微灌系统堵塞的原因与防治措施探讨

微灌系统堵塞是微灌系统运行中常常出现的现象,也是影响微灌技术推广应用的主要障碍。对微灌系统堵塞的主要原因和防治措施进行了阐述和分析,指出水质因素是造成微灌系统堵塞的直接原因,根据水质等因素合理设计和配置过滤设备以及在运行中进行正确的管理和维护是防治微灌系统堵塞的关键措施,而对灌水器经济技术性能的改进则是从微灌技术本身出发寻求解决堵塞的另一有效方法。     

硬水灌溉陶瓷灌水器堵塞特性研究

受水资源短缺的限制,我国仍有较多地区采用硬水进行灌溉。硬水易引发灌水器堵塞,为探明硬水灌溉下水的硬度对陶瓷灌水器堵塞的规律及堵塞机理,选取砂基陶瓷灌水器,使用杨凌自来水和配制的3种不同总硬度的硬水进行灌溉实验,观察其在55 d内流量变化过程,观察灌水器内堵塞物质形态,并借助X射线衍射仪检测堵塞物成分、含量。结果表明:硬水会造成灌水器堵塞,且水质越硬,堵塞越严重;硬水灌溉条件下,陶瓷灌水器流量随时间的变化过程分为"波动阶段"和"下降阶段",且水质越硬,流量下降越明显;堵塞物质分析表明CaCO_3沉淀是灌水器堵塞的主要原因。堵塞物影像表明,运行时间越长,水质越硬,堵塞物沉积越严重。研究结果为陶瓷灌水器在水质较硬地区的推广提供了参考。     

微灌系统过滤器的应用与管理

0前言微灌是按作物需求,通过管道系统与安装在末级管道上的灌水器,将水和作物生长所需的养分以较小的流量,均匀、准确地直接输送到作物根部附近土壤的一种灌水方法。它提高水资源的利用率,改良作物的品质,促进农业生产的自动化控制;但微灌系统由于其灌水器的流道细小,极易被杂质堵塞,所以对水质的要求较其他的灌溉方式高得多。     

微灌用网过滤器与砂过滤器综述

微灌的特点是使用过水流道窄细或出水口很小的灌水器,极易被水中的各种污物堵塞。从而使微灌工程失效。因此,微灌要求灌溉水中不含能造成微灌堵塞的杂质。而实际上任何水源,如湖泊、塘库、河流和沟溪等水源,都不同程度的含有各种污物,即使是水质     

雨水集蓄工程中的一种高效灌溉方式——微灌

雨水集蓄工程是指对降雨进行收集、汇流、储存和进行节水灌溉的一套系统。节水灌溉系统是实现雨水高效利用的最终措施，而微灌是其中最常见的一种灌溉方式，其主要特点是以低压小流量出流将灌溉水供应到作物根区土壤，可以实现局部灌溉。微灌通常分为微喷和滴灌。微灌的主要优点是省水、省工、节能，灌水均匀度高，增产优质，对土壤和地形的适应性强，可充分利用小水源。其主要缺点是灌水器过水断面小，容易引起堵塞，因此对水质要求严格。一、雨水集蓄灌溉工程的特点1、水量较少，只能采取局部灌溉方式。2、一般一口集雨池作为一个灌水系统…     

自吸式全自动网式过滤器运行中存在问题及解决措施

过滤器是微灌工程处理水源的重要设备,自吸式全自动网式过滤器能有效清除灌溉水中的颗粒杂质,提高灌溉水水质,节省劳动力,提高灌水的机械化程度,但其在实际运用中还存在滤网变形、积垢和被有机质堵塞等问题,会对灌水系统的正常运行造成不利影响。对应用在大田灌溉系统的自吸式全自动网式过滤器在生产运行中存在的滤网变形、积垢和被有机质堵塞等问题进行初步分析,通过合理地选择滤网目数、缩短自清洗的周期、加强水质监测处理以及化学方法,有效的保障过滤器的正常运行。     

不同灌溉模式下微孔混凝土灌水器流量变化规律研究

以尿素、磷酸二氢铵、硫酸钾3种化肥为例,详细研究了微孔混凝土灌水器在不同灌溉模式下的流量变化规律。结果表明:单纯灌水时,灌水器流量会小幅下降,灌水器内少量沙粒被水剥离堵塞微孔是导致其流量下降的主要原因,灌水器的孔径较大,自来水中的离子在其微孔中沉积对其流量影响很小。水肥灌溉时,加入不同的化肥对灌水器的流量影响很大;尿素中不含难溶物质,加入水中不影响灌水器的流量变化规律;磷酸二氢铵和硫酸钾中含较多难溶物质,加入水中会堵塞灌水器的微孔,导致灌水器流量快速下降;将磷酸二氢铵和硫酸钾配成溶液进行过滤后再加入水中,可避免灌水器堵塞,保证灌水器流量稳定。该研究为微孔混凝土灌水器的科学使用奠定了基础。     

泥沙粒径对大流道迷宫灌水器堵塞影响研究

为探明大流道迷宫灌水器发生物理堵塞的成因及堵塞过程,采用连续加沙灌溉和间歇灌溉相结合方法,研究了粒径小于0.15mm的8种泥沙颗粒对灌水器堵塞和灌水系统均匀性的影响。结果表明,浑水含沙量在低于2g/L范围内变动对灌水器堵塞没有明显影响;当含沙量为2.0g/L时,泥沙粒径是造成大流道迷宫灌水器堵塞的主要原因,引发堵塞敏感粒径范围为0.10~0.15mm,且堵塞形式主要表现为突然完全堵塞,粒径为0.058~0.075mm的泥沙颗粒最不易引发堵塞;极易堵粒径相互组合会加剧灌水器的堵塞,易堵粒径组混合在一起有减轻堵塞效果的作用。相较于常规滴灌灌水器的易堵粒径,0.1mm以上粒径的泥沙颗粒更易滤除,在浑水灌溉时可优先选用大流道灌水器。     

微灌系统中过滤装置的应用

通常微灌系统是由水泵（自来水管道）、压力表、阀门、过滤器、连接件组成的首部枢纽和担负着输配水任务的各主管、支管、毛管组成的管网系统以及直接向作物根部供水的各种形式的灌水器组成。其中灌水器是完成灌水任务的末端关键设备,为了使灌水器能正常工作,过滤器的选择和工作性能就显得至关重要。如果过滤器的选择不当,就会导致灌水器堵塞,会引起给水不均和系统性能下降,甚至造成整个微灌系统瘫痪,这样就会因修复或重建系统造成大量的人力、财力的浪费。     

微灌系统堵塞机理分析与微灌过滤器研究进展

以杂质颗粒堵塞微灌系统的时空变化过程,研究了微灌灌水器堵塞的机理与形成过程,详细阐述了灌水器堵塞的类型及其关系和堵塞规律。针对不同类型的过滤器过滤机理进行了分析,最后提出了微灌过滤技术发展及过滤设备存在的问题和建议。     

Surface topographic characteristics of suspended particulates in reclaimed wastewater and effects on clogging in labyrinth drip irrigation emitters

Drip irrigation is the most effective and reliable method for reclaimed wastewater irrigation. Emitter clogging is the major problem for extending the drip irrigation technology. The existence of suspended particulates in irrigation water is the main reason for the emitter clogging. However, the reclaimed wastewater quality is extremely complex, and there is a series of physical, chemical, and biological reactions between suspended particulates and other materials contained such as microorganisms, which make the characteristics of suspended particulates in reclaimed wastewater complicated. In this paper, two types of widely used wastewaters treated with fluidized-bed reactor (FBR) and biological aerated filter (BAF) processes respectively were selected. The scanning electron microscope (SEM) technology and fractal theory were used to quantitatively describe the characteristics of the surface topography of suspended particulates. The results showed that the suspended particulates in two reclaimed wastewater were flocculent and porous. The pore system mainly consisted of solid suspended particulates, and most areas between the particulates were filled with microbes and extracellular polymers (EPS). The complex structure of biofilms was formed. That the biofilms grew and detached in irrigation system and deposited continuously at the inlet and outlet of labyrinth path was the major reason for the emitter clogging. The surface topography of suspended particulates in both reclaimed wastewaters showed fractal and multifractal characteristics, and the fractal dimension could not characterize the local and microsingularity of particulates but multifractal dimension could. The uniformity of the distribution of sediment pores increased with the size. Comparatively, the uniformity of suspended particulates in reclaimed wastewater treated by FBR was lower. With operation of reclaimed wastewater irrigation system, the average discharge of emitters decreased continuously with obvious fluctuations. The clogging degree of emitters was low during the first 256 h, and the clogging degree of the two types of reclaimed water was similar. But then, the degree of clogging increased greatly, and the FBR treatment on the emitters discharge were more obvious than BAF. It was closely related to the growth, detachments and sediment of biofilms in the irrigation system. Hence, using the reclaimed wastewater treated by BAF for drip irrigation is more suitable.     

化学离子对再生水滴灌灌水器堵塞的影响

为探究不同化学离子(Fe2+、Ca2+)对滴灌灌水器堵塞发生过程的影响及堵塞机制,以二级处理再生水和地下水为水源,选取标称流量为1.1~1.8L/h的4种灌水器进行灌水器堵塞试验。试验中每天灌水12h,定期测定灌水器流量,试验结束后测定灌水器生物膜干重及胞外多聚物EPS重量。结果表明:化学离子改变生物膜的形成过程和结构稳定性,增加了堵塞物质的形成和生长速度;向地下水加入Fe2+增大灌水器发生生物化学堵塞的风险,地下水同时加入Fe2+、Ca2+,灌水器以化学堵塞为主;再生水加入Ca2+提高了灌水器化学堵塞风险,加入Fe2+或同时加入Fe2+、Ca2+增加了发生生物化学堵塞的风险。     

Water quality in drip/trickle irrigation: A review

Summary The intensive treatment of irrigation water required for the proper operation of drip irrigation systems is presently an accepted practice. To control emitter clogging, we need to know the basic causes of clogging. The major clogging factors have been identified and control measures developed to prevent emitter malfunction. All emitter clogging problems, however, have not been solved primarily because of cost. The main approach to control clogging is proper water treatment. The type of treatment is based on the quality of the irrigation water, which can be classified in terms of its physical, chemical and biological composition. The causes of emitter clogging and possible water treatment and preventive measures to maintain reliable operation are reviewed.     

微灌水质分析与指标判定

水质分析对于微灌系统的设计和运行管理至关重要．但目前国外的微灌水质标准不尽统一。我国还没有较为完善的微灌水质标准．导致在实际工程中微灌水质分析没有得到足够的重视。从微灌水质不满足要求容易引发的堵塞、土壤碱化、土壤渗透性降低、作物敏感性、离子毒性等问题入手．详细分析了各种问题对应的水质分析参数．并结合国内外相关经验,提出了微灌水质分析指标体系。     

再生水应用于城市绿地的微灌技术

基于目前城市绿地采用饮用水地面喷灌技术,造成绿地喷灌用水量不均匀且极大地浪费饮用水资源等问题,探讨了应用于城市绿地微灌的再生水处理工艺、处理后再生利用的水质标准及其微灌系统设计技术。通过对再生水绿地微灌系统的设计参数、首部枢纽、管网布置、灌水器的喷洒方式及控制系统等的设计介绍,归纳了城市绿地再生水微灌系统的一般规划设计方法,并对再生水微灌技术应用于城市绿地的经济与社会效益进行了初步分析。经探讨分析认为,再生水微灌技术在城市污水再生利用、降低水环境负荷和推广先进的绿地灌溉节水技术等方面找到了新的结合点,并且对污(废)水再生利用、保护水环境、节约水资源、城市生态景观绿化等技术结合方面的研究与应用起到了较大的推动作用。     

Effects of average velocity on the growth and surface topography of biofilms attached to the reclaimed wastewater drip irrigation system laterals

Emitter clogging, a phenomenon commonly seen in reclaimed wastewater drip irrigation systems, is a severe obstacle to the wide applications and popularization of the irrigation technology. Some experiments showed that the emitter clogging was tightly related to biofilms formation attached to the irrigation system. In this paper, two types of wastewaters reclaimed respectively by fluidized-bed reactor (FBR) process and biological aerated filter (BAF) process were chosen as the experiment objects and then the effects of the average velocity on the growth and topography of biofilms attached to the irrigation laterals were studied. The parameters of biofilms reached their maximal values at a critical velocity of 0.45 m/s. The formation of biofilms was primarily controlled by the transport of the nutrients and suspended particles within the laterals when the average velocity is below the critical velocity, whereas it was primarily controlled by the hydraulic shear force when above the critical velocity. The main mechanism for emitter clogging was that the biofilms detached from laterals accumulated and grew at the inlets and outlets of emitters. A similar variation pattern was observed for both reclaimed wastewaters. However, the growth of biofilms for BAF process was more affected by the shear force than that for FBR process, since the nutrients and suspended particles for BAF were larger than those for FBR.     

Preliminary surface topographical characteristics of biofilms attached on drip irrigation emitters using reclaimed water

Drip irrigation is the most effective and reliable method for reclaimed water irrigation. Emitter clogging is the bottleneck to restrain the application and popularization of reclaimed water drip irrigation technology, and some researchers have reported that this was tightly related to the formation of biofilms in the irrigation system. We selected reclaimed water treated with cyclic activated sludge system (CASS) and four kinds of labyrinth emitters in cusp-shaped saw-tooth, rectangular straight-tooth, arc-shaped saw-tooth and arc-angular straight-tooth and studied the surface topographical characteristics of biofilms in different positions of reclaimed water drip irrigation emitters with the 3D white-light scanning interferometer (WLSI). The results showed that biofilms in different positions of units were different with each emitter while showing the largest thickness in water-side tooth-tip zone (>20 μm); the biofilm thickness in the same monitoring sites inside one unit segment gradually decreased along the flow direction, while the flow at the inlets was much larger than that at the outlets; comparing the head, middle and tail parts, the biofilm thickness at the inlet and outlet showed the largest in the tail part, followed by the middle and the head parts. This can be explained by the equilibrium relation between hydrodynamic behavior and the transportation of nutrient and particles inside the emitters. The water-side tooth-tip zone of the first unit in the last emitter was selected to monitor surface topographical characteristics of biofilms, and its biofilm thickness also could be used as the indicator for evaluating the characteristics of surface topography. These results were aimed to provide references to explain the emitter clogging mechanism of reclaimed water drip irrigation as well as its technological application and popularization.     

Eight emitters clogging characteristics and its suitability under on-site reclaimed water drip irrigation

Drip irrigation is the most effective and reliable method for reclaimed water irrigation. The water usually contains a lot of suspended particles, metal salt ions, organisms and microbial communities, which will enhance the possibility of emitter clogging or more complex clogging mechanism. Emitter clogging has become one of  the key problems to the application and popularization of the drip irrigation technology. In this paper, we selected four kinds of pressure-compensating emitters and four kinds of non-pressure-compensating emitters, and executed the experiment of drip irrigation with on-site reclaimed water treated with cyclic activated sludge system (CASS). The emitter discharge ratio variation (Dra), coefficient of uniformity (CU) and clogging rate distribution were analyzed to evaluate the emitter clogging characteristics after eliminating the effect of temperature and pressure on the emitter outflow by data correction. The results showed that Dra and CU varied in three periods as system operation. The beginning of experiment was the fluctuated balance period, Dra and CU recurrent fluctuated in 5 %, and the emitters clogged at some spots after the system run 36–48 h. Then the two parameters varied linearly in 60–108 h, tuning into the initiate linear period, as the non-pressure-compensating emitters got an obvious linear change than the pressure-compensating ones with the gradient changed from ?0.094 to 0.042 and ?0.073 to 0.047, respectively. Some of the emitters have a significant difference on these two parameters at this stage. After the restarting in the second year, Dra and CU decreased sharply. The maximum decrement was, respectively, 9.6 and 10.7 %. Then they varied in line with a greater slope degree as all emitters reached the significant level, the gradient ranges were ?0.176 to 0.115 and ?0.216 to 0.117, respectively. This stage was called the accelerated linear period. Seriously clogged and completely clogged emitters appeared, and both Dra and CU dropped down to 38.7 and 41.5 %. Various degrees of clogged emitters often emerged in the end part of lateral at first then propelled to the head gradually, the completely clogged emitters in the end accounted for more than 73.0 % when the system run 540 h. Comprehensively considered, the pressure-compensating emitters and cusp-shaped saw-tooth non-pressure-compensating emitters with short flow path are recommended in reclaimed water drip irrigation. These researches are aimed to provide references explaining the emitter clogging mechanism of reclaimed water drip irrigation as well as its technological application and popularization.     

温度对施肥滴灌系统滴头堵塞的影响

为探究不同灌水温度下水肥一体化滴灌滴头堵塞成因与过程,采用固定周期间歇滴灌的多因素完全随机试验设计方法,分别在冬、夏两个季节研究了3种不同泥沙级配浑水与3个不同施肥质量浓度组合对滴头堵塞的影响和堵塞变化过程。结果表明,灌水温度是影响滴头堵塞的重要因素,与水质交互耦合效应显著,夏季施肥和未施肥2种情况下灌溉滴头的抗堵塞性能均高于冬季,夏季有效灌水次数是冬季的1.26~1.43倍;施肥加速滴头堵塞的作用受泥沙级配和灌水温度的影响,冬季灌溉水中0.034~0.1 mm粒径粗颗粒含量越多,施肥质量浓度对堵塞的影响越敏感,夏季灌溉水中0~0.034 mm细颗粒越多,施肥质量浓度对堵塞的影响越敏感。建议灌水温度较低时,水肥一体化滴灌应控制在较低的施肥质量浓度下灌溉,适当增大次灌水时间,减少灌溉次数。