• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.6
• /
• pp.407-414
• /
• 2013

Full scale livestock wastewater treatment plant (100 t/d) was constructed and operated to develop compact and cost effective treatment process for public plant as well as individual farm. Liquid form of livestock wastewater after belt press filter was treated through MBR/NF/RO. NF/RO brine water was mixed with livestock wastewater sludge and treated using denitrification, coagulation and air flotation process. Mixed effluent of NF/RO and air flotation meet public livestock wastewater treatment standard, BOD, T-N and T-P, 30 mg/L, 60 mg/L, 8 mg/L below, respectively. Condensed sludge of air flotation returned belt press filter. Dewatered cake contained 90% water and could be used fertilizer after mixing sawdust.

• Korean Journal of Microbiology
• /
• v.35 no.4
• /
• pp.283-288
• /
• 1999

The effect of dissolved oxygen(DO) concentration on the growth of Pseudomonas aeruginosa and it's mutant M-10 was studied the growth kinetics and the possibility of waste treatment for reducing the amount of excess sludge. Different DO concentrations on the growth of wild type Pseudomonas aeruginosa affected to cellular yields, decreasing with increasing DO concentrations. Under these conditions, the maximum 14 folds decrease of cellular yield was achieved at 90 ppm DO levels by screened, being able to reduce their cellular yields under low DO concentration. The optimum mutation conditions were obtained by the treatment of NTG mutagen at 30${\circ}C$ for 1 hr. The growth characteristics of the selected mutant M-10 showed the same as the wild type growth kinetics. However, cellular yields are significantly decreased to 55% compared with those of wild type under DO concentrations increased. We, therefore, expect the application of the mutants to waste treatment for reducing excess sludge.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.4
• /
• pp.515-521
• /
• 2004

Anaerobic digestion has many advantages over the more conventional aerobic treatment processes such as low levels of excess sludge production, low space (area) requirements, and the production of valuable biogas. The purpose of this study was to evaluate the effect of organic loading rate of anaerobic digestion on thermophilic($55^{\circ}C$) and mesophilic($35^{\circ}C$) conditions. Fluorescent in situ hybridization (FISH) method was also used to study the microbial community in the reactors. The stabilizing time in mesophilic anaerobic reactors was shorter as approximately 20 days than 40 days in the thermophilic anaerobic reactors. The amount of methane production rate in anaerobic reactors was independent of the concentrations of supplied substrates and the amount of methanogens. When the microbial diversity in the mesophilic and thermophilic reactors, which had been treated with acetate-based artificial wastewater, were compared, it was found that methanogenesis was carried out by microbial consortia consisting of bacteria and archaea such as methanogens. To investigate the activity of bacterial and archaeal populations in all anaerobic reactors, the amount of acetate was measured. Archaea were predominant in all reactors. Interestingly, Methanothrix-like methanogens appeared in mesophilic anaerobic reactors with high feed substrate concentrations, whereas it was not observed in thermophilic anaerobic reactors.

• Journal of Korea Technology Innovation Society
• /
• v.2 no.2
• /
• pp.290-308
• /
• 1999

In this study a system for the treatment or recyling of organic wastes from both urban and rural area was recommended. It was developed based on the resource recovery system regarding human being by four tectnologies; forage, methane production, high-grade composting and complete decomposition. High quality compost can be produced by combining several kind of wastes produced from urban and agricultural areas. High quality compost must possess not only general characteristics of ordinary compost, but also a superior ability to improve the soil properties and must contain more nutrients for plant. Cedar chips were recommended as the main bulking agent to adjust moisture contents and air permeability. Charcoal and zeolite can be used not only as the second bulking agent but also as fertilizer for improve the soil amendment. Complete decomposition of organic wastes is defined by organic matter being completely converted to $CO_2$ and water. All the input water was evaporated by the heat produced through the oxidation of organic matter, In the present study, the complete treatments were successfully achieved for Shochu wastewater, swine wastes, thickened excess sewage sludge, wastes produced by Chinese restaurant and anaerobic digested sludge. First of all, recycling center of organic wastes should be established for the protect the environments and effective recovery of organic resources. This may means the way to derive the recovery of human value.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.6
• /
• pp.599-606
• /
• 1998

Removal of toluene vapor from airstreams was studied in a biological reactor known as a biofilter. The biofilter was packed porous ceramic inoculated with thickened activated sludge (MLVSS 17,683 mg/L). The lab-scale biofilter was operated for 42 days under various experimental conditions including inlet toluene concentrations and flow rates of the contaminated air streams. Removal efficiency reached up 96.6% after 4 days from start up. Nutrient limitation was proposed as a reason for the decrease in biofilter performence. Biofilter performance decreased substantially, coincident with the buildup of back pressure due to accumulation of excess VSS within the medium bed. Practically, the bed needs to be backwashed when the overall pressure drop is greater than 460.6 Pa at SV (Space Velocity) 100 h-1. Periodic backwashing of the biofilter was necessary for removing excess biomass and attaining stable long -term high removal efficiency The removal efficiency of toluene in the biofilter decreased as the gas velocity and toluene concentration in the inlet gas increased. The maximum elimination capacity of ceramic biofilter could reach up to 444.85 g/m3. hr. When the loading of toluene exceed this critical value, substrate inhibition occurred.

• Journal of Korean Society of Water and Wastewater
• /
• v.8 no.2
• /
• pp.25-34
• /
• 1994

In this research, investigations were made on the effect of type and load of organic substrate on phosphorus release. Reactors of three different sizes were operated, being fed on five kinds of organic substrates. The quantitative analyses were made on phosphorus release and substrate utilization under anaerobic condition. The molar ratios of the uptaken organic substrate to the released phosphorus were 0.5 with acetate, 0.6 with glucose, 0.8 with glucose/acetate, and 1.2 with glucose/acids, respectively. The phosphorus release was inhibited at the higher organic load than the normal at stead state. Both acetate and acids/glucose enhanced phosphorus release- as well as uptake-rate, however, the complete phosphorus removal was achieved after the microbial adaptation to the new environment. In case with acetate, operation was hampered by the poor sludge settleability and phosphorus uptake was not enough although the phosphorus release was active. But with milk/starch, the phosphorus release and uptake was well developed even though phosphorus release was not comparatively high. From this study, it was concluded that organic substrates, such as glucose seemed to be converted fatty acids after fast bio-sorption, followed by concurrent uptake of these acids by excess phosphorus removing bacteria.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.27 no.6
• /
• pp.690-695
• /
• 1994

Simultaneous removal of phosphorus and nitrogen from wastewater was studied by the anaerobic-aerobic system of activated sludge. In the anaerobic stage, most of the influent glucose was removed and orthophosphate was released, when the nitrate and/or nitrite concentration in the wastewater was almost zero. The amount of the released phosphorus was found to be directly proportional to the amount of the removed glucose. When the ratio of phosphorus to glucose in the influent was less than 0.04, the phosphorus in the wastewater was almost completely removed during the aerobic state. Under the anaerobic condition, activated sludge released phosphate and excess removal of phosphate occurred during the aerobic condition. Namely, the stress received in anaerobic period stimulated the uptake of phosphorus in aerobic period. The amounts of phosphorus release in the anaerobic and uptake in the aerobic stage were less in proportional to the concentration of $NO_x-N$. Further, if the initial ratio of $NO_2-N$/glucose was less than 0.37, the inorganic nitrogen in the influent could be completely removed.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.7
• /
• pp.516-522
• /
• 2011

The largest problem of domestic anaerobic digestion is low digestion efficiency. Reasons of the problem would be low organic matters input, low mixing efficiency in digestion tank, refractory excess sludge etc.. In this study, screw attached disk-type concentration system and a mechanical mixing system, solubilization facility improvements were performed to solve problems. Through these improvements, the sludge conc. of the concentrator increased 2.6-fold and the volume reduction efficiency was increased 3.0-fold. In addition, the dead-space is reduced by mechanical agitation. Anaerobic digester gas production in the digestion tank is increased from $193.8m^3$ to $386.0m^3$ per day. Digestion efficiency is improved to 54.6% from 47.6%. Digestion gas production is increased from $0.30Nm^3/kg$ VS to $0.42Nm^3/kg$ VS.

• Resources Recycling
• /
• v.25 no.3
• /
• pp.29-36
• /
• 2016

The characteristics analysis and pH neutralization test were carried out to use of slurry generated from recycling processes of construction wastes. D (5.0) of raw sludge was $42.4{\mu}m$ and over 60 % of sludge distribute under 45 um (-325 mesh). Muscovite and carbonate minerals were main minerals of fine particles, and the portion of carbonate minerals increased as particle size decreased. Although the more heavy metals were observed in the finer particle size, the contents was found to be less than Korean contaminated soil regulation (area 2). The effects of flocculants addition for accelerating solid-liquid separation were negligible because the slurry already contains excess of coagulant added in the waste concrete recycling process. It was difficult to neutralize the sludge supernatant due to high pH (about 12) by adding acids, but the introduction of $CO_2$ decreased the pH to 8.5, The precipitate recovered during $CO_2$ introduction was determined to be $CaCO_3$ with XRD, and it indicates that high pure $CaCO_3$ could be obtained during the process.

• KSBB Journal
• /
• v.19 no.2
• /
• pp.93-97
• /
• 2004

We investigate the effect of enzyme pretreatment using protease, carbohydrase, and lipase on improvement of sludge treatment efficiency by measuring SCOD and TCOD. The enzyme-pretreatment increases SCOD of excess sludge. In addition, the amount of sludge reduction during digestion, in terms of SCOD and TCOD, are enhanced by enzyme-pretreatment. Among pretense, carbohydrase, and lipase, pretense showed the best enhancement of the sludge treatment efficiency. Sludge digestion followed by ozone and enzyme treatments showed more effective sludge treatment when compared with ozone treatment alone. Therefore, we expect that enzyme pretreatment can be used as a useful tool for enhancing the sludge treatment efficiency.