發(fā)布時間：2019-03-17 18:17

【摘要】：滴灌系統(tǒng)灌水器堵塞問題直接影響灌水均勻度、系統(tǒng)壽命和運(yùn)行效益,已成為制約滴灌技術(shù)應(yīng)用和推廣的關(guān)鍵問題之一。尤其是目前水環(huán)境污染與水資源緊缺并重,滴灌水源復(fù)雜的水質(zhì)特征使得灌水器堵塞風(fēng)險更大、機(jī)理更復(fù)雜,堵塞類型也通常表現(xiàn)為生物堵塞。目前灌水器堵塞問題仍然是困擾滴灌研究領(lǐng)域的國際性難題,其關(guān)鍵在于對堵塞誘發(fā)機(jī)理不明。本文選擇水質(zhì)特征最復(fù)雜、最典型的再生水作為滴灌水源,持續(xù)五年通過污水處理廠滴灌灌水器堵塞現(xiàn)場試驗(yàn)及室內(nèi)滴灌灌水器堵塞模擬試驗(yàn)和精細(xì)測試,系統(tǒng)研究了灌水器生物堵塞發(fā)生特征,提出了灌水器抗堵塞能力快速評估方法；探索了生物堵塞物質(zhì)形成和生長過程及其對灌水器堵塞發(fā)生的影響途徑與誘發(fā)機(jī)理,為滴灌灌水器新產(chǎn)品抗堵塞設(shè)計及滴灌系統(tǒng)安全高效運(yùn)行提供理論支撐。主要研究內(nèi)容與結(jié)論包括：通過灌水器流量長期、高頻測試,確定了兩年運(yùn)行周期內(nèi)其堵塞參數(shù)表現(xiàn)為“波動平衡-啟動線性變化-翌年加速線性變化”變化特征,定量描述了灌水器生物堵塞發(fā)生過程,摸清了再生水水質(zhì)、灌水器類型和流道結(jié)構(gòu)參數(shù)及灌水頻率對灌水器生物堵塞過程的影響�；诠嗨魃锒氯l(fā)生特性,從全新角度提出了灌水器抗堵塞能力評估指數(shù)(Ia),Ia的關(guān)鍵因素包括流道長、寬深比和近壁面平均剪切力,借助量綱分析理論建立了通過灌水器額定流量和流道結(jié)構(gòu)參數(shù)估算Ia的方法,驗(yàn)證了Ia用于快速評估灌水器自身抗堵塞能力的準(zhǔn)確性和可行性。借助現(xiàn)代環(huán)境微生物學(xué)精細(xì)方法測試了灌水器生物堵塞物質(zhì)特征組分,確定了堵塞物質(zhì)特征組分與灌水器堵塞程度間的“S型曲線”相關(guān)關(guān)系(R20.92**,p0.01),灌水器堵塞程度隨著堵塞物質(zhì)組分增長表現(xiàn)出“敏感-微敏感-極度敏感”的趨勢,摸清了堵塞物質(zhì)特征組分形成和生長過程對灌水器堵塞發(fā)生過程的影響途徑。綜合考慮營養(yǎng)物質(zhì)輸送和水力剪切力分布的影響,系統(tǒng)研究了灌水器類型和結(jié)構(gòu)參數(shù)、滴灌毛管不同位置、肥料類型等因素對堵塞物質(zhì)形成和生長過程的影響效應(yīng),提出了各影響因素下的合理控制閾值。以Logistic生長模型為原型,綜合考慮灌水器結(jié)構(gòu)類型、流道幾何參數(shù)以及毛管位置等關(guān)鍵影響因素,建立的堵塞物質(zhì)生長動力學(xué)模型可以很好地描述堵塞物質(zhì)組分“生長適應(yīng)期-快速增長期-動態(tài)穩(wěn)定期”的生長過程(R20.85**,p0.01)。量化了堵塞物質(zhì)中發(fā)揮重要作用的微生物群落的演變特征,確定了灌水器堵塞過程中的關(guān)鍵菌株,深入揭示了灌水器生物堵塞誘發(fā)機(jī)理,提出了合理的灌水器堵塞控制策略。
[Abstract]:The problem of irrigation clogging in drip irrigation system directly affects irrigation uniformity, system life and operation benefit, which has become one of the key problems restricting the application and popularization of drip irrigation technology. Especially at present, water environment pollution and water resources shortage are equally important. The complicated water quality characteristics of drip irrigation make the clogging risk of emitters more serious and the mechanism more complicated, and the blocking types are usually biological clogging. At present, the clogging problem of emitters is still an international problem in the field of drip irrigation, and the key is that the mechanism of clogging is unknown. In this paper, the most complex and typical reclaimed water is selected as the source of drip irrigation, which has passed the field test of drip irrigation emitters clogging in sewage treatment plant, simulation test and fine test of indoor drip irrigation emitters for five years. The characteristics of biological clogging in emitters were systematically studied, and the rapid evaluation method of emitters' anti-clogging ability was put forward. The formation and growth process of biological clogging material and its influence on emitters blockage and its inducing mechanism were explored, which provided theoretical support for the design of new products of drip irrigation emitters against clogging and the safe and efficient operation of drip irrigation system. The main research contents and conclusions are as follows: through the long-term and high-frequency testing of the emitters flow rate, the blocking parameters of the emitters during the two-year operation cycle are determined to be "fluctuation equilibrium-start linear change-accelerated linear change of the following year". The process of biological clogging of emitters was described quantitatively. The effects of the quality of reclaimed water, the types of emitters, the structural parameters of the channel and the frequency of emitters on the biological clogging of emitters were investigated. Based on the characteristics of biological clogging of emitters, the key factors including length of channel, ratio of width to depth and mean shear force near wall are proposed to evaluate the anti-clogging ability of emitters from a brand-new point of view (Ia), Ia). The method of estimating Ia by rated flow rate and channel structure parameters of emitters was established with the aid of dimensional analysis theory, and the accuracy and feasibility of using Ia to quickly evaluate the anti-clogging ability of emitters were verified. The characteristic components of clogging substances in emitters were tested by means of modern environmental microbiology, and the "S-shaped curve" relationship between the characteristic components of clogging substances and the clogging degree of emitters was determined (R20.92, p0.01). The clogging degree of emitters showed a trend of "sensitive-extremely sensitive" with the increase of blocking material composition. The way of the formation and growth of characteristic components of blocking substances on the clogging process of emitters was found out. Considering the effects of nutrient transport and hydraulic shear force distribution, the effects of the types and structural parameters of emitters, different positions of drip irrigation capillary tubes and fertilizer types on the formation and growth of clogging materials were systematically studied. The reasonable control threshold under each influence factor is put forward. Taking the Logistic growth model as the prototype, the key influencing factors such as the structure type of the emitters, the geometric parameters of the runner and the position of the capillary were considered comprehensively. The kinetic model can be used to describe the growth process of the composition of clogged matter (R _ (20.85), p _ (0.01), which is suitable for growth, rapid growth and dynamic stabilization (R _ (20.85), p _ (0.01). The evolution characteristics of microbial communities which play an important role in the blockage of emitters were quantified, the key strains in the process of emitters blocking were determined, the inducing mechanism of biological clogging in emitters was deeply revealed, and a reasonable control strategy for clogging of emitters was put forward.
【學(xué)位授予單位】：中國農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S275.6
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本文編號：2442567