KR100280075B1 - Sanitary Landfill Leachate Treatment Method - Google Patents

Abstract

The present invention is to provide a sanitary landfill leachate treatment method that can be applied to difficult to decomposable and high concentration wastewater treatment.

The present invention solves the problem of the scale of the leachate raw water and hardly decomposable material from the sanitary landfill, to increase the load of the anaerobic digester, and to perform the pretreatment process with iron salt to reduce the treatment period or treatment capacity In addition, by using a high-rate anaerobic digester instead of conventional anaerobic digestion, a method for treating sanitary landfill leachate that has high pretreatment efficiency, has a good effect on anaerobic operation conditions, can shorten treatment time, and can reduce treatment capacity to the maximum. It is to provide.

Description

Sanitary Landfill Leachate Treatment Methods

The present invention relates to a sanitary landfill leachate treatment method. More particularly, the present invention relates to a sanitary landfill leachate treatment method applicable to hardly degradable and high concentration wastewater treatment.

In the conventional method of treating the sanitary landfill leachate, in the process consisting of “anaerobic digestion → activated sludge → chemical agglomeration → filtration → advanced treatment”, each unit process is changed slightly according to the situation and combined.

One of these processes consists of “Aerobic Digestion → Aeration Type → Sedimentation Tank → Rotary Disc Method → Sedimentation Tank → Mixed Aggregation → Sand Filtration → Ozone Treatment (or Activated Charcoal Filtration)” (Korean Patent Publication No. 97-015493) ).

Another treatment process consists of "anaerobic digestion → activated sludge → fenton oxidation → granular activated carbon treatment" (Korean Patent Publication No. 97-042328).

On the other hand, there is also a method of treatment with a reverse osmosis membrane as a physicochemical treatment (Korean Patent Publication No. 97-010662).

In the anaerobic digestion process of the biological treatment process, a conventional anaerobic digester is used. The conventional anaerobic digester is a method of mixing microorganisms and wastewater together in the digester to have a low concentration of microorganisms in the anaerobic digester.

Therefore, the processing time takes very long, such as 10 to 20 days. Recently, attempts have been made to treat leachate using a high rate anaerobic digester (Korean Journal of Waste Management, Vol. 13, No. 2, pp. 211 (1996)).

Rotating disc method which is widely used in leachate treatment process is not easy to operate, and in particular, it is sensitive to temperature change, so it is hardly treated in winter.

Leachate is generally introduced into the anaerobic digester without pretreatment, but there is a problem in that the suspended solids (SS) present in the leachate in the actual operation is formed in the scale (pipe) in the pipe.

In the leachate treatment process, the fenton oxidation method requires excessive chemicals due to excessive use of chemicals. In particular, H ₂ O ₂ is more expensive than general wastewater treatment chemicals.

The reverse osmosis membrane method and the ozone treatment method are relatively easy to operate, but the economical efficiency is low due to excessive initial facility cost and operation management cost.

The present invention solves the problem of the scale of the leachate raw water and hardly decomposable material from the sanitary landfill, to increase the load of the anaerobic digester, and to perform the pretreatment process with iron salt to reduce the treatment period or treatment capacity In addition, by using a high-rate anaerobic digester instead of conventional anaerobic digestion, a method for treating sanitary landfill leachate that has high pretreatment efficiency, has a good effect on anaerobic operation conditions, can shorten treatment time, and can reduce treatment capacity to the maximum. The purpose is to provide.

1 is a block diagram of the sanitary landfill leachate treatment process according to the present invention.

The sanitary landfill leachate treatment method of the present invention comprises the steps of neutralizing after inputting 500 to 6,000ppm of iron salt to the leachate raw water in the pretreatment tank, and pre-treatment by mixing agglomerates by polymer coagulant; Anaerobic digestion of the iron salt agglomerated water in a high rate anaerobic digester; Passing a batch reactor to remove nitrogen and phosphorus contained in the leachate; Conducting activated sludge in an aeration tank to remove organic carbon pollutants by biological treatment; And coagulating the treated water flowing out of the aeration tank, and performing sand filtration and activated carbon filtration to reduce organic carbon pollutants and suspended solids, and then discharging the treated water with COD _cr 30 ppm or less and COD _Mn 10 ppm or less.

Hereinafter, the present invention will be described in more detail.

Sanitary landfill leachate treatment process of the present invention is composed of "flow control tank → pretreatment tank → high rate anaerobic digestion tank → batch reaction tank → aeration tank → secondary sedimentation tank → flocculation sedimentation tank → sand filtration → activated carbon filtration as shown in the block diagram in FIG. do.

In the present invention, firstly, the leachate float and the hardly decomposable material form scale in the pipe, and when the material enters the anaerobic digester, the leachate raw water is pretreated to solve the problem of increasing the load of the anaerobic digester. It will reduce hardly decomposable substances.

In the present invention, a method of pretreatment of leachate raw water consists of neutralization of 500 to 6,000 ppm of iron salt (FeCl ₃ ) with respect to leachate raw water in a pretreatment tank, followed by mixing and coagulation by polymer coagulant.

In the case of iron salt aggregation, if iron salt (FeCl ₃ ) is added less than 500ppm, no floc is formed, and flocculation does not occur.If it is added more than 6,000ppm, SV30 is 300 or more, so it is difficult to separate solid and liquid. Disappears. Therefore, it is preferable to add in the above range. Table 1 shows the results of pretreatment of leachate raw water.

Pretreatment technology Way Drug dosage COD _cr removal rate (%) Suspension removal rate (%) Iron salt coagulation FeCl ₃ + NaOH + Polymer FeCl ₃ 500 _~ 6,000ppm 15-33 72-81

According to the present invention, a high rate anaerobic digestion tank (Korean Patent Publication No. 97-15492) is used to anaerobic digestion of pretreated water.

When performing high-rate anaerobic digestion using the high-rate anaerobic digester, it is possible to shorten the treatment period by 4 days to 2 days in short, and may lower the capacity of the anaerobic digester up to 1/10 as compared to the conventional anaerobic digester. .

Results of high rate anaerobic digestion by the method of the present invention are shown in Table 2 below.

Pretreatment Technology Drug dosage Pretreatment efficiency (CODcr removal rate,%) COD _cr removal rate (%) Gas generation amount (liter) Iron salt coagulation FeCl ₃ 2500 ppm 20 93 1.4

The anaerobic digestion test was conducted by a batch bottle test (Serum bottle test) as a batch method, and sealed by adding 50 ml of an anaerobic digestion sludge to 250 ml of pretreated water adjusted to a concentration of 3,000 ppm of COD _cr in a 500 ml capacity bottle. After incubation at 100rpm in shaking culture. The amount of gas generated was measured according to the number of days passed, and a sample was taken to measure the COD _cr .

In the case of iron salt treatment according to the present invention, the pretreatment efficiency was also high, and the result of the serum bottle test was found to have a good effect on anaerobic digester operation.

Table 3 shows a comparison of the case treated with anaerobic digestion in the high rate anaerobic digester according to the present invention and the case treated in the conventional anaerobic digester.

Item Conventional Anaerobic Digester High rate anaerobic digester Processing time (days) 2 15 20 2 Raw water COD _cr concentration (ppm) 20,000 20,000 20,000 20,000 Number of driving days 90 90 90 60 COD _cr throughput rate (%) 32 79 91 93

Anaerobic Digester The following process involves a sequencing batch reactor (SBR) to remove nitrogen and phosphorus from the leachate. Batch reactor also has the function of removing the organic carbon pollution source with the removal of nitrogen and phosphorus. The process is then linked with an activated sludge process (aeration tank) to remove organic carbon pollutants as a final biological treatment.

Batch reactors and aeration tanks may be reversed in some cases.

The treated water flowing out of the aeration tank is coagulated by Alum and discharged through sand filtration and activated carbon filtration. Alum flocculation is to reduce the load of sand filter tank and activated carbon filter by minimizing suspended solids in aeration tank effluent. Sand filtration and activated carbon filtration are for the ultimate removal of organic carbon pollutants and suspended solids.

In particular, if a problem occurs in the treatment process and the treated water concentration is slightly higher outflow can be treated in a sand filter and an activated carbon filter. The treated water coarse to activated carbon filtration typically satisfies 30 ppm or less of COD _cr and 10 ppm or less of COD _Mn .

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

Example 1

The sanitary landfill leachate was treated by the “flow control tank → pretreatment tank → high rate anaerobic digestion tank → batch reaction tank → aeration tank → secondary sedimentation tank → coagulation sedimentation tank → sand filtration → activated carbon filtration” of the present invention.

Here, pretreatment, flocculation sedimentation, sand filtration, activated charcoal filtration were performed in a batch type, and high-rate anaerobic digestion tanks, batch reaction tanks, and aeration tanks were continuously treated in connection.

The high-rate anaerobic digester was 10 liters, the batch reactor was 5 liters, and the aeration volume was 5 liters. The treatment time of the high rate anaerobic digester was 2 days, the batch reactor was 2 days, and the aeration tank was 1 day. The high rate anaerobic reactor was initially started at 4,100 ppm and was operated by gradually increasing the concentration.

COD _cr of raw and treated water was measured, and COD _Mn , TN (total nitrogen) and suspended solids (SS) were also measured in some cases. The results are shown in Table 4 below.

division Days of Operation Measurement Items 10 days 30 days 50 days 60 days Pretreatment CODcr (ppm) 5,000 10,000 17,000 25,000 Treated water CODcr (ppm) 4,100 7,800 13,770 20,000 CODcr treatment rate (ppm) 18 22 19 20 Raw water effluent concentration (ppm) 72 120 240 800 Treated water float concentration (ppm) 72 74 79 72 Suspension Treatment Rate (%) 20 31 50 224 Anaerobic digestion CODcr (ppm) 4,100 7,800 13,770 20,000 Treated water CODcr (ppm) 533 624 1,377 1,400 CODcr treatment rate (ppm) 87 92 90 93 Batch Reactor CODcr (ppm) 533 624 1,377 1,400 Treated water CODcr (ppm) 85 87 248 210 CODcr treatment rate (ppm) 84 86 82 85 Enemies T-N (Total Nitrogen) 42 148 490 700 Treated Water T-N (Total Nitrogen) 3.8 15 54 63 T-N throughput rate (%) 91 90 89 91 Aeration tank CODcr (ppm) 85 87 248 210 Treated water CODcr (ppm) - - 35 32 CODcr treatment rate (ppm) - - 86 85 Enemies T-N (Total Nitrogen) - - 54 63 Treated Water T-N (Total Nitrogen) - - 31 35 T-N throughput rate (%) - - 42 44 Coagulation precipitation CODcr (ppm) 85 87 35 32 Treated water CODcr (ppm) 66 66 28 25 CODcr treatment rate (ppm) 22 24 20 21 Sand filtration CODcr (ppm) 66 66 28 25 Treated water CODcr (ppm) 58 57 25 22 CODcr treatment rate (ppm) 12 13 10 11 Activated Carbon Filtration CODcr (ppm) 58 57 25 22 Treated water CODcr (ppm) 44 42 19 17 CODcr treatment rate (ppm) 25 27 24 25 Treated water COD _Mn (ppm) 7 6 3 3

Comparative Example 1

The high rate anaerobic digester was operated using pretreated leachate. The operating conditions of the anaerobic digester were the same as in Example 1, and the treatment time was the same as 2 days. The results are shown in Table 5 below.

Days of measurement 10 days 30 days 50 days 60 days Raw water COD _cr (ppm) 4,000 8,000 14,000 20,000 Treated water COD _cr (ppm) 1,320 2,800 4,060 6,200 COD _cr throughput (ppm) 67 65 71 69

The sanitary landfill leachate treatment process of the present invention can reduce suspended solids and hardly decomposable substances from the leachate raw water by the pretreatment process with iron salt, thereby having a good effect on the operation of the anaerobic digester, and treating by using high rate anaerobic digestion species. Not only can you save time, you can even lower the capacity of your anaerobic digester.

In addition, the finally treated water has the effect of satisfying the usual COD _cr 30ppm or less, COD _Mn 10ppm or less.

Claims (2)

Method of treating sanitary landfill leachate consisting of the step of neutralizing the raw leachate from the pre-treatment tank, and then neutralizing it, adding a polymer flocculant to mix and flocculate the flocculant, and then biologically treating the flocculant treated, filtered and discharged. To Neutralizing the iron salt by adding 500 to 6,000 ppm to the leachate, and pretreating the polymer by adding a polymer flocculant; Treating the flocculated water using a high rate anaerobic digester; Passing a batch reactor to remove nitrogen and phosphorus contained in the leachate; Performing a conventional activated sludge process in an aeration tank to remove organic carbon contaminants by biological treatment; And coagulating the treated water flowing out of the aeration tank, and performing sand filtration and activated carbon filtration to reduce organic carbon chloride and suspended solids, and then discharging the treated water with COD _Cr 30 ppm or less and COD _Mn 10 ppm or less. Sanitary landfill leachate treatment method characterized by the above-mentioned. The method of claim 1, wherein the anaerobic digestion treatment is to use a high rate anaerobic digester.

Images