Table 1.

Characteristics of sludge samples collected from different processes of wastewater treatment plant

Sample name	Sample collection location	Sample description	Tep	Salt	DO	Post-QC reads number	Reads utilization (%)	ORFs number	CAG-ORFs percentage (%)
Stanley_AS	Stanley WWTP	Suspended proportion of AS-treating fresh wastewater	A	F	Aer	164,298,394	56.4	1,217,440	3.03
Stanley_BF	Stanley WWTP	Attached to the carrier proportion of AS-treating fresh wastewater	A	F	Aer	175,985,866	52.1	1,348,161	1.46
ST_AS_winter	Shatin WWTP	Activated stage treating saline wastewater collected at winter	A	S	Aer	49,496,374	40.6	306,862	1.70
ST_AS_summer	Shatin WWTP	Activated stage treating saline wastewater collected at summer	A	S	Aer	50,164,884	37.4	300,883	1.88
ST_ADS	Shatin WWTP	Full-scale anaerobic digester treating saline wastewater	M	S	An	31,818,174	47.4	158,417	1.86
SWH_ADS	Shek Wu Hui WWTP	Full-scale anaerobic digester treating fresh wastewater	M	F	An	36,670,382	51.5	67,636	6.70
MAD	Lab-scale Anaerobic digester	Lab-scale anaerobic digester at mesophilic condition	M	S	An	25,253,200	42.5	128,509	2.02
TAD	Lab-scale Anaerobic digester	Lab-scale anaerobic digester at thermophilic condition	T	S	An	22,464,032	42.7	116,511	2.25
TCF	Lab-scale Anaerobic digester	Lab-scale thermophilic anaerobic digester enriched with cellulosic substrate	T	F	An	50,255,458	89.8	91,808	4.83

Tep category of temperature, A ambient temperature, M mesophilic, T thermophilic, Salt category of salinity, F fresh, S saline, DO category of dissolved oxygen, Aer aerobic, An anaerobic, Reads utilization percentage of reads included in the de novo assembly, AS activated sludge, WWTP wastewater treatment plant, BF biofilm, ADS anaerobic digestion sludge