Edward Loffill

Residence time distribution and the investigation of bed movement in a continuously operated upflow filter (COUF) for tertiary wastewater treatment.

This paper describes an investigation to define the liquid phase flow regime in a continuously operated upflow filter (COUF) together with an assessment of the relative motion of the solid (filter media) phase. The importance of such measurements in the development of a model for these systems, including aerated biological filtration versions is discussed. Initial work was carried out on a model-scale demonstrator unit using Rhodamine WT fluorescent dye tracing for liquid phase studies. Initial outputs show that the liquid phase residence time distribution (RTD) is well approximated by a plug flow assumption. The pattern in which individual particles of the bed move during the operation of the COUF was also investigated on the demonstrator using colored beads as a tracer. The gross movement of the bed and the internal mixing regime described can be regarded as analogous to RTD. Techniques were developed whereby bed movement in the cleaning process could be measured and assessed over time, leading to the generation of 3D bed movement visualisation plots. This work could potentially lead to developments of technologies that could better clean the media and lead to a more even bed movement allowing the filter to operate more efficiently.

Settlement Prediction of Model Piles Embedded in Sandy Soil Using the Levenberg–Marquardt (LM) Training Algorithm

This investigation aimed to examine the load carrying capacity of model piles embedded in sandy soil and to develop a predictive model to simulate pile settlement using a new artificial neural network (ANN) approach. A series of experimental pile load tests were carried out on model concrete piles, comprised of three piles with slenderness ratios of 12, 17 and 25. This was to provide an initial dataset to establish the ANN model, in attempt at making current, in situ pile-load test methods unnecessary. Evolutionary Levenberg–Marquardt (LM) MATLAB algorithms, enhanced by T-tests and F-tests, were developed and applied in this process. The model piles were embedded in a calibration chamber in three densities of sand; loose, medium and dense. According to the statistical analysis and the relative importance study, pile lengths, applied load, pile flexural rigidity, pile aspects ratio, and sand-pile friction angle were found to play a key role in pile settlement at different contribution levels, following the order: P > δ > lc/d > lc > EA. The results revealed that the optimum model of the LM training algorithm can be used to characterize pile settlement with good degree of accuracy. There was also close agreement between the experimental and predicted data with a root mean square error, (RMSE) and correlation coefficient (R) of 0.0025192 and 0.988, respectively.

Storm Water Best Management Practices into the Existing Urban Landscape - Systems for Controlling Sediments

The operation of an ‘advanced’ hydrodynamic vortex separator (AVS) designed for stormwater sediment interception has been examined using particle capture and retention efficiency testing and dye tracer testing. For retention efficiency in particular (referring to the efficiency with which a chamber retains pollutants following capture) the results are compared with those for other configurations, including simple vortex and gravity separation devices. The results show how the collection and retention efficiencies of the AVS are enhanced through the presence of a quiescent zone in the base where solids are stored. A simple model of system operation is considered, based on the surface loading rate of the active region and the particle sedimentation velocity. It is concluded that a comprehensive model of system performance needs to take into account a variety of factors, including the detailed characteristics of the sediment material and the hydrodynamic characteristics of the specific separation device in question.