South African hazardous-waste landfill sites have a new best-practice champion in multinational waste-management company Averda’s R250-million Vlakfontein high-hazardous-class landfill site, in the Vaal Triangle.
It is the first landfill site of its kind in South Africa to comply with the new Waste Classification and Management regulations, which came into effect in August 2013.
It is also the first landfill site to be constructed to the standards prescribed by the Waste Classification and Management regulations for Class A containment barriers, and the first high-hazard landfill site to be developed locally in 20 years.
Earthworks at the landfill site were limited, owing to the site being a former brickmaking quarry operated by Vlakfontein Bricks.
Vlakfontein’s effectiveness comes from its design and barrier technology, which prevents hazardous materials from entering the environment.
The barrier, or liner, comprises a 1.2-m-deep multilayered solution of compacted clay, high-density polyethylene, stone and geotextiles.
The solution is designed to not only prevent harmful waste from seeping into the soil but also drain and capture environmentally harmful liquids, known as leachate.
Averda logistics head Brent Mahoney notes that the new regulations stipulate what materials are banned from landfill and promote best-practice treatment and blending ratios for neutralising agents into waste materials.
Leachate from Vlakfontein’s 500 000 m3 Cell 1 site, which started accepting waste in May this year, is gravity-fed into two 5 000 ℓ tanks. Once the tanks reach capacity, the leachate is pumped up to the leachate dam.
Vlakfontein will have six cells providing 6 500 000 m3 of landfill capacity. The cells will be constructed in a phased approach, according to the rate at which preceding cells are filled. The site has a 30-year life span.
Mahoney explains that leachate in the dam will be treated at a purification plant, which will be constructed once there is sufficient leachate, to remove any hazardous material. Once treated, the leachate will be of sewage discharge quality.
Mahoney adds that, by capturing leachate in tanks and pumping it to the dam, Vlakfontein can also prevent the leachate from contaminating rainwater captured on site. This allows for the rainwater to be used for other applications, such as dust suppression.
Companies disposing of waste are required to classify the waste streams in accordance with SANS 10234 before disposal, in compliance with the requirements of the Waste Classification and Management regulations.
SANS 10234 complies with the Globally Harmonized System, the international standards for chemicals classification and labelling.
Once a waste stream has been classified, a certificate is issued stating that it is safe for disposal at a hazardous-waste-to-landfill site.
Averda technical manager Neville Chetty explains that the classification and assessment processes enable landfill sites to determine the inherent hazards of the waste, such as the flammability or toxicity of the material, and the risks associated with the disposal of the waste to landfill.
When the waste arrives at the landfill, it is verified to ensure that there are no deviations in its composition – Vlakfontein has its own laboratory facilities on site and can provide verification within 15 minutes.
Following verification, the waste is taken to the cell for treatment and disposal.
Averda MD Johan van den Berg adds that the company can provide classification services for companies looking to dump waste at Vlakfontein with the baseline analyses facilitated through a third-party laboratory.
Averda Vlakfontein operations manager Fanie Pieterse explains that, for the landfill to be able to accept hazardous waste, a waste barrier of at least 3 m high is necessary to ensure that the material does not reach the barrier.
The barrier is designed with a leak-detection system, which captures leachate in the area should a leak occur, providing a visual cue of the leak, as well as information on where repair work to the liner needs to be done.
With about 7 000 km of barrier lining, this is particularly important, as detecting the location of a leak allows for cost-effective maintenance, rather than having to replace the entire liner.
Vlakfontein received its first hazardous waste stream – asbestos – in August. The site required about 7 000 t of general waste ahead of accepting the hazardous material. This was to ensure that there was enough of a buffer between the hazardous waste and the barrier, which could be damaged by corrosive material.
Prior to leaving a hazardous landfill site, dump trucks have to be washed to prevent harmful materials from leaving the site. Thus, Averda installed a truck- and wheel cleaning system at Vlakfontein. The R1.25-million system was imported from the UK.
According to Van den Berg, the purpose of the landfill site must be clear from the outset to ensure licences are received from the competent authorities, the Department of Water and Sanitation and the Department of Environmental Affairs (DEA).
“This purpose needs to be focused, as it determines the type of waste to be processed, as well as the estimated volumes and expected life cycle of the site,” he says, noting that these are important requirements in terms of the Waste Classification and Management regulations when applying for a landfill licence.
Van den Berg highlights that site selection must strike a balance between the environmental and social impacts and the suitability of the location.
“Selecting a site is one of the most important routes to establishing a landfill facility,” he says, adding that social- and environmental-impact assessments need to be done in conjunction with thorough consultation with local municipalities and any other affected stakeholders.
“This allows for a better understanding of future development plans for the city, what communities need and how businesses will benefit, which, in turn, guide the possibilities for expanding or winding down the facility, if needed. Transport routes and logistics also need to be considered, alongside environmental concerns.”
When developing a landfill site, all related costs also need to be mapped out, including development, construction and maintenance costs.
“The landfill operator needs to consider the long-term building, management and rehabilitation costs of the project, along with the revenue projection. It is vital that contingency costs are also factored in to anticipate changes in the regulatory, economic and social environment,” Van den Berg posits.
He notes that landfill operators must ensure that the facility is “adequately equipped with the correct containment barriers in line with DEA specifications for each class of landfill”.
Further, waste needs to be thoroughly assessed before entering the facility and it is the responsibility of the operator to ensure that the correct waste enters the site. This can be achieved by conducting assessments through a third-party laboratory to identify the chemical composition of waste material.
“Certain types of waste, such as explosive, flammable and corrosive materials, are prohibited from being disposed of at South African landfills,” Van den Berg highlights, adding that restricted materials must be disposed of in line with the processes governed by the Waste Classification and Management regulations.
Different types of waste should be treated using only the latest and best technology and processes available to the waste-management industry, he adds.
“Ticking these important compliance boxes will mean a successful landfill site that serves and protects society, and manages waste efficiently,” Van den Berg concludes.