Combined high-rate contact stabilization and chemically enhanced primary treatment for enhanced recovery of organic matter and biogas from sewage.

This study examined integrating high-rate contact stabilization (HRCS) and chemically enhanced primary treatment (CEPT) for wastewater to improve the carbon recovery rate (CRR). Enhancing chemical oxygen demand (COD) removal efficiency was hypothesized to improve the CRR. The evaluation covered serial HRCS-CEPT, serial CEPT-HRCS, and single-stage carbon recovery (Single-CR).

Magnetite particles accelerate methanogenic degradation of highly concentrated acetic acid in anaerobic digestion process.

The anaerobic digestion (AD) process has become significant for its capability to convert organic wastewater into biogas, a valuable energy source. Excessive acetic acid accumulation in the anaerobic digester can inhibit methanogens, ultimately leading to the deterioration of process performance. Herein, the effect of magnetite particles (MP) as an enhancer on the methanogenic degradation of highly-concentrated acetate (6 g COD/L) was examined through long-term sequential AD batch tests.

Key players in syntrophic propionate oxidation revealed by metagenome-assembled genomes from anaerobic digesters bioaugmented with propionic acid enriched microbial consortia.

Propionic acid (HPr) is frequently accumulated in anaerobic digesters due to its thermodynamically unfavorable degradation reaction. Here, we identify key players in HPr oxidation and organic overloading recovery from metagenome-assembled genomes (MAGs) recovered from anaerobic digesters inoculated with HPr-enriched microbial consortia before initiating organic overloading. Two independent HPr-enrichment cultures commonly selected two uncultured microorganisms represented with high relative abundance: sp002497965 and JABUEY01 sp013314815 (a member of the family).

Effect of magnetite supplementation on mesophilic anaerobic digestion of phenol and benzoate: Methane production rate and microbial communities.

Anaerobic sequential batch tests treating phenol and benzoate were conducted to evaluate the potential of magnetite supplementation to improve methanogenic degradation of phenol and benzoate, and to identify active microbial communities under each condition. Specific CH production rates during anaerobic digestion were 218.5 mL CH/g VSS/d on phenol and 517.

Effects of inhibitions by sodium ion and ammonia and different inocula on acetate-utilizing methanogenesis: Methanogenic activity and succession of methanogens.

Acetate-fed anaerobic sequential batch experiments with four different inhibitory conditions (non-inhibitory (Lo), sodium-ion inhibitory (Na), ammonia inhibitory (Am), combined inhibitory (Hi)) were conducted using thirteen different inocula to investigate the inhibition effects by sodium-ion and ammonia and different inocula on acetate-utilizing methanogenesis and succession of methanogens. Sodium-ion and ammonia significantly extended lag-time λ and reduced specific-methanogenic-activity R, and caused synergistic inhibition. The inhibition differed according to the initial methanogen community structures: the inhibition effects on λ and R were strongest ininocula with Methanosaeta concilii dominant and weakest in inocula with Methanoculleus bourgensis dominant.

A snapshot of microbial community structures in 20 different field-scale anaerobic bioreactors treating food waste.

This study aimed to identify significant factors shaping the microbial populations in biogas plants treating food waste (FW). Twenty full-scale anaerobic acidogenic/methanogenic bioreactors, located at 11 FW treatment facilities, were compared to find patterns in their microbial community structures and potential interactions with the process parameters. Temperature, hydraulic retention time, and organic loading rate were design parameters that systematically influenced the microbial communities.

Magnetite as an enhancer in methanogenic degradation of volatile fatty acids under ammonia-stressed condition.

Anaerobic batch tests with a 2 full-factorial design of ammonia (1.5, 6.5 g N/L) and magnetite concentrations (0, 20 mmol/L) were conducted separately for methanogenic degradation of acetate, propionate, and butyrate (volatile fatty acids (VFAs)) to 1) quantify the effect of magnetite as an enhancer in methanogenic degradation of each of the VFAs in conditions without ammonia stress (1.

Single and combined inhibition of Methanosaeta concilii by ammonia, sodium ion and hydrogen sulfide.

Single and combined inhibition of lag time λ and specific methanogenic activity R of Methanosaeta concilii by NH, Na and HS were investigated using inhibition tests with a single inhibitor and a 3 full-factorial experiment of NH, Na and HS concentrations (1.5 ≤ total ammonia nitrogen (TAN)/L ≤ 4.5 g, 1 ≤ Na/L ≤ 4.

Development of an interspecies interaction model: An experiment on Clostridium cadaveris and Clostridium sporogenes under anaerobic condition.

The specific primer and probe sets for quantifying Clostridium cadaveris and Clostridium sporogenes using a quantitative real-time PCR were designed. Each primer and probe set detected only the target species very specifically. The two species were cultivated in pure and mixed culture in batch mode with glucose as the only carbon source.

Comprehensive analysis of microbial communities in full-scale mesophilic and thermophilic anaerobic digesters treating food waste-recycling wastewater.

Microbes were sampled for a year in a full-scale mesophilic anaerobic digester (MD) and a thermophilic anaerobic digester (TD) treating food waste-recycling wastewater (FRW), then microbial community structure, dynamics and diversity were quantified. In the MD, Fastidiosipila, Petrimonas, vadinBC27, Syntrophomonas, and Proteiniphilum were dominant bacterial genera; they may contribute to hydrolysis and fermentation. In the TD, Defluviitoga, Gelria and Tepidimicrobium were dominant bacteria; they may be responsible for hydrolysis and acid production.

Microbial communities underpinning mesophilic anaerobic digesters treating food wastewater or sewage sludge: A full-scale study.

Ten mesophilic full-scale anaerobic digesters treating food wastewater (FW-digesters) or sewage sludge (SL-digesters) were monitored for 1 year to investigate: (1) microbial communities underpinning FW-digesters and SL-digesters, (2) the effects of total ammonia-nitrogen concentration [TAN] and Na concentration [Na] on variations of these communities. [TAN] and [Na] in the digester varied among digesters: 1.7-6.

Temporal variation in bacterial and methanogenic communities of three full-scale anaerobic digesters treating swine wastewater.

To investigate the effects of temporal variations of process parameters on microbial community structures in the two types of full-scale anaerobic digester treating swine wastewater, three full-scale anaerobic digesters were monitored. An anaerobic filter (AF)-type digester located in Gong-Ju (GJ) showed the highest COD removal among three digesters and maintained stable efficiency. A digester in Hong-Seong (HS) was of the same type as it GJ and showed improved efficiency over the sampling period.

A comparative study on the process efficiencies and microbial community structures of six full-scale wet and semi-dry anaerobic digesters treating food wastes.

The purpose of this study was to investigate the effect of different types of food wastes on the process efficiency and microbial community structures in full-scale anaerobic digesters and to identify parameters that affect these criteria. Six full-scale anaerobic digesters were investigated; three were operated under "wet" condition (total solids TS≤10%), and three were run under "semi-dry" condition (10%≤TS≤20%). Removal efficiency of volatile solids was much higher in the wet digesters (75.

Bacteria and archaea communities in full-scale thermophilic and mesophilic anaerobic digesters treating food wastewater: Key process parameters and microbial indicators of process instability.

In this study, four different mesophilic and thermophilic full-scale anaerobic digesters treating food wastewater (FWW) were monitored for 1-2years in order to investigate: 1) microbial communities underpinning anaerobic digestion of FWW, 2) significant factors shaping microbial community structures, and 3) potential microbial indicators of process instability. Twenty-seven bacterial genera were identified as abundant bacteria underpinning the anaerobic digestion of FWW. Methanosaeta harundinacea, M.

Microbial community shifts in a farm-scale anaerobic digester treating swine waste: Correlations between bacteria communities associated with hydrogenotrophic methanogens and environmental conditions.

Microbial community structure in a farm-scale anaerobic digester treating swine manure was investigated during three process events: 1) prolonged starvation, and changes of 2) operating temperature (between meso- and thermophilic) and 3) hydraulic retention time (HRT). Except during the initial period, the digester was dominated by hydrogenotrophic methanogens (HMs). The bacterial community structure significantly shifted with operating temperature and HRT but not with long-term starvation.

Identifying methanogen community structures and their correlations with performance parameters in four full-scale anaerobic sludge digesters.

Four full-scale mesophilic anaerobic digesters treating waste sludge were monitored to characterize methanogen communities and their relationship with process parameters. The performance of the four digesters were dissimilar with the average chemical oxygen demand removal efficiencies between 24 and 45% and differing pH. Real-time quantitative PCR showed that archaeal 16S rRNA gene concentration ([ARC]) and, more pronouncedly, its ratio to bacterial counterpart ([ARC]/[BAC]) correlated positively with the performance parameters, including the lipid removal efficiency.

Characterization of antibiotic resistance genes in representative organic solid wastes: Food waste-recycling wastewater, manure, and sewage sludge.

In this research, the distribution of antibiotic resistance genes (ARGs) was characterized in representative organic solid waste (OSW) in Korea: food waste-recycling wastewater (FRW), manure, and sewage sludge. The amounts of total ARG (gene copies/16S rRNA gene copies) was greatest in manure followed by sewage sludge and FRW. Interestingly, there were significantly different patterns in the diversity and mechanisms of ARGs.

Mesophilic Acidogenesis of Food Waste-Recycling Wastewater: Effects of Hydraulic Retention Time, pH, and Temperature.

The effects of hydraulic retention time (HRT), pH, and operating temperature (T ) on the degradation of food waste-recycling wastewater (FRW) were investigated in laboratory-scale hydrolysis/acidogenesis reactors. Response surface analysis was used to approximate the production of volatile organic acids and degradation of volatile suspended solids (VSS), carbohydrate, protein, and lipid with regard to the independent variables (1 ≤ HRT ≤ 3 days, 4 ≤ pH ≤ 6, 25 ≤ T  ≤ 45 °C). Partial cubic models adequately approximated the corresponding response surfaces at α < 5 %.

Correlations between bacterial populations and process parameters in four full-scale anaerobic digesters treating sewage sludge.

Process parameters and bacterial populations were investigated in four full-scale anaerobic digesters treating sewage sludge. Although the four digesters were operated under similar conditions, digesters A and B had higher pH (7.2-7.

Nutrient Recovery of Starch Processing Waste to Cordyceps militaris: Solid State Cultivation and Submerged Liquid Cultivation.

This study demonstrated the potential for managing starch processing waste (SPW) by bioconversion to Cordyceps militaris mycelia using solid state cultivation (SSC) and submerged liquid cultivation (SLC). The growth characteristics of C. militaris mycelium were accessed and compared for SSC and SLC systems on SPW under various conditions of initial SPW concentration, pH, and operating temperature.

Nitrification resilience and community dynamics of ammonia-oxidizing bacteria with respect to ammonia loading shock in a nitrification reactor treating steel wastewater.

The aim of this study was to investigate the nitrification resilience pattern and examine the key ammonia-oxidizing bacteria (AOB) with respect to ammonia loading shocks (ALSs) in a nitrification bioreactor treating steel wastewater. The perturbation experiments were conducted in a 4-L bioreactor operated in continuous mode with a hydraulic retention time of 10 d. Three sequential ALSs were given to the bioreactor (120, 180 and 180 mg total ammonia nitrogen (TAN)/L.

Anaerobic digestion of cattle offal: protein and lipid-rich substrate degradation and population dynamics of acidogens and methanogens.

Anaerobic digestion of cattle offal was investigated in batch reactors at 35 °C to determine the feasibility of using cattle offal as a feedstock. The organic content [i.e.

Characterization of food waste-recycling wastewater as biogas feedstock.

A set of experiments was carried out to characterize food waste-recycling wastewater (FRW) and to investigate annual and seasonal variations in composition, which is related to the process operation in different seasons. Year-round samplings (n=31) showed that FRW contained high chemical oxygen demand (COD; 148.7±30.

Resource recovery using whey permeate to cultivate Phellinus linteus mycelium: Solid-state and submerged liquid fermentation.

The growth characteristics of Phellinus linteus mycelium were assessed and compared under solid-state fermentation (SSF) and submerged liquid fermentation (SLF) systems on whey permeate medium. Response surface methodology was used to investigate the growth rates of mycelia under various conditions of operating temperature (TO), initial pH, and substrate concentration ([S]). The optimal growth conditions of P.

Temporal variation in methanogen communities of four different full-scale anaerobic digesters treating food waste-recycling wastewater.

Methanogen communities were investigated using 454 pyrosequencing in four different full-scale anaerobic digesters treating food waste-recycling wastewater. Seasonal samples were collected for 2 years, and 24 samples were available for microbial analysis from a plug flow thermophilic (PT) digester, a continuously-stirred tank thermophilic (CT) digester, an upflow anerobic sludge blanket mesophilic (UM) digester, and a continuously-stirred tank mesophilic (CM) digester. Methanoculleus, Methanobacterium, Methanothermobacter, and Methanosaeta were revealed to be key methanogens in full-scale anaerobic digestion process treating food waste-recycling wastewater.