Enhancement of biogas production efficiency using appropriate low‐temperature pretreatments of municipal treatment plants' excess sludge

2018 ◽  
Vol 38 (3) ◽  
pp. e13072
Author(s):  
Mehdi Rafiee ◽  
Elaheh Salehi ◽  
Khashayar Sharifi ◽  
Amir H. Mohammadi ◽  
Aliasghar Rohani ◽  
...  
Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3434
Author(s):  
Iwona Zawieja ◽  
Małgorzata Worwąg

Human functioning related to living and economic activity involves generating an increasing amount of sewage and sludge, which needs to be subjected to advanced processes of treatment, neutralization, and management. The deterioration in the susceptibility of excess sludge to biochemical decomposition observed under anaerobic conditions leads to the development and application of highly effective methods of wastewater treatment based on the removal of biogenic compounds using activated sludge, with a high degree of sludge thickening obtained in mechanical facilities. The concentration of volatile fatty acids, being an important intermediate product of anaerobic stabilization, directly determines biogas production efficiency. This study aimed to determine the effect of chemical disintegration with peracetic acid on biogas production efficiency using methane fermentation of pretreated sludge. Intensification of the hydrolysis phase is an important determinant of the efficiency of biochemical sludge decomposition under anaerobic conditions. The association of excess sludge oxidation, initiated by peracetic acid with biological hydrolysis, which is the first phase of methane fermentation, led to an increase in sludge digestion degree and biogas production efficiency. The compound of STERIDIAL W-10, which is an aqueous solution of 10% peracetic acid, 10% acetic acid, and 8% hydrogen peroxide, was used. The disintegration of excess sludge with a reactant dose of 3.0 mL of STERIDIAL W-10/L yielded a specific biogas production of 0.52 L/g VSS and a 74% degree of sludge digestion.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karol Postawa ◽  
Jerzy Szczygieł ◽  
Marek Kułażyński

Abstract Background Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration.


2015 ◽  
Vol 10 (1) ◽  
pp. 133-142 ◽  
Author(s):  
H.-B. Ding ◽  
M. Doyle ◽  
A. Erdogan ◽  
R. Wikramanayake ◽  
P. Gallagher

This paper presents two types of dissolved air flotation application together with biosorption (the ‘Captivator® system’) as primary treatments. In the first instance, the Captivator® system is the sole primary treatment for a new plant installation and helps to gain 65% more biogas while requiring only 44% of aeration for COD oxidation, compared to a conventional process with a primary clarifier. In the second application, the Captivator® system is used to enhance the existing primary treatment for plant capacity expansion. With digested anaerobic sludge recycled as an additional adsorbent, the Captivator® system in the second application increases the biogas yield by 52% and only generates 59% excess sludge. Overall, the Captivator® system would help WWTPs to approach energy neutrality by diverting more organics for biogas production and reducing the energy requirements for aeration. In addition, it would help to reduce the installation footprint for primary treatment and save considerable capital cost by eliminating the sludge thickening process.


2021 ◽  
Vol 15 (3) ◽  
pp. 302-311
Author(s):  
Jingping Dai ◽  
Jiang Li ◽  
Wang Zhifang ◽  
Xie Yuqing ◽  
Wang Xiaou ◽  
...  

To fill the gap between the rise in demand for energy and decline in the traditional energy sources such as coal, natural gas and nuclear energy, other alternative sources such as biogas are necessary. Studies have shown that the existing conditions within the fermentation realm control the microbial characteristics in biogas production. However, there is inadequate insight between the duration of fermentation and the microbial diversity, and with specific emphasis to cow manure as the substrate under low temperature fermentation. This study aimed at providing additional insight on the effect of varying fermentation duration (0 to 60 days) on the composition of the dominant microbial flora on cow dung based low-temperature (15 °C) biogas fermentation using metagenomics and metabolomics analyses approach. The study results showed that the main dominant community in the process of methanogenesis are the Spirochaetae, Synergistetes and Chloroflexi, and are new flora in the methane phase. In the peak stage of low-temperature biogas fermentation, the dominant bacteria groups were Methanosarcina and after adding 10% concentration of L1 bacteria. The prediction of metabolic pathway was mainly carbohydrate metabolism and amino acid metabolism with succinyl-CoA synthase a subunit, lactaldehyde reductase and the glutamate-glyoxylate aminotransferase being the main unique enzymes. The study therefore supports the potential of involving the reported dominant microbial communities and related enzymatic activities for improved biogas production under low temperature conditions.


2019 ◽  
Vol 116 ◽  
pp. 00104
Author(s):  
Iwona Zawieja ◽  
Kinga Brzeska

The advanced oxidation processes (AOPs) play an important role in the degradation of hardly decomposable organic pollutants. AOPs methods rely on the production of highly reactive hydroxyl OH• radicals. The aim of the conducted research was to intensify biogas production in the methane fermentation process of excess sludge subjected to the process of deep oxidation with Fenton's reagent. In the process of oxidation of sewage sludge with the Fenton reagent, doses of iron ions in the range 0.02–0.14 g Fe2+/g TS (total solids) were used Hydrogen peroxide was measured in the proportions 1: 1–1:10 in relation to the mass of iron ions. The basic substrate of the study was excess sludge. In the case of excess sludge oxidation with the use of Fenton's reagent, the most favorable process conditions were considered to be the dose of iron ions 0.08 g Fe2+/g d.m. and a Fe2+: H2O2 ratio of 1:5. As a result of subjecting the excess sludge to disintegration with the Fenton reagent in the above-mentioned dose, with respect to the fermentation process of unprocessed sludge, about two-fold increase in the digestion degree of excess sludge and about 35% increase of the biogas yield was obtained.


2019 ◽  
Vol 28 ◽  
pp. 140-152 ◽  
Author(s):  
Farid Haghighat Shoar ◽  
Reza Abdi ◽  
Bahman Najafi ◽  
Sina Faizollahzadeh Ardabili

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 133 ◽  
Author(s):  
Shiwei Wang ◽  
Fang Ma ◽  
Weiwei Ma ◽  
Ping Wang ◽  
Guang Zhao ◽  
...  

In this study, the influence of temperature on biogas production efficiency and the microbial community structure was investigated in a two-phase anaerobic digestion reactor for co-digestion of cow manure and corn straw. The results illustrated that the contents of solluted chemical oxygen demand (SCOD) and volatile fatty acid (VFA) in the acidogenic phase and biogas production in the methanogenic phase maintained relatively higher levels at temperatures ranging from 35–25 °C. The methane content of biogas production could be maintained higher than 50% at temperatures above 25 °C. The microbial community structure analysis indicated that the dominant functional bacteria were Acinetobacter, Acetitomaculum, and Bacillus in the acidogenic phase and Cenarchaeum in the methanogenic phase at 35–25 °C. However, the performances of the acidogenic phase and the methanogenic phase could be significantly decreased at a lower temperature of 20 °C, and microbial activity was inhibited obviously. Accordingly, a low temperature was adverse for the performance of the acidogenic and methanogenic phases, while moderate temperatures above 25 °C were more conducive to high biogas production efficiency.


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