KR20060116608A - Advanced nutrient removal system; anr - Google Patents

Abstract

A method and an apparatus for advanced treatment of wastewater by improving the activated sludge process are provided to remove residual suspended solids and dissolved organic matters by installing an aerobic biofilm filter tank, improve nitrification efficiency of the aerobic tank by supplying a portion of nitrifying microorganisms cultured in the aerobic biofilm filter tank using backwashing water, and control concentration of total nitrogen of final effluent by returning treated water of the aerobic biofilm filter tank to an anoxic tank. A method for advanced treatment of wastewater by improving the activated sludge process comprises the processes of: (i) installing an internal partition wall in an aerobic tank to divide the aerobic tank into an anoxic tank(101) and an aerobic tank(102); (ii) passing treated water of the aerobic tank through a secondary settling basin(103) and an aerobic biofilm filter tank(104) in which hydrophilic filter media are filled; (iii) discharging treated water of the aerobic biofilm filter tank through a treated water tank(105); (iv) injecting an inorganic coagulant into the front of the secondary settling basin to remove phosphorous from wastewater; and (v) supplying a portion of backwashing water(109) containing high concentration nitrifying microorganisms of the aerobic biofilm filter tank, and transferring the rest of the backwashing water to the front of a primary settling basin(111) in order to improve nitrification efficiency of the aerobic tank.

Description

Advanced treatment method and apparatus for improving activated sludge method [Advanced Nutrient Removal System; ANR}

1 is a water treatment system diagram of a reactor used in the present invention,

2 is a water treatment system diagram of an activated sludge method used as a comparative example of the present invention.

3 is a water treatment system diagram of a cyclic nitric oxide denitrification method used as a comparative example of the present invention.

`` Explanation of symbols for major parts of drawings ''

100, 20, 30: sewage inflow (primary sediment overflow) 101, 31: anaerobic tank,

102, 21, 32: aerobic tank, 103, 22, 33: secondary secondary battery 104: aerobic biofilm filtration tank,

105: treated water tank, 106, 23, 34: discharge, 107, 24, 35: conveying sludge,

108, 36: internal return, 109: backwash, 110: backwash inflow,

111: preliminary primary battery, 112: return II, 113: backwash water inflow

The present invention relates to an advanced treatment method and apparatus for improved activated sludge method. Referring to FIG. 2, as the activated sludge water treatment system flows, sewage flows in and some of the suspended solids are removed from the primary settler, and organic matter is removed from the aerobic tank 21, and discharged after separation of the solid solution from the secondary settler 22. 23, the precipitated sludge flows into the aeration tank 21 by conveyance. In the case of activated sludge method, the removal of nutrients such as nitrogen and phosphorus is mainly limited because the removal of organic matter is improved. The cyclic nitrification and denitrification method is applied as shown in FIG. 3. Referring to the process of Figure 3, the sewage flows in 30, denitrification occurs in the anoxic tank 31, the organic components are partially removed at the same time as the ammonia nitrogen oxidation in the aerobic tank 32, ammonia nitrogen is nitrate nitrogen It is oxidized and discharged after solid-liquid separation from the secondary needle battery 33. At this time, the conveying sludge 35 is introduced into the oxygen-free tank 31, and performs the internal transport 36 of the nitrifying liquid of the aerobic tank for denitrification, and the phosphorus component is cell-synthesized in the aerobic tank 32 to remove some biologically. However, if the conventional cyclic nitrification and denitrification method is applied only when the conversion to the advanced treatment does not increase the bioreactor, the residence time of the aerobic tank 32 necessary for the advanced treatment of nitrification and denitrification is often insufficient, and thus the removal rate of organic matter is low. Due to the low concentration of nitrifying microorganisms, there are limitations in application such as low efficiency in oxidizing ammonia nitrogen in sewage to nitrate nitrogen and poor sludge sedimentation, resulting in deterioration of final treated water. In addition, the above problems still remain even if the existing sewage treatment plant is retrofitted with a conventional technique and a filter paper is installed at the rear stage. In other words, if the treated water containing unoxidized ammonia nitrogen and high concentrations of organic matter is discharged as it is, it may cause problems such as fish death by depleting oxygen in the discharge water.

Therefore, the present invention is to be converted to the cyclic nitrification denitrification without increasing the bioreactor of the conventional activated sludge method, to compensate for the above disadvantages. That is, the inner bulkhead is installed in the aerobic tank 21 of the activated sludge method and divided into the anoxic tank 101 and the aerobic tank 102, and oxidation of unoxidized ammonia nitrogen and secondary secondary battery 33 in the cyclic nitric oxide denitrification method. In order to prevent the discharge of treated water containing a large amount of overflowed floc (FLOC), the aerobic biofilm filtration tank 104 is installed at the rear end of the secondary sedimentation battery 103 to solve the problems of the prior art. That is, the aerobic biofilm filtration tank 104 is installed to remove residual suspended matter (SS) and dissolved organic matter, and to reverse the part of the nitrification microorganisms cultured in the aerobic biofilm filtration tank 104 to improve the nitrification efficiency of the aerobic tank 102. A method of supplying 110 to the aerobic tank 102 using the wash water was devised. In addition, it is designed to control the total nitrogen (TN) concentration of the final discharged water if necessary by adjusting the amount of return by adding a function to return the treated aerobic biofilm filtration tank 104 to the anaerobic tank 101 (112). It was.

Referring to FIG. 1 to achieve the above-described purpose, in the case of the aerobic tank 21 of the activated sludge method, the hydraulic stay time (HRT) is usually 6 hours. The anaerobic tank 101 having the time HRT and the aerobic tank 102 having the hydraulic stay time HRT of about 4 hours are divided, and an aerobic biofilm filtration tank 104 is installed at the rear end of the existing secondary sedimentation cell 103. The reason for installing the aerobic biofilm filtration tank 104 in the present invention can be described in two ways. First, when treatment efficiency deteriorates in the circulating nitric oxide denitrification process installed at the front end, it is to oxidize ammonia nitrogen in the Kjeldahl nitrogen component to nitrate nitrogen while removing the remaining organic matter and suspended solids (SS). Second, the supply of the nitrifying microorganisms of the reaction tank (104) to the aerobic tank (102) using a backwash water (110), and the nitrogen removal efficiency is dramatically improved when nitrogen removal conditions, such as winter, is a key technology of the present invention. . In addition, a storage tank and a quantitative injection device for nitrifying microorganisms may be provided to supply an appropriate amount of nitrifying microorganisms to the aerobic tank 102, and a return II line 112 is installed to control nitrogen removal efficiency according to the discharge target water quality.

Hereinafter, the present invention will be described in more detail with reference to Comparative Examples and Examples.

`` Comparative Example 1 ''

In order to construct an activated sludge method as shown in FIG. 2, a model is constructed of an aerobic tank 21 (capacity: 0.6 m 3), an air diffuser for supplying air, and a secondary sedimentation battery 22 (capacity: 0.48 m 3). It was. The sedimentation sludge of the secondary sedimentation cell 22 is returned to 1Q (flow rate, unit: m 3 / day, denoted as Q below) by using a metering pump, and the waste sludge is drawn out once every three days, and the concentration of microorganisms in the aerobic tank is Was adjusted. For the treatment water, sewage from the ○ ○ sewage treatment plant (Active Sludge) located in Gyeonggi-do was used based on the monthly water quality of the primary sedimentation wastewater at the sewage treatment plant. The inflow water 20 was introduced into the aerobic tank 21 as a metering pump, and the microorganisms were planted in the aerobic tank 21, the microorganisms were activated for 7 days, and then the experiment was performed for 70 days. A temperature of 17 ° C. was maintained for reproducibility of the test results, and the results of influent quality and operation are summarized in Table 1. (Unit: mg / ℓ, data is an average value) The reason why the water temperature was selected as 17 ℃ in all the examples compared in the present invention in order to highlight the effect of the present invention when the nitrification decreases during the autumn and winter low water temperature. to be.

<Table 1> Result summary of Comparative Example 1

`` Comparative Example 2 ''

In order to configure the circulatory nitrification and denitrification method as shown in FIG. At this time, the aerobic tank 21 (capacity: 0.6 m 3) was divided into an anaerobic tank 31 (capacity: 0.2 m 3) and an aerobic tank 32 (capacity: 0.4 m 3) by installing an internal partition. In addition, the mixed liquid of the aerobic tank 32 was subjected to the internal conveyance 36 to the anoxic tank 31 under 2Q (where Q is the amount of work sewage) conditions (0.5 to 4Q), and was tested at a sludge conveyance rate of 1Q. The operating period was operated under the same conditions as in <Comparative Example 1>. Detailed operating conditions and experimental results are summarized in <Table 2>. (Unit: mg / l, data is average)

<Table 2> Summary of results of Comparative Example 2

As a result of the experiment, BOD, COD, and SS were almost equivalent to Comparative Example 1 (activated sludge method), and the treatment efficiency was improved in nitrogen removal.

<< Example 1 >>

In order to compare the treatment performance with the water treatment system according to the present invention, a model facility having the same scale as that of Comparative Example 2 was used. In addition, an aerobic biofilm filtration tank 104 (capacity: 0.1 m 3) and a treatment water tank 105 were provided at the rear end of the secondary needle battery 103. In addition, an aerobic device is installed in the lower portion of the aerobic biofilm filtration tank 104 and filled with gravel and a hydrophilic filter medium. The microorganisms of the initial aerobic biofilm filtration tank 104 in operation were injected and activated by injecting the same microorganisms planted in the aerobic tank 21 of Comparative Example 1. In the case of the aerobic biofilm filtration tank 104, filtration resistance is generated when excessive growth of microorganisms or suspended matter is accumulated, and in this case, the filtration resistance is released by backwashing to normal operation. The backwashing was performed in a cycle of once every two days in combination with the treatment water of the treatment tank 105 in a metering pump, and offensive using air. In addition to the removal of biological phosphorus, inorganic coagulant was injected at the concentration of 20 mg / L in front of the secondary precipitator 103. In order to improve the nitrification efficiency of the aerobic tank 102, which is the core technology of the present invention, some nitrified microorganisms of the aerobic biofilm filtration tank 104 discharged during backwashing were supplied to the aerobic tank 102. Experimental temperature (17 ℃) and operating conditions are the same as in <Comparative Example 2> and the results are summarized in <Table 3>. (Unit: mg / l, data is average value) As a result, the treatment efficiency of each water quality is stable. In particular, despite the low water temperature of nitrogen removal efficiency is significantly improved compared to the comparative example.

<Table 3> Summary of results of Example 1

<< Example 2 >>

The experiment was carried out in the same manner as in Example 1, the amount of conveying II (112) was injected into the oxygen-free tank 101 from the treated water of the aerobic biofilm filtration tank 104 using a metering pump up to 1.0Q. However, the experiment period was carried out for 10 days for each conveyed amount. In this embodiment, the water quality other than the nitrogen-related components in the final effluent of the present invention is good, and the treatment is stably performed without modification of the treatment process in the event of an emergency or when the discharge quality of nitrogen is extremely enhanced. The results are summarized in <Table 4>. (Unit: mg / l, data is average)

<Table 4> Summary of results of Example 2

※ Note) Influent Water Quality: It is the result of the water quality due to the increase of the flow rate of the conveying II

According to the present invention, the aerobic tank 21 of the activated sludge method is installed without an increase in capacity, and only the inner bulkhead is converted into an anaerobic tank 101 and an aerobic tank 102, and an aerobic biofilm filtration tank 104 is installed at the rear end to install the aerobic tank of the biofilm filtration tank. As a high treatment process to supply 110 to 102, the disadvantages of the conventional circulating nitric oxide denitrification method have been greatly improved. The water quality is better than that of many A ² O series advanced treatment processes (BNRs), and the cost of retrofits can be reduced by making full use of existing plant facilities. Therefore, the process of the present invention is excellent in applicability in the retrofit and construction of sewage treatment plants. Eventually, the treated water treated with the present invention can be used for heavy water such as industrial water, landscaping water and toilet water, and also provides clean treated water that can inhabit fish and aquatic plants in dry streams due to urban development. By doing so, it will contribute to raising the value of water resources and creating eco-friendly ecological space.

Claims (2)

In the advanced processing of the activated sludge method, (i) dividing the aerobic tank 21 into an anaerobic tank 101 and an aerobic tank 102 by installing an inner partition; (ii) a process in which the treated water introduced from the aerobic tank 102 passes through the aerobic biofilm filtration tank 104 filled with the secondary needle battery 103 and a hydrophilic filter medium; (iii) a process in which the treated water introduced from the aerobic biofilm filtration tank 104 filled with the hydrophilic media is discharged 106 through the treatment water tank 105; (iv) a process in which an inorganic coagulant is added to the front end of the secondary sedimentation battery 103 to remove the phosphorus component, (v) a portion of the backwash water 109 including the high concentration of nitrification microorganisms of the aerobic biofilm filtration tank 104 filled with a hydrophilic filter to increase the nitrification efficiency of the aerobic tank 102 is supplied to the aerobic tank 102 (110), and the rest To transfer the primary precipitator to the previous step (111), Advanced processing apparatus improved activated sludge method, characterized in that consisting of. The method of claim 1, A water treatment method of increasing the nitrogen removal efficiency by further denitrification by returning the treated water of the aerobic biofilm filtration tank (104) filled with a hydrophilic filter to the anoxic tank (101).

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