The biological tests of biochemical methane potential (BMP) and dynamic respiration index (DRI) are recommended by the EA monitoring guidance (Environment Agency, 2005) to evaluate the performance of Waste Disposal Authorities (WDAs) in diverting biodegradable municipal waste (BMW) from landfills by means ofmechanical and biological treatment (MBT). Because the biological tests are complex and timeconsuming to conduct, chemical tests may provide rapid surrogate measurement of biodegradability. The relative contents of the cellulose, hemicellulose and lignin determined by fibre analysis have been used to assess the degree of decomposition in landfills. However, their relationship with biodegradability has not been well investigated and understood, particularly for mixed BMW. In this study, BMP and DR!, gravimetric test and chemical tests (fibre analysis and TC, TN) were conducted in parallel using a variety ofMBT waste samples collected from anaerobic and aerobic degradation (composting) experiments in which real MSW or BMW was used. Two laboratory scale composting reactors were built where four batches of composting experiments were conducted. ~ The results ofthese tests were c~1npared to identify the correlations between them, especially the correlations between the biological tests and fibre analysis. Evaluations are made based on this study for tests ofBMP, DR!4, gravimetric test and TCITN ratio. The main findings are: (1) Based on the good correlation observed between fibre analysis and biological tests for the treated waste, three linear model equations are proposed to predict the biodegradability upon (C+H)/L ratio or CIL ratio for the BMW during or after the MBT process, thereafter to predict the amount ofBMW diverted by MBT in terms of anaerobic biogas potential; (2) The cellulose and hemicellulose contents or the (C+H)/L ratio ofthe untreated BMW (fresh mechanically pretreated BMW) were not found to correlate directly with biodegradability. This is consistent with the former findings on the specific waste components (untreated waste) by Eleazer et al. (1997) and Godley et al. (2005). It is suggested that untreated BMW and treated BMW need to be investigated separately in examining the relationships between relative fibre content and biodegradability.

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The mobility of radionuclides through the Geosphere depends greatly on the sorption of radionuclides to the host rock. However, the presence of colloidal particles may influence the transport of radionuclides. Given a stable and mobile colloidal suspension which sorbs radionuclides onto its surface, the radionuclide may be transported along with the colloidal suspension. Given an irreversible interaction, radionuclides may be transported until the colloids flocculate. A reversible interaction, may lead to a scenario where the radionuclide is immobilised by sorption to the host rock. The work presented herein provides insight to the reversibility of the interaction of Cs+, Ni2+ and Eu3+ with two colloidal suspensions, boehmite and montmorillonite. The main difference between the colloidal phase and the solid phase of a mineral is the surface area to mass ratio, greater for the colloidal phase, as shown by the results herein. Assuming equal chemistry between colloidal and solid surface, sorption experiments have been carried out to relate the distribution ratio, Rd, for colloids and for solids with the ratios between surface areas. An attempt to develop a mathematical expression was made. The effect of humic acid on the sorption of metals onto colloidal boehmite was investigated. In all cases, the sorption of metals onto boehmite was hindered by the presence of humic acid. The linear additive model was tested on the experimental results. The transport of radionuclides associated to inorganic colloids has been assessed by means of column experiments. A radiometric technique consisting of radiolabelling inorganic silica colloids with 152Eu spike was used to detect and quantify the migration of silica colloids through a sand column. Furthermore,the same method was used to investigate the migration of 137Cs associated to silica colloids through a sand column. The mobility of the radionuclide was found to be enhanced by the silica colloids.

No description available.

No description available.

In this work, the effect of wastewater feed composition on the membrane fouling rate of 5 and 20 kD ultrafiltration ceramic membranes was investigated using statistical analysis of the experimental results (two way factorial design), with particular regard to the protein (meat extract and peptone), sodium alginate and calcium chloride components. A mathematical model was used to determine the major membrane blocking mechanisms and the effect of different feed components concentration on the blocking mechanisms. Polysaccharides are the major fouling compounds in extracellular polymeric substance (EPS), while protein compounds are an important part of EPS membrane fouling, their effect increases in the presence of polysaccharides. Sodium alginate calcium solutions fouled the membrane more severely, causing twice the increase of resistance (on average) than did meat extract calcium solutions. This study showed that irreversible fouling was the major fouling type in alginate calcium filtration experiments, while less of the fouling in the meat extract calcium filtration experiments was irreversible. The effect of changing the artificial wastewater components concentration on the fitting accuracy of the blocking models for the 20 kD pore size membrane was almost the opposite of the 5 kD pore size membrane. Increasing the calcium concentration increased the predication accuracy of the intermediate and complete blocking models, while the increase in alginate concentration reduced the cake filtration model prediction accuracy. After each experiment, the membrane was cleaned using different cleaning chemical concentrations. The best cleaning was achieved with increasing sodium hydroxide concentration in the cleaning solution. In general higher cleaning temperature and increasing cleaning time improved the membrane recovery, nevertheless; the effect was not as noticeable as the effect of increasing sodium hydroxide concentration.

This work presents the concept development, implementation and first practical demonstration of a new pressure intensifier for energy recovery in small-scale seawater reverse osmosis systems, and the simplified system configuration it requires. The new concept has great potential to reduce the specific energy consumption of small-scale seawater reverse osmosis systems. A mathematical analysis to study pressure intensifiers for energy recovery in reverse osmosis applications was developed. The analysis was used in the design and modelling of the energy recovery device. A first prototype was built and subsequently demonstrated in a system desalinating seawater over a wide range of electrical input power stretching between 286 and 1196 W, producing up to 286 L/h of freshwater with specific energy consumptions in the range of 3.5 to 4.5 kWh/m^3. The flat specific energy characteristic makes the device attractive for renewable-energy-powered systems without energy storage. The prototype implementation was realised through modifying a Clark pump, but the new concept is fundamentally different. The new device recovers energy from the concentrate stream, which it then uses to suck in and pressurise seawater, relying purely on its piston area ratio, and thus eliminating the need for a low-pressure feed pump.

Endocrine disrupting chemicals such as steroid estrogens and alkylphenol polyethoxylates entering the environment via regular domestic or industrial discharges have been demonstrated to cause feminization of aquatic organisms at trace levels. Despite these discharges, the solid-end product of wastewater treatment i.e. digested sludge, poses a potential source of these compounds in the environment when sewage sludge is recycled onto land. Greater concentrations of alkylphenolic metabolites such as alkylphenols and short-chained one to three ethoxy units, ethoxylates have been reported to occur in digested sludge than the parent compounds. This study investigates the fate and behaviour of these chemicals in mesophilic and thermophilic anaerobic digestion by using primary sludge and a mixture of primary and secondary sewage sludges. The analytical methodologies used for the determination of these endocrine disrupting compounds allowed accurate quantification at microgram per kilo of dry-sludge weight concentrations in the complex sludge matrices. Four mesophilic and two thermophilic semi-continuous lab-scale anaerobic digesters were examined. In addition, acclimated sludges were dosed with high nonylphenolic concentrations to observe the capacity of biomass to remove these compounds. Cont/d.

Landfill leachate is collected and treated before discharge to protect the environment from a potential toxic cocktail of substances. In the U.K. biological treatment is the favourite technology for rendering landfill leachate safe due its simple design, effective handling of varying chemical loads and relatively low operating costs. Biological treatment is effective at reducing the concentrations of ammoniacal-nitrogen and the biological oxygen demand (BOD) to acceptable levels for discharge. Even though the ammoniacal-nitrogen and BOD levels have been reduced there still remains a considerable quantity of refractory organic chemicals and inorganic ions. Heavy metals tend be present in very low concentrations. A view has developed that these effluents potentially pose a risk to the aquatic environment due to the presence of these compounds. Cont/d.

Removal of natural organic matter (NOM) is an ever growing challenge for water utilities as many surface waters used for drinking water in the UK exhibit increasing organics levels and it is well known that these organics can lead to problems such as water colouration, unpleasant odour and taste, bacterial growth and disinfection by-products (DBPs) formation. NOM is traditionally removed by coagulation, however in the case of hydrophilic organic matter rich waters the performances of these processes are not able to remove sufficient organic matter leading to potential failures of DBP regulations. Here two advanced oxidation processes (AOPs) UV/H2O2 and TiO2 photocatalytic oxidation were studied to investigate how they could be integrated in a drinking water flowsheet to meet this challenge. Substantial structural changes in the organic matter were observed: loss of aromaticity and double bonded character, shift towards lower molecular weight (MW) more hydrophilic compounds and formation of oxygenated by-products. Although hydrophobic rich waters seem more suitable to AOP treatment as preferential attack of high MW hydrophobic compounds was demonstrated, no correlation was found between physical properties of nine NOM surrogates and removal by UV/TiO2. Dark adsorption onto TiO2 was shown to remove preferentially high molecular weight hydrophobic anionic compound such as tannic acid. UV/H2O2 combined with coagulation did not show any significant benefits in NOM removal as UV/H2O2 appeared to target similar components as coagulation (high MW, hydrophobic and charged) and to form by-products recalcitrant to coagulation. The combination of both AOPs with fresh GAC showed moderate benefits in Abstract ii trihalomethane formation potential (THMFP) and non purgeable organic carbon (NPOC) removal highlighting the role of size and surface chemistry on adsorption onto GAC. Biodegradability of the water did not exhibit any significant change after both AOP treatments within the studied conditions possibly due to insufficient UV irradiation and presence of organics recalcitrant to biodegradation.