Cláudio Mudado Silva

Caracterização tecnológica, para produção de celulose, da nova geração de clones de Eucalyptus do Brasil

Last generation of Eucalyptus clones pulped by the main Brazilian kraft pulp mills were used for this study. Detailed chemical analysis of the woods were carried out to establish the wood quality. Laboratory simulation of a modern continuous digester technique was used for pulp production. Results demonstrated the high quality of Eucalyptus clones wood that are being planted in Brazil for kraft pulp production.

Recovery of drippers clogged by use of water high in iron content

A study was carried out (Reciclean) to evaluate the efficiency of using the phosphoric acid, sodium hypochlorite, a commercial product and mechanical impact for cleaning the drippers in which the clogging was due to the presence of high iron content in water. The experiment was set up in the Vista Alegre Farm, located in Jaboticatubas County - Minas Gerais State. A drip irrigation system was adopted for the accomplishment of the tests. Eight treatments were tested, of which, seven with application of chemical products and one with mechanical impact. In accomplishing the chemical treatments, the phosphoric acid was used at pH 2 and 3, sodium hypochlorite at 100, 50 and 25 mg L-1 chlorine and Reciclean at 50 and 25 mg L-1. According to the results, the following conclusions were drawn: the treatment using the phosphoric acid at pH 2 provided the best results, when evaluating the improvement of uniformity in the irrigation system, since it showed the highest increase in the values of uniformity coefficients (CUD and CUC); however, it is an expensive treatment. The treatment with 25 mg L-1 chlorine presented the best benefit/cost relation, since it showed to be the cheapest besides being the second best in improving the uniformity of the irrigation system. The mechanical impact is a good alternative to recover the drip irrigation systems, principally under organic farming.

Eradication of Plant Pathogens in Forest Nursery Irrigation Water

Interest in rational use and reuse of water has increased in recent years, especially in forest nurseries. However, before water can be reused in nurseries, it must be properly treated to eradicate plant pathogens to reduce risks of pathogen dispersal and losses to disease. In the present study, the efficacy of irrigation water treatment by ultrafiltration and conventional physical-chemical treatment was studied to eliminate Botrytis cinerea, Cylindrocladium candelabrum, Ralstonia solanacearum, and Xanthomonas axonopodis, the pathogens most commonly found in Brazilian forest nurseries. Ultrafiltration eradicated over 99% of R. solanacearum, X. axonopodis, and B. cinerea and 100% of C. candelabrum. The few remaining cells or conidia of R. solanacearum and B. cinerea did not induce disease in irrigated rooted cuttings. Flocculation and fast sand filtration used in physical-chemical treatment completely eliminated C. candelabrum but the other pathogens were only removed after chlorination of the filtered water. Both forms of treatment are viable, practical, and safe methods for plant pathogen removal from irrigation water.

AVALIAÇÃO DO POTENCIAL DE APROVEITAMENTO ENERGÉTICO DOS RESÍDUOS DE MADEIRA E DERIVADOS GERADOS EM FÁBRICAS DO POLO MOVELEIRO DE UBÁ - MG

O presente estudo avaliou o potencial de reaproveitamento energetico dos residuos de madeira e seus derivados gerados no Polo Moveleiro de Uba, MG. Paineis reconstituidos de MDF (medium density fiberboard), aglomerado e compensado foram caracterizados e classificados, identificando assim as oportunidades e possiveis limitacoes quanto a sua utilizacao. Por meio de diagnostico realizado em 11 fabricas de moveis, verificou-se que os residuos de madeira compreendem mais de 90 % do total dos residuos solidos gerados. Alem da grande quantidade gerada, nao foi identificada nenhuma acao integrada entre as fabricas do Polo para o adequado gerenciamento dos residuos, negligenciando seus riscos ambientais e sanitarios, bem como seu potencial energetico. Contudo, os teores de umidade e poder calorifico dos residuos demonstraram potencial para o seu reaproveitamento energetico atraves da producao de briquetes. Os gases gerados em ensaios de combustao dos residuos nao apresentaram substâncias ou compostos toxicos acima dos limites preconizados pelas normas ambientais, verificando, neste aspecto, um bom desempenho ambiental para o aproveitamento destes residuos conforme proposto pelo presente estudo. Entretanto, as cinzas dos residuos de aglomerado BP (baixa pressao) e FF (finish foil) apresentaram elevadas concentracoes de cromo, enquadrando-se como Classe I (perigosos), segundo a ABNT/NBR 10004/2004.

Membrane treatment of the bleaching plant (EPO) filtrate of a kraft pulp mill.

The objective of this study was to evaluate the use of membrane technology to treat oxygen and peroxide-reinforced extraction stage (EPO) filtrate from a kraft pulp mill bleach plant. Three different types of tubular membranes were tested in a pilot plant: (i) tight ultrafiltration (UF); (ii) open UF followed by nanofiltration (UF+NF); and (iii) nanofiltration (NF). According to the separation performance, considering the chemical oxygen demand (COD) and colour removal, permeate flux, operational simplicity and cost, the results indicated that the best option for treatment of (EPO) filtrates was the tight UF membrane. This membrane obtained a COD removal of 79% with a colour reduction of 86%. The effect of (EPO) filtrate UF treatment on the mill effluent treatment plant was evaluated. Compared with the actual mill effluent, the results indicated that if the UF permeate was recycled in the bleaching area, the COD reduction efficiency increased by 7%, the final effluent colour decreased by 8%, the biological sludge production decreased by 18%, and the energy consumption decreased by 40%. In the tertiary treatment plant, the coagulant dosage decreased by 40%, and the tertiary sludge production decreased by 46%.

Enzymatic bleaching of eucalyptus kraft pulp: effects on the prebleaching filtrate, pulp quality and paper properties

Abstract Enzymatic bleaching appears to be a promising approach for clean bleaching processes and the reduction of bleaching chemical consumption. In this work, the quality of the filtrates and the pulps has been characterized after enzymatic prebleaching stages of eucalyptus kraft pulp. Four different conditions with xylanase were investigated. Following each prebleaching stage, the properties of the pulp [kappa number, brightness, content of hexenuronic acid (HexA), xylan removal, and pulp yield lost], and of the resulting effluents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), color, and conductivity) were determined. In addition, a complete bleaching sequence was performed to characterize the pulp quality at the end of the sequence. Finally, the pulp was refined in a PFI mill, and the mechanical and physical properties of the resulting paper were determined. The best pulp quality was achieved at pH 7, at which a lower kappa number, higher pulp brightness, and smaller amount of HexA were observed. Under this condition, however, a larger yield loss and a higher effluent COD load had to be accepted. After the complete bleaching sequence, the enzymatic treatments yielded pulps with higher brightness and viscosity as well as with a lower kappa number. The enzymatic treatments resulted in small changes in the mechanical and physical properties of the paper handsheets produced.

Avaliação da utilização de composto orgânico produzido a partir dos resíduos de fábrica de celulose quanto aos níveis de organoclorados e metais

Bleached kraft pulp mill sludge may present traces of heavy metals and organochorine compounds even when ECF (elemental chorine free) bleaching sequences are used due to the presence of chlorine dioxide. The objective of this work was to evaluate the absorption potential of heavy metals and organochlorine compounds (PCDD and PCDF) by Brassica juncea when bio-sludge of an activated sludge plant and organic compost prepared from bio-sludge mixed with Eucalyptus bark of a bleached kraft pulp mill. The plants were cultivated in 0.63 dm3 pots in greenhouses during 73 days. The following parameters were monitored in the substrate and in the plants: Fe, Mn, Pb, Ni, Cu, Zn, Cr, Cl-, total organic carbon and AOX (adsorbable organic halogen compounds). Content of heavy metals in the soil after compost application was within the Brazilian legal standards for compost application. Traces of PCDD e PCDF were found in the substrate at concentrations lower than 0.5 ng I-TEQ/kg (ppt). These values were lower than the highest quality criteria of 17 ng I-TEQ/kg from Canada and Germany.

Irrigation of eucalyptus plantation using treated bleached kraft pulp mill effluent

The use of treated pulp mill effluent on eucalyptus plantation appears to be an attractive option for plant nutrition and water supply. It also constitutes a supplementary treatment process and a final disposal option for the mill effluent. This study aimed at the investigation and evaluation of the effects of bleached kraft pulp mill treated effluent on three typical Brazilian soils used for eucalyptus plantation. The effluent was characterized and five different application rates, defined according to the load of sodium, were tested in controlled environment experiments (greenhouse). After effluent application over a six month period an increase in the salinity of the studied soils was observed, although no soil dispersion was detected. The low content of some nutrients in the treated effluent indicated the need for fertilizer complementation. In general, the best biomass productivity and plant growth results were obtained in fine textured soil at a loading rate of 6.49 t Na ha(-1). The good response of the soil-plant system under different effluent application rates showed the feasibility for the eucalyptus irrigation if adequate management practices and monitoring are carried out.

Use of talc for filamentous bulking control in effluent treatment plant

One of the main existing operational problems in activated sludge effluent treatment processes is the poor sedimentation of the biological sludge in the secondary clarifiers. This poor settleability of the sludge is, generally, associated with excessive growth of filamentous bacteria in the bioreactor causing sludge filamentous bulking. In Brazil, many pulp and paper mills have faced problems related to sludge filamentous bulking in their effluent treatment plants experiencing a significant reduction in COD and BOD removal efficiency and a loss of suspended solids in the treated effluent. The addition of talc to increase floc density for the control of filamentous bulking has been studied. The objective of this study was to test the use of talc for the control of filamentous bulking. The bio-sludge used was obtained from a recycling paper mill and had an abundance of filamentous bacteria Type 021N. The experiment consisted of five bioreactors operating batch wise with sludge age of ten days. Different talc applications were used: 0%, 25%, 50%, 75% and 100% in relation to the total suspended solids in the aeration tank. The following analyses were carried out to monitor the system: suspended solids, sludge volumetric index (SVI) and chemical oxygen demand. Successive additions of talc contributed for the reduction of IVL. Dosages of 75% and 100% showed to be most efficient to improve settleability of the sludge. The presence of talc did not interfere with biological activity of the sludge. However, it was observed an increase of the total suspended solid concentration in the aeration tank. The addition of talc had a temporary effect on sludge settleability, so it was necessary to add repeatedly talc in the reactor in order to maintain a low sludge volumetric index.

Washing, bleaching and characterisation of eucalyptus pulp from ethanol pulping

The present study analyzed eucalyptus pulp produced by the ethanol-based organosolv process submitted to different bleaching strategies. Washing tests with ethanol and alkaline solution, cold caustic extraction (CCE), oxygen delignification and bleaching through Dhot(EP)DP bleaching sequence were performed. Different washing strategies were investigated. In washings with NaOH solution, different charges, times and temperatures were tested. The best result was obtained with NaOH charge of 40 kg/t, 3 min and 90°C, reducing the kappa number by 33 %. CCE of the brown stock resulted in a reduction of the kappa number by 29%. The highest kappa number reduction was reached by bleaching with the O/ODhot(EP)DP sequence. Delignification degree in the oxygen stage was 79.2%, indicating no need for prior treatments as ethanol or alkaline solution. The final bleached pulp had a brightness of 91.7% ISO, viscosity of 546 cm/g and low content of hemicelluloses.