EM Technology Of Waste Water Treatment

PROBLEM SOLVING:
Source of the anser : https://www.researchgate.net/post/Why_is_water_is_becoming_dark_black_in_an_aeration_tank_in_a_wastewater_treatment_plant

Why is water is becoming dark black in an aeration tank in a wastewater treatment plant?

I've worked on a wastewater treatment plant at a catering service last week. Their wastewater treatment process as follows,

1. Screening

2. Grit chamber

3. Oil trap

4. Areation

5. Settling Tank

6. sand Filter, etc.

They are facing a problem as the wastewater getting black color after aeration and the sludge is not settling in the settling tank thereafter. Also, their is a huge odor occurred in the aeration tank now.

What will be the reason for this and what will be the solution?

ANSWER:

It means you have incresed the organic load to your aeration tank as a result there is a shortage of oxygen in the aeration tant .This can be checked by measuring DO in the aeration tank & should be  about  1.5 to 2 mg/l.

A) Please check for malfunctioning of Aeration system fouled membranes etc

B) You can improve the situation by cutting down load to the aeration tank  by reducing the flow or the inlet BOD concntration or by adding more air to th aeration tank.

C) Ensure that you are not dumping some chemical like food preservative,detergent, oil or off spec product in the waste water system  as this can increase the ETP load.

It  will take about 4 to 8 hours to restore,  if you balnce the BOD load and the oxygen supply ( 1.5 Kg O2/Kg BOD loading) subject to you have not spolied the biomass otherwise it may take 2 to 3 days to bring the normalcy.

If you need  more correct solution you  may have to share design  and operation details

Note : The black colour is due to shortage of oxygen ( less oxygen/more organic load) and will vanish once you restore the balance.Normally the healthy biomass should  be brownish  in colour  and smell like moist soil.