Abstract: This devise addresses the inadequacies of providing a quick means of holding jobs of
irregular shapes such as are encountered in small scale fabrication workshops. The conventional
bench vise often does not provide the adequate grip for such shapes so that attachments in the form
of V blocks are usually provided to enhance the grip before drilling operations are carried out. This
versatile work holding device enables fabricators to perform drilling and other production operations
on a work piece. This device produced from mild steel plates uses the toggle principle to provide
rapid grip. Comparative tests on time span in the use of this device and the bench vice for job set up,
production operation and then disassembly showed that time is gained with use of the device.
Abstract: The distribution of heavy metals in leachates from a waste dumpsite was investigated.
Soil samples were taken from a major dumpsite in Edo State located at Oluku near the National
Institute for Oil Palm Research (NIFOR) and analyzed. The heavy metals considered were Iron,
Lead, Zinc, Mercury, Chromium, Cadmium, Arsenic, Nickel, and Copper. The concentrations, in
mg/l, of these heavy metals in the leachates from the soil samples over a distance of 80 meters were
determined using the Atomic Absorption Spectrophotometer (AAS). The following results were
obtained, the concentration of Iron ranged between 1.25-1.85 mg/l, Chromium: 0.01-0.07 mg/l,
Zinc: 0.45-3.45 mg/l, Copper: 0.01-0.03 mg/l, Lead, Mercury, Cadmium, Arsenic, and Nickel had
negligible values, i.e. less than 0.01 mg/l. From the results the concentrations of iron and zinc fell
within Federal Environmental Protection Agency (FEPA) limits.
Abstract: Plastic carrier bags have gained popularity with Zimbabwean shoppers since they
provide convenient carriage of groceries and related goods. However most of these have a short
useful life and are often disposed into landfills or littered. This research was aimed at assessing the
interaction between the High Density Polyethylene (HDPE) plastic carrier bag life cycle and the
environment, hence identifying specific life cycle stages that pose significant threats to the
environment. The study was conducted in accordance with the ISO 14040 based Life Cycle
Assessment (LCA) methodology. The life cycle stages assessed include the extraction of HDPE,
transportation of HDPE pellets, production of the bags, transportation of the finished goods to
retailers and disposal scenarios. Improvement strategies were then identified to optimise the
environmental performance of the plastic carrier bags.
Abstract: Estimates of weight of general refuse generated in this country’s major cities vary, but in
Harare it is estimated at above 823 000 tonnes, which is mostly land-filled. This paper proposes the
incineration of combustible municipal waste to produce 40 MW of electricity and considers its
feasibility. This can give a waste reduction to as low as one tenth of the initial volume and is quite
effective in killing pathogens. The work involved use of questionnaires, interviews and access to
primary data at the Harare City Council. The positive and negative environmental and health
impacts, particularly relating to dioxins are discussed and solutions to pollution proposed.
Abstract: In this work, a comparative study of biogas production from poultry droppings, cattle
dung, kitchen waste, fruit waste and vegetable waste was done under the same operating conditions.
3kg of each waste was mixed with 9kg of water and loaded into the 5 constructed digesters. Biogas
production was measured using water displacement method for a period of 40 days and at an
average temperature of 30.5oC.
Results indicated that poultry droppings produced 0.0332dm3/day, cow dung produced
0.0238dm3/day, Kitchen waste produced 0.0080dm3/day, vegetable waste produced 0.0066dm3/day
and fruit waste with 0.0022dm3/day. It is concluded that poultry droppings produced more biogas
because it contains more nutrients and nitrogen compared with plant and other animal waste
Abstract: The search for alternative sources of energy from organic waste has been on in Nigeria.
This report focuses on a simple design, fabrication and performance test of a prototype biogas
digester. The volume of the digester was 340dm3 and that of the absorber/adsorber was 12.5dm3. The
digester was fabricated using mild and stainless steels, styrofoam, polythene sheets and other
materials. The digester can be moved about and agitated manually. In the performance test, 8.134L of
biogas was generated within 14 days of anaerobic digestion of palm oil mill effluent (POME). The
optimum pH and temperature for biogas production were 6.2 and 29oC respectively.