Table 2.

Compositions of feed liquors supplied to bioreactors I and II.

	Bioreactor I feed liquor	Bioreactor II feed liquora,b	Synthetic Mynydd Parys mine waterb (bioreactor I)
pH	2.5→2.1	2.5	2.1
Fe2+c	1.0	3.0	5.0→10
SO42−	3.9→6.4	12.1→56.4	11.7
Cl‐	0.27	Trace	2.1
H2PO4‐	0.15	Trace	0.02
Cu2+	1.0	Trace	0.71
Zn2+	1.0	3.0	1.07
Al3+	Trace	0.5→30	3.33
Mn2+	Trace	0	0.22
Na+	0.38	0.5	2.12
NH4+	2.72	Trace	0.02
K+	0.42	Trace	0.04
Mg2+	0.81	2.0	0.66
Ca2+	0.05	0.5	1.05
Glycerol	5.0→0.7	4.0	3.0→0.7
Yeast extract	0.01	0.01	0.01→0.005

^a.Based on AMD draining the abandoned Cwm Rheidol zinc mine, mid‐Wales.

^b.Data kindly supplied by Dr Hugh Potter, Environment Agency, UK.

^c.At point of discharge.

All concentrations shown are mM, except yeast extract (w/v), and arrows indicate changes in concentrations during the course of the experiment.