Developing horizontal subsurface flow constructed wetland using pumice and Chrysopogon zizanioides for tannery wastewater treatment

Environmental Systems Research

Table 4 TWW Treatment Efficiency of HSSFCW with Gravel and Pumice Substrate and Planted with CZ at Different HRT

Parameters	Influent conc.(mg/l)	3 days HRT		5 days HRT		7 days HRT		9 days HRT
Parameters	Influent conc.(mg/l)	Pumice (%)	Gravel (%)	Pumice (%)	Gravel (%)	Pumice (%)	Gravel (%)	Pumice (%)	Gravel (%)
BOD₅	1641 ± 373.55	83.36	89.05	95.49	89.58	96.42	90.96	96.30	91.85
COD	6953.33 ± 339.41	92.34	93.82	96.76	95.81	96.91	95.94	96.62	96.33
NH₄-N	253.33 ± 11.6	89.41	19.08	98.03	34.47	98.16	52.63	97.30	61.97
NO₃-N	116.66 ± 26.63	90.72	66.29	100	77.15	99.68	80.86	99.51	86.00
TN	650.33 ± 93.62	93.54	68.27	98.67	86.11	99.00	90.42	98.56	88.67
PO₄-P	88.06 ± 40.77	92.81	90.92	96.55	95.20	96.97	95.68	100	96.33
TP	144.53 ± 20.75	86.39	88.47	94.79	88.93	96.17	91.47	41.97	92.16
TSS	1868 ± 863.1	94.66	95.41	95.77	95.93	95.72	96.09	96.04	96.25
TDS	5877.3 ± 2294.77	74.39	79.96	78.24	79.95	86.92	81.96	86.42	81.23
TCr	18.33 ± 6.66	95.20	96.40	98.36	97.27	98.91	97.44	98.09	97.27