• Journal of Korean Society on Water Environment
• /
• v.38 no.2
• /
• pp.95-102
• /
• 2022

Studies for improving the efficiency of the traditional anaerobic digestion process are being actively conducted. To improve anaerobic digestion efficiency, this study tried to derive the optimal pretreatment conditions and mixing conditions by integrating the heat solubilization pretreatment of sewage sludge, livestock manure, and food waste. The soluble chemical oxygen demand (SCOD) increase rate of sewage sludge before and after heat solubilization pretreatment showed an increased rate of 224.7% compared to the control group at 170℃ and 25 min and showed the most stable increase rate. As a result of the biomethane potential test of sewage sludge before and after heat solubilization pretreatment, the total chemical oxygen demand (TCOD) and SCOD removal rates increased as the heat solubilization temperature increased, but did not increase further at temperatures above 170℃. In the case of methane generation, there was no significant change in the cumulative methane generation from 0.134 to 0.203 Sm³-CH₄/kg-COD at 170℃ for 15 min. As a result of the integrated digestion of organic waste, the experimental condition in which 25% of the sewage sludge, 50% of the food waste, and 25% of the livestock manure were mixed showed the highest methane production of 0.3015 m³-CH₄/kg-COD, confirming that it was the optimal mixing ratio condition. In addition, under experimental conditions mixed with all three substrates, M4 conditions mixed with 25% sewage sludge, 50% food waste, and 25% livestock manure showed the highest methane generation at 0.2692 Sm³-CH₄/kg-COD.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.2
• /
• pp.294-301
• /
• 2017

In this study, we found the optimal manufacturing conditions of livestock manure sludge RDF with the oil-drying method. We performed oil evaporation, oil drying and pelletizing of the sludge to evaluate the value of the product (sludge RDF), and measured the performance of the product using calorimeter and PXRF equipment. Also, we conducted the calorie comparison test between sludge RDF manufactured in this study and wood RDF generally used in the field. Experimental results showed that 30g of the sludge treated by vegetable oil at $130^{\circ}C$ for 25 minutes were the optimal conditions to make the sludge RDF (considering the aspects of eco-friendly and mass production). The caloric value of the sludge RDF manufactured in this study was 5211kcal/kg which is higher than that of wood RDF used widely in the market. Finally, PXRF results showed sludge RDF contains no heavy metals with the exception of sulfur. Therefore, we recommend more study about the sulfur control process for future development of the industrial manufacturing process.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.7
• /
• pp.1128-1133
• /
• 2010

The diversity and abundance of ammonia-oxidizing bacteria (AOB) in activated sludge were compared using PCR-DGGE and real-time PCR assays. Activated sludge samples were collected from five different types of wastewater treatment plants (WWTPs) mainly treating textile, paper, food, and livestock wastewater or domestic sewage. The composition of total bacteria determined by PCR-DGGE was highly diverse between the samples, whereas the community of AOB was similar across all the investigated activated sludge. Total bacterial numbers and AOB numbers in the aerated mixed liquor were in the range of $1.8{\times}10^{10}$ to $3.8{\times}10^{12}$ and $1.7{\times}10^6$ to $2.7{\times}10^{10}$ copies/l, respectively. Activated sludge from livestock, textile, and sewage treating WWTPs contained relatively high amoA gene copies (more than $10^5$ copies/l), whereas activated sludge from food and paper WWTPs revealed a low number of the amoA gene (less than $10^3$ copies/l). The value of the amoA gene copy effectively showed the difference in composition of bacteria in different activated sludge samples and this was better than the measurement with the AOB 16S rRNA or total 16S rRNA gene. These results suggest that the quantification of the amoA gene can help monitor AOB and ammonia oxidation in WWTPs.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.58 no.4
• /
• pp.526-531
• /
• 2009

This paper suggests the dehydration and RDF(Refuse Derived Fuel) production of organic sludge, livestock manure and sewerage sludge causing environmental problems, with hydrothermal pre-treatment process. The renewable technology from the organic wastes must involve short treatment time required, reusable energy source, anti-odor and viruses, low cost for the treatment, and well-fertilization. The hydrothermal pre-treatment process promotes to evaporate moisture in the sludge after being shortly treated in a reactor, which is supplied steam and heat by an external boiler, due to the pressure with steam breaks the cell walls of the sludge, so this process removes the internal moisture of the cell. Then, the treated sludge(solid-state) is mixed with waste vinyls called RDF(6,706kcal/kg).

• Ocean Science Journal
• /
• v.40 no.2
• /
• pp.91-100
• /
• 2005

Bioassay using the marine bacteria, Vibrio fischeri and rotifer, Brachionus plicatilis, and chemical analyses were conducted to assess the toxicity of the various sewage sludges, one of the major ocean dumped materials in the Yellow Sea of Korea. Sludge elutriates extracted by filtered seawater were used to estimate the ecotoxicity of the sludge. Chemical characterization included the analyses of organic contents, heavy metals, and persistent organic pollutants in sludge. Bacterial bioluminescent inhibition (15 min), rotifer mortality (24 hr) and rotifer population growth inhibition (48 hr) assay were conducted to estimate the sludge toxicity. EC50 15 min (inhibition concentration of bioluminescence after 15 minutes exposed) values by Microtox(R) bioassay clearly revealed different toxicity levels depending on the sludge sources. Highest toxicity for the bacteria was found with the sludge extract from dyeing waste and followed by industrial waste, livestock waste, and leather processing waste. Clear toxic effects on the bacteria were not found in the sludge extract from filtration bed sludge and rural sewage sludge. Consistent with Microtox(R) results, rotifer neonate mortality and population growth inhibition test also showed highest toxicity in dyeing waste and low in filtration bed and rural sewage sludge. High concentrations of persistent organic pollutants (POPs) and heavy metals were measured in the samples from the industrial wastes, leather processing plant waste sludge, and urban sewage sludge. However, there was no significant correlation between pollutant concentration levels and the toxicity values of the sludge. This suggests that the ecotoxicity in addition to the chemical analyses of various sludge samples must be estimated before release of potential harmful waste in the natural environment as part of an ecological risk assessment.

• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.895-904
• /
• 2006

The improved MLE (modified Ludzack-Ettinger) process was operated for piggery waste treatment in full-scale public livestock waste treatment plant. The treated waste from bioreactor was suitable for the strict effluent standard of 200 mgCOD/L and 60 mgTN/L as it was dewatered chemically without settling tank and passed through filtration process. Though this treatment method produced a great deal of sludge ($6.4m^3\;per\;m^3$ dewatered piggery waste) it was able to accomplish predominant effluent quality by removing non-biodegradable COD and color without advanced oxidation process as ozone, fenton and etc.. The nitrogen removal efficiency of bioreactor was rapidly declined from March to May (from 0.016 to 0.005 kgN/kgVSS-day) when disinfection is in earnest as well as from warm season when reactor temperature rises higher than $35^{\circ}C$(from 0.016 to 0.008 kgN/kgVSS-day). This study proves that counterplanes for infection residuals, bioreactor temperature and dewatering sludge reduction are necessary for piggery waste treatment.

• Journal of Korean Society on Water Environment
• /
• v.22 no.2
• /
• pp.300-307
• /
• 2006

The combined SHARON (Single reactor system for High ammonium Removal Over Nitrite)-ANAMMOX (Anaerobic ammonium oxidation) reactor were operated in mesophilic condition ($35^{\circ}C$). In this study, microbial granulation and characteristics of SHARON and ANAMMOX sludges were investigated using settling test, Scanning Electron Microscopy (SEM) and Fluorescence In Situ Hybridization (FISH). In SHARON reactor, Aerobic granulation with diameter of 1.5~2.5 mm was accomplished but aerobic granulation was weaker than anaerobic granular sludge. Initial seed sludge of ANAMMOX reactor was used as attached media for biofilm growth. ANAMMOX sludge was more compact and rounder rather than seed sludge. Though ANAMMOX sludge has high activity, it has lower settling ability than the seed granule. The color of ANAMMOX sludge was changed from dark to redish brown granular with diameter of 1~2 mm. In FISH of ANAMMOX sludge, high fraction of Candidatus B. stuttgartiensis which paid great role of nitrogen conversion was detected. Also, FISH results reveals that ANAMMOX bacteria inhabit at inner parts near surface, having advantages in utilization of substrates and protection from oxygen inhibition.

• Journal of Korean Society on Water Environment
• /
• v.22 no.2
• /
• pp.308-313
• /
• 2006

Charicteristics of piggery waste and treatment processing sludges for reuse were investigated. If it was thoroughly regulated in disinfectants, antibiotic substances and heavy metals, raw piggery waste can be gratified in criteria for fermentative compost (liquid) for flowers cultivation. Also, Because it is satisfied with various criteria of heavy metals and fertilizer contents for reuse except water content, primary pre-treatment sludge is very good material for composting. If provated goods on heavy metals are used in coagulation & dewatering process, coagulation & dewatering sludges are suitable for criteria of special waste regulation and by-product compost. This study proves that, if they are accomplished with suitable composting and mature process, piggery waste and processing sludges are free from microbiological problems as well as criteria of composting.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.1
• /
• pp.115-121
• /
• 2012

This study was performed to assess the possibility of application of sewage sludge which is the side-product from domestic sewage treatment plant to the materials for biodiesels by investigating the yields and composition of the lipids and fatty acid methyl esters(FAMEs) from soxhlet extraction and in-situ transesterification. As the results, yields of in-situ transesterification were higher than soxhlet extraction. In comparison by sewage sludge type, yields of sewage sludge mixed nightsoil or livestock were higher than a single sewage sludge. And maximum yield showed up to 14 wt%. Fatty acid composition of extracted lipids and synthesized FAMEs consists of palmitic acid(C16:0), palmitoleic acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), and linoleic acid(C18:2).

• The Journal of the Korea Contents Association
• /
• v.20 no.8
• /
• pp.674-684
• /
• 2020

To investigate the differences of bacterial- and archaeal communities depending on kind of wastewater (municipal/livestock) and on treating conditions of basins, sludges were sampled from 10 basins of 3 municipal wastewater treatment plants(WWTP) with A2O and a activated sludge sample from a livestock WWTP. The metagenomic DNAs of the sludge samples were extracted and amplified with primers, 27F/518R for bacteria and Arch519F/A958R for archaea, and pyrosequenced with Roche 454 GS-FLX Titanium. As results, the bacterial communities in basins of municipal WWTPs were quite different from those of livestock WWTP, but within the same municipal WWTP their community structures were similar to each other regardless of different environmental conditions such as O₂. And their archaeal communities resulted from anaerobic·anoxic basins were clustered only within communities originated from the same WWTP. Furthermore Seo-bu WWTP with high bacterial diversity and species richness performed better N/P-removal compared to the orther WWTPs.