Introduction

Intercropping stands for the cultivation of several crops on the same field. In this way, biodiversity can be increased, soil can be conserved and, with skillful planning and implementation, productivity can be increased.

In constructed wetlands, wastewater is passed through systems covered with plants and cleaned by the interaction of these plants in hydroponics with microorganisms, and by filtration through bio-based components (e.g., biochar or the soil). Constructed wetlands have several advantages; they can be operated with a minimum power input, have a simple and stable operation, are significantly less sensitive to fluctuations in wastewater generation and quality than conventional methods and are based only on natural materials and natural processes. They also serve as habitat and ecosystem, and can therefore contribute to an increase in biodiversity.

Biochar is produced by the pyrolysis of biomass (thermal treatment under limited oxygen supply). Biochar not only stores carbon for a longer period of time, but can also store water and minerals particularly well, thus serving to ameliorate the soil. It is therefore not surprising that biochar has been identified as on component of the famous Terra preta de índio.

Anaerobic fermentation (microbial conversion taking place in the absence of oxygen) of biomass produces biogas, a gas mixture consisting mainly of CO₂ and methane. This gas mixture can be burned directly to produce electricity and heat, or purified to natural gas quality and fed into the natural gas grid. It is a simple biological process that requires only microorganisms, water and heat.

After biogas production, part of the biomass remains as digestate, in which hardly digestible carbon-rich molecules and minerals accumulate, making it an attractive bio-based humus and mineral fertilizer.

Applying different treatment techniques certain bio-based products such as phenolics, oligosaccharides or fermentable sugars can be gained from biomass. In addition to obtaining bio-based products, the application of pre-treatment can additionally lead to higher yields in biogas production.