Lesson 5 - Effluent Treatment SAQ
This lesson allows you to test yourself on the material covered in the Effluent Treatment lesson and determine the level to which you have met the learning outcomes.
Suggested Response - Q4
** In order to reuse water from effluent, what equipment would you consider? From a discharge perspective, what could present a problem with water reuse?
Response:
In order to reuse water from effluent, we use the reverse osmosis (RO) process. This is because it delivers water free from biological organisms and removes all compounds which can contribute to taints and off-flavours and all other ions which can potentially react in the process. However, this is the final step and we first need to reduce the effluent load effectively by employing anaerobic and/or aerobic treatment.
To prepare the water for RO, the effluent should be free of larger particles and bacteria which can foul the system. This can be done with ultrafiltration after anaerobic treatment. It can also be done by incorporating a membrane filter as part of the aerobic treatment by using a membrane bioreactor.
As water is reused in the process, the total volume of effluent is reduced. Thus, compounds that are rejected by the RO filter as concentrate will be present in higher concentrations than would be the case if water was not reused. This can lead to issues with disposal.