JP3676397B2

JP3676397B2 - Waste water treatment equipment in landfills

Info

Publication number: JP3676397B2
Application number: JP17689294A
Authority: JP
Inventors: 聡岡崎
Original assignee: 富士エンジニアリング株式会社
Priority date: 1994-07-28
Filing date: 1994-07-28
Publication date: 2005-07-27
Anticipated expiration: 2020-07-27
Also published as: JPH0839076A

Description

【０００１】
【産業上の利用分野】
本発明は、埋立て地における余水処理装置に係り、詳しくはポンプ浚渫船により浚渫された土砂を埋立て地まで排砂管で強制的に流体移送すると共に、埋立て地や沈殿池等において土砂と上水とに分離せしめて、その上水を余水として沈殿池を通して海域へ放流する際、その余水中のＳＳ濃度（浮遊物質濃度）が公害防止水質汚濁防止法において定められている各地域の放流基準値、例えば日平均で 150mg/l（ppm ）、最大で 200mg/l（ppm ）を超えない様にそれを自動管理する余水処理装置に関するものである。
【０００２】
【従来の技術】
従来、この種埋立て地における余水処理は日４回程度のバッチ測定にて行っていた。即ち土砂と分離された上水を余水として海域へと放流される余水の放流基準ＳＳ（浮遊物質濃度）のＳＳ濃度測定はバッチ測定にて日４回程度、作業者が行い、その測定結果に基づいて凝集剤注薬装置からの凝集剤の注薬量を設定し、海域へと放流される余水のＳＳ濃度が放流基準値を超えない様にその管理を行っていた。
【０００３】
【発明が解決しようとする課題】
しかし乍ら、従来の余水処理では作業者によるバッチ測定が行われる以外の間においては凝集剤注薬装置からの注薬量は常に一定であることから、ポンプ浚渫船により浚渫されて埋立て地等の土砂処分場に排砂管で流体移送されてくる揚泥水濃度の変化に対応することができない。即ち、揚泥水濃度は工事地域における土圧、土質等の浚渫条件によって変化するものである。そのために、従来では放流基準値を超えた環境汚染を招く余水がそのまま海域へと放流されてしまう事が多発し、余水のＳＳ濃度が放流基準値を超えない様にそれを管理する余水処理装置として望ましいものではなかった。又、従来では余水処理装置を24時間乃至数日間フルに稼働させるためには上記揚泥水濃度の変化を見込んで凝集剤の注薬量を大目に設定、即ち自然環境に影響を及ぼさない（環境汚染を防ぐ）安全側に注薬量を設定する必要があることから、凝集剤の無駄が多く、コスト高になる。従って、従来ではコストや安全性の面から数日間乃至数週間のフル稼働（無人稼働）は望めない等の実用性に乏しいの余水処理装置であった。
【０００４】
本発明はこの様な従来事情に鑑みてなされたもので、排砂管内を流体移送される揚泥水の濃度測定を連続的に行いながら、その測定結果に応じた凝集剤量にて管直入注薬を自動的に行い得る様にして、海域へと放流される余水ＳＳ濃度が放流基準値を超えない安全性のもとで数日間乃至数週間のフル稼働（無人稼働）を可能にした余水処理装置を提供することを目的とする。
【０００５】
【課題を達成するための手段】
上記目的を達成するために本発明が講じる技術的手段は、浚渫区域から浚渫された揚泥水を排砂管にて埋立て地等の土砂処分場へと流体移送すると共に、その移送途中で排砂管内に土砂の沈降を促進する凝集剤を注薬し、土砂処理場における土砂の沈降により同土砂から分離された上水を余水として沈殿池を通して海域へと放流する余水処理装置であって、排砂管の配管途中にその上流から下流に向けて分岐連絡させたバイパス管を取り付けると共に、同バイパス管の外側には同管内を流体移送される揚泥水濃度を測定する揚泥水濃度計を設置して、前記排砂管内を流体移送される揚泥水濃度を非接触にて測定する様に構成した事を要旨とする。
又、上記揚泥水濃度計がγ線式濃度計であり、同濃度計を設置するバイパス管の内径を 350φmm以内とした事を要旨とする。
【０００６】
【作用】
而して、上記した本発明の請求項１に記載の技術的手段によれば、排砂管内を流体移送される揚泥水の濃度を、同排砂管に分岐連絡させたバイパス管に設置した揚泥水濃度計にて測定する様にしてなることから、揚泥水との接触による損傷がない。それにより、揚泥水濃度の測定を連続的に行う事ができ。
【０００７】
又、バイパス管の内径を 350φmm以内に抑えた事で、揚泥水濃度を測定するγ線式濃度計の放射線レベルは微量で済む。それにより、放射線障害防止法で定められている放射線取扱技術者等の免許（資格）を必要とせずに取り扱うことができる。
【０００８】
【実施例】
本発明の実施の一例を図面に基づいて以下説明すると、図１は余水処理装置の一例を示した配置概略図で、１はポンプ浚渫船により浚渫区域から浚渫された揚泥水を埋立て地２まで流体移送する排砂管、３、４は同排砂管１の配管途中に設置され、同管１内を流体移送される揚泥水の濃度を測定する揚泥水濃度計とその流量を測定する揚泥水流量計、５は揚泥水濃度計３と流量計４から送られてくる測定データから排砂管１内に管直入する凝縮剤の注薬量を算出設定するコントローラ部、６はこのコントローラ部５からの信号により前記排砂管１内に凝集剤を注薬する管直入注薬装置、７は埋立て地２の一部に設けられている沈殿池８への余水放出口９（以下、１次余水吐と称する）近傍に設置され、同１次余水吐９から沈殿池８にオーバフローにて流出する余水のＳＳ濃度（浮遊物質濃度）を測定する１次余水濃度計、10はこの１次余水濃度計７から送られてくる測定データに基づく前記コントローラ部５からの信号により前記１次余水吐９において凝集剤をシャワー添加するシャワー添加装置であり、前記揚泥水濃度計３と１次余水濃度計７との２カ所において連続的に濃度を測定しながら、その測定データに応じて凝集剤の管直入注薬量及びシャワー添加量を可変せしめながら海域へと放流される余水のＳＳ濃度が放流基準値を超えない様に自動的にコントロールする様に構成してある。
【０００９】
排砂管１は、適宜の太さを有する周知の銅管であり、埋立て地２に近いその揚泥水出口側に揚泥水濃度計３とその流量計４とを設置する。
【００１０】
揚泥水濃度計３は、排砂管１内を流体移送される揚泥水の濃度を放射線にて連続的に測定し、その測定データをコントローラ部５に、付図示のアラログ／デジタル変換器を介して送る働きを成すγ線式濃度計であり、排砂管１にその上流から下流に向けて分岐連絡させて取り付けたバイパス管11の外側にγ線式濃度計を取り付けて、非接触にて揚泥水濃度を測定し得る様に構成してある。
【００１１】
バイパス管11は、図２に示した様に排砂管１の一部を適宜の開口大きさと長さにて管内方に向けて凹ませて、その凹部12の上流側壁面12-1と下流側壁面12-2とに亘り貫通状に配管連通せしめて構成し、その外側に図示の如く揚泥水濃度計３を設置する。このバイパス管11の内径は放射線障害防止法で定められている放射線取扱技術者等の免許（資格）を必要とせずに取り扱うことができる様に、即ち微量な放射線レベルにてバイパス管11内を通る揚泥水濃度を測定し得る様に 350φmm以内に抑える。又、このバイパス管11への入り口側即ち凹部12の上流側壁面12-1を適宜の角度θにて下流側に向けて傾斜せしめて、揚泥水の移送を乱すことなく、その一部が速かにバイパス管11に流入せしめる様にしてある。
【００１２】
他方揚泥水流量計４は、排砂管１内を流体移送される揚泥水の濃度を超音波にて連続的に測定し、その測定データをコントローラ部５に、付図示のアラログ／デジタル変換器を介して送る働きを成すドップラー流量計である。
【００１３】
菅直入注薬装置６は、コントローラー部５から出力される注薬量にて排砂管１に揚泥水中に混じり込んでいる土砂の沈降を促進する凝集剤を排砂管１に注薬するものである。
【００１４】
シャワー添加装置10は、埋立て地２と沈殿池８とを連絡する１次余水吐９において、コントローラー部５から出力される注薬量にて凝集剤をシャワー添加するものである。
【００１５】
次に、以上の如く構成した本実施例余水処理装置の動作フローについて簡単に説明すると、まず始めに埋立て地２の残水面積をコントローラ部５にて算出する（工事進捗率に応じて０〜 100％）。然る後、揚泥水濃度計３とその流量計４から送られてくる信号データから排砂管１内への管直入注薬装置６の注薬ポンプ 6-1 による凝集剤の注薬量を設定するために同信号データからコントローラ部５にてＳＳ除去率を後述する算出式から算出する。次に１次余水吐９の１余水濃度計７から送られてくる信号データから１次余水濃度が放流基準値に近い値を示した否かを判断して、１次余水濃度が放流基準値から掛け離れた値が出た場合には注薬ポンプ6-1 による凝集剤の注薬量を自動的に変更する様にしてある。そして、１余水濃度計７から送られてきた信号データにより得られた１次余水濃度から１次余水吐９におけるシャワー添加装置10のシャワーポンプ10-1による凝集剤の添加量を設定するためにコントローラ部５にて沈殿池８における土砂の沈降速度を算出して、１次余水吐９における凝集剤のシャワー添加量を設定する様にしてある。最後に、放流基準値まで処理された余水は２次余水濃度計13が設置されている沈殿池２の２次余水吐14から海域へと放流させる様にしてある。
【００１６】
埋立て地２におけるＳＳ除去率の算出式は次の通りである。
【数１】

ここにＲ：沈殿除去率
ｎ：池の混合の程度を示す定数
Ｖ：粒子の沈降速度（ｍ/s）
Ｑ：流量（ｍ³/s）
Ａ：沈殿池の残水面積（ｍ²）
Ｑ／Ａ：水面積負荷（ｍ/s）
である。
【００１７】
ちなみに、本実施例においては１次，２次余水濃度計７，13として余水の濁り状態を測定する濁度計を採用してなる。
【００１８】
図４はバイパス管11の配管形態を変えた他の実施例を示し、斯る実施例におけるバイパス管11-1は図示の様に、排砂管１の上流側から下流側に向けて外部を通して貫通状に取り付けて、その外側に揚泥水濃度計３であるγ線式濃度計を設置してなるものである。
【００１９】
【発明の効果】
本発明の余水処理装置は叙上の如く構成してなるから、下記の作用効果を奏する。
▲１▼．排砂管内を流体移送される揚泥水の濃度を、同排砂管に分岐連絡させたバイパス管に設置した揚泥水濃度計にて測定する様にしてなることから、揚泥水との接触による損傷がなく、揚泥水濃度の測定を連続的に行う事ができ。
▲２▼．バイパス管の内径を 350φmm以内に抑えた事で、揚泥水濃度を測定するγ線式濃度計の放射線レベルは微量で済む。
【００２０】
従って、本発明の余水処理装置によれば、排砂管内を流体移送される揚泥水の濃度測定を連続的に行いながら、その測定結果に応じた凝集剤量にて管直入注薬を自動的に行い得る様にして、海域へと放流される余水ＳＳ濃度が放流基準値を超えない安全性のもとで数日間のフル稼働（無人稼働）を可能になる。しかも、放射線障害防止法で定められている放射線取扱技術者等の免許（資格）を必要とせずに取り扱うことができることから、誰でも制約を受けること無く取り扱う事ができる。
【図面の簡単な説明】
【図１】本発明の余水処理装置の一例を示した配置概略図
【図２】バイパス管の取り付け部位を拡大して示した断面図
【図３】図２の III−III 線に添わせた縦断面図
【図４】バイパス管の他の実施例を示した同断面図
【符号の説明】
１…排砂管２…埋立て地
３…様泥水濃度計（γ線式濃度計）４…揚泥水流量計（ドップラー流量計）
６…凝集剤の管直入注薬装置 10…凝集剤のシャワー添加装置
11，11-1…バイパス管[0001]
[Industrial application fields]
The present invention relates to a sewage treatment apparatus in a landfill, and more particularly, the soil dredged by a pump dredger is forcibly fluid-transferred to a landfill through a sand discharge pipe, and the earth and sand in a landfill or a sedimentation basin is used. Each area where the SS concentration (floating matter concentration) in the sewage is defined in the Pollution Control Water Pollution Control Law when the sewage is separated into water and discharged into the sea through the sedimentation basin as sewage. It is related to the sewage treatment equipment that automatically manages the discharge standard values of the wastewater, for example, 150 mg / l (ppm) on a daily average and 200 mg / l (ppm) at maximum.
[0002]
[Prior art]
Conventionally, the remaining water treatment in the seed landfill has been performed by batch measurement about four times a day. In other words, the SS concentration measurement of the sewage discharge standard SS (floating matter concentration) that is discharged into the sea area using the water separated from the earth and sand as surplus water is performed about 4 times a day by batch measurement. Based on the results, the amount of flocculant injected from the flocculant injection device was set, and management was performed so that the SS concentration of residual water discharged into the sea area did not exceed the discharge standard value.
[0003]
[Problems to be solved by the invention]
However, in conventional sewage treatment, the amount of injection from the flocculant injection device is always constant during the period other than when batch measurement is performed by the operator. It is not possible to cope with the change in the concentration of pumped muddy water that is fluid transferred to the earth and sand disposal site. That is, the concentration of pumped muddy water changes depending on dredging conditions such as earth pressure and soil quality in the construction area. Therefore, conventionally, surplus water that causes environmental pollution exceeding the discharge standard value is often discharged into the sea area as it is, and there is no need to manage it so that the SS concentration of the surplus water does not exceed the discharge standard value. It was not desirable as a water treatment device. Conventionally, in order to operate the sewage treatment apparatus fully for 24 hours to several days, the amount of flocculant injected is set to be large in consideration of the change in the concentration of the pumped muddy water, that is, it does not affect the natural environment. Since it is necessary to set the injection amount on the safe side (preventing environmental pollution), the coagulant is wasted and the cost is increased. Therefore, in the past, it was a wastewater treatment apparatus with poor practicality such as full operation (unmanned operation) for several days to several weeks could not be expected in terms of cost and safety.
[0004]
The present invention has been made in view of such a conventional situation. While continuously measuring the concentration of the pumped muddy water that is fluid-transferred in the sand discharge pipe, the pipe is directly injected with the amount of the flocculant according to the measurement result. In order to be able to perform medicine automatically, full operation (unmanned operation) for several days to several weeks is possible under the safety that the residual water SS concentration released into the sea area does not exceed the discharge standard value. An object is to provide a wastewater treatment apparatus.
[0005]
[Means for achieving the object]
The technical means taken by the present invention in order to achieve the above object is to transfer the muddy water dredged from the dredged area to a sediment disposal site such as a landfill by means of a sand discharge pipe, and to discharge it during the transfer. It is a wastewater treatment device that dispenses a flocculant that promotes sedimentation into the sand pipe and discharges the water separated from the sediment by sedimentation in the sediment disposal plant into the sea through the sedimentation basin. In addition, a bypass pipe branched and connected from upstream to downstream is installed in the middle of the pipe of the sand discharge pipe, and the concentration of the pumped muddy water is measured outside the bypass pipe to measure the concentration of the pumped muddy water. The gist of the present invention is that the concentration of pumped muddy water that is fluid-transferred in the sand removal pipe is measured in a non-contact manner.
The gist is that the above-mentioned concentration meter is a γ-ray type densitometer, and the inner diameter of the bypass pipe in which the densitometer is installed is set to 350 mm or less.
[0006]
[Operation]
Thus, according to the technical means described in claim 1 of the present invention described above, the concentration of the pumped muddy water that is fluidly transferred in the sand discharge pipe is installed in the bypass pipe branched to the sand discharge pipe. Since it is made to measure with a pumped water concentration meter, there is no damage by contact with pumped water. This makes it possible to continuously measure the concentration of pumped muddy water.
[0007]
In addition, by limiting the inner diameter of the bypass pipe to 350 mm or less, the radiation level of the γ-ray densitometer that measures the concentration of pumped muddy water is very small. Thereby, it is possible to handle without requiring a license (qualification) of a radiation handling engineer or the like defined in the Radiation Hazard Prevention Law.
[0008]
【Example】
An example of the implementation of the present invention will be described below with reference to the drawings. FIG. 1 is an arrangement schematic diagram showing an example of a sewage treatment apparatus, and 1 is a landfill 2 for pumped mud water dredged from a dredging area by a pump dredger.

Drainage pipes

3, 4 and 4 for fluid transfer up to the pipe are installed in the middle of the pipe 1 to measure the concentration of the pumped muddy water and the flow rate thereof. A pumping muddy water flow meter, 5 is a controller unit for calculating and setting the amount of condensing agent to be directly introduced into the sand removal pipe 1 from the measurement data sent from the muddy water concentration meter 3 and the

flow meter

4, and 6 is this controller. A pipe direct injection device 7 for injecting a flocculant into the sand discharge pipe 1 in response to a signal from the unit 5, 7 is a residual water discharge port 9 to a settling basin 8 provided in a part of the landfill 2 ( (Hereinafter referred to as the primary spillway) and overflowed from the primary spillway 9 to the settling basin 8. The primary spillage concentration meter 10 for measuring the SS concentration (floating substance concentration) of the spilled water flowing out from the controller unit 5 based on the measurement data sent from the primary spillage concentration meter 7. A shower addition device for adding a flocculant in the primary spillway 9 by a signal, while continuously measuring the concentration at two locations of the pumped mud concentration meter 3 and the primary spill concentration meter 7, It is configured to automatically control the SS concentration of spilled water discharged into the sea area so that it does not exceed the discharge standard value while varying the amount of flocculant direct injection and shower addition according to the measurement data. It is.
[0009]
The sand discharge pipe 1 is a known copper pipe having an appropriate thickness, and a pumped mud concentration meter 3 and a flow meter 4 are installed on the pumped mud water outlet side near the landfill 2.
[0010]
The pumped muddy water concentration meter 3 continuously measures the concentration of the pumped muddy water that is fluidly transferred through the sand removal pipe 1 with radiation, and the measurement data is sent to the controller unit 5 via an attached analog / digital converter. This is a γ-ray densitometer that works to send it, and attaches a γ-ray densitometer outside the bypass pipe 11 that is branched and connected from the upstream to the downstream of the sand discharge pipe 1, and in a non-contact manner. It is configured to measure the concentration of pumped muddy water.
[0011]
As shown in FIG. 2, the bypass pipe 11 has a part of the sand discharging pipe 1 recessed toward the inside of the pipe with an appropriate opening size and length, and the upstream side wall surface 12-1 of the recess 12 and the downstream side. The pipe is communicated with the side wall surface 12-2 in a penetrating manner, and the pumped muddy water concentration meter 3 is installed outside the pipe as shown in the figure. The inner diameter of this bypass pipe 11 is such that it can be handled without the need for a license (qualification) of a radiation handling engineer etc. stipulated in the Radiation Hazard Prevention Law, that is, the inside of the bypass pipe 11 at a very small radiation level. Keep it within 350mm so that the concentration of pumped muddy water can be measured. In addition, the inlet side to the bypass pipe 11, that is, the upstream side wall surface 12-1 of the concave portion 12 is inclined toward the downstream side at an appropriate angle θ, and a part of the side wall is fast without disturbing the transfer of the pumped mud water. The crab bypass pipe 11 is allowed to flow.
[0012]
On the other hand, the pumped muddy water flow meter 4 continuously measures the concentration of the pumped muddy water that is fluid-transferred in the sand discharge pipe 1 with ultrasonic waves, and the measurement data is sent to the controller unit 5 to the illustrated analog / digital converter. It is a Doppler flowmeter that works to send through
[0013]
The dredging direct injection device 6 injects a flocculant that accelerates sedimentation of the earth and sand mixed in the drainage pipe 1 into the sand discharge pipe 1 with the amount of injection output from the controller unit 5. Is.
[0014]
The shower addition device 10 is for adding a flocculant to the primary surplus water discharge 9 that connects the landfill 2 and the settling basin 8 in the amount of medicine that is output from the controller unit 5.
[0015]
Next, the operation flow of the wastewater treatment apparatus of the present embodiment configured as described above will be briefly described. First, the remaining water area of the landfill 2 is calculated by the controller unit 5 (according to the construction progress rate). 0-100%). After that, from the signal data sent from the pumped muddy water concentration meter 3 and its flow meter 4, the amount of flocculant injected by the injection pump 6-1 of the pipe direct injection device 6 into the sand discharge pipe 1 is determined. In order to set, the SS removal rate is calculated from the same signal data by the controller unit 5 from a calculation formula described later. Next, it is judged from the signal data sent from the primary residual water concentration meter 7 of the primary residual water discharge 9 whether or not the primary residual water concentration shows a value close to the discharge standard value. However, when a value that is far from the discharge reference value appears, the amount of flocculant injected by the injection pump 6-1 is automatically changed. Then, the amount of flocculant added by the shower pump 10-1 of the shower adding device 10 in the primary spillway 9 is set from the primary sewage concentration obtained from the signal data sent from the spillage concentration meter 7. In order to do this, the controller 5 calculates the sedimentation rate of the sediment in the settling basin 8, and sets the shower addition amount of the flocculant in the primary spillway 9. Finally, the sewage treated to the discharge standard value is discharged from the secondary spillway 14 of the settling basin 2 where the secondary spillage concentration meter 13 is installed to the sea area.
[0016]
The formula for calculating the SS removal rate in the landfill 2 is as follows.
[Expression 1]

Where R: precipitation removal rate n: constant indicating the degree of pond mixing V: particle settling velocity (m / s)
Q: Flow rate (m ³ / s)
A: Remaining water area of settling pond (m ² )
Q / A: Water area load (m / s)
It is.
[0017]
Incidentally, in this embodiment, turbidimeters for measuring the turbidity of the sewage are employed as the primary and secondary spillage concentration meters 7 and 13.
[0018]
FIG. 4 shows another embodiment in which the piping configuration of the bypass pipe 11 is changed. In the embodiment, the bypass pipe 11-1 passes through the outside from the upstream side to the downstream side of the sand discharging pipe 1 as shown in the figure. A gamma ray type densitometer which is a pumped mud concentration meter 3 is installed on the outside of the penetrating device.
[0019]
【The invention's effect】
Since the sewage treatment apparatus of the present invention is configured as described above, the following operational effects can be obtained.
(1). Damage due to contact with the pumped mud water is measured because the concentration of the pumped mud water that is transported through the pipe is measured with a pumped mud concentration meter installed in the bypass pipe that is branched and connected to the pipe. There is no, and it is possible to continuously measure the concentration of pumped muddy water.
(2). By limiting the inner diameter of the bypass pipe to 350 mm or less, the radiation level of the γ-ray densitometer that measures the concentration of pumped muddy water is very small.
[0020]
Therefore, according to the sewage treatment apparatus of the present invention, the pipe direct injection is automatically performed with the amount of the flocculant according to the measurement result while continuously measuring the concentration of the pumped muddy water that is fluidly transferred in the sand removal pipe. As a result, the full operation (unmanned operation) for several days becomes possible under the safety that the concentration of residual water SS discharged into the sea area does not exceed the discharge standard value. Moreover, since it can be handled without the need for a license (qualification) of a radiation handling engineer or the like stipulated in the Radiation Hazard Prevention Law, anyone can handle it without any restrictions.
[Brief description of the drawings]
FIG. 1 is a schematic arrangement view showing an example of a sewage treatment apparatus according to the present invention. FIG. 2 is a cross-sectional view showing an enlarged attachment part of a bypass pipe. FIG. 3 is along the line III-III in FIG. Fig. 4 is a sectional view showing another embodiment of the bypass pipe.
DESCRIPTION OF SYMBOLS 1 ... Sand discharge pipe 2 ... Landfill 3 ... Muddy water concentration meter (gamma ray type concentration meter) 4 ... Pumped muddy water flow meter (Doppler flow meter)
6 ... Tube direct injection device for flocculant 10 ... Shower addition device for flocculant
11, 11-1 ... Bypass pipe

Claims

In addition to fluid transfer of dredged water dredged from the dredged area to a landfill site such as a landfill site with a sand discharge pipe, a flocculant that accelerates sedimentation in the sand discharge pipe is injected during the transfer, A sewage treatment device that discharges clean water separated from the sediment by sediment settling in a sewage treatment plant into a sea area through a part of the landslide disposal site or an adjacent sedimentation basin as surplus water,
A bypass pipe that is branched and connected from upstream to downstream is installed in the middle of the pipe of the sand discharge pipe, and a pumped muddy water concentration meter is installed outside the bypass pipe to measure the concentration of the pumped muddy water that is transferred through the pipe. And the residual water treatment apparatus in a landfill characterized by having comprised so that the said muddy water density | concentration may be measured non-contactingly.

The sewage treatment apparatus according to claim 1,
A sewage treatment system for landfills, characterized in that the pumped muddy water concentration meter is a γ-ray type concentration meter and the inner diameter of the bypass pipe where the concentration meter is installed is within 350φmm.