Novel Electrochemical Treatment of Spent Caustic from the Hydrocarbon Industry Using Ti/BDD

Table 2

Analysis of PTEs in spent caustics mixture.

		MLA (mg L^−1) in rivers
PTE (mg L^−1)		Agricultural irrigation (A)		Public-urban (B)		Protection of aquatic life (C)
		p.d	p.m	p.d	p.m	p.d	p.m
Al	15.46	—	—	—	—	—	—
As	<0.098	0.2	0.4	0.1	0.2	0.1	0.2
Cd	<0.114	0.2	0.4	0.1	0.2	0.1	0.2
Co	2.42	—	—	—	—	—	—
Cu^*	6.89	4.0	6.0	4.0	6.0	4.0	6.0
Cr^*	1.95	1.0	1.5	0.5	1.0	0.5	1.0
Fe	1,323	—	—	—	—	—	—
Mn	7.23	—	—	—	—	—	—
Ca	148.87	—	—	—	—	—	—
Mg	34	—	—	—	—	—	—
Na	19,148	—	—	—	—	—	—
Hg^*	0.07	0.01	0.02	0.005	0.01	0.005	0.01
Ni^*	6.75	2	4	2	4	2	4
Pb^*	1.23	0.5	1	0.2	0.4	0.2	0.4
Zn	4.68	10	20	10	10	20	10
V	0.24	—	—	—	—	—	—

MLA = maximum limits allowed; p.d = per day; p.m = per month.
^*Values that exceed the established MLA under Mexican Regulation.