一種污水中砂粒高效采集裝置的設(shè)計(jì)與試驗(yàn)

摘要：污水處理系統(tǒng)中的砂粒含量過(guò)高會(huì)造成設(shè)備磨損等很多負(fù)面影響，而如何對(duì)污水中砂粒含量進(jìn)行快速并有效的檢測(cè)是當(dāng)前的盲區(qū)。本研究設(shè)計(jì)了一種自制連續(xù)流采樣桶，其避免了單一取樣時(shí)步驟繁瑣等缺點(diǎn)，采用連續(xù)采樣方法來(lái)進(jìn)行對(duì)樣品液的大量收集。對(duì)設(shè)計(jì)完成的采樣桶模型進(jìn)行CFD數(shù)值模擬試驗(yàn)，以此來(lái)探究其內(nèi)部的流態(tài)和運(yùn)行效率。試驗(yàn)結(jié)果表明，在進(jìn)水流速為0.1m/s、進(jìn)水砂粒的平均粒徑為0.2mm的情況下，自制連續(xù)流采樣桶對(duì)砂粒的截留效率為94.1%。對(duì)設(shè)計(jì)的采樣桶制造后進(jìn)行現(xiàn)場(chǎng)試驗(yàn)，發(fā)現(xiàn)其對(duì)砂粒的平均截留效率為96.8%。從數(shù)值模擬和現(xiàn)場(chǎng)試驗(yàn)的兩方面結(jié)果來(lái)看，該連續(xù)流采樣桶設(shè)計(jì)合理可靠，運(yùn)行效率高，可用于實(shí)際生產(chǎn)。

關(guān)鍵詞：CFD ; 采樣裝置；砂粒采集；數(shù)值模擬；連續(xù)采樣

中圖分類號(hào)：TU991        文獻(xiàn)標(biāo)識(shí)碼：A      文章編號(hào)：1000-4602（XXXX）XX

Design and testing of an efficient collection device for sand in sewage

Abstract：In wastewater treatment systems，high grit levels can lead to negative effects such as equipment wear and tear, and there is a current blind spot in how to quickly and effectively detect grit levels in wastewater. In this study, a home-made continuous flow sampling bucket was designed, which avoids the disadvantages of tedious steps in single sampling and uses a continuous flow sampling method for the bulk collection of sample liquids. CFD numerical simulations were carried out on the designed sampling bucket model to investigate its internal flow regime and operational efficiency. The test results show that at an inlet flow rate of 0.1m/s and an average particle size of 0.2mm, the home-made continuous flow sampling bucket has a retention efficiency of 94.1%. The designed sampling bucket was manufactured and tested in the field and found to have an average retention efficiency of 96.8% for sand particles. The results from both the numerical simulation and the field test show that the continuous flow sampling bucket has a reasonable and reliable design and operates with high efficiency for practical production.

Key words: CFD；sampling devices；grit collection; numerical simulation; continuous sampling

在污水處理系統(tǒng)中，砂粒會(huì)造成污水停留時(shí)間減小、泵等設(shè)備的磨損^[1]、污泥活性降低、剩余污泥的厭氧消化困難^[2]等危害。除砂系統(tǒng)是砂粒去除的必要單元^[3]，評(píng)估污水廠除砂系統(tǒng)運(yùn)行效率的關(guān)鍵方案就是對(duì)樣品中砂粒含量的有效檢測(cè)，而這前提是實(shí)現(xiàn)對(duì)樣品液的有效收集。

為了保證所得數(shù)據(jù)結(jié)果的準(zhǔn)確性和代表性，需要實(shí)行對(duì)樣品液的大量收集，收集的體積通常在0.5m³以上。可以把污水樣品液的收集方案分成兩大類方法，即一次性取樣方法和連續(xù)采樣方法。一次性取樣方法通常借助水桶等容器直接從水體采集出，相對(duì)方便，但每次采集的體積較少，如果多次采集則費(fèi)時(shí)費(fèi)力，相關(guān)方法在林杰^[4]、董志杰^[5]等人的論文中有所體現(xiàn)。而連續(xù)采樣方法以連續(xù)流采樣桶為代表，該裝置的運(yùn)行原理是讓污水同時(shí)流進(jìn)和流出，在這個(gè)過(guò)程中利用裝置的結(jié)構(gòu)特性實(shí)現(xiàn)對(duì)污水中砂粒的有效截留。這種方法的好處是受到樣品液總量的限制很小，只要截留下的砂粒不充滿裝置底部，理論上可以實(shí)現(xiàn)對(duì)污水長(zhǎng)時(shí)間的連續(xù)采集。

本研究則是以旋流分離設(shè)備為設(shè)計(jì)基礎(chǔ)，利用旋流分離的原理，設(shè)計(jì)出了一種自制連續(xù)流采樣裝置。