Services

Membrane cleaners

Cleaning method for RO Membrane

Cleaner	0.1% (W) NaOH	0.1% (W) NaOH	0.2% (W)	1.0% (W)	0.5% (W)	1.0% (W)
	and pH 12, 35℃	and pH 12	HCI, 25℃ and	Na2S2O4, 25℃	H3PO4 , 25℃	NH2SO3H, 25℃
	max. or 1.0%	35℃ max. or	pH 1 - 2	and pH 5	and	and pH 3 - 4
	(W) Na4EDTA	0.025% (W)			pH 1 - 2
	and pH 12	Na-DSS and pH
	35℃ max.	12, 35℃ max.

Foulant

Inorganic Salts (for example, CaCO3)		Preferred	Alternative	Alternative
Sulfate Scales (CaSO4, BaSO4)	OK
Metal Oxides (for example, iron)			Preferred	Alternative	Alternative
Inorganic Colloids (silt)		Preferred
Silica	Alternative	Preferred
Biofilms	Alternative	Preferred
Organic	Alternative	Preferred

The temperatures and pH listed in table 3 are applicable for BW30, BW30LE, LE, XLE, TW30, TW30HP, SW30HR, SW30HR LE , SW30XLE, SW30 and NF90 membrane elements. For more information regarding the allowed temperatures and pH for cleaning, please refer to table 1.

Notes:
1. (W) denotes weight percent of active ingredient.

2. Foulant chemical symbols in order used: CaCO3 is calcium carbonate; CaSO4 is calcium sulfate; BaSO4 is barium sulfate.

3. Cleaning chemical symbols in order used: NaOH is sodium hydroxide; Na4EDTA is the tetra-sodium salt of ethylene diamine tetraacetic acid and is available from the Dow Chemical Company under the trademark VERSENE* 100 and VERSENE 220 crystals; Na-DSS is sodium salt of dodecylsulfate; Sodium Laurel Sulfate;

HCI is hydrochloric acid (Muratic Acid); H3PO4 is phosphoric acid; NH2SO3H is sulfamic acid; Na2S2O4 is sodium hydrosulfite.

4. For effective sulfate scale cleaning, the condition must be caught and treated early. Adding NaCl to the cleaning solution of NaOH and Na4EDTA may help as sulfate solubility increases with increasing salinity. Successful cleaning of sulfate scales older than 1 week is doubtful.

5. Citric Acid is another cleaning alternative for metal oxides and calcium carbonate scale. It is less effective (see also figure 1 of this document). It may contribute to biofouling especially when it is not properly rinsed out.

Cleaning method for Sanitary UF&MF Membrane

Cathonic Pains

PURPOSE		CIRC.TIME	FORMULATION
CC-1	Normal paint fouling	1-2 hours 120。F MAX.	◎ 91.9% D.I.Water
			◎ 3.0% Butyl Cellosolve
			◎ 5.0% Acetic Acid
			◎ 0.1% Citric Sol'n***
CC-2	Cleaning to recover from secere paint fouling	2-4 hours 120。F MAX. Last 30 min only	◎ 93.4% D.I.Water
			◎ 3.0% Butyl Cellosolve
			◎ 3.0% Formic Acid
			◎ 0.1% Citric Sol'n***
			◎ 0.5% Triton X-100

Anionic Paints

PURPOSE		CIRC.TIME	FORMULATION
AC-1	Mild fouling or preventive maintenance	30 minutes	◎ 99.8% Permeate
			◎0.2% Solubilizing Amine **

AC-2	Severe paint fouling	1 hour	◎89.7% Permeate
			◎10.0% Butyl Cellosolve
			◎0.3% Solubilizing Amine **

* To be preceded by chemical cleaning
* * Amine to be specified by paint supplier
*** Citric Acid Solution-50% by weight powered Citrc Acid in D.I Water Triton-X-100:Contact Union Carbide
Note: Acids for cathodic cleaning may be substituted-3% Formic,or 3% Lactic,or 5% Acetic, with approval from paint supplier and AMT.