COVID-19 crisis interlinkage with past pandemics and their effects on food security.

BACKGROUND: Pandemics as health and humanitarian crises have exerted traceable impacts on food security. Almost all past and current pandemics have created a food crisis that affects a share of the global population and threaten global food security. With the more frequent outbreaks of emerging and re-emerging diseases or pandemics, this paper looks at the various types of impacts from the current coronavirus crisis and past pandemics to identify their major impact on food security. SCOPE: To this effect, key strategies that could be put in place to ensure the efficient resilience of food systems before, during, and after the pandemics to mitigate the negative impact of the pandemics on global food security are recommended. The most recent effects of the current coronavirus crisis have been disruptions in the flow of farm labourers and inefficient farm operations leading to postharvest food losses. KEY FINDINGS AND CONCLUSIONS: Modification of diets between social groups has also been observed. Future response orientations to prevent and mitigate the effects of pandemics on food security will consider pro-active and adapted policy, program, and institutional actions towards the systemic development of global food systems as an interconnected network.

Nitrification in a completely stirred tank reactor treating the liquid phase of digestate: The way towards rational use of nitrogen.

The nitrification of the liquid phase of digestate (LPD) was conducted using a 5L completely stirred tank reactor (CSTR) in two independent periods (P1 - without pH control; P2 - with pH control). The possibility of minimizing nitrogen losses during the application of LPD to the soil as well as during long-term storage or thermal thickening of LPD using nitrification was discussed. Moreover, the feasibility of applying the nitrification of LPD to the production of electron acceptors for biological desulfurization of biogas was assessed. Despite an extremely high average concentration of ammonia and COD in LPD reaching 2470 and 9080mg/L, respectively, nitrification was confirmed immediately after the start-up of the CSTR. N-NO3- concentration reached 250mg/L only two days after the start of P1. On the other hand, P1 demonstrated that working without pH control is a risk because of the free nitrous acid (FNA) inhibition towards nitrite oxidizing bacteria (NOB) resulting in massive nitrite accumulation. Up to 30.9mg/L of FNA was present in the reactor during P1, where the NOB started to be inhibited even at 0.15mg/L of FNA. During P2, the control of pH at 7.0 resulted in nitrogen oxidation efficiency reaching 98.3±1.5% and the presence of N-NO3- among oxidized nitrogen 99.6±0.4%. The representation of volatile free ammonia within total nitrogen was reduced more than 1000 times comparing with raw LPD under these conditions. Thus, optimum characteristics of the tested system from the point of view of minimizing the nitrogen losses as well as production of electron acceptors for the desulfurization of biogas were gained in this phase of reactor operation. Based on the results of the experiments, potential improvements and modifications of the tested system were suggested.