An SBR requires closer attention & monitoring than an Aerated lagoon. Both technologies are reliable, though SBR is more sensitive. I suppose your municipality is looking to “upgrade” to a SBR because of the high organic load due to the effluent from the dairy industry.
The technology in usually used when organic loads are high.
Small footprint (1,000 m3/d = 2,000 m2)
Contains many mechanical components: pumps, blowers, valves, etc.
Daily sludge extraction, storage, and emptying the sludges every +/- 60 days
Sensitive to excessive flow and load variations
Pre-treatment and equalization basin/tank required
May require additional UV disinfection
Are widespread and widely known.
Large footprint (1,000 m3/d = 10,000 m2)
Significant reduction of sludge / Sludge management every 8 to 12 year
Does not generate odors when the amount of oxygen in the water is sufficient
Does not require pre-treatment
Usually does not require additional UV disinfection