A2. Hi
The various methods of disposal of 7000 ppm TDS RO reject is as follows.
1. watering plants.
2. send to sewage disposal.
3. can reuse by passing through softener bed.
4. you can also evaporate , condensate can be reused, but costly, will lead to scaling/fouling.
5. you can also use this High TDS water for toilet flushing.
Hope this may help you.
bye,