滤料Filtermedia滤层内杂质分布规律Impurit

滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer由于反冲洗的水力筛选作用，造成沿滤层深度方向滤料粒径逐渐增大,

Duetothehydraulicscreeningeffectofbackwashing,theparticlesizeofthefiltermediagraduallyincreasesalongthedepthofthefilterlayer;表层滤料粒径小，孔隙率最小，吸附表面积最大；

Theparticlesizeofthesurfacefiltermediaissmall,theporosityisminimum,andtheadsorptionsurfaceareaismaximum;下层滤料粒径大，孔隙率大，吸附表面积小。

Thelowerfiltermediahaslargeparticlesize,largeporosityandsmalladsorptionsurfacearea.细

Fine粗

Coarse滤层含污量（g/cm2）

Filterlayerdirtcontent(g/cm2)单层滤料

Singlelayerfiltermedia石英砂

Quartzsand滤料深度

Filterdepth(cm)过滤刚开始,滤层比较干净，孔隙率较大，孔隙流速小，水力冲刷作用小，大量杂质被表层5-10cm厚度的滤料所截留，少量杂质因粘附不牢而下移，并被下层滤料所截留。

Atthebeginningoffiltration,thefilterlayerisrelativelyclean,withlargeporosity,smallporevelocityandsmallhydraulicscouringeffect.Alargenumberofimpuritiesareretainedbythefiltermedia5-10cmthickonthesurfacelayer,andasmallnumberofimpuritiesmovedownduetopooradhesionandareretainedbythelowerfiltermedia.滤层含污量（g/cm2）

Filterlayerdirtcontent(g/cm2)单层滤料

Singlelayerfiltermedia石英砂

Quartzsand滤料深度

Filterdepth(cm)滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer过滤刚开始,滤层比较干净，孔隙率较大，孔隙流速小，水力冲刷作用小，大量杂质被表层5-10cm厚度的滤料所截留，少量杂质因粘附不牢而下移，并被下层滤料所截留。

Atthebeginningoffiltration,thefilterlayerisrelativelyclean,withlargeporosity,smallporevelocityandsmallhydraulicscouringeffect.Alargenumberofimpuritiesareretainedbythefiltermedia5-10cmthickonthesurfacelayer,andasmallnumberofimpuritiesmovedownduetopooradhesionandareretainedbythelowerfiltermedia.滤层含污量（g/cm2）

Filterlayerdirtcontent(g/cm2)单层滤料

Singlelayerfiltermedia石英砂

Quartzsand滤料深度

Filterdepth(cm)滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer滤层含污能力Filterlayerdirtholdingcapacity单位体积滤层中的平均含污量称为“滤层含污能力”，单位g/cm³或kg/m³

Theaveragedirtcontentinafilterlayerperunitvolumeiscalledthe"dirtholdingcapacityofthefilter"(ing/cm3orkg/m3)单层滤料由水分筛分,滤料上细下粗,使得下层滤料含污能力不能充分发挥。

Thesingle-layerfiltermediaissievedbymoisture,andthefiltermediaisfineintheupperlayerandcoarseinthelowerlayer,sothatthedirtholdingcapacityofthelowerfiltermediacannotbefullyrealized.滤层含污量（g/cm2）

Filterlayerdirtcontent(g/cm2)单层滤料

Singlelayerfiltermedia石英砂

Quartzsand滤料深度

Filterdepth(cm)上层：密度小、粒径大的轻质滤料

Upperlayer:lightfiltermediawithsmalldensityandlargeparticlesize下层：密度大、粒径小的重质滤料

Lowerlayer:heavyfiltermediawithlargedensityandsmallparticlesize充分发挥各层滤料的截污能力，提高滤池的过滤效率。

Fullyrealizetheretainingcapacityofeachlayeroffiltermediaandimprovethefiltrationefficiencyofthefilter.滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer下层粗滤料

Lowercoarsefilter过滤水头一定，滤速急剧减小；

Thefiltrationheadisconstantandthefiltrationratedecreasessharply;表层细滤料

Surfacefine

filtermedia滤速一定，水头损失达到限值；

Thefiltrationrateisconstantandtheheadlossreachesthelimit;泥膜破裂，水质恶化。

Themudfilmrupturesandthewaterqualitydeteriorates.滤层中杂质的分布情况：

Distributionofimpuritiesinthefilterlayer:出现泥膜的结果：

Consequencesincaseofmudfilm:滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer滤层截污量：kg/m3

Retainingcapacityoffilterlayer:kg/m3滤层含污能力：一个过滤周期内，平均值

Dirtholdingcapacityoffilterlayer:averagevaluewithinonefilterrun影响杂质分布的因素：

Factorsaffectingimpuritydistribution:进水水质

Quality水温

Temperature滤料粒径

Particlesize形状和级配

Shapeandgradation滤速

Filtering

rate凝聚颗粒强度

Strength衡量滤料层截留杂质能力的指标：

Indicatorstomeasuretheimpuritiesretainingcapacityofthefiltermedialayer:滤料

Filtermedia滤层内杂质分布规律

ImpurityDistributionPatterninFilterLayer滤速

Filtrationrate滤速越大，水流的冲刷作用也大，杂质在滤层中的穿透深度越大，杂质在整个滤层中的分布越均匀。

Thegreaterthefiltrationrateis,thegreaterthescouringeffectofwaterflowis,thegreaterthepenetrationdepthofimpuritiesinthefilterlayeris,andthemoreuniformthedistributionofimpuritiesinthewholefilterlayeris.滤料粒径及级配的影响

Influenceofparticlesizeandgradationoffiltermedia滤料组成的影响

Influenceofmediacomposition滤料粒径越大,粒径越均匀,孔隙率越大,杂质的穿透深度增加，水头损失增加缓慢，延长工作周期且能提高截污。

Thelargertheparticlesizeofthefiltermediais,themoreuniformtheparticlesizeis,thelargertheporosityis,thegreaterthepenetrationdepthofimpuritiesis,thelowertheheadlossgrowthis,thelongertheworkingperiodisandthebettertheretainingcapacityis.滤层组成的改变，改变了单层级配滤料层中杂质的分布状况，提高了滤层含污能力,降低了滤层中水头损失的增长速率。

Thechangeofthecompositionofthefilterlayerwillchangethedistributionofimpuritiesinthesingle-layergradedfiltermedialayer,improvethedirtholdingcapacityofthefilterlayerandreducesthegrowthrateofheadlossinthefilterlayer.滤料

Filtermedia滤池过滤效率提高的途径

MeanstoImproveFiltrationEfficiencyofFilter尽量使杂质在滤层中均匀分布，采用“反粒度”过滤方式。

Impuritiesshallbeevenlydistributedinthefilterlayerasfaraspossible,andthe"reversegrain"filtrationmodeshallbeadopted.提高滤层含污能力的根本途径：

Thebasicsolutiontoimprovethedirtholdingcapacityofthefilterlayer:双层滤料

Double-layer三层滤料

Three-layer均质滤料

Homogeneous石英砂

Quartzsand石英砂

Quartzsand无烟煤

Anthraciticcoal无烟煤