Effect of moisture content on anaerobic digestion of dewatered sludge: ammonia inhibition to carbohydrate removal and methane production

2000 ◽  
Vol 41 (3) ◽  
pp. 119-127 ◽  
Author(s):  
S. Fujishima ◽  
T. Miyahara ◽  
T. Noike
Keyword(s):  
Anaerobic Digestion ◽  
Moisture Content ◽  
Removal Efficiency ◽  
Methane Production ◽  
Ammonia Concentration ◽  
Methanogenic Bacteria ◽  
Order Of Magnitude ◽  
Vs Removal ◽  
Effect Of Moisture ◽  
Dewatered Sewage Sludge

The purpose of this study is to investigate the effect of moisture content on anaerobic digestion of dewatered sewage sludge under mesophilic condition. The moisture contents of sludge fed to reactors were 97.0%, 94.6%, 92.9%, 91.1% and 89.0%. The VS removal efficiency changed from 45.6% to 33.8%, as the moisture content of sludge fed to digester decreased from 97.0% to 89.0%. The carbohydrate removal efficiency also decreased from 71.1% to 27.8%. Methane production decreased when the moisture content of sludge was lower than 91.1%. The number of glucose consuming acidogenic bacteria was decreased from 3.1×106 to 3.1×108(MPN/mL) as the moisture content decreased from 91.1% to 89.0%. The numbers of hydrogenotrophic and acetoclastic methanogenic bacteria decreased by one order of magnitude when the moisture content was lower than 91.1%. The decrease in numbers of glucose consuming acidogenic bacteria and methanogenic bacteria was found to correspond to the decrease in the carbohydrate removal efficiency and the accumulation of propionic acid. Batch experiments showed that acetoclastic methanogenic bacteria were acclimated to high ammonia concentration, on the other hand, glucose consuming acidogenic bacteria were inhibited.

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
J. A. Barrios ◽  
A. Cano ◽  
F. F. Rivera ◽  
M. E. Cisneros ◽  
U. Durán
Keyword(s):  
Anaerobic Digestion ◽  
Current Density ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Analysis ◽  
Mathematical Optimization ◽  
Waste Activated Sludge ◽  
Bdd Electrode ◽  
Vs Removal ◽  
Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

scholarly journals Performance Evaluation of Mesophilic Anaerobic Digestion of Chicken Manure with Algal Digestate

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1829 ◽  
Author(s):  
Na Duan ◽  
Xia Ran ◽  
Ruirui Li ◽  
Panagiotis Kougias ◽  
Yuanhui Zhang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Substrate Concentration ◽  
Tap Water ◽  
Total Solid ◽  
Ammonia Concentration ◽  
Chicken Manure ◽  
Resource Saving ◽  
Kinetics Parameters ◽  
Total Ammonia

Dilution is considered to be a fast and easily applicable pretreatment for anaerobic digestion (AD) of chicken manure (CM), however, dilution with fresh water is uneconomical because of the water consumption. The present investigation was targeted at evaluating the feasibility and process performance of AD of CM diluted with algal digestate water (AW) for methane production to replace tap water (TW). Moreover, the kinetics parameters and mass flow of the AD process were also comparatively analyzed. The highest methane production of diluted CM (104.39 mL/g volatile solid (VS)) was achieved with AW under a substrate concentration of 8% total solid (TS). The result was markedly higher in comparison with the group with TW (79.54–93.82 mL/gVS). Apart from the methane production, considering its energy and resource saving, nearly 20% of TW replaced by AW, it was promising substitution to use AW for TW to dilute CM. However, the process was susceptible to substrate concentration, inoculum, as well as total ammonia and free ammonia concentration.

scholarly journals Effect of Moisture on Gas Emissions from Stored Woody Biomass

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 128 ◽  
Author(s):  
Xiao He ◽  
Anthony K. Lau ◽  
Shahab Sokhansanj
Keyword(s):  
Moisture Content ◽  
Dry Matter ◽  
Dry Mass ◽  
Decay Resistance ◽  
Slight Reduction ◽  
Gas Emissions ◽  
Aerobic Conditions ◽  
Red Cedar ◽  
Order Of Magnitude ◽  
Effect Of Moisture

Biomass materials have been increasingly used due to their renewable nature. The problems occurring during the storage of fresh woody materials include gas emissions and dry matter losses as a result of degradation. The objective of this study was to investigate and quantify the effect of moisture content on gas emissions from stored wood chips. Experiments were conducted under non-aerobic and aerobic conditions using fresh Western Red Cedar (WRC) chips with different initial moisture contents over a range of temperatures. The peak CO2 emission factor of 2.9 g/kg dry matter (DM) was observed from high moisture chips at 20 °C under non-aerobic conditions after two-month storage, which was an order of magnitude greater than that from low moisture chips. In the case of volatile organic compounds, a range of compounds were detected from all tests. The concentration of VOCs was found to be positively correlated with moisture content. Gas emissions from the aerobic reactors exhibited similar trends as non-aerobic reactors with respect to the effect of moisture content, although higher values were observed under aerobic conditions. Slight reduction of dry mass from all tests at the end of storage indicated the decay-resistance characteristics of WRC.

scholarly journals Influence of moisture content of solid-state NaOH pretreatment and codigestion on methane production in the semi-dry anaerobic digestion of rose stalk

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4210-4223
Author(s):  
Yongsheng Chen ◽  
Zhijuan Ke ◽  
Yue-gan Liang
Keyword(s):  
Anaerobic Digestion ◽  
Solid State ◽  
Moisture Content ◽  
Methane Production ◽  
Biogas Production ◽  
Pig Manure ◽  
Naoh Pretreatment ◽  
Production Kinetics ◽  
Anaerobic Codigestion ◽  
Dry Anaerobic Digestion

Large quantities of burned or abandoned rose stalks are leading to serious environmental pollution. In this study, the effect of the moisture content of a solid-state NaOH pretreatment on methane production was first determined by a biochemical methane potential test. Then, the effect of codigestion with pig manure on methane production was investigated under the optimal moisture via thermophilic semi-dry anaerobic digestion by leaching bed reactor. Biogas production kinetic was assessed by the first-order kinetic model and modified Gompertz model. An increase in methane yield and biogas production kinetics was shown in the solid-state NaOH pretreated biomass. There was no significant difference in methane production for the three moisture contents studied during pretreatment (54%, 70%, and 77%). The anaerobic codigestion of rose stalk and pig manure increased 41% to 52% for methane yields and improved biogas production kinetics compared with monodigestion of rose stalk. Anaerobic codigestion did not greatly change the process stability, except for NH4+-N. The optimal process for the anaerobic digestion of rose stalk was as follows. The rose stalk was initially pretreated via solid-state NaOH pretreatment with a moisture content of 70%. Then, the pretreated rose stalk was co-digested with pig manure at a total solids ratio of 1:1.

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.

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