By: nkolola halwindi
9th November 2001
The development of integrated pollution-control and waste-management policies and strategies is, therefore, becoming a focal point for governments of developed and developing countries.
Many countries are in the process of evaluating technologies to ensure environmentally-sustainable waste disposal and management. It is for this reason that energy and environmental technology solutions company Amandla Environmental has launched the plasma converter from Startech, technology that converts hazardous and non-hazardous wastes of both organic and inorganic origin into safe, valuable commodities, such as plasma-converted gas.
The firm's director of operations, Andri Hugo, says that about 9,7-million tons of hazardous waste is generated a year in South Africa, adding that some 80 767 t of this is medical waste.
He reports that Gauteng has only one permitted landfill that can receive hazardous waste, forcing medical waste incinerators to operate at full capacity.
It is against this background and the need to introduce clean waste technologies that the firm, in a joint venture with Phambili waste services, a South African integrated waste-management company, proposes the plasma technology for waste-treatment and disposal at a site to be determined in Gauteng.
The technology, which was developed by Startech Environmental, is a pilot facility operating commercially in Connecticut, in the US, and is being commercialised throughout Africa and parts of Europe.
In a nutshell, the technology is a form of hazardous-waste treatment that can destroy a range of wastes, can take gaseous, liquid and solid waste simultaneously, and produce products from waste that can be used commercially, such as gas.
In addition to meeting the objective of recovering and recycling primary and secondary materials, the system is able to dispose of waste in a safe, environment-friendly manner that meets stringent international standards.
The gas produced can, depending on the waste stream, have a high carbon and hydrogen content, which can be used as a feed for chemical product manufacturing or as fuel for power generation or heating and cooling applications.
The initial catalyst is air, principally oxygen and nitrogen, that has been ionised so that it becomes an effective electrical conductor in plasma gas.
The technology is robust and automated, easy to use and operates quietly and safely at normal atmospheric pressure.
It uses an endothermic process to break waste down into its elemental form from which gas and other products are made, while, with conventional incineration methods, waste is reduced to hazardous bottom and fly ash, and potentially harmful air pollutants.
The gas can also be sold to gas users while the wastewater is treated before being discharged and any solids captured in the gas-polishing system can be reintroduced into the system for treatment. The technology can handle any waste stream, including municipal solid waste, medical waste, liquid effluent, abattoir waste, hazardous sludges and even low-level radioactive waste.
It thus reduces the volume of radioactive waste substantially, but does not render it non-radioactive.
The technology has been subjected to a general technical assessment as required by the Department of Water Affairs and Forestry for the proposed integrated waste management facility in Gauteng.
According to Hugo, the environmental-impact assessment (EIA) will evaluate the potential effects, both negative and positive, of the operation at a specific site to be selected in consultation with stakeholders and authorities.
Hugo says waste-management strategies of waste reduction, cleaner technologies, waste segregation and recycling should decrease the volume of waste in South Africa, adding that hazardous and medical waste will still be generated and will need to be handled and treated with no health or environmental risk.
"The introduction of an integrated waste-management facility that will handle hazardous and medical waste and meet environmental requirements provides a window of commercial opportunity for the application of the technology," says Hugo.
He reveals that the proposed 50 t/d plant will cost $9,5 million, with a total operational facility cost of $14 million.
The facility will be built and commissioned in the US, imported and installed as a unit, and the 250 m2 facility will consist of a laboratory, waste batching and storage, waste screening and shredding mechanism, water desalination plant, transformer and control rooms.
The project will create 22 permanent jobs and indirect employment will include transport, security and cleaning services.
Potential areas in Gauteng have been identified for the site.
Once stakeholders and authorities have agreed on the criteria to be used, all potential sites will be screened carefully by the study team.
The EIA will have three phases, with the scoping phase and impact assessment being the first, in which issues and concerns that need to be evaluated by specialist investigations are identified, and studies conducted to assess positive or negative effects.
The integration phase then follows, in which all issues raised and findings are integrated into a draft scoping report to obtain public comment.
Decisionmaking is the final phase, in which the Gauteng Department of Agriculture, Conservation, Environment and Land Affairs will make decisions and co-ordinate with other authorities to ensure that a consensus decision is reached.
Edited by: nkolola halwindi