Optimal process configuration for anaerobic digestion with ozonation

2003 ◽  
Vol 48 (4) ◽  
pp. 85-96 ◽  
Author(s):  
R. Goel ◽  
T. Tokutomi ◽  
H. Yasui ◽  
T. Noike
Keyword(s):  
Anaerobic Digestion ◽  
Ozone Treatment ◽  
Anaerobic Sludge ◽  
Sludge Disposal ◽  
Sludge Digestion ◽  
Process Configuration ◽  
Ozone Dose ◽  
Attractive Option ◽  
Ozone Pretreatment

Economical source minimization of excess sludge production is an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for two different process configurations that combine oxidative ozone treatment with anaerobic sludge digestion are described. In the first configuration ozone pretreatment was combined with chemostat anaerobic digestion while in the second configuration ozone pre/post-treatments were combined with an anaerobic digester operated without solid removal. From the results of chemostat experiments, the ozone pretreatment solubilized around 19% and 37% of the solids at 0.015 and 0.05 gO3/gTS ozone dose respectively. The ozone pretreatment resulted in improved TVS reduction efficiencies and the degradation efficiencies were observed to depend on the applied ozone dose and system SRT. The TVS degradation efficiency for pre-ozonated sludge at an ozone dose of 0.05 gO3/gTS was 59% as compared to 31% for the control reactor fed with un-ozonated sludge. Test results with the second configuration indicated that overall TVS removal efficiencies for a process scheme with post-ozonation could be improved up to 85% with a minimum ozone dose of 0.045 gO3/gTVS-fed. However, since no solids (except that for sampling) were withdrawn in this configuration, the accumulated total solids in the reactors increased to 28 g/l to 30 g/l at pseudosteady state. The average specific methane recoveries were observed to be 0.36 l CH4/gTVS fed which were slightly lower than theoretically expected. Based on the experimental results, important points in the choice of process configuration are discussed.

Anaerobic digestion of excess activated sludge with ozone pretreatment

2003 ◽  
Vol 47 (12) ◽  
pp. 207-214 ◽  
Author(s):  
R. Goel ◽  
T. Tokutomi ◽  
H. Yasui
Keyword(s):  
Anaerobic Digestion ◽  
Ozone Treatment ◽  
Anaerobic Sludge ◽  
Methane Recovery ◽  
Sludge Disposal ◽  
Ozone Dose ◽  
Significant Difference ◽  
Attractive Option ◽  
Ozone Pretreatment

Source minimization of excess sludge production by economical means can be considered an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for a process that combines the oxidative ozone pretreatment with anaerobic sludge digestion are described. The ozone pretreatment solubilized around 19% and 37% of the solids at 0.015 and 0.05 gO3/gTS ozone dose. The solubilization ratios during ozonation did not show any significant difference for the sludge concentrations ranging from 1.8-2.6%. The TVS concentrations after ozone treatment were observed to be about 3% lower than the feed sludge concentrations suggesting only partial mineralization during ozonation. The ozone pretreatment resulted in improved solid reduction efficiencies during anaerobic digestion leading to higher methane recovery. The TVS removal efficiencies during anaerobic digestion were observed to increase by a maximum of 35-90% depending on the applied ozone dose during ozone pretreatment. The improvement in TVS degradation efficiency at different applied ozone doses correlated well with the extent of solubilization during ozonation. Long-term data also suggested that biomass acclimation to ozonated sludge was necessary before higher degradation efficiencies could be achieved.

scholarly journals Free ammonia pretreatment for anaerobic sludge digestion reduces the spread of antibiotic resistance

2020 ◽  
Author(s):  
Zehao Zhang ◽  
Huan Liu ◽  
Qilin Wang
Keyword(s):  
Antibiotic Resistance ◽  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Antibiotic Resistance Genes ◽  
Free Ammonia ◽  
Anaerobic Sludge ◽  
Sludge Disposal ◽  
Sludge Digestion ◽  
Gene Copies ◽  
First Time

AbstractSludge from the wastewater treatment plants (WWTPs) has been recognized as a reservoir of antibiotic resistance genes (ARGs). Free ammonia (FA, i.e. NH3-N) pretreatment has been demonstrated to be able to enhance anaerobic digestion, which is a widely used method for sludge treatment. However, the effect of combined FA pretreatment and anaerobic digestion on the fate of ARGs is still unknown. This study demonstrated for the first time that combined FA pretreatment (420 mg NH3-N/L for 24 h) and anaerobic digestion could reduce the abundances of the tested ARGs by 0.06 log10 gene copies/g TS (total solids) compared with the anaerobic digestion alone. Specifically, the experimental results showed that combined FA pretreatment and anaerobic digestion reduced the abundances of aac(6’)-Ib-cr, blaTEM, sul2, tetA, tetB and tetX by 0.07, 0.37, 0.09, 0.32, 0.24 and 0.59 log10 gene copies/g TS compared with anaerobic digestion alone. In contrast, combined FA pretreatment and anaerobic digestion slightly increased the abundance of tetG by 0.05 log10 gene copies/g TS compared with anaerobic digestion alone. In addition, FA pretreatment did not significantly affect the abundance of sul1 and tetM during anaerobic digestion. This study revealed that FA pretreatment for anaerobic digestion could potentially reduce the spread of antibiotic resistance from the sludge to soil (while agriculture reuse is used as the sludge disposal method), thereby protecting the environment and human health.

Case study on the implementation of deammonification for the process water treatment of Munich WWTPs

2012 ◽  
Vol 65 (10) ◽  
pp. 1895-1902 ◽  
Author(s):  
Rita Hilliges ◽  
Eberhard Steinle ◽  
Bernhard Böhm
Keyword(s):  
Water Treatment ◽  
Operating Costs ◽  
Process Water ◽  
Second Stage ◽  
Sludge Disposal ◽  
Sludge Digestion ◽  
High Investment ◽  
Flow Treatment

The two-staged WWTP ‘Gut Grosslappen’ has a capacity of 2 mio. PE. It comprises a pre-denitrification in the first stage using recirculation from the nitrifying second stage. A residual post-denitrification in a downstream sand filter is required in order to achieve the effluent standards. Presently the process water from sludge digestion is treated separately by nitrification/denitrification. Due to necessary reconstruction of the biological stages, the process water treatment was included in the future overall process concept of the WWTP. A case study was conducted comparing the processes nitritation/denitrititation and deammonification with nitrification/denitrification including their effect on the operational costs of the planned main flow treatment. Besides the different operating costs the investment costs required for the process water treatment played a significant role. Six cases for the process water treatment were compared. As a result, in Munich deammonification can only be recommended for long-term future developments, due to the high investment costs, compared with the nitritation/denitritation alternative realizable in existing tanks. The savings concerning aeration, sludge disposal and chemicals were not sufficient to compensate for the additional investment costs. Due to the specific circumstances in Munich, for the time being the use of existing tanks for nitritation/denitritation proved to be most economical.

Advantages of anaerobic digestion of sludge in microaerobic conditions

2010 ◽  
Vol 62 (2) ◽  
pp. 427-434 ◽  
Author(s):  
P. Jenicek ◽  
J. Koubova ◽  
J. Bindzar ◽  
J. Zabranska
Keyword(s):  
Anaerobic Digestion ◽  
Anaerobic Bacteria ◽  
Anaerobic Sludge ◽  
Digested Sludge ◽  
Methanogenic Activity ◽  
Sulphide Oxidation ◽  
Sludge Digestion ◽  
Sulphide Concentration ◽  
Microaerobic Conditions

The paper reviews results and experience of microaerobic experiments at both high and low sulphide concentrations and evaluates advantages and drawbacks of the anaerobic digestion of sludge in microaerobic conditions as regards biogas quality, digested sludge quality, organic pollutants biodegradability and methanogenic activity of biomass. The innovative microaerobic modification of the anaerobic sludge digestion technology was studied in both laboratory and full scale. Microaerobic conditions are obtained by dosing of a limited amount of the air into the liquid phase of the anaerobic digester. It was shown that anaerobic bacteria including methanogens can be active also in such system. In a mixed culture, even strict anaerobes can survive without inhibition, if the facultative microorganisms are able to consume the present oxygen quickly and fully. Until now, the microaerobic conditions were predominantly used for hydrogen sulphide removal from biogas. In the paper the role of the surplus oxygen was studied also at low sulphide concentration, when the oxygen is consumed in high extent for other processes beside sulphide oxidation.

Effects of phosphorus removal chemicals upon methane production during anaerobic sludge digestion

1986 ◽  
Vol 13 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Warren B. Kindzierski ◽  
Steve E. Hrudey
Keyword(s):  
Anaerobic Digestion ◽  
Ferric Chloride ◽  
Methane Production ◽  
Phosphorus Removal ◽  
Anaerobic Sludge ◽  
Methane Formation ◽  
Chemical Toxicity ◽  
Methane Generation ◽  
Sludge Digestion ◽  
Volatile Solids

Aluminum sulphate (alum) and ferric chloride are commonly employed to aid phosphorus removal in wastewater treatment. Previous studies have indicated that these chemical coagulants produce sludges that adversely affect anaerobic digestion. The objective of this study was to assess the magnitude of the effects chemical coagulants have upon methane generation in anaerobic digestion. Methane production was monitored and concentrations of aluminum or iron present during batch digestion of chemically precipitated sludge were measured.Both alum and ferric chloride addition to activated sludge produced a sludge that demonstrated reduced methane production in batch anaerobic digestion. Neither metal inhibited methanogenesis of an acetate supplement, suggesting that chemical toxicity was not a likely explanation for overall reductions in methane formation. Considering the experimental results and the findings of others, reduced methane generation is most likely caused by physical isolation of degradable substrate by the coagulant floc, which causes an overall reduction in conversion of sludge volatile solids to methane.

Energy self-sufficient sewage wastewater treatment plants: is optimized anaerobic sludge digestion the key?

2013 ◽  
Vol 68 (8) ◽  
pp. 1739-1744 ◽  
Author(s):  
P. Jenicek ◽  
J. Kutil ◽  
O. Benes ◽  
V. Todt ◽  
J. Zabranska ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Standard Energy

The anaerobic digestion of primary and waste activated sludge generates biogas that can be converted into energy to power the operation of a sewage wastewater treatment plant (WWTP). But can the biogas generated by anaerobic sludge digestion ever completely satisfy the electricity requirements of a WWTP with ‘standard’ energy consumption (i.e. industrial pollution not treated, no external organic substrate added)? With this question in mind, we optimized biogas production at Prague's Central Wastewater Treatment Plant in the following ways: enhanced primary sludge separation; thickened waste activated sludge; implemented a lysate centrifuge; increased operational temperature; improved digester mixing. With these optimizations, biogas production increased significantly to 12.5 m3 per population equivalent per year. In turn, this led to an equally significant increase in specific energy production from approximately 15 to 23.5 kWh per population equivalent per year. We compared these full-scale results with those obtained from WWTPs that are already energy self-sufficient, but have exceptionally low energy consumption. Both our results and our analysis suggest that, with the correct optimization of anaerobic digestion technology, even WWTPs with ‘standard’ energy consumption can either attain or come close to attaining energy self-sufficiency.

The use of the core–shell structure of zero-valent iron nanoparticles (NZVI) for long-term removal of sulphide in sludge during anaerobic digestion

2015 ◽  
Vol 17 (12) ◽  
pp. 2013-2021 ◽  
Author(s):  
Lianghu Su ◽  
Guangyin Zhen ◽  
Longjiang Zhang ◽  
Youcai Zhao ◽  
Dongjie Niu ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Iron Nanoparticles ◽  
Zero Valent Iron ◽  
Anaerobic Sludge ◽  
Core Shell ◽  
Long Term Effects ◽  
The Core ◽  
Core Shell Structure ◽  
Zero Valent Iron Nanoparticles

The long-term effects of NZVI on hydrogen sulphide removal in an anaerobic sludge digester were investigated.

Ozonation of sewage sludge prior to anaerobic digestion

2000 ◽  
Vol 42 (9) ◽  
pp. 175-178 ◽  
Author(s):  
M. Weemaes ◽  
H. Grootaerd ◽  
F. Simoens ◽  
A. Huysmans ◽  
W. Verstraete
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Anaerobic Sludge ◽  
Waste Sludge ◽  
Sludge Digestion ◽  
Novel Approach ◽  
Sediment Fraction ◽  
Anaerobic Sludge Digestion ◽  
Pre Treatment ◽  
Rate Limiting

Anaerobic digestion has traditionally been employed to reduce the mass and volume of waste sludge and to enhance the sludge dewaterability. In practice, anaerobic digestion of biosolids has a number of shortcomings, i.e. the low biodegradability of the microbial cells and the high retention times due to the rate limiting hydrolysis step. An oxidative sludge pre-treatment with ozone was therefore used to solubilize the organic compounds and increase their biodegradability. It is shown that the pre-treatment could significantly enhance anaerobic sludge digestion. Moreover, a novel approach in which the sludge was separated in a thickened sediment fraction and a supernatant was investigated. The sediment was digested anaerobically and the supernatant was treated aerobically. The overall COD-removal efficiency of the biosolids was 72%.

Enhanced Anaerobic Digestion of Sewage Sludge by Addition of Food Waste

2013 ◽  
Vol 777 ◽  
pp. 139-142
Author(s):  
Li Han ◽  
Ru Ying Li ◽  
Min Ji
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Removal Efficiency ◽  
Food Waste ◽  
Methane Yield ◽  
Anaerobic Sludge ◽  
Sludge Digestion ◽  
Vs Removal ◽  
Anaerobic Sludge Digestion ◽  
Mesophilic Condition

In order to improve the methane yield and removal efficiency of organic matters in anaerobic sludge digestion, effects of addition of food waste were investigated at mesophilic condition. Results showed that the optimal TS ratio between sewage sludge and food waste was 4:1, with a methane yield of 592.7 ml/g-VS, methane content of 66.84% and the VS removal efficiency of 31%, which were 47%, 50% and 55% higher than those of sole sludge digestion, respectively.

Improving products of anaerobic sludge digestion by microaeration

2013 ◽  
Vol 69 (4) ◽  
pp. 803-809 ◽  
Author(s):  
P. Jenicek ◽  
C. A. Celis ◽  
L. Krayzelova ◽  
N. Anferova ◽  
D. Pokorna
Keyword(s):  
Oxygen Demand ◽  
Anaerobic Sludge ◽  
Digested Sludge ◽  
Sludge Digestion ◽  
Soluble Chemical Oxygen Demand ◽  
Long Term Monitoring ◽  
Anaerobic Sludge Digestion ◽  
Term Monitoring

Biogas, digested sludge and sludge liquor are the main products of anaerobic sludge digestion. Each of the products is influenced significantly by specific conditions of the digestion process. Therefore, any upgrade of the digestion technology must be considered with regard to quality changes in all products. Microaeration is one of the methods used for the improvement of biogas quality. Recently, microaeration has been proved to be a relatively simple and highly efficient biological method of sulfide removal in the anaerobic digestion of biosolids, but little attention has been paid to comparing the quality of digested sludge and sludge liquor in the anaerobic and microaerobic digestion and that is why this paper primarily deals with this area of research. The results of the long-term monitoring of digested sludge quality and sludge liquor quality in the anaerobic and microaerobic digesters suggest that products of both technologies are comparable. However, there are several parameters in which the ‘microaerobic’ products have a significantly better quality such as: sulfide (68% lower) and soluble chemical oxygen demand (COD) (33% lower) concentrations in the sludge liquor and the lower foaming potential of the digested sludge.

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