음폐수의 혐기성 소화 효율 향상을 위한 열가수분해 하수슬러지와 병합처리성 검토

허준 대한상하수도학회 2022 상하수도학회지 Vol.36 No.6

The object of this study is to feasibility assesment for co-digestion efficiency of food waste recycling wastewater(FWR) with thermal hydrolysis process dehydration cake (THP Sludge). As a result of THP pre-treatment experimental conditions to 160 o C and 30 minutes, the solubility rate(conversion rate of TCOD to SCOD) of the THP sludge increased by 34%. And the bio-methane potential in the THP sludge increased by about 1.42 times from 0.230 to 0.328 m 3 CH 4 /kg VS compared to the non-pre-treatment. The substrates of the co-digestion reactor were FWR and THP sludge at a 1:1 ratio. Whereas, only FWR was used as a substrate in the digestion reactor as a control group. The experimental conditions are 28.5 days of hydraulic retention time(HRT) and 3.5 kg VS/m 3 -day of organic loading rate(OLR). During the 120 days operation period, the co-digestion reactor was able to operate stably in terms of water quality and methane production, but the FWR digestion reactor deteriorated after 90 days, and methane production decreased to 0.233 m 3 CH 4 /kg VS, which is 67% of normal condition. After 120 days of the experiment, organic loading rate(OLR) of co-digestion reactor was gradually increased to 4.5 kg VS/m 3 -day and operated for 80 days. Methane production during 80 days was evaluated to be good at the level of 0.349 m 3 CH 4 /kg VS. As a result of evaluating the dehydration efficiency of the sludge before/after 150-180 o C THP using a filter press, it was confirmed that the moisture content of the sludge treated before THP at 180 o C was 75% and improved by 8% from 83-85% level. Therefore, it is expected that the co-digestion reactor of FWR and THP sludge will ensure stable treatment water quality and increase bio-methane production and reduction effect of dehydration sludge volume.

Biomethanation of Sewage Sludge with Food Waste Leachate Via Co-Digestion

( Jingyeong Shin ),( Young Beom Kim ),( Jong Hun Jeon ),( Sangki Choi ),( In Kyu Park ),( Young Mo Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Anaerobic mono- and co-digestion of sewage sludge and food waste leachate (FWL) were performed by assessing methane production and characterizing microbial communities. Anaerobic digestion (AD) of waste activated sludge (WAS) alone produced the lowest methane (281 ml CH₄), but an approximately 80% increase in methane production was achieved via co-digestion of WAS and FWL (506 ml CH₄). There were less differences in the diversity of bacterial communities in anaerobic digesters, while archaeal (ARC) and bacterial (BAC) amounts reflected AD performance. Compared with the total ARC and BAC amounts in the mono-digestion of WAS, the ARC and BAC amounts increased two and three times, respectively, during co-digestion of FWL and WAS. In characterized archaeal communities, the dominant ratio of hydrogenotrophic methanogens in the mono-digestion of WAS approached nearly a 1:1 ratio of the two acetoclastic and hydrogenotrophic methanogens in the co-digestion of FWL and WAS. The ARC/BAC ratio in the digesters varied in the range of 5.9% to 9.1%, indicating a positive correlation with the methane production of AD.

Co-digestion of Sewage Sludge and Human Waste

( Changmin Lee ),( Byeong-chel Kim ),( Ji-hun Nab ),( Jae Young Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Low anaerobic degradability of sewage sludge has raised demands for co-digestion with other organic wastes such as food waste, livestock manure and agricultural by-products. Human waste (HW) captured from septic tanks also can be used as a co-digestion substrate through supplying of additional carbon and nutrients. In this study, the possibility of sewage sludge and HW codigestion was investigated. The specific objectives were to 1) compare CH4 generation of primary sludge (PS), excess sludge (ES), HW and their mixtures by biochemical methane potential (BMP) test; 2) identify synergistic co-digestion effects on their biodegradability; 3) elucidate the co-digestion effects based on the changes of physicochemical characteristics by mixing. The test ratios between PS, ES and HW were R1=40:60:0, R2=28:43:30, R3=24:34:42, R4=18:26:56, R5=15:23:62, R6=100:0:0 (PS control), R7=0:100:0 (ES control), R8=0:0:100 (HW control) by dry wt., respectively. The maximum mixing ratio of HW (R5) was determined based on the wet wt. ratio between PS, ES produced in a WWTP, Seoul and HW gathered in the WWTP. The BMP tests were conducted by using the same ratio of substrate to inoculum (1:2 by dry wt.) meaning that the same amount of volatile solids (VS) was added to all test assays. As a result, with the increase of HW ratio, CH₄ generation was increased. This is because the amount of carbon in the same VS of substrate was increased. CH₄ potentials were R1: 174 44, R2: 226 2, R3: 250 16, R4: 268 15, R5: 262 9, R6: 158 1, R7: 164 38, R8: 299 54 mL/g-VS. For CH₄ generation dynamics, codigestion did not affect the lag phase of CH₄ generation. The synergistic effect of co-digestion on the biodegradability, which is the ratio of maximum CH₄ generation to theoretical CH₄ potential, was identified for the mixing assays of PS, ES and HW (R2 - R5) but not for the mixing assay of PS and ES (R1). When the HW was mixed, biodegradability was enhanced by 8 - 16% compared to the weighted average considering the mixing ratio of raw samples. In conclusion, HW can be utilized as a substrate for the co-digestion of sewage sludge by replenishing carbon to increase CH₄ production. And C/N ratio can be balanced to enhance the degradability of the mixed substrate rather than each substrate.

Anaerobic co-digestion of spent coffee grounds with different waste feedstocks for biogas production

Kim, Jaai,Kim, Hakchan,Baek, Gahyun,Lee, Changsoo Elsevier 2017 Waste management Vol.60 No.-

<P><B>Abstract</B></P> <P>Proper management of spent coffee grounds has become a challenging problem as the production of this waste residue has increased rapidly worldwide. This study investigated the feasibility of the anaerobic co-digestion of spent coffee ground with various organic wastes, i.e., food waste, <I>Ulva</I>, waste activated sludge, and whey, for biomethanation. The effect of co-digestion was evaluated for each tested co-substrate in batch biochemical methane potential tests by varying the substrate mixing ratio. Co-digestion with waste activated sludge had an apparent negative effect on both the yield and production rate of methane. Meanwhile, the other co-substrates enhanced the reaction rate while maintaining methane production at a comparable or higher level to that of the mono-digestion of spent coffee ground. The reaction rate increased with the proportion of co-substrates without a significant loss in methanation potential. These results suggest the potential to reduce the reaction time and thus the reactor capacity without compromising methane production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The feasibility of the co-digestion of SCG with various organic wastes was studied. </LI> <LI> FW, <I>Ulva</I>, and whey enhanced the reaction rate without a significant loss in BMP. </LI> <LI> Co-digestion with WAS had an apparent antagonistic effect on methane production. </LI> <LI> The microbial community structure varied little with different substrate mixtures. </LI> </UL> </P>

Acetoclastic methanogenesis led by <i>Methanosarcina</i> in anaerobic co-digestion of fats, oil and grease for enhanced production of methane

Kurade, Mayur B.,Saha, Shouvik,Salama, El-Sayed,Patil, Swapnil M.,Govindwar, Sanjay P.,Jeon, Byong-Hun Elsevier Applied Science 2019 Bioresource Technology Vol. No.

<P><B>Abstract</B></P> <P>Fats, oil and grease (FOG) are energy-dense wastes that substantially increase biomethane recovery. Shifts in the microbial community during anaerobic co-digestion of FOG was assessed to understand relationships between substrate digestion and microbial adaptations. Excessive addition of FOG inhibited the methanogenic activity during initial phase; however, it enhanced the ultimate methane production by 217% compared to the control. The dominance of Proteobacteria was decreased with a simultaneous increase in Firmicutes, Bacteriodetes, Synergistetes and Euryarchaeota during the co-digestion. A significant increase in <I>Syntrophomonas</I> (0.18–11%), <I>Sporanaerobacter</I> (0.14–6%) and <I>Propionispira</I> (0.02–19%) was observed during co-digestion, which substantiated their importance in acetogenesis. Among methanogenic Archaea, the dominance of <I>Methanosaeta</I> (94%) at the beginning of co-digestion was gradually replaced by <I>Methanosarcina</I> (0.52–95%)<I>.</I> The absence/relatively low abundance of syntrophic acetate oxidizers and hydrogenotrophic methanogens, and dominance of acetoclastic methanogens suggested that methane generation during co-digestion of FOG was predominantly conducted through acetoclastic pathway led by <I>Methanosarcina</I>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The addition of fats, oil and grease enhanced ultimate methane production by 217%. </LI> <LI> Firmicutes, Bacteriodetes, Synergistetes and Euryarchaeota were greatly increased. </LI> <LI> Dominance of <I>Methanosaeta</I> was replaced by <I>Methanosarcina</I> at the end of digestion. </LI> <LI> Methane was predominantly generated through acetoclastic pathway by <I>Methanosarcina</I>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

통합 혐기소화액별 폭기처리에 따른 화학적 성분 변화와 무의 발아효과

변지은,이홍주,류종원,황선구,Byeon, Ji-Eun,Lee, Hong-Ju,Ryoo, Jong-Won,Hwang, Sun-Goo 한국작물학회 2020 한국작물학회지 Vol.65 No.4

This study aimed to determine the minimum period of aeration treatment of co-digestate to develop it as liquid fertilizer and the chemical changes that occur in the aerobic liquefying process. The co-digestates were divided into three types depending on their additives: swine slurry anaerobic digestate (SS AD), swine slurry 70% + cow slurry 30% anaerobic digestate (SS + CS AD), and swine slurry 70% + apple pomace 30% anaerobic digestate (SS + AP AD). The pH of all co-digestates increased rapidly after 3 days of aerobic treatment, but had slightly decreased in SS AD after 9 days and in SS + CS AD and SS + AP AD after 15 days. All co-digestates showed a strongly reduced pH between 27 and 36 days of aeration treatment. SS AD had lower pH value, dissolved oxygen (DO), NH₄-N, and NO₃-N content under aerobic conditions than other co-digestates. To assess the fully decomposed liquid fertilizer, a germination test was performed on the undiluted and diluted co-digestate using the liquid fertilizer germination index (LFGI) method. The relative germination ratio, relative root elongation, and germination index of SS AD were higher than those of the others. When the LFGI method was used for the germination test, all co-digestates showed an appropriate germination index of 70 after 60 days of aeration treatment. Thus, we suggest that the minimum period of aeration treatment for co-digestates might be 60 days to develop the fully decomposed liquid fertilizer.

Pilot Scale Solid State Anaerobic Co-digestion of Dairy Manure and Milking Parlor Wastewater

Seunghun Lee,Eunjong Kim,Myeongseong Lee,Jisoo Wi,Heekwon Ahn 한국토양비료학회 2020 한국토양비료학회지 Vol.53 No.2

A pilot scale solid-state anaerobic co-digestion study was conducted to elucidate the feasibility of anaerobic digestion as an effective treatment method for dairy manure (DM) and milking parlor wastewater (MPW), and it focusing mainly on the stability of anaerobic digestion process and methane production potential. Dairy manure and milking parlor wastewater were co-digested (1/0.48, w/w) in 11m3 volume reactor for 63days at the mesophilic condition (36°C). In addition, pH, volatile fatty acids and ammonia were periodically analyzed to monitor anaerobic digestion inhibitions. The results showed that the co-digestion of DM and MPW was successfully performed without any inhibition caused by ammonia and volatile fatty acids accumulation. The potential methane production (P) from a modified Gompertz model was about 130.5 mL g-VS<SUP>-1</SUP>, and approximately 80% of the methane production was obtained during the 40 days digestion test and the lag phase was 14 days. The pilot scale SSAD (solid-state anaerobic digestion) system showed about 1.3-fold higher methane production than lab-scale system. The results of solid-state anaerobic co-digestion of bedded pack barn dairy manure and milking parlor wastewater using pilot-scale anaerobic digester can be used as a reference for the design of farm-scale anaerobic digester.

Co-digestion of untreated macro and microalgal biomass for biohydrogen production: Impact of inoculum augmentation and microbial insights

Sivagurunathan, Periyasamy,Kumar, Gopalakrishnan,Kobayashi, Takuro,Xu, Kaiqin,Kim, Sang-Hyoun,Nguyen, Dinh Duc,Chang, Soon Woong Elsevier 2018 International journal of hydrogen energy Vol.43 No.25

<P><B>Abstract</B></P> <P>This study assessed the co-digestion of macro and microalgal biomass towards the improvement of hydrogen production. The red macroalgal biomass (<I>Gelidium amansii</I>) and green mixed microalgal biomass was mixed in a ratio of 8:2, with an initial substrate concentration of 10 g/L, and various amount of inoculum addition range from 3 to 15% (v/v) was evaluated to assess the feasible substrate to inoculum ratio for the effective co-digestion of the algal biomass. The results showed that the co-digestion with 6% inoculum addition provided the peak hydrogen yield of 45 mL/g dry biomass added with a high hydrogen content of 24% in the gas phase. The other tested conditions showed moderate hydrogen content in the range of 17–22%, respectively. These results suggest that anaerobic co-digestion of macro and microalgal biomass, with appropriate initial biomass loading (6%) is essential for enhanced hydrogen production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Inoculum augmentation improves the co-digestion performances. </LI> <LI> Maximum hydrogen yield of 45 mL H<SUB>2</SUB>/g TS was achieved. </LI> <LI> Peak COD removal efficiency of 28.5% achieved at 6% inoculum loading rate. </LI> <LI> <I>Eubacteria</I> and <I>Clostridium</I> were the dominant microflora. </LI> </UL> </P>

Co-feeding spent coffee grounds in anaerobic food waste digesters: Effects of co-substrate and stabilization strategy

Kim, Danbee,Kim, Hakchan,Kim, Jaai,Lee, Changsoo Elsevier 2019 Bioresource technology Vol.288 No.-

<P><B>Abstract</B></P> <P>Anaerobic digestion of spent coffee grounds (SCG) is considered disadvantageous, particularly under mono-digestion conditions, owing to slow degradation and nutrient imbalance. This study investigated the effect of co-feeding of SCG at a low ratio into food waste (FW) digesters, with the aim to determine whether SCG can be effectively treated and valorized using the spare capacity of existing digesters. Duplicate reactors showed stable performance under FW mono-digestion conditions but manifested severe deterioration in three volume turnovers after co-feeding of SCG (FW:SCG at 10:1 on a volatile solids basis). The reactors failed to recover despite repeated interrupted feeding and stabilization, and <I>Ulva</I> was added (FW:SCG:<I>Ulva</I> at 20:2:1) for nutrient supplementation. The two reactors subjected to different stabilization strategies (i.e., timing and intervals of interrupted feeding) responded differently to <I>Ulva</I> co-feeding: one recovered and maintained stable albeit suboptimal performance, whereas the other failed. Furthermore, the microbial communities developed differently in the reactors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SCG was anaerobically treated as a co-substrate in continuous food waste digesters. </LI> <LI> SCG co-feeding at 10% of food waste (VS basis) led to major process disturbances. </LI> <LI> Stable performance was restored with added <I>Ulva</I> (5% of food waste) in one reactor. </LI> <LI> Stabilization strategies significantly influenced process resilience and stability. </LI> <LI> Both archaeal and bacterial community structures changed greatly after adding SCG. </LI> </UL> </P>

Effect of pretreatment and anaerobic co-digestion of food waste and waste activated sludge on stabilization and methane production

Naran, E.,Toor, U.A.,Kim, D.J. Elsevier Applied Science 2016 International biodeterioration & biodegradation Vol.113 No.-

The effect of pretreatment and anaerobic co-digestion of food waste (FW) and waste activated sludge (WAS) was assessed by the reductions of total suspended solids (TSS), volatile suspended solids (VSS), COD removal and methane production. Thermal treatment and anaerobic digestion reduced VSS up to 43.4% (FW) and 43.1% (FW + WAS) by increasing the solubilization of the feedstock. Methane yields of ultrasonic treatment reached 206.4 (FW) and 326.3 (FW + WAS) mL CH<SUB>4</SUB> g<SUP>-1</SUP> VSS removed which were 50.5 and 56.2% higher than that of the control. Results showed that each pretreatment gave distinctive effect on different feedstocks due to dissimilar composition. Co-digestion conferred superior result than mono digestion with FW or WAS. Estimated parameters (methane production potential and the rate) with Gompertz equation also inferred that co-digestion increased methane production significantly.