Suchergebnisse

AbstractThis literature review outlines the most important—agricultural and non-agricultural—types of sewage sludge management. The potential of waste sludge protein hydrolysates obtained by chemical sludge conditioning was reported. The discussed areas include acidic and alkaline hydrolysis, lime conditioning, polyelectrolyte dewatering and other supporting techniques such as ultrasounds, microwave or thermal methods. The legislative aspects related to the indication of the development method and admission to various applications based on specified criteria were discussed. Particular attention was devoted to the legally regulated content of toxic elements: cadmium, lead, nickel, mercury, chromium and microelements that may be toxic: copper and zinc. Various methods of extracting valuable proteins from sewage sludge have been proposed: chemical, physical and enzymatic. While developing the process concept, you need to consider extraction efficiency (time, temperature, humidity, pH), drainage efficiency of post-extraction residues and directions of their management. The final process optimization is crucial. Despite the development of assumptions for various technologies, excess sewage sludge remains a big problem for sewage treatment plants. The high costs of enzymatic hydrolysis, thermal hydrolysis and ultrasonic methods and the need for a neutralizing agent in acid solubilization limit the rapid implementation of these processes in industrial practice.
Graphical abstract

This literature review outlines the most important—agricultural and non-agricultural—types of sewage sludge management. The potential of waste sludge protein hydrolysates obtained by chemical sludge conditioning was reported. The discussed areas include acidic and alkaline hydrolysis, lime conditioning, polyelectrolyte dewatering and other supporting techniques such as ultrasounds, microwave or thermal methods. The legislative aspects related to the indication of the development method and admission to various applications based on specified criteria were discussed. Particular attention was devoted to the legally regulated content of toxic elements: cadmium, lead, nickel, mercury, chromium and microelements that may be toxic: copper and zinc. Various methods of extracting valuable proteins from sewage sludge have been proposed: chemical, physical and enzymatic. While developing the process concept, you need to consider extraction efficiency (time, temperature, humidity, pH), drainage efficiency of post-extraction residues and directions of their management. The final process optimization is crucial. Despite the development of assumptions for various technologies, excess sewage sludge remains a big problem for sewage treatment plants. The high costs of enzymatic hydrolysis, thermal hydrolysis and ultrasonic methods and the need for a neutralizing agent in acid solubilization limit the rapid implementation of these processes in industrial practice. [Image: see text]

AbstractIn recent times, the issue of plastic recycling has become one of the leading issues of environmental protection and waste management. Polymer materials have been found an application in many areas of daily life and industry. Along with their extended use, the problem of plastic wastes appeared because, after withdrawal from use, they became persistent and noxious wastes. The possibility of reusing polymeric materials gives a possibility of valorization—a second life—and enables effective waste utilization to obtain consumable products. The 3D printing market is a well-growing sector. Printable filaments can be made from a variety of thermoplastic materials, including those from recycling. This paper focuses on a review of the available literature on the production of filaments for 3D printers from recycled polymers as the alternative to present approach of central selective collection of plastics. The possibility of recycling of basic thermoplastic materials and the impact of processing on their physicochemical and mechanical properties were verified (Lanzotti et al. 2019). In addition, commercially available filaments produced from recycled materials and devices which allow self-production of filaments to 3D printing from plastic waste were reviewed.

AbstractThis study aims to explore the development of sustainable fertilizers from waste materials of a biogas plant and a brewery. These wastes, rich in organic carbon and nitrogen, were processed with sulfuric(VI) and phosphoric(V) acid mixture, facilitating the production of free amino acids and achieving waste sanitization. This treatment produced by-products, which extended the range of possible applications. The highest concentration of free amino acids (360 mg/l) was achieved through hydrolyzing with a 40% concentration medium over 24 h. In this case, the maximum levels were recorded for beta-alanine (69.3 mg/l), glycine (46.8 mg/l), isoleucine (43.5 mg/l), proline (36.2 mg/l), and valine (31.5 mg/l). The study presents two fertilizer technologies, with and without micronutrients, that satisfy European Parliament Regulation 2019/1009 (Ntot > 2%, Norg > 0.5%, Corg > 3%). Bioavailability of nutrients in the formulations ranged from 60 to 100%. The efficacies of these fertilizers were evaluated in 30-day pot trials with various plant species, with both single application and fertigation tested. Multielement analysis confirmed high nutrient transfer in the soil-plant system, and the inclusion of micronutrients led to biofortification of plant biomass in Cu (48.3 ± 7.2 mg/kg), Mn (249 ± 37 mg/kg), Zn (164 ± 25 mg/kg), and Fe (211 ± 32 mg/kg). These sustainable fertilizers present an alternative to traditional, non-renewable fertilizers and offer promising solutions for precision agriculture and environmentally conscious production.
Graphical abstract