Integrated chemical, physical and biological processes modelling of anaerobic digestion of sewage sludge

2006 ◽  
Vol 54 (5) ◽  
pp. 109-117 ◽  
Author(s):  
S.W. Sötemann ◽  
P. van Rensburg ◽  
N.E. Ristow ◽  
M.C. Wentzel ◽  
R.E. Loewenthal ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Short Chain Fatty Acids ◽  
Weak Acid ◽  
Mass Balances ◽  
Two Phase ◽  
Anaerobic Digesters ◽  
Hydrolysis Process ◽  
Water Association

The biological kinetic processes for anaerobic digestion (AD) are integrated into a two phase subset of a three phase mixed weak acid/base chemistry kinetic model. The approach of characterising sewage sludge into carbohydrates, lipids and proteins, as is done in the International Water Association (IWA) AD model No 1 (ADM1), requires measurements that are not routinely available on sewage sludges. Instead, the sewage sludge is characterised with the COD, carbon, hydrogen, oxygen and nitrogen (CHON) composition and is formulated in mole units, based on conservation of C, N, O, H and COD. The model is calibrated and validated with data from laboratory mesophilic anaerobic digesters operating from 7 to 20 d sludge age and fed a sewage primary and humus sludge mixture. These digesters yielded COD mass balances between 107–109% and N mass balances between 91–99%, and hence the experimental data is accepted as reasonable. The sewage sludge COD is found to be 32–36% unbiodegradable (depending on the kinetic formulation selected for the hydrolysis process) and to have a C3.5H7O2N0.196 composition. For the selected hydrolysis kinetics of surface mediated reaction (Contois), with a single set of kinetic and stoichiometric constants, for all retention times good correlation is obtained between predicted and measured results for: (i) COD; (ii) free and saline ammonia (FSA); (iii) short chain fatty acids (SCFA); (iv) H2CO3* alkalinity; (v) pH of the effluent stream; (vi) CO2; and (vii) CH4 gases in the gas stream. The measured composition of primary sludge from two local wastewater treatment plants ranged between C3.38H7O1.91N0.21 and C3.91H7O2.04N0.16. The predicted composition based on mass balances is therefore within 5% of the average measured composition providing persuasive validation of the model.

Sludge minimization by disintegration at different wastewater treatment plants

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Luchien Luning ◽  
Paul Roeleveld ◽  
Victor W.M. Claessen
Keyword(s):  
Organic Matter ◽  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
New Technologies ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Biological Degradation ◽  
Ongoing Research ◽  
Sludge Minimization

In recent years new technologies have been developed to improve the biological degradation of sewage sludge by anaerobic digestion. The paper describes the results of a demonstration of ultrasonic disintegration on the Dutch Wastewater Treatment Plant (WWTP) Land van Cuijk. The effect on the degradation of organic matter is presented, together with the effect on the dewatering characteristics. Recommendations are presented for establishing research conditions in which the effect of sludge disintegration can be determined in a more direct way that is less sensitive to changing conditions in the operation of the WWTP. These recommendations have been implemented in the ongoing research in the Netherlands supported by the National Institute for wastewater research (STOWA).

The Ruhrverband sewage sludge disposal concept in the conflict between European and German standards and regulations

2005 ◽  
Vol 52 (10-11) ◽  
pp. 247-253
Author(s):  
P. Evers ◽  
F. Schmitt ◽  
D.R. Albrecht ◽  
N. Jardin
Keyword(s):  
Sewage Sludge ◽  
River Basin ◽  
Agricultural Land ◽  
Wastewater Treatment Plants ◽  
Integrated Water Resources Management ◽  
Toxic Substances ◽  
Sludge Incineration ◽  
Sludge Disposal ◽  
The Face ◽  
Water Association

The Ruhrverband, acting as a water association responsible for integrated water resources management within the entire natural river basin of the Ruhr, operates a network of 83 wastewater treatment plants (WWTPs) and connected sludge disposal facilities. According to German regulations, the disposal of sewage sludge containing more than 5% of organic dry solids will be prohibited as of 1 June 2005. In Germany, the only future alternative to incineration will be the agricultural utilization of sludge. However, this way of sludge disposal is presently the subject of critical discussions in Germany because of the organic and inorganic toxic substances, which may be contained in sewage sludge, despite the fact that very stringent standards are to be met by agricultural uses. On the other hand, application of sewage sludge to agricultural land is explicitly supported by the European Sewage Sludge Directive 86/278/EEC. In the face of this controversial situation the Ruhrverband has initiated, in 2000, the development of a comprehensive and sustainable sludge and waste disposal concept for all wastewater facilities it operates in the entire Ruhr River Basin. The concept includes de-central sludge digestion and dewatering and subsequent transport to two central sludge incineration plants. It is expected that in future not more than 5% of all sludges produced in Ruhrverband's WWTPs will be used in agriculture. That means, the major part of 95% will have to be incinerated.

Minimisation of excess sludge production in a WWTP by coupling thermal hydrolysis and rapid anaerobic digestion

2005 ◽  
Vol 52 (10-11) ◽  
pp. 255-263 ◽  
Author(s):  
J. Chauzy ◽  
S. Graja ◽  
F. Gerardin ◽  
D. Crétenot ◽  
L. Patria ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Pilot Plant ◽  
Hydraulic Retention Time ◽  
Wastewater Treatment Plants ◽  
Control Line ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
Anaerobic Digesters ◽  
Sludge Production

In many cases, reducing sludge production could be the solution for wastewater treatment plants (WWTP) that here difficulty evacuating the residuals of wastewater treatment. The aim of this study was to test the possibility of minimising the excess sludge production by coupling a thermal hydrolysis stage and an anaerobic digestion with a very short HRT. The tests were carried out on a 2,500 p.e. pilot plant installed on a recycling loop between the clarifier and the actived sludge basin. The line equipped with the full scale pilot plant produced 38% TSS less than the control line during a 10 week period. Moreover, the rapid anaerobic digestion removed, on average, more than 50% of the total COD load with a hydraulic retention time (HRT) of 3 days. Lastly, the dryness of the remaining excess sludge, sanitised by the thermal hydrolysis, was more than 35% with an industrial centrifuge. This combination of thermal hydrolysis and rapid anaerobic digestion equally permits a significant gain of compactness compared to traditional anaerobic digesters.

Effect of anaerobic digestion and liming on plant availability of phosphorus in iron- and aluminium-precipitated sewage sludge from primary wastewater treatment plants

2017 ◽  
Vol 75 (7) ◽  
pp. 1743-1752 ◽  
Author(s):  
Emilio Alvarenga ◽  
Anne Falk Øgaard ◽  
Lasse Vråle
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Negative Impact ◽  
Limited Resource ◽  
Primary Treatment ◽  
P Uptake ◽  
Lime Treatment ◽  
Plant P Uptake ◽  
P Removal

More efficient plant utilisation of the phosphorus (P) in sewage sludge is required because rock phosphate is a limited resource. To meet environmental legislation thresholds for P removal from wastewater (WW), primary treatment with iron (Fe) or aluminium (Al) coagulants is effective. There is also a growing trend for WW treatment plants (WWTPs) to be coupled to a biogas process, in order to co-generate energy. The sludge produced, when stabilised, is used as a soil amendment in many countries. This study examined the effects of anaerobic digestion (AD), with or without liming as a post-treatment, on P release from Fe- and Al-precipitated sludges originating from primary WWTPs. Plant uptake of P from Fe- and Al-precipitated sludge after lime treatment but without AD was also compared. Chemical characterisation with sequential extraction of P and a greenhouse experiment with barley (Hordeum vulgare) were performed to assess the treatment effects on plant-available P. Liming increased the P-labile fraction in all cases. Plant P uptake increased from 18.5 mg pot−1 to 53 mg P pot−1 with liming of Fe-precipitated sludge and to 35 mg P pot−1 with liming of the digestate, while it increased from 18.7 mg pot−1 to 39 and 29 mg P pot−1 for the Al-precipitated substrate and digestate, respectively. Thus, liming of untreated Fe-precipitated sludge and its digestate resulted in higher P uptake than liming its Al-precipitated counterparts. AD had a negative impact on P mobility for both sludges.

Two-Phase Mesophilic Anaerobic Co-Digestion of Food Waste and Sewage Sludge: Effect of Hydraulic Retention Time

2014 ◽  
Vol 852 ◽  
pp. 789-796 ◽  
Author(s):  
Guo Hua Wang ◽  
Lei Wang ◽  
Xue Jun Tan ◽  
Yi Xian Wang ◽  
Feng Wang
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Food Waste ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Removal Rate ◽  
Two Phase ◽  
Acidogenic Reactor ◽  
In Series ◽  
The Impact

The impact of hydraulic retention time (HRT) on two-phase mesophilic (35°C) anaerobic co-digestion of food waste and sewage sludge was studied under mixing ratio of 1:1 on the TS basis. Laboratory-scale, two-phase anaerobic digestion systems were employed with each system consisting of an acidogenic reactor and a methanogenic reactor linked in series. For the acidogenic phase, an increase of volatile fatty acid (VFA) concentration was observed as HRT increased from 1d to 5d and the HRT of 5d was recommended for significantly higher VFA production and less propionate percentage, which could provide stable and favourable substrates for the methane reactor. Under acidogenic HRT of 5d, 20d was proved to be the optimum HRT for methanogenic phase with the methane content, methane production rate, methane yield and two-phase VS removal rate reached 71%, 0.7L/(L·d), 0.69L/gVSremoved and 64.7%, respectively. Results verified that the constraints of conventional anaerobic digestion for food waste or sewage sludge separately could be overcome by synergistic effect of co-digestion strategy and two-phase treatment.

scholarly journals The Energetic Aspect of Organic Wastes Addition on Sewage Sludge Anaerobic Digestion: A Laboratory Investigation

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6113
Author(s):  
Aleksandra Szaja ◽  
Agnieszka Montusiewicz ◽  
Magdalena Lebiocka
Keyword(s):  
Anaerobic Digestion ◽  
Energy Balance ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Organic Wastes ◽  
Successful Implementation ◽  
Anaerobic Reactors ◽  
Component Systems ◽  
Key Factor ◽  
Energetic Aspect

One of the possibilities to achieve energy neutrality of wastewater treatment plants (WWTPs) is the implementation of the anaerobic co-digestion strategy. However, a key factor in its successful implementation on the technical scale is the application of components with complementary composition to sewage sludge (SS). In the 7resent study, the influence of adding various co-substrates on the energy balance of anaerobic digestion was evaluated. The following organic wastes were used as additional components to SS: organic fraction of municipal solid waste (OFMSW) and distillery spent wash (DW) applied in two- and three-component systems. The experiments were performed in semi-flow anaerobic reactors with the volume of 40 L under mesophilic conditions (35 °C) at hydraulic retention time (HRT) of 20, 18, and 16 d. The application of substrates to SS resulted in enhancements of methane yields as compared to SS mono-digestion. The statistically significant differences were observed in tertiary mixtures at both HRT of 18 and 16 d. Therein, average values were 0.20 and 0.23 m3 kg−1VSadd at HRT of 18 and 16 d, respectively. Among all co-digestion series, the most beneficial effect on energy balance was found in 20% v/v DW presence in both two- and three-component systems at HRT of 16 d.

scholarly journals Insights on anaerobic digestion foaming via association between bacterial metabolism and variations in microbiota

2020 ◽  
Author(s):  
Jian-Lu Duan ◽  
Yue Feng ◽  
Li-Juan Feng ◽  
Jing-Ya Ma ◽  
Xiao-Dong Sun ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Short Chain Fatty Acids ◽  
Process Efficiency ◽  
Metabolic Phenotype ◽  
Bacterial Metabolism ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Anaerobic Digesters ◽  
Global Concern

Abstract Background: Foaming in anaerobic digesters is considered a global concern due to significant impacts on process efficiency and operational costs. Although the importance of the organic loading rate on anaerobic foaming is now widely recognized, little is known about the key bacteria among the hundreds of species inducing foaming, especially the metabolite-microbiota correlation that influences foaming in anaerobic digesters.Results: Here, we show that the organic loading rate promotes foaming and decreases the performances of bench-scale batch digesters. Metabolomics analysis revealed distinct changes in the metabolic phenotype, including mainly short-chain fatty acids and amino acids, decreasing the surface tension and inducing foaming. Furthermore, the correlation analysis revealed that Clostridium clusters were the main microbes contributing to these metabolite foaming incidents.Conclusions: We provide the foaming microbes and metabolites in anaerobic digestion. Our findings elucidate the complex formation of foaming in anaerobic digestion and provide an effective early-warning for the control of foaming in full-scale digesters.

scholarly journals Identifying the abundant and active microorganisms common to full-scale anaerobic digesters

2017 ◽  
Author(s):  
Rasmus H. Kirkegaard ◽  
Simon J. McIlroy ◽  
Jannie M. Kristensen ◽  
Marta Nierychlo ◽  
Søren M. Karst ◽  
...  
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Microbial Community Composition ◽  
Amplicon Sequencing ◽  
Full Scale ◽  
Rrna Gene ◽  
Anaerobic Digesters ◽  
Abundant Otus ◽  
Source Of Information

AbstractAnaerobic digestion is widely applied to treat organic waste at wastewater treatment plants. Characterisation of the underlying microbiology represents a source of information to develop strategies for improved operation. To this end, we investigated the microbial community composition of thirty-two full-scale digesters over a six-year period using 16S rRNA gene amplicon sequencing. Sampling of the sludge fed into these systems revealed that several of the most abundant populations were likely inactive and immigrating with the influent. This observation indicates that a failure to consider immigration will interfere with correlation analysis and give an inaccurate picture of the active microbial community. Furthermore, several abundant OTUs could not be classified to genus level with commonly applied taxonomies, making inference of their function unreliable. As such, the existing MiDAS taxonomy was updated to include these abundant phylotypes. The communities of individual plants surveyed were remarkably similar – with only 300 OTUs representing 80% of the total reads across all plants, and 15% of these identified as likely inactive immigrating microbes. By identifying the abundant and active taxa in anaerobic digestion, this study paves the way for targeted characterisation of the process important organisms towards an in-depth understanding of the microbial ecology of these biotechnologically important systems.

scholarly journals Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge

2016 ◽  
Vol 74 (3) ◽  
pp. 595-605 ◽  
Author(s):  
S. Rodriguez-Perez ◽  
F. G. Fermoso ◽  
C. Arnaiz
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Biomass Production ◽  
Reduction Method ◽  
Wastewater Treatment Plants ◽  
Biomass Concentration ◽  
Sludge Reduction ◽  
Filamentous Bacteria ◽  
Active Biomass

Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

Sewage Sludge Thermal Hydrolysis Process

2013 ◽  
Vol 827 ◽  
pp. 368-373
Author(s):  
Guang Li ◽  
He Ren ◽  
Jing Li ◽  
Xiang Kui Han ◽  
Lian Peng Wang
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Organic Acids ◽  
Temperature Rise ◽  
Suspended Solids ◽  
Concentration Change ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
Hydrolysis Process ◽  
Hydrolysis Temperature

In 110~190°C for 15~75min excess sludge thermal hydrolysis test, investigated the dissolution rate of the volatile suspended solids, Sludge SCOD, TCOD concentration change in composition of organic acids in the supernatant, and analysis the improvement of the anaerobic digestion performance. The results show that, with the increase of thermal hydrolysis temperature and extension of time, sludge supernatant on SCOD, VFA rising. At 190 °C, 75min conditions, SCOD, VFA reached the maximum 6674mg / L2630mg/ L; Sludge organic solids dissolved and the release of COD, etc. mainly in the first 45 min to complete, little change after 45min. When thermal hydrolysis temperature between 90~170°C, anaerobic digestion performance increase with temperature rise, When the temperature is higher than 170 °C, the sludge anaerobic digestion performance begins to decline.

Sign in / Sign up

Export Citation Format

Share Document