The removal of metals from potable and wastewater to regulatory standards presents unique challenges. Conventional treatments, chemical precipitation, adsorption by activated carbon, ion-exchange, electro-chemical and reverse osmosis can be expensive or ineffective at low concentrations. Recent research has shown that biosorption by low cost biomass can be an effective alternative. Biosorption is the passive (non-metabolic) uptake and concentration of metals by non-viable biological materials. In this work, natural materials and shellfish processing wastes were physiochemically characterised to identify products with suitable characteristics to perform as biosorbents. Brown seaweed (FllCliS vesiculosus), Douglas fir wood bark (Pselldolsllga menziesil), peat and carapace from the edible crab (Cancer pagurus) were assess~d for Cu(II) removal as a function of time and concentration. Mechanically and commercially milled carapace (MMC and CMC) were the most efficient, removing >95.0 % within 40 minutes from 100-1000 mgIL Cu(II) solutions. Extended studies showed MMC was also applicable for use in biosorption columns and effective for the removal of Cd(II), Hg(II), Pb(II), Ni(lI) and Zn(II), at concentrations ranging from 1-1000 mgIL. MMC and CMC were compared with chitin, chitosan, Darco© and Norit© activated carbons and Dowex© ion-exchange resin for the removal of Cu(II). Dowex© and Norit© were the most efficient commercial sorbents removing up to 99.9 % from the 1-1000 mgIL. MMC and CMC compared favourably and were effective over the 1-4000 mg/L range and suitable for use in acidic solutions (pH 4.2-4.7). Sorption of Cu(II), Hg(II), Pb(II) and Zn(II) by MMC were predicted reliably (R2>0.99) using a pseudo-second-order model, with rates of 1.34, 14.6, 1.37 and 1.30 mg/mg/min respectively. An intra-particle diffusion. model and SEM-EDAX microanalysis revealed that the biosorption of metals proceeds via rapid adsorption-precipitation to surface binding sites, followed by rate limiting intra-particle diffusion. Equilibrium uptakes were evaluated using the Langmuir, Freundlich and Redlich-Peterson adsorption isotherm models. The best fits were obtained for the Langmuir model with 416.7, 86.2, 30.5 and 14.6 mg/g MMC for Pb(II), Cu(II), Zn(II) and Hg(II) respectively. The results show that biosorption of metals is complex and proceeds via adsorption, precipitation, absorption, and ion exchange depending on pH, initial concentration and material conditioning. Although CMC was marginally more efficient than MMC, MMC is less labour intensive and more cost effective to produce. Therefore, MMC offers significant potential as a viable metal biosorbent and merits further development.

The public water supply in Germany is mainly based on groundwater, and great care is taken to protect these water resources. A major challenge is, however, the remediation of polluted aquifers. Such is the case at a former gas works site in Karlsruhe, Germany. The "Gaswerk Ost" of the local gas and water supply company, the Stadtwerke Karlsruhe, was in operation for nearly 80 years until it was closed down in 1965. Unwanted by-products from the gas production still contaminate the soil and groundwater of this site. The main contaminants are benzene and polynuclear aromatic hydrocarbons (PAH) such as acenaph-thene, acenaphthylene, fluorene and fluoranthene. For remediation a novel passive methodology was planned. It was decided to install a funnel and gate system to purify the contaminated groundwater in situ by letting it pass through subterranean activated carbon reactors located downstream of the polluted site. During the construction of the remediation system a further pollutant, vinyl chloride (VC), was detected in the groundwater, a substance which could not be removed adequately by the technology employed. The objective of this research project was to find out whether the PAH and vinyl chloride could be removed from the groundwater by UV irradiation prior to the activated carbon filtration. Investigations consisted of two parts: laboratory experiments were conducted to prove the general degradability of the pollutants and field experiments were earned out to confirm these results on a pilot scale. In addition to sole UV irradiation, ozonation and advanced oxidation processes (AOPs) such as UV/aeration, UV/hydrogen peroxide and UV/ozone were performed in the laboratory to generate highly reactive hydroxyl radicals. For the contaminants present at the gas works site, the individual molar absorption coefficients were determined at 254 nm to estimate the degradation performance by direct photolysis at the main emission line of the UV lamps used for the irradiation experiments. It could be shown that all investigated substances were degradable in model test solutions prepared with reverse osmosis water, the degradation of PAH being significantly better than that of benzene and VC depending on the absorption of UV light of the individual substances. During the irradiation of acenaphthene the detection of by-products with an aromatic character showed that no complete mineralisation could, however, be achieved in an acceptable period of time. Degradation experiments performed in tap water as well as in groundwater showed slower degradation behaviour due to the high carbonate and bicarbonate concentrations and a high organic carbon content, mainly resulting from humic substances in the case of groundwater. The high iron concentration of the reduced groundwater led to an increase in turbidity during irradiation, since iron II was oxidised to iron III. In contrast to UV irradiation only, better results were achieved with combined treatment methods and with ozonation. For all methods tested in the laboratory the "Electrical Energy per Order of Magnitude" (EEO) was calculated from the degradation data, ozonation being most efficient for all investigated substances with regard to the energy consumption. On the basis of the laboratory findings it was decided to perform not only UV experiments at the gas works site but to extend the in-situ investigation programme by including ozonation. With UV irradiation the concentrations of the PAH acenaphthylene, fluorene, fluoranthene and pyrene could be reduced by nearly 90%. The total efficiency of UV irradiation in this specific groundwater was, however, unsatisfactory because the main contaminant acenaph-thene was removed by only 50% to a concentration of approximately 35 g/l (remediation target value = 0.2 g/l) although 1.33 kWh per m3 were applied with four lamp modules, each containing six lamps. In contrast to this, ozonation resulted in a complete elimination of VC and PAH as well as nearly 90% removal of benzene, thus confirming the laboratory findings. As almost all contaminants could be removed by ozonation only, combined UV/ozone treatment was not applied in situ. Ozonation technology was found to be the most favourable method for the removal of contaminants present at the former gas works site in Karlsrahe based on its practicability, economic advantages and high efficiency.

This project investigates phytoremediation at a disused fire training runoff lagoon at an ecologically sensitive area in Southern England called Horsea Island. The sediments in the semi-saline lagoon were highly contaminated with over 145,000 mg/kg Dry Weight (DW) Diesel Range Organics (DRO) and were classed as carcinogenic and unsafe for human exposure. Phytoremediation was attractive as an inexpensive and in situ remediation method. However there were limited field studies examining such extremely contaminated conditions. Initial mesocosm studies indicated that both Phragmites australis and Typha latifolia were able to grow in this sediment without the need for additional nutrients and P. australis was subsequently used for test planting in the lagoon. Ex situ greenhouse microcosms as well as an in situ full scale trial was carried out and the response of DRO and microbial populations were investigated over a 15 month period. Using a novel colourmetric plate test developed during this study, planted sediments in both the microcosms and Horsea lagoon showed not only an increased diversity but also an increased number of hydrocarbon-degrading bacterial isolates when compared to unplanted sediments. However, although the overall DRO concentrations fell in both the in situ and ex situ systems in times of hot weather and low water levels, there were no significant differences between planted and unplanted sites. There was also no difference between microbial numbers in planted and unplanted sites in either the microcosms or Horsea lagoon however, the mesocosms that had been growing for three years showed significantly higher numbers of bacteria, hydrocarbon-tolerant bacteria and hydrocarbon-tolerant fungi as well as elevated numbers of fungi in the planted sites. This indicates that phytoremediation may require a longer period of time to enhance degradation in such conditions.

Sugar factories are a significant source of water pollution, particularly in developing countries such as Pakistan, where the sugar industry is the second largest after tanneries. The wastewater is disposed of untreated to the environment, since traditional wastewater treatment processes are capital-intensive, energy-demanding and complex in operation. The common approach is to use waste stabilization ponds or lagoons mostly operated on complete retention basis. This work is an attempt to highlight the possibility of effectively applying wastewater lagooning process utilizing the inherent organic contents of sugar factory wastewater with the aid of an algae-bacterial consortium (ABC) to investigate its capacity to utilize this resource to produce renewable fuel while de-polluting wastewater rather than it being a liability to be disposed of. A lagoon photo tank (LPT) resembling a prototype raceway lagoon was designed and used to carry out mass cell cultivation on a sugar-oriented medium for the assessment and inter-optimization of the process conditions such as temperature, incident light (IL), pH, dissolved oxygen (DO). The evaluation of the process performance was observed via the analyses of parameters such as chemical oxygen demand (COD), total organic carbon and cell mass growth. The first part of this study was related with the baseline assessment of LPT process conditions using distilled water as well as sucrose solution or sugar water to establish basis for a priori analysis of simulated sugar factory wastewater (SSFW) carried out in the second part. The suitability of the dosing of copolymer Polyacrylate polyalcohol was optimised through a series of trial runs to aid in the immobilization of mono or mixotrophic cultures of green algae Chlorella Vulgaris and bacteria Pseudomonas Putida at the surface of LPT in order to influence reduction in the organic concentration of SSFW. This research study has contributed to the knowledge base of the concerned area of study with respect to hitherto unknown application of copolymer Polyacrylate polyalcohol, which showed viable characteristics in the cultivation medium in terms of cell immobilization at the surface of LPT resulting in the formation of growth-conducive copolymer-algae matrices leading to the rapid growth of the cell mass with increased process efficiency. This process optimisation resulted in SSFW depollution by around 89% along with energetic biomass growth with a calorific value of 27 kJ g1 and at an optimum growth rate of 1.2 d1 suggesting towards the potential of copolymer addition in the system to enhance the efficiency of the organisms inducing optimum substrate utilization.

M. Tech., (Faculty of Applied and Computer Science), Vaal University of Technology / There is huge concern in the mining and industries to manage wastewater prior to discharge into the environment. It is generally cheaper and cost reducing for industries to treat its own wastewater before discharging to the local authority sewer. Dense Media Separation (DMS) Powders Company produces milled and atoms ferro-silicon by pyro-metallurgical process. DMS Powders uses municipal water for all processes taking place in the plants. The water used during the processes of milled and atom ferrosilicon powder is discharged into the environment without being treated. By treating this process wastewater before discharging will result in reducing the water consumption by recycling and the penalty costs for polluting the environment. The primary objective of this study is to find suitable method for treatment of DMS Powders’ process water using selected membrane processes. Membrane processes are better choice compared to traditional physical/chemical treatment processes, due to their advantages of approving water quality, no phase change, no chemical addition and simple operation. Two commercial membranes namely; NF-, and SW30HR are used in the treatment of DMS Powders process water. These membranes were purchased from (Dow/Filmtec) Manufacturing Company (Pty) situated in South Africa. Membranes were characterised by Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and Fourie Transform Infrared (FTIR) instruments. For synthetic water three membranes (NF- , NF90, and SW30HR) are investigated for the study. The fluxibility indicated that NF- membrane has higher flux compared to NF90 and SW30HR membranes. All the three membranes were very good in terms of rejection on single salts. Fouling was studied on DMS Powders process water. Concentration polarization was formed on NF- and SW30HR membranes investigations on selected membranes conclude that NF- membrane will be the suitable membrane for treatment of DMS Powders process water because of its high fluxibility and rejection. Discharged effluent of DMS Powders could comply with the legislature and environmental pollution could be minimised. The study revealed that fouling does occur during treatment of process water. SW30HR showed that M9 Plant had more fouling for M9 samples than other Plants (M8A and M8B). It was because of higher concentrations in suspended solids.or M8A, M8B and M9 process water.

This thesis is concerned with the chemical modification of polymers in the preparation of a library of materials which exhibit altered surface properties as a result of the surface chemical functionality, with particular emphasis on the development of materials that control biofouling and are antibacterial. Chemical modification of crosslinked polystyrene, in film and microsphere form, was carried out by carbene insertion followed by diazonium coupling. This provided access to a collection of materials with varying surface chemistry, whilst the bulk properties of the polystyrene substrates were maintained. Synthesis of the diaryldiazo and the diazonium salts used to perform the surface modifications is described, as well as the preparation and characterisation of the materials. Analysis of the ability of the materials to adsorb and bind the protein bovine serum albumin (BSA) is presented with data obtained from two methods of observation. Quartz Crystal Microbalance with Dissipation (QCM-D) and a protein assay based on the change in optical density of a BSA/PBS solution are used to demonstrate how the specific surface chemistry of the materials influences the ability to adsorb and bind protein. The behaviour of the materials was time dependent and was rationalised with respect to the surface water contact angle and the calculated parameters polar surface area and % polar surface area of the functional groups added to the surfaces. Finally, penicillin loaded materials were prepared and their antibacterial activity was tested against E. coli and S. aureus, demonstrating that the antibiotic is still active from within the polystyrene scaffold.