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.

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.

scholarly journals Recognition of the key chemical constituents of sewage sludge for biogas production

RSC Advances ◽  
2017 ◽  
Vol 7 (4) ◽  
pp. 2033-2037 ◽  
Author(s):  
Xiaohu Dai ◽  
Ying Xu ◽  
Yiqing Lu ◽  
Bin Dong
Keyword(s):  
Organic Matter ◽  
Sewage Sludge ◽  
Silica Particle ◽  
Biogas Production ◽  
Chemical Constituents ◽  
Anaerobic Sludge ◽  
Key Factors ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Biodegradable Organic Matter

The easy biodegradable organic matter, non-biodegradable organic matter, metal ions, and micron-sized silica particle and their interactions were the key factors for limiting the biogas production from anaerobic sludge digestion.

scholarly journals THE IMPACT OF CHEMICAL PHOSPHORUS REMOVAL ON THE PROCESS OF ANAEROBIC SLUDGE DIGESTION

2010 ◽  
Vol 2 (5) ◽  
pp. 71-74
Author(s):  
Svetlana Ofverstrom ◽  
Ieva Sapkaitė ◽  
Regimantas Dauknys
Keyword(s):  
Anaerobic Digestion ◽  
Phosphorus Removal ◽  
Biogas Production ◽  
Anaerobic Sludge ◽  
Primary Sludge ◽  
Sludge Digestion ◽  
Volatile Solids ◽  
Anaerobic Sludge Digestion ◽  
Gas Volume ◽  
The Impact

The paper investigates the efficiency of the mixture of primary sludge and excess activated sludge in Vilnius WWTP with reference to the anaerobic digestion process. Sludge digestion was carried out under laboratory conditions using anaerobic sludge digestion model W8 (Armfield Ltd., UK). Laboratory analyses consist of two periods – the anaerobic digestion of the un-dosed and Fe-dosed sludge mixture. The results of digestion were processed using the methods of statistical analysis. The findings showed reduction in volatile solids approx. by 6% when dosing min FeCl3·6H2O and 15% when dosing max FeCl3·6H2O into feed sludge. Gas volume produced during the digestion of the un-dosed sludge was 90–160 ml/d and 60–125 ml/d in min Fe-dosed sludge and 45-95 ml/d. Also, correlation between VS loadings and biogas production was found. A rise in VS loading from 0,64 g/l/d to 1,01 g/l/d increased biogas production from 90 ml/d to 140–160 ml/d.

Aerobic Thermophilic Stabilization of Sludge versus Anaerobic Digestion and Other Kinds of Sludge Treatment at Middle-Sized Plants with Respect to Power Conservation and Economy

1982 ◽  
Vol 14 (6-7) ◽  
pp. 727-738
Author(s):  
P Wolf
Keyword(s):  
Anaerobic Digestion ◽  
Economic Benefit ◽  
Energy Recovery ◽  
Sewage Treatment Plant ◽  
Anaerobic Sludge ◽  
Process Conditions ◽  
Sludge Treatment ◽  
Capital Costs ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion

Operating data concerning energy balances are collected by a state bureau from a sewage treatment plant with aerobic–thermophilic stabilization and also from plants with anaerobic sludge digestion and energy recovery. On the basis of this data power and heat balances as well as cost–benefit–calculations have been obtaineu for treatment plants of different sizes with different biological and sludge treatment processes. In spite of high and rising energy costs in plants utilizing the aerobic-thermophilic stabilization process the results show an overall economic benefit for this process at small and middle-sized treatment plants compared to those utilizing anaerobic sludge digestion. The evaluation of data indicates that this economic benefit is due to high capital costs and little efficiency of energy recovery under process conditions at small and middle-sized plants applying anaerobic digestion.

Fate ofCryptosporidiumoocysts,Giardiacysts, and microbial indicators during wastewater treatment and anaerobic sludge digestion

1999 ◽  
Vol 45 (3) ◽  
pp. 257-262 ◽  
Author(s):  
Christian Chauret ◽  
Susan Springthorpe ◽  
Syed Sattar
Keyword(s):  
Wastewater Treatment ◽  
Clostridium Perfringens ◽  
Heterotrophic Bacteria ◽  
The Other ◽  
Anaerobic Sludge ◽  
Somatic Coliphages ◽  
Aerobic Wastewater Treatment ◽  
Sludge Digestion ◽  
Cryptosporidium Oocysts ◽  
Anaerobic Sludge Digestion

The extent of reduction in selected microorganisms was tested during both aerobic wastewater treatment and anaerobic digestion of sludge at the wastewater treatment plant in Ottawa to compare the removal of two encysted pathogenic protozoa with that of microbial indicators. Samples collected included the raw wastewater, the primary effluent, the treated wastewater, the mixed sludge, the decanted liquor, and the cake. All of the raw sewage samples were positive for Cryptosporidium oocysts and Giardia cysts, as well as for the other microorganisms tested. During aerobic wastewater treatment (excluding the anaerobic sludge digestion), Cryptosporidium and Giardia were reduced by 2.96 log10and 1.40 log10, respectively. Clostridium perfringens spores, Clostridium perfringens total counts, somatic coliphages, and heterotrophic bacteria were reduced by approximately 0.89 log10, 0.96 log10, 1.58 log10, and 2.02 log10, respectively. All of the other microorganisms were reduced by at least 3.53 log10. Sludge samples from the plant were found to contain variable densities of microorganisms. Variability in microbial concentrations was sometimes great between samples, stressing the importance of collecting a large number of samples over a long period of time. In all cases, the bacterial concentrations in the cake (dewatered biosolids) samples were high even if reductions in numbers were observed with some bacteria. During anaerobic sludge digestion, no statistically significant reduction was observed for Clostridium perfringens, Enterococcus sp., Cryptosporidium oocysts, and Giardia cysts. A 1-2 log10reduction was observed with fecal coliforms and heterotrophic bacteria. However, the method utilized to detect the protozoan parasites does not differentiate between viable and nonviable organisms. On the other hand, total coliforms and somatic coliphages were reduced by 0.35 log10and 0.09 log10, respectively. These results demonstrate the relative persistence of the protozoa in sewage sludge during wastewater treatment.Key words: Cryptosporidium, Giardia, indicators, wastewater, sludge.

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