Technical aid by GAWI

The contribution deals with the origin and development of GAWI (German Aid Company for Developing Countries Ltd.) and its present activities in the field of technical aid of the Federal Republic of Germany

PHYTOREMEDIATION OF COPPER CONTAMINATED WASTE WATER USING LEMNA MINOR

The use of natural remediation methods to remove contaminants from waste water is becoming more popular. Plants have been used for several decades, yet their use for municipal waste water contaminated by heavy metals is limited to a few studies which focus on the Mercury and Chromium (Bennicelli, et.al, 2004). This study specifically attempted to determine the viability for using Lemna minor to remediate municipally generated wastewater contaminated with copper. The study used 100 ml samples of wastewater, artificially spiked with 8 mg/L of copper sulfate and seeded with approximately 100 Lemna minor fronds. Each treatment was repeated 15 times and distilled water was added daily to maintain 100 ml samples. The addition of Lemna minor statistically lowered the copper concentration of the treatment groups (55% reduction in total Cu concentration). No significant decrease was seen in the control groups. While Lemna minor has metals accumulation potential, its wide spread use is limited by the toxic effect of copper on Lemna minor at relatively low levels

Hydraulics of Minimum Energy Culverts and Bridge Waterways

The design of culverts and bridge waterways according to the approach described variously as "minimum energy" and as "constant energy" is summarised. The hydraulics of the flow in such waterways is discussed. Even though the flow occurring can be quite complex, the waterways can be designed with simple calculations within certain limitations. Some of these limitations are discussed. Some results concerning energy losses in the expanding part of the flow are presented

Introducing Originality and Innovation in Engineering Teaching: The Hydraulic Design of Culverts

Recently the teaching of engineering design has become a presentation of standards and codes rather than the learning of sound design practices. Too many students request formulae and equations to solve a design exercise and they fail to develop any design originality. The present student attitude leads to young graduate engineers without critical ability and innovative flair. The writer has developed an innovative hydraulic design exercise based upon culvert design. Each design exercise could lead to more than one correct design per student in the class. Students have to learn basic design calculations based upon lecture material, notes, field visits and laboratory experiment. The practical component (laboratory, field visit) contributes significantly to their understanding of the complete system, including some basic safety and professional issues