Decomposition dynamics altered by straw removal management in the sugarcane-expansion regions in Brazil

Soil Research ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 41 ◽  
Author(s):  
Letícia L. Varanda ◽  
Maurício R. Cherubin ◽  
Carlos E. P. Cerri

Brazilian bioenergy production based on sugarcane is globally known as a sustainable energy matrix. In order to supply the growing demand for biofuels, the sugarcane area expanded by 46% in the last decade in Brazil. In addition, the industry’s interest in using sugarcane straw as raw material for bioenergy production has recently increased. Thus, understanding the straw decomposition dynamics in these new frontiers is imperative to support decision-making that will define a sustainable straw removal rate. A field experiment was conducted in three sites under a climate and soil gradient (from central to south) within the sugarcane-expansion region (i.e. Goiás, Mato Grosso do Sul and Paraná states) to evaluate the straw decomposition. The amounts of 3, 6 and 12 Mg ha–1 of straw (dry mass, DM) were left on the soil surface after harvesting, representing the straw removal rates of about 75, 50 and 0% respectively. We quantified DM loss, carbon (C) and nitrogen (N) contents and biochemical composition of the straw throughout a crop cycle (300 days). In addition, visual changes in the decomposing straw were evaluated through scanning electron microscopy. An exponential model was efficiently fitted to data of DM loss, describing the pattern of straw decomposition over time. The DM, C losses and cellulose and hemicellulose contents of straw changed over time among sites, reflecting the local edaphoclimatic conditions favourable for decomposition. The C:N ratio decreased from 106:1 to 65:1 for the lowest straw amount and 41:1 for the highest straw amount, and were correlated with the lowest (65%) and highest (76%) DM loss respectively. After the crop cycle, sugarcane straw changed visually, possible due to loss of biochemical compounds. In conclusion, lower straw removal induced an increase in the straw decomposition rate (higher DM loss over time), which could boost positive agronomic impacts such as increased C stock and improved soil quality.

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 758 ◽  
Author(s):  
José G. de A. Sousa ◽  
Maurício R. Cherubin ◽  
Carlos E. P. Cerri ◽  
Carlos C. Cerri ◽  
Brigitte J. Feigl

The understanding of sugar cane straw decomposition dynamics is essential for defining a sustainable rate of straw removal for bioenergy production without jeopardising soil functioning and other ecosystem services. Thus, we conducted a field study in south-east Brazil over 360 days to evaluate sugar cane straw decomposition and changes in its composition as affected by increasing initial straw amounts and management practices. The sugar cane straw amounts tested were: (1) 3.5 Mg ha–1 (i.e. 75% removal); (2) 7.0 Mg ha–1 (i.e. 50% removal); (3) 14.0 Mg ha–1 (i.e. no removal); and (4) 21.0 Mg ha–1 (i.e. no removal plus 50% of the extra straw left on the field). In addition, two management practices were studied for the reference straw amount (14 Mg ha–1), namely straw incorporation into the soil and irrigation with vinasse. The findings showed that dry mass (DM) loss increased logarithmically as a function of the initial amount left on the soil surface. An exponential curve efficiently described straw DM and C losses, in which more readily decomposable compounds are preferably consumed, leaving compounds that are more recalcitrant in the late stages of decomposition. After 1 year of decomposition, net straw C and N losses reached approximately 70% and 23% respectively for the highest initial straw amounts. Straw incorporation in the soil significantly accelerated the decomposition process (i.e. 86% DM loss after 1 year) compared with maintenance of straw on the soil surface (65% DM loss after 1 year), whereas irrigation with vinasse had little effect on decomposition (60% DM loss after 1 year). We conclude that straw decomposition data are an essential starting point for a better understanding of the environmental effects caused by straw removal and other management practices in sugar cane fields. This information can be used in models and integrated assessments towards a more sustainable sugar cane straw management for bioenergy production.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2741
Author(s):  
Pengcheng Lv ◽  
Ruihong Meng ◽  
Zhongyang Mao ◽  
Min Deng

In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.


Mining Revue ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 40-44
Author(s):  
Eugen Traistă ◽  
Camelia Bădulescu ◽  
Maria Lazăr ◽  
Camelia Traistă

Abstract Metallurgical slag is one of the most common industrial wastes. Many of these wastes are not stable over time, by reacting with water and air, continuously generating emissions of heavy metals. Metallurgical slag processing is necessary for at least two reasons: reducing pollutant emissions and broadening the raw material base. The recovery of these slags is very difficult because they are the result of metallurgical processes that aimed to fix metals considered impurities in chemical matrices as stable as possible. This paper presents the initial research on the behavior of metallurgical slags against different leaching technologies.


Author(s):  
Mayra Mariño ◽  
Daniela Cypriano ◽  
Ljubica Tasic

Our study was motivated by the large amount of crop residues produced in Brazil, which represent underutilized waste biomass and a serious threat to the environment because of the landfilling. For example, even though the corn crop is not popular in Brazil, it is produced in the area of around 18-20 million hectares with an average production of 5-6 t ha-1. That is the reason to seek for the crop residues value-added applications as proposed in the present study. Four Brazilian crop waste biomass: orange bagasse, corn husks, sugarcane straw and coffee residues were used for cellulose nanofibers (CNF) production. CNFs were prepared using alkali treatment, followed by bleaching with sodium chlorite and extraction with oxalic acid. All steps were applied under moderate conditions of temperature and pressure, such as temperature of 120 °C and below, water solutions with chemicals’ concentrations lower that 10% and short sonication pulses. CNFs with diameters in the range 50-70 nm were obtained and products from orange bagasse and corn husks presented high crystallinity indexes (CI), 0.72 and 0.75, respectively. The highest CNF yield was obtained from corn husks (38.5%) followed by sugarcane straw (24.0% with CI of 0.69). CNFs obtained from coffee residues showed a CI value of 0.65 after two bleaching steps. Different CNF morphologies were obtained according to the raw material. The four-crop waste biomass can be considered as excellent starting materials for CNF production in the four-steps process that adds new value to agro-industrial waste and might bring great economical valorization to Brazilian crops production.


2019 ◽  
Vol 12 (4) ◽  
pp. 944-957 ◽  
Author(s):  
Lauren Maine Santos Menandro ◽  
Luana Oliveira de Moraes ◽  
Clovis Daniel Borges ◽  
Maurício Roberto Cherubin ◽  
Guilherme Adalberto Castioni ◽  
...  

2011 ◽  
Vol 284-286 ◽  
pp. 193-196
Author(s):  
Zhao Sheng Chen

Three natural graphite flakes (35, 50 and 80 mesh) were used as raw material. Exfoliated graphite (EG) was prepared by rapidly heating expandable graphite to 1000 °C in a muffle and by irradiating it in a microwave oven with a power of 280 W for 40 s, respectively. The EG samples were used for removing methyl orange (MO) from aqueous solution. The effect of preparation technique of EG (particle size of natural graphite and exfoliation method of expandable graphite) on MO removal properties was investigated, and a higher removal rate was achieved.


2008 ◽  
Vol 54 (No. 2) ◽  
pp. 72-77 ◽  
Author(s):  
A. Kumari ◽  
K.K. Kapoor ◽  
B.S. Kundu ◽  
R. Kumari Mehta

The production of organic acids and changes during decomposition of rice straw amended with tricalcium phosphate (TCP) and Udaipur rock phosphate (URP) were studied under laboratory conditions. The organic C content of rice straw decreased and total N increased with time, resulting in a decrease in C:N ratio as the decomposition progressed. The pH decreased to acidic range in all the treatments on day 15, but became alkaline again later on. Soluble P increased at 15 days after incubation, declined later during decomposition, and was highest in the treatments containing TCP and <I>Aspergillus awamor</I>i inoculation. Citric, oxalic, formic and maleic acids were detected during decomposition of rice straw and maximum amounts were present on day 15. Citric and oxalic acids were responsible mainly for P solubilization from TCP and URP; generally, citric acid was the most effective in P solubilization.


GCB Bioenergy ◽  
2018 ◽  
Vol 11 (2) ◽  
pp. 427-443 ◽  
Author(s):  
Sierk de Jong ◽  
Mark Staples ◽  
Carla Grobler ◽  
Vassilis Daioglou ◽  
Robert Malina ◽  
...  

2020 ◽  
Vol 12 (21) ◽  
pp. 8847
Author(s):  
Ahmed Sharaf ◽  
Bing Guo ◽  
David C. Shoults ◽  
Nicholas J. Ashbolt ◽  
Yang Liu

Compared with conventionally collected sewage, source-diverted greywater has a higher potential for on-site treatment and reuse due to its lower contaminant levels and large volume. A new design of granular activated carbon (GAC) biofilters was developed by incorporating unsaturated and saturated zones in a single stage to introduce an efficient, passive, and easy-to-operate technology for greywater on-site treatment at the household scale. The design was customized for its intended application considering various aspects including the reactor’s configuration, packing media, and feeding strategy. With the highest hydraulic and organic loadings of 1.2 m3 m−2 d−1 and 3.5 kg COD m−2 d−1, respectively, and the shortest retention time of 2.4 h, the system maintained an average total chemical oxygen demand removal rate of 94% with almost complete removal of nutrients throughout its 253 days of operation. The system showed a range of reduction efficacy towards five surrogates representing viruses, bacteria, and Cryptosporidium and Giardia (oo)cysts. A well-functioning biofilm was successfully developed, and its mass and activity increased over time with the highest values observed at the top layers. The key microbes within the biofilter were revealed. Feasibility of the proposed technology was investigated, and implications for design and operation were discussed.


2011 ◽  
Vol 695 ◽  
pp. 553-556
Author(s):  
Yu Hong Tian ◽  
Xin Zhe Lan ◽  
Qiu Li Zhang ◽  
Juan Qin Xue ◽  
Yong Hui Song ◽  
...  

The low-cost blue coke industrial by-product, blue coke powder was used as raw material for the production of porous carbons adsorbent by steam activating at temperature of 800°C under the atmosphere of N2 for 60 minutes. The specific surface area and pore properties of the adsorbent were characterized by using N2 adsorption-desorption isotherms. Furthermore, the adsorption effects of the adsorbent for ammonia nitrogen in coking wastewater were investigated in terms of particle size, dosage of absorbent and adsorption time. The results show that the specific surface area is 620.94m2/g, the total pore volume is 0.4442cm3/g and the average mesopore size is 4.5808nm, the adsorbent possesses predominant mesoporous structures. In aeration, the removal rate of ammonia nitrogen can reach to 39.5% under the conditions of the ammonia nitrogen concentration of 625mg/L, the dosage of adsorbent 10g/L at the adsorption time of 60 minutes.


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