Methane yield and microscopic observation as monitoring biofilm behaviour parameters, during start up phase of anaerobic inverse fluidized bed reactor

Anaerobic biofilm behavior on polyethylene and Extendosphere™ supports was evaluated during start-up of an inverse fluidized bed reactor using methane yield and microscopic observation as parameter monitoring techniques. Two anaerobic inverse fluidized bed reactors were used, one filled with triturated polyethylene as solid carrier material (diameter = 380 μm, density = 926 kg/m3) and the other with Extendosphere™ (diameter = 147 μm, density = 700 kg/m3). Each support material was used at up to 25% of its working volume (polyethylene = 1.2 l, Extendosphere™ = 1.9 l). Both reactors were started up in sequencing batch mode, applying organic loading rates of 0.5 to 14 g COD/l.d. Both supports exhibited rapid biofilm growth during start-up. Maximum surface colonization was 46% with the polyethylene and 100% with Extendosphere™. Both supports had a methane yield of 0.298 l CH4/g COD at 10 and 14 g COD/l.d, respectively. Digital microscopic observation results coincided with methane yield results, confirming each to be viable for parameter monitoring of biofilm growth. Data generated by these two techniques is different and complementary, and in conjunction they constitute a highly effective monitoring method of biofilm growth.Key words: Anaerobic digestion, biofilm, inverse fluidized bed reactor, methane yield

AMATE PAPER IN PULP OF COFFEE (Coffea arabica) (BENEFIT WET RESIDUE)

Amate (amatl) is a handmade paper of Mexico made by Otomi Indians. This craft is made from bark of tree bark amate or jonote. It is originally developed in the states of Puebla, Hidalgo and Veracruz especially in San Pablito, Puebla. However, amate paper is sold as background Nahua paintings by artists from the state of Guerrero. Amate paper paintings are a combination of Nahua and Otomi traditions. While there have been some minor innovations, the amate paper is still done with the same basic process used in the pre-Hispanic period by obtaining a classical amate tree bark fiber. This is negatively affecting the ecosystem of the North of Puebla and forcing vendors bark in search of other species, so it is necessary to make paper amate more sustainably, including new types of bark from other species and by-products of agro-industries such as rice, coffee sugar cane, and other types of fiber that have high-availability The objective of this work was to analyze and compare the Chemical pulp of coffee characteristics, as raw material for amate paper of higher quality than that produced from the bark of other species. The results showed that the structural and chemical characteristics of coffee pulp cellulose pulp showed ease of paper making, due to its properties of adherence, formation and agglutination of fibers similar to the high quality of the final product as the amate tree bark-derived paper

Papel amate de pulpa de café (Coffea arabica) (residuo de beneficio húmedo)

Amate (amatl) es un papel hecho a mano de México hechas por indígenas otomíes. Esta artesanía es hecha de corteza del árbol amate o jonote. Es originalmente desarrollado en los estados de Puebla, Hidalgo y Veracruz sobre todo en San Pablito, Puebla. Sin embargo, el papel amate se vende como fondo de las pinturas realizadas por artistas nahuas del estado de Guerrero. Las pinturas de papel amate son una combinación de tradiciones nahuas y otomíes. Si bien ha habido algunas innovaciones menores, el papel amate se sigue haciendo con el mismo proceso básico que se utilizó en el período prehispánico mediante la obtención de fibra de la corteza del árbol de amate clásico. Esto está afectando negativamente el ecosistema del norte de Puebla y obligando a los vendedores de corteza a la búsqueda de otras especies, por lo que es necesario hacer papel amate de forma más sostenible, incluyendo nuevos tipos de corteza de otras especies y subproductos de agroindustrias como arroz, café caña de azúcar, y otros tipos de fibra que tengan alta disponibilidad. El objetivo de este trabajo fue analizar y comparar las características químicas de la pulpa de café, como materia prima para papel amate de mayor calidad, que el producido con la corteza de otras especies. Los resultados mostraron que las características estructurales y químicas de la pulpa celulósica de pulpa de café presentaron facilidad de fabricación de papel, debido a sus propiedades de adhesión, formación y aglutinación de fibras similares a la alta calidad del producto final como el papel amate derivado de corteza del árbol.</jats:p

Lignocellulosic biowastes as carrier material and slow release electron donor for sulphidogenesis of wastewater in an inverse fluidized bed bioreactor

Industrial wastewaters containing high concentrations of sulphate, such as those generated by mining, metallurgical and mineral processing industries, require electron donor for biological sulfidogenesis. In this study, five types of lignocellulosic biowastes were characterized as potential low-cost slow release electron donors for application in a continuously operated sulphidogenic inverse fluidized bed bioreactor (IFBB). Among them, natural scourer and cork were selected due to their high composition of volatile solids (VS), viz. 89.1 and 96.3%, respectively. Experiments were performed in batch (47 days) and in an IFBB (49 days) using synthetic sulphate-rich wastewater. In batch, the scourer gave higher sulphate reduction rates (67.7 mg SO42- L-1 day-1) in comparison to cork (12.1 mg SO42- L-1 day-1), achieving >82% sulphate reduction efficiencies. In the IFBB packed with the natural scourer, the average sulphate reduction efficiency was 24 (±17)%, while the volumetric sulphate reduction rate was 167 (±117) mg SO42-L-1 day-1. The long incubation time in the batch experiments (47 days) allowed higher sulphate reduction efficiencies in comparison to the short hydraulic retention time (24 h) in the IFBB. This suggests the hydrolysis-fermentation was the rate-limiting step and the electron donor supply (through hydrolysis of the lignocellulosic biowaste) was limiting the sulphate reduction. Lignocellulose as carrier material and slow release electron donor for sulphidogenesis

Hydrodynamics and mathematical modelling in a low HRT inverse fluidized-bed reactor for biological sulphate reduction

Biological reduction of sulphate at low hydraulic retention time (HRT) is presented in this paper. A sulphidogenic inverse fluidized-bed bioreactor (IFBB) was operated successfully at a progressively decreasing HRT from 1 to 0.125 days for a total of 155 days. Synthetic wastewater containing sulphate at a concentration of 745 (± 17) mg/L was used. COD was supplied as lactate in variable concentrations at COD/SO4 2− ratios of 1.2–2.4. The pH of the feed ranged between 5.2 and 6.2. The highest measured removal rates were 2646 and 4866 mg SO4 2−/L day at an HRT of 0.25 and 0.125 days, respectively, using a COD/SO4 2− ratio of 2.3. The biological sulphate reduction was limited by the influent COD concentrations at a COD/SO4 2− ratio < 2.3. The IFBB ensured biomass retention at a maximum liquid residence time of θ = 3.84 (± 0.013), according to the residence time distribution analysis. Hydrodynamic studies were carried out at recirculation rates of 0, 200, 300, 350, 400, and 500 L/h to measure the relative bed expansion, the mixing pattern, and the fluidization characteristics of the reactor. A dynamic model is also developed based on COD and sulphate as the two limiting substrates in a Monod-type kinetic equation describing the kinetics of lactate oxidation by SRB. A set of the following parameters YVSS/COD′ = 0.23 mg COD of VSS/mg lactate, µmax = 1.758 day− 1, KCOD = 956 mg COD of lactate/L, KSO4 = 316 mg SO4 2−/L, kd = 0.024 day− 1, tres = 5.7 days, and kexchange = 0.4 day− 1 simulated adequately the residual effluent COD and sulphate concentrations, the produced sulphide concentration as well as the pH of the IFBB effluent. Low HRT values, shown efficient in this study, are prerequisite for industrial applicability and economic feasibility of the sulphur reduction process. In addition, the developed model can be used for optimum experimental design and further process upscale and development

Carbohydrate based polymeric materials as slow release electron donors for sulphate removal from wastewater

Many industrial sulphate rich wastewaters are deficient in electron donors to achieve complete sulphate removal. Therefore, pure and expensive chemicals are supplied externally. In this study, carbohydrate based polymers (CBP) as potato (2 and 5 mm3), filter paper (2 and 5 mm2) and crab shell (2 and 4 mm Ø) were tested as slow release electron donors (SRED) for biological sulphate reduction at 30 °C and initial pH of 7.0. Using the CBP as SRED, sulphate reduction was carried out at different rates: filter paper 0.065-0.050 > potato 0.022-0.034 > crab shell 0.006-0.009 mg SO42-.mg VSS-1d-1. These were also affected by the hydrolysis-fermentation rates: potato 0.087-0.070 > filter paper 0.039-0.047 > crab shell 0.011-0.028 mg CODS.mg VSS-1d-1, respectively. Additionally, the sulphate removal efficiencies using filter paper (cellulose, > 98%), potato (starch, > 82%) and crab shell (chitin, > 32%) were achieved only when using CBP as SRED and in the absence of other easily available electron donors. This study showed that the natural characteristics of the CBP limited the hydrolysis-fermentation step and, therefore, the sulphate reduction rates