Development of Pillared Clays for Wet Hydrogen Peroxide Oxidation of Phenol and Its Application in the Posttreatment of Coffee Wastewater

Table 4

Physicochemical parameters of coffee wet processing wastewater before and after biological treatment in SMTA.

Parameters	Water characteristics
	Before^a	After^b
pH	4.2	6.5
BOD5 (mg O2/L)	2,990	284
COD (mg O2/L)	6,580	551
COD/BOD	2.2	1.9
Total suspended solids (mg/L)	435	904
Acidity (mg/L)	413	72
Total phenols (mg/L)	ND	165

^aAnalysis conducted at Cenicafé.
^bAnalysis after biological treatment in hydrolytic acidogenic and methanogenic reactors (SMTA).
ND: Not determined because the sample contained a large amount of reducing sugars that generated interference and overestimated the total phenols content.