Circular Bioeconomy in the Amazon Rainforest: Evaluation of Açaí Seed Ash as a Regional Solution for Partial Cement Replacement

Abstract

Açaí seed ash (ASA) is a waste product from processing the açaí fruit and burning the seeds for cogeneration purposes. The present study evaluated the use of ASA from the Brazilian Amazon as partial Portland cement replacement in self-leveling mortars (SLM) for social-interest buildings. The fresh and hardened state properties of mortars were accessed with 5% and 10% ASA content, and a life cycle assessment was performed to evaluate the greenhouse gas (GHG) emissions. The maximum transport distance to enable ASA as a building material was determined by a sensitivity analysis, and specific carbon-efficiency indicators for SLM were proposed and validated. The results showed that using up to 10% ASA as cement replacement was technically and environmentally feasible since the mechanical performance was maintained and GHG emissions decreased up to 8%. The sensitivity analysis revealed that transport efficiency is crucial for ASA applications far from its production area; therefore, it should be evaluated as a regional building material. The work brings an important contribution to regional sustainable development by assessing the characteristics of a residual material and proposing the reuse of waste, reducing GHG emissions from the cement industry, and stimulating the circular bioeconomy in the Brazilian Amazon region.

Methods for Evaluating Pozzolanic Reactivity in Calcined Clays: A Review

“…The ashes of vegetable origin, for example, are pozzolans studied with the purpose of developing more sustainable cementitious elements and with enhanced properties. The use of rice husk ash [ 48 , 49 , 50 ] and sugar cane bagasse ash [ 51 ] promotes the characteristics of better durability and increased mechanical strength when used in mortars and concretes behind lower shrinkage rates and decreases in the emission of pollutant gases such as CO 2 . Other materials are used with this same purpose.…”

Life Cycle Thinking for a Circular Bioeconomy: Current Development, Challenges, and Future Perspectives

“…In America, studies have also focused on biorefinery systems to produce biogas [52][53][54] and biodiesel [53,55]. Moreover, other studies assessed other products rather than biofuels, such as bio-based proteins [56], biopolymers [57], and bio-based construction materials [58].…”

“…In this review, only six (out of 16) studies that processed vegetal wastes used biorefinery processes to produce biodiesel [42,45,46,53], bioethanol [23,63], or biogas [52,53]. The other ten documents assessed the production of other bio-based products, such as biopolymers [34,57], bio-based pigments [37], lacquer [38], antioxidants [49], fiber and protein [62], xylitol [51], mortar (for construction) [58], and animal feed [25,64].…”

“…Considering the CBE sectors, agroindustry has a notorious predominance, and 50% of the studies (19 out of 38) applied life cycle tools to assess the sustainability of agricultural and agroindustry wastes. Agroindustry includes the cultivation of crops for manufacturing purposes, e.g., the production of fruit pulp and juices [37,42,58,64], olive oil [46], sugar [51] and rice [25,57], as well as for biorefinery purposes, e.g., sugarcane [23,51,52], Ricinus [53], or safflower [63] to produce biofuels (i.e., biodiesel or bioethanol). Other studies applied LCT to a combination of agroindustry with the textile [35] or plastic industries [36].…”

“…These countries might be the group that benefits the most from (bio)economic growth [70]. Basic needs fulfillment includes food and energy security that a CBE can directly satisfy [58]. In this regard, it is imperative to develop and offer win-win CBE solutions for Africa in order to optimize economic growth [60], the reduction of environmental impacts, and improve the population's quality of life.…”