. 2019 Dec 31;17(1):283. doi: 10.3390/ijerph17010283

Table 3.

Summary of the average steady-state performance comparative study of the conventional (R1) and modified (R2) UASB reactors effluent and biogas production.

Fixed Parameter
HRT 24 h
Run	Duration (Days)	Influent COD (g L⁻¹)	OLR (g L⁻¹ d⁻¹)	Biogas Production (L/d)		Methane Content (%)		SMP (LCH₄/gCOD _added)		pH		Alkalinity (mg/L) R1		Alkalinity (mg/L) R2		Alkalinity Ratio (IA/PA)		NH₃-N (mg/L) Effluent
		R1,R2	R1,R2	R1	R2	R1	R2	R1	R2	R1	R2	IA	PA	IA	PA	R1	R2	R1	R2
I.	15	3.5	1.75	6.2	6.8	71	88	0.210	0.28	6.6	6.8	42	302	32	322	0.14	0.09	141	156
II.	16	6.0	3	7.9	8.6	67	83	0.150	0.19	6.7	6.8	43	306	42	219	0.14	0.19	185	204
III.	17	10.0	5	10.2	12.2	72	83	0.120	0.18	6.7	7.3	45	248	41	235	0.18	0.17	428	550
IV.	16	20.0	10	8.0	27.0	44	89	0.020	0.21	4.2	7.3	51	58	35	175	0.88	0.20	163	651
V.	16	28.0	14	5.8	22	33	64	0.010	0.08	4.4	6.8	68	61	32	185	1.11	0.17	104	712
VI.	15	32.0	16	3.6	14	26	55	0.004	0.04	43	6.7	72	51	37	154	1.42	0.24	1590	753

COD: chemical oxygen demand; HRT: hydraulic retention time; SMP: specific methane production; NH₃-N: ammonia nitrogen; IA: intermediate alkalinity; PA: partial alkalinity.