Can sludge be treated through anaerobic fermentation again?

What the original poster means is: should the sludge from the aerobic tank go into the UASB, or should the sludge from the UASB be processed anaerobically? If it is sludge from an aerobic tank, it can first be concentrated by gravity before being sent to an anaerobic digester for stabilization; as for anaerobic sludge, it seems to be quite valuable. UASB generally produces little sludge, right?

The order is wrong; it doesn’t seem to be designed this way!

Sludge composting is an option; if you think it’s a shame, then what can be done with sludge through anaerobic fermentation?

It should be fine to use it as a supplement for bacteria; the acclimatization period requires at least a month. However, if the bacteria in the system grow well, its practical value is limited, as sludge mainly consists of waste substances, though it can still be utilized. It depends on what you want to use it for.

It is certainly feasible to subject sludge to anaerobic treatment, and the treatment results are also good. The organic content in sludge is much higher than that in wastewater; therefore, anaerobic treatment of sludge can, first, reduce the organic content in it, second, decrease its volume. Moreover, sludge contains many harmful microorganisms or bacteria, and anaerobic fermentation can help **reduce these harmful substances. Sludge used as fertilizer generally needs to go through an anaerobic maturation stage, with the aim of reducing harmful substances in it. After anaerobic fermentation of sludge, it can be used as a compound fertilizer by adding trace elements; it is widely applied in farming, horticulture, and other fields. Moreover, it helps improve soil structure and prevent soil compaction, advantages that pure chemical fertilizers cannot match.