Potential of acetic acid to restore methane production in anaerobic reactors critically intoxicated by ammonia as evidenced by metabolic and microbial monitoring

Table 2 Process status of the reactors before initiating the process recovery strategy (day 0)

Process stability indicator	LNR	HNR1	HNR2	HNR3
pH	7.11	8.36	8.32	8.30
TAN (g_N L⁻¹)	0.56	17.92	18.20	17.64
FAN (g_N L⁻¹)	0.01	4.07	3.84	3.59
TS (g kg⁻¹)	22.5	27.2	29.90	30.00
TVFA (g kg⁻¹)	0.03	21.99	21.99	23.63
Acetate (g kg⁻¹)	0.02	17.68	17.49	18.91
Propionate (g kg⁻¹)	0.01	3.34	3.46	3.73
Biogas production (L_N L⁻¹ week⁻¹)	6.52	ND	ND	ND

FAN free ammonia nitrogen, HNR1,2,3 free ammonia intoxicated reactors, LNR low nitrogen input reactor used as a reference reactor, L_N normalized litre of gas, ND not detected, TAN total ammonia nitrogen, TS total solids, TVFA total volatile fatty acids.

ISSN: 2731-3654