Young-Man Yoon

Potential of anaerobic digestion for material recovery and energy production in waste biomass from a poultry slaughterhouse.

This study was carried out to assess the material and energy recovery by organic solid wastes generated from a poultry slaughterhouse. In a poultry slaughterhouse involving the slaughtering of 100,000 heads per day, poultry manure & feather from the mooring stage, blood from the bleeding stage, intestine residue from the evisceration stage, and sludge cake from the wastewater treatment plant were discharged at a unit of 0.24, 4.6, 22.8, and 2.2 Mg day(-1), consecutively. The amount of nitrogen obtained from the poultry slaughterhouse was 22.36 kg 1000 head(-1), phosphate and potash were 0.194 kg 1000 head(-1) and 0.459 kg 1000 head(-1), respectively. As regards nitrogen recovery, the bleeding and evisceration stages accounted for 28.0% and 65.8% of the total amount of recovered nitrogen. Energy recovered from the poultry slaughterhouse was 35.4 Nm(3) 1000 head(-1) as CH4. Moreover, evisceration and wastewater treatment stage occupied 88.1% and 7.2% of the total recovered CH4 amount, respectively.

Effects of substrate to inoculum ratio on the biochemical methane potential of piggery slaughterhouse wastes.

The aim of this study was to assess the effect of substrate to inoculum ratio (S/I ratio) on the biochemical methane potential (BMP) and anaerobic biodegradability (Ddeg) of different piggery slaughterhouse wastes, such as piggery blood, intestine residue, and digestive tract content. These wastes were sampled from a piggery slaughterhouse located in Kimje, South Korea. Cumulative methane production curves for the wastes were obtained from the anaerobic batch fermentation having different S/I ratios of 0.1, 0.5, 1.0, and 1.5. BMP and anaerobic biodegradabilities (Ddeg) of the wastes were calculated from cumulative methane production data for the tested conditions. At the lowest S/I ration of 0.1, BMPs of piggery blood, intestine residue, and digestive tract content were determined to be 0.799, 0.848, and 1.076 Nm3 kg−1-VSadded, respectively, which were above the theoretical methane potentials of 0.539, 0.644, and 0.517 Nm3 kg−1-VSadded for blood, intestine residue, and digestive tract content, respectively. However, BMPs obtained from the higher S/I ratios of 0.5, 1.0, and 1.5 were within the theoretical range for all three types of waste and were not significantly different for the different S/I ratios tested. Anaerobic biodegradabilities calculated from BMP data showed a similar tendency. These results imply that, for BMP assay in an anaerobic reactor, the S/I ratio of anaerobic reactor should be above 0.1 and the inoculum should be sufficiently stabilized to avoid further degradation during the assay.

Biochemical Methane Potential of Agricultural Waste Biomass

Recently, anaerobic methane production of agricultural waste biomass has received increasing attention. Until now domestic BMP (Biochemical methane potential) studies concerned with agricultural waste biomass have concentrated on the several waste biomass such as livestock manure, food waste, and sewage sludge from WWTP (Waste water treatment plant). Especially, the lack of standardization study of BMP assay method has caused the confused comprehension and interpretation in the comparison of BMP results from various researchers. Germany and USA had established the standard methods, VDI 4630 and ASTM E2170-01, for the analysis of BMP and anaerobic organic degradation, respectively. In this review, BMP was defined in the aspect of organic material represented as COD (Chemical oxygen demand) and VS (Volatile solid), and the influence of several parameters on the methane potential of the feedstock was presented. In the investigation of domestic BMP case studies, BMP results of 18 biomass species generating from agriculture and agro-industry were presented. And BMP results of crop species reported from foreign case studies were presented according to the classification system of crops such as food crop, vegetables, oil seed and specialty crop, orchards, and fodder and energy crop. This review emphasizes the urgent need for characterizing the innumerable kind of biomass by their capability on methane production. Key words:

Isolation and Characterization of a New Methanobacterium formicicum KOR-1 from an Anaerobic Digester Using Pig Slurry.

A new methanogen was isolated from an anaerobic digester using pig slurry in South Korea. Only one strain, designated KOR-1, was characterized in detail. Cells of KOR-1 were straight or crooked rods, non-motile, 5 to 15 μm long and 0.7 μm wide. They stained Gram-positive and produced methane from H2+CO2 and formate. Strain KOR-1 grew optimally at 38°C. The optimum pH for growth was 7.0. The strain grew at 0.5% to 3.0% NaCl, with optimum growth at 2.5% NaCl. The G+C content of genomic DNA of strain KOR-1 was 41 mol%. The strain tolerated ampicillin, penicillin G, kanamycin and streptomycin but tetracycline inhibited cell growth. A large fragment of the 16S rRNA gene (~1,350 bp) was obtained from the isolate and sequenced. Comparison of 16S rRNA genes revealed that strain KOR–1 is related to Methanobacterium formicicum (98%, sequence similarity), Methanobacterium bryantii (95%) and Methanobacterium ivanovii (93%). Phylogenetic analysis of the deduced mcrA gene sequences confirmed the closest relative as based on mcrA gene sequence analysis was Methanobacterium formicicum strain (97% nucleic acid sequence identity). On the basis of physiological and phylogenetic characteristics, strain KOR-1 is proposed as a new strain within the genus Methanobacterium, Methanobacterium formicicum KOR-1.

Effect of Substrate to Inoculum Ratio on Biochemical Methane Potential in the Thermal Pretreatment of Piggery Sludge

This study was carried out to investigate the effect of substrate to inoculum ratio on ultimate methane potential () from piggery wastes. BMP(Biochemical methane potential) assays were executed for the three samples that have different organic characteristics (Filtrate of pig slurry, LF; Thermal hydrolysate of piggery sludge cake, TH; Mixture of LF and TH at the ratio of 4 to 1, Mix), and values obtained from BMP assays were compared with the theoretical methane potential () of each samples. While values (0.27, 0.44, and ) of TH sample that was pretreated with thermal hydrolysis were below the at all S/I ratios (0.1, 0.3, and 0.5), and values of LF (0.64 and for the S/I ratios of 0.1 and 0.3, respectively) at the lower S/I ratios of 0.1 and 0.3 exceeded the values (). And also biodegradability () of LF sample were obtained as 152.07%, 122.67%, and 95.71% at the S/I ratios of 0.1, 0.3, and 0.5, respectively, and unreasonable values were presented at lower S/I ratios of 0.1 and 0.3. and of Mix sample showed a similar tendency with those of LF sample. Therefore, TH sample by thermal hydrolysis pretreatment showed lower anaerobic biodegradability than those of other samples (LF and Mix) and ultimate methane potentials of LF and Mix samples were overestimated in the lower S/I ratio of 0.1 and 0.3.

The Performance of Anaerobic Co-digester of Swine Slurry and Food Waste

In order to assess the performance of co-digester using pig slurry and food waste at the farm scale biogas production facility, the anaerobic facility that adopts the one-stage CSTR of 5 m 3 day -1 input scale was designed and installed under the conditions of the OLR of 2.33 kg m -3 day -1 and HRT of 30 days in an pig farmhouse. Several operation parameters were monitored for assessment of the process performance. The anaerobic facility was operated in three stages to compare the performance of the anaerobic co-digester. In the Stage I, that was fed with a mix of pig slurry to food waste ratio of 7:3 in the input volume, where input TS content was 4.7 (± 0.8) %, and OLR was 0.837-1.668 kg-VS m -3 day -1 . An average biogas yield observed was 252 Nm 3 day -1 with methane content 67.9%. This facility was capable of producing an electricity of 626 kWh day -1 and a heat recovery of 689 Mcal day -1 . In Stage II, that was fed with a mixture of pig slurry and food waste at the ratio of 6:4 in the input volume, where input TS content was 6.9 (± 1.9) %, and OLR was 1.220-3.524 kg-VS m -3 day -1 . The TS content of digestate was increased to 3.0 (± 0.3) %. In Stage III, that was fed with only pig slurry, input TS content was 3.6 (± 2.0) %, and OLR was 0.182-2.187 kg-VS m -3 day -1 . In stage III, TS and volatile solid contents in the input pig slurry were highly variable, and input VFAs and alkalinity values that affect the performance of anaerobic digester were also more variable and sensitive to the variation of input organic loading during the digester operation. The biogas produced in the stage III, ranged from 11.3 to 170.0 m 3 day -1 , which was lower than 222.5-330.2 m 3 day -1 produced in the stage II.

Effect of hydrothermal pre-treatment (HTP) on poultry slaughterhouse waste (PSW) sludge for the enhancement of the solubilization, physical properties, and biogas production through anaerobic digestion

This study is an assessment of the hydrothermal pre-treatment (HTP) of poultry slaughterhouse waste (PSW) sludge for the enhancement of the solubilization, physical properties, and biogas production through anaerobic digestion. This assessment was carried out to ascertain the optimal HTP temperature. The solubilization and physical properties efficacy was investigated by capillary suction time (CST), time to filter (TTF), and particle size. In addition, the anaerobic digestion was investigated through biochemical methane potential (BMP) tests and subsequent statistical analysis using the modified Gompertz model. HTP was found to have improved the solubilization of the PSW sludge with increasing HTP temperature. In addition, the results of the CST, TTF, and particle size decreased with increasing HTP temperature. These results of the assessment that was conducted in this study confirm that the HTP process indeed modifies the physical properties of PSWs to enhance the solubilization of organic solids. Nevertheless, the results of the BMP tests and the modified Gompertz model analysis show that the optimal HTP temperature of PSWs for anaerobic digestion is 190°C. These findings show that to achieve high conversion efficiency, an accurately designed pre-treatment step must be included in the overall anaerobic digestion process for wastewater treatment.

Effects of Residual Hypochlorite Ion on Methane Production during the Initial Anaerobic Digestion Stage of Pig Slurry

The hypochlorite ion (OCl−) is a widely used disinfecting agent in pig rearing in Korea, but its residual effect on CH4 production from pig slurry is unclear. The objective of this study was to investigate the inhibition effects of residual OCl− on CH4 production during the initial anaerobic digestion stage of pig slurry. Three organic concentrations (9.9, 26.2 and 43.7 g/L) of volatile solids (VS) were tested with the addition of 52.3 mg/L OCl−, ten times of the typical concentration used in Korea, or without OCl− (Control) in anaerobic batch culture. The culture was run under mesophilic (38°C) conditions for 20 d. At the lowest organic concentration with OCl−, the VS degradation was 10.3% lower (p<0.05) than Control, while at the higher organic concentration with OCl−, it did not differ from Control. CH4 yields were higher in the control treatments than their OCl− counterpart cultures, and CH4 yields of Control and OCl− treatments at the organic concentrations of 9.9, 26.2 and 43.7 g/L differed in the probability level (p) of 0.31, 0.04, and 0.06, respectively. Additionally, CH4 concentration increased steeply and reached 70.0% within 4 d in the absence OCl−, but a gradual increase up to 60.0% was observed in 6 d in the OCl− treated cultures. The Rm (the maximum specific CH4 production rate) and λ (lag phase time) of 9.9 g/L with OCl− were 8.1 ml/d and 25.6 d, while the Rm was increased to 15.1 ml/d, and λ was reduced to 11.4 d in PS-III (higher organic concentration) with OCl−. The results suggest that a prolonged fermentation time was necessary for the methanogens to overcome the initial OCl− inhibitory effect, and an anaerobic reactor operated with high organic loadings was more advantageous to mitigate the inhibitory effect of residual hypochlorite ion.

Bioenergy and Material Production Potential by Life Cycle Assessment in Swine Waste Biomass

As a result of the growing livestock industry, varieties of organic solid and waste biomass are be generated in swine breeding and slaughtering stages. Anaerobic digestion is a promising alternative for the treatment of livestock waste biomass, as well as for the material recovery and energy production. Objectives of this study were to analyze the biochemical methane potential of swine waste biomasses that were generated from swine pen and slaughterhouse and to investigate the material recovery and methane yield per head. As pig waste biomass, swine slurry, blood, intestine residue, and digestive tract content were collected for investigation from pig farmhouse and slaughterhouse. The (Theoretical methane potential) and (Biochemical methane potential) of swine slurry generating in swine breeding stage were 0.525 and , the ratio of degradation () was 68.6%. of blood, intestine residue, and digestive tract content were 0.539, 0.664, and , and were 0.405, 0.213, and , respectively. And the ratio of degradation showed 75.1, 32.1, and 46.4% in blood, intestine residue, and digestive tract content. Material yield of swine waste biomass was calculated as TS 73.79, VS 46.75, TN 5.58, 1.94, and . And methane yield was . In the aspect that slaughterhouse is a large point source of waste biomass, while swine farmhouse is non-point source, the feasibility of an anaerobic digestion using the slaughtering waste biomass need to be assessed in the economical aspect between the waste treatment cost and the profitable effect by methane production.

Correction Method of Anaerobic Organic Biodegradability by Batch Anaerobic Digestion

This research was carried out to develop the correction method of VDI4630 method improving accuracy, and investigated the effects of carbonate ion () and reactant water () on anaerobic organic biodegradability in VDI4630 method. Pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were experimented as waste biomasses. Chemical formulas of pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content were , , , , respectively. And amount of reactant moisture for the anaerobic degradation of organic materials were 0.336, 0.485, 0.227, 0.266 mol, respectively. In pig blood, pig intestine residue, pig digestive tract content, and cattle rumen content, anaerobic organic biodegradability presented as were 82.3, 81.5, 70.8, and 66.1%, and anaerobic organic biodegradability (AB) by VDI4630 method were 72.2, 87.8, 74.2, 62.0%, and that were significantly different with anaerobic organic biodegradability presented as . The effects of carbonate ion and reactant water on anaerobic organic biodegradability were not significant, But Accuracy of anaerobic organic degradability was expected to able to be improved by the correction method of VDI4630 considering the carbonate ion at digestate and the reactant water quantified.