刚性填料布置方式对水流特性及污染物去除的影响

On the impacts of the ditch flow currency on the pollutant removal due to the different allocations of the rigid bio-ecological stuffs

研究使用生物填料技术净化河流水体对水流特性的影响,生物填料分为刚性和柔性两种,采用刚性生物填料进行试验。对室内大小相同的填料渠(长×宽×高为1 000 cm×40 cm×30 cm)设置不同的填料密度和布置方式:A渠填料密度为48 m/m3,均匀填充;B渠为24 m/m3,均匀填充;C渠为24 m/m3,两边填充;D渠为空白。在不同的水力停留时间(HRT)下,分析各渠x和y方向流速等值线图及COD去除率。结果表明:1)由于不同水渠填料布置方式不同,其流态也存在差异,流场紊乱程度从高到低的填料渠为C渠、A渠、B渠、D渠;2)填充密度和布置方式对填料与水体的接触也有影响,水体通过填料层流量占总流量百分比从大到小的各渠为C渠、B渠、A渠,随HRT增加差距缩小;3)填料填充密度越大,对COD的去除率越高,同等密度下,填料两边布置比均匀布置对COD有更好的去除效果。

This paper is aimed at introducing the study results of the impacts of the water flow characteristics on the biological stuffs in sewage purification. The so-called biological stuffs can usually be divided into two kinds： the flexible one and the rigid one. But the staffing material we have adopted in our experiment in this paper belongs to the rigid one. As a matter of fact, the biological stuffs in the ditches are composed of different densities and patterning forms. For example, we have arranged four types of such biological stuffs in dif- ferent lengths, width and heights： in ditch A （48 m/m3 per ditch, equally distributed）, in ditch B （24 m/m3 per ditch, equally dis- tributed/; in ditch C, the similar manner, the density is staggered distributed on the two sides in the form of 24 m/m3 per ditch; in ditch D （blank control） done in the same size （length × width × height： 1 000 cm × 40 cm × 30 cm）. To make it clear, we can analyze the flow field and the velocity contour map as well as the COD removing rate of each ditch in x and y direction under different hydraulic retention times. And, then, we have also studied the re- moval rate of COD for different resulted forms and densities. The re- sults of our analysis can be taken as the reference to the use of the rigid biological stuffs for water purification. The main results of our study can be illustrated as follows ： （ 1 ） The impacts of the biological stuffing patterning forms on the water flow can be different in fea- tures. The flow field disturbance degree can be found decreased in a descending order, such as： ditch C 〉 ditch A 〉 ditch B 〉 ditch D; （2） The contact conditions between the water and the stuffing material for each ditch may vary in the biological stuffing densities and the arrangement forms. In so doing, with the prolonging of the hydraulic retention time, the difference degree can be reduced. The ra- tio of the water flow through the packaging layer of the total water flow has been found decreased in an descending order as foUows： ditch C 〉 ditch B 〉 ditch A. （3） The removal rate of COD can be increased with the increase of the density of biological stuffing. Mean- while, as compared with the equally distributed forms, the removal rate of COD tends to be higher with the staggered distributed forms of biological stuffing under the same layout density.