Anaerobic treatment of municipal wastewater using the UASB-technology

2007 ◽  
Vol 56 (10) ◽  
pp. 37-44 ◽  
Author(s):  
I. Urban ◽  
D. Weichgrebe ◽  
K.-H. Rosenwinkel
Keyword(s):  
Co2 Emission ◽  
Municipal Wastewater ◽  
Clean Energy ◽  
Anaerobic Treatment ◽  
Relevant Effect ◽  
Different Temperatures ◽  
High Concentrations ◽  
New Applications ◽  
Uasb Reactors ◽  
Positive Effect

The anaerobic treatment of municipal wastewater enables new applications for the reuse of wastewater. The effluent could be used for irrigation as the included nutrients are not affected by the treatment. Much more interesting now are renewable energies and the retrenchment of CO2 emission. With the anaerobic treatment of municipal wastewater, not only can the CO2 emission be reduced but “clean” energy supply can be gained by biogas. Most important for the sustainability of this process is the gathering of methane from the liquid effluent of the reactor, because the negative climate-relevant effect from the degassing methane is much higher than the positive effect from saving CO2 emission. In this study, UASB reactors were used with a flocculent sludge blanket for the biodegradation of the carbon fraction in the wastewater with different temperatures and concentrations. It could be shown that the positive effect is much higher for municipal wastewater with high concentrations in hot climates.

scholarly journals Influence of temperature on the performance of anaerobic treatment systems of municipal wastewater

Water SA ◽  
2018 ◽  
Vol 44 (2 April) ◽  
Author(s):  
Silvânia Lucas Dos Santos ◽  
Sílvia Raphaele Morais Chaves ◽  
Adrianus Van Haandel
Keyword(s):  
Experimental Investigation ◽  
Municipal Wastewater ◽  
Sewage Treatment ◽  
Poor Performance ◽  
Pilot Scale ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Organic Load ◽  
Anaerobic Sludge ◽  
Uasb Reactors

Anaerobic sewage treatment systems, especially upflow anaerobic sludge blanket (UASB) reactors, have found wide application over the past decades, particularly in regions with a warm climate. A low sewage temperature is generally considered as a factor contributing to poor performance, characterized by an increase of the COD fractions in the effluent and the generated sludge, and decreasing the fraction that is transformed into methane. An experimental investigation was carried out at pilot scale to establish the values of the three COD fractions for different values of temperature and the applied organic load. The sludge age of the anaerobic treatment, together with temperature, was identified as the main operational variable that affects the efficiency of anaerobic treatment. An empirical expression was derived for the values of the three factions as a function of these two variables. From the results of the experimental investigation it was apparent that there is no point in applying a sludge age of more than 100 d, when the reactor is near its best performance. An expression was derived to establish the hydraulic retention time for maximum digestion efficiency as a function of temperature, concentration and composition of organic material and sludge mass. It was established that the main limit to the sludge hold-up in UASB reactors treating sewage is not the sludge settleability, but rather the break-up of flocs leading to loss of small, poorly-settling particles.

Vacuum Operation for Overloaded Anaerobic Treatment Systems

1989 ◽  
Vol 21 (4-5) ◽  
pp. 87-95
Author(s):  
J. De Santis ◽  
A. A. Friedman
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Anaerobic Treatment ◽  
Optimum Operating ◽  
Operating Pressure ◽  
Simple Modification ◽  
Anaerobic Reactors ◽  
Fixed Film ◽  
Solids Retention ◽  
High Concentrations

Overloaded anaerobic treatment systems are characterized by high concentrations of volatile fatty acids and molecular hydrogen and poor conversion of primary substrates to methane. Previous experiments with fixed–film reactors indicated that operation with reduced headspace pressures enhanced anaerobic treatment. For these studies, four suspended culture, anaerobic reactors were operated with headspace pressures maintained between 0.5 and 1.0 atm and a solids retention time of 15 days. For lightly loaded systems (0.4 g SCOD/g VSS-day) vacuum operation provided minor treatment improvements. For shock organic loads, vacuum operation proved to be more stable and to support quicker recovery from upset conditions. Based on these studies and a companion set of bioassay tests, it was concluded that: (a) a loading rate of about 1.0 g SCOD/g VSS-day represents a practical loading limit for successful anaerobic treatment, (b) a headspace pressure of approximately 0.75 atm appears to be an optimum operating pressure for anaerobic systems and (c) simple modification to existing systems may provide relief for organically overloaded systems.

scholarly journals Migration from acrylonitrile butadiene styrene (ABS) polymer: swelling effect of food simulants compared to real foods

2021 ◽  
Author(s):  
Valeria Guazzotti ◽  
Annika Ebert ◽  
Anita Gruner ◽  
Frank Welle
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Polymer Swelling ◽  
Food Simulants ◽  
Diffusion Parameters ◽  
Compliance Testing ◽  
Diffusion Migration ◽  
Different Temperatures ◽  
Effect Of Food ◽  
High Concentrations ◽  
Butadiene Styrene

AbstractMaterials and articles made of acrylonitrile–butadiene–styrene (ABS) intended for contact with food must comply with the requirements of the European Plastic Regulation (EU) 10/2011, which lays down the food simulants and the time/temperature conditions to be applied for migration testing. Previous studies indicated that high concentrations of ethanol at temperatures above ambient may lead to swelling of ABS polymers resulting in increased migration. In this study migration kinetic data for a set of model substances at different temperatures were obtained using both food simulants stipulated in EU regulations and real food (milk, cream and olive oil). At the same time, the extent of polymer swelling was gravimetrically characterized after contact with simulants and different foods tested at several conditions to cover the majority of foreseeable applications of ABS. The obtained results confirmed that the use of high concentrations of ethanol–water, especially at high temperatures, causes the swelling of ABS polymers and results in significantly higher migration values compared to the tested foods as well as Tenax®. None of the real foods studied cause significant swelling of ABS. The widely used simulant 95% (v/v) aqueous ethanol proves not be suitable for compliance testing of ABS under the recommended conditions of Regulation (EU) 10/2011. Swelling of the polymer results in artificially higher diffusion coefficients or lower activation energies of diffusion. Migration prediction using polymer-specific diffusion parameters should therefore be considered to avoid over-conservative risk assessment for food contact materials and articles made of ABS.

scholarly journals Performance of Full-Scale Thermophilic Membrane Bioreactor and Assessment of the Effect of the Aqueous Residue on Mesophilic Biological Activity

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1754
Author(s):  
Maria Cristina Collivignarelli ◽  
Marco Carnevale Miino ◽  
Francesca Maria Caccamo ◽  
Marco Baldi ◽  
Alessandro Abbà
Keyword(s):  
Uptake Rate ◽  
High Strength ◽  
Acute Effect ◽  
Full Scale ◽  
A Value ◽  
Nitrogen Uptake Rate ◽  
High Concentrations ◽  
Input Load ◽  
Positive Effect ◽  
Sludge Production

To date, the management of high-strength wastewater represents a serious problem. This work aims to evaluate the performance on chemical pollutants and on sludge production of one of the two full-scale thermophilic membrane bioreactors (ThMBRs) currently operational in Italy, based on monitoring data of the last two and a half years. Removal yields on COD, N-NOx, non-ionic and anionic surfactants (TAS and MBAS), increased with the input load up to 81.9%, 97.6%, 94.7%, and 98.4%, respectively. In the period of stability, a very low value of sludge production (0.052 kgVS kgCOD−1) was observed. Oxygen uptake rate (OUR) tests allowed us to exclude the possibility that mesophilic biomass generally exhibited any acute inhibition following contact with the aqueous residues (ARs), except for substrates that presented high concentrations of perfluoro alkyl substances (PFAS), cyanides and chlorides. In one case, nitrifying activity was partially inhibited by high chlorides and PFAS concentration, while in another the substrate determined a positive effect, stimulating the phenomenon of nitrification. Nitrogen uptake rate (NUR) tests highlighted the feasibility of reusing the organic carbon contained in the substrate as a source in denitrification, obtaining a value comparable with that obtained using the reference solution with methanol. Therefore, respirometric tests proved to be a valid tool to assess the acute effect of AR of ThMBR on the activity of mesophilic biomass in the case of recirculation.

First Proof of Concept for Full-Scale, Direct, Low-Temperature Anaerobic Treatment of Municipal Wastewater

2021 ◽  
pp. 125786
Author(s):  
Anna Christine Trego ◽  
B. Conall Holohan ◽  
Ciara Keating ◽  
Alison Graham ◽  
Sandra O'Connor ◽  
...  
Keyword(s):  
Low Temperature ◽  
Municipal Wastewater ◽  
Anaerobic Treatment ◽  
Full Scale ◽  
Proof Of Concept

scholarly journals ENERGY PROPERTIES OF WOOD PARTICLES TORREFIED AT DIFFERENT TEMPERATURES

2017 ◽  
Vol 41 (4) ◽  
Author(s):  
Carlos Miguel Simões da Silva ◽  
Benedito Rocha Vital ◽  
Angélica de Cassia Oliveira Carneiro ◽  
Aylson Costa Oliveira ◽  
Solange Oliveira Araújo ◽  
...  
Keyword(s):  
Untreated Wood ◽  
Control Group ◽  
Fixed Carbon ◽  
Final Temperature ◽  
Heating Value ◽  
Physical Chemical ◽  
Wood Particles ◽  
Different Temperatures ◽  
Fixed Carbon Content ◽  
Positive Effect

ABSTRACT The objective of this study was to evaluate the effect of the final torrefaction temperature on the energy properties of wood. It was applied four treatments with three replicates, consisting of untreated wood particles and particles torrefied at temperatures of 170, 220 and 260ºC. Better physical, chemical and thermal properties of the particles were observed as a function of the torrefaction temperature. Comparing with the control group, the particles torrefied at the highest final temperature (260ºC) showed significant differences in bulk density - from 239 to 396kg/m3; the equilibrium moisture content changed from 12.3 to 5.7%; fixed carbon content - from 13.0 to 24.8%; heating value - from 4,465 to 4,945kcal/kg; and energy density - from 882 to 1,727Mcal/m3. It was concluded that torrefaction had a positive effect on the energy properties of the wood.

scholarly journals Investigation of Fatigue Behavior of ABS and PC-ABS Polymers at Different Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1818
Author(s):  
Andrea Mura ◽  
Alessando Ricci ◽  
Giancarlo Canavese
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Working Condition ◽  
Fatigue Behavior ◽  
Polymeric Materials ◽  
Cyclic Loads ◽  
Structural Components ◽  
Working Temperature ◽  
Different Temperatures ◽  
Positive Effect

Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.

The influence of chemical structure on the anaerobic catabolism of refractory compounds: a case study of instant coffee wastes

1994 ◽  
Vol 30 (12) ◽  
pp. 223-232 ◽  
Author(s):  
N. G. Azhar ◽  
D. C. Stuckey
Keyword(s):  
Industrial Effluent ◽  
Anaerobic Treatment ◽  
Instant Coffee ◽  
Waste Sample ◽  
Coffee Waste ◽  
Refractory Compounds ◽  
Methane Potential ◽  
Bioassay Technique ◽  
High Concentrations

Due to concerns about meeting the strict legislation currently in force, anaerobic treatment is being investigated for the treatment of a variety of waste streams. Instant coffee wastes are one type of industrial effluent that appears to be amenable to anaerobic digestion, and this paper presents some results on the biodegradation of this effluent. The method used was a batch bioassay technique known as the Biochemical Methane Potential assay (BMP), which gave 84% degradation of a composite coffee waste sample. Various fractions of the coffee waste revealed mixed degradation results mostly attributed to structural differences, with the liquid fractions being almost 60% degradable, and the solids filter cake fraction, containing most of the lignocellulosic material being only 9% degradable. Volatile fatty acid (VFA) analysis revealed high concentrations of formate being formed and subsequently degraded in the bioconversion process, and a possible role for formate production was postulated. Variations in structure did not appear to affect the route by which VFAs were produced. Bioconversion of 5-6 major classes of pure organic compounds thought to be potentially recalcitrant in coffee effluent was investigated to determine possible mechanisms of degradation, and the extent to which structural variation affected degradability. The phenolics and chlorogenic acids gave the highest degradation of 70% and 60% respectively, and the cyclic volatiles the least degradation at 40%.

Application of the UASB-Reactor for Anaerobic Treatment of Paper and Board Mill Effluent

1985 ◽  
Vol 17 (1) ◽  
pp. 61-75 ◽  
Author(s):  
L H A Habets ◽  
J H Knelissen
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Energy Savings ◽  
Hydraulic Retention Time ◽  
Waste Water Treatment ◽  
Anaerobic Treatment ◽  
Raw Material ◽  
Uasb Reactor ◽  
Seed Sludge ◽  
Uasb Reactors

Within the holding of Bührmann-Tetterode NV, 7 Dutch paper and board mills are operating, all of them using mainly waste paper as raw material. While three of them completely closed their watercircuits, two other mills put into practice biological waste water treatment namely anaerobic and anaerobic/aerobic. Number 6 is realising an anaerobic plant this year and for number 7 research is still being carried out, dealing with several unfavourable aspects. In September 1981 research for anaerobic treatment (UASB reactors) was started. After good results had been achieved on laboratory scale (301), further investigations were started on semitechnical scale (50 m3). In both cases the anaerobic seed sludge granulated after a while and loadings up to 20 kg COD/m3.d could be handled. COD-removal was 70 per cent, even when the hydraulic retention time was only 2.5 hours. In April 1983 a 70 m3 practical scale UASB reactor was started up at the solid board mill of Ceres. In October 1983 a full scale plant was started up at Papierfabriek Roermond. This plant consists of a 1,000 m3 UASB reactor and a 70 m3 gasholder. It has been designed and constructed by Paques BV and is used for pretreatment of effluent, in order to reduce the loading of the activated sludge plant. Besides energy savings on the oxygen input, about 1 million m3/year of biogas is being generated and is used for steamproduction. Both plants are working satisfactorily. Investment costs appeared to be relatively low. At Ceres, pay-out time is 1.5 year, while at Papierfabriek Roermond waste water treatment is cheaper than before, although capacity is doubled.

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