Table 1 Comparison of VFAs yield from WAS fermentation by co-digesting carbon-rich substrates

Adjusting pH (8)-treated WAS

Thermal-treated rice (TTR)

(Solid)

50:50% (VSS_WAS:VSS_TTR)

520 mg COD/g VSS

[16]

WAS

Perennial ryegrass (Solid)

20:1 (C/N)

369 mg COD/g TS

[15]

Mixed sludge (MS)

Lime-treated bagasse (LTB) (Solid)

30:70%, 40:60% and 60:40% (g_MS:g_LTB)

360 mg carboxylic acid/g VS

[31]

Alkaline- thermal treated WAS

Agaricus bisporus substrates (ABS) (Solid)

45:55% (VSS_WAS:VSS_ABS)

514 mg COD/g VSS_WAS+ABS

[36]

WAS

Sugar beet pulp lixiviation (SBPL) (Solid)

75:25% (v_SS:v_SBPL)

350 mg COD/g VSS

[32]

Dewatered WAS

Food waste (FW) (Solid)

12:88% (VSS_WAS:VSS_FW)

393 mg/g VSS

[50]

Ultrasonic treated WAS

Alkaline treated CS hydrolysate

65:35% (VSS_WAS:VSS_CS)

583 mg COD/g VSS

This study