(k) During biological N removal, what happens in the anoxic zone? i) NOx generation ii) High in NOx iii) Converting NOx to N2 iv) No additional organic addition (1) Which EPA requirement should be fulfilled to apply biosolids to land without further pathogen regulation? i) Class A requirement ii) Class B requirement iii) 1" biosolids requirement iv) Class 1 requirement (m) Which is more acutely toxic? i) LD50 = 5 mg/kg BW ii) LD50 = 1000 mg/kg BW (n) Under what circumstances can a registered engineer sign and seal plans or documents he/she did not prepare? i) Registered engineers can coordinate ii) Under no circumstances. projects that include segments that they are not competent in if a qualified registered engineer signs and scals plans or documents for those segments of the project iii) If the plans or documents were prepared iv) When practicing in a state different than by someone under the registered engineer's the one in which the engineer is registered. direct supervision and the registered engineer is an expert in the subject matter.