6 replies to this topic

[Molefe]

Greetings everyone,

 

I would like to ask for some guidelines/useful information:

 

I am a graduate trainee in a chemical distribution company, apart from making sodium hypochlorite (NaClO) we do a lot of mixing and blending of acids,bases. The plant is divided into 2 sections i.e. The Acid-Alkali and Solvents section. The liquid waste is generated from these 2 sections. The municipality requirements require that the following water quality parameters be not violated with the liquid discharge from the plant:

 

1. PH range: 5.5-12.0

2. Conductivity should not exceed 500mS/m

3. Both Chlorides and Sulphates should not exceed 1500mg/L

4. COD : 5000mg/L 

 

The only treatment currently is PH correction with Acid or base (Caustic Soda). Sometimes the operator combines the waste (organic) from solvents section in attempt to neutralize the PH before using Acid/Base. The only thing measured in the lab is the PH and conductivity, the rest they get fined for it whenever it exceeds the limits. What would be the effective way to deal with concentration of sulphates,chlorides and possibly keep the COD within the limits as well. 

 

Please may you give me any information/thoughts and advices that will be useful to me

 

Molefe.

[breizh]

http://www.gewater.c...dbook/index.jsp

 

Hi Molefe,

 

Consider this resource to support your work.

Good Luck

 

Breizh

[P.K.Rao]

1. Reverse Osmosis is one way to remove chlorides and sulfates. The waste from RO is small and you can dispose it by land fill within your plant. Outlet of RO will contain low chlorides and sulfates. Percolation through soil  is permitted by most municipalities and Government Bodies if it does not enter underground water through ducts and does not contain heavy metals like chromium, barium etc and radio active metals.

2. Chlorination or Hydrogen peroxide treatment will reduce COD.

[Molefe]

Thank you very much Breizh I have followed the link and will use the resource intensively. 

 

Thank you very P.K.Rao for useful information I will consider it.

[Molefe]

I have read about the Reverse Osmosis and other available technologies that can be used to reduce the concentration of sulphates and chlorides below the set maximum. However these technologies cannot be applied immediately (economic reasons) considering the amount of liquid waste Effluent we are generating.(Last year) alone we discharged  5 168 070 Liters to the municipal sewer and we were charged a lot of money for exceeding the concentration of these anions (SO4^2- and Cl ^-). In general we discharge a minimum of 200 000 Liters of liquid waste every month. Our PH and Conductivity is seemingly manageable because we use caustic and acids for PH regulation and we use water for keeping conductivity within the limits and it's generally not a problem.

 

​Most of the waste is generated from, washing tanks, flobins, blowpack, loading and offloading zone, from after doing some mixing and blends. We are a chemicals distribution company, the only thing we make is Sodium Hypochlorite. Most of the problematic waste is our aqueous waste (Usually Acidic/Basic)

 

 

What would be an alternative way you would suggest for reducing my sulphates and chloride Concentration?

Edited by Molefe, 28 January 2015 - 02:40 AM.

[breizh]

Molefe,

 

Can you concentrate (evaporation)   your solution to reduce the volume and recover the water ? You may be able to landfill the concentrate solution .

 

 

Hope this helps

 

Breizh

[Molefe]

Technically I can. But considering the amount (200 000 Liters) of liquid waste I process per month, it may not be immediately implemented.