No abstract

This study aims to evaluate the Brazilian production of açaí, focusing on its waste generation and addressing mass and energy balances arising from its cultivation, extraction, processing, and waste disposal. A new technological route for açaíʼs waste management was introduced for bioenergy recovery based on the circular economy concept. In 2018, Brazil produced 1.7 million tons of açaí fruit for an income of 1.07 billion USD, and the associated waste generation (seeds) was estimated at 85%. Due to the high production of waste, an innovative approach was developed for a system boundary (conceptual line that divides the system), including the management of solid and liquid wastes through anaerobic digestion (AD). The results showed that, from 1 ton of açaí fruit fed into the facility for processing, 1.2 ton of solid waste and wastewater was generated. This waste was submitted to AD and produced 2.77 m3 of biogas, with a methane composition of 50%. The complete industrial process demands 25 kWh per ton of frozen pulp. The local energy produced by the biogas burning could be recycled and used by the process, establishing a circular energy economy for this sector. With the adoption of AD waste management, about 61% of the external electricity requirement for the açaí fruit processing can be replaced from the biogas produced. The adoption of this technology can be contribute to decarbonization. Furthermore, the implementation of AD could support the transition to a circular economy, with environmental, social, and economic benefits for local and regional sustainable development. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

This study evaluates the benefits of mineral fertilizers replacement for biodigested vinasse. Data from experimental anaerobic digestion (AD) of vinasse were applied to support the analysis. Based on previous experiments, this assessment assumed that vinasse production could reach 2.38 × 10 7 m 3 /year generating around 66,585 MWh/year of electric energy from biogas burning in the Administrative Region of Campinas (ARC). This amount of energy could supply more than 103,000 inhabitants and avoid 35,892 tCO 2eq /year (from electric energy replacement). The biodigested vinasse might also reduce the total N, P, and K mineral fertilizers demand per hectare of sugarcane crop in 30%, 1%, and 46%, respectively, avoiding additional greenhouse gas emissions of 111,877 tCO 2 eq/year. There is no biodigested vinasse surplus for a moderate fertigation rate of 100 m 3 /ha, complying with local environmental laws related to nutrients excess side effects in areas destined to sugarcane crop. Notwithstanding, a Geographic Information System analysis for a small adjacent area to ARC indicated nine different fertigation rates, ranging from 50 to 100 m 3 /ha. Even though the general analysis for ARC shows high NPK replacement levels, the fertigation practices should be subsidized for robust soil analysis and adequate to safe environmental levels. A management tool can be designed using the results here presented to subsidize investments for AD widespread adoption by the sugarcane industry to catch a reasonable practice from the economic and environmental perspectives.

Brazil is currently focused on its energy matrix transition in favor of increasing of the share of renewable energy carriers for both enhanced energy security and mitigation of greenhouse gas emissions. In this context, the country`s pulp and paper industry whose different wastes teams are not generally exploited, could play a critical role. Accordingly, the main objective of this work is to develop a conceptual 'systemic' biorefinery framework integrating the treatment of pulp and paper mill wastewater using upflow anaerobic sludge blanket (UASB) reactor with energy recovery through biogas production and its conversion into heat and power in stationary engines and boilers, respectively. Based on the results obtained through the present case study, it was revealed that the adoption of UASB reactors by the paper mill industry could properly addresses the environmental concerns faced while could contribute to the national agenda favoring an increasing share of renewable energies in the country`s energy matrix. The financial analysis showed that the investment required for the implementation of UASB reactors within a biorefinery platform would be minor vs. the investment in the whole mill and would be returned in 6.4 yr with a high return on investment even when operated at half of operational capacity. Moreover, through the developed UASB reactor-based biorefinery, the Brazilian pulp and paper industry as a whole could avoid 1.06 ×10 5 CO2eq tons, effectively contributing to the decarbonization of the country`s economy.

No abstract

No abstract