RO system trouble shooting —– membrane elements fouling and solution

September 5, 2012 Leave a comment

RO system trouble shooting —– membrane elements fouling and solution

Symptoms of trouble:

PP cartridges of security filter seriously blocked after 7 working days by yellow colloidal fouling, and this colloidal substance also follow through the security filter and effect the RO membrane elements, especially the first stage.

Cause: By analyzing the process, we conclude the sulfur bacteria increasing due to the Sodium Bisulfite (SBS) overdosing. At the pretreatment process, the Chloride Dioxide is dosed as bactericide in the depositing reservoir, and before the water go to the RO unit, the Sodium Bisulfite (SBS) is dosed to protect RO membranes. The overdosed SBS reduce not only residual chlorine, but also free oxygen, this will create an anaerobic environment, and the remnant sulfur compounds provide energy source for sulfur bacteria metabolism, which are anaerobic.

Solution:

To cut off the energy source of sulfur bacteria and inhibit its growth. There are two ways to avoid SBS overdoing: to get accurate value of residual chlorine, then recalculate SBS dosing; or to get ORP value of feed water (without any chemical dosing) as reference value, to decide SBS dosing

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RO membranechemical cleaning

August 2, 2012 Leave a comment
Chemical

Foulant

0.1%(w)NaOH

1.0%(w)Na4EDTA

PH12 35oC max

0.1%(w)NaOH

0.025%(w)Na-SDS

PH12 35oC max

0.2%(w)HCl

PH1~2 25oC

1.0%(w)

Na2S2O4

PH5 25oC max

0.5%(w)

H3PO4

PH1~2 25oC

1.0%(w)

NH2SO3H

PH3~24

25oC

2.0%(w)

Citric acid

 

Inorganic Salts

(eg.CaCO3)

Preferred Alternative Alternative Alternative
Sulfate Scales

(CaSO4,BaSO4)

Preferred Alternative
Metal Oxides

(eg. iron)

Preferred Alternative Alternative Alternative
Inorganic Colloids(silt) Preferred
Silica Alternative Preferred
Biofilms Alternative Preferred
Organic 1stcleaning

Alternative

1stcleaning

Preferred

2ndcleaning

Preferred

The Most Competitive Seawater Desalination System

2000, 3000, 5000LPD seawater desalinaiton RO systemThe most competitive desalination system

Competitive price, reliable working performance and long service life.

Treatment capacity: 2ooo to 5ooo liters per day

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Bottled water for emergency

March 28, 2012 Leave a comment

now, people begin to support bottled water again due to the frequent disaster recent years, for example, in Japan, the earth quake tsunami and nuclear leaking  led to water pollution,  it was emergent to provide clean and safe drinking water in short time , the most easy and quick solution was, transport mass bottled water from safe area to  disaster area.  Emergency water treatment device cant work  or play a  major role  due to various factors.

Most Important Comparisons of Drinking Water Specifications

Parameters

WHO

 

Guidelines of  Drinking Water Quality 1999

 

USA

 

USEPA National Primary Drinking Water Regulations

 

EU

 

European Communities Drinking Water Regulations 2000

 

Colour

15 TCU*

15  Colour Units

Acceptable to consumers and no abnormal change

Odour

No guideline

3 Threshold Odor Number

Acceptable to consumers and no abnormal change

Taste

No guideline

Turbidity

5 NTU*

NA

Acceptable to consumers and no abnormal change

Chlorine

No guideline

4 mg/L  as Cl2

Maximum Residual Disinfectant Level

Not mentioned

PH

No guideline

6.5 – 8.5

6.5-9.5

TDS

1000 mg/L*

500 mg/L

Not mentioned

Total Hardness as CaCO3

No guideline

Not mentioned

Not mentioned

Calcium as Ca

No guideline

Not mentioned

Not mentioned

Magnesium as Mg

No guideline

Not mentioned

Not mentioned

Alkalinity

No guideline

Not mentioned

Not mentioned

Chloride

250 mg/L *

250 mg/L

250 mg/L

Fluoride

1.5 mg/L

4.0 mg/L

1 mg/L

Nitrate

50 mg/L

as  NO3

10 as N2 / 44.44  as NO3

50 mg/L

Nitrite

3(P)

1 as N2

0.50 mg/L

Sulphate

250 mg/L*

250 mg/L

250 mg/L

Iron

0.3 mg/L *

0.3 mg/L

0.2 mg/L

Ammonia

1.5mg/L*

Not mentioned

0.3 mg/L

Aluminum

0.2mg/L*

0.05 – 0.2 mg/L

0.2 mg/L

Arsenic

0.01 mg/L (P)

0.01 mg/L

0.05 mg/L

Antimony

0.005 mg/L (P)

0.006 mg/L

0.01 mg/L

Asbestos

No guideline

7 MFL

Not mentioned

Barium

0.7 mg/L

2 mg/L

Not mentioned

Beryllium

No guideline

0.004 mg/L

Not mentioned

Brass

No guideline

Not mentioned

Not mentioned

Boron

0.3 mg/L

Not mentioned

1 mg/L

Bromate

0.025 mg/L (P)

Zero

0.01 mg/L

BOD

No guideline

Not mentioned

Not mentioned

Cadmium

0.003 mg/L

0.005 mg/L

0.005 mg/L

Chromium

0.05 mg/L (P)

0.1 mg/L

0.05 mg/L

Copper

2 mg/L (P)

1.3 mg/L

Zero

Cyanide

0.07 mg/L

0.2 mg/L

0.05 mg/L

Dissolved Oxygen

No guideline

Not mentioned

Not mentioned

Hydrogen  sulphide

No guideline

Not mentioned

Not mentioned

Lead

0.01 mg/L

0.015 mg/L

0.01 mg/L

Manganese

0.5 mg/L (P)

0.05 mg/L

0.05 mg/L

Mercury

0.001 mg/L

0.002 mg/L

0.001 mg/L

Molybdenum

0.07 mg/L

Not mentioned

Not mentioned

Nickel

0.02 mg/L

Not mentioned

Zero

Selenium

0.01 mg/L

0.05 mg/L

0.01 mg/L

Silver

No guideline

0.1 mg/L

Not mentioned

Sodium

200 mg/L

Not mentioned

200 mg/L

Potassium

Not mentioned

Not mentioned

Not mentioned

Thallium

Not mentioned

0.0005 mg/L

Not mentioned

Zinc

3 mg/L

5 mg/L SS

Not mentioned

Anionic detergents

Not mentioned

Not mentioned

Poly nuclear aromatic hydrocarbon

Not mentioned

Zero

0.0001 mg/L

Poly chlorinated bi phenyl

Not mentioned

Not mentioned

Not mentioned

Phenolic compounds

Not mentioned

Zero

Not mentioned

Total Trihalomethanes

Zero

0.1 mg/L

Trihalomethanes

(bromoform)

0.1 mg/L

Not mentioned –

Not mentioned –

Trihalomethanes

(chloroform)

0.2 mg/L

Not mentioned

Not mentioned

Acrylamide

0.0005 mg/L

Zero

0.0001 mg/L

Benzene

0.01 mg/L

Zero

0.001 mg/L

Benzo pyrene

0.0007 mg/L

Zero

0.00001 mg/L

1,2 dichloro ethane

0.03 mg/L

Zero

0.003 mg/L

Epichlorohydrin

0.0004 mg/L (P)

Zero

0.0001 mg/L

Tetra chloro ethane

0.04 mg/L

Zero

0.01 mg/L

Trichloroethane

0.07 mg/L

Zero

0.01 mg/L

Vinyl chloride

0.005mg/L

Zero

0.0005 mg/L

Carbon tetra chloride

0.002 mg/L

Zero

Not mentioned

Dichloroethane

0.05 mg/L

Zero

Not mentioned

Xylene

0.5 mg/L

10

Not mentioned

Toluene

0.7 mg/L

1 mg/L

Not mentioned

Carbofuran

Not mentioned

0.004 mg/L

Not mentioned

Chlordane

Not mentioned –

Zero

Not mentioned

Chlorobenzene

0.3 mg/L

0.1 mg/L

Not mentioned

Ethyl benzene

0.3 mg/L

0.7 mg/L

Not mentioned

Styrene

0.02 mg/L

0.1 mg/L

Not mentioned

Dibromo chloromethane

0.1 mg/L

Not mentioned

Not mentioned

Bromodichloromethane

0.06 mg/L

Not mentioned

Not mentioned

Monochloramine & di & trichloramine chlorine

3

Not mentioned

Not mentioned

Dichloramine & Trichloramine chlorine

5

Not mentioned

Not mentioned

Pesticides

Not mentioned

Not mentioned

mg/L Total Pesticide 0.0005mg/L)

1) Lindane

0.002 mg/L

0.0002 mg/L

Not mentioned

2) Endrin

0.002 mg/L

Not mentioned

3) Diquate

0.02 mg/L

Not mentioned

4) Glyphosphate

0.7 mg/L

Not mentioned

5) Heptachlor

0.00003 mg/L

Zero

Not mentioned

6)Heptachlorepoxide

0.00003 mg/L

Zero

Not mentioned

7) Picloram

0.5 mg/L

Not mentioned

8) Simazine

0.002 mg/L

0.004 mg/L

Not mentioned

9) Toxaphene

Zero mg/L

Not mentioned

10) 2,4,5 TP (Silvex)

0.05 mg/L

Not mentioned

11) Endothall

0.1 mg/L

Not mentioned

12) Alachlor

0.02 mg/L

Zero

Not mentioned

13) Atrazine

0.002 mg/L

0.003 mg/L

Not mentioned

14) DDT

0.002 mg/L

Not mentioned

Not mentioned

15) Aldrine/Dieldrin

Not mentioned

Not mentioned

16) Endosulphan

Not mentioned

Not mentioned

17) Chlorpyriphos

Not mentioned

Not mentioned

18) Malatheon

Not mentioned

Not mentioned

19) 2,4 D

0.03 mg/L

0.07 mg/L

Not mentioned

20) Isoproturon

0.009 mg/L

Not mentioned

Not mentioned

21) Alpha HCH

Not mentioned

22) Beta HCH

Not mentioned

Not mentioned

Not mentioned

23) Delts HCH

Not mentioned

Not mentioned

Not mentioned

24 Monocrotophos

Not mentioned

Not mentioned

Not mentioned

25) Ethion

Not mentioned

Not mentioned

Not mentioned

26) Phorate

Not mentioned

Not mentioned

Not mentioned

27) Butachlor

Not mentioned

Not mentioned

Not mentioned

Radioactive material

Alpha, Beta, Radium 226 Radium 228 & Uranium

0.1 Bq/L  for Alpha and 1 Bq/L for Beta

Zero

Tritium-100 Bq/Lb

Bacteria – Coliforms

Zero

Zero

Zero

Bacteria – E.Coli

Zero

Zero

Zero

Enterococci

No guideline

No guideline

Zero

HPC-colony

Not mentioned

Not mentioned

Zero

Clostridium perfringens (spores)

Not mentioned

Not mentioned

Zero

Virus

No guideline-

Zero

Not mentioned

Protozoa- Cryptosporidium

No guideline

Zero

Not mentioned

Protozoa-Gairdia

No guideline

Zero

Not mentioned

Chlorine disinfection for swimming pool

Chlorine dioxide dosing system for swimming pool water disinfection

 

 

 

 

 

 

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