The purposes of this study were to evaluate the removal characteristics of COD, Ni, and P and to derive appropriate operating conditions for the plating wastewater according to NaOCl reaction time and pH operating conditions in the BPC unit process during the plating wastewater treatment process. As a results of evaluating the removal characteristics for raw wastewater by each BPC unit process, the removal efficiencies of COD, Ni and P in BPC 1-1 unit process were 72.8%, 99.1%, and 100.0%. Therefore, the proper reaction time of NaOCl was derived as 21.1 minutes. In order to maintain the +800 mV ORP and the reaction time of 20 minutes, the temporary injection and continuous injection of NaOCl in the BPC unit process were 13.7 mL and 18.7 mL, respectively. It was found that the temporary injection method of NaOCl reduced the chemical cost by 36.5% compared to the continuous injection method. Also, Ni showed the highest removal efficiency of 97.8% at pH 10.5. On the other hand, P showed a removal efficiency of 57.4% at pH 10.0.

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na3PO4, CrO4, 2Na2CrO4 and 2NaNO3 will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane (CH4) from the anaerobic digestion process; and third, to promote CH4 production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), CH4 production, and biodegradability.

The aim in this study was to remove Cl−, which can be problematic in the recycling of bottom ash, by identifying the optimum operating conditions for a soil electrolysis apparatus with spiral paddles and to use these as the base data in removing contaminants from various polluted soils using electrolysis. Unprocessed bottom ash collected from the openair storage yard at thermoelectric power plant H in Gyeong sang nam - do Province was used as the experimental material. The experimental methodology was to identify the optimum operating conditions to remove Cl− contained in the bottom ash using the following variables: use or not of spiral paddles, application or not of electrolysis, change of concentration of the electrolyte solution, electrolysis application time, and the voltage level during electrolysis. From the results, the highest removal efficiency of 91.4% was shown under the following conditions: use of the spiral paddles, use of 0.3% NaOH electrolyte solution, 20 min of electrolysis; and a voltage level of 5 V during electrolysis. It is evident that application of the soil electrolysis apparatus for removal of Cl− from bottom ash could be valuableas base data for purification of polluted soils in the future.

In this study, the International Maritime Organization (IMO)’s guideline MEPC. 277 (64) was developed and evaluated for the removal efficiency of T-N in a SBR and MBR combined process. This combined process of resized equipment based on large capacity water treatment device for a protection of marine aquatic life. In this experiment, T-N concentration of influent and effluent was measured through with the artificial wastewater. The SBR reactor operation time was varied according to the C : N : P ratios so that different conditions for mixing and aeration period in mins (90 : 60, 80 : 40, 70 : 50) and two C: N: P ratios (10 : 5 : 3, 10 : 3 : 1) were used. During experiment in the reactor’s aeration and anoxic tank DO concentrations were 3 mg/L and 0.2 mg/L respectively. Furthermore, in the reactor MLSS concentration was 2000 mg/L and flowrate was 2 L/hr. Experiment results showed that C : N : P, 10 : 3 : 1 ratio with 90 mins mixing and 60 mins aeration maximized removal efficiency at 97.3% T-N as compared to other conditions. The application of the SBR and MBR combined process showed efficient results.

This study aimed to remove organic matter and heavy metals that could affect the recycling of soils contaminated by heavy metals, by means of electrolysis, carried out simultaneously with the leaching of the soil. To ensure better experimental equipment, a soil electrolysis apparatus, equipped with spiral paddles, was used to agitate the heavy-metal-contaminated soil effectively. The heavy-metal-contaminated soil was electrolyzed by varying the voltage to 5 V(Condition 1), 15 V(Condition 2), and 20 V(Condition 3), under the optimal operating conditions of the electrolysis apparatus, as determined through previous studies. The results showed that the pH of the electrolyte solution and the heavy-metal-contaminated soil, after electrolysis, tended to decrease with an increase in voltage. The highest removal efficiencies of TOC and CODCr were 18.8% and 29.1%, 38.8% and 4.2%, and 33.3% and 50.0%, under conditions 1, 2 and 3, respectively. Heavy metals such as Cd and As were not detected in this experiment. The removal efficiencies of Cu, Pb and Cr were 4.7%, 8.3% and 2.1%, respectively, under Condition 1, while they were 42.9%, 15.2% and 22.1%, respectively, under Condition 2, and 4.7%, 23.0%, and 24.9%, respectively, under Condition 3. These results suggest that varying the voltage with the soil electrolysis apparatus for removing contaminants for the recycling of heavy-metal-contaminated soil allows the selective removal of contaminants. Therefore, the results of this study can be valuable as basic data for future studies on soil remediation.

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane (CH4) from the anaerobic digestion process; and third, to promote CH4 production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), CH4 production, and biodegradability.

In response to the water shortage problem, continued attempts are being made to secure consistent and reliable water sources. Among various solutions to this problem, wastewater effluent is an easy way to secure the necessary supply, since its annual output is consistent. Furthermore, wastewater effluent has the advantage of being able to serve various purposes, such as cleaning, sprinkling, landscaping, river management, irrigation, and industrial applications. Therefore, this study presents the possible use of reclaimed industrial wastewater treated with Birm filters and a UF membrane, along with an analysis on membrane fouling. The preprocessing stage, part of the reclamation process, used Birm filters to minimize membrane fouling. Since this study did not consider heavy metal levels in the treated water, the analyses did not include the criterion for irrigation water quality. However, the wastewater reclaimed by using Birm filters and a UF membrane met every other requirement for reclaimed water quality standards. This indicated that the treated water could be used for cleaning, channel flow for maintenance, recreational purposes, and industrial applications. The analysis on the fouling of the Birm filter and UF membrane required the study of the composition and recovery rate of the membrane. According to SEM and EDX analyses of the UF membrane, carbon and oxygen ion composition amounted to approximately 57%, whereas inorganic matter was not detected. Furthermore, the difference in the recovery rates of the distressed membrane between acidic and alkaline cleaning was more than ~78%, which indicated that organic rather than inorganic matter contributed to membrane fouling.

본 연구는 응집제 자동투입장치를 탈수기 전단에 장착하여 농축슬러지의 플록상태에 따른 고분자 응집제 주입량을 다르게 함으로써 탈수케이크의 함수율 저감 및 응집제 사용량 절감, 탈수여액의 수질개선 등 탈수특성에 미치는 영향을 평가하는데 그 목적이 있다. 응집제 자동투입장치를 B시 S하수처리장의 벨트프레스 전단에 적용한 결과 고속회전 및 응집제 분사를 통한 균일한 플록이 형성됨에 따라 기존 시스템 대비 탈수케이크 함수율 및 응집제 주입율 저감효과를 나타내었다. S하수처리장 농축슬러지(TS; Thickened sludge)에 대한 여름철, 가을철 및 겨울철의 기존 시스템 대비 응집제 자동투입장치의 최적 운전조건은 탈수케이크의 함수율 기준으로 판단해 볼 때 각각 DS-P(14%), DS-P(13%) 및 DS-P(12%)로, 이때의 탈수케이크 저감율은 25.3%, 30.7% 및 13.3%를, 고분자 응집제(P; Polymer) 저감율은 17.6%, 16.7% 및 20.0%를 각각 나타내었다. 응집제 자동투입장치의 회전속도와 유입 농축슬러지량 대비 고분자 응집제 주입율과의 상관관계를 평가한 결과 회전속도를 900~1,200 rpm의 범위 내에서 운전시 플록형성이 양호하게 나타났다.

This study aimed to evaluate changes in the TN and TP removal efficiencies, depending on whether or not a settling process is applied, in a sequencing batch reactor (SBR) process with a membrane bioreactor (MBR). Nutrient removal was considered in terms of developing an advanced water treatment system for ships in accordance with water quality standards set forth by 227(64). For these purposes, the TN and TP concentrations in the inflow and outflow water were measured to calculate the TN and TP removal efficiencies, depending on whether or not a settling process was used. Water discharged from a bathroom, which was constructed for the experiment, was used as the raw water. The experiment that included a settling process was conducted twice, and the operating conditions were: aeration for 90 min, settling for 30 min, agitation for 15 min, and settling for 15 min for one experiment; and aeration for 150 min, settling for 45 min, agitation for 15 min, and settling for 15 min in the other. Operating conditions for the experiment that did not include a settling process were: aeration for 180 min and agitation for 60 min. The concentration of the mixed liquor suspended solids (MLSS) in the reactor was 3,500 mg/L, while the aeration rate was 121 L/min and the water production rate was 1.5 L/min. For the two experiments where a settling process was applied, the average TN removal efficiencies were 44.39% and 41.05%, and the average TP removal efficiencies were 47.85% and 46.04%. For the experiment in which a settling process was not applied, the average TN removal efficiency was 65.51%, and the average TP removal efficiency was 52.51%. Although the final nutrient levels did not satisfy the water quality standards of MEPC 227(64), the TN and TP removal efficiencies were higher when a settling process was not applied.

In this study, we have investigated to find optimal pre-treatment flocculation condition by analyzing the floc growth rate with mixing conditions and the membrane permeation flux for pre-treatment step of the membrane process. The higher mixing intensity showed a constant floc size index (FSI) values, and lower mixing intensity increased the degree of dispersion of the FSI values. Results of comparing the distribution characteristics of the FSI value and the permeation flux were more effective in increasing flux when the FSI values were 0.2 or higher. The degree of dispersion of FSI was relatively large in 40 rpm mixing condition compared to 120 rpm. In 40 rpm mixing condition, it decreased the permeation flux compared to 120 rpm because various sizes of flocs were distributed. Coagulation-UF membrane process enhanced 30%∼40% of the flux rate compare to UF alone process, and the coagulation-MF process increased up to 5% of the flux rate compare to MF alone process. Pre-treatment, that is, coagulation process, has been found to be less effects on relatively larger pore size for MF membrane. For UF membrane, the flux was a little bit same when applying only the rapid mixing process or rapid mixing with slow mixing processes together. In case of MF membrane, the flux was improved when rapid mixing process applied with slow mixing process together.

The objective of this study was to make a SBR+MBR complex process to evaluate the possible use of the advanced water treatment system for ships (SBR+MBR complex process) in accordance with the amendments MAPOL 73/78 that went into effect. The conditions 1 and 2 did not show the quick reduction in anaerobic condition while in the precipitation and stirring stages of the SBR treatment which was determined to be ineffective denitrification, same as with the ORP. Removal of organic matters such as BOD5 and CODCr in the SBR treatment was observed to happen smoothly and going through the MBR treatment as well would provide a stable water quality. However, the results were not satisfactory in accordance with BOD5 25 mg/L and CODCr 125 mg/L. Thus, the operating conditions improvement is deemed necessary. Likewise for the nutrients (T-N and T-P), the nitrification in bioreactor, denitrification and phosphorus absorption in aerobic tank due to phosphorus release in anaerobic tank had not been proceeded effectively. It was concluded that the improved operating conditions and structural changes would provide more effective treatments since the removal rates of T-N and T-P were less than 70% and 80%, respectively, which were standards specified by the MEPC. 227(64).

There are two treatment processes that are currently applied to ships are the biological treatment process using the activated sludge and the electrochemical treatment. However, neither of them are able to remove both nitrogen and phosphorus due to their limited ability to remove organic matters, which are main causes of the red tide. This study was conducted to identify the characteristics of nitrogen removal factors from manure wastewater by replacing the final settling tank in SBR (Sequencing Batch Reactor) process and applying immersion type hollow fiber membrane. SBR process is known to have an advantage of the least land requirement in special environment such as in ship and the immersion type hollow fiber membrane is more stable in water quality change. As the result, the average in the cases of DO (Dissolved Oxygen) is 2.9(0. 6∼3.9) mg/L which was determined to be the denitrifying microorganism activity in anaerobic conditions. The average in the cases of ORP (Oxidation Reduction Potential) is 98.4∼237.3 mV which was determined to be the termination of nitrification since the inflection point was formed on the ORP curve due to decrease in the stirring treatment after the aeration, same as in the cases of DO. Little or no variation in the pH was determined to have positive effect on the nitrification. T-N (Total Nitrigen) removal efficiencies of the finally treated water were 71.4%, 72.3% and 66.5% in relatively average figures, thus was not a distinct prominence. In being applied in ships in the future, the operating conditions and structure improvements are deemed necessary since the MEPC (Marine Environment Protection Committee). 227(64) ship sewage nitrogen is less than the standard of 20 Qi/Qe mg/L or the removal rate of 70%.

본 연구는 폐 컴퓨터를 자원회수에 긍정적인 영향을 주고자 폐 컴퓨터(PCB)를 이용한 유가금속회수 공정에서 비중선별에 의한 분리 특성 및 금속함량에 관한 연구를 통해 효과적인 유가금속 회수를 위하는데 그 목적이 있다. 실험재료로 폐 컴퓨터(PCB)를 사용하였으며, PCB리드커터기를 이용해 PCB기판의 부착물 제거 후 고속분쇄기(1차분쇄) 및 미분쇄기(2차분쇄)를 이용하여 일정 크기에 따라 분쇄를 실시하였다. 분쇄물들은 체선별을 통해 입경크기별(n<0.2, 0.2<n<0.5, 0.5<n<1.0, 1.0<n<2.0 및 2.0<n)로 구분하여 중액분리를 실시하였다. 중액분리는 TBE(Tetrabromoethane)를 사용하였다. 5 min, 10 min, 15 min, 20 min 및 30 min의 시간을 주어 시간에 따른 비중선별 정도를 확인하였으며, 중액의 비중변화를 위해 희석액으로 에탄올을 사용해 비중액 비중(1.6, 1.85 및 2.1)을 변화시켜가며 실험을 진행하였다. 전체적인 비중선별 결과 비교시 비중 2.1과 1.85의 결과 값에서 큰 차이가 나타나지 않았으며, 경제적인 면으로 볼 때 비중 1.85가 적합하다고 판단되며, 플라스틱 및 산화물의 함량은 부유물에서 높은 것으로 나타남에 따라 유용금속의 및 기타금속의 함량은 침전물에서 높은 것으로 나타났다.

MEPC. 227(64)가 발의되면서 해상에서 선박 배출수의 오염에 대한 규제가 강화되었다. 특히 T-P에 대하여 유입수 대비 유출수의 제거율을 1.0 mg/L 또는 80%로 제한하고 있다. 이를 충족시키기 위해 SBR+MBR 공정을 적용하여 시험운전을 진행하였으며, 그에 따른 문헌조사 결과 생물학적 처리만으로 인의 목표 처리효율을 충족시키는 것에 한계가 있을 것으로 판단하여 응집제(PAC 5)를 도입하였다. 따라서 본 연구는 PAC 5를 이용한 응집공정 적용시 T-P의 제거율이 어떻게 변화하는지 연구하는 데에 그 목적이 있다. 실험에 사용된 원수는 실험을 위해 자체 제작한 화장실에서 발생된 오수를 사용하였으며 원수의 T-P 농도는 33.215 mg/L로 측정되었다. 실험은 총 3 사이클 동안 진행되었으며, SBR+MBR 공정을 거친 1차 유출수의 T-P 농도 및 제거율의 평균값과 PAC 5를 이용하여 응집공정까지 시행된 2차 유출수의 T-P 농도 및 제거율의 평균값을 비교하였다. 실험 결과 1차 유출수의 평균 T-P 농도는 15.05 mg/L로 유입수 대비 유출수가 70.8%의 제거율로 나타났고, 또한 2차 유출수의 경우 평균 농도 3.47 mg/L로 93.3%의 제거율로 나타났다. 실험을 통해 PAC 5를 적용한 응집공정을 실시하였을 때 T-P 평균 제거율이 22.5%가 상승한 것으로 확인되었다. 따라서 SBR+MBR 공정을 적용한 고도수처리장치에 있어서 PAC 5를 이용한 응집공정 적용은 긍정적인 것으로 판단된다.

본 연구는 음식물류 폐기물 처리장에서 발생하는 부산물의 활성화 공정을 통해 제조된 친환경 활성탄의 공업분석, 요오드 흡착 성능, 메틸렌블루 등의 특성을 평가하고, 그로 인한 탁도 및 색도 제거능력을 연구하여 활성탄의 대체물질로서의 재활용 가능성을 평가하고자 한다. 실험에 사용된 실험재료는 B시 F사의 음식물류 폐기물 처리시설에서 발생하는 음식물류 폐기물 처리장 부산물을 함수율 10% 미만으로 건조한 후, 분쇄기로 100 mesh 이하로 하여 사용하였다. 연구에 사용한 실험 장치는 최고온도 1,200℃까지 유지 가능한 고온전기로를 사용하였고, 600℃ 90분의 친환경 활성탄 시료의 요오드 흡착 성능이 가장 높게 나타났으며, 한국 활성탄소공업협동조합 수처리용 분말활성탄 기준인 950mg/g 이상의 기준과 비교하였을 경우는 600℃ 90분의 975.11mg/g 및 700℃ 60분의 950.92mg/g이 기준에 만족하는 것으로 나타났다. 메틸렌블루 탈색력 역시, 요오드 흡착성능 분석과 마찬가지로 600℃ 90분의 친환경 활성탄 시료의 메틸렌블루 탈색력이 가장 뛰어나게 나타났다. 또한 대부분의 활성화 온도에서의 메틸렌블루 탈색력이 요오드 흡착 성능과 비슷한 양상을 나타냄을 알 수 있었다. 이와 같이, 본 연구에서는 음식물류 폐기물 처리장 부산물을 이용하여 제조된 친환경 활성탄의 활성탄 대체물질로서 재활용이 충분히 가능할 것으로 판단했다.

The main objective of this study is to recovery valuable metals with metal particle size distributions in waste cell phone PCBs(Printed Circuit Boards) by means of pulverization and nitric acid process. The particle size classifier also was evaluated by specific metal contents. The PCBs were pulverized by a fine pulverizer. The particle sizes were classified by 5 different sizes which were PcS1(0.2 mm below), PcS2(0.20~0.51 mm), PcS3(0.51~1.09 mm), PcS4(1.09~2.00 mm) and PcS5(2.00 mm above). Non-magnetic metals in the grinding particles were separated by a hand magnetic. And then, Cu, Co and Ni were separated by 3M nitric acid. Particle diameter of PCBs were 0.388~0.402 mm after the fine pulverizer. The sorting coefficient were 0.403~0.481. The highest metal content in PcS1. And the bigger particle diameter, the lower the valuable metals exist. The recovery rate of the valuable metals increases in smaller particle diameter with same leaching conditions. For further work, it could improve to recovery of the valuable metals effectively by means of individual treatment, multistage leaching and different leaching solvents.

This objectives of research are to figure out combustion characteristics with increasing temperature with petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and sawdust, and to exam heating value and ignition temperature for using refused derived fuels(RDFs). After analyzing TGA/DTG, petrochemical sludge shows a rapid weight reduction by vaporing of inner moisture after 170℃. Gross weight reduction rate, ignition temperature and combustion rates represent 68.6%, 221.9℃ and 54.1%, respectively. In order to assess the validity of the RDFs, the petrochemical sludge by adding wasted organic matters which are waste electric wire, anthracite coal and waste sawdust. The materials are mixed with 7:3(petrochemical sludge : organic matters)(wt%), and it analyzes after below 10% of moisture content. The ignition temperatures and combustion rates of the waste electric wire, anthracite coal and waste sawdust are 410. 6℃, 596.1℃ and 284.1℃, and 85.6%, 30.7% and 88.8% respectively. In heating values, petrochemical sludge is 3,600 kcal/kg. And the heating values of mixed sludge (adding 30% of the waste electric wire, anthracite coal and waste sawdust) each increase up to 4,600 kcal/kg, 4,100 kcal/kg and 4,300 kcal/kg. It improves the ignition temperatures and combustion rates by mixing petrochemical sludge and organic matters. It is considered that the production of RDFs is sufficiently possible by using of petrochemical sludge by mixing wasted organic matters.

본 연구는 하수슬러지의 플록상태를 파악할 수 있는 응집제 자동투입장치를 탈수기 전단에 장착하여 하수슬러지(소화슬러지, 농축슬러지) 플록상태에 따른 고분자 응집제 주입량을 다르게 함으로써 탈수케이크의 함수율 저감 및 응집제 사용량 절감, 탈수여액의 수질개선 등을 평가하는데 그 목적이 있다. 응집제 자동투입장치를 B시 N하수처리장 소화슬러지 및 S하수처리장 농축슬러지에 적용한 결과 고속회전 및 응집제 분사를 통한 균일한 플록이 형성됨에 따라 탈수케이크 함수율 및 응집제 주입율 저감효과를 나타내었다. 하수슬러지의 탈수실험 결과 소화슬러지에 대한 고분자 응집제의 적정주입율은 12%로 나타났으며, 이때의 비저항계수(SRF)는 1.11×1011 m/kg으로 나타났다. 또한, 농축슬러지에 대한 고분자 응집제의 적정주입율은 16%로 나타났으며, 이때의 비저항계수(SRF)는 1.68×1011 m/kg으로 나타났다. 또한 응집제 자동투입장치의 회전속도와 유입 하수슬러지량 대비 고분자 응집제 주입율과의 상관관계를 평가한 결과 회전속도를 900~1,200 rpm의 범위 내에서 운전시 플록형성이 양호하게 나타났다. 기존 시스템 대비 응집제 자동투입장치의 경제성 평가 결과 N하수처리장 및 S하수처리장의 경우 각각 연간 263,542,490원 및 42,174,700원으로 산출되었으며, 시설투자비 회수기간은 각각 2.3년 및 7.1년으로 나타났다. 따라서, 하수처리장 탈수기 전단에 응집제 자동투입장치를 적용함으로써 함수율 및 약품주입량 저감 뿐만 아니라 중앙제어실을 통한 실시간 모니터링이 가능하므로 인력감축 유도 및 공정자동화에도 기여할 수 있을 것으로 판단된다.