Biowaste treatment through industrial insect farms: One bioeconomy puzzle piece towards a sustainable net-zero carbon economy?

Abstract

Global methane emissions have moved in the last years into the focus of the Climate Change scientific community because of continuing increases of global methane emissions and their contribution to global warming. In 2019, methane emissions reached 260% of the pre-industrial level (WMO, 2020). There exists scientific consensus that due to its high short-term global warming potential, which is about 25 times higher than the warming potential of carbon dioxide (C2ES, 2021), without the substantial reduction of methane emissions the Climate Targets of the Paris Agreement (UNFCCC, 2015), cannot be met. In addition to methane emissions from the fossil energy sector, a large share of methane in the atmosphere has its origin in agriculture and improper organic waste management strategies associated with landfilling of organic waste. This is especially true in developing nations in the subtropical and tropical regions where organic waste separation and landfill gas emission controls are still an exception and where the share of organics in household wastes can exceed 60%. To reach their climate protection pledges, as part of the Paris Agreement (UNFCCC, 2015), methane emission reductions could play a crucial role for developing nations because of the high share of untreated organic waste and their typically dominant agricultural sector. Thus, the inclusion of methane emission reduction strategies in their nationally determined contributions (NDCs), which have to be updated every 5 years by the Paris Agreement member countries, could be a powerful lever for developing nations to reach their short-term climate mitigation goals. Perhaps a seemingly separate trend presents an interesting opportunity in this regard. The production of insect protein in industrial insect farms is gaining ground in different parts of the world and might be an effective approach to address negative climate impacts in various ways by combining sound management of biowaste while also producing protein for food and feed. Although this approach could reduce methane emissions from improper biowaste management, it allows for positive climate impacts in the agricultural sector, and it may reduce the need to produce protein from other more traditional and possibly more energy intensive alternatives, such as for example soy bean sources. Finally, a highquality organic fertilizer can be produced as well. Technological progress in plant automatization and waste separation technologies have made it feasible to implement large-scale insect farms, which can process several hundred tonnes of organic waste per day and transform it in three main products for which there are established markets. These are insect protein, insect oil and the frass product, a high-quality organic fertilizer. This technology has several advantages compared to traditional organic waste treatment strategies and could make a very meaningful contribution to meet several of the UN Sustainable Development Goals (SDGs) for the year 2030 and thereafter (UN, 2015). This contribution goes beyond the climate change mitigation effect and also includes SDGs, such as reduction of hunger, maintaining potable water quality, improving sanitation, responsible consumption and production and others. Industrial insect farms can be consumers of organic wastes diverted from landfills while providing an organic fertilizer at the end, thereby helping to close the circularity gap of traditional organic waste management because nutrients are recycled and returned through the agricultural process. Insect protein produced from organic waste streams therefore are seen as the missing link of a circularity-oriented food system. Diversion of organics from landfills will reduce both methane emissions and the leaching of organic chemicals into groundwater. Although various waste streams – mainly food waste and agricultural residues from food and feed production – are already processed in insect farms, the application of this technologies for other waste streams, such as fine fraction from municipal solid waste (MSW) resulting from mechanical treatment of MSW, still needs to be investigated and developed to prove a sound implementation of this innovative approach in the waste management sector. Clean single-source waste streams have the advantage that they require less feed-preparation technology, for example cleaning of the waste before it enters the insect farm as a feed substrate for the insect larvae, but they have the disadvantage that these sources frequently are already used for alternative applications, as for example animal feed, biogas plants or compost plants. The huge still mostly untouched source as feedstock for insect farms lies in the organic fraction of MSW. Innovative waste separation technologies, like for example bio-separators, enable the cost-effective extraction of the organic fraction from MSW and with a high degree of purity, making it suitable to use as feedstock in industrial insect farms. The produced insect protein and insect oil are high-valued commodities, which can be sold locally or internationally. This makes the value creation more independent of local market conditions as it is the case for traditional compost production or energy production via biogas plants. The main markets for the final products are as animal feed for agriculture, aquaculture, poultry production or as feed for pets. As the sector feed by far is the biggest consumer of biomass available on a global scale (approx. 60%) (Umweltbundesamt, 2013), especially the use of insect protein produced from biomass in waste for feed purposes could be an important element of the transformation to bioeconomy. Human consumption of insect-based protein is practiced in some parts of the world, but the other markets for such protein is sufficient to preclude the need to expand sales into grocery stores. By making a contribution to the global protein market, the production of insect Biowaste treatment through industrial insect farms: One bioeconomy puzzle piece towards a sustainable net-zero carbon economy? 1036949WMR0010.1177/0734242X211036949Waste Management & ResearchEditorial editorial2021