December 1, 2023 | Current Opinion In Green And Sustainable Chemistry | Source |
Introduction: Insects, particularly the Black Soldier Fly (BSF), offer a promising solution for recycling nitrogen from biowaste. BSF larvae efficiently convert waste into protein-rich biomass and nutrient-rich residue, which can be used as animal feed and fertilizer. This process reduces waste, lessens the need for synthetic fertilizers, and provides an alternative protein source. Research team based in Thomas More University College in Belgium conducts a literature review on the efficiency of this nitrogen conversion, as well as managing emissions like ammonia (NH3) and nitrous oxide (N2O) for enhancing sustainability in waste management.
Key findings: Efficiency varies depending on the type of waste and its carbon-to-nitrogen (C/N) ratio. For example, mixing different waste types to balance the C/N ratio can improve nitrogen conversion efficiency. However, too much nitrogen or imbalanced ratios can reduce efficiency and larval growth. Additionally, during BSF treatment, nitrogen can be lost as gases like NH3 and N2O, which can negatively impact the environment. Studies reveal that emissions depend on factors like waste composition and moisture content. High moisture can increase NH3 emissions, while a balanced C/N ratio can help reduce these losses.
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Figure | The nitrogen cycle. The nitrogen cycle comprises of several complex biological process that describes the transformation of nitrogen in various forms and its cycling through ecosystems. The major steps of the nitrogen cycle are as follows: Nitrogen fixation: dinitrogen gas (N2) is fixed from the atmosphere into ammonium (NH4+) or ammonia (NH3) by nitrogen fixing bacteria. Nitrification: nitrification is an aerobic process that occurs by nitrifying bacteria in two steps: nitritation, the oxidation of ammonia to nitrite (NO2-), and nitratation, oxidation of nitrite to nitrate (NO3-). Dissimilatory reduction (DNRA): Dissimilatory reduction of nitrite to ammonium. This process is carried out by certain bacteria and fungi under anaerobic conditions. Anammox (anaerobic ammonia oxidation): ammonium and nitrite are converted into nitrogen gas under anaerobic conditions. Assimilation: Plants and microorganisms take up the nitrate and ammonia from the soil to use as building blocks for proteins, nucleic acids and other organic compounds. Mineralization: decomposers such as fungi and bacteria break down organic matter into simpler compounds, releasing ammonia back into the soil. Denitrifiaction: in this anaerobic process nitrate and nitrite are reduced to gaseous forms of nitrogen, principally nitrous oxide (N2O) and nitrogen.
