Methane potentials of wastewater generated from hydrothermal liquefaction of rice straw: focusing on the wastewater characteristics and microbial community compositions

Table 1 pH, COD, TOC, and UV₂₄₅ values of HTLWW samples under different HTL conditions

Parameters	170 °C–0.5 h	200 °C–0.5 h	230 °C–0.5 h	260 °C–0.5 h	290 °C–0.5 h	320 °C–0.5 h	200 °C–1 h	200 °C–2 h	200 °C–4 h
pH	5.56 ± 0.01	4.09 ± 0.02	3.81 ± 0.21	3.72 ± 0.07	3.69 ± 0.12	3.68 ± 0.07	3.86 ± 0.10	3.80 ± 0.02	3.81 ± 0.09
COD g/L	11.35 ± 1.19	27.58 ± 1.82	22.25 ± 2.05	24.33 ± 1.98	29.02 ± 1.09	24.33 ± 1.19	23.2 ± 1.04	14.28 ± 2.88	19.00 ± 3.29
TOC g/L	3.92 ± 0.03	9.99 ± 1.12	8.55 ± 0.12	8.88 ± 0.50	10.27 ± 1.04	9.23 ± 0.87	9.03 ± 0.32	5.18 ± 0.93	7.29 ± 0.02
Organic in HTLWW %^a	12.11 ± 1.27	29.42 ± 3.08	23.74 ± 3.25	25.96 ± 2.11	30.96 ± 4.16	25.96 ± 1.26	24.75 ± 1.10	15.23 ± 3.07	20.27 ± 3.51
UV₂₅₄/COD^b	2.46 ± 1.19	2.57 ± 2.89	3.91 ± 3.05	2.48 ± 1.98	2.24 ± 3.90	1.99 ± 1.19	4.39 ± 1.04	4.63 ± 2.99	3.95 ± 3.29

^aThe percentage organics (in COD values) in HTLWW, COD of rice straw input in HTL process was calculated according to C, H, O, and N elemental compositions
^bUV₂₅₄ unit was 1/m

ISSN: 2731-3654