Increase of anaerobic degradation of particulate organic matter in full-scale biogas plants by mechanical maceration

2000 ◽  
Vol 41 (3) ◽  
pp. 145-153 ◽  
Author(s):  
H. Hartmann ◽  
I. Angelidaki ◽  
B.K. Ahring
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Anaerobic Degradation ◽  
Separation Unit ◽  
Fiber Separation ◽  
Operational Costs ◽  
Mechanical Pretreatment ◽  
Fiber Size ◽  
Before And After ◽  
Biogas Plants

Different concepts of implementation of mechanical pretreatment for enhancing the biogas potential from fibers in manure feedstock were valuated by sampling before and after macerators at different biogas plants and from a fiber separation unit. An increase of the biogas potential of up to 25% by pretreatment of the whole feed in the macerator before the reactor was observed. Implementation concepts with a treatment of the fibers alone after separation from the manure showed to be not efficient due to a low recovery of organic matter in the fibers by the separation unit. The low operational costs of a macerator make it attractive to use this pretreatment method for a more complete degradation of particulate organic matter. Investigation of the size distribution of the fibers showed that a change in biogas potential was not correlated to a smaller size of the fibers. Results from the macerators indicate that the biodegradability of the fibers is rather enhanced by shearing which is not necessarily reflected by a change in fiber size.

Long-term dynamics of organic matter and elements exported as coarse particulates from two Caribbean montane watersheds

2012 ◽  
Vol 28 (2) ◽  
pp. 127-139 ◽  
Author(s):  
T. Heartsill Scalley ◽  
F. N. Scatena ◽  
S. Moya ◽  
A. E. Lugo
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Headwater Streams ◽  
Structural Complexity ◽  
Base Flow ◽  
Coarse Particulate Organic Matter ◽  
North East ◽  
Storm Flow ◽  
Before And After

Abstract:In heterotrophic streams the retention and export of coarse particulate organic matter and associated elements are fundamental biogeochemical processes that influence water quality, food webs and the structural complexity of forested headwater streams. Nevertheless, few studies have documented the quantity and quality of exported organic matter over multiple years and under a range of conditions that includes both droughts and hurricanes. This study quantifies the export of coarse particulate organic matter (CPOM, > 12.7 mm), over 18 y in two headwater streams in north-east Puerto Rico. Daily exports ranged from 0 to over 170 g ha−1 d−1 and averaged 7.39 g ha−1 d−1, with similar amounts coming from leaves (3.5 g ha−1 d−1) and wood (3.2 g ha−1 d−1). Export of coarse particulate organic carbon was 3.0 g ha−1 d−1 which constitutes only 1.32% of carbon exports. Most litter falling into the streams was processed in place as only 2.3% of the leaf litter falling directly into these perennial channels was exported as CPOM. On average, 6 wk y−1 had no exports while events transporting more than 10 g ha−1 d−1 occurred every 2.8 mo. Instead of a single annual pulse as observed in deciduous systems, there were annual peaks in CPOM exports during May and September and less export during the drier period from December to February. Ratios of C:N in the exported material were highest in the driest month and lowest during rainy months, while leaf fluxes for nitrogen, phosphorus and calcium were highest in rainy months and lowest during February. Although median daily exports and exports during low- and base-flow periods were similar before and after Hugo, after 16 y exports during moderate- and high-flow periods were still less than those in the 2 y prior to the hurricane. Our observations indicate a system with high rates of internal processing that quickly returns to median daily conditions following hurricanes but requires several decades for storm-flow exports to return to pre-disturbance conditions and indicates that the long-term pattern of CPOM export is associated with the level of maturity of watershed vegetation.

Effect of Impoundment and River Diversion on Profundal Macrobenthos of Southern Indian Lake Manitoba

1984 ◽  
Vol 41 (4) ◽  
pp. 638-648 ◽  
Author(s):  
Allen P. Wiens ◽  
David M. Rosenberg
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Particulate Organic Matter ◽  
Standing Crop ◽  
Suspended Solids ◽  
Shoreline Erosion ◽  
Benthic Organism ◽  
River Diversion ◽  
Before And After ◽  
High Diversity

Profundal macrobenthos in Southern Indian Lake, Manitoba, were surveyed to determine effects of hydroelectric manipulations in 1972 (preimpoundment), 1977 (postimpoundment), and 1979 (postdiversion). Lakewide average standing crops increased following impoundment and decreased by 3 yr after impoundment. Regional changes in standing crops usually could be related to additions of nutrients leached from flooded vegetation, additions of particulate organic matter resulting from shoreline erosion, and changes in integral primary production and suspended solids concentrations before and after impoundment. Greater increases in standing crops of macrobenthos in shallower compared with deeper depth zones of the lake after flooding were attributed to preferential deposition of organic materials in the shallow areas of the lake. Mean standing crops of macrobenthos were higher in regions through which the Churchill River flowed than in regions isolated from the flow before and after impoundment. After diversion, greatest decreases in standing crops occurred in isolated regions, whereas those of regions in the flow declined much less or increased. Responses of the most abundant taxa of macrobenthos (Pontoporeia brevicornis grp., Chironomidae, Oligochaeta, Sphaeriidae) differed in many ways from those recorded for other new reservoirs. Pontoporeia brevicornis grp. remained the most abundant benthic organism, there was no evident succession of macrobenthic taxa, and a high diversity of profundal species was maintained. These results, together with the slight changes in standing crop observed after flooding, indicated only a marginal impact on macrobenthos caused by the low-level flooding of Southern Indian Lake.

Anaerobic degradation kinetics of particulate organic matter: a new approach

1997 ◽  
Vol 36 (6-7) ◽  
pp. 239-246 ◽  
Author(s):  
Andrea Valentini ◽  
Gilbert Garuti ◽  
Alberto Rozzi ◽  
Andrea Tilche
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Anaerobic Degradation ◽  
Degradation Kinetics ◽  
Kinetic Constant ◽  
Power Coefficient ◽  
Mathematical Representation ◽  
First Order ◽  
Batch Tests ◽  
Kinetics Of

The development of a reliable model of anaerobic hydrolysis is of primary importance for improving modeling and design of anaerobic treatment for wastewaters and slurries with high suspended solids concentration. Michaelis-Menten, substrate first order, substrate and biomass first order and substrate first order and biomass half order equations have been compared using experimental data from a series of anaerobic degradation batch tests on cellulose particles of known size. A general kinetic equation [dS/dt=−KHASXA] which may include all the four considered kinetics, is presented. This general equation allows for a more accurate mathematical representation of the hydrolysis process. Analysing data from a series of batch tests, the best fit value of A was found to be in the range 0.42 to 0.64. This approach could reduce the choice of anaerobic degradation kinetics of particulate organic matter to the calculation of the kinetic constant KHA and of the related power coefficient A.

Relating particulate organic matter-nitrogen (POM-N) and non-POM-N with pulse crop residues, residue management and cereal N uptake

Agronomie ◽  
2002 ◽  
Vol 22 (7-8) ◽  
pp. 777-787 ◽  
Author(s):  
Graeme D. Schwenke ◽  
Warwick L. Felton ◽  
David F. Herridge ◽  
Dil F. Khan ◽  
Mark B. Peoples
Keyword(s):  
Organic Matter ◽  
Particulate Organic Matter ◽  
Crop Residues ◽  
N Uptake ◽  
Residue Management ◽  
Pulse Crop
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