Lesson 4 - Effluent Treatment
In this lesson we take a closer look at effluent from a utilities perspective. We will consider different forms of effluent treatment.
Combined Anaerobic and Aerobic Treatment
For many breweries, combining both anaerobic and aerobic treatment provides the best of both worlds.
So, what would a typical installation look like?
We use anaerobic treatment to reduce the overall loading whilst producing biogas. It also substantially reduces sludge removal volumes. Aerobic treatment can then be used to remove further COD. Given that the bulk of the work has been done already, the aerobic plant can then be much smaller than otherwise.
How does this stack up in terms of energy, sludge production, and space requirements? The table below shows three different combinations.
Table: Comparison of options
|
|
Aerobic Only |
Combination 1 |
Combination 2 |
|
Anaerobic |
------ |
IC |
IC |
|
Aerobic |
Activated sludge |
Activated sludge |
Airlift |
|
Net energy |
-5 MJ/hL |
+12 MJ/hL |
+12 MJ/hL |
|
Biomass (sludge to be removed) |
0.25 kg TS/hL |
0.05 kg TS/hL |
0.05 kg TS/hL |
|
Space |
1000 m2/hL |
800 m2/hL |
150 m2/hL |