictable during their implementation.

Thesis (MSc. Agriculture (Soil Science)) -- University of Limpopo, 2019 / Global shortage of fresh quality water has led to the use of treated wastewater in arid and semi-arid regions. Although, the treated wastewater has proven to be the best solution in ameliorating pressures brought by water shortage, it contains toxic heavy metals, some in high concentrations that could possibly pose health risks and degrade soil quality. Therefore, the objectives of the study were to determine the vertical and horizontal distribution of bioavailable heavy metals on virgin, cultivated and fallowed fields and to investigate the bioremediation abilities of selected soil microbes on non-essential heavy metals in cultivated and fallowed soils following irrigation with treated wastewater at University of Limpopo (UL) Experimental Farm. Three fields, namely, virgin field (VF), cultivated field (CF) and fallowed field (FF), each being 6.4 ha, were each divided into 40 equal grids, equivalent to 40 m × 40 m, which were used in vertical assessment of heavy metals. Soil profiles were established inside each grid and soil samples collected at 0-20; 20-40 and 40-60 cm soil depth for further laboratory analysis. The soil samples were analyzed for basic soil physico-chemicals, namely, particle size distribution, soil pH (H20 and KCl), electrical conductivity (EC), reduction potential (Eh), organic carbon (OC) and cation exchange capacity (CEC). Five essential heavy metals namely zinc (Zn), iron (Fe), copper (Cu), cobalt (Co), manganese (Mn) and five non-essential heavy metals, namely, arsenic (As), chromium (Cr), lead (Pb), aluminium (Al), and cadmium (Cd), were also extracted from the soil samples. Heavy metal resistant Gram-negative (–) and Gram-positive (+) bacteria were isolated from the soil and identified as Providencia rettgeri (–), Enterobacter cloacae (–), Bacillus cereus (+) and Arthrobacter aurescens (+). xix The isolated bacteria were cultured and inoculated in heavy metal-contaminated soils and incubated for 12 weeks to bioremediate the non-essential heavy metals. Results obtained suggested that the treatments had no significant (P ≤ 0.05) effects on vertical distribution of all the essential and non-essential heavy metals among the three fields. However, on average Co was above the permissible level at 53 mg/kg in CF at 0-20 cm and although all the other essential heavy metals increased, they were still within the permissible levels. The concentration of As was also above the permissible levels in CF with an average concentration of 4.30 mg/kg. Cadmium levels were also above the permissible levels in CF with an average concentration of 1.146 mg/kg in CF and this increased by 0.46 units from VF which had an average value of 1 mg/kg. However, fallowing reduced Cd to 0.51 mg/kg which was below or within the expected limits in soil previously irrigated with treated waste water. Gram-positive bacteria reduced more concentrations of non-essential heavy metals separately and combined, especially in the fallowed field. Irrigation with treated wastewater has shown to have both negative and positive effects on the concentration of essential and non-essential heavy metals in cultivated and fallowed fields. Bioremediation coupled with fallowing has been proven to be the best solution in ameliorating heavy metal toxicity while naturally improving the quality of the soil. / National Research Foundation (NRF)

Die elektrokinetische Bodensanierung nutzt Transporteffekte aus, die entstehen, wenn ein elektrisches Feld an einen Bodenkörper angelegt wird. Die Sanierungsmethode versagt bei immobilen Schadstoffen. Allerdings scheint unter bestimmten Bedingungen ein im Boden induzierter Abbau der Schadstoffe möglich. Dafür müssen so genannte "Mikroleiter" und Redox-Systeme im Boden vorhanden sein. Hierzu werden theoretische Modelle vorgestellt. An einem konkreten Beispiel (mit aliphatischen Chlorkohlenwasserstoffen kontaminierter Boden) wurde getestet, ob direkt im Boden ein Abbau der Schadstoffe mit der Technik der elektrochemischen Bodensanierung erzielt werden kann. Die Analyse der CKW wurde per GC-MS durchgeführt. Theoretisch ist ein reduktiver Abbau oder eine Dechlorierung durch Eliminierungsreaktionen möglich. Die Ergebnisse der Laborversuche (Einwaage 100-3.000 g) erbrachten unter Einhaltung bestimmter Faktoren einen erfolgreichen Abbau der CKW. Bei ständiger Bewässerung des Bodens und einer Feldstärke von mindestens 600 V/m konnte ein Abbau festgestellt werden. Die Erhöhung des Chlorid-Gehaltes im Abwasser zeigt die erfolgreiche Abbaureaktion an. Potentielle Abbauprodukte mit weniger Chlor-Atomen im Molekülaufbau konnten nachgewiesen werden. Diese Stoffe lassen sich mit den ursprünglichen Kontaminationssubstanzen verknüpfen. Da eine Migration der Schadstoffe im elektrischen Feld nicht beobachtet wurde, wird eine im Boden induzierte Abbaureaktion angenommen. In Bodenzonen mit hohem pH-Wert (Eliminierung) und in Kathodennähe (Reduktion) waren die stärksten Abbauraten zu verzeichnen. Bei Versuchen ohne ständige Bewässerung war der CKW-Abbau schwach. Die Widerstände stiegen stark an. Ein Versuch in einem Container (Einwaage Boden: ca. 2 t) erbrachte nur einen punktuellen Abbau der CKW. Die Struktur des Originalbodens verhinderte den Aufbau eines homogenen elektrischen Feldes. In einem Fassversuch (Einwaage Boden: ca. 33 kg) wurden die Versuchsbedingungen modifiziert. Anlagerungen an allen Elektroden verhinderten eine ausreichend hohe effektive Feldstärke im Bodenkörper. Sanierungseffekte fanden nur lokal begrenzt statt. Im Vergleich von Labor zu Großversuchen zeigte sich, dass die eingetragene Ladungsmenge eine entscheidende Rolle spielt.

Syfte: Rödfyr är gruvavfall från förbränning av alunskiffer. Materialet finns i naturen på många platser i Västra Götaland. Fram till 80-talet användes rödfyren som utfyllnadsmaterial men numera är användningen begränsad då materialet lakar tungmetaller. Mängden avfall som går till deponi skall minskas. Möjligheten att deponera rödfyrsmassor är därmed begränsad då områden med rödfyrshögar skall bebyggas. Syftet med denna studie är därför att öka kunskapen om hur rödfyrsmassor kan hanteras på ett miljömässigt och ekonomiskt sätt. Målet är att ge förslag på användningsområden och hanteringsmetoder för rödfyrsmassor för att bidra till bättre miljö och ekonomiska och förutsättningar. Genom att utreda vilka krav som ställs på användning av rödfyr, söktes svar på möjliga användningsområden och konstruktionslösningar för att minska lakningen. Denna studie är ett examensarbete som genomförts i samarbete med Skövde kommun. Metod: Valda metoder för datainsamling är litteraturstudie, dokumentanalys samt semi-strukturerade intervjuer. I litteraturstudien studerades litteratur om avfall, rödfyr, och efterbehandlingsmetoder. I dokumentanalysen studerades miljöutredningar för rödfyr för att erhålla kunskap om lakningen. Intervjuerna gav information om tillståndsmyndigheternas arbete med rödfyr, och sakkunnigas förslag på hur rödfyr bör användas och hanteras. Resultat: Studien visade att det finns andra användningsområden än deponi, samt att det finns metoder för att begränsa rödfyrens lakning. Det måste finnas kunskaper om hur rödfyrens spridning sker vid omröring och flytt. Att förhindra lakning kan uppnås genom att kapsla in rödfyren med hjälp av olika tätskikt. Detta innebär att rödfyren kan nyttjas som en resurs, ytor blir tillgängliga för exploatering, samt att rödfyren inte är tillgänglig för människor, och att lakningen till grundvattnet minskas. Konsekvenser: Rödfyr kan användas som utfyllnadsmaterial vid mindre känslig markanvändning, såsom industriområden och vägar. Detta är under förutsättning att övertäckning av massorna sker för att undvika lakning. Asfaltsytor, i kombination med ett tätskikt på ovansida, samt vertikala sidor, begränsar lakningen avsevärt. Överytan kan då utnyttjas för exploatering. Transportsträckan är ofta ekonomiskt avgörande för om rödfyren kan flyttas eller inte. Om rödfyren kan nyttjas för utfyllnadsändamål minskar kostnaden för inköp av material, och nya uttag av massor belastar inte miljön. Begränsningar: Den rödfyr som studerats är den som finns i Skövde Kommun. Studien bör dock kunna tillämpas på övriga länet. En begränsning är att intervjustudien inte genomfördes så omfattande. Ytterligare hade genomförande av skaktester i studien kunnat bidra med kunskap. På grund av den tid som krävs för detta var det ej möjligt. Dock erhölls bekräftande svar från de olika metoderna, och slutsatser kunde därmed trianguleras. / Purpose: Burnt alum shale is mining waste derived from combustion of the same rock. It exists in several places in Västra Götaland. Alum shale was previously used as filling but nowadays the use is limited thus the material is leaching heavy metals. The amount of waste normally put in landfills shall now be diminishing. Therefore the possibility to landfilling alum shale is limited. The purpose of this study is to increase the knowledge of how alum shale can be dealt with in an environmentally safe and economically beneficial way. The goal is to bring out suggestions for applications of use and ways of handling the excavations to contribute to a better environment and to achieve better financial conditions. By investigate what claims need to be achieved for the possibility of using Alum shale, useful areas of use and suitable management where brought forward. This study has been composed as a mean to get a bachelor degree in engineering, with the benefitial partner Skövde kommun. Method: Literature study, document analysis and interviews where used as research methods. Research on waste, alum shale and remediation techniques where studied in the literature study. In the document analysis, environmental study were analysed to retain knowledge of leachate. The interviews presented information of the authorities work with alum shale and experts’ suggestions of how alum shale can be used and handled. Findings: This study showed that there is other applications than landfills, and that there is methods to limit the leachate. If to be used, knowledge of the alum shale’s propensity of spreading due to stirring and relocation must be known. To inhibit leachate van be achieved by encapsulate the alum shale by waterproofing. This means that the alum shale can be used as a resource. Areas will be available for exploitation, it will not affect people in the surroundings, and the leachate to the groundwater will diminish. Implications: At minor sensitive land use, alum shale can be used as filling material, such as industrial areas and roads. This implicates waterproofing of the material. Asphalted surface, in combination of waterproofing the top surface and the vertical sides limits the leachate of metals considerably. The haul is often ruling the possibility to relocate the shale. If the alum shale, at disposal, could be used for filling purposes, the cost of purchasing new material, and outlet of new raw material does not need to burden the environment. Limitations: The alum shale studied is the one of Skövde County. The study should though be applicable to the whole of Västra Götaland. Not having the time to expand the interviews and include more people with research experience and expertise, is one of the limitations of this study. Also, carry out leachate tests could have contributed with more knowledge.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2002.

[Truncated abstract] Standard AOAC methods of chemical analysis have been used to characterize and evaluate the industrial byproducts; partly burnt chicken litter ash (CLA), totally burnt chicken litter ash (CLAT), wood ash (WA) and iron smelting slag for use as a combined liming agent and phosphate fertilizer. Rock phosphate has this function and was included for comparison purposes. All the byproducts had pH values above 9 and a liming capacity above 90% of pure lime, as a result, these materials will be effective as liming agents. Total P concentrations for CLA, CLAT, slag, and WA were 3.6%, 4.75%, 0.26%, and 0.44% respectively indicating that they could be used as P fertilizers when applied at the high rates required for liming soils. ... The RE values for all the materials relative to monocalcium phosphate (100%) for the first harvest are as follows, 50% for dicalcium phosphate, 31% for rock phosphate, 7% for partly burnt chicken litter ash, 7% for totally burnt chicken litter ash and 1% for wood ash and slag. The RE values for the second harvest were 100% for monocalcium phosphate, 80% for dicalcium phosphate, 40% for rock phosphate, 10% for partly burnt chicken litter ash, 8% for totally burnt chicken litter ash and 2% for wood ash and slag. Data for subsequent harvests are not reported due to the death of many plants. Clearly chicken litter ash has appreciable value as a phosphate fertilizer whereas wood ash and slag are ineffective. Explanations for these differences in effectiveness are discussed in the text. An evaluation of the liming effect of the byproducts indicates that they may be used as a soil amendment on acid soils and are nearly as effective as standard lime (CaCO3). Byproducts are also sources of other plant nutrients so they may be regarded as a form of compound fertilizer and liming agent.