Abstract: The basic material properties and potential environmental risks of fecal sludge from urban public toilets were preliminary discussed. Taking five public toilets in Shanghai as the research object, various methods were used to determine the nutrient, pathogenic microorganism, heavy metals, and antibiotic content in its fecal sludge, in order to provide specific data support for the subsequent resource utilization of fecal sludge. The results showed that the fecal sludge was rich in organic matter and nutrients, while could be used as the fertilizer raw material, but the carbon-nitrogen ratio (C/N) was significantly lower than the C/N ratio required (15~25) for general conventional composting treatment processes. All samples contained fecal coliform, fecal enterococci, and salmonella, with fecal coliform levels ranging from 53 700 n/g to 92 100 n/g. The content of heavy metals in fecal sludge was much lower than that in municipal sludge, and the environmental risk indexes of Zn, Cu, Cr, Cd, Pb, and Ni were all below 10. The composite risk index was 19.36, indicating low eco-risk. The ecological risk levels of tetracycline, chlortetracycline and sulfamethoxazole detected in the five groups of fecal sludge were the second risk level, that is, although the ecological risk of antibiotics in fecal sludge for direct agricultural use was low, it could not be ignored. Therefore, urban fecal sludge from septic tank has a high potential for resource utilization, but appropriate treatment technologies need to be selected to cope with the above potential risks.

Key words: fecal sludge, material characteristics, pathogenic bacteria, antibiotics, heavy metals