Metals present in municipal wastewater may still be present in treated sewage sludge; __________.
cause damage to the municipal works
interfere with coagulation and flocculation
kill bacteria used in wastewater treatment
a and c but not b
all of the above
Historically, the use of chlorine bleach has made the pulp and paper industry an important source of __________ contamination.
polychlorinated biphenyls (PCBs)
Chlorination of drinking water is highly effective at killing __________.