【摘要】：松花江綜合整治是恢復(fù)松花江水環(huán)境的重要手段,而其沿岸污水處理廠設(shè)計與建設(shè)承擔重要的點源污染物的削減工作,其中二沉池作為污水處理廠的一個重要構(gòu)筑物,它制約著最終處理效果。針對于此,本課題在“十二·五”國家科技重大專項子課題“馬家溝城鎮(zhèn)污水深度減排技術(shù)集成與工程示范”的支撐下,開展基于CFD的寒區(qū)輻流式二沉池研究工作,研究寒區(qū)輻流二沉池數(shù)學模型建立以及通過對模擬中結(jié)構(gòu)參數(shù)優(yōu)化和實際運行參數(shù)變化對沉淀的影響,為本“十二·五”示范工程建設(shè)提供高效可靠的技術(shù)參數(shù),改善二沉池流態(tài),解決二沉池占地面積大,流態(tài)不均勻所導(dǎo)致的固液分離效果不佳的問題,從而保障實際污水處理廠的二沉池運行效果。本文以哈市某污水廠輻流式二沉池為模擬對象,利用計算流體力學對其速度場和濃度場進行數(shù)學建模。哈市冬季污水水溫常低于10℃,模擬中對粘度的選擇取10℃時水的粘度1.3077×103Pa?s。通過分析采用RNG的k-?兩方程紊流模型和Mixture多相流模型,分別對池內(nèi)的水流速度場和懸浮物濃度場進行了模擬,以Wells對實際運行的沉淀池試驗結(jié)果為基礎(chǔ),對比驗證了建模中各模型的準確性和合理性,確定了模擬得到的速度場和濃度場與實際情況符合,分析發(fā)現(xiàn)該二沉池存在明顯的異重流和回流現(xiàn)象,池中水流流態(tài)分布很不均勻。利用已確定的建模方式對該二沉池不同結(jié)構(gòu)參數(shù)的各工況點進行模擬,主要結(jié)構(gòu)參數(shù)包括進水導(dǎo)流筒、出水口和本文提出的一種擾流板形式。經(jīng)過分析提出了二沉池結(jié)構(gòu)設(shè)計參數(shù)優(yōu)化方案,確定了導(dǎo)流筒淹沒深度與二沉池中心高度比應(yīng)控制在0.50~0.58,導(dǎo)流筒半徑與二沉池半徑比控制在0.065~0.069,出水設(shè)置為內(nèi)置雙側(cè)堰,位置控制在距池壁2.0m。確定本文提出的水平式擾流板為減輕進水異重流現(xiàn)象和回流區(qū)面積的一種手段,確定擾流板距導(dǎo)流筒最佳垂直距離與池深比控制在0.17。利用已確定的建模方式對結(jié)構(gòu)形式優(yōu)化完畢的二沉池不同運行參數(shù)的各工況點進行模擬,主要運行參數(shù)包括進口流速、懸浮顆粒濃度和懸浮固體顆粒粒徑、密度。確定進口流速0.10m/s為該二沉池最佳運行工況,確定在可實現(xiàn)范圍內(nèi)懸浮物濃度越小,懸浮固體顆粒粒徑、密度越大,對沉淀影響越為有利,提出以投加絮凝劑等方式人為提高懸浮固體顆粒粒徑、密度可以提高二沉池運行效率。通過工程局部經(jīng)濟分析比較,研究所提供的技術(shù)參數(shù)節(jié)省占地33.3%,節(jié)省二沉池總投資29.5%,可以減輕寒冷地區(qū)輻流式二沉池進水異重流和池中回流現(xiàn)象,提高二沉池的運行效率,可為污水廠高效運行、松花江水質(zhì)改善提供技術(shù)支撐,既對污水達標排放、污水廠實現(xiàn)節(jié)能減排要求有重大意義,又與居民的生活緊密聯(lián)系,對我國建設(shè)環(huán)境友好型社會有深遠的意義。
[Abstract]:The comprehensive regulation of the Songhua River is an important means to restore the water environment of the Songhua River, and the design and construction of the sewerage treatment plant along its coast bear the important work of reducing the point source pollutants, among which the secondary settling tank is an important structure of the sewage treatment plant. It restricts the final processing effect. In view of this, under the support of the "12th Five-Year Plan" national important science and technology project, "Technology Integration and Engineering demonstration of Deep sewage Emission reduction in Majiagou Town", the research work of secondary sedimentation tank in cold region based on CFD is carried out. This paper studies the establishment of mathematical model of radial flow secondary settling tank in cold region and the influence of structural parameter optimization and actual operation parameter change on sedimentation in the simulation, which provides efficient and reliable technical parameters for the construction of the "twelfth five year" demonstration project. In order to improve the flow state of the secondary settling tank and solve the problem of poor solid-liquid separation caused by the large area and uneven flow state, the operation effect of the secondary sedimentation tank in the actual sewage treatment plant can be guaranteed. In this paper, the velocity field and concentration field of secondary sedimentation tank of radial flow in a wastewater treatment plant in Harbin city were modeled by computational fluid dynamics. The water temperature of wastewater is usually lower than 10 鈩，

本文編號：2377517