Due to climate change, two-thirds of mankind will face water scarcity by 2025, while by 2050, global food production must increase by at least 50% to feed 9 billion people. To overcome water scarcity, 15 million m3/day of untreated wastewater is used globally for crop irrigation, polluting the soil with pathogens, heavy metals and excess salts. Since 10% of the global population consumes food from crops irrigated with wastewater, pathogens transmitted through the food chain cause diseases especially in young children and women. In this paper, we discuss the status of water scarcity and the challenges to food security, the reuse of wastewater in agriculture and the possible risks to human and environmental health. The efficiency of different irrigation systems in limiting the risks of wastewater reuse and the latest regulations of the European Commission on effluent recovery are also presented. Hence, we emphasize that irrigation offers real perspectives for large-scale recovery of wastewater, helping to reduce the deficit and conserve water resources, and increasing food safety, with the express mention that investments must be made in wastewater treatment plants and wastewater must be properly treated before recovery, to limit the risks on human health and the environment.

Seeking to become more climate-friendly and less energy-consuming, the European Union has pledged to cut its greenhouse gas emissions and milestones to achieve this are set to 20 % by 2020, 40 % by 2030, 60 % by 2040 and 80 % by 2050. Due to its abundance, biomass is gaining more and more importance both for the production of thermal energy by direct combustion or gasification of vegetal materials, for electricity and for the production of biofuels. Direct combustion of biomass generates CO 2 , but the process is neutral in terms of greenhouse gas emissions, because the same amount of CO 2 was absorbed by plants from the air during their life cycle. Ecological solid fuels such as pellets have become rapidly a viable alternative to fossil fuels, due to their high energy content, which makes them suitable for use by both small households and industrial consumers. Pellets are obtained from a variety of raw materials such as: agricultural residues, energy crops, forestry and wood residues, used exclusively or mixed and having different physical-chemical properties. This paper presents a summary of literature on the effect of the moisture content on the properties of pellets obtained from various types of biomass. Moisture content of raw material is one of the most important factors that influence negatively the properties of pellets, such as bulk density or mechanical durability during storage and transportation. Energy consumption increases during pelletizing of high moisture biomass, as moisture is a lubricant that lowers friction in the die. Other studies found a positive correlation between pellets durability and optimal moisture (10 %), because water together with the die temperature, pressure and chemical composition of raw material acts like a binding agent that increases pellet quality. Pellets with 5 % moisture have low strength, become brittle, and large amounts of dust are produced during their storage and transportation. Moisture higher than 15 % damages pellets during storage.

It is very important to determine mechanical damage quantity of fruit and vegetables during harvesting, handling, transportation, and storage. Specifically, determining damage quantity of agricultural products is very difficult on existing external forces. However, one of the useful methods is the finite elements method that can be used in different engineering disciplines to simulate the behavior of materials under the defined boundary conditions. In this study, a drop-test simulation was performed for peach samples by means of finite elements method. Some mechanical properties of the sample were measured by an experimental study (compressive test) and the obtained data were used in the finite elements method simulation. The stress-strain and force-deformation curve of peaches were determined as maximum force, Poisson's ratio, specific deformation, modulus of elasticity, stress, and deformation energy were found to be: 59.6 N, 0.29, 10.9%, 0.89 Nmm-2 , 1.19 Nmm-2 , and 162.2 Nmm, respectively. At the end, the distribution of stress and shape of deformation of sample peaches at impact was obtained. When the stress magnitudes were evaluated, simulation outputs showed that simulation stress values are quite a bit compatible with experimental data.

Sugarcane is a lignocellulosic crop and the juice extracted from its stalks provides the raw material for 86% of sugar production. Globally, sugarcane processing to obtain sugar and/or ethanol generates more than 279 million tons of solid and liquid waste annually, as well as by-products; namely, straws, bagasse, press mud, wastewater, ash from bagasse incineration, vinasse from ethanol distillation, and molasses. If not properly managed, this waste will pose risks to both environmental factors and human health. Lately, valorization of waste has gained momentum, having an important contribution to the fulfillment of policies and objectives related to sustainable development and circular bioeconomy. Various technologies are well-established and implemented for the valorization of waste and by-products from sugarcane processing, while other innovative technologies are still in the research and development stage, with encouraging prospects. We propose a sustainable sugarcane processing flow and present an analysis of the physico-chemical characteristics of generated wastes and by-products. We emphasize the available possibilities of valorizing each waste and by-product, considering that they are important biomass resources for obtaining biofuels and a wide range of other products with added value, which will contribute to the sustainability of the environment, agriculture, and human health worldwide.

Inadequate production practices are widely used in aquaculture management, causing excessive water and energy usage, as well as ecological damage. New approaches to sustainable aquaculture attempt to increase production efficiency, while reducing the quantities generated of wastewater and sludge. The sustainable operating techniques are often ineffective, expensive, and difficult to implement. The present article proposes a zero-waste production system, designed for growing fish and vegetables, using a new circular operational concept that creates synergies between fish farming and horticulture. In order to optimize the operational flows with resources, products, and wastes in an integrated zero-waste food production cluster, a business model was designed associating three ecological production practices: a closed fishing pond, a technology for growing vegetables in straw bales, and a composting system. The design had the role to assist the transition toward multiple circular material flows, where the waste can be fully reintegrated into the production processes. A comparative evaluation was conducted in three alternative growing environments, namely, a soilless culture established in straw bales, a culture grown in soil that had received compost fertilizer, and the conventional farming technique. When compared to conventional methods, experiments showed a significant increase in the cluster’s cumulative productivity, resulting in a 12% improvement in energy efficiency, 18% increase in food production, and 25% decrease in operating expenses.

Rotary seed sorters used for wheat processing show some functional advantages in eliminating persistent contaminants, especially due to the more aggressive treatment applied to the processed material. The objective of this paper was to design a new constructive subassembly that would increase the performance of rotary sorters used for extracting various contaminants from seeds. By testing a pilot stand that reproduces the operation of a professional equipment and developing mathematical models that fits the main operating parameters, it was possible to identify the new characteristics needed to improve cylindrical sieves and to optimize the functioning of this equipment.

The paper presents experimental results obtained in the study of heavy metals transfer from soil to vegetables. The experiments for which the raw and statistically processed data are presented in this paper are preliminary experiments within an extensive research program of plant behaviour in soils contaminated with heavy metals. These experiments underlie the development of primary statistical mathematical models that are also presented in the paper. These experiments will also form the basis for far more consistent experiments that follow plants throughout the life cycle. The statistical mathematical models presented in this paper facilitate extracting important conclusions about how plants accumulate heavy metals as well as about the accumulation rate behaviour during experiments. Both experiments and mathematical models will form the basis of complex experiments and dynamic mathematical models in the next stage of research.

To accurately predict the impact of various species of plants on environment is a very difficult task, because their characteristics and specificities together with the external conditions of climate and fauna lead to very complicated systems that are difficult to analyze. The paper aims to assess two technical plants that may be used for the production of biofuels, namely Jerusalem artichoke and Sweet sorghum in evaluating fuel production efficiency and the possibility of being regarded as a viable solution for ecosystem conservation.