The high consumption of fossil fuels has significant environmental implications. An alternative to reduce the use of fossil fuels and develop ecological and economic processes is the bio-refinery approach. In the present study, the authors present the production of biodiesel from castor plants through a biorefinery approach. The process includes sub-processes associated with the integral use of castor plants, such as biodiesel production, oil extraction, fertilizer, and solid biomass production. Economic analyses show that producing only biodiesel is not feasible, but economic indicators (NPV, IRR, and profitability index) show it is much more feasible to establish businesses for the valorization of products and subproducts of castor plants, such as biomass densification. The internal rate return for the second scenario (E2) was 568%, whereas, for the first scenario (E1), it was not possible to obtain a return on investment.

Biopolymers can be derived from biological sources, including protein blends with plasticizers, starch, enzymatic synthesis, microorganisms, and algae. They are classified into polynucleotides, polysaccharides, and polypeptides, including polyhydroxyalkanoates, polylactic acid, and thermoplastic starch. Blending polymers with plasticizers and nanoparticles enhances their mechanical, thermal, and barrier properties. Biopolymers have various applications, such as in packaging, textiles, medical devices, cosmetics, agriculture, food products, emulsifiers, construction additives, bioplastics, and biofuels. Some of the advantages of biopolymers include their biodegradability, use of renewable resources, and reduced environmental impact. Nevertheless, certain disadvantages persist, such as high production costs, inadequate waste management systems, material quality loss during recycling, and the limited availability of raw materials. In this context, castor oil has emerged as a promising raw material for biopolymer production, with notable applications in coatings and sealants, and, consequently, bioplastics have become a sustainable and feasible alternative to conventional plastics that aligns with the principles of the circular economy. Moreover, new biopolymers are constantly being developed, and innovative applications are increasingly being explored across industries. The aim of the present review is to analyze the potential of biopolymers as sustainable alternatives to conventional plastics by evaluating their sources, production methods, advantages, limitations, and applications.

Untreated wastewater discharges into polluted bodies of water jeopardize the availability of water for human consumption. For that reason, constructed wetlands (CWs) are a sustainable and ecological technology commonly used in marginalized communities as an alternative wastewater treatment method, with low installation and maintenance costs. CWs use endemic vegetation for wastewater treatment, similarly to natural wetlands. Pollutants are removed from wastewater through biological, physical, or chemical processes. Additionally, CWs include deep wells, filter medium, and macrophytes. The radicular system of macrophytes decreases pollutant concentration by interacting with microorganisms associated with their roots. Macrophytes are especially important to CWs because they transport oxygen. For this reason, this review outlines the current state of CW technology and its operational challenges under extreme climate conditions, such as cold weather or winter. The operational conditions of CW systems are analyzed, mainly design modifications, macrophyte selection, and environmental conditions. The analysis is based on case studies and the background of CW systems installed in cold-climate regions or operating during the cold season. The review analysis was conducted using “Methodi Ordinatio”, which systematically analyzes the information with a specific purpose. Overall, CW systems operating in cold climates are an effective, sustainable, and adaptable technology for wastewater treatment. Effective modifications, such as design adaptations, plant species, and CW type, are essential to optimal operation and to maximize their efficiency.