New efficient meta-fermentation process for lactic acid production from municipal solid waste

Table 4 Summary of operating parameters and average results of lactic acid production during OFMSW fermentation trials at pilot scale

Nr. of Feeding strategy	Duration (d)	Operational conditions			Results 1500-L digester (digestate)									Yield (gLA/g TS feeding)
Nr. of Feeding strategy	Duration (d)	OLR (kg_VS/ m³d)	OLR (gO₂/L·d)a	HRT (d)	pH (-)	TS (%)	COD (gO₂/L)	Lactic acid (g/100 g)	Lactic acid (g/gTS)	Lactic acid (gCOD/kg)	Lactic acid (g_COD/L)b	% D-Lactic	% L-Lactic	Yield (gLA/g TS feeding)
1	14	11.7	17.5	6	4.10 ± 0.57	5.25 ± 1.77	45.35 ± 8.91	2.00 ± 1.28	0.36 ± 0.12	21.39 ± 13.80	22.24	56.20 ± 4.38	43.80 ± 4.38	0.25
2	12	12.2	18.3	4	4.20 ± 0.14	5.70 ± 0.71	51.13 ± 5.83	2.70 ± 0.00	0.48 ± 0.06	28.69 ± 0.00	29.84	56.60 ± 4.38	43.40 ± 4.38	0.44
3	14	34.3	51.5	2	4.35 ± 0.07	7.30 ± 2.26	45.76 ± 2.95	3.45 ± 0.21	0.50 ± 0.18	37.01 ± 1.69	38.49	52.75 ± 0.92	47.25 ± 0.92	0.38
4	14	25.8	38.7	2^c	5.00 ± 0.14	7.30 ± 0.28	52.73 ± 1.80	3.65 ± 0.92	0.50 ± 0.15	39.20 ± 9.58	40.77	49.20	50.80	0.54
5	7	26.2	39.4	2^d	6.35 ± 1.77	6.00 ± 0.14	54.23 ± 8.31	2.15 ± 1.48	0.36 ± 0.26	22.83 ± 16.44	23.74	47.80 ± 3.25	52.20 ± 3.25	0.30
6	7	32.5	48.7	2^e	5.13 ± 0.06	6.99 ± 0.45	57.55 ± 0.92	3.75 ± 0.02	0.54 ± 0.04	39.95 ± 0.23	41.54	50.35 ± 0.49	49.65 ± 0.49	0.41

HRT hydraulic retention time, OLR organic loading rate, TS total solids, COD chemical oxygen demand
^aFactor of 1,5gCOD per 1 gVS
^bAverage value transformed considering the digestate density (1.04)
^cpH-Adjustment at 7 once a day
^dpH-Adjustment at 7 continuously
^epH-Adjustment at 7 once a day and addition of 10L of BAL-inoculum

ISSN: 1475-2859