Summary (En) | Gift

Rice production, despite its important role in food security, could bring about environmental problems such as methane emissions and polluting water resources. To decrease such negative environmental impacts, the co-culture of rice with ecologically friendly aquatic animals such as crabs has shown promising results. However, there are still serious concerns about the proper implementation of rice co-culture systems. Having considered rice-crab systems, crab stock density and the amount of crab feed, among others, are two important factors which regulate the performance of the system and the associated environmental pollution. However, their optimal values and their underlying relationship with enviro-economic parameters (e.g. methane emissions, nitrous oxide emissions, ammonia volatilization, yield, N uptake, nitrate in drainage water, and profit) have not been scrutinized yet. Accordingly, a set of farm experiments has been performed to measure enviro-economic parameters under mono- and co-cultivation of rice. Moreover, the attempts were made to explore the underlying correlations between crab stock density and the amount of crab feed as two independent variables and measured parameters such as yield and greenhouse gas emissions. Furthermore, an appropriate optimization model was developed to find the optimal crab density and crab feed in order to minimize the environmental pollution and maximize crab and rice yield as well as net profit. At the end, a farm survey was also conducted to evaluate the shortages in co-culture systems. The results showed that, under optimal rice-crab co-culture system, the improvements in nutrient uptakes ranged from 5.2% to 23.3%, with the lowest for Zn uptake and the highest for N uptake. Under such circumstances, 355% lower global warming impact would be attained compared to rice mono-culture showing a significant contribution to greenhouse gas mitigation. Furthermore, farmers would benefit from 122% higher profit under co-culture systems. The results achieved herein also have policy implications because it would help to decrease national greenhouse gas emissions and avoid deterioration of water resources while help farmers to ensure earning a high profit.

Au sommaire de cet article: intérêt d'une gestion globale de l'eau. Les usages de l'eau dasn les IAA. Caractéristiques des effluents des IAA. Audit préliminaire. Mise en place d'indicateurs. Connaissance des réseaux d'évacuation d'eau. Optimisation des circuits d'eaux propres. Production plus sobre. Optimisation des nettoyages. Prévention des pollutins accidentelles. Sensibilisation du personnel. Traitements ultérieurs

The food-energy-water (FEW) nexus is interconnected and interdependent and provides a physical foundation for mankind. The production of safe food, renewable energy, and clean water through biological means, especially microbial bioconversion, has attracted an enormous attention worldwide. Recently, in vitro synthetic enzymatic biosystems (ivSEBs) comprised of numerous enzymes and coenzymes, as a disruptive biomanufacturing platform, has been proposed and demonstrated to address key challenges at the interface of the FEW nexus. Light, electricity, and hydrogen can provide energy to fix CO2 and produce food and biomass. Lignocellulose-derived cellulose can be converted to starch and biofuels. Starch can be further converted to bioenergy, including electricity, hydrogen and liquid fuels. These high-energy efficient bioprocesses lead to significantly less water usage and also can be used to reduce water pollution. In this review, the conceptual framework and latest advances of ivSEBs in the FEW nexus are summarized. Their limitations and future research directions on the design and improvement of ivSEBs are also discussed.

Cet article est la synthese thematique d'une enquete menee en 1996 aupres de professionnels (industriels, fabricants et chercheurs) du nettoyage et de la desinfection dans les industries alimentaires sur le theme de la reduction de la consommation d'eau et de la production d'effluents polluonts, liee a ces operations. Dans cette optique, les produits chimiques recommandes sont les produits combines (detergent + desinfectant) encore trop peu utilises. L'utilisation de produits sous forme mousse ou gel permet aussi de reduire les quantites d'eau necessaires. Il semble interessant de generaliser les nettoyages prealables a sec (raclage, brossage avec aspiration, pousse a l'air comprime, etc...) permettant d'economiser de l'eau et des produits detergents, voire de recuperer de la matiere premiere. A l'inverse, les jets haute pression, tres repandus, sont a proscrire. Des efforts restent a faire (du point vue technique comme du point de vue de la mesure de leur efficacite) pour mettre au point et valider des methodes de desinfection plus "seches" (chimiques sans rincage, physiques a l'aide d'ultraviolets, d'ultra-sons ou de laser impulsionnel,...). Il apparait clairement que le nettoyage et la desinfection de surfaces non en contact avec les aliments demandent aussi une meilleure gestion de l'eau, et des etudes sur la necessite de certains rincages et desinfections sont fortement souhaitables. Enfin, des outils technologiques tels des capteurs pour le tri des flux ou des techniques separatives permettront de rationnaliser les consommations, de recycler l'eau et les produits (en particulier dans les systemes de nettoyage en place) et de reduire les rejets provoques par les operations de nettoyage et de desinfection