Dear Ayushi,

Your effluent should be treated first by secondary treatment process then pass through tertiary treatment process composing of membrane filters, active carbon and reverse osmosis. By doing these step you will reach the ZLD.

For further information on these processes you can download related papers from my Research gate profile (RAFIK KARAMAN).

Good Luck

Considering high content of chloride, Sulfide, Ammonical Nitrogen, and Heavy Metals, Please go for Physico-chemical Treatment (Advanced Oxidation Process), Aeration, and then go for Multiple Effect Evaporation.

Technically, RO is not ZLD, as it generates high concentrate brine.

Dear Ayushi,,

Best described by Mr Sameer & Mr. Rafik and addition to Heavy metal treatment 

The heavy metals present in the neutralized waste water from plant can be removed by Chemical precipitation with Sodium Sulphide.

The Chromate treatment and heavy metal precipitation plant consist essentially of chemical treatment for the removal of the following pollutant (however the Chromate treatment has been stopped due to cooling water treatment dosing changed):

1. Removal of hexavalent chromium after its reduction to the trivalent state with sodium metabisulphite at a PH range of 2.0 to 3.0 followed by chemical precipitation as chromium hydroxide Cr(OH)3 with lime at an optimum PH

2. Removal of Silica from the Cooling Tower blow down by activated magnesia

3. Chemical precipitation of heavy metals like Arsenic, Copper, Chromium, Nickel, Zinc &

Vanadium by Sodium sulphide under alkaline condition

1.      Vanadium: as Vanadium sulphide

V2+ + Na2S = VS + 2 Na+

2.      Arsenic: as Arsenic Sulphide

2 As3+ + 3 Na2S = As2S3 + 6 Na+

3.      Nickel: as Nickel Sulphide

Ni2+ + Na2S = NiS + 2 Na+

Chromium Removal

Chemical Reaction

The chemical reaction for reduction of hexavalent chromium to trivalent state with sodium Meta bisulphite at a PH range of 2.0 to 3.0 takes place stoichiometric ally and is an instantaneous reaction according to the following equations.

 4 H2CrO4 + 3 Ca(OH)2 + 3 H2SO4 = 2 Cr2(SO4)3 + 3 Na2SO4 + 7 H2O

 The Trivalent Chromium is removed as chromium hydroxide by precipitation it with lime at PH 8.5 to 9.0 as follows.

 Cr2 (SO4)3 + 3 Ca(OH)2 = 2 Cr(OH)3 +3 CaSO4

 The solubility of chromium hydroxide is negligible and is of the order of 8.4X10-4 mg/lit at PH 9.0

For more detail please see following link

https://www.researchgate.net/publication/283619633_Effluent_Treatment_and_Biohydrolyser_for_Ammonia_and_Urea_Plant_waste_streams

regards,

prem baboo

Article Effluent Treatment and Biohydrolyser for Ammonia and Urea Pl...

I think there is only one way to achieve ZLD by solidifying the final liquid discharge qty., how you have research on this , however I can give a hint there are certain polymers available in the market which can absorb water quickly and remain in solid form another one is stabilize with fresh soil allow it for natural dry evaporation, test it for leachate followed by dumping in land fill Hazardous or Inert.