Looming landfill crisis faces SA’s largest metros

Besides being among our nation’s major metros, Johannesburg, Tshwane and Cape Town have something else in common – they all have less than 10 years of useful landfill life left.

Waste management is the least prioritised municipal service in most South African municipalities. It lags significantly behind housing, water, electricity and road infrastructure.

South Africa’s eight Category A metropolitan municipalities have the highest population numbers and therefore generate the largest waste volumes, at around 10-20 Mt (million tonnes) of waste a year each, of which the bulk is landfilled. Landfilling at an average density of 1 t/m 3 means that municipalities need an annual landfill space of about 10 million m 3 .

With this space at such a premium, the controlled, planned and systematic filling of

landfill cells requires progressive closure and rehabilitation. The recent fire at the New England Road landfill in Pietermaritzburg, KwaZulu-Natal, has raised awareness about the myriad issues facing the proper management of such sites throughout South Africa. Poorly managed landfill sites can cause numerous environmental issues – not only for natural resources but the social environment as well.

According to Elisabeth Nortje, associate director for Environment: Africa at AECOM, there are three areas of impact that need to be considered when thinking about poorly managed landfills – i.e. impacts on the biophysical, social and economic environments. “If you think about the biophysical environment, a poorly managed landfill can, for example, affect

groundwater, vegetation and biodiversity, among others. The impact on groundwater, specifically, has a knock-on effect on surface water, as well as the habitats and users that depend on that resource. Landfills also contribute significantly to emissions,” says Nortje.

Landfills are among the nation’s largest sources of methane – a greenhouse gas far more potent than carbon dioxide. When considering the social environment, Nortje notes that it may have an impact on human health.

According to a research study titled ‘Health and Environmental Risks of Residents Living Close to a Landfill: A Case Study of Thohoyandou Landfill, Limpopo Province, South Africa’, people living closer to landfill sites are at higher risk of suffering from medical conditions such as asthma, diarrhoea, stomach pain and a weak immune system.

An integrated approach

In terms of landfill assessments and management, infrastructure consulting firm AECOM has developed an integrated approach, which allows it to assist clients throughout the landfill life cycle – from site identification and landfill design through to rehabilitation and closure planning.

“An integrated management approach encompasses all three spheres I mentioned previously. It refers to a holistic approach to landfill management, which focuses on all aspects of the receiving environment. It would be of no value to focus only on one.”

Nortje stresses that an integrated approach will essentially extend the life of a landfill, help prevent pollution, and will help better serve the surrounding communities, among other benefits. It is only with proper planning and attention to duty of care that landfills can be developed and managed in a sustainable way.

Importance of regulation

A key component of landfill management is also regulatory. The regulatory aspect is critical, especially due to the large number of unlicensed landfill sites in South Africa.

It takes at least 9 to 12 months to obtain environmental approval, in addition to all the supporting specialist technical studies required. Therefore, the critical pathway of any landfill project is quite often the authorisation component.

“Many municipalities are really struggling to get this right. In addition, we also have so many unlicensed landfill sites. This is a historic problem, given that many are quite old and started operating well before the latest environmental legislation came into effect,” highlights Nortje.

Landfills may need to be closed for various reasons, including unacceptable environmental impacts such as groundwater pollution, and/ or unmanageable air pollution such as dust or odours. Geological issues include dolomitic ground conditions, which can result in water ingress and sinkhole formation. In many instances, improving landfill management and operations is a necessary first step, but if this proves unsuccessful, closure becomes necessary.

The process of landfill closure and remediation is legislated by the National Environmental Management: Waste Act (No. 59 of 2008), the Water Act (No. 36 of 1998) and the Waste Management Series.

While it might seem that the closure process only commences once the landfill has reached the end of its useful life, there are factors that need to be attended to while the site is still operational. The slopes of the waste body must be resolved to ensure they lie at a safe angle.

This should be maintained throughout the operational phase, after which capping is carried out by means of an engineered liner. Furthermore, all stormwater run-off must be diverted away from the waste body, separating the clean and dirty water circuits, and preventing leachate soaking into the waste body – which can result in subsequent groundwater pollution and odours. The site must also be fully secured and access-controlled to prevent trespassers.

For example, there could be an issue with people remining the waste body for recyclables, which presents a fire risk and allows rainwater to permeate the waste body. Following closure and remediation, the landfill site is subject to a recommended post-closure monitoring period of up to 30 years. This is to monitor the integrity of the capping and the impact of the quality of the groundwater in and around the waste body. There may also be a need for ongoing pumping and treatment of the leachate that gathers in the leachate collection system.

The landfill will also most likely require a methane management system, whether by landfill gas harvesting or regular flaring, preventing methane build-up, fire risk and air pollution.