In this paper we present the educational process of Lin2k, a Web‐based tool, which supports distant asynchronous, written, peer‐collaboration in a case study. The tool constitutes an open learning environment that endows engineering students with collaborative competencies, necessary for their successful shift to professional practice. Students are engaged in a process of experiential learning of collaboration while, in parallel, we follow up their interactions and collect communication data of interest. Lin2k collaboration evaluating and adaptive feedback mechanisms are aimed at equipping students with the necessary conceptual knowledge that underlies collaborative activity. Lin2k experimental uses in the Civil Engineering Department of Aristotle University of Thessaloniki, Greece, proved the efficacy of its pedagogy. The Lin2k educational process serves as a prototype that may contribute to the revision of engineering curricula so as to face the challenges that the new technologies impose, along with the necessity of relating academic to professional life.

Treated urban sewage sludge, which had been dewatered and dried in an open bed, was locally burnt in an open drum and bottom ashes were formed. This work investigated whether these bottom ashes of dried sludge cakes (SCbash)' produced by local labour and equipment, could be used as landfill covers or liners, a function normally served by clay. Laboratory tests were performed to determine the particle size distribution, Atterberg limits, compaction characteristics, hydraulic conductivity and shear strength parameters of the sludge cake. The effects of desiccation and freeze-thaw processes on the hydraulic conductivity of SCbash were also examined. It was found that properly compacted and stabilized SCbash has the requisite properties for use as landfill covers or liners. The SCbash can be compacted into a dense mass with a low hydraulic conductivity of the order of 1.15 X 10 -7 m s-1 (as a comparison, the hydraulic conductivity of compacted clay is around 10-9 m s-1). The compacted SCbash also showed good defence against the increases in hydraulic conductivity caused by desiccation and freeze-thaw processes compared with the data reported for compacted clays. The compacted SCbash also has a greater shear strength than is typically expected of compacted clay and therefore is likely to remain stable on a typical landfill slope design based on the shear strength of clay.

This paper presents the development of a 3D computational fluid dynamics (CFD) model of a covered deep anaerobic pond treating raw sewage. The model was based on an unsteady-state laminar flow which was solved in accordance with the finite volume method and simulated the hydrodynamic pattern and thermal energy balance of the anaerobic pond throughout a year of operation. The model input included hourly ambient air temperature, monthly soil temperature profile, daily influent wastewater temperature and velocity, which were incorporated through an external routine in C ++ . Numerical simulation was validated by temperature measurements from the experimental pond. The mean relative error and correlation factor out of 164 temperature values of the simulated pond, in comparison with the experimental one, was 9.34% and 0.91, respectively. The average temperature of the simulated pond throughout the experimental period was 18.9 • C. The validated 3D thermal model can be used as a tool for assessing and evaluating the impact of various design modifications (changes in construction material, adding insulation, installing a heat exchanger, etc.) on the thermal behaviour of an anaerobic pond, aiming at its average temperature increase which will, in turn, positively affect its organic removal performance. The thermal model presented, is the first stage of a complete anaerobic pond model which will include wastewater quality transport and basic biochemical reaction mechanisms of the anaerobic decomposition process present in an anaerobic pond. The complete anaerobic pond model will be able to predict the effluent COD of the pond.