Anaerobic digestion and dewatering characteristics of mechanically disintegrated excess sludge

1997 ◽  
Vol 36 (11) ◽  
pp. 129-136 ◽  
Author(s):  
Julia Kopp ◽  
Johannes Müller ◽  
Norbert Dichtl ◽  
Jörg Schwedes
Keyword(s):  
Anaerobic Digestion ◽  
Ball Mill ◽  
Anaerobic Degradation ◽  
Excess Sludge ◽  
Particle Structure ◽  
Disintegration Rate ◽  
Digestion Time ◽  
Stirred Ball Mill ◽  
High Pressure Homogenizer ◽  
Cell Disintegration

Mechanical cell disintegration and its influence on anaerobic digestion was investigated using four different methods. Methods to describe the degree of cell-disruption were developed and the release of organic components into the sludge water was measured. The best results were optained using a stirred ball mill and a high-pressure homogenizer. The influence of disintegration rate and digestion time on the performance of the anaerobic process and the dewatering characteristics were investigated. The degradation is accelerated and the digestion time can be reduced, especially when using immobilised microorganisms. It could be shown that the mechanical disintegration results in a disruption of particle structure and an increase of polymer-demand. As a result of better anaerobic degradation the density and dewatering results of disintegrated sludges are improved in comparison to non-treated sludges.

Disintegration of sewage sludges and influence on anaerobic digestion

1998 ◽  
Vol 38 (8-9) ◽  
pp. 425-433 ◽  
Author(s):  
J. Müller ◽  
G. Lehne ◽  
J. Schwedes ◽  
S. Battenberg ◽  
R. Näveke ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Particle Structure ◽  
Digestion Time ◽  
Digested Sludge ◽  
Anaerobic Process ◽  
Stirred Ball Mill ◽  
High Pressure Homogenizer ◽  
Micro Organisms ◽  
Degree Of Degradation ◽  
Cell Disintegration

The improvement of anaerobic digestion was investigated in an interdisciplinary research group. Using four different methods of mechanical cell disintegration the influence of the degree of disintegration and the digestion parameters on the performance of the anaerobic process was investigated. Analytical methods to describe the degree of cell-disruption had to be developed. The best results were obtained using a stirred ball mill and a high-pressure homogenizer. As a result of disintegration the degradation is accelerated and the digestion time can be reduced, especially when using immobilized micro-organisms. The treatment of digested sludge by ozonization respectively by mechanical disintegration led to an improved biodegradability of residual organic compounds. In a following second anaerobic process the treated sludge reached an even higher degree of degradation. On the other hand the disruption of the particle structure leads to an increase in polymer-demand and no improvement in dewatering results. Sludge water, returned to the aeration tanks, is slightly more polluted, especially the concentration of ammonia increases because of the better anaerobic digestion.

Mechanism Study of Excess Sludge Disintegration by Stirred Ball Mill

2012 ◽  
Vol 518-523 ◽  
pp. 3403-3407 ◽  
Author(s):  
Jin Chi Liu ◽  
Tong Zhu ◽  
Jie Li ◽  
Zhan Min He ◽  
Yi Ming Zhang ◽  
...  
Keyword(s):  
Ball Mill ◽  
Large Scale ◽  
Mechanism Study ◽  
Excess Sludge ◽  
Disintegration Rate ◽  
Disintegration Time ◽  
Stirred Ball Mill

Stirred ball mill(SBM) method is one of the usually method which applied in large scale application cases of sludge disintegration. This study focuses on investigation the mechanism of sludge disintegration by SBM method. Besides analysis general indicators of SCOD, TN, TP and calculated the disintegration rate of COD (DDCOD). The result indicated the SCOD and DDCOD increased with the disintegration time. As DDCOD increased to the highest of 18.6% at the treated time of 60min, it shown that SBM was not more efficient in disintegration of biomass into so smaller particle that easily dissolved in water.

Effects of disintegration on anaerobic degradation of sewage excess sludge in downflow stationary fixed film digesters

2000 ◽  
Vol 41 (3) ◽  
pp. 171-179 ◽  
Author(s):  
M. Engelhart ◽  
M. Krüger ◽  
J. Kopp ◽  
N. Dichtl
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Soluble Proteins ◽  
Excess Sludge ◽  
Mechanical Pretreatment ◽  
Volatile Solids ◽  
Fixed Film ◽  
High Pressure Homogenizer ◽  
Anaerobic Digestibility

The effects of mechanical disintegration on anaerobic digestibility of sewage excess sludge in downflow stationary fixed film (DSFF) digesters were investigated on laboratory scale. Mechanical pretreatment using a high pressure homogenizer led to significantly enhanced concentrations of soluble proteins and carbohydrates in the feed sludge. Using DSFF digesters with two different tubular plastic media as support material it was shown that a stable digestion process could be achieved at hydraulic retention times (HRT) down to 5 days. Compared to conventional digesters at 10 d and 15 d HRT respectively, the degradation of volatile solids was enhanced up to 25%, also resulting in a higher specific biogas production. Further investigations on degradation of soluble proteins and carbohydrates showed that a slowly degradable fraction of carbohydrates was released via disintegration. Using the distribution of chain length and the concentrations of volatile fatty acids as process parameters, the dependability on the HRT and the degree of disintegration (the release of soluble COD) predominated the effects of specific surface area of the support media.

Minimisation of costs by using disintegration at a full-scale anaerobic digestion plant

2002 ◽  
Vol 46 (4-5) ◽  
pp. 405-412 ◽  
Author(s):  
A. Winter
Keyword(s):  
Anaerobic Digestion ◽  
Ball Mill ◽  
Biogas Production ◽  
Waste Water Treatment ◽  
Solid Content ◽  
Full Scale ◽  
Pollution Level ◽  
Ball Mills ◽  
Capital Costs ◽  
Stirred Ball Mill

Various half-scale and lab-scale investigations have already shown that the disintegration of excess sludge is a possible pre-treatment to optimise anaerobic digestion. To control these results different methods of disintegration were investigated at a full-scale plant. Two stirred ball mills and a plant for oxidation with ozone were applied. A positive influence of disintegration on the anaerobic biodegradability can be established with application of a stirred ball mill. Biogas production as well as the degree of degradation were increased by about 20%. Laboratory investigations also validate that disintegration increases the polymer demand and leads to a lower solid content after dewatering. A higher pollution level of process water after dewatering even with ammonia and COD corroborates the results of the anaerobic degradation. Capital costs for the stirred ball mill, costs for energy, manpower and maintenance can be covered if the specific costs for disposal are high. If the development of costs in future and the current discussion about sludge disposal are taken into account sewage sludge disintegration can be a suitable technique to minimise costs at waste water treatment plants.

Research on the stability of heavy metals (Cu, Zn) in excess sludge with the pretreatment of thermal hydrolysis

2015 ◽  
Vol 73 (4) ◽  
pp. 890-898 ◽  
Author(s):  
Huimin Wu ◽  
Meng Li ◽  
Lei Zhang ◽  
Chao Sheng
Keyword(s):  
Heavy Metals ◽  
Anaerobic Digestion ◽  
Chemical Speciation ◽  
Stable Form ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
The Stability ◽  
Cu And Zn

Thermal hydrolysis (TH) has been used to improve anaerobic digestion performance as well as the stability of heavy metals in sludge. Because the toxicity of heavy metals is closely related to both the concentration and the chemical speciation, more exhaustive studies on speciation distribution are urgently needed. This research aimed to investigate the effects of TH treatment (especially the time and temperature) on the concentration and stability of heavy metals in sludge, and to define the optimal TH conditions. The TH experiment indicated that the content of the stable form of Cu and Zn reached 83% and 47.4%, respectively, with TH at 210°C and 30 min. Compared with the raw sludge, the proportion of Cu and Zn increased by 11.88% and 7.3%, respectively. Results indicated that the heavy metals were combined with sludge in a more stable form with the pretreatment of TH, which improved the stability of heavy metals.

Anaerobic Digestion of Piggery Wastes

1992 ◽  
Vol 25 (1) ◽  
pp. 9-16 ◽  
Author(s):  
A. D. Andreadakis
Keyword(s):  
Anaerobic Digestion ◽  
Anaerobic Degradation ◽  
Gas Production ◽  
Feasible Method

Anaerobic digestion can be an attractive and economically feasible method for the treatment of piggery wastes, provided that maximization of gas production and efficient subsequent utilization can be attained. Expedience from anaerobic digestion of domestic sludges can not be directly transferred to the design of digestion treating piggery wastes, due to the particular characteristics of the latter. The sequential anaerobic degradation of these wastes favours the adoption of short retention times for maximum gas production while at the same time satisfactory stabilization can be obtained.

Sludge accumulation and methanogenic activity in an anaerobic lagoon

2000 ◽  
Vol 42 (10-11) ◽  
pp. 247-255 ◽  
Author(s):  
J. Paing ◽  
B. Picot ◽  
J. P. Sambuco ◽  
A. Rambaud
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Methanogenic Activity ◽  
Start Up ◽  
Anaerobic Lagoon ◽  
Methane Production Rate ◽  
Sludge Accumulation

Sludge accumulation and the characteristics of anaerobic digestion in sludge had been investigated in a primary anaerobic lagoon. Methanogenic potential of sludge was evaluated by an anaerobic digestion test which measured the methane production rate. Sludge was sampled at several points in the lagoon to determine spatial variations and with a monthly frequency from the start-up of the lagoon to observe the development of anaerobic degradation. Maximum amounts of sludge accumulated near the inlet. The mean methane production of sludge was 2.9 ml gVS–1 d–1. Sludge near the outlet presented a greater methanogenic activity and a lesser concentration of volatile fatty acids than near the inlet. The different stages of anaerobic degradation were spatially separated, acidogenesis near the inlet and methanogenesis near the outlet. This staged distribution seemed to increase efficiency of anaerobic fermentation compared with septic tanks. Methane release at the surface of the lagoon was estimated to be very heterogeneous with a mean of 25 l m–2 d–1. The development of performance and sludge characteristics showed the rapid beginning of methanogenesis, three months after the start-up of the anaerobic lagoon. Considering the volume of accumulated sludge, it could however be expected that methanogenic activity would further increase.

scholarly journals Remove and recover phosphorus during anaerobic digestion of excess sludge by adding waste iron scrap

2013 ◽  
Vol 78 (2) ◽  
pp. 303-312 ◽  
Author(s):  
Wei Zheng ◽  
Xiao Li ◽  
Dong Wang ◽  
Qi Yang ◽  
Kun Luo ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Excess Sludge ◽  
Iron Scrap
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