TABLE 1.

Sludges tested and their phosphorus and quinone contents

Sludge sample	Source	Type of process	Wastewater type	Phosphorus content (μmol/mg of MLSS)a	Quinone content (nmol/mg of MLSS)			MK/Q ratio
					Q	RQ	MK
P-AO1	Shinjiko plant (July 1992)	AO	Raw sewage	1.94	0.396	0.017	0.388	0.981
P-AO2	Shinjiko plant (August 1992)	AO	Raw sewage	1.58	0.442	0.027	0.399	0.903
P-AO3	Shinjiko plant (October 1992)	AO	Raw sewage	1.43	0.470	0.016	0.433	0.922
P-AO4	Shinjiko plant (December 1992)	AO	Raw sewage	0.91	0.501	0.002	0.417	0.833
P-St	Chiba plant	Standard	Raw sewage	0.67	0.474	0.005	0.454	0.958
L-AO/RS	Laboratory	AO	Raw sewage	1.67	0.486	NDb	0.464	0.954
L-St/RS	Laboratory	Standard	Raw sewage	0.62	0.597	ND	0.497	0.833
L-AO/SS	Laboratory	AO	Synthetic sewage	1.94	0.734	ND	0.379	0.517
L-ST-SS	Laboratory	Standard	Synthetic sewage	0.58	0.887	ND	0.404	0.455

^aSum of the phosphorus contents of the acid-soluble, lipid, alkali-soluble, hot-acid-soluble, and residual fractions. 

^bND, not detected.