What's in Your Sludge? Hunting for Baby Granules in Full-Scale Activated Sludge Treatment Plants

摘要

Mixed liquor from continuous flow activated sludge (CFAS) facilities with enhanced biological phosphorus removal (EBPR) contained 0.5 to 80.2 percent granules based on 212-um sieve size. The so-called baby granules were relatively small (mostly less than 400 — 600 μm in diameter), displayed smooth morphology and dense core, resulted in lower SVI_30, and had higher abundance of PAO and GAO than the floe. Higher % granules were related to anaerobic staging and more available biodegradable sCOD. This work is the first to show that granules are indeed commonly present in CFAS facilities and to observe types of systems and factors that encourage granular growth. Methods to assess granular presence in CFAS facilities have been shown.