Caracterización cinética de la degradación anaerobia termofílica seca de la FORSU. Efecto de diferentes pre-tratamientos sobre la biodegradabilidad del residuo

En el trabajo de investigación se han optimizado las etapas de arranque y estabilización de un reactor semicontinuo para el tratamiento de la fracción orgánica de los residuos sólidos urbanos (FORSU) mediante el proceso de digestión anaerobia termofílica (55 °C) y seca (30% en sólidos totales). La puesta en marcha y estabilización del sistema se ha conseguido en 90 días de operación mediante el empleo de un inóculo adaptado al residuo y a las condiciones de operación a través de la tecnología SEBAC. Por otro lado se ha caracterizado la cinética del proceso y se ha determinado el Tiempo de Retención de Sólidos mínimo y óptimo para la operación semicontinua cuando el sistema es alimentado con FORSU sintética triturada (1 mm) y FORSU industrial con el objeto de estudiar la influencia de la granulometría del residuo. Igualmente, se han aplicado pretratamientos de tipo termoquímicos y biológicos a la FORSU industrial con la finalidad de fomentar la hidrólisis del residuo e incrementar la velocidad global del proceso. Por último, con el objeto de evaluar la influencia de los distintos pretratamientos sobre los principales parámetros de biodegradación y sobre los parámetros cinéticos, se realizaron ensayos de biodegradabilidad en discontinuo y semicontinuo

Manual de laboratorio de la asignatura Tecnología Ambiental

El documento contiene información relativa a la metodología a seguir para desarrollar las prácticas de laboratorio de la asignatura Tecnología Ambiental del Grado en Ingeniería en Tecnologías Industriales. Específicamente, el documento está centrado en las prácticas de Adsorción, Coagulación-Floculación y Sedimentación, contenidos que han sido abordados previamente durante las clases teóricas de la asignatura.Número de páginas: 1

Effect of passively aerated biological pretreatment on different biomasses with diverse lignocellulosic fiber profiles

Passively aerated biological pretreatment was applied to four different lignocellulosic biomasses with varying fiber content profiles: sugar beet pulp (SBP), brewery bagasse (BB), rice husk (RH), and orange peel (OP). In order to analyze the organic matter solubilization yield at 24 and 48 h, different percentages of activated sewage sludge (2.5–10%) were utilized as inoculum. The OP achieved the best organic matter solubilization yield in terms of soluble chemical oxygen demand (sCOD) and dissolved organic carbon (DOC) at 2.5% inoculation and 24 h: 58.6% and 20%, respectively, since some total reducing sugars (TRS) consumption was identified after 24 h. On the contrary, the worst organic matter solubilization yield was obtained with RH, the substrate with the highest lignin content among the tested, with percentages of 3.6% and 0.7% in terms of sCOD and DOC respectively. In fact, it could be considered that this pretreatment was not successful with RH. The optimum inoculation proportion was 7.5% (v/v) except for the OP (2.5% (v/v)). Finally, due to the counterproductive organic matter consumption at longer pretreatment durations, the optimal time for BB, SBP, and OP was 24 h

Editorial of the special issue “Anaerobic co-digestion of lignocellulosic wastes”

Editorial from the special issue Anaerobic Co-Digestion of Lignocellulosic Wast

Co-digestion of two-phase olive-mill waste and cattle manure: Influence of solids content on process performance

The solids content is a key parameter in the development of anaerobic digestion as it can determine the proper operation and performance of the process. The influence of the total solids content on the mesophilic anaerobic co-digestion of two-phase olive-mill waste (2POMW) and cattle manure (CM) was investigated. Four different total solids (TS) concentrations, in a 75:25 mixture of 2POMW:CM, were studied in batch reactors of 2 L capacity: 10%TS (R10), 15%TS (R15), 20%TS (R20) and 28.6%TS (Reactor non-diluted). The methane yields and the organic matter removal efficiency for the reactor with 10 and 15% TS were significantly higher than in the reactors with a higher solids content (R20 and Rnd). The hydrolytic and acidogenic phases were not adversely affected by the total solid content since the concentration of volatile fatty acids (VFAs) increased as TS per- centage increased. However, a clear effect on the methanogenic phase was observed, which led to the accu- mulation of VFAs in the reactors R15, R20 and Rnd. Experimental results have shown that the best conditions correspond to the reactor containing 10% TS. The volatile solids and VFA removal in reactor R10 were 57.5% and 93.7% respectively. Moreover, the methane yield and the specific methane production were 35.80 LCH4/ kgVSadded and 82.51 LCH4/kgVSremoved respectivelyThis research has been co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economic Transformation, Industry, Knowledge and University of the Regional Government of Andalusia. Project reference: FEDER-UCA18-107460

Pre-composting of municipal solid wastes as enhancer of bio-hydrogen production through dark fermentation process

This study was focused on bio-hydrogen production from thermophilic dry anaerobic acidogenic co-digestion (55 °C and 20 % of total solids) of pre-composted mixtures of organic fraction of municipal solid waste (OFMSW) and food waste (FW). Three different mixture ratios of OFMSW:FW (80:20, 70:30 and 50:50) have been tested. The application of pre-composting improved the hydrolytic and acidogenic phases in the subsequent acidogenic co-digestion, reaching an increase in the bio-hydrogen production in the range of 45.4–46.7 %. In this sense, the best results were obtained for the pretreated mixture with the ratio 70:30, with 42.9 LH2/kg VSadded and 53.9 % of H2 in the biogas. Finally, the kinetic study has corroborated that pre-composting clearly enhances the kinetics of acidogenic fermentation of OFMSW and FW mixtures. In fact, the μmax and YP values for the pretreated mixtures have been increased by a 20 % and 33 % respectively

Start-up of the mesophilic anaerobic co-digestion of two-phase olive-mill waste and cattle manure using volatile fatty acids as process control parameter

In this work, the start-up and stabilization stages of mesophilic anaerobic co-digestion of 2POMW and CM in a semi-continuously fed stirred tank reactor (SSTR) were analyzed. Volatile fatty acids (VFAs) were monitored and used as the main control parameter for the start-up and stabilization stages, as well as to evaluate the potential inhibition episodes. The results showed that accumulation of propionic acid was the key factor in the inhibition of the methanogenic phase, leading to process imbalance. To avoid the problems associated with inhibition by high VFA concentrations, several reinoculations were performed using a suitable inoculum adapted to VFA degradation. The start-up phase was carried out in batch conditions for 97 days, reaching a final concentration of propionic acid of 12.77 mg/L. From that moment, the reactor was fed in a semi-continuous mode with a hydraulic retention time (HRT) of 40 days. A total period of 140 days was required to achieve a stable performance of the reactor with a methane productivity of 0.34 LCH4/LRd

Thermophilic Anaerobic Co-Digestion of Exhausted Sugar Beet Pulp with Cow Manure to Boost the Performance of the Process: The Effect of Manure Proportion

Sugar beet by-products are a lignocellulosic waste generated from sugar beet industry during the sugar production process and stand out for their high carbon content. Moreover, cow manure (CM) is hugely produced in rural areas and livestock industry, which requires proper disposal. Anaerobic digestion of such organic wastes has shown to be a suitable technology for these wastes valorization and bioenergy production. In this context, the biomethane production from the anaerobic co-digestion of exhausted sugar beet pulp (ESBP) and CM was investigated in this study. Four mixtures (0:100, 50:50, 75:25, and 90:10) of cow manure and sugar beet by-products were evaluated for methane generation by thermophilic batch anaerobic co-digestion assays. The results showed the highest methane production was observed in mixtures with 75% of CM (159.5 mL CH4/g VolatileSolids added). Nevertheless, the hydrolysis was inhibited by volatile fatty acids accumulation in the 0:100 mixture, which refers to the assay without CM addition. The modified Gompertz model was used to fit the experimental results of methane productions and the results of the modeling show a good fit between the estimated and the observed data

Mesophilic anaerobic co-digestion of two-phase olive-mill waste and cattle manure: Optimization of semi-continuous process

Anaerobic co-digestion of organic wastes is an effective technology for the management of two or more substrates with different characteristics. In this context, the main objective of this work was the optimization of biogas production for the treatment of a mixture of two-phase olive-mill waste (2POMW) and cattle manure (CM) (60:40 w/w) at mesophilic temperature range (35 degrees C). The effect of hydraulic retention time (HRT) on the performance and stability of the digestion process was studied. A decreasing series of HRTs in the range of 40-12 days was analyzed. The corresponding organic loading rates (OLR) were in the range 2.01-6.07 gVS/L(R)middotd. Pseudo steady-state operation of the reactor was established for HRTs between 40 and 15 days. For 15-days HRT, the maximum values of methane productivity (0.94 LCH4/L(R)middotd) and specific methane yield (0.52 LCH4/gVS(removed)) were obtained while total acidity (measured as acetic acid) in the effluent were < 150 mg/L, verifying process stability. In addition, the removal efficiencies of volatile solids (VS) and dissolved organic carbon (DOC) were 38 and 67 %, respectively. At 12-days HRT, decreases in methane production and organic matter removal efficiencies were observed, with values of 27 and 47 % for VS and DOC removal, respectively. Therefore, 12-days HRT was considered as inadequate for the anaerobic co-digestion of 2POMW and CM because a clear increase in volatile fatty acids was observed at the end of this period, leading to process destabilization and a decrease in biogas production

New criteria to determine the destabilization of the acidogenic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with mixed sludge (MS)

Effect of hydraulic retention time (HRT) on bio-hydrogen production from co-digestion of organic fraction of municipal solid waste (OFMSW) and mixed sludge (MS) in dry thermophilic conditions (55 °C and 20% total solids) was investigated. A decreasing sequence of six HRTs, from 2.9 to 0.8-days, was performed to evaluate the stability of the system and the influence of HRT on the organic matter solubilization, the daily hydrogen production (HP) and the specific hydrogen production (SHP). Best results were obtained operating at 1.2-days HRT: HP of 3.67 L H2/Lreactor/day, SHP of 33.8 mL H2/gVSadded and hydrogen percentage in biogas of 52.4%. However, HRTs lower than 1.2-days induce failure in the system due to an unbalance of the hydrolytic phase. This fact was corroborated through the evaluation of two indirect parameters, “non-solubilized carbon” (NSC) and “acidogenic substrate as carbon” (ASC), and the relationships of NSC/TOC and ASC/TOC