TABLE 2.

Rates of substrate consumption and CH₄ production, cumulative masses of degraded substrate or produced CH₄, and a substrate-CH₄ balance

Test	Zero-order substrate degradation rate (mM day−1)a	Cumulative (total) mass of degraded substrate (mmol)	CH4 production rate (mM day−1)		Cumulative (total) mass of produced CH4 (mmol)	Percentage of the degraded substrate mass that was recovered as CH4 %
			Theoretical	Measureda
PPTac	0.38 ± 0.02	557	0.38	0.048 ± 0.004	158	28
PPTfo	1.86 ± 0.12	268	0.47	0.43 ± 0.043	44	65
PPTH2	0.91 ± 0.02	157	0.23	0.52 ± 0.046	74	188
PPTme	0.11 ± 0.01	58	0.083	0.026 ± 0.0004	26	60
PPTBESb	0.17 ± 0.01	46	0.042	−0.28 ± 0.055	−49

^aValue±standard deviation.

^bZero-order degradation rate and cumulative substrate degraded in PPT_BES refer to H₂ degradation.