發(fā)布時間：2018-02-26 05:13

  本文關(guān)鍵詞： 揮發(fā)性硅氧烷 恒水位序批式活性污泥法 逸度模型 質(zhì)量流量 生態(tài)風(fēng)險評估　出處：《大連海事大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本文主要對恒水位序批式活性污泥法(CWSBR)為核心工藝的廢水處理廠中的環(huán)狀和線性揮發(fā)性甲基硅氧烷(VMSs)遷移、分布的歸趨變化展開研究,并對其出水水質(zhì)的生態(tài)風(fēng)險進行評估。我們采集一周時間內(nèi)的廢水處理廠進水、出水和污泥樣品,實驗測得其環(huán)狀VMS的平均濃度分別為1.053 μg L-1和0.343μg L-1,總?cè)コ蕿?7.4%。由于較高的固-水分配系數(shù)(Kd),使得污泥樣中的VMSs濃度較高,平均值為4.876 μg g-1。并計算得到該廢水處理廠的每日質(zhì)量流量較穩(wěn)定,周末和工作日的流量及濃度對比均表現(xiàn)為波動不大,在廢水處理廠服務(wù)范圍內(nèi),總VMSs的預(yù)計人均質(zhì)量負(fù)荷為每1000人口145-236 mg d-1,平均為195 mg d-1。為了進一步闡明VMSs的去除機制,建立CWSBR逸度模型來模擬典型環(huán)狀VMS八甲基環(huán)四硅氧烷(D4)、十甲基環(huán)戊硅氧烷(D5)和十二甲基環(huán)己硅氧烷(D6)的去除途徑。模型結(jié)果得69%的D4、24%的D5和9%的D6通過曝氣反應(yīng)和表面揮發(fā)進入到大氣中,其中曝氣是一個主要的方式；而另外17%的D4、45%的D5和54%的D6則吸附至剩余污泥中。綜合實驗和模型結(jié)果表明,污泥吸附和揮發(fā)是影響VMS在該恒水位序批式活性污泥法市政廢水處理廠中歸趨變化的關(guān)鍵因素,隨著環(huán)狀VMS分子量的增大和疏水性的增強,污泥吸附能力逐漸增強而揮發(fā)性則下降。采用蒙特卡洛模擬進行不確定性分析和敏感性分析,得出出水總懸浮固體濃度、混合液相懸浮固體濃度、剩余污泥流量和進水流速是對VMSs質(zhì)量分布影響最大的因素。同時實驗結(jié)果可能會受到居民護膚品和化妝品使用習(xí)慣的周期性模式影響,需要長期對廢水處理廠進行監(jiān)測以獲得數(shù)據(jù)支持。生態(tài)風(fēng)險評估表明,該CWSBR市政廢水處理廠排放的含有D4、D5和D6的出水風(fēng)險商在0.1≤HQ0.5間,未對周圍水生生態(tài)系統(tǒng)構(gòu)成危害,但仍需要進行不定期動態(tài)監(jiān)測,減少高危害、高風(fēng)險發(fā)生的幾率。
[Abstract]:In this paper, the migration and distribution of cyclic and linear volatile methyl siloxane (VMSs) in a wastewater treatment plant with constant water level sequential batch activated sludge process (CWSBR) as the core process were studied. And to assess the ecological risk of the effluent quality. We collected the influent, effluent and sludge samples from the wastewater treatment plant within one week. The average concentrations of cyclic VMS were 1.053 渭 g L-1 and 0.343 渭 g L-1, respectively, and the total removal efficiency was 67.4%. Because of the high solid-water partition coefficient (KDX), the concentration of VMSs in sludge samples was higher. The average value was 4.876 渭 g g-1.The results showed that the daily mass flow of the wastewater treatment plant was stable, and the flow and concentration of the wastewater treatment plant fluctuated little on weekends and weekdays, and were within the service range of the wastewater treatment plant. The estimated per capita mass load of total VMSs is 145-236 mg d-1 per 1,000 population, with an average of 195mg d-1.In order to further clarify the mechanism of VMSs removal, CWSBR fugacity model was established to simulate the removal pathways of typical cyclic VMS octamethylcyclotetrasiloxane (D4), decamethylcyclopentylsiloxane (D5) and 12 methylcyclohexane siloxane (D6). The results of the model showed that 69% of D424% of D5 and 9% of D6 were subjected to aeration reaction. And surface volatilization into the atmosphere, Aeration is one of the main methods, while the other 17% D4N 45% D5 and 54% D6 are adsorbed to the excess sludge. Sludge adsorption and volatilization are the key factors that affect the fate of VMS in the municipal wastewater treatment plant with constant water level sequencing activated sludge process. With the increase of molecular weight and hydrophobicity of cyclic VMS, the adsorption and volatilization of sludge are the key factors. The adsorption capacity of sludge increased gradually but the volatility decreased. The uncertainty analysis and sensitivity analysis of Monte Carlo simulation were used to obtain the total suspended solid concentration of effluent and the concentration of mixed liquid suspension solid. Excess sludge flow and influent flow rate were the most important factors affecting the quality distribution of VMSs. Meanwhile, the experimental results may be influenced by the periodic patterns of skin care products and cosmetics usage habits. Long-term monitoring of wastewater treatment plants is required to obtain data support. The ecological risk assessment shows that the effluent risk quotient containing D4N D5 and D6 discharged from the CWSBR municipal wastewater treatment plant is 0.1 鈮，

本文編號：1536641