scholarly journals Influence of conditioning agents and enzymic hydrolysis on the biochemical methane potential of sewage sludge

2013 ◽  
Vol 68 (7) ◽  
pp. 1622-1632 ◽  
Author(s):  
Elena Marañón ◽  
Luis Negral ◽  
Yolanda Fernández-Nava ◽  
Leonor Castrillón
Keyword(s):  
Sewage Sludge ◽  
Methane Production ◽  
Wastewater Treatment Plants ◽  
Solid Phase ◽  
Enzymic Hydrolysis ◽  
Biochemical Methane Potential ◽  
General Improvement ◽  
Methane Potential ◽  
Pre Treatment ◽  
Cationic Polyelectrolytes

Biochemical methane potential (BMP) tests have been carried out on sewage sludge from two wastewater treatment plants to assess the effect of additives (FeCl3 and two cationic polyelectrolytes) used in sludge dewatering. BMP tests were also carried out on the concentrated solid phase from the enzymic hydrolysis pre-treatment (42 °C, 48 h). FeCl3 had no significant effect on specific methane production, obtaining 242–246 LCH4/kgVSo. The effect of the combination of polyelectrolyte and FeCl3 depended on the polyelectrolyte and the sludge, but generally led to an increase in specific methane production (25–40%). When enzymic hydrolysis was applied as a pre-treatment, specific methane production increased from 6.8% in the sludge containing FeCl3 to 20% in the sludge without FeCl3, although the increases were not statistically significant. In terms of LCH4/kgVSrem, a general improvement was achieved both by means of additives and by enzymic hydrolysis. However, this improvement was only significant in the case of sludge which had undergone previous enzymic hydrolysis (62%) and in the untreated sludge containing a polyelectrolyte and FeCl3 (24%). Cationic polyelectrolytes inhibited solid–liquid separation during enzymic hydrolysis and, although the presence of only FeCl3 did not affect this separation, a significant decrease (32%) in LCH4/kgVSrem was observed.

Solid thickening and methane production of livestock wastewater using dissolved carbon dioxide flotation

2015 ◽  
Vol 51 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Dong-Heui Kwak ◽  
Soo-Wan Chae
Keyword(s):  
Wastewater Treatment ◽  
Methane Production ◽  
Wastewater Treatment Plants ◽  
Biochemical Methane Potential ◽  
Livestock Wastewater ◽  
Co2 Gas ◽  
Dissolved Carbon ◽  
Dissolved Carbon Dioxide ◽  
Methane Potential ◽  
Sludge Thickening

Dilute manure is classified as wastewater due to the large quantity of water used in livestock production in Korea. Livestock wastewater treatment is required in order to reduce high moisture content and treat fluids discharged from the digestion process. In livestock wastewater treatment plants, large quantities of CO2 gas are produced at combined heat and power facilities as well as in the anaerobic digestion (AD) process. This gas produced during livestock wastewater treatment can be used as a separator of solids from liquid in wastewater. In this study, a flotation system using recycled CO2 gas was used for sludge thickening. An anaerobic toxicity assay (ATA) and a biochemical methane potential assay were used to assess the toxicity impact of recycling CO2 on the methane production potential. ATA experiments confirmed that CO2 toxicity did not impair the AD process. The tests indicated that the cumulative methane yield from influent livestock manure enriched with CO2 was approximately 190 mL-CH4/g-VSadded. The data demonstrated the potential of using dissolved CO2 flotation in the AD of diluted livestock wastewater.

Optimization of municipal sludge and grease co-digestion using disintegration technologies

2012 ◽  
Vol 65 (2) ◽  
pp. 214-220 ◽  
Author(s):  
L. Bouchy ◽  
A. Pérez ◽  
P. Camacho ◽  
P. Rubio ◽  
G. Silvestre ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Enzymatic Treatment ◽  
Hydrodynamic Characteristics ◽  
Thermal Hydrolysis ◽  
Municipal Sludge ◽  
Secondary Sludge ◽  
Methane Potential ◽  
Pre Treatment ◽  
Maximum Increment

Many drivers tend to foster the development of renewable energy production in wastewater treatment plants as many expectations rely upon energy recovery from sewage sludge, for example through biogas use. This paper is focused on the assessment of grease waste (GW) as an adequate substrate for co-digestion with municipal sludge, as it has a methane potential of 479–710 LCH4/kg VS, as well as the evaluation of disintegration technologies as a method to optimize the co-digestion process. With this objective three different pre-treatments have been selected for evaluation: thermal hydrolysis, ultrasound and enzymatic treatment. Results have shown that co-digestion processes without pre-treatment had a maximum increment of 128% of the volumetric methane productivity when GW addition was 23% inlet (at 20 days of HRT and with an OLR of 3.0 kg COD/m3d), compared with conventional digestion of sewage sludge alone. Concerning the application of the selected disintegration technologies, all pre-treatments showed improvements in terms of methane yield (51.8, 89.5 and 57.6% more for thermal hydrolysis, ultrasound and enzymatic treatment, respectively, compared with non-pretreated wastes), thermal hydrolysis of GW and secondary sludge being the best configuration as it improved the solubilization of the organic matter and the hydrodynamic characteristics of digestates.

scholarly journals Evaluation of Feasibility of Using the Bacteriophage T4 Lysozyme to Improve the Hydrolysis and Biochemical Methane Potential of Secondary Sludge

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3644
Author(s):  
Sangmin Kim ◽  
Seung-Gyun Woo ◽  
Joonyeob Lee ◽  
Dae-Hee Lee ◽  
Seokhwan Hwang
Keyword(s):  
Cell Wall ◽  
Bacterial Cell ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Bacteriophage T4 ◽  
Suspended Solid ◽  
T4 Lysozyme ◽  
Biochemical Methane Potential ◽  
Secondary Sludge ◽  
Methane Potential

Anaerobic digestion (AD) of secondary sludge is a rate-limiting step due to the bacterial cell wall. In this study, experiments were performed to characterize secondary sludges from three wastewater treatment plants (WWTPs), and to investigate the feasibility of using bacteriophage lysozymes to speed up AD by accelerating the degradation of bacterial cell walls. Protein was the main organic material (67.7% of volatile solids in the sludge). The bacteriophage T4 lysozyme (T4L) was tested for hydrolysis and biochemical methane potential. Variations in the volatile suspended solid (VSS) concentration and biogas production were monitored. The VSS reduction efficiencies by hydrolysis using T4L for 72 h increased and ranged from 17.8% to 26.4%. Biogas production using T4L treated sludges increased and biogas production was increased by as much as 82.4%. Biogas production rate also increased, and the average reaction rate coefficient of first-order kinetics was 0.56 ± 0.02/d, which was up to 47.5% higher compared to the untreated samples at the maximum. Alphaproteobacteria, Betaproteobacteria, Flavobacteriia, Gammaproteobacteria, and Sphingobacteriia were major microbial classes in all sludges. The interpretation of the microbial community structure indicated that T4L treatment is likely to increase the rate of cell wall digestion.

scholarly journals Innovative Hydrodynamic Disintegrator Adjusted to Agricultural Substrates Pre-treatment Aimed at Methane Production Intensification—CFD Modelling and Batch Tests

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4256 ◽  
Author(s):  
Monika Zubrowska-Sudol ◽  
Aleksandra Dzido ◽  
Agnieszka Garlicka ◽  
Piotr Krawczyk ◽  
Michał Stępień ◽  
...  
Keyword(s):  
Methane Production ◽  
Damage Zone ◽  
Positive Energy ◽  
Net Energy ◽  
Maize Silage ◽  
Cfd Modelling ◽  
Study Objective ◽  
Testing Procedures ◽  
Methane Potential ◽  
Pre Treatment

The study objective was to adjust the hydrodynamic disintegrator dedicated to sewage sludge pre-treatment (HDS) to work with agricultural substrate. This involved the development and implementation of a mathematical model of flow via the device’s domain. An innovative disintegrator (HAD—hydrodynamic disintegrator for agriculture) was designed, built, and tested based on the obtained results. The main improvements to the HDS include the implementation of shredding knives in order to overcome clogging by crushed substrate, and the application of ribs in the recirculation zone, contributing to the development of an additional structure damage zone. The challenge of this study was also to determine the operating parameters of the HDA that would provide for an increase in methane production with positive energy balance. The testing procedures, for which maize silage was selected, involved batch disintegration tests and biochemical methane potential tests. No clogging of rotor or spontaneous shutting off of the device, in other words, problems that had occurred in the HDS, were observed. The applied pre-treatment method permitted an increase in the methane potential of maize silage by 34.4%, 27.0%, and 21.6%, respectively for samples disintegrated at energy densities of 10 kJ/L, 20 kJ/L, and 35 kJ/L with net energy profit.

Assessing the role of biochemical methane potential tests in determining anaerobic degradability rate and extent

2011 ◽  
Vol 64 (4) ◽  
pp. 880-886 ◽  
Author(s):  
P. D. Jensen ◽  
H. Ge ◽  
D. J. Batstone
Keyword(s):  
Parameter Estimation ◽  
Methane Production ◽  
Estimation Method ◽  
Test Method ◽  
Continuous Systems ◽  
Batch Test ◽  
Biochemical Methane Potential ◽  
First Order ◽  
Methane Potential ◽  
The Impact

The biodegradability and bioavailability of hydrolysis-limited substrates under anaerobic (and aerobic) conditions can be represented by two key parameters – degradability (fd), or the percentage that can be effectively be destroyed during digestion, and first order hydrolysis coefficient (khyd), or the speed at which material breaks down. Biochemical methane potential (BMP) testing uses a batch test (in triplicate), and by fitting against a first order model, can fit both parameters in the same test. BMP testing is now being widely used for anaerobic process feasibility and design purposes, and standardisation efforts are ongoing. In this paper, we address a number of key issues relating to the test method and its analysis. This includes proposal of a new fitting and parameter estimation method, evaluation of the impact of inoculum to substrate ratio on fitted parameters, and comparison to performance in continuous systems. The new parameter estimation technique provides an estimate of parameter uncertainty and correlation, and is clearly more suitable than model transformation and linear regression. An inoculum volume ratio of at least 50% (2:1 on VS basis) was required on a cellulose substrate to use methane production as primary indicator, as found by comparing methane production and solubilisation of cellulose. Finally, on a typical material, waste activated sludge, the batch test was slightly conservative in terms of degradability and rate, indicating a bias in the BMP test. The test is a cost-effective and capable method to evaluate potential substrates, but it should be noted that it is generally conservative, especially if sub-optimal inoculum is used.

Biochemical methane potential from sewage sludge: Effect of an aerobic pretreatment and fly ash addition as source of trace elements

2017 ◽  
Vol 64 ◽  
pp. 140-148 ◽  
Author(s):  
César Huiliñir ◽  
Paula Pinto-Villegas ◽  
Alejandra Castillo ◽  
Silvio Montalvo ◽  
Lorna Guerrero
Keyword(s):  
Trace Elements ◽  
Fly Ash ◽  
Sewage Sludge ◽  
Biochemical Methane Potential ◽  
Methane Potential
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