Two themes that have synergy and represent challenges for the new post-pandemic economic cycle are urban waste management and energy generation from biogas.
Biogas: Understanding the scenario
The increase in world consumption in the post-war period brought a great increase in the disposal of waste by consumers. “Urban waste”, which used to be organic waste, has been replaced by plastic packaging, growing alarmingly in volume.
Some societies understood the challenge of waste management and started production processes in which “recycle, reuse, reuse” were incorporated. The recognition of human action as the cause of the Global Warming problem also contributes to the implementation of this behavior.
Still, there are huge savings to be developed as, when collecting, much can be recycled/reused on an economic basis. This reduces logistical cost and reduces landfill volumes. After the disposal of waste, there is still much to be explored economically. One of the examples of short-term exploration is the generation of electricity from the biogas produced. The energy use of landfill biogas has become one of the priority topics for investment.
Biogas is the result of a series of biochemical reactions that degrade organic material in oxygen-free environments. It is a renewable and decentralized fuel, perfect for reducing Brazilian human emissions of greenhouse gases and more resistant to possible changes in normal weather patterns.
In relation to biogas from MSW (urban solid waste), its energy use can take place through two technologies:
- Sanitary landfills – All organic material in cities is deposited in landfills through closed cells. From there, through an oxygen-free system, it is transformed into biogas. Through a network of collector tubes, it is captured, treated and used to generate energy, the most common form being in internal combustion engines.
- Specialized Biodigesters – This is a technology still under development. In it, organic material is degraded in a controlled environment, generating biogas. However, unlike the sanitary landfill, here there is a previous sorting of the waste so that only the organic part is treated.
It is worth remembering that the RSU biogas is a decentralized renewable energy source, with use for various purposes. Among them is the generation of electricity, since when removing contaminants, it can be burned in engines for this purpose. Furthermore, when burned in ovens or boilers in its rawest state, it is capable of providing heat or lighting for homes, businesses or industries.
When refined, biogas turns into biomethane, which is similar to natural gas. In this way, it can be used in industrial processes and even as fuel for automobiles.
The world is undergoing important transformations in the area of energy. The so-called modern renewable energies, which include biofuels (including biogas), wind energy and solar energy, grow stronger year after year and show robust and accelerated growth, even in times of economic crisis.
Biogas: Source Challenges
In Brazil, however, there is still a challenge. This is because there is still no universalization of collection and adequate disposal of Solid Urban Waste (USW). The Diagnosis of Urban Solid Waste Management (SECRETARIA NATIONAL DE SANEAMENTO AMBIENTAL, 2016), showed that even though 98.6% of the urban population is served by the regular household collection service, only 52% of the waste is properly disposed of in landfills.
The country had its first experiences with the use of biogas in energy generation in the 1970s. However, even though they were promising, the initiatives were abandoned due to difficulties in controlling the biological processes of the installed biodigesters and to the corrosion of the equipment by the hydrogen sulphide.
At the beginning of 2000, due to the Kyoto Protocol, biogas returned to the surface due to the discussion around projects to reduce greenhouse gases in developing countries. However, the technology has not advanced much, as the resources for projects disappeared with the crash of carbon credit prices in the European EU-ETS market, the biggest in the world, in the years 2011/2012.
Currently, with the increase in electricity prices, the growing concern with exploring alternative sources and the professionalization of waste management companies, the debate on biogas is once again returning. However, an adequate infrastructure is still needed, capable of efficiently capturing, cleaning, combusting and refining it.
Source: Urban Solid Waste Energy Inventory, available here.