Search results for "paper industry"
showing 10 items of 413 documents
Removal of algae from biological cultures: a challenge for electrocoagulation?
2014
BACKGROUND In the search for novel technologies for the treatment of urban wastewater, combined anaerobic–algae membrane bioreactors have become a very interesting choice. Recovery of algae produced in these reactors has become the key point to obtain a good economic efficiency with this technology. In this work, electrocoagulation is studied as an alternative for the coarse removal of algae from a biological culture. RESULTS Results demonstrate that the electrochemical technology is a suitable technology for this purpose allowing the removal of more than 90% of the algae without modifying significantly the pH and with an operating cost below 0.04 € m−3. The same general trends are observed…
Influence of the initial acidification step on biogas production and composition
2014
Laboratory-scale experiments were carried out to evaluate the effect of initial acidification of feedstock consisting of different components on biogas production and composition. Feedstock containing different agricultural wastes, biomass, and microorganisms was collected from five full-scale biogas plants. Two continuously stirred tank reactors were used. The fermentation temperature was 37 °C. The pH value was adjusted to 6.0 in the first reactor at the beginning of the experiment, and an initial pH value of 7.0 was implemented after 48 H. The second reactor was used as a control reactor with a constant pH of 7.0. The experiment lasted a total of 7 days. In the reactors, the gas phase wa…
Influence of the methodology of inoculation in the performance of air-breathing microbial fuel cells
2017
In this work, four air-breathing microbial fuel cells (AB-MFC) were operated for 1 month in order to determine if the methodology of inoculation affects the steady-state performance of this type of MFCs. For this purpose, anaerobic and aerobic sludge were fed to two identical AB-MFCs without any external carbon source into a tight sealed environment during the first three days of start-up. For comparison purposes, other two AB-MFCs were operated mixing the initial sludge and an amount of sodium acetate as substrate. Results point out that the inoculation procedure does not affect the steady-state treatment capacity of the cells but it affects very seriously the production of electricity. On…
Influence of the initial sludge characteristics and acclimation on the longterm performance of double-compartment acetate-fed microbial fuel cells
2018
Abstract In this work, three double-compartment MFCs (DC-MFC) were operated for 1 month in order to compare their performances in terms of wastewater treatment capacity and electricity production and to get information about how this performance is influenced by the start-up procedure. To do this, they underwent different start-up procedures. One of them (aerobic-starved MFC) was inoculated with 100% fresh aerobic sludge, another (anaerobic-starved MFC) using 100% fresh anaerobic sludge, and finally a third one (aerobic-fed MFC) was inoculated using a mixture 10% fresh aerobic sludge and 90% synthetic wastewater (based on acetate). Then, from this start-up, the cells were operated exactly u…
Preliminary evaluation of biopolymers production by mixed microbial culture from citrus wastewater in a MBR system using respirometric techniques
2021
Abstract This preliminary study was aimed at evaluating the feasibility to produce biopolymers (BP) from citrus wastewater by mixed microbial culture in an anaerobic/aerobic membrane bioreactor (A/O-MBR). The activated sludge of the A/O-MBR was successfully enriched in microorganisms having a good capacity in producing intracellular biopolymers. The production of BP was found to be about 0.55 mgCOD mgCOD−1 using pure acetate at a concentration of 1000 mgCOD L−1. When using fermented wastewater, the conversion of acetate into BP product was 0.56 mgCOD mgCOD−1 in the test performed with C/N equal to 1000:1, whereas it was only 0.12 mgCOD mgCOD−1 in the test with C/N of 100:5. The results achi…
HEV Occurrence in Waste and Drinking Water Treatment Plants
2020
Hepatitis E virus (HEV), particularly zoonotic genotype 3, is present in environmental waters worldwide, especially in industrialized countries. Thus, monitoring the presence of HEV in wastewater treatment plants (WWTPs) is an emerging topic due to the importance of reusing water on a global level. Given the limited data, this study aimed to monitor the occurrence of HEV in influent and effluent water in waste- and drinking-water treatment plants (WWTPs and DWTPs). To this end, different procedures to concentrate HEV in influent and effluent water from WWTPs and DWTPs were initially evaluated. The evaluated procedures resulted in average HEV recoveries of 15.2, 19.9, and 16.9% in influent, …
Enzymatic Hydrolysis of Lignocellulose for Bioethanol Production
2017
Abstract The effect of temperature, time and amount of enzyme on hydrolysis of wheat straw lignocellulose remaining after furfural production was studied. The residual substrate was subjected to enzymatic hydrolysis at different temperatures — 45 °C, 50 °C and 55 °C. Hydrolysis time was 72 hours, and samples were taken every 24 hours. The maximum glucose yield (76.5% of the theoretically possible) was reached when hydrolysis temperature 50 °C was used. The production rate of glucose increased with a hydrolysis period of time. The yield of glucose significantly depended on the ratio of enzyme to substrate.
Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology
2016
Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5 mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S rat…
Economic analysis of the scale-up and implantation of a hollow fibre membrane contactor plant for nitrogen recovery in a full-scale wastewater treatm…
2021
[EN] Nitrogen recovery technologies such as the hollow fibre membrane contactor are now being developed. However, an economic analysis is needed prior to their full-scale application in wastewater treatment plants. The aim of this study was to analyse the economic and environmental aspects of scaling-up this method. To achieve it, a full-scale 40,000 m3·day¿1-wastewater treatment plant influent flow rate was simulated jointly with a membrane contactor plant to evaluate the minimum costs of optimum operating conditions of membrane contactors (pH, feed flow rate and membrane surface). The optimum conditions for treating 600 m3·day¿1 of reject water was found to be 10 pH, 0.08 m3·s¿1 feed flow…
The influence of solid retention time on IFAS-MBR systems: analysis of system behavior.
2018
A University of Cape Town Integrated Fixed-Film Activated Sludge Membrane Bioreactor (UCT-IFAS-MBR) pilot plant was operated at different values of the sludge retention time (SRT). Three SRTs were investigated at different durations: indefinitely, 30 and 15 days. The organic carbon, nitrogen and phosphorus removal, kinetic/stoichiometric parameters, membrane fouling tendency and sludge filtration properties were assessed. The findings showed that by decreasing the SRT, the pilot plant could maintain excellent carbon removal efficiencies throughout the experiments. In contrast, the biological carbon removal showed a slight nitrification and was slightly affected by the decrease of the SRT, s…