JPH10118427A - Filter material for rough filtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the filtering of water containing solid matter having a large particle size, to increase a suspended substance collected during a filtering continuing time and to enhance washing recovery properties by constituting a filter material of low m.p. fibers and high m.p. fibers or composite fibers or the composite fibers and the high m.p. fibers and setting the length thereof to a specific range. SOLUTION: This filter material is constituted of low m.p. fibers and high m.p. fibers or composite fibers or the composite fibers and the high m.p. fibers and the length thereof is set to 60-300mm. When the length is less than 60-300mm, voids necessary for rough filtering become short when the filter materials are laminated within a filter tank and, when the length is larger than 60-300mm, uniform lamination in the filter tank becomes difficult and filtering capacity becomes inferior. Further, it is pref. that the length is set to 100-150mm and the diameter of the cross section of the filter material is set to 10-50mm. By this constitution, a filtering continuing time can be made long and an amt. of a suspended substance collected during this time by the filter material also becomes large and the separability of the collected suspended substance is good and, therefore, the durability of the filter material to repeated use is also enhanced.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、粗大浮遊物質を高
濃度に含む汚水、例えば、降雨直後に下水処理場に流入
する下水（降雨時初期流入下水）などを濾過するために
使用される粗濾過用濾材に関するものである。The present invention relates to a coarse water used for filtering sewage containing a high concentration of coarse suspended substances, for example, sewage flowing into a sewage treatment plant immediately after rainfall (initial inflow sewage during rainfall). The present invention relates to a filter medium for filtration.

【０００２】[0002]

【従来の技術】従来から汚水などを浄化するための濾材
としては、砂、濾紙、濾布、セラミック、不織布、金網
などからなるものが用いられてきたが、これらの濾材は
濾過する液体中の浮遊物質が目詰まりして濾過流速が低
下しやすいため、濾過流速を低くして濾槽の面積を大き
くとる必要があった。2. Description of the Related Art Sand, filter paper, filter cloth, ceramic, non-woven fabric, wire mesh, and the like have conventionally been used as a filter medium for purifying sewage water. Since the suspended solids are clogged and the filtration flow rate tends to decrease, it is necessary to reduce the filtration flow rate and increase the area of the filtration tank.

【０００３】このような欠点を解消するための濾材とし
て、例えば特公昭62-11637号公報に記載されているよう
な繊維を絡み合わせた繊維塊を濾過用濾材として用い、
これを濾槽内に積層し濾過時における浮遊物質の付着効
果の向上を図るというものがある。[0003] As a filter medium for solving such a drawback, for example, a fiber mass in which fibers are entangled as described in JP-B-62-11637 is used as a filter medium for filtration.
There is a method in which this is laminated in a filter tank to improve the effect of adhering suspended substances during filtration.

【０００４】また、特開平7-155519号公報には、熱融着
性繊維を絡み合わせた繊維塊を熱処理して繊維体中の短
繊維同志を融着する方法が示されている。また、特開平
5-329312号公報には、引き揃えた繊維間に多数の点接着
点を形成した棒状繊維集束体を３〜50mmに切断して得ら
れる水処理材が示されている。Japanese Patent Application Laid-Open No. Hei 7-55519 discloses a method of heat treating a fiber mass in which heat fusible fibers are entangled to fuse short fibers in a fibrous body. In addition,
JP-A-5-329312 discloses a water treatment material obtained by cutting a rod-shaped fiber bundle having a large number of point bonding points between aligned fibers into a length of 3 to 50 mm.

【０００５】これらの繊維体を充填した濾過装置によ
り、濾過する水の浮遊物質濃度が 100mg／リットル程度以下
の比較的希薄な汚水、例えば下水処理場で生物処理がな
され、沈殿槽を経た水などを濾過する場合は、繊維塊を
構成する繊維が作る立体的な網目構造が濾過面積を大き
くするため、浮遊物質の保持能力が高く、また砂などに
比べて空隙率が高いため濾過速度も大きくとることが可
能であった。[0005] By using a filtration device filled with these fibrous bodies, relatively dilute sewage having a suspended substance concentration of water to be filtered of about 100 mg / liter or less, such as water that has undergone biological treatment in a sewage treatment plant and has passed through a sedimentation tank. When filtering, the three-dimensional network structure created by the fibers that make up the fiber mass increases the filtration area, so it has a high retention capacity for suspended substances, and also has a high porosity compared to sand, etc., so the filtration speed is high. It was possible to take.

【０００６】一方、雨水と汚水が同時に流れ込む形式の
いわゆる合流式下水処理場においては、降雨初期に下水
の量が急増し、晴天時に管渠内壁に蓄積されていた固形
物が押し流されるため、浮遊物質を1000mg／リットル程度含
み、かつ粒径が５mm以上の粗大な固形物を含む下水が処
理場の許容量を超えて流れ込むことが問題となってお
り、この降雨時初期流入下水に対しても何らかの簡易的
な処理を行なう必要があるとされている。この簡易処理
法の１つとして、濾過によって浮遊物質濃度を 100mg／
リットル以下程度まで低減して放流するという方法が考えら
れているが、従来の繊維濾材による濾過を適用した場合
には、濾過開始後しばらくは清澄な濾過水が得られるも
のの、すぐに濾層が閉塞して圧力損失が急上昇し、頻繁
に逆洗浄を行なわなければならず、そのため、濾過継続
時間中に濾材に捕捉される浮遊物質量が少なくなるとい
う欠点を有していた。また、濾材と下水に含まれる粗大
な固形物の大きさが似通っているため、逆洗浄時に粗大
固形物を濾材と分離するのが困難であった。On the other hand, in a so-called combined sewage treatment plant in which rainwater and sewage flow simultaneously, the amount of sewage increases rapidly in the early stage of rainfall, and the solid matter accumulated on the inner wall of the sewer in clear weather is washed away. It is a problem that sewage containing about 1000 mg / liter of substances and containing coarse solids with a particle size of 5 mm or more flows in excess of the allowable capacity of the treatment plant. It is said that some simple processing needs to be performed. As one of the simple processing methods, the concentration of suspended solids is 100 mg /
It has been considered that the water is discharged to a volume of about 1 liter or less.However, if conventional filtration using a fiber filter material is applied, clear filtered water is obtained for a while after the start of filtration, but the filtration layer is immediately formed. There was a drawback that the pressure loss rapidly increased due to the blockage, and the backwashing had to be performed frequently, so that the amount of suspended solids captured by the filter medium during the continuous filtration time was reduced. In addition, since the size of the coarse solid contained in the filter medium and the sewage is similar, it was difficult to separate the coarse solid from the filter medium at the time of back washing.

【０００７】[0007]

【発明が解決しようとする課題】本発明は、濾過用濾材
として従来の繊維体が備えている濾過速度の大きさを維
持しつつ、上記の問題を解決するためになされたもので
あり、その目的とするところは、濾槽内に積層したとき
の空隙率が高く、降雨時初期流入下水のように浮遊物質
の濃度が1000mg／リットル程度で５mm以上の大粒径の固形物
を含む水を低濾過圧で大量に濾過することが可能であ
り、濾過継続時間中に濾材に捕捉される浮遊物質量が多
く、かつ洗浄回復性に優れた粗濾過用濾材を提供するこ
とにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems while maintaining the filtration speed of a conventional fibrous body as a filter medium for filtration. The objective is to remove water containing large solids of 5 mm or more with a concentration of suspended substances of about 1000 mg / liter, such as sewage at the time of rainfall, which has a high porosity when laminated in a filter tank. It is an object of the present invention to provide a coarse filtration filter medium that can perform a large amount of filtration at a low filtration pressure, has a large amount of suspended matter captured by the filter medium during a continuous filtration time, and has excellent washing recovery properties.

【０００８】[0008]

【課題を解決するための手段】本発明は、上記の課題を
解決するためになされたものであり、低融点繊維と高融
点繊維とで、または低融点部分と高融点部分とを持つ複
合繊維（以下、単に複合繊維という）で、あるいは低融
点部分と高融点部分とを持つ複合繊維と高融点繊維とで
構成され、長さが60〜300mm であることを特徴とする粗
濾過用濾材を要旨とするものである。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a composite fiber having a low melting point fiber and a high melting point fiber or a low melting point portion and a high melting point portion. (Hereinafter simply referred to as composite fiber), or a filter medium for coarse filtration comprising a composite fiber having a low melting point portion and a high melting point portion and a high melting point fiber and having a length of 60 to 300 mm. It is an abstract.

【０００９】[0009]

【発明の実施の形態】以下、本発明の実施の形態につい
て説明する。本発明の濾材は、低融点繊維と高融点繊維
とで、または複合繊維、あるいは複合繊維と高融点繊維
とで構成される。どの組み合わせによる場合において
も、濾材を構成する繊維の低融点箇所の融点は 130℃以
下、軟化点は 100℃以下であることが好ましく、融点が
100℃以下であることがより好ましい。また、高融点箇
所の融点は低融点箇所の融点と30℃以上の差があること
が好ましい。Embodiments of the present invention will be described below. The filter medium of the present invention is composed of a low-melting fiber and a high-melting fiber, or a composite fiber, or a composite fiber and a high-melting fiber. In any case, the low melting point of the fiber constituting the filter medium preferably has a melting point of 130 ° C or lower and a softening point of 100 ° C or lower.
It is more preferable that the temperature is 100 ° C. or lower. The melting point of the high melting point preferably has a difference of 30 ° C. or more from the melting point of the low melting point.

【００１０】低融点繊維あるいは複合繊維を高融点繊維
と組み合わせて濾材を構成する場合は、低融点繊維ある
いは複合繊維の比率を少なくとも30重量％以上、好まし
くは50重量％以上用いることが好ましい。この比率から
外れない限り、低融点繊維、高融点繊維、複合繊維はそ
れぞれ複数種のものを混合して用いることができる。ま
た、各繊維の太さは１〜20デニールのものを用いるのが
好ましい。When a low-melting fiber or a composite fiber is combined with a high-melting fiber to form a filter medium, the ratio of the low-melting fiber or the composite fiber is preferably at least 30% by weight, more preferably at least 50% by weight. As long as the ratio does not deviate from this ratio, a plurality of types of low-melting fibers, high-melting fibers, and conjugate fibers can be mixed and used. Further, it is preferable to use a fiber having a thickness of 1 to 20 denier.

【００１１】低融点繊維としては、イソフタル酸を共重
合したポリエチレンテレフタレート、６−ナイロン、ポ
リエチレン、ポリプロピレンなどから適宜選ぶことがで
きる。高融点繊維としては、ポリエステル、ポリアミ
ド、ポリアクリル、ビニロンなどを用いることができ
る。また、低融点繊維との接着効果があれば天然繊維も
使用可能である。複合繊維としては、低融点のイソフタ
ル酸共重合ポリエステルまたはポリエチレンを鞘部、高
融点のポリエチレンテレフタレートを芯部とする芯鞘
型、あるいは低融点のイソフタル酸共重合ポリエステル
を断面の片側に、もう一方の片側に高融点のポリエチレ
ンテレフタレートを配したサイドバイサイド型などの複
合繊維を用いることができる。The low melting point fiber can be appropriately selected from polyethylene terephthalate copolymerized with isophthalic acid, 6-nylon, polyethylene, polypropylene and the like. As the high melting point fiber, polyester, polyamide, polyacryl, vinylon, or the like can be used. Natural fibers can also be used as long as they have an effect of bonding to low-melting fibers. As the conjugate fiber, a core-sheath type having a low melting point isophthalic acid copolymerized polyester or polyethylene as a sheath, a high melting point polyethylene terephthalate as a core, or a low melting point isophthalic acid copolymerized polyester on one side of a cross section and the other side. A composite fiber such as a side-by-side type in which a high-melting polyethylene terephthalate is disposed on one side can be used.

【００１２】これらの繊維を20mm程度に切断し、紡績用
カード機で開繊しスライバー状とするか、低融点繊維ま
たは複合繊維のみに懸縮をかけたトウ状とし、十分に開
繊された状態の繊維束を得れば良い。この繊維束に濾材
を構成する繊維の低融点箇所の軟化点以上、融点以下
で、かつ融点との温度差が30℃以内である熱風を吹き掛
け、または同温度の雰囲気中を通すことによって、低融
点箇所を軟化させ、繊維間の接点を融着させれぱ良い。
この後、口金に導いて繊維束の直径を一定とし、冷却
後、所定の長さに切断すれば良い。These fibers were cut to about 20 mm and opened with a carding machine for spinning to form slivers, or tows having only low-melting-point fibers or composite fibers crimped, and were sufficiently opened. What is necessary is just to obtain the fiber bundle of a state. By blowing hot air having a softening point of the low-melting point of the fiber constituting the filter medium above the softening point, below the melting point, and a temperature difference from the melting point of the fiber bundle within 30 ° C., or by passing the fiber bundle through an atmosphere at the same temperature, It is good to soften the low melting point and fuse the contact points between the fibers.
Thereafter, the fiber bundle is guided to a die to make the diameter of the fiber bundle constant, and after cooling, it may be cut into a predetermined length.

【００１３】このとき、長さを60〜300mm とするが、こ
れより小さい場合は濾槽内に積層したときに粗濾過に必
要な空隙が確保できず、濾層の閉塞によって濾過継続時
間が短くなり、またこれより大きい場合は濾層内に均一
に積層することが困難となり、濾過性能が悪化すること
になる。また、長さを 100〜 150mm、断面の直径を10〜
50mmとするのが良い。At this time, the length is set to 60 to 300 mm. If the length is smaller than this, a space required for coarse filtration cannot be secured when the filter is laminated in the filter tank, and the filtration continuation time is short due to blockage of the filter layer. On the other hand, if it is larger than this, it is difficult to laminate uniformly in the filter layer, and the filtration performance deteriorates. In addition, the length is 100 ~ 150mm, and the cross section diameter is 10 ~
50mm is good.

【００１４】本発明の濾材により降雨時初期流入下水な
どの濾過を行なう際、重力式あるいは圧力式の下向流に
よる濾過装置では、濾槽の最下部に多孔板を設け、その
上部に濾材を充填して濾過を行なえば良い。また、上向
流式の濾過装置においては、原水流入部よりも上方で、
多孔板により濾材を上下から挟み込む形に支持して濾過
を行なう。When filtering the initial inflow sewage or the like during rainfall with the filter medium of the present invention, a gravity type or pressure type downflow filtration apparatus is provided with a perforated plate at the bottom of a filter tank and a filter medium at the top. What is necessary is just to fill and filter. Also, in the upward flow type filtration device, above the raw water inflow portion,
Filtration is performed by supporting the filter medium between upper and lower sides with a perforated plate.

【００１５】[0015]

【実施例】以下、本発明を実施例により具体的に説明す
る。 実施例１ 芯部をポリエチレンテレフタレート（融点 280℃）、鞘
部をテレフタル酸とイソフタル酸の共重合物（モル比70
／30、融点 190℃）とした繊度15デニール、繊維長25mm
の複合繊維を１ｍ当たり10ｇのカードスライバーとし、
240℃に加熱した空気を直接吹き掛けた後、直径20mmの
円形口金に導入し１ｍ／分の速度で引取ったものを冷却
して 100mmの長さに切断して濾材を得た。The present invention will be described below in more detail with reference to examples. Example 1 The core was polyethylene terephthalate (melting point 280 ° C.), and the sheath was a copolymer of terephthalic acid and isophthalic acid (molar ratio 70).
/ 30, melting point 190 ℃), fineness 15denier, fiber length 25mm
Of the composite fiber of 10g per meter as a card sliver,
After directly blowing air heated to 240 ° C., the mixture was introduced into a circular die having a diameter of 20 mm, taken out at a speed of 1 m / min, cooled and cut into a length of 100 mm to obtain a filter medium.

【００１６】この濾材を直径 500mmの円筒状濾過装置に
２ｍの高さに充填し、Ｋ市下水処理場の降雨時初期流入
下水に対して、濾過速度1000ｍ／日で上方より下降流に
て濾過を行ない、濾過開始から４時間経過後または圧力
損失水頭が１ｍ上昇した時点で濾過終了とした。This filter medium is filled into a cylindrical filtration device having a diameter of 500 mm to a height of 2 m, and is subjected to a downward flow from above at a filtration speed of 1000 m / day against the initial inflow sewage during rainfall at a sewage treatment plant in K City. The filtration was terminated 4 hours after the start of filtration or when the pressure loss head increased by 1 m.

【００１７】１時間毎に濾過原水と濾過水の浮遊物質濃
度を測定し、各回毎に除去率を求めて表１に示した。The concentration of suspended solids in the filtered raw water and the filtered water was measured every hour, and the removal rate was determined each time. The results are shown in Table 1.

【００１８】[0018]

【表１】 [Table 1]

【００１９】圧力損失水頭が１ｍ上昇するまで４時間に
満たない場合は濾過継続時間を、４時間に達した場合は
そのときの圧力損失水頭を測定することとし、表２に示
した。When the pressure drop head rises by 1 m in less than 4 hours, the filtration duration is measured. When the pressure drop reaches 4 hours, the pressure loss head at that time is measured, and the results are shown in Table 2.

【００２０】[0020]

【表２】 [Table 2]

【００２１】濾過終了後、装置下部より空気を吹き込み
濾材を流動させて逆洗浄を行ない、濾材に捕捉された浮
遊物質を剥離させ、逆洗浄排水中の浮遊物質濃度と排水
量から濾材１m³当たりの浮遊物質剥離量を算出し、表２
に示した。[0021] After filtration, subjected to reverse washing in flowing medium blowing air from a lower portion of the apparatus, it is peeled suspended solids captured by the filter medium, the suspended solids concentration in the backwash effluent and wastewater per filter medium 1 m ³ The amount of suspended solids was calculated.
It was shown to.

【００２２】また、濾過終了後濾材の一部を解体して濾
材に捕捉された浮遊物質を全て洗い出す方法で、濾材１
m³当たりの浮遊物質の全捕捉量を算出し、表２に示し
た。また、これら２つの値を用いて、数１により逆洗浄
による浮遊物質の剥離率を求め、表２に示した。Further, after the filtration is completed, a part of the filter medium is dismantled to wash out all the suspended substances trapped in the filter medium.
calculating the total amount of captured suspended solids per m ^3, it is shown in Table 2. In addition, using these two values, the peeling rate of the suspended substances due to the backwashing was calculated by Equation 1 and shown in Table 2.

【００２３】[0023]

【数１】 (Equation 1)

【００２４】実施例２ 実施例１と全く同一条件で、断面の直径が10mmの繊維束
を60mmに切断した濾材を作成し、実施例１と同一の試験
を行なった。 比較例１ 実施例１と全く同じ条件で、直径８mmの繊維束を長さ20
mmに切断した濾材を作成し、実施例１と同一の試験を行
なった。Example 2 Under the same conditions as in Example 1, a filter medium was prepared by cutting a fiber bundle having a sectional diameter of 10 mm into 60 mm, and the same test as in Example 1 was performed. Comparative Example 1 A fiber bundle having a diameter of 8 mm and a length of 20 mm was obtained under the same conditions as in Example 1.
A filter medium cut into mm was prepared, and the same test as in Example 1 was performed.

【００２５】以上の実施例１、２と比較例１との結果よ
り明らかなごとく、原水浮遊物質濃度は実験開始初期に
700mg／リットル程度まで上昇し、１時間後から４時間後に
かけては徐々に減少したが、その間、実施例１で４時間
以上、実施例２においても２時間以上の濾過継続時間が
得られたのに対し、比較例１では１時間以内に圧力損失
が急上昇して濾過の継続が不可能となった。また、実施
例１および２では原水の浮遊物質濃度が高いほど高い除
去率が得られており、高濃度の浮遊物質を含む原水に対
して効果的な濾過が行なえたといえる。As is clear from the results of Examples 1 and 2 and Comparative Example 1, the concentration of suspended solids in the raw water was determined at the beginning of the experiment.
It increased to about 700 mg / liter and gradually decreased from 1 hour to 4 hours. In the meantime, the filtration continuation time of 4 hours or more in Example 1 and 2 hours or more in Example 2 was obtained. On the other hand, in Comparative Example 1, the pressure loss rapidly increased within one hour, and it became impossible to continue the filtration. In Examples 1 and 2, the higher the concentration of suspended solids in the raw water, the higher the removal rate was obtained, and it can be said that effective filtration was performed on the raw water containing the suspended solids with a high concentration.

【００２６】濾材の浮遊物質全捕捉量は実施例１で30kg
／m³−濾材以上、実施例２で20kg／m³−濾材以上と、比
較例１の 7.4kg／m³−濾材に比べて大きな値となってお
り、また、逆洗浄による剥離率でも実施例１、２では70
％以上の値が得られている。The total amount of suspended solids trapped by the filter medium was 30 kg in Example 1.
/ M ³ -filter material or more, 20 kg / m ³ -filter material or more in Example 2, which is larger than that of 7.4 kg / m ³ -filter material of Comparative Example 1, and the peeling rate by back washing was also measured. In Examples 1 and 2, 70
% Or more is obtained.

【００２７】[0027]

【発明の効果】以上のように本発明の粗濾過用濾材は、
積層したときの空隙率が高くて一定であるため、浮遊物
質の濃度が高く、かつ大粒径の固形物を含む汚水などを
高速で濾過する場合に、従来の繊維体のように圧力損失
がすぐに上昇することがないので濾過継続時間を長くと
ることができ、その間に濾材に捕捉される浮遊物質の量
も多く、また捕捉した浮遊物質の分離性が良いため繰り
返し使用に対する耐久性も向上する。As described above, the filter medium for coarse filtration of the present invention is:
Since the porosity is high and constant when stacked, the concentration of suspended solids is high, and when filtering wastewater containing large solids at high speed, pressure loss is reduced as in the case of conventional fibrous bodies. Since it does not rise immediately, the duration of filtration can be extended, while the amount of suspended matter trapped in the filter medium is large, and the separation of the trapped suspended matter is good, improving durability against repeated use. I do.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 低融点繊維と高融点繊維とで、または低
融点部分と高融点部分とを持つ複合繊維で、あるいは低
融点部分と高融点部分とを持つ複合繊維と高融点繊維と
で構成され、長さが60〜300mm であることを特徴とする
粗濾過用濾材。1. A composite fiber comprising a low melting point fiber and a high melting point fiber, a composite fiber having a low melting point part and a high melting point part, or a composite fiber having a low melting point part and a high melting point part and a high melting point fiber. And a length of 60 to 300 mm.