Fermentation Of Sewage Sludge Research Articles

Biogas from waste and renewable resources: an introduction

Preface. Abbreviations. Acknowledgement. Part I General thoughts about energy supply. 1 Energy supply - today and in the future. 1.1 Primary energy sources. 1.2 Secondary energy sources. 1.3 End-point energy sources. 1.4 Effective energy. 2 Energy supply in the future - scenarios. 2.1 Amount of space. 2.2 Potential yield from biomass. 2.3 Technical potential. 2.4 Economic potential. 2.5 Realizable potential. 3 History and status to date in Europe. 3.1 First attempts at using biogas. 3.2 Second attempts at using biogas. 3.3 Third attempts at applying biogas. 3.4 Status to date and perspective in Europe. 4 History and status to date in other countries. 4.1 History and status to date in China. 4.2 History and status to date in India. 4.3 Status to date in Latin America. 4.4 Status to date in the CIS states. 5 General aspects of the recovery of biomass in the future. Part II Substrate and biogas. 1 Biogas. 1.1 Biogas compared to other methane-containing gases. 1.2 Detailed overview of biogas components. 2 Substrates. 2.1 Liquid manure and co-substrates. 2.2 Bio waste from collections of residual waste and trade waste similar to domestic waste. 2.3 Landfi ll for residual waste. 2.4 Sewage sludge and co-substrate. 2.5 Industrial waste water. 2.6 Waste grease or fat. 2.7 Cultivation of algae. 2.8 Plankton. 2.9 Sediments in the sea. 2.10 Wood, straw. 3 Evaluation of substrates for biogas production. 4 Benefi ts of a biogas plant. Part III Formation of biogas. 1 Biochemical reaction. 2 Biology. 2.1 Bioreactions. 2.2 Process parameters. 3 Bacteria participating in the process of degradation . 3.1 Hydrolyzing genera. 3.2 Acidogenic genera. 3.3 Acetogenic genera. 3.4 Methanogenics. 3.5 Methanotropic species. Part IV Laws and guidelines concerning biogas plants. 1 Guidelines and regulations. 1.1 Construction of plants. 1.2 Utilized biomass. 1.3 Biomass to be used preferentially. 1.4 Distribution of the residues. 1.5 Feeding biogas to the gas network. 1.6 Risk of explosion. 1.7 Risk of fire. 1.8 Harmful exhaust gases. 1.9 Noise protection. 1.10 Prevention of injuries. 1.11 Protection from water. 2 Building a biogas plant. 2.1 Feasibility study. 2.2 Preliminary planning. 2.3 The construction process. 3 Financing. Part V Process engineering. 1 Parts of biogas plants. 1.1 Tanks and reactors. 1.2 Equipment for tempering the substrate. 1.3 Thermal insulation. 1.4 Piping system. 1.5 Pump system. 1.6 Measurement, control, and automation technology. 1.7 Exhaust air cleaning. 2 Area for the delivery and equipment for storage of the delivered biomass. 3 Process technology for the upstream processing. 3.1 Adjustment of the water content. 3.2 Removal of disturbing/harmful substances. 3.3 Comminution. 3.4 Hygienization. 3.5 Disintegration. 3.6 Feeding. 4 Fermentation technology. 4.1 Batchwise and continuous processes without separators. 4.2 Existing installations by different suppliers. 4.3 Installation with substrate dilution and subsequent water separation. 4.4 Installation with biomass accumulation. 4.5 Plants with separation of non-hydrolyzable biomass. 4.6 Residue storage tank and distribution. 5 Special plant installations. 5.1 Combined fermentation of sewage sludge and bio waste. 5.2 Bio waste plants. 5.3 Purifi cation of industrial waste water. Part VI Biogas to energy. 1 Gas pipelines. 2 Biogasholder. 2.1 Biogasholder types. 2.2 Gas flares. 3 Gas preparation. 3.1 Removal of hydrogen sulfide. 3.2 Removal of the carbon dioxide. 3.3 Removal of oxygen. 3.4 Removal of water. 3.5 Removal of ammonia. 3.6 Removal of siloxanes. 4 Liquefaction or compression of the biogas. 4.1 Liquefaction. 4.2 Compression. 5 Utilization of biogas for the generation of electric power and heat. 5.1 Supply of current to the public electricity network. 5.2 Heat. 5.3 Combined heat and power generator (CHP). 5.4 Lessons learnt from experience. 5.5 Economy. 5.6 CHP manufacturers. 6 Biogas for feeding into the natural gas network. 6.1 Biogas for feeding into the natural gas network in 6.2 Biogas for feeding into the natural gas network in Sweden. 6.3 Biogas for feeding into the natural gas network in Germany. 7 Biogas as fuel for vehicles. 7.1 Example project: chain of restaurants in Switzerland. 7.2 Example projects in Sweden. Part VII Residues and waste water. 1 Residues. 2 Waste water. Attachment I Typical design calculation for an agricultural biogas plant. Attachment II Economy of biogas plants for the year 2007 (Calculation on the basis of the example of Attachment I). Literature. Index.

Kinetic investigations of methane co-fermentation of sewage sludge and organic fraction of municipal solid wastes

In the presented study the co-fermentation, fermentation of sewage sludge (SS) and fermentation of organic fraction of municipal solid waste (OFMSW) were compared. The goal of experiments was determination of the processes carbon balance and proposal of the simple kinetic model of anaerobic digestion. Three batch experiments with above mentioned feedstocks were conducted in large scale laboratory reactor of working volume of 40 dm 3. The cumulative biogas production for sewage sludge (180.59 dm 3) was lower than that for co-fermentation (232 dm 3) or OFMSW (228.34 dm 3). During fermentation of the OFMSW an accumulation of volatile fatty acids (VFA) caused pH decrease and strongly inhibited gas production. The addition of co-substrate improved buffering capacity of fermentation broth. The suggested mathematical descriptions of carbon division in anaerobic digestion processes gave the satisfying conformity with the experimental values.

Technology for biohydrogen production through anaerobic sewage sludge fermentation

Technology for biohydrogen production through anaerobic sewage sludge fermentation

Determination of toluene formed during fermentation of sewage sludge

The results of determination of toluene in samples of sewage sludge by purge and trap technique are presented. The research on the fermentation process allowed the observation of the phenomenon of toluene formation. The increase in concentration of this compound ranged from about 3 mg/L to more than 24 mg/L for samples taken from WWTP ‘Gdansk Wschod’ and from 0.6 mg/L to above 4.5 mg/L for samples taken from WWTP ‘Debogorze’. An increase in toluene concentration to a certain maximum value was observed during the first stage of this process; it was then followed by a concentration decrease.

Investigation into antimony mobility in sewage sludge fermentation

Antimony is distributed in the environment in inorganic and organic species with different solubility and mobility characters. Here we investigate the transformation of antimony in view of biomethylation during sewage sludge fermentation as a case study for an anaerobic environment. Our approach was to identify if antimony methylation follows the Challenger pathway by using isotopically enriched antimonite (123Sb(v)). The antimony source was subjected to methylation in sewage sludge, an anaerobic dominant methanogenic Archaea community. The antimony species were determined in the gas phase using cryotrapping (CT)-GC-ICP-MS, and in the medium (sewage slude) by hydride generation (HG) prior CT-GC-ICP-MS. The determined 123/121Sb isotope ratios in the volatile trimethylstibine and non-volatile methylantimony species indicated that the methylation follows the proposed methylation pathway. With this approach we were able to quantify 123Sb incorporation into monomethyl-, dimethyl- and trimethylantimony, respectively. The incorporation decreased with further methylation from 91% to 82% and 73%. Volatilisation as trimethystibine was generally lower than 0.1%, however, up to 0.8% of added antimony was found methylated to methylantimony species and mainly accumulated in the cell. Moreover, antimony biomethylation was enhanced by stimulation of the anaerobic communities of methanogenic Archaea and sulfate reducing bacteria (SRB), with the methanogens showing a higher activity.

Feasibility study for co-digestion of sewage sludge with OFMSW on two wastewater treatment plants in Germany

In the past years, wastewater treatment plants (WWTP) in Germany have often been enlarged or expanded. However, it has become evident that the prognosticated increase in wastewater amount has not become a reality and thus free capacities, particularly in the sewage sludge digesters, are available. A possibility for the use of these available capacities is the fermentation of sewage sludge together with organic waste. A feasibility study for two different wastewater treatment plants in Germany was done in order to estimate if fermentation of the organic fraction of municipal solid waste (OFMSW) affects the wastewater treatment plant operation. In this study, the technical, economic and ecological aspects of co-digestion were investigated for the plants selected.

Anaerobic co-digestion of sewage sludge and organic fraction of municipal solid wastes

The paper presents the results of investigation of methane fermentation of sewage sludge and organic fraction of municipal solid wastes (OFMSW) as well as the cofermentation of both substrates under thermophilic and mesophilic conditions. In the first experiment the primary sludge and thickened excess activated sludge were fed into a 40 dm 3 bioreactor operated thermophilically. The second co-fermentation experiment was conducted with the mixture of sewage sludge (75%) and OFMSW (25%) in the same bioreactor arrangement. The other three experiments (III and IV, V) were carried out in quasi-continuous mode in two separated stages: acidogenic digestion in the continuous stirred tank bioreactor under thermophilic conditions (56 °C) and mesopholic methane fermentation (36 °C). The third experiment was conducted with the substrate-OFMSW only, in the fourth run sewage sludge from a municipal water treatment plant was used. In the fifth experiment a mixture of sewage sludge and OFMSW was used. In all experiments the following data were determined: biogas content and productivity, pH, total suspended and volatile solids, elemental content (C, H, N, S) of sludge, OFMSW and inoculum, total organic carbon, total alkalinity and volatile fatty acid content. Comparing the elemental analysis of sewage sludge and OFMSW it is evident that N content is higher in the sludge than in the OFMSW, however, the carbon content relation is the opposite, which may be beneficial to methane yield of co-digestion. Methane concentration in the biogas was above 60% in all cases. Biogas productivity varied between 0.4 and 0.6 dm 3/g VSS add depending on substrate added to the digester. The obtained results are generally consistent with literature data.

00/02453 Methanogenesis of carbohydrates and their fermentation products by syntrophic methane producing bacteria isolated from freshwater sediments

This study aims to study the methane generation potential (BMP tests) of different samples from the dark acid fermentation of sewage sludge:wine vinasse, and sewage sludge:wine vinasse:poultry manure. Specifically, mixtures of sewage sludge (S) and wine vinasse (V) were used in a 50:50 ratio and mixtures of sewage sludge and wine vinasse with 10 g/L of poultry manure (PM) (50:50 + 10 g/L) (S:V + PM). The goal was to determine the effect of the high ammonia concentrations in poultry manure when was used as co-substrate in the anaerobic methanogenic degradation of sewage sludge and vinasse. Results obtained show that the addition of 10 g/L of poultry manure to the SV mixture improves the production of methane generation, reaching values of 166 mL of accumulated methane. The SVPM mixture shows the highest purification percentages, with 63.90% TCOD removal, 79.51% SCOD removal and a yield of 52.05 mLCH4/gSVadded. The SVPM test showed a higher concentration of microorganisms during the BMP test, although the population of microorganisms for the SV test was doubled and presented greater activity with values of 2.27 versus 1.73E-11 LCH4/Cells.

Speciation of volatile mercury species present in digester and deposit gases

Volatile mercury compounds have been speciated in gases evolved from fermentation of sewage sludge as well as municipal waste. The species were trapped by sequential sampling, using a noble-metal trap in series with an activated-carbon trap. Thermally desorbed Hg0 and (CH3)2Hg were separated by GC at 70 °C and detected by cold vapour atomic fluorescence spectroscopy after thermal reduction. The amounts of mercury detected in the sewage gas correspond to concentrations in the range 50–110 ng m−3 for both species whereas the deposit gases were found to contain only elemental mercury. Monomethylmercury species could not be positively identified in any of the gas samples. Copyright © 1999 John Wiley & Sons, Ltd.

Complementary use of capillary gas chromatography–mass spectrometry (ion trap) and gas chromatography–inductively coupled plasma mass spectrometry for the speciation of volatile antimony, tin and bismuth compounds in landfill and fermentation gases†

ICP-MS is very sensitive and has limited matrix effects when used as an element-specific detector for GC in order to identify volatile metal or metalloid species. GC–MS is not very sensitive or selective in the electron ionization (EI) mode, but provides molecular information about volatile species. In this work, an ion trap EI-MS–MS and an ICP-MS system were used as two different detectors for the same GC system to provide complementary information about volatile organometallic species in the complex matrices of landfill and sewage sludge fermentation gases. A simple robust GC separation method with cryotrapping was adequate for the separation of the different metal(loid) containing volatile compounds, and was directly coupled to the ICP-MS system. In addition, gas samples from this GC system were collected in evacuated vials. These fractions were further separated on a capillary column and detected in an ion trap mass spectrometer. For the first time, parent ions, fragmentation patterns, isotopic ratios for Sb and Sn, and MS–MS data were used to identify positively Me3Sb, Me4Sn and Et2Me2Sn in landfill gas and Me3Sb and Me3Bi in fermentation gas.

Effect of the substrate-concentration on the methane fermentation of sewage sludge

In batch fermentation tests the effect of the substrate concentration on the methane fermentation process of the sewage sludge was controlled. In the range of 1.5 up to 6.5 percent of dry solids content in the raw sludge no changes could be demonstrated in the fermentation course, digestion of the organic substance, sludge gas production and in the organic compounds decomposition. The ratio of the solid phase concentration to the water content determined the ion concentration of the solution, which during the fermentation process would increase. The ion concentration affects the enzymatic activity of the bacteria and their metabolic process as well. The increase of the concentration of some ions, e.g. of ammonia-ions, above the given limit would inhibit the fermentation course. At conditions of the tests this limit would not be exceeded so that the inhibition of the fermentation could not be observed. In accordance with the composition of the mineral and organic part of the sludge particles the buffer capacity of media would result which is considered to be most significant for preserving the pH value in suitable limits for the bacteria, participating on the methane fermentation of organic substrate.