Effect of the Organic Loading Rate Increase and the Presence of Zeolite on Microbial Community Composition and Process Stability During Anaerobic Digestion of Chicken Wastes

Abstract

This study investigates the effect of the organic loading rate (OLR) increase from 1.0 to 3.5 g VS L(-1) day(-1) at constant hydraulic retention time (HRT) of 35 days on anaerobic reactors' performance and microbial diversity during mesophilic anaerobic digestion of ammonium-rich chicken wastes in the absence/presence of zeolite. The effects of anaerobic process parameters on microbial community structure and dynamics were evaluated using a 16S ribosomal RNA gene-based pyrosequencing approach. Maximum 12 % of the total ammonia nitrogen (TAN) was efficiently removed by zeolite in the fixed zeolite reactor (day 87). In addition, volatile fatty acids (VFA) in the fixed zeolite reactor accumulated in lower concentrations at high OLR of 3.2-3.5 g VS L(-1) day(-1). Microbial communities in the fixed zeolite reactor and reactor without zeolite were dominated by various members of Bacteroidales and Methanobacterium sp. at moderate TAN and VFA levels. The increase of the OLR accompanied by TAN and VFA accumulation and increase in pH led to the predominance of representatives of the family Erysipelotrichaceae and genera Clostridium and Methanosarcina. Methanosarcina sp. reached relative abundances of 94 and 57 % in the fixed zeolite reactor and reactor without zeolite at the end of the experimental period, respectively. In addition, the diminution of Synergistaceae and Crenarchaeota and increase in the abundance of Acholeplasmataceae in parallel with the increase of TAN, VFA, and pH values were observed.

What could the entire cornstover contribute to the enhancement of waste activated sludge acidification? Performance assessment and microbial community analysis

“…As one of class Bacteroidia , Paludibacter reached the highest abundance in S (4%), which was commonly considered to be a strictly anaerobic, HPr—producing bacterium [42]. Mangroviflexu (belonging to class Marinilabiaceae ), which was also mainly detected in S (7%), was an obligately anaerobic mesophilic microorganisms and be able to ferment various substrates with the production of HPr, HAc, and succinate [43]. This was a good explanation for the higher produced HPr in CS_S conditioning test than that in H and HS (Figs.…”

Comparative Analysis of Methanogenic Communities in Different Laboratory-Scale Anaerobic Digesters

“…accumulated during the reactor operation at increasing OLR (up to 2.84 g VS  L −1 day −1 ; Table S1, SI). However, the prevalence of Methanosarcina in reactors utilizing chicken manure as the sole substrate and operating at high TAN/FAN levels was also reported [46, 47], indicating that substrate differences and the inoculum used to start the process might have a crucial impact on the development of microorganisms. In addition, reactor R3.1 operated at high levels of VFA (primarily of acetate and propionate, up to 9.9 g L −1 and 4.1 g L −1 , accordingly).…”

“…Interestingly, Methanobacterium with T-RF 464/465 negatively correlated with TAN level, pH, and CH 4 content ( p < 0.001), while Methanobacteriaceae with T-RF 471 only negatively correlated with temperature ( p < 0.001). Members of the family Methanobacteriaceae were detected in different anaerobic digesters (e.g., [23, 46]) as well as other environments [56] and in parallel with Methanomicrobiales representatives (e.g., Methanoculleus ) they were reported to be involved in the SAO process at high ammonia levels (>2.8 g TAN L −1 ) [49]. Therefore, SAO can also be assumed in reactors R4.19 and R4.20 fed with Jatropha biomass which operated at elevated levels of TAN (3.2–3.8 g L −1 ; Table S1, SI).…”

Enhancing Anaerobic Digestion: The Effect of Carbon Conductive Materials

“…Zeolites have been traditionally studied in digestions systems to enhance the performance of reactors with high nitrogen levels thanks to its natural capacity to exchange cations (Ca 2+ and Mg 2+ ) and remove ammonium [99][100][101]. The use of bentonite was tested by Angelidaki and co-workers [102] for reducing the inhibitory effect of long chain fatty acids.…”