Technical assistance: How is the concentrated water resulting from the reuse of treated wastewater generally handled? !
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This post was last edited by cdpulin on 2011-11-28 at 13:42. Our company is planning to install a system for reusing treated water. I’m wondering how concentrated wastewater is typically handled; if it is sent back to the wastewater treatment plant, will this have any impact on the treatment process over time?
What substances are contained in the concentrated solution, and what are their concentrations?
Reply to 1# lei1840: It cannot be reused, as doing so will lead to an increase in salt content over time, which is detrimental to biochemical processes.
Concentrated water cannot be returned directly to the system; a separate concentrated water reuse system is required, with a recovery rate of around 75%. If zero discharge is desired for the remaining concentrated water, evaporation crystallization must be used, or it can be used for direct combustion in coal furnaces
It can be seen that you plan to use the dual-membrane process for reuse. At present, apart from the high operating costs associated with this process, another issue is that of concentrated brine – RO not only concentrates salts but also COD. If environmental regulations where you are don’t impose any requirements regarding salt content, then I think the issue you need to worry about is the COD level of the concentrated water – you can’t just add fresh water to it before discharging it! I think I’d better consider other technologies besides the membrane method! I know a technique that can solve the problem you’re worried about!
By the way, it’s definitely not possible to go back to the frontend; it won’t take long before problems arise in the biochemical processes. No one designs reclaimed water reuse in this way.
Concentrated wastewater with high salt content and high COD can still be treated, though the investment required is high. As for the remaining concentrated wastewater, it depends on how you decide to handle it
It is sent back to the wastewater treatment system for further processing.
This post is quite good; with so many projects related to reclaimed water reuse, the RO concentrate is surely something that deserves everyone’s attention.
The opinions from the fourth and fifth floors are quite reasonable; if the concentrated water has no value for recycling and there are no environmental discharge standards requiring anything else, then it can just be discharged
In some cases, the concentrated water is sent to the wastewater treatment plants in industrial parks, where it is treated centrally, usually by evaporation! Because such water has high salt content and high COD!