Ground engineering and environmental consultancy group Golder Associates says waste management in South Africa, as in most developing countries, is heavily reliant on landfilling, with alternative waste treatment technologies, including recycling, anaerobic digestion, mechanical biologic treatment, mechanical heat treatment, energy from waste and in-vessel composting, being limited.
A number of landfill sites in South Africa, especially those around Gauteng, have limited space and, in several cases, pose significant potential health and safety hazards. Landfill sites are often at long haulage distances from service areas and depots and landfill gas contributes to greenhouse-gas emissions and landfill leachate pollutes nearby watercourses.
South Africa is heavily reliant on fossil fuels, namely coal, for energy and the country is experiencing energy supply restrictions, as its infrastructure is not capable of delivering as demand increases. However, the increasing demand for renewable-energy sources, energy efficiency and carbon dioxide emission reduction is driving the market for advanced waste treatment to unlock the economic potential of using waste as a sustainable energy resource.
Golder Associates waste management consultant Natalie Kohler says that the company focuses its consulting services on meeting the market demands for alternative waste treatment technologies. “Golder assists clients in developing additional waste processing and treatment infrastructure to minimise waste production and improve waste reuse and recycling initiatives, thereby providing a sustainable alternative to disposing waste at landfills.”
Advanced waste treatment processes are influenced by a number of factors, including political and socioeconomic drivers; availability of services and utilities; robustness and proven technologies; financial and affordability constraints; composition of the waste feedstock; and potential outlets for process products and residues.
Golder experts from Europe, where new methods of waste-to-energy projects are being developed, provide insight into these factors, as well as a practical record in the implementation of business intelligence for green sustainable waste management solutions. “Together with our global consultants, the South African team has worked on several significant local projects,” she says.
According to Kohler, Golder recently audited landfill gas-to-energy (LFGTE) proposals at nine landfills throughout South Africa. “We have seen significant differences in how LFGTE projects should be approached, both from an academic and a practical standpoint compared to Europe.”
LFGTE systems are a well-established means of securing renewable energy in Europe and North America, where the market is mature and landfill gas engineering is well understood and effective. In South Africa, however, it can be a different matter as the majority of existing operational landfills are, in part at least, unlined.
Although there are minimum requirements for active perimeter landfill gas and air quality monitoring, as well as the landfill engineering of new cells, a layered approach is used for landfill designs, rather than a cellular approach, providing long operational periods without capping.
Golder specialises in modelling the landfill gas resource recovery by using, for example, GasSim, which simulates the fate of landfill gas arising from managed or unmanaged landfill sites, as well as undertakes compre- hensive environmental compliance reviews. “We also offer technical design and construction management, assistance with project agreements and contracts, financial models, health and safety guidelines, as well as quality and operational reviews of the landfill sites,” says Kohler.
In another initiative, Golder has been appointed by a Gauteng provincial economic agency to assess the municipal and other waste characteristics of the province and the potential for recycling and waste-to-energy conversion. Gauteng is currently the most heavily populated province in South Africa, with a population of over 10.5-million people, and considered the economic hub of the country.
The ever-growing energy demand and increasing constraints on supply are significant risks to the growth and development of the Gauteng economy. Hence, the project includes an assessment of the mechanisms to deal with sustainable development through the efficient use of waste as a resource in the province.
This is undertaken to develop a green and environmentally sustainable economy by reducing the reliance on fossil-fuel-derived energy with a renewable form of energy.
Residual waste is a potential asset and resource from which energy and other residual products can be recovered, rather than being an environmental liability requiring collection and disposal to landfill. Waste-to-energy provides an alternative source of electricity, heat and steam, as well as a sustainable means of reducing reliance on the diminishing provincial landfill capacity.
Golder’s specialist studies included the opportunities that exist in terms of the characteristics of the waste streams in Gauteng and how these could be efficiently explored for downstream uses, such as waste to be gainfully used in new products, as well as concurrently promoting job opportunities.