Soft sensor for substrate characterization through the reverse application of the ADM1 model for anaerobic digestion plant operations.

Accurately characterizing the substrate used in anaerobic digestion is crucial for predicting the biogas plant's performance. This issue makes particularly challenging the application of modeling in codigestion plants. In this work, a novel methodology called substrate prediction module (SPM) has been developed and tested, using virtual codigestion data.

Comprehensive ADM1 Extensions to Tackle Some Operational and Metabolic Aspects in Anaerobic Digestion.

Modelling in anaerobic digestion will play a crucial role as a tool for smart monitoring and supervision of the process performance and stability. By far, the Anaerobic Digestion Model No. 1 (ADM1) has been the most recognized and exploited model to represent this process.

New findings on the anaerobic co-digestion of thermally pretreated sludge and food waste: laboratory and pilot-scale studies.

Co-digestion of thermally pretreated sewage sludge with food waste is an innovative strategy that could improve the balance and availability of nutrients needed to increase the efficiency of anaerobic digestion in terms of biogas production. In this context, the aim of this research was to evaluate the impact of different proportions of sewage sludge/food waste in laboratory- and pilot-scale reactors. Special focus was placed on the impact of the variability of food waste composition on the behaviour of the pilot digester.

Exploitation of the ADM1 in a XXI century wastewater resource recovery facility (WRRF): The case of codigestion and thermal hydrolysis.

The aim of this study is to test the capability of the anaerobic digestion model n1 (ADM1) to reproduce data from full-scale digesters operated in a wastewater resource recovery facility (WRRF) where both thermal hydrolysis and codigestion with industrial waste are carried out. Furthermore, the potential uses of the model in a WRRF are also described, with particular relevance for plant engineers/operators. The model capability was calibrated and validated with data from full-scale digesters from the Mapocho-Trebal WRRF (Biofactoría) in Santiago, Chile.

Making sense of parameter estimation and model simulation in bioprocesses.

Most articles that report fitted parameters for kinetic models do not include meaningful statistical information. This study demonstrates the importance of reporting a complete statistical analysis and shows a methodology to perform it, using functionalities implemented in computational tools. As an example, alginate production is studied in a batch stirred-tank fermenter and modeled using the kinetic model proposed by Klimek and Ollis (1980).

Assessing the stability of anaerobic co-digestion in the context of a WWTP with thermal pre-treatment of sewage sludge. Case study in Chile.

In this study, beverage wastewater (BW) and extended aeration sewage sludge were assessed as co-substrates with both mixed sludge and thermally hydrolyzed sludge as substrates in an anaerobic codigestion (AcoD) process. The methodology is an integrated methodology that comprises a batch test (BMP) and semicontinuous reactor along with microbial diversity analysis. The results showed that in batch conditions, neither significant synergistic nor antagonistic effects were observed on the maximum potential (P) due to the cosubstrates presence.

Addressing the synergy determination in anaerobic co-digestion and the inoculum activity impact on BMP test.

Anaerobic mono-digestion and co-digestion are nowadays widely used in wastewater treatment plants (WWTP). However, the data processing of the conventional biochemical potential test (BMP) carried out to assess potential substrates should be enhanced to reduce the uncertainty of the results. In this study, two methodologies aiming to improve the data processing in anaerobic digestion studies were proposed.

Comparison of performance in an anaerobic digestion process: one-reactor vs two-reactor configurations.

The present work compares two types of configurations for a two-reaction (acidogenesis and methanogenesis) anaerobic digestion model. These configurations are as follows: (i) a single bioreactor, where the acidogenesis and methanogenesis reactions occur inside and, (ii) two bioreactors connected sequentially, where each reaction occurs separately in each reactor. The mathematical models that describe the mentioned configurations are analyzed at steady state, comparing the following criteria: the stability of the processes (stability properties of desired equilibria) and soluble organic matter removal performance (substrate levels at steady states), concluding that separation of the reactions in two bioreactors does not improve the stability of the process nor the soluble organic matter removal capacity, unless the improvement of the growth functions of both microorganism populations is considerably important at the moment of separating them into two reactors.

Mathematical modelling of in-situ microaerobic desulfurization of biogas from sewage sludge digestion.

Microaeration can be used to cost-effectively remove HS from the biogas generated in anaerobic digesters. This study is aimed at developing and validating an extension of the Anaerobic Digestion Model n°1 capable of incorporating the main phenomena which occurs during microaeration. This innovative model was implemented and tested with data from a pilot scale digester microaerated for ∼ 200 d.

A need for a standardization in anaerobic digestion experiments? Let's get some insight from meta-analysis and multivariate analysis.

An important variability in the experimental results in anaerobic digestion lab test has been reported. This study presents a meta-analysis coupled with multivariate analysis aiming to assess the impact of this experimental variability in batch and continuous operation at mesophilic and thermophilic anaerobic digestion of waste activated sludge. An analysis of variance showed that there was no significant difference between mesophilic and thermophilic conditions in both continuous and batch conditions.

Modelling of an anaerobic plug-flow reactor. Process analysis and evaluation approaches with non-ideal mixing considerations.

This study shows the implementation of the Anaerobic Digestion Model (ADM1) in an anaerobic plug-flow reactor (PFR) with two approaches based on the use of consecutive continuous stirred tank reactors (CSTR) connected in serie for considering non-ideal mixing. The two-region (TR) model splits each CSTR into two regions, while the particulate retention (PR) model adds a retention parameter. The models were calibrated and validated based on experimental data from a bench-scale reactor treating cow manure.

Effect of inoculum on the anaerobic digestion of food waste accounting for the concentration of trace elements.

The production of renewable energy in the form of methane from the anaerobic digestion (AD) of food waste (FW) varies depending on factors such as the quantity and quality of the inoculum. This research evaluated the influence of trace elements (Ca, K, Fe, Zn, Al, Mg, Co, Ni, and Mo) present in inoculum from different sources (wastewater treatment plants (WWTPs): 2 agro-industrial WWTPs and 1 municipal WWTP) on the AD of FW. This study found that the source of the inoculum determines the content of macronutrients and trace elements, which can alter the requirements of the AD process and therefore affect methane production.

Thermochemical pretreatment and anaerobic digestion of dairy cow manure: Experimental and economic evaluation.

The aim of this study was to assess technically and economically the application thermochemical pretreatment in the anaerobic digestion of dairy cow manure. After selecting the optimum substrate to inoculum (S/I) ratio in a preliminary BMP test, the following tests compared 20 different pretreatment conditions varying temperature (100 and 37°C), exposure time (5 and 30min and 12 and 24h) and chemical doses (0.5, 2, 6 and 10% of HCl or NaOH).

From pre-treatment toward inter-treatment. Getting some clues from sewage sludge biomethanation.

The conventional application of thermal pretreatment of sewage sludge has been to apply it prior to the anaerobic digestion. In this study, the thermal treatment of the digestate was assessed at lab-scale under several temperature and time conditions. Biochemical methane potential (BMP) tests were set up to evaluate the methane production kinetic by using the Gompertz modified and the first order equation.

Impact of milling, enzyme addition, and steam explosion on the solid waste biomethanation of an olive oil production plant.

Anaerobic digestion is a consolidated bioprocess which can be further enhanced by incorporating an upstream pretreatment unit. The olive oil production produces a large amount of solid waste which needs to be properly managed and disposed. Three different pretreatment techniques were evaluated in regard to their impact on the anaerobic biodegradability: manual milling of olive pomace (OP), enzyme maceration, direct enzyme addition, and thermal hydrolysis of two-phase olive mill waste.

Anaerobic biodegradability of fish remains: experimental investigation and parameter estimation.

The generation of organic waste associated with aquaculture fish processing has increased significantly in recent decades. The objective of this study is to evaluate the anaerobic biodegradability of several fish processing fractions, as well as water treatment sludge, for tilapia and sturgeon species cultured in recirculated aquaculture systems. After substrate characterization, the ultimate biodegradability and the hydrolytic rate were estimated by fitting a first-order kinetic model with the biogas production profiles.

Simplified mechanistic model for the two-stage anaerobic degradation of sewage sludge.

Two-phase anaerobic systems are being increasingly implemented for the treatment of both sewage sludge and organic fraction of municipal solid waste. Despite the good amount of mathematical models in anaerobic digestion, few have been applied in two-phase systems. In this study, a three-reaction mechanistic model has been developed, implemented and validated by using experimental data from a long-term anaerobic two-phase (TPAD) digester treating sewage sludge.

A methodology for a quantitative interpretation of DGGE with the help of mathematical modelling: application in biohydrogen production.

Molecular biology techniques provide valuable insights in the investigation of microbial dynamics and evolution. Denaturing gradient gel electrophoresis (DGGE) analysis is one of the most popular methods which have been used in bioprocess assessment. Most of the anaerobic digestion models consider several microbial populations as state variables.

ADM1 calibration using BMP tests for modeling the effect of autohydrolysis pretreatment on the performance of continuous sludge digesters.

Improving anaerobic digestion of sewage sludge through pretreatment techniques is a suitable solution for better sludge management. In this sense, modeling may present itself as an important tool to assess and predict process performance and pretreatment effects. In this study, the feasibility of using biochemical methane potential (BMP) tests data for calibrating the Anaerobic Digestion Model No.

Long-term hydrolytic capacity evaluation of a thermophilic anaerobic digester treating sewage sludge.

This study presents an evaluation of the hydrolytic activity of a continuous thermophilic anaerobic reactor in long-term operation. The hydrolytic coefficient was estimated by fitting a three-reaction model of the anaerobic digestion process with experimental data obtained from a pilot thermophilic digester operated for about 2 years. The model fitting and the cross-validation indicate that this model can represent the behavior of the system in a proper way; moreover, the results show a variation of the hydrolytic capacity of the system throughout the evaluation period.

Identification in an anaerobic batch system: global sensitivity analysis, multi-start strategy and optimization criterion selection.

Several mathematical models have been developed in anaerobic digestion systems and a variety of methods have been used for parameter estimation and model validation. However, structural and parametric identifiability questions are relatively seldom addressed in the reported AD modeling studies. This paper presents a 3-step procedure for the reliable estimation of a set of kinetic and stoichiometric parameters in a simplified model of the anaerobic digestion process.

Model selection, identification and validation in anaerobic digestion: a review.

Anaerobic digestion enables waste (water) treatment and energy production in the form of biogas. The successful implementation of this process has lead to an increasing interest worldwide. However, anaerobic digestion is a complex biological process, where hundreds of microbial populations are involved, and whose start-up and operation are delicate issues.

Anaerobic sequencing batch reactor as an alternative for the biological treatment of wine distillery effluents.

The goal of this study was to assess the effect of different modes of operation and configurations of Anaerobic Sequencing Batch Reactors (ASBRs) treating phenolic wastewater. Several lab-scale reactors were used in the mesophilic range. The reactors were fed with synthetic wastewater with a COD of 5 g/L using phenol as a carbon source (variable concentration) and glucose as a co-substrate.