Search

This paper uses a systems thinking approach to analyze the elements that influence biowaste composting implementation. The review of local, national, and international experiences as well as the knowledge gained by the monitoring of the operation of five biowaste composting facilities in Valle del Cauca (Colombia) over an 8-year period has enabled to identify the elements that interact in an integrated composting system. Twenty-five key elements were identified and divided into four subsystems relevant to composting performance: quality and commercialization of the product, technological component, substrate characteristics, and business and financial management. Several causal diagrams were produced illustrating the interactions and integrating those elements. The systemic analysis helped to elucidate key strategies to improve biowaste composting sustainability: promoting administration within a business perspective, promoting marketing and commercialization initiatives, and implementing local technological development. In addition, some strategies more distant along the causal chain were proposed such as: developing standards and public policies to promote source separation, recognizing the economic and environmental benefits of composting, encouraging the use of products, such as compost, setting product quality standards in accordance with the potential uses of products and supporting technological development. [ABSTRACT FROM AUTHOR]

The development of processes for the production of biopolymer materials is being stimulated by a combination of factors. These factors include the negative effects of petrochemical-derived plastics on the global environment, depletion of global fossil fuel supplies, and the growing demands of an ever-increasing population for the products deemed necessary for an affluent modern lifestyle. In particular, polyhydroxyalkanoates have attracted attention as environmentally friendly alternatives to the synthetic polymers that are commonly used. Polyhydroxyalkanoates are polyesters produced and accumulated in intracellular granules by many microorganisms. Because they are biodegradable and biocompatible and can be produced by fermentation of renewable feedstocks, they are considered attractive substitutes for petroleum-derived polymers. To create bacterial polyesters, crude and waste plant oils, which can be difficult to dispose of, can be recovered and used as feedstock. This paper gives an overview of the potential for the production of polyhydroxyalkanoates with useful physicochemical properties by bacteria grown on renewable resources such as plant oils. [ABSTRACT FROM AUTHOR]

The anaerobic treatment of municipal wastewater (WW) results in low biogas production due to its relatively low concentration of organic matter. To overcome this problem, this paper assesses the potential of combining forward osmosis (FO), as a pre-treatment to concentrate real municipal WW with anaerobic digestion (AD), with the aim of enhancing methane production. A FO unit with a Toray TFC membrane sheet was operated to obtain a water recovery of 50% and 70% from municipal WW. The concentrates obtained from this process were used as substrate for biochemical methane potential (BMP) tests, where their maximum methane production potential was assessed under two different temperatures (25 °C and 35 °C). Results showed a substantial increase in the conversion of chemical oxygen demand (COD) into methane when concentrated WW was used as compared to non-concentrated WW under both temperatures, obtaining the maximum methane production at 35 °C. The occurrence of eighty pharmaceutical compounds (PhACs) during the FO process and the subsequent anaerobic treatment was also monitored. Finally, antibiotic resistance genes (ARGs) related with the main groups of antibiotics present in the WW (bla KPC , ermB , qnrS , sul1 and tetW) were also analyzed before and after the anaerobic treatment. A significant reduction was observed, with less ARGs being detected after the anaerobic treatment indicating that AD is a good strategy to partially remove ARGs from municipal WW. [Display omitted] • Forward osmosis is a suitable process to concentrate municipal wastewater. • Anaerobic treatment of concentrated municipal wastewater gives higher CH 4 yield. • Some pharmaceutical compounds are completely removed during anaerobic treatment. • Anaerobic treatment of municipal wastewater reduces antibiotic resistance genes. [ABSTRACT FROM AUTHOR]