A compostagem como alternativa para redução e aproveitamento de resíduos sólidos orgânicos de grandes geradores de resíduos no município de Goiânia: estudo de caso do restaurante Cidadão do setor Campinas – Goiânia/GO

Este trabalho apresenta um estudo de caso do restaurante Cidadão, localizado na Avenida Anhanguera, n. 8.473, Quadra 97, Setor Campinas – Goiânia/GO. Pretende-se analisar, caracterizar e quantificar os resíduos através de dois métodos e, a partir dos resultados de composição obtidos, avaliar se a compostagem é viável ou não. São servidas diariamente cerca de 2.400 refeições, e os locais de geração levantados foram a cozinha e o salão de alimentação. A partir dos resultados e da literatura estudada, entende-se que a compostagem é viável no local, e o melhor método a ser aplicado é o de leiras estáticas com aeração natural. O emprego da compostagem em resíduos sólidos urbanos (RSU) aumenta consideravelmente a vida útil dos aterros sanitários, correspondendo a um acréscimo de aproximadamente 0,342 anos aos locais de disposição final relativos apenas aos grandes geradore

Sugarcane bagasse ash and its blends with triple-superphosphate reduce the dependency on rock phosphate

Optimal crop production depends on a supply of phosphorus. Sugarcane bagasse ash (BA), a by-product of sugarcane processing, contains up to 1.6 wt% phosphorus. BA use in agriculture can reduce the dependency on rock phosphate.The potential of BA as phosphorus fertilizer was tested for soybeans on Oxisol soil under Brazilian field conditions. Fertilizing effects of 40, 80 and 160 kg/ha P2O5 from BA were compared to conventional fertilization with 40 kg P2O5 from triple-superphosphate (TSP). Additionally, BA/TSP blends consisting of 70% P2O5 from BA and 30 % from TSP (resulting in 32, 65 and 130 P2O5 kg/ha) were evaluated with respect to fertilizing efficiency. The bioavailability of P2O5 from BA to soybeans was lower than from TSP, so that doubling of P2O5 dose was necessary to compensate for the lower offtake. Grain yields following BA-based fertilizations did not statistically differ compared to TSP fertilization, albeit tended to increase by 11% when fertilized with BA/TSP blend supplied at 65 kg P2O5/ha. Thus, while 80 kg P2O5/ha in form of BA could replace 40 kg P2O5/ha in form of TSP, fertilization with 65 kg P2O5/ha in form of BA/TSP could save 50% of TSP and increase the grain yield

Sugarcane bagasse-based ashes as fertiliser for soybeans and the relevance of ash mineral composition on plant phosphorus availability

Sugarcane bagasse, the lignocellulosic remains of sugar cane processing is commonly burnt to generate electricity. Recycling strategies for the resulting ashes rarely take the remaining plant nutrients into account. The objective of this study was to investigate the potential of ashes sourced from combustion and gasification of bagasse alone and in combination with chicken manure and sewage sludge, respectively, as fertiliser for soybeans. The analyses were based on chemical ash characterisation, 31P NMR, X-ray diffraction, sequential phosphorus (P) extraction, P extraction in citric acid and greenhouse pot experiments with soybean plants. Fertilization effects were lower than those of triple-superphosphate and K2SO4 and depended on plant P availability. Calcium-based phosphates dominated in all ashes and determined plant P availability. XRD analyses revealed whitlockite (Ca9M(PO4)7) and CaK2P2O7 in all ashes, while AlPO4 was detected only in an ash with low plant P availability and two undefined P phases and Ca(Na,K)PO4 in ashes with high plant P availability. In conclusion, plant P availability was highest in alkali-rich ashes, as observed in ashes from co-processing bagasse with chicken manure. To increase plant P availability in ashes, we recommend co-combustion of the biomass with sodium and potassium rich biofuels

Soybean Fertilized by P-Phases from Bagasse-Based Materials: P-Extraction Procedures, Diffusive Gradients in Thin Films (DGT), and X-ray Diffraction Analysis (XRD)

The Brazilian sugarcane industry produced around 173 million tons (Mt) of bagasse in 2018. Bagasse is a by-product of juice extraction for ethanol and sugar production and is combusted in order to generate power, producing up to 10 Mt of ash per year. This ash contains various concentrations of plant nutrients, which allow the ash to be used as a crop fertilizer. However, the concentration and extractability of phosphorus (P), an essential plant nutrient, are low in bagasse ash. To increase the P content, we co-gasified and co-combusted bagasse with P-rich chicken manure. The resulting ash was thermochemically post-treated with alkali additives (Na2SO4 and K2SO4) to increase the availability of P to plants. We aimed to: (i) investigate the effect of thermochemical post-treatment of co-gasification residue and co-combustion ash on P availability to soybeans, (ii) explore the potential of chemical extraction methods (citric acid, neutral ammonium citrate, formic acid, and Mehlich-I) and diffusive gradients in thin films (DGT) to predict the availability of P to soybeans, and (iii) identify the responsible P-phases using X-ray diffraction . We evaluated P availability to soybeans growing in Brazilian Oxisol soil in two independent greenhouse pot experiments. The positive effect of thermochemical treatment on P availability from gasification residue was confirmed through the observation of increased P uptake and biomass in soybean plants. These findings were confirmed by chemical extraction methods and DGT. The gasification residue contained whitlockite as its main P-bearing phase. Thermochemical post-treatment converted whitlockite into highly soluble CaNaPO4. In contrast, co-combustion ash already contained highly soluble Ca(Na,K)PO4 as its main P-bearing phase, making thermochemical post-treatment unnecessary for increasing P availability. In conclusion, increased extractability and availability of P for soybeans were closely connected to the formation of calcium alkali phosphate. Our findings indicate that this combined methodology allows for the prediction of P-fertilization effects of ash