Physico-chemical characteristics and biodegradability of primary effluent and particulate matter removed by microscreens.

In this study, the physical, chemical and biological characteristics of raw wastewater were compared with the liquid and solid streams generated by a primary clarifier (PC), a rotating belt filter (RBF, 350 μm) and a drum filter (DF, 60 μm) and series (SER) combination of an RBF with a PC or a DF using pilot-scale primary treatment units. The RBF removed about 36% of the influent total suspended solids (TSS inf ). The DF and PC yielded a TSS inf removal of 47% to 55% in both individual (parallel; PAR) and SER configurations. The size fractionation and chemical characterizations of the liquid fractions indicated a significant change in the wastewater composition in both filter configurations with no variation in the biodegradability of liquid fractions. The solids recovered by RBF (RBF-S) had a higher total solids (TS) concentration and a higher volatile solids (VS) content (0.92 g VS/g TS) than that of DF and PC treatments (0.58 to 0.84 g VS/g TS). DF and PC sludge demonstrated a higher biodegradability rate (k 1 ; 0.11 d -1 < k 1 < 0.20 d -1 ) than RBF-S (0.09 d -1 ). The retained solids in the SER configuration demonstrated a significantly lower theoretical biochemical methane potential than the PAR configuration, likely due to the presence of smaller particles with a significantly higher ratio of particulate COD over volatile suspended solids (1.86 to 2.40 g COD/g VSS). These results indicated that the physical, chemical and biological characteristics of liquid and solids from different filter configurations are required to determine design criteria to upgrade or retrofit water resource recovery facilities using an RBF or a DF.