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The key to landfill emissions control

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Environment

Dr Saeid Baroutian argues that we must put technology and innovation at the forefront if we are to find New Zealand-specific solutions for landfill gas capture

New Zealand must invest more in innovation and future technologies to meet the recommendations of the Climate Change Commission to increase the capture of landfill gas (LFG), the gas created from organic waste in decomposition.

Methane is the main component of LFG. It is a powerful greenhouse gas; it traps heat in the atmosphere and is much more aggressive than carbon dioxide. The warming power of methane means that the uncontrolled release of landfill gas into the atmosphere can create serious problems by contributing to global climate change, and, on a more local level, can cause fires and odors.

The recommendation to reduce waste and emissions from landfills and increase landfill gas capture was contained in the commission’s final report to government that was tabled in parliament last week.

The good news is that while landfilling is still one of the essential elements of an integrated solid waste management strategy, reduced waste emissions can be achieved through a balanced combination of waste management and waste management. landfill gas capture.

There are already different strategies available that can be used to increase the amount of methane captured. For example, installing new landfill gas capture systems in new or existing landfills and upgrading old landfill gas capture systems can minimize the uncontrolled release of landfill methane into the landfill. atmosphere. Many landfills in New Zealand have installed gas collection systems, but not all are effective.

We can also improve the efficiency of LNG production in landfills, increasing the amount of recoverable landfill gas over time while maintaining a relatively high level of methane concentration, which is crucial for conversion to energy. usable.

Innovations such as bioreactor landfills contribute to this strategy by using moisture to speed up the waste decomposition process, and additives to maximize landfill gas production. These processes increase the rate of waste decomposition which can be applied for energy recovery and emission reduction. For a local example of using innovation, resource recovery company EnviroNZ uses moisture adjustment and additive techniques at landfills, but so far there is no is no modern bioreactor landfill in New Zealand.

Adding value to landfill gas through upgrading so that it turns into a reliable energy source is another vital consideration. Crude LFG has a methane content (40-60%) and contains impurities and traces of gases such as hydrogen sulfide, siloxanes and other volatile organic compounds.

It has to go through a series of steps to be converted into Renewable Natural Gas (RNG), a high-quality fuel containing around 90% methane and suitable for use in power generation, industry , home and transport. For example, replacing the use of fossil diesel fuel in waste collection trucks with RNG can reduce transportation emissions in the waste management industry, leading the industry to net negative carbon intensity.

One of the main advantages of RNG is that it can be used in existing gas infrastructure. This makes it a cost effective option, especially for heavy duty industrial combustion and heating systems.

The calorific value of LFG is about half that of natural gas because it contains less methane. This means that the volume of LFG that has to be transported and handled by the burner is double that of natural gas. Upgrading from LFG to RNG will minimize net carbon emissions. Once compressed or liquefied, RNG can be used in natural gas vehicles without any modification to engines or fuel systems.

I would like to stress the role of research and innovation in reducing waste emissions. Technological innovation is increasingly seen as a key driver for reducing greenhouse gas emissions in developed countries. New Zealand should not be exempt. New Zealand’s climate change policy and investment should be coordinated with careful consideration of the role of research and technological innovation in reducing emissions. To be successful, efforts must catalyze scientific and technological expertise from industry, academia and government agencies.

EnviroNZ’s Energy and Resource Recovery Center at Hampton Downs, for example, has succeeded in maximizing gas extraction from residual waste and capturing it through an innovative approach. This is achieved through close research collaboration with the University of Auckland.

The New Zealand government can play an important role in this regard. For example, increasing funding intensity and subsidizing research and development (R&D) by private companies and supporting universities and research institutes can fill innovation gaps and reduce capital and investment risks. investment in new technologies. Independent academic research can also provide government and industry with access to data and knowledge and reduce the information gaps between the two.

Effective government enforcement of existing regulations will help ensure innovation and technology in the waste management and landfill sector. We cannot see significant improvements in reducing waste emissions if enforcement is relaxed. Additionally, new policies that encourage innovation and the development of advanced technologies can lead to breakthroughs that can transform New Zealand’s waste management industry.

The synergies between application, incentives and increased research and development will help shape the optimal technology solutions that work for New Zealand.



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