Raw sludge

In plants with primary and secondary digester, raw sludge is pumped to the primary digester displacing partially digested sludge. 

For therapeutic drugs, the highest concentrations in the raw sludge corresponded to the analgesics diclofenac (209 ng g ) and ibuprofen (135 ng g-1), and the sulfonamide antibiotic sulfathiazole (143.0 ng g-1). Next in abundance were the diuretic compounds furosemide (79.9 ng g-1) and hydrochlorothiazide (41.3 ng g-1), and the analgesic ketoprofen (42.4 ng g-1). The remaining PhC were found at concentrations below 40 ng g The list of the 24 detected... 

OC (7.71 pg g-1), EHMC (1.03 pg g 1) and 4-MBC (0.520 pg g 1) were the most abundant UV-F detected in the raw sludge. The remaining sunscreens were found at concentrations below 0.1 pg g 1. Removal values were higher than 58% for most of the compounds (Table 2), including the complete elimination of BP1. Only BP3 was poorly removed (22%), while 4DHB showed complete recalcitrance and could not be transformed in the process. Higher removals were expected for the least... 

The results about the removal of UV Filters were contrary to the expected. Higher removals were expected in slurry system for the least hydrophobic UV Filters and lower in solid-phase. 4DHB and BP3, least hydrophobic than OC and EHMC, were completely removed in solid phase and only BP3 was poorly removed in slurry treatment while 4DHB showed recalcitrance. In general, for all UV Filters detected in raw sludge, better removal values in solid phase treatment were obtained. 

Therefore, bacteria take up phosphate from solution and store it in the form of polyphosphate. Phosphate is removed as the excess organisms are separated from the system. These organisms, with the phosphate they contain, are added to and treated with the raw sludge, ultimately producing a treated sludge product richer in nutrients. 

Raw sludge is filter-pressed and the resulting cake is mixed with slaked lime (i.e., calcium oxide). The reaction of lime with moisture increases temperature and pH sufficiently so as to kill pathogens. The entire... 

Table II. Reduction of Substrates in Raw Sludge During Digestion...

Lipid Extration Procedures. Lipid was extracted from raw sludge with chloroform and methanol according to the method of Bligh and Dyer (22). Prior to use as a substrate, the lipid extract was dispersed in 2% Tween 80 by sonicating for 30 minutes at 60 °C. 

After the addition of the normal raw sludge substrate (Figure 1), the acetate concentration doubled immediately at zero time because of the presence of acetate in the substrate thereafter, acetate continued to... 

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