UF membrane design guidelines

(一)ordinary cleaning method

 

1.ordinary cleaning  method

 

after using UF membrane,due to the separation of substances and other impurities on the membrane surface will accumulate gradually, to the membrane pollution and the congestion, the effective cleaning of membrane is an important means of extending the service life of the membrane. Commonly used cleaning method has two major categories of chemical cleaning and physical cleaning.

 

2.Same pressure cleaning method

 

Ultrafiltration water valve is closed, open the concentrate water outlet valve, wash the membrane surface by increasing flow velocity, the method to remove the film on the surface of the loose impurity effectively

 

3.High-water cleaning method

 

Increased purity of the water, dissolving capacity strengthening. Cleaning can be the first to make use of ultrafiltration membrane surface water will loose dirt, then use pure water cleaning cycle.

 

4.Reverse cleaning method

 

Ie wash water from the mouth into the ultrafiltration membrane and through the membrane and into the mouth while concentrating, using reverse flushing method can effectively remove coverage but backwash should pay special attention to prevent overpressure, to avoid breaking or damaging the membrane sealing adhesive surface.

 

（二）Chemical cleaning method: Using chemical impurities with the membrane surface to achieve the purpos

 

1.Acid cleaning

 

Commonly used solution with hydrochloric acid, citric acid, oxalic acid, etc., mixing solution of PH = 2 ~ 3, the use of circulating wash or soak circulation cleaning, after 0.5 h ~ 1 h on inorganic impurities removal effect is good.

 

2.Alkali cleaning

 

Commonly used alkali mainly include NaOH, mixing solution of the PH = 10 ~ 12 or so, the use of water circulation cleaning operation or soaking 0.5 h ~ 1 h after cleaning, can effectively remove impurities and grease

 

3.Oxidant cleaner

 

Using 1% ~ 3% H2O2, 500 ~ 1000 mg/L NaClO solution ultrafiltration membrane cleaning, can remove dirt, kill bacteria. H2O2 and NaClO is a common fungicides

 

4.Enzymatic detergent

 

Such as 0.5% ~ 1.5% pepsin, trypsin, etc., to remove protein, polysaccharide, fat class pollutants effectively.

 

The principle of choosing chemicals:

1) can't with membrane and components of other materials in any chemical reaction.

2) selection of drugs to avoid secondary pollution.