In October 1998, the Department of Water Affairs and Forestry released the second edition of the Waste Management Series and in particular the document Minimum requirements for waste disposal by landfill. After four years of application, consideration and review of the first edition, the Department and industry were in a position to make several modifications to the documents, in particular the requirements with respect to landfill design. This article focuses on the implications that the changes in this document may have on the local geosynthetics industry.
Geosynthetics fulfilled various functions to ensure that the integrity of an internationally proclaimed wetland would not be compromised The DD5A Regional Outfall Sewer of the East Rand Water Care Company (ERWAT) traverses an area alongside the Blesbokspruit, an internationally proclaimed Ramsar wetland site. This article descriptionbes the use of geosynthetics, for tensile reinforcement during construction, as a geo-beam to prevent uplift and as an encirclement of a filter transport layer to facilitate identification of leakage in a post-construction monitoring programme. This latter action was deemed necessary as part of an Environmental Management Plan instigated by the client to ensure that the integrity of the environment would not be degraded owing to the location of a major sewer line over an environmentally sensitive area.
Since the first conference, the geosynthetics discipline has matured. We have seen the adoption of terms like geotextiles and geomembranes (coined by J P Giroud in 1977), then geonets, geogrids, geocomposites, geosynthetic clay liners and geofoam, encompassed by the generic term 'geosynthetics'. The conference in Atlanta was the first to be called simply the International Conference on Geosynthetics, signalling a maturity that fits with the passage of 21 years.
Ten years ago Con Roux, the founder and MD of civil engineering firm, Con Roux Ltd, decided that sustainable improvement in productivity was required to counter the continuing downturn in the construction industry. At that stage the firm, specialising in road-building, earthworks and township services, had been in operation for 22 years and employed some 800 people. The aid of the National Productivity Institute (NPI) was called in and a productivity improvement programme was drawn up.
The Employment Equity Bill 'Employment equity' is a new term for affirmative action. In essence, therefore, the objects of the Bill are to: Eradicate unfair discrimination; and Encourage employers to undertake organisational transformation that will remove barriers and accelerate training and the promotion of historically disadvantaged groups
Besides cement milling, storage and despatch facilities at PPC's existing clinker producing plant at Dwaalboom, the contract included a multicell storage silo with a combined lift-shaft/stairway tower. The multicell silo is configured to provide five storage cells for cementitious products within a single structure. A large area below the cone houses a loading facility and bag packing plant, with provision made for a second packer unit. The tower containing the lift-shaft and stairway adjacent to the silo gives access to working platforms below the inverted cone and carries services and cement-conveying pipelines to the top of the silo, from where the various products are distributed to the storage cells.
The use of bitumen in the stabilization of road base courses, though not entirely new elsewhere, is new to Southern Africa and has certainly not, to the Authors' knowledge, previously been used on a large scale.
The establishment of major industrial projects in South Africa, with their attendant engineering problems, offers great scope for the Civil Engineer but requires a new approach in respect of financial considerations. The paper covers one of the main civil engineering aspects involved in the recent construction of a dissolving pulp factory at Umkomaas, Natal. This was the provision of a 16.mgd purified water supply scheme. The history of the preliminary investigations and details of the alternative proposals leading up to the final choice of scheme are dealt with, followed by a descriptionption of the works which include a sand weir intake and purification plant. Details of operational difficulties are descriptionbed and the means of dealing with them discussed.