How to Clean

Membrane manufacturers and cleaning-chemical vendors typically have cleaning procedures formulated for their specific product(s). While it is impossible to review all cleaning procedures here, a basic cleaning procedure is presented which can be modified to suit the membrane, the cleaning chemical(s), and the specific contaminant(s) to be removed  

Prepare the cleaning solution. If the solution is in liquid form, it just needs to be pH-adjusted and heated. If the solution is in dry form, it needs to be mixed (using 

RO-permeate or better quality water), pH-adjusted and heated 

Recirculate the solution. The solution should be recirculated at about 35 gpm per pressure vessel. In other words, for an 8-pressure vessel stage with 8-inch diameter membrane modules, the recirculation rate should be 8 times 35 gpm or 280 gpm. Recirculation should be conducted using as little pressure as possible, thereby minimizing the formation of permeate. If permeate is generated, it increases the likelihood of re-deposition of removed species on the membrane.1 If the cleaning solution comes out dark, it should be discarded and a new batch should be prepared. Temperature and pH should be monitored and adjusted during the recirculation as needed. Recirculation should continue for about 45 to 60 minutes. 

High-flow recirculation. The solution should be recirculated at about 40 - 45 gpm per 8-inch pressure vessel 

High-flow recirculation. The solution should be recirculated at about 40-50 gpm per 8-inch pressure vessel for about 45 minutes. Note that higher flow rate recirculation may result in pressure drop issues. The solution should be recirculated at no more than about 50 psig for 8-inch diameter, six-element pressure vessels. 

Flush the membranes. Membranes should be flushed following cleaning using RO-permeate quality or better water. Pretreated feed water should not be used as components may interact with the cleaning solution and precipitation of foulants my occur in the membrane modules. The minimum flush temperature should be 20°C.  

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Womer, T.W., How to Clean Screws Nondestructively, Plast. TechnoL, July, 23 (2009)... 

The sixth item is a series of three HPLC laboratory experiments. The first familiarizes the student with getting a system up and running and calibrating a column with standards. The second experiment shows how to clean a column and pacify a system. The last is a first, quick look at methods development. 

Because different materials get onto and in a frit, different cleaning processes are required to clean a frit. For this reason, storage is an important aspect of frit cleaning. If you know what got on a frit, you know how to clean it. Keeping a frit in a clean, dry, and dust-free area will simplify your cleaning needs. Before a fritted filter is first used, it should be rinsed with hot sulfuric acid and then with distilled water until the filtrate is neutral in pH. This procedure will remove any glass particles and dust that may be on the new frit. 

Another way fluid contamination can occur is during fluid retrofit. If the original fluid is not completely removed from the system, it will contaminate the new fluid causing certain problems. In many cases a fluid can be contaminated by mistake. An operator may unintentionally add a wrong fluid into the tank to top off the original fluid. This can be a serious problem if the two fluids are incompatible. How to clean a system is discussed in the following section. 

Knows how to clean areas that have been contaminated with radioactive materials... 

Highly toxic substances. The cleanup of highly toxic substances should not be attempted alone. Other personnel should be notified of the spill, and the appropriate safety or industrial hygiene office should be contacted to obtain assistance in evaluating the hazards involved. These professionals will know how to clean up the material and may perform the operation. 

Explain how to clean work surfaces in the facility (e.g., what cleaners are used). 

Explain how to clean up broken glass or a contaminated spill. 

Explain how to clean reusable sharps (if appropriate to the facility). 

Most solids don t present high hazards when spilled since they do not disperse easily. If some solid chemical is spilled at your lab bench, a dispensing area, or in a balance room, you should have someone protect the area so that other students are aware of the spill and can avoid any contamination and then notify your instructor about the spill. Your instructor may tell you how to clean up the spill or someone else may take care of it. When cleaning up a solid spill, it is usually best to use a small brush and dustpan to gather most of the solid. This should not be returned to the original bottle, since it is... 

Prepare for spills that you might experience by learning how to clean up a spill, finding the nearest spill kit, and understanding how to use this effectively. 

Prepare for emergencies that might result from handling catalysts—know what to do in case of fires and explosions. Know how to clean up spills of potentially hazardous materials. 

The procedure should prescribe how to clean up the spilled substance and the personal protective equipment (gloves, respirators) that should be worn in such a case. Specific emergency kits are used in hospital pharmacies and wards where antineoplastic medicines are handled and administered. These ready-to-use kits, also called spill boxes, are commercially available A standard content is provided by the ESOP (European Society of Oncology Pharmacy) [85]. 

Each kind of protective eyewear is designed to protect against specific hazards. By completing the hazard assessment of the workplace outlined in the previous section, you will be able to identify the specific workplace hazards that pose a threat to employees eyes and faces. Train employees to use and care for the eye protection provided. Employees must know how to clean their eye protectors. Allow time at the end of their shifts to do the following ... 

TABLE 19-2 How to Clean Tower Trays by Acid Washing... 

How to Clean a Heating System. Cleaning a system (either steel or copper piping) is neither difficult nor expensive. The materials for cleaning are readily available. Trisodium phosphate, sodium carbonate, and sodium hydroxide (lye) are the materials most commonly used for cleaning. They are available at paint and hardware stores. 

Call your teacher rather than trying to clean a spill yourself. Your teacher will tell you whether it is safe for you to clean up the spill if it is not safe, your teacher will know how to clean up the spill. 

Workers need not be trained in work practices that do not pertain to the renovations they will be performing. If the certified renovator will be the one posting warning signs, establishing containment, and cleaning the work area after the renovation, it is not necessary for the certified renovator to provide instruction on these tasks to any workers who will be used elsewhere on the project. Similarly, workers hired to perform only exterior projects need not receive training in how to clean an interior work area after a renovation. 

We know that although there is concern as to how to clean these twisted tube bundles, in some cases, the run length has been so long that even years after installation there still has been no need to clean the bundle. Apparently when it works well, it works very well. 

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