Succinic acid, a low molecular weight dicarboxylic acid was used to leach out heavy metals from Willamette Valley soil (contaminated separately with lead, copper, and zinc) in form of water-soluble organo-metal complexes. The research tasks included developing synthetic contaminated soils representative of those found at Superfund sites and making heavy metal adsorption and desorption studies. Fixed amounts of single-metal contaminated soil were treated with succinic acid under varying conditions of pH and organic ligand concentration. Based on the total metal mobilized into the aqueous phase, the optimum values of pH and organic acid were established for each metal. Since the direct determination of all species solubilized by the organic acid solution was not possible, a computer speciation program called MICROQL was used to determine the concentration of metal species in solution containing several metals and potential ligands. The results indicate that succinic acid is capable of significantly altering the partitioning of metals between the soil and the aqueous phase. Higher concentrations of the organic acid resulted in higher removal of metal from the soil. In case of lead and copper, low pH (3.5) succinic acid flushing solution was found to be the most effective, while a pH range of 4.5-5.5 was deemed optimum for zinc. The results also established that the extent of removal of any metal depended not only upon the the stability constant of the organo-metal complex, but also on its mode of retention within the soil. / Graduation date: 1993

Lotsbroverket is the largest wastewater treatment plant on the Aland Islands and it isdesigned for handling wastewater from approximately 30 000 persons. In 2011,Lotsbroverket produced about 2800 m3 of dewatered sludge. The sewage sludge that isproduced is transported to a contractor where it is processed to eventually be used e.g.in the construction of green space. This study aims to investigate available applicationoptions in terms of the sewage sludge that is produced in Lotsbroverket. The main aimis to study the feasibility of using the produced sewage sludge as a fertilizer in theagriculture of the Aland Islands.The sludge already fulfills limit values for heavy metals in accordance with the Act"The Aland Government´s directive on the use of sewage sludge in agriculture." Inorder to clarify the sludge content of pharmaceutical and organic substances it isrequired that the substances are identified and a risk assessment is performed. In theliterature it is found that the risk of human exposure to these substances is low if thesludge is treated appropriately. Suggested appropriate treatment of the plant's sludge isthermophilic digestion whereby also pathogens are killed.The soil of the Aland Islands has a high content of phosphorus. Since 1995 there is anenvironmental program to which currently 95% of the island's farmers are connected.The program controls the use of fertilizers i.e. by setting maximum permitted levels ofphosphorus. Since sewage sludge contains relatively much phosphorus it may be alimitation of the use of sewage sludge on agricultural land of the Aland Island. That iswhy it would be suitable to use the sludge with a different fertilizer in order to obtainthe proper fertilizing properties.In Europe, the use of sewage sludge in agriculture is relatively widespread. Severalcountries have less strict laws regarding the sludge content than the Aland Islands.Because large amounts of fruits and vegetables annually are imported into the island,there is reason to believe that the population already consumes products grown onsludge treated soils. Several of the farmers on the Aland Islands are currently scepticalin terms of using sewage sludge in agriculture, mainly due to uncertainties in the sludgecontent. Regarding the certification of Lotsbroverket in accordance with the Swedishcertification system REVAQ no barriers have been found. To ensure that a certificationis possible, however, further investigations are required.

The research focuses on the fate of heavy metals and their emissions from pulp mill recovery boilers. Heavy metals are extremely toxic and cause adverse effects on human health. There is limited information about factors affecting heavy metal vaporization from recovery boilers, in which spent pulping liquors, (also called black liquor) is burnt. The heavy metals are present in trace quantities in black liquor. They are emitted in the air as submicron particles, and their amount of emission depends on the input of metals into the recovery boiler, volatilization of metals in the boiler and the efficiency of the electrostatic precipitator (ESP) to remove the metals. The heavy metals vaporization from different recovery boilers vary widely and the reason is not known. My thesis will focus on determining what conditions affect the volatility of the heavy metals, and whether differences in heavy metal vaporization are due to differences in boiler operating conditions or the composition of the liquor. I will examine black liquor pyrolysis, combustion and gasification in well-controlled laboratory conditions. I will analyze three different black liquors. The liquors will be spray-dried and burnt or gasified in a laminar entrained-flow reactor at high temperatures of 1000-1100C and residence times ranging from 0.5 to 1.5 s. Equilibrium calculations will be performed to determine the distribution of heavy metals and species under set conditions from previous devolatilization experiments. The equilibrium calculations will serve as a useful tool for prior estimation of the distribution of heavy metals. The impact of different liquors on volatilization of heavy metals in the experiments will be determined. The char residue and condensation aerosol (fume) particles from each experiment will be analyzed using ICP-AES. The amount of heavy metals volatilization during combustion and gasification will be determined based on the amount of the metals in the char residues and fume particles. Based on the results of the experimental study combined with data from the equilibrium analysis program the main cause of variability in heavy metal vaporization can be found. Also the boiler operating conditions can be studied to determine its affects on the volatility of the heavy metals.

Although soils developed from ultramafic parent materials have significance to agriculture, ecology and health, their bio-geochemistry is poorly understood. The mineralogical and bio-geochemistry of soils formed from the ultramafic parent materials of the Great Dyke, Zimbabwe and Gillespie County, Texas was investigated. The objectives were to determine the mineralogical and bio-geochemical properties of the soils in order to assess the potential impact and challenges to agriculture, and environmental quality. Soil samples were taken from the crest, shoulder, footslope and the toeslope. Chemical analyses were performed by nuclear and spectroscopic techniques. Mineral characterization was conducted by x-ray diffraction (XRD) and spectroscopic techniques. Microbial whole-community structure was determined by the fatty acid methyl esters (FAME) technique. The results indicate wide chemical and mineralogical compositions among the studied sites. The soils contain relatively high concentrations of heavy metals (some sites contain Cr(VI)), but low levels of K and Ca. The highest concentrations of trace metal were associated with chromite, Fe oxides and serpentinite. The concentrations of Mg were higher than those of Ca and varied between Zimbabwe and Texas soils largely due to the parent materials. Unique to these soils is the occurrence of talc, serpentine, chlorite, Fe-rich smectite, amphiboles, pyroxenes, Fe and Cr oxides in relatively large amounts. These soils also lack micas and have neglible amounts of kaolinite and feldspars. Palygorskite and serpentine occurred in specific soil horizons and at specific landscape positions. FAME profiles indicate that the soil microbial community structure is predominantly bacteria and fungi (including arbuscular mycorrhiza fungi) at each landscape position across the transect. Biomarkers for actinomycetes were undetectable. The proportions of Gram-positive bacteria were higher than those of the Gram-negative bacteria. Very low levels of nutrients (Ca and K), higher Mg/Ca molar ratios, and the relatively high concentrations of heavy metals in these soils impact agricultural productivity. High concentrations of heavy metals, the presence of the Cr(VI) as well as its great potential to form in these soils might impact microbial activity and environmental quality. The occurrence of fibrous minerals (e.g serpentine and amphiboles) in these soils will likely impact human health.

Electroplating industry is one important industries in Taiwan. Its wastewater has lead to pollution of the river, ocean, and underground water. Thus, the reduction of the concentration of heavy metals such as Cu, Zn, Ni, Cr, Pb etc. from wastewater is critical. Conventional strategies to remove the heavy metals involve adding abundant chemical agents which results in largy quantity of heavy metal sludge. Secondary pollution might occur as due to the heavy metal sludge contacted with acid. Aquatic plants have been shown to uptake the heavy metals from the surrounding environment. This unique character is different from the conventional approach and could be applied for removing the heavy metals in wastewater.This study used an aquatic plant, Najas graminea Del, to remove the heavy metals from the prepared metal solution and electroplating wastewater. Our data revealed that the relationship between the specific adsorption and residual concentration of the heavy metal was best described by the Langmiur adsorption isotherm curve. The value of maximal adsorption capacity (Ymax) in copper is 58.1 mg/g. Without buffering, the sequential order for the Ymax in the prepared metal solution is Cu > Pb > Cd> Ni > Zn. The value of Ymax was with significantly reduced under buffering circumstance as compared with that no buffer. In the electroplating wastewater containnig copper from company A, the value of Ymax was 20.7 mg/g, which was much smaller in prepared copper solution (Ymax =33.1 mg/g). Our further investigation showed that the background contaminatants especially iron in the electroplating wastewater have significant contribution to this discrepancy. In other set of experiments, we found that there is no significant difference between the electroplating wastewater and prepared solution for the adsorption of Ni. Our results provide useful information the understanding the process for the Najas graminea in adsorption the heavy metals from electroplating wastewater. Futhermore, the application of Najas graminea to remove the pollution from wastewater can protect the enviroment from pollution. This innovative concept has the potential in practical application and could be trasferred into a novel technology to substitute the conventionally physical or chemical treatment for the electroplating wastewater.

Heavy metals are one of the most important environmental pollutants. In recent years, many low cost stretages of bioremediation for contaminated sites by heavy metals, such as fungi, bacteria and plants have been investigated for their biosorption capacity towards heavy metals. The uses of plant species for remediate contaminated sites by heavy metals are so called phytoremediation. The purpose of the first parts of this study are to (1) evaluate bioavailability of Cadmium (Cd) in contaminated soil and phytoremediation potential by three plant species, Vetiveria zizanioides, Pteris multifida, and Alternanthera philoxeroides (Mart.), and (2) realized the influence of photosynthetic bacteria (PSB) on the uptake of Cd in the three species. The results showed that the Alternanthera philoxeroides (Mart.) could accumulate the highest concentration of Cd among the three species, in which the Cd concentration of plant tissue increased with the concentration in soil. The highest concentration of Cd (164.9 mg kg-1) was found in the below-ground parts of Alternanthera philoxeroides (Mart.) at the 8th week of culturing period. However, the species of Vetiveria zizanioides could accumulate the largest total Cd, up to 547.5 £gg/ plant, which thus extracted the greatest amounts of Cd from the soil. Therefore, in the first part of this study the species of Vetiveria zizanioides was concluded to be the best accumulator among the three plant species. In addition, the concentration of Cd in the species of Pteris multifida was found significantly increased after PSB was added into the soil, but the plants died later due to Cd stress. The experimental results also showed that PSB seemed to be not suitable for each species used in this study to accumulate Cd from Cd-contaminated soil. In the second part of this research, both pot and field experiments were conducted to (1) evaluate bioavailability of copper (Cu), lead (Pb) and zinc (Zn) in contaminated soil and phytoremediation potential by domesticated plants, Bidens pilosa and Passiflora foetida inoculated with arbuscular mycorrhizal (AM) fungi, and to (2) compare the results of pot and field experiments. The plant species of Bidens pilosa inoculated with AM fungi had significantly higher Cu concentrations in the shoots and roots than non-inoculated plants. The plant species of Passiflora foetida inoculated with AM fungi also had significantly higher Cu and Pb concentrations in the roots than non-inoculated plants. When we found that the root dry weight of Passiflora foetida inoculated with AM fungi dramatically increased, the concentrations of Cu, Pb and Zn in the root of the plant species increased by 9-14 times, comparing with the plants without inoculation of AM fungi. The AM fungi have potential either to promot plant growth or to increase heavy metal accumulation. The values of element translocation proportion from root to shoot was Zn>Cu>Pb for the plant species in both pot and field experiments. For both experiments, the results of pot test and field test were significantly different. The concentrations of pot tests were found higher than the field tests, and some values of pot tests were even found significantly greater than those in the field tests. In the third part of this study, the field experiments were conducted to test the feasibility of using domesticated vegetations for phytoremediation of the contaminated farmland. The objectives of this study were (1) to acquire information about the ability of five plant species growing wild in the polluted area to accumulate Cu, Pb and Zn, (2) to investigate the season effects on phytoremediaton of five plant species and evaluate the total uptake of heavy metal, and (3) to run both pot tests and a field trial of phytotremediation to compare their differences. The experimental results showed that three maximum toxic elements in a pot were 3020 mg kg-1 Pb, 232 mg kg-1 Cu and 1012 mg kg-1 Zn respectively. The Cu concentrations of the five plant species collected from the polluted plots ranged from 0.7 to 17.43 mg kg-1. The range of variation of Pb in plant tissues was measured varied from 2.29 to 81.65 mg kg−1, while a wide range of Zn concentrations was found from 12.84 to 192.85 mg kg-1 among the plants collected at the contaminated plots. In comparison to winter season, the Zn concentrations in Broussonetia papyrifera, Passiflora foetida and Saccharum sinensis collected in summer season was significantly higher. The higher Cu concentrations were obtained in both plant species of Bidens pilosa and Mimosa diplotricha in summer season. However, Pb concentrations in Saccharum sinensis collected in winter were significantly higher than those in the same plant species collected in summer. Bidens pilosa was also found having the highest total amount of Cu and Zn. The highest total amount of Pb was found in Mimosa diplotricha. For both plant species, both of the pot and field tests were different.

Thesis (M.S.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references (leaves 86-88).

Thesis (M.S.)--Bowling Green State University, 2009. / Document formatted into pages; contains viii, 38 p. : ill. Includes bibliographical references.

This research study addresses a problem of water pollution caused by heavy and toxic metals Cd, Cr, Cu and Pb. The thesis proposes the use of the technique of phytoremediation using Phragmites australis (PA) plants that have the capacity to absorb and to accumulate such metals in their roots and leaves. The metal uptake and their location of accumulation in the PA plants were determined using flame atomic absorption spectroscopy (FAAS) and transmission electron microscopy (TEM) respectively. Leachates from contaminated plant biomass were mixed with silver nitrate to assess the manufacture of metal nanoparticles as an added value step in the process from remediation to biomass disposal. Silver nanoparticles were readily manufactured by the leachates without, with the exception of copper, any incorporation of the pollutant metal. The presence of copper in the manufactured silver nanoparticles may be of some commercial use. The results obtained show that PA plants will accumulate toxic metals when in hydroponic culture and that the majority of the accumulated metals are sequestered in the roots and do not enter the aerial parts of the plants in significant amounts. Silver nanoparticles were manufactured from the biomass using a low energy route with no additional chemicals, apart from silver nitrate thus reducing the environmental load that would otherwise be present if a chemical means of nanoparticle production was used.

D. Tech. Chemical Engineering. / This research aims to improve the current state of wastewater treatment technologies by exploiting the characteristics and capabilities of nanomaterials. Also, it aims at protecting the environment and human health by minimizing exposure of toxic contaminants found in waters sources by treatment with cheaply engineered materials. The nanocomposites that will be employed in this study have shown to be effective for removing a number of heavy metals from aqueous solutions during trial experiment. The study is therefore carried out to reduce the water scarcity in South Africa by minimizing the contamination of remaining water resources. With industrial effluents the main targets, the aim is to design systems that will enable industries to recycle their wastewater instead of discharging into the environment. This study will therefore benefit the communities who solely depend on surface and ground water and again it will safe industrial bodies high costs of treating their wastewater with ineffective conventional methods. The research focuses on the application of polypyrrole-clay nanocomposites for removing heavy metals from wastewater streams. The research conducted hereby highlights the application of polymer based nanocomposites as suitable adsorbents for the remediation of the toxic chromium(VI) [Cr(VI)] from water. The work describes the preparation and characterization of the nanocomposites, their application to wastewater laden with Cr(VI) in both batch and continuous adsorption and finally understanding the adsorbent-adsorbate interactions and sorption mechanisms under various physico-chemical conditions.