Use of duckweed, bentonite and acid to improve water quality of effluent discharge from abattoirs

Intensive animal industries create large volumes of nutrient rich effluent, which, if untreated, has the potential for substantial environmental degradation. Aquatic plants in aerobic lagoon systems have the potential to achieve inexpensive and efficient remediation of effluent, and to recover valuable nutrients that would otherwise be lost. Members of the family Lemnaceae (duckweeds) are widely used in lagoon systems, but despite their widespread use in the cleansing of sewage, only limited research has been conducted into their growth in highly eutrophic media, and little has been done to systematically distinguish between different types of media. This study examined the growth characteristics of duckweed in abattoir effluent, and explored possible ways of ameliorating the inhibitory factors to growth on this medium. A series of pot trials was conducted to test the tolerance of duckweed to abattoir effluent partially remediated by a sojourn in anaerobic fermentation ponds, both in its unmodified form, and after the addition of acid to manipulate pH, and the addition of bentonite. Unmodified abattoir effluent was highly toxic to duckweed, although duckweed remained viable and grew sub optimally in media with total ammonia nitrogen (TAN) concentrations of up to 100 mg/l. Duckweed also grew vigorously in effluent diluted 1:4 v/v, containing 56 mg TAN/L and also modified by addition of acid to decrease pH to 7 and by adding bentonite (0.5%).

An innovative use of the web to build graduate team skills

Successful graduates in today's competitive business environments must possess sound interpersonal skills and the ability to work effectively in team situations within, and across, disciplines. However, developing these skills within the higher education curriculum is fraught with organisational and pedagogical difficulties, with many teachers not having the skills, time or resources to facilitate productive group processes. Furthermore, many students find their teamwork experiences frustrating, demanding, conflict-ridden and unproductive. This paper brings together the perspectives and experiences of an engineer and a social scientist in a cross-disciplinary examination of the characteristics of effective teamwork skills and processes. A focus is the development and operation of 'TeamWorker', an innovative online system that helps students and staff manage their team activities and assessment. TeamWorker was created to enhance team teaching and learning processes and outcomes including team creation, administration, development and evaluation. Importantly, TeamWorker can facilitate the early identification of problematic group dynamics, thereby enabling early intervention.