（1）預(yù)處理
反滲透系統(tǒng)的效率和壽命與原水的預(yù)處理效果密切相關(guān)。通過(guò)預(yù)處理可以有效地減少進(jìn)水對(duì)膜的污染、結(jié)垢、損傷風(fēng)險(xiǎn)，使膜的使用壽命延長(zhǎng)，降低運(yùn)行費(fèi)用。
（2）進(jìn)水的pH值
pH值的高低對(duì)膜系統(tǒng)的性能也有很大的影響，垃圾滲濾液在進(jìn)入DTRO之前需將pH值調(diào)為酸性，一方面可以防止難溶無(wú)機(jī)鹽結(jié)垢，另一方面可以使?jié)B濾液中游離氨與加入的酸形成二價(jià)氨鹽，而DTRO對(duì)類似多價(jià)離子的截留率很高，這就能提高最難去除的氨氮的去除率。
改變進(jìn)水pH值會(huì)對(duì)反滲透膜的透過(guò)性產(chǎn)生影響，隨著pH值的逐漸升高，透過(guò)液的流量與pH值成反比，pH值越高，透過(guò)液流量越小，但在pH值大于7后出現(xiàn)了拐點(diǎn)，之后pH值繼續(xù)升高，透過(guò)液流量反而增大。因此，進(jìn)水pH值偏酸性或偏堿性均有利于提高產(chǎn)水通量。
垃圾滲濾液水質(zhì)本身極為復(fù)雜性且含鹽量高，隨著系統(tǒng)的運(yùn)行，難溶鹽易在系統(tǒng)末端積聚最終使膜片結(jié)垢影響透水量。所以，反滲透處理進(jìn)水的pH值需控制為酸性，同時(shí)考慮后續(xù)減少加堿量，可將進(jìn)水pH值范圍控制在6左右。
（3）系統(tǒng)的運(yùn)行壓力
反滲透系統(tǒng)的運(yùn)行壓力是影響反滲透技術(shù)運(yùn)行成本的最重要因素，對(duì)反滲透膜的正常使用也有極其重要的影響。由于滲濾液水質(zhì)的特點(diǎn)，較高的壓力有利于對(duì)污染物的截留。但是較高的壓力也更容易造成膜組件的堵塞和污染。 膜系統(tǒng)的產(chǎn)水通量與運(yùn)行壓力近似呈現(xiàn)出線性關(guān)系。同時(shí)，膜系統(tǒng)的脫鹽率也隨進(jìn)水壓力的增大而升高。
（4）系統(tǒng)的回收率
回收率是反滲透的重要指標(biāo)， 定義為透過(guò)液的體積除以原液體積。將電導(dǎo)率20000μs/cm 的滲濾液作為研究對(duì)象，控制進(jìn)水壓力在4.0MPa左右。調(diào)節(jié)回流泵同時(shí)調(diào)節(jié)控制閥，使進(jìn)水流量與透過(guò)液產(chǎn)水量同步提升，從而改變膜組件的回收率，系統(tǒng)回收率與透過(guò)液通量成反比。這是因?yàn)榉礉B透過(guò)程是一個(gè)在進(jìn)水端施加壓力逆轉(zhuǎn)稀溶液向濃溶液自然滲透的過(guò)程。
膜組件的脫鹽率與透過(guò)液通量成正比， 這是因?yàn)榈屯高^(guò)液通量時(shí)，進(jìn)水側(cè)的鹽濃度相對(duì)較高，較大的鹽通量和較低的透過(guò)液通量自然會(huì)出現(xiàn)脫鹽率較低的結(jié)果。
（5）進(jìn)水溫度的影響
溫度對(duì)膜片本身性能的影響十分嚴(yán)重， 隨著溫度的升高，水粘度逐漸下降，產(chǎn)水通量會(huì)逐漸升高。在對(duì)膜系統(tǒng)設(shè)計(jì)時(shí)應(yīng)充分考慮溫度對(duì)膜截留率的影響因素， 通過(guò)膜片廠商提供的修正系統(tǒng)以及其他方式， 將運(yùn)行參數(shù)標(biāo)準(zhǔn)化有利于準(zhǔn)確掌握系統(tǒng)的運(yùn)行狀況。
隨著溫度的升高，膜片的脫鹽率逐漸降低，透過(guò)液的色度升高且水質(zhì)變差。這是因?yàn)殡S著溫度的升高，鹽分透過(guò)膜片的擴(kuò)散速率將逐漸加快，最終大于水透過(guò)膜片的速率，表現(xiàn)為膜片脫鹽效率的降低。
(1) preprocessing
The efficiency and life of reverse osmosis system are closely related to the pretreatment effect of raw water. Pretreatment can effectively reduce the fouling, scaling and damage risk of the influent, prolong the service life of the membrane and reduce the operation cost.
(2) the pH value of the influent
The pH value also has a great influence on the performance of the membrane system. The landfill leachate needs to turn the pH value into acidity before entering the DTRO. On the one hand, it can prevent the insoluble inorganic salts from scaling. On the other hand, the free ammonia in the leachate and the added acid can form the two valence ammonia salt, and the retention of the DTRO like polyvalent ions is very high. It can improve the removal rate of ammonia nitrogen which is the most difficult to remove.
The change of the pH value of the influent will affect the permeability of the reverse osmosis membrane. With the increasing of the pH value, the flow flow is inversely proportional to the pH value. The higher the pH value, the smaller the flow flow, but the inflection point after the pH value is greater than 7, and then the pH value continues to rise and the flow flow increases. Therefore, the pH value of the influent is acidic or alkaline, which is conducive to increasing the water production flux.
The water quality of landfill leachate itself is very complex and has high salt content. With the operation of the system, the insoluble salts are easily accumulated at the end of the system and eventually make the scale of the diaphragm affect the permeability. Therefore, the pH value of the reverse osmosis water treatment should be controlled to be acidic. At the same time, the pH value range of the influent can be controlled to about 6 when considering the reduction of alkali addition.
(3) the operating pressure of the system
Reverse osmosis system operation pressure is the most important factor affecting the operation cost of reverse osmosis technology, and has a very important impact on the normal use of reverse osmosis membrane. Because of the characteristics of leachate, higher pressure is favorable for the interception of pollutants. But higher pressure is also more likely to cause blockage and pollution of membrane modules. There is a linear relationship between the flux and the operating pressure of the membrane system. At the same time, the desalination rate of membrane system increases with the increase of influent pressure.
(4) the recovery rate of the system
The recovery rate is an important index of reverse osmosis, which is defined as the volume of liquid through the volume divided by the volume of the original solution. The leachate with conductivity of 20000 s/cm was used as the research object to control the influent pressure of 4.0MPa. The reflux pump regulates the control valve at the same time, so as to synchronize the flow of water with the water output of the liquid, so that the recovery rate of the membrane module is changed, and the recovery rate of the system is inversely proportional to the flux through the liquid. This is because the reverse osmosis process is a process of applying pressure at the inlet end to reverse the natural infiltration of dilute solution into concentrated solution.
The desalination rate of the membrane component is proportional to the permeation flux, which is due to the relatively high salt concentration in the inlet side, and the relatively low desalination rate of the larger flux and the lower permeation flux.
(5) influence of water inlet temperature
The effect of temperature on the performance of the membrane is very serious. With the increase of temperature, the viscosity of water gradually decreases and the water production flux gradually increases. In the design of the membrane system, the influence factors of the temperature on the film interception should be fully considered. Through the correction system provided by the diaphragm manufacturers and other ways, the standardization of the operating parameters is beneficial to the accurate control of the operating condition of the system.
With the increase of temperature, the desalination rate of membrane decreases, the color of permeation liquid increases and the water quality becomes worse. This is because with the increase of temperature, the diffusion rate of the salt through the diaphragm will increase gradually, which is greater than the rate of water passing through the diaphragm, which shows the decrease of the desalination efficiency of the diaphragm.
