Hi from your data, I feel it is a moderately clean effluent. It is really depended on where the effluent goes further. Is it for drinking water or discharge back to natural circle? And also which country are you in? Every country has a standard on the effluent of water plant, you must meet the numbers(i.e.TDS) embeded in that regulation. 

On the other hand, RO consumes a lot of energy. You need to perform a cost-benifit analysis to see whether this option worth it.

NeWater plants in Singapore are world-leading and they publish a lot of information and standards in the website of National Environment Agency. Their technology is mainly developed by Nanyang Technological University, so this is another source for you to check.

Hi Akash, one technology are evaporators. The link below explains how they work. 

http://www.evaporator.com/reverse-osmosis-reject

Donaji, As of now I am giving Multiple Effect Evaporator treatment for RO Reject of same quality mentioned in my question. But it found to be costly treatment method.

Yilei Liao, We are using all the treated water in different cooling towers, Domestic purpose and in Gardening purpose.

Actually I am looking for some sustainable treatment method which will not only reduce my operation cost but also it should not create any reject or effluent after treatment as RO does.    

Hello Akash,  a possible low cost solution  is the construction of Artificial Wetlands planted with local salt tolerant vegetation ( for example, mangroves) . If  the effluent doesnt acheve the quality standards of your country, you could add , after the wetland treatment, an evaporation pond . A pilot-scale experiment would be suitable .

sorry Donaji but I don't have much space, but yes its a good idea to have some salt tolerant flora species as we already have quite large garden area.