KR20150112151A - System for sludge integrated management of several wastewater treatment plants using environmental impact assessment and the method - Google Patents

Abstract

The present invention relates to an integrated sludge management system for a plurality of sewage treatment plants using an environmental impact assessment and a method thereof and, more particularly, to an integrated sludge management system for a plurality of sewage treatment plants using an environmental impact assessment and a method thereof, capable of reducing the whole environmental load of the sewage treatment plants. According to the embodiment of the present invention, provided is the integrated sludge management system for the sewage treatment plants using the environmental impact assessment which includes a data call unit which calls data required for the integrated sludge management of the sewage treatment plant from a database, an individual environmental impact evaluating unit which evaluates the environmental impact for the individual sewage treatment plant, and an integrated alternative suggesting unit which integrally manages the sludge.

Description

Technical Field [0001] The present invention relates to a sludge integrated management system for a plurality of wastewater treatment plants using environmental impact assessment,

The present invention relates to a sludge integrated management system and method for a plurality of sewage treatment facilities using environmental impact assessment. In more detail, environmental impact assessment for individual sewage treatment facilities is conducted on data related to environmental impacts such as operational data of individual sewage treatment facilities, power generation, drug production, and transportation process, The results of the quantitative environmental impact indicators such as eutrophication, global warming, human toxicity, and acidification, which are generated in the sewage treatment facilities, are derived, and alternatives for managing the sludge to a large number of sewage treatment facilities are derived according to the results, A sludge integrated management system and its method for a large number of sewage treatment plants using environmental impact assessment that can reduce the total environmental burden of a large number of sewage treatment facilities occurring in the zone by suggesting the most suitable management alternative to the treatment facility will be.

Over the past five decades, environmental impact assessment (EIA) has been applied to identify environmental impacts in advance and to review, analyze and evaluate proposed actions to minimize environmental degradation and maximize the potential for sustainable development. Until now, studies on environmental impact assessment tools for such prediction and evaluation have been conducted continuously and have been carried out in many fields.

Wastewater treatment facilities send sewage generated by each zone to each sewage treatment facility and treat it to meet legal water quality standards and discharge it to rivers or shore, making a great contribution to human environment of discharged water system. However, the use of electricity and chemicals for sewage treatment, the generation of large amounts of sludge, and the final disposal process are subject to environmental impacts such as resource consumption, global warming, and human toxicity, An integrated sewerage management system for each area is proposed that integrates and manages several sewage treatment plants.

In addition, each sewage treatment facility relies on various sewage treatment processes and sludge disposal methods, and there are various kinds of drugs used. In particular, in the sludge treatment process, surplus sludge is recycled and used as energy to create digestion gas. However, there are various methods such as transporting to landfill after dehydration and composting or incineration treatment. Therefore, it is difficult to quantitatively evaluate the environmental impacts of the operation processes of many sewage treatment facilities and make practical comparison and analysis of many sewage treatment facilities.

Recently, there are several methodologies for comparing sewage treatment facilities from sludge treatment efficiency, energy consumption, environmental impact, etc. when operating the sewage treatment facility. In the initial studies, most of the comparisons were made with qualitative results, but in recent years, various techniques have been implemented to provide useful information from quantitative data.

However, these technologies can be used to design an improvement plan for the unit process with the highest potential impact from the environmental impact assessment result for the individual sewage treatment facility, or to implement the environmental impact assessment for each individual sewage treatment facility, . The results of this study are summarized as follows: (1) In the case of sewage treatment facilities,

In addition, when designing the improvement plan for the treatment facility with the highest potential for environmental impact after implementing the environmental impact assessment for the operation process of the sewage treatment facility, if the individual sewage treatment facility is considered alone, If you want to replace it, you need a lot of new investment, so it is hard to accept it as an alternative when considering the environmental impact only. In addition, even if there is investment in a new operation facility, the driver's skill in the new operating environment is insufficient, which causes a problem that can affect stable water quality at the beginning of operation of the sewage treatment facility.

Therefore, it is urgent to develop appropriate methods for integrated management of sludge in a large number of sewage treatment facilities in the present area, by recognizing the potential environmental impacts generated in the sludge disposal process of existing individual sewage treatment facilities and the economic benefits generated from the sludge It is a situation.

Korean Patent Publication No. 10-2014-0031754

The present invention has been devised in order to solve such problems, and it is an object of the present invention to provide an environmental impact assessment for individual sewage treatment facilities, including data related to environmental effects such as operation data of individual sewage treatment facilities, power generation, Quantitative environmental impact indicators such as eutrophication, global warming, human toxicity and acidification occurring in the operation process of the sewage treatment facility can be derived and the sludge can be integratedly managed in a plurality of sewage treatment facilities according to the result And a plurality of sewage treatment facilities using the environmental impact assessment that can reduce the total environmental load of a plurality of sewage treatment facilities generated in the sphere by suggesting the most suitable management alternatives among the sewage treatment facilities, An integrated management system and a method thereof.

According to the present invention, it is possible to obtain a sewage treatment facility from a database storing process operation data and various data including aeration amount of sewage treatment facility, sludge waste amount, sludge return amount, drug injection amount, power consumption amount, sedimentation ability, A data calling unit for calling data necessary for sludge unified management of the sludge; Eco-efficiency, acidification, and human toxicity by classifying data that are related to environmental impact by applying environmental impact assessment techniques to the called data, and characterizing the classified data using characteristic factors according to environmental impact categories. An individual environmental impact assessment unit that evaluates the environmental impacts of the individual sewage treatment facilities by deriving the environmental impact indicators of the individual sewage treatment facilities involved; And an integrated alternative presentation unit for integrating and managing sludge for a plurality of sewage treatment facilities by presenting a slip treatment alternative with the least environmental impact based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment unit; The present invention provides a sludge integrated management system for a plurality of sewage treatment facilities using an environmental impact assessment.

Meanwhile, the data calling unit automatically calls up important data related to the environmental impact of the sewage treatment facility among all the data stored in the database, which is separately operated in the individual sewage treatment facility.

On the other hand, the main data that are related to the environmental impact on the sewage treatment facility include at least one of a power amount, a chemical amount, a discharged water quality, a bioreactor, a CO ₂ and NO ₂ emission amount of the digester, and a dehydrated cake amount .

The individual environmental impact assessment unit may include a data classifier for classifying data, which are related to environmental impact, into environmental impact categories by applying environmental impact assessment techniques to the called data, A data characterization unit for characterizing the classified data by multiplying the characteristic factors of the environmental characteristics of the environment by the characteristic factors of the environmental characteristics of the environment, And the like.

On the other hand, the integrated alternative presentation unit may include an alternative derivation unit for deriving various alternatives that can minimize environmental impacts on a plurality of sewage treatment facilities based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment unit , An alternative application unit for applying an alternative derived from the alternative derivation unit to an individual sewage treatment facility and a statistical model for predicting the amount of generated dehydrating sludge and the amount of generated digestion gas by applying a regression analysis technique, And an integrated environmental impact prediction unit capable of predicting an environmental impact on an alternative applied from the alternative application unit.

Further, according to the present invention, from the database storing the process operation data and various data including the aeration amount of the sewage treatment facility, the sludge disposal amount, the sludge return amount, the drug injection amount, the power consumption amount, the sedimentation ability, A data calling step for automatically calling important data related to an environmental impact on a sewage treatment facility including at least one of a chemical amount, a discharged water quality, a bioreactor, a CO ₂ and NO ₂ emission amount of the digester, and a dehydrated cake amount; The environmental impact assessment techniques are applied to the called data to classify the data related to the environmental impact by the environmental impact category and multiply the classified data by the characteristic factor for each environmental impact category to characterize the classified data An individual environmental impact assessment step of deriving the environmental impact indicators of the individual sewage treatment facilities including the global warming, eutrophication, acidification, and human toxicity, and evaluating the environmental impacts of the individual sewage treatment facilities; And an integrated alternative presentation step of integrating and managing sludge for a plurality of sewage treatment facilities by presenting a slip treatment alternative with the least environmental impact based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment step ; And a sludge integrated management method for a plurality of sewage treatment plants using an environmental impact assessment.

Meanwhile, in the integrated alternative presentation step, various alternatives that can minimize environmental impacts on a plurality of sewage treatment facilities are derived based on the environmental impact indicators of individual sewage treatment facilities derived from the individual environmental impact assessment stages, A statistical model for predicting the amount of dewatered sludge generated and the amount of generated digestion gas is derived by applying the regression analysis technique to the individual sewage treatment facilities and the statistical model is used to estimate the environment for the alternative applied to the individual sewage treatment facility And suggests an optimal sludge management alternative for many sewage treatment facilities.

Although the environmental impact assessment for the existing sewage treatment facilities has not been shown as an objective result in comparison with a number of sewage treatment facilities by evaluating the sewage treatment facilities as a qualitative indicator, , It is classified into each impact category from the data items according to the classification of the sewage treatment plant, and ultimately it is derived as acidification, global warming, eutrophication, and human toxicity value, giving the operator of the sewage treatment plant a convenient visual effect to compare and analyze the environmental impact of each sewage treatment facility And it has an effect of helping to operate an efficient sewage treatment plant.

In addition, in the environmental impact assessment for existing sewage treatment facilities, the treatment steps that have the greatest influence on the environment from the power consumption of the sewage treatment plant, the amount of the chemicals used, the environmental impact upon the final treatment of the sludge, Or providing environmental information to the sewage treatment plants, or performing environmental impact assessments on a number of sewage treatment plants to provide information for finding the sewage treatment process with the lowest environmental impact. However, And the sludge integrated management alternatives are derived based on the results of the environmental impact assessment. Thus, the most suitable sludge integrated management alternatives for sewage treatment facilities in the area can be finally presented.

FIG. 1 is a block diagram showing a sludge integrated management system for a plurality of sewage treatment plants using an environmental impact assessment according to an embodiment of the present invention.
2 is a flowchart showing a sludge integrated management method for a plurality of sewage treatment facilities using environmental impact assessment according to an embodiment of the present invention.
3 is a unit process flow diagram for an individual sewage treatment facility in an embodiment of the present invention.
FIG. 4 is a configuration diagram for environmental impact assessment for the individual sewage treatment facility of FIG. 3; FIG.
FIG. 5 is a diagram showing the results of the environmental impact assessment for the individual sewage treatment facility of FIG. 3; FIG.
Figure 6 is a diagram showing the results of environmental impact assessment for integrated management of the individual sewage treatment plants of Figure 3;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to constituent elements of each drawing, it should be noted that the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a block diagram showing a sludge integrated management system for a plurality of sewage treatment facilities using environmental impact assessment according to an embodiment of the present invention. FIG. 3 is a flow chart of a unit process for an individual sewage treatment facility in an embodiment of the present invention, and FIG. 4 is a flowchart illustrating an environmental impact assessment for the individual sewage treatment facility of FIG. FIG. 5 is a view showing the result of environmental impact assessment for the individual sewage treatment facility in FIG. 3, and FIG. 6 is a view showing the result of environmental impact assessment for integrated management for the individual sewage treatment facility in FIG. 3 to be.

1, a sludge integrated management system 10 for a plurality of sewage treatment plants using an environmental impact assessment according to the present invention includes a data calling unit 100, an individual environmental impact assessment unit 200, and an integrated alternative presentation unit 300).

The data calling unit 100 is connected to a database that stores process operation data including aeration amount of the sewage treatment facility, sludge waste amount, sludge return amount, drug injection amount, power consumption amount, sedimentation ability, And it calls the data necessary for integrated management of the sludge in the sewage treatment facility.

Therefore, the data calling unit 100 can pre-select the data necessary for sludge unification management of the actual sewage treatment facility from the various input data, and can call data on a daily basis. That is, the data calling unit 100 can automatically call the main data related to the environmental influence of the sewage treatment facility among all the data of the industry accumulated in the database, which is separately operated in the individual sewage treatment facility. In particular, key data relevant to the environmental impacts of the sewage treatment facilities may consist of at least one of the following: electricity, chemicals, effluent water, bioreactor, CO ₂ and NO ₂ emissions from the digester, have.

The individual environmental impact assessment unit 200 classifies data that are related to environmental impact by applying environmental impact assessment techniques to the called data, and characterizes the classified data using characteristic factors for each environmental impact category It serves to assess the environmental impacts of individual sewage treatment plants by deriving environmental impact indicators for individual sewage treatment facilities, including global warming, eutrophication, acidification and human toxicity. The individual environmental impact assessment unit 200 includes a data classification unit 210 that classifies data related to environmental impacts by environmental impact categories by applying environmental impact assessment techniques to the called data, A data characterization unit 220 for characterizing the classified data by multiplying the data by characteristic factors for each environmental impact category, and a data characterization unit 220 for characterizing the classified data by constituting environmental impact indicators including global warming, eutrophication, acidification and human toxicity And an individual environmental influence index derivation unit 230 for deriving the individual environmental influence index derivation unit 230 as parameters.

The integrated alternative presentation unit 300 may present a slip treatment alternative with the least environmental impact based on the environmental impact index of the individual sewage treatment facility derived from the individual environmental impact assessment unit 200, Sludge is integrated and managed. On the other hand, the integrated alternative presentation unit 300 may include various alternatives that can minimize environmental impacts on a plurality of sewage treatment facilities based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment unit 200 An alternate application unit 320 for applying an alternative derived from the alternative derivation unit 310 to an individual sewage treatment facility, and an alternative application unit 320 for applying a regression analysis technique to calculate the amount of dehydrated sludge generated and the amount of generated digestion gas And an integrated environmental effect predicting unit 330 for predicting an environmental effect on an alternative applied from the alternative application unit 320 using the statistical model.

The sludge integrated management method for a plurality of wastewater treatment facilities using the environmental impact assessment according to the present invention will be described with reference to FIG.

The first step is to calculate the amount of electricity and chemicals from the database storing the process operation data and various data including the aeration amount of the sewage treatment facility, sludge waste amount, sludge return amount, drug injection amount, power consumption amount, sedimentation ability, A data retrieval step for automatically calling important data related to an environmental influence on a sewage treatment facility including at least one of discharged water quality, bioreactor, CO ₂ and NO ₂ emissions of the digester, and dehydrated cake amount (S110 ).

In the second step, environmental impact assessment techniques are applied to the called data to classify data related to the environmental impact into environmental impact categories, and multiply the classified data by characteristic factors for each environmental impact category, And an environmental impact indicator for individual sewage treatment facilities including global warming, eutrophication, acidification, and human toxicity, and evaluating the environmental impacts of the individual sewage treatment facilities (S120).

In the present invention, the operation process of the sewage treatment facility is divided into four unit processes such as a sewage treatment line, a sludge treatment line, a sludge transportation and a landfilling process, and data collection is performed or acquired or calculated through a sewage treatment site, a database, and literature. Here, the data are largely divided into input and output items according to each unit process. Inputs include electric power and chemicals. Outputs include discharged water, which is a major product of the sewage treatment unit process, and atmospheres Emissions, water-based emissions, solid waste, and the like.

On the other hand, after collecting all collected data into input / output according to four unit processes, detailed data items of input / output of each unit process are already classified by the environmental engineers and environmental experts based on the scientific basis The groups were classified into environmental impact indicators including acidification, eutrophication, global warming, and human toxicity according to their respective impact categories. For example, items such as carbon dioxide, methane, and NO2 affect the global warming category, and substances such as COD, T-N, T-P, and PO4- affect the eutrophication category. The data items separated by each impact category will appear as a final environmental impact assessment using the corresponding factor (factor) for each impact category, ultimately indicating the potential contribution to global warming, acidification, eutrophication, and human toxicity, 5.

The third step is to integrate and manage the sludge for many sewage treatment facilities by presenting the lowest environmental impact slope treatment alternatives based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment stages (S130). Meanwhile, the integrated alternative presentation step (S130) may include various alternative methods for minimizing environmental impacts on a plurality of sewage treatment facilities based on the environmental impact indicators of individual sewage treatment facilities derived from the individual environmental impact assessment step (S120) A statistical model for predicting the amount of dewatered sludge generated and the amount of generated digestion gas is derived by applying a regression analysis technique to the individual sewage treatment facility, , It is possible to suggest an optimal sludge management alternative for many sewage treatment plants.

In the present invention, after the environmental impact assessment for the individual sewage treatment facility is performed in the second step (S120), a sludge capable of collectively managing the dewatering cakes of a plurality of sewage treatment facilities in the zone in the third step (S130) Derive integrated management alternatives. In order to compare the environmental impacts of the existing individual operating conditions, we used a regression analysis technique to predict the environmental impacts when implementing the integrated management alternatives. We propose a model. In the model for predicting the amount of dewatered cake, the independent variables are sludge generation amount, digestion tank inflow amount, digestion tank TS (total sludge amount), digested tank mixed inflow sludge and digestion tank withdrawal amount in each sewage treatment facility, independent variables in digestion gas prediction model, digestion tank inflow amount, TS, digestion tank VS (volatile sludge amount), and digestion tank solid matter removal amount. We used 100 data sets of existing sewage treatment plants to develop the prediction model.

In addition, in the present invention, the predicted values of the geographical distribution, the transportation distance, the number of transportation, and the light oil cost between the sewage treatment facility and the landfill are derived for the environmental load and the cost incurred in the transport of the dehydrated sludge. In addition, according to the outline of sewage sludge resource reclamation, the unit cost for composting, incineration and landfilling of dehydrated cakes and the cost reduction due to energy recovery during dehydration cake treatment are derived together, Respectively.

Finally, when applying the integrated sludge management alternative derived in the third step (S130), the most suitable alternative is presented by comparing the environmental impacts and the environmental impacts of the existing individual sewage treatment facilities, respectively. This result is shown in FIG.

Hereinafter, the sludge integrated management method for a plurality of wastewater treatment facilities using the environmental impact assessment referred to in the present invention will be described based on the embodiments.

In this embodiment, the characteristics of the respective treatment processes and the daily operational data were collected for the three sewage treatment facilities (WWTP-N, WWTP-S and WWTP-G) The operating information of the three sewage treatment facilities examined in advance is shown in [Table 1]. The system scope of the present invention included the operation, transportation, landfill, power and drug production processes of three sewage treatment plants. Specifically, as shown in FIG. 3, the treatment and transportation of biomass, biogas and dehydrated cake generated in the sewage treatment and sludge treatment stages in each sewage treatment facility, and the environmental effects such as required power consumption and chemical consumption amount are considered . At this time, the input and output data associated with the sewage treatment process, the sludge treatment process, the dehydrated sludge transportation process, and the sludge landfill process are called from the operation database of the sewage treatment facility.

Sewage treatment method Drug type Sludge
Processing method Dehydrated sludge
Processing method Presence of renewable energy To landfill
Shipping distance N WWTP Standard Activated Sludge Process Coagulant
Hypochlorous acid Anaerobic digester Landfill has exist 29.0 km S WWTP A2O method Coagulant
Hypochlorous acid polychlorinated aluminum Anaerobic digester Landfill has exist 14.4 km G WWTP MLE method Coagulant
Hypochlorous acid Sludge dewatering Landfill none 10.1 km

The functional unit was set to 1 m ³ and the data collection range was divided into sewage treatment line, sludge treatment line and landfill process as shown in [Table 2]. The data items were water quality of sewage treatment plant, power consumption, drug consumption, sludge and biomass production, renewable energy consumption, transportation distance to landfill, and actual operating data collected in 2012. Among them, air emissions such as CO ₂ , N ₂ O, and ammonia, COD, nitrate (NO ₃ ), and phosphorusmatter generated during truck transportation, power production and chemical production process are based on the national LCI database And the amount of greenhouse gas and methane gas generated when the dehydrated cake was buried was estimated from the Ecoinvent Database included in Gabi Software.

At this time, the list of all data collected and calculated is shown in [Table 2]. The amount of CO ₂ and CH ₄ emissions from digestion tank (Allen et al., 1997) was based on CO ₂ : CH ₄ = 35: 65, The following CO ₂ and NO ₂ values are finally obtained through the average level variable set by the organization.

Bioreactor CO ₂ emission formula = 0.3 kg CO ₂ / per kg BOD * Amount of BOD removed

Bioreactor NO ₂ Emission Calculation Formula = 0.61 g / m ² * Aeration tank area

Digester CO ₂ and CH ₄ formula

Digester CO ₂ = digestion gas production * 0.35

Digester CH ₄ = digestion gas production * 0.65

Emission line Data contents Data Sources Wastewater
처리 라인 Influent and effluent composition (COD, BOD, SS, T-P, T-N) Sewage treatment plant actual operating data measurement Electricity Consumption Sewage treatment plant actual operating data measurement PAC Consumption Actual operational data measurement CO ₂ Production Calculated N ₂ OProduction Calculated Sludge
처리 라인 Sludge Production Sewage treatment plant actual operating data measurement Electricity Consumption Sewage treatment plant actual operating data measurement Renewable energy Consumption Digitized gas generation design standard data Chloric acid Consumption Actual operational data measurement PAAConsumption Actual operational data measurement CH ₄ Production Calculated CO ₂ Production Calculated Dewatered sludge Production Actual operational data measurement Landfill process CH ₄ Production Ecoinvent Database CO ₂ Production Ecoinvent Database

From the derived operating procedure input and output data lists, we perform impact assessments that indicate acidification, eutrophication, global warming, and human toxicity, respectively. First, classification of data items according to each environmental impact indicator was performed, and the classified state is shown in FIG. The environmental load of each sewage treatment operation collected and classified is multiplied by the corresponding characterization index to represent the total amount of carbon dioxide, the total amount of sulfur dioxide, the total amount of phosphate, and the total amount of 1,4 DCB. The characterization formula used in the calculation is as follows.

EF (j) i = Σ [Q (j)) i * EF (j) i]

The eutrophication (j) is the potential impact value on the j-type environmental impact indicator in all inputs / outputs in the system range, the eutrophication (j) i is the impact value of the environmental load of i on the j- j) i is the environmental load of i type, EF (j) i is the environmental load of i type, and j is the characterizing factor for environmental impact.

There is a need to predict the amount of dehydrated cake and the amount of digestion gas generated when implementing integrated management alternatives for the three sewage treatment plants to compare the current operational status and environmental impacts. The regression equation of dehydrated cake quantity obtained correlation value from 100 data in 2012 at S WWTP establishment. Estimation of the amount of dehydrated sludge generated at existing G WWTP establishments and the amount of digested tank inflow from TS and S WWTP establishments and the withdrawal amount of sludge and digesters from S WWTP sites. The withdrawal rate of the digestion tank obtained from this was highly correlated with the amount of dehydrated cake, and the regression equation obtained was as follows.

Drainage cake amount (ton / d) = 2212.17 + 0.9 * Drainage amount (m ³ / d)

At this time, the derived regression analysis determination coefficient (R ² ) was 0.7 and the standard error was 5934.

The amount of digestion gas generated is derived from the digestion tank inflow, digestion tank TS, digestion tank VS, and digestion tank solid matter removal amount. The variables with the highest correlation are TS, TS, and solid matter removal. The regression equation is as follows.

Extinguishing gas generation amount (m ³ /d)=12413.82+0.03* digester inlet TS (mg / l) + 0.267 * 1 primary digester TS (mg / l) + 0.015 * Removed solid amount (kg / d)

At this time, the coefficient of determination (R ² ) of the regression analysis is 0.25 and the standard error is 2481.

The S-WWTP primary sedimentation tank inflow and TS were 2,007 m ³ / d and 35,296 mg / L, respectively, derived from the above predictive model formula. From the first digestion tank digestion rate of 47%, the second digestion tank sludge solid volume of 37,545 kg, Assuming that the amount of sludge solid in the digester is equal to the amount of withdrawal in the digestion tank, the digested sludge dewatering cake thus obtained was 36,002 kg and the total sludge cake production was 160.725 t when the water content was 77.6%.

According to the distance from the three sewage treatment facilities to the landfill, the dehydrated cake transportation process considers 2 times as one round trip, and when it is transported by truck of about 20 tons capacity, mileage per 1L of light oil is 7.2km, diesel price is 1,690 won / L (Korea National Oil Corporation), the environmental load and cost of the dewatered sludge transportation process were derived according to the daily mean dehydration cake amount generated at each sewage treatment plant.

Investment costs and operating costs for the three sewage treatment plants are based on the operating data for 2008 provided by each establishment. According to the Korea Environment Corporation's Sewage Sludge Recycling Overview, the cost for composting dewatered sludge cake is 41,000 won / ton, the incineration cost is 46,900 won / ton, and the disposal cost for landfill is 38,557 won / Ton. Incineration heat generated during incineration is recovered as steam (65 ~ 75% of total heat) in the waste heat boiler, and maximum calorific value of domestic sewage sludge is about 500 Kcal / kg.

Using the environmental impact assessment model in the present invention, the results of the environmental impact assessment were classified into the sewage treatment stage, the sludge treatment stage, and the landfill stage in the current operation state of the three sewage treatment plants. The energy consumption was about 74%, and consumed 23% of power in the sludge treatment stage. The results of the environmental impact assessment for the three sewage treatment plants are shown in Table 3 below. Acidification, global warming and human toxicity in the sewage treatment stage accounted for about 76%, 83% and 78% of the total environmental load, respectively, and about 21%, 7% and 20% respectively in the sludge treatment stage. Eutrophication occurred at the sewage treatment stage and the final result was negative. In the whole sewage treatment plant operation, about 114 kg of PO ₄ - was released into the soil and air in the sludge disposal and landfilling stages, but 33,785 kg of PO ₄ - eutrophication was removed in the sewage treatment stage And it can be beneficial for the environment.

Energy Consumption
(KWh / d) Eutrophication
(kgPO4-Equiv.) acidification
(kgSO2-Equiv.)
Global warming (100 years)
(kgCO2-Equiv.) Human toxicity
(kgDCB-Equiv.) value % value % value % value % value % Wastewater treatment line 589,556 74% -33,785 100% 417 76% 431,871 83% 4,884 78% WWTP-S 354,795 44% -28,905 86% 249 45% 365,702 70% 2,894 46% WWTP-G 63,620 8% -1,499 4% 46 8% 19,270 4% 539 9% WWTP-N 171,141 21% -3,381 10% 123 22% 46,900 9% 1,450 23% Sludge
처리 라인 186,927 23% 12 <1% 116 21% 35,016 7% 1,261 20% WWTP-S 113,107 14% 7 <1% 69 13% 21,048 4% 751 12% WWTP-G 20,353 3% One <1% 13 2% 3,836 One% 139 2% WWTP-N 53,467 7% 3 <1% 34 6% 10,131 2% 370 6% Landfill
process 21,666 3% 102 <1% 19 3% 55,285 11% 142 2% WWTP-S 11,114 One% 53 <1% 10 2% 28,732 6% 73 One% WWTP-G 2,696 <1% 13 <1% 2 <1% 7,035 One% 18 <1% WWTP-N 7,856 One% 36 <1% 7 One% 19,518 4% 51 One%

The resulting contribution of environmental impacts was further subdivided at each treatment stage and the amount of pollutants generated from the six unit functions at the time of sewage treatment was deduced from the energy consumption, acidification, global warming, eutrophication, Is calculated as a ratio and is shown in Fig. The effects on acidification and human toxicity were mainly dependent on the energy consumption, and the power consumption function of sewage treatment step, which consumes the most power, accounted for 80% of the total. The effect on global warming was N WWTP, Step power consumption function accounted for 50%, followed by sludge landfill function 30%. Although the concentrations of influent in three treatment plants did not show a significant difference, S WWTP was treated with a lower water quality standard than other treatment plants in the A ₂ O process, so the release of S WWTP from the bioreactor CO ₂ was higher than the other two treatment plant bioreactors. Therefore, to improve the effects on acidification, global warming, and human toxicity, it will be necessary first to find alternatives to reduce power consumption during sewage treatment. It would be a good alternative to reduce traditional energy use by producing renewable energy from biogas.

After obtaining the results of the environmental impact assessment for the three sewage treatment facilities, the integrated management alternatives as shown in [Table 4] were set up as the preliminary steps for the integrated management. Based on the environmental impact assessment for the three alternatives, And provided decision-making support measures to adopt positive alternatives.

Case Process Management alternatives Case 0 Present situation WWTP-S, WWTP-N: Embank dehydrated cake treated with anaerobic digestion
WWTP-G: Landfill after dehydration of concentrated sludge Case 1 Landfill The WWTP-G dehydrated cake was introduced into the WWTP-S digester, anaerobically digested, and the digested gas was used to produce electricity. Case 2 Incineration All three treatment plant dehydration cakes are incinerated to produce electricity and the residue is buried Case 3 Compost Composting of all three dehydration cake processing plants

Case 1, Case 2, Case 3 The results of the environmental impact assessment that occurs in the current operating state when the alternative is executed are shown in FIG. Comparing Case 0 with the three operating alternatives, the first case consumes the smallest amount of power when the Case 1 alternative is applied, and the Case 2 and Case 3 power consumption do not show much difference from the current operating state. The effect of acidification was the lowest in Case 1, because the biogas power generated in the implementation of Case 1 alternative reduced total power usage. Comparing the effects of eutrophication, Case 3 showed higher eutrophication effects than the present condition due to the nutrient salts released into the soil during sludge composting process. The global warming effect is shown to be less than the current state of affairs, and we confirmed that global warming was reduced the most when Case 1 alternative was implemented. Human toxicity was reduced by 50% compared with the current state in Case 1 and decreased by 15% in Case 2. However, the toxicity of human toxicity was doubled compared to the current operating state due to heavy metals released to soil during Case 3 Respectively. From this point of view, Case 1 is considered as the most important consideration from the environmental point of view.

Table 5 shows the economical analyzes of the three alternatives for sludge treatment, including biogas production by anaerobic digestion, transportation costs for landfill, energy recovery by incineration, and composting. Finally, it was confirmed that the new renewable energy gain obtained from Case 1 is more than the added transportation cost, so that the final operating cost is $ 942 / day. In case 2, the gain of $ 1,847 / day is more than the current operating cost and minimizing sludge throughput caused by sludge incineration is considered as an alternative to consider when preparing landfill. Although Case 3 shows that the operating cost is about $ 100 / day more than the current operating alternative, it can be used as a soil remediation agent by recycling large amounts of organic and nitrogen nutrients contained in sewage sludge, . Therefore, there is no big difference between the three alternatives economically, so it can be designed as needed.

Case Landfill
cost incineration
cost Composting cost Biogas power production Incineration energy Power output Transfer cost Sum
Case 0 -1,997 - - 52,643 - -117 50,528 Case 1 -1,900 - - 53,496 - -125 51,470 Case 2 - -2,429 - 52,643 2,279 ⁵ -117 52,375 Case 3 - - -2,124 52,643 - -117 50,402

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the embodiments disclosed in the present specification are intended to illustrate rather than limit the present invention, and the scope and spirit of the present invention are not limited by these embodiments. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of the present invention should be construed as being included in the scope of the present invention.

10: Integrated sludge management system for many sewage treatment facilities
100: Data calling unit
200: Individual Environmental Impact Assessment Department
210:
220: Data Characterization Unit
230: Individual Environmental Impact Indicators
300: Integrated Alternative Presentation
310: alternative derivation part
320: Alternative Application Section
330: Integrated environmental impact prediction unit

Claims (7)

From a database storing process operation data and various data including sewage treatment facility aeration, sludge disposal amount, sludge return amount, drug injection amount, power consumption amount, sedimentation ability and suspended solids concentration in reactor, A data calling unit for calling necessary data;
Eco-efficiency, acidification, and human toxicity by classifying data that are related to environmental impact by applying environmental impact assessment techniques to the called data, and characterizing the classified data using characteristic factors according to environmental impact categories. An individual environmental impact assessment unit that evaluates the environmental impacts of the individual sewage treatment facilities by deriving the environmental impact indicators of the individual sewage treatment facilities involved; And
And an integrated alternative proposal unit for integrating and managing sludge for a plurality of sewage treatment facilities by presenting a slip treatment alternative with the least environmental impact based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment unit Sludge Integrated Management System for Multiple Sewage Treatment Facilities Using Environmental Impact Assessment.
The method according to claim 1,
Wherein the data calling unit automatically calls up important data related to the environmental impact of the sewage treatment facility among all the data of the industry stored in a separate database operated by the individual sewage treatment facility, Sludge Integrated Management System for Wastewater Treatment Facilities of.
3. The method of claim 2,
The main data that are relevant to the environmental impacts on the sewage treatment facility include at least one of the amount of electricity, the amount of chemicals, the quality of discharged water, the bioreactor, the amount of CO ₂ and NO ₂ emissions of the digester, and the amount of dehydrated cake. Sludge Integrated Management System for Multiple Sewage Treatment Facilities Using Evaluation.
The method according to claim 1,
The individual environmental impact assessment unit may include a data classifier for classifying data related to environmental impacts by environmental impact categories by applying environmental impact assessment techniques to the called data, A data characterization unit for characterizing the classified data by multiplying the characteristic factors by the characteristic factors and an individual environmental effect index derivation unit for deriving the characterization data as factors constituting the environmental impact indicators including global warming, eutrophication, acidification and human toxicity A sludge integrated management system for a plurality of sewage treatment facilities using an environmental impact assessment.
The method according to claim 1,
Wherein the integrated alternative presentation unit includes an alternative derivation unit for deriving various alternatives that can minimize environmental impacts on a plurality of sewage treatment facilities based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment unit, An alternate application for applying alternatives derived from alternate derivation to individual sewage treatment plants and a statistical model for predicting the amount of dehydrated sludge generated and the amount of generated digestion gas by applying a regression analysis technique are derived, And an integrated environmental impact prediction unit capable of predicting an environmental impact on an alternative applied from the application unit. The sludge integrated management system for a plurality of sewage treatment facilities using environmental impact assessment.
From the database storing the process operation data and various data including the aeration amount of the sewage treatment facility, the sludge waste amount, the sludge return amount, the drug injection amount, the power consumption amount, the sedimentation ability and the suspended substance concentration in the reaction tank, A data retrieval step of automatically calling important data related to an environmental impact on a sewage treatment facility including at least one of a bioreactor, a CO ₂ and NO ₂ emission amount of the digester, and a dehydrated cake amount;
The environmental impact assessment techniques are applied to the called data to classify the data related to the environmental impact by the environmental impact category and multiply the classified data by the characteristic factor for each environmental impact category to characterize the classified data An individual environmental impact assessment step of deriving the environmental impact indicators of the individual sewage treatment facilities including the global warming, eutrophication, acidification, and human toxicity, and evaluating the environmental impacts of the individual sewage treatment facilities; And
An integrated alternative presentation step of integrating and managing sludge for a plurality of sewage treatment facilities by suggesting a slip treatment alternative with the least environmental impact based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment stages; A method of integrated management of sludge for a number of sewage treatment plants using environmental impact assessment.
The method according to claim 6,
In the integrated alternative presentation step, various alternatives for minimizing environmental impacts on a plurality of sewage treatment facilities are derived based on the environmental impact indicators of the individual sewage treatment facilities derived from the individual environmental impact assessment stages, Are applied to individual sewage treatment plants and regression analysis techniques are applied to derive statistical models for predicting the amount of dewatered sludge generated and the amount of generated digestion gas and using the statistical model to determine the environmental impacts of the alternatives applied to the individual sewage treatment plants And suggesting optimal sludge integrated management alternatives for a plurality of sewage treatment plants by predicting the environmental impact of the sludge.

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