Search results for "batch reactor"

A methodology for sequencing batch reactor identification with artificial neural networks: A case study

2009

This paper presents a systematic methodology based on the application of artificial neural networks for sequencing batch reactor (SBR) identification. The SBR is a fill-and-draw biological wastewater technology, which is specially suited for nutrient removal. The proposed approach makes optimal use of the available data during the training stage and it is aimed at achieving high generalization ability. For this purpose, a wide range of experimental conditions, including different solids retention times and influent characteristics, has been used. The methodology is successfully applied to develop a soft-sensor for monitoring a laboratory-scale SBR operated for enhanced biological phosphorus…

REMOVAL OF AN ORGANIC REFRACTORY COMPOUND BY PHOTOCATALYSIS IN BATCH REACTOR - KINETIC STUDIES

2015

An extension of ASM2d including pH calculation

2003

This paper presents an extension of the Activated Sludge Model No. 2d (ASM2d) including a chemical model able to calculate the pH value in biological processes. The developed chemical model incorporates the complete set of chemical species affecting the pH value to ASM2d describing non-equilibrium biochemical processes. It considers the system formed by one aqueous phase, in which biochemical processes take place, and one gaseous phase, and is based on the assumptions of instantaneous chemical equilibrium under liquid phase and kinetically governed mass transport between the liquid and gas phase. The ASM2d enlargement comprises the addition of every component affecting the pH value and an i…

Monitoring pH and electric conductivity in an EBPR sequencing batch reactor

2004

This paper presents laboratory-scale experimentation carried out to study enhanced biological phosphorus removal. Two anaerobic aerobic (A/O) sequencing batch reactors (SBR) have been operated during more than one year to investigate the information provided by monitoring pH and electric conductivity under stationary and transient conditions. Continuous measurements of these parameters allow detecting the end of anaerobic phosphorus release, of aerobic phosphorus uptake and of initial denitrification, as well as incomplete acetic acid uptake. These results suggest the possibility of using pH and electric conductivity as control parameters to determine the length of both anaerobic and aerobi…

Greenhouse gases from sequential batch membrane bioreactors: A pilot plant case study

2016

Abstract The paper reports the results of nitrous oxide (N 2 O) emissions from aerobic and anoxic tank of a Sequential Batch Membrane Bioreactor (SB-MBR) pilot plant. The influence of salinity variation on N 2 O emission was analyzed by gradually increasing the inlet salt concentration from 0 to 10 g NaCl L −1 . The observed results showed that the N 2 O concentration of the gaseous samples was strongly influenced by the salt concentration. This result was likely related to a worsening of the nitrification activity due to the effect of salinity on autotrophic bacteria. Dissolved oxygen concentration and salinity were found to be the key factors affecting N 2 O concentration in the gaseous s…

Performances of a granular sequencing batch reactor (GSBR).

2007

Aerobic granulation in sequencing batch reactors is widely reported in literature and in particular in SBAR (Sequencing batch airlift reactor) configuration, due to the high localised hydrodynamic shear forces that occur in this type of configuration. The aim of this work was to observe the phenomenon of the aerobic granulation and to confirm the excellent removal efficiencies that can be achieved with this technology. In order to do that, a laboratory-scale plant, inoculated with activated sludge collected from a conventional WWTP, was operated for 64 days: 42 days as a SBAR and 22 days as a SBBC (sequencing batch bubble column). The performances of the pilot plant showed excellent organic…

Relating ions concentration variations to conductivity variations in a sequencing batch reactor operated for enhanced biological phosphorus removal

2006

In this paper a deterministic relationship between ionic conductivity and phosphorus concentration variations in an enhanced biological phosphorus removal (EBPR) process is established. Conductivity shows a strong correlation with phosphorus in both anaerobic and aerobic stages, increasing or decreasing when phosphorus is released or taken up, respectively. Since the end of these processes can be detected by examining the conductivity profile in a cycle, useful information on the EBPR performance and stability is available. This information can be used for adjusting the length of the anaerobic and aerobic stages. Therefore, online process control based on inexpensive and easy to maintain se…

INFLUENCE OF THE EXPERIMENTAL SYSTEM AND OPTIMIZATION OF THE SELECTIVITY FOR THE ELECTROCARBOXYLATION OF CHLOROACETONITRILE TO CYANOACETIC ACID

2004

The electrocarboxylation of chloroacetonitrile (ClACN) to cyanoacetic acid in undivided cells equipped with sacrificial anodes was investigated both in a bench-scale electrochemical batch reactor and in a continuous batch recirculation reaction system equipped with a parallel-plate electrochemical cell. Selectivity and faradaic yields higher than 90% were obtained by working under anhydrous conditions with low halide concentrations and at more negative potentials. It was found that the instantaneous selectivity in the carboxylate compound depends mainly on the [CO 2 ]/[ClACN] ratio at high substrate concentration and is close to 100% for low ClACN concentration. These results were consisten…

Transesterification of rapeseed oil over acid resins promoted by supercritical carbon dioxide

2011

The methanolysis of rapeseed oil catalyzed by commercial styrene-divinylbenzene macroporous acid resins was performed in a batch reactor at 100-140 °C and 10-46 MPa to study the effect of supercritical carbon dioxide (scCO2) on the performances of the process. Reaction temperatures of 120-140 °C were necessary to obtain high enough yields of fatty acid methyl esters. Upon addition of scCO2 faster transesterification kinetics was obtained also at the lowest investigated operating pressure (10-11 MPa), working in two fluid phase systems. Experiments performed changing the reaction time indicated that most of the esters were formed during the first 3 h. When the pressure was increased at 38-46…

Microwave-assisted catalytic esterification of α-glucoisosaccharino-1,4-lactone with tall oil fatty acids

2016

Background: Carbohydrates-rich materials are partly degraded during alkaline kraft pulping into a complex mixture of aliphatic carboxylic acids consisting of α-glucoisosaccharinic acid as one of the main acids. On the other hand, crude tall oil, containing significant amounts fatty acids, is obtained as a by-product from kraft pulping. One interesting novel approach is to utilize chemically both these side-streams by producing renewable surfactants from aliphatic carboxylic acids and fatty acids via esterification. Results: In this paper, lauric (C12:0) and oleic (C18:1) acids as well as a mixture of tall oil fatty acids were esterified with α-glucoisosaccharino-1,4-lactone in a microwave-a…