Semi-continuous co-digestion of sludge, fallen leaves, and grass performance

Anaerobic co-digestion of linen, sugar beet pulp, and wheat straw with cow manure: effects of mixing ratio and transient change of co-substrate

“…Table 4 also shows the lag times of between 4 and 5 days observed for the various mixes tested, demonstrating that this parameter depends more on the nature of the substrates than on their percentage in the mix. In cases using other types of substrates, such as activated sludge, longer lag times of around 15 days have been observed [10,11], confirming this result. It is also observed that maximum biogas productivity is obtained for the 50/25/25 mix, with an estimated CMY value of 378.6 mL/g VS add and a maximum methane production rate (Rm) of 20.02 ml /gVS add /day.…”

“…1) proposed by [22] is used to describe the kinetics of methane production. This model has been used by several authors where the biogas production has a lag phase, enabling prediction of the adaptation phase prior to methane production, when the substrate presents a high concentration of the less-biodegradable compounds [10,11,19].…”

“…The curves were estimated using Eq. 1, which predicts two-phase anaerobic digestion: an initial phase of biogas production from the easily-biodegradable material, and a second phase of degradation of the material after it has been subjected to a biological hydrolysis step, and with a time lag λ between the two phases [10,11]. As a first observation, this model provides a good description of the AD of the various mixes,the presence of an agricultural substrate in the mix explains the inflection point corresponding to the lag phase prior to biogas production.…”

Enhancing Methane Yield in Anaerobic Co-Digestion of Primary Sewage Sludge: A Comprehensive Review on Potential Additives and Strategies

“…The obtained efficiency was three times higher than that of single PS digestion. Subsequently, Elsayed et al [31] investigated the co-digestion of primary sludge with fallen leaves (FL) and grass (GR), focusing on the impact of the C/N ratio on methane production. The experimental results showed that a C/N ratio of 13, corresponding to a ratio of PS/mix of FL and GR almost equal to 1:2 on a VS basis, showed the highest methane yield, 352 mL CH 4 /g VS, two times higher than that of primary sludge, and the shortest lag phase (about 14 d) among the C/N ratios tested.…”

Residual Forest Biomass in Pinus Stands: Accumulation and Biogas Production Potential

“…In most anaerobic digestion studies, methane yield from lignocellulosic biomass was <250 NmL g −1 volatile solids (VS). The highest methane yield values (between 100 and 250 NmL g −1 VS) have been reported for leaves (e.g., fagus, oak, and phoenix tree) and wood samples (birch and poplar) [9][10][11][12][13][14]. Other biomass samples, such as those originating from maple wood, spruce, and pine bark and leaf litter [14][15][16][17] have been found to produce low methane (between 20 and 80 NmL g −1 VS).…”