Effects of humic matter on the anaerobic digestion of sewage sludge: New insights from sludge structure

Improvement of Methane Production and Sludge Dewaterability by FeCl3-Assisted Anaerobic Digestion of Aluminum Waste-Activated Sludge

“…The D f value of the digested sludge decreased after adding FeCl 3 . As reported in ref , a lower D f value indicates a lower self-similarity of sludge, looser sludge particles, and higher fluidity of organic molecules. Therefore, it was concluded that the addition of FeCl 3 substantially changed the physical structure of the sludge particles, reduced the degree of self-similarity, and improved molecular mobility of the sludge.…”

Evaluating the Effects of Aged Fe-Enhanced Primary Sedimentation Sludge on Methane Production from Aluminum-Waste Activated Sludge during Anaerobic Digestion

“…The fractal dimension ( D f ) of sludges is usually used to describe the physical structure of sludges. Higher D f values indicate more compact sludge particles. , The D f of CEPS sludges at different aging times is shown in Figure . The physical structure of the sludges was highly affected by the aging time.…”

Suppression of Methane Generation during Methanogenesis by Chemically Modified Humic Compounds

“…Under conditions of a semi-continuous process of methanogenesis, an increase in the concentration of HC in the medium up to 20 HS/VSS also led to a decrease in the formation of biogas by 56% and the average fraction of CH 4 in it—by 6.8% [ 14 ]. In one another study, a decrease in CH 4 synthesis from 337.7 ± 1.5 mL CH 4 /g VS (volatile solids) to 144.3 ± 0.7 mL CH 4 /g VS was noted in samples of anaerobic sludge when humic acid sodium salt (AR, Aladdin) was added to the medium at a concentration of 0.6 g HM (humic matter)/g VS [ 15 ]. Thus, these results confirm that HC does indeed inhibit energy conversion efficiency in anaerobic digestion systems.Comparing the known results with the data obtained in this work, it can be argued that by chemical modification of HC, based on the use of knowledge about the reduction of methane emission under natural conditions (swamps), it is possible to obtain samples of HC derivatives, the use of which makes it possible to influence the composition of biogas formed under the action of anaerobic consortia, towards a significant decrease in the proportion of CH 4 (in some cases, up to 100%).…”

“…To date, there are a number of studies devoted to the decrease under the influence of HC in the efficiency of methanogenesis, catalyzed by various anaerobic methanogenic consortia [ 11 , 12 , 13 , 14 , 15 ]. Using four different methanogenic consortia as an example, we also have previously revealed that the introduction of natural humic acids (HA) into the media at a concentration of up to 10 g/L leads to a decrease in the general energy status of microbial cells, which indicates the inhibition of their metabolic processes.…”