Nitrate consumption by the oxidation of sulfides during an enhanced natural attenuation project at a contaminated site in Berlin, Germany

Environmental Sciences Europe

Table 6 Mass balance of nitrate, sulfate, and sulfide for the main experimental phase (mg)

	Biologically active column	Abiotic column
Sulfate formation
SO₄²⁻ inflow	249.9	226.0
SO₄²⁻ outflow	666.6	251.6
SO₄²⁻ formation	416.6	25.6
Sulfide oxidation
Total amount of oxidized iron disulfide	260.5	16.1
Total mass of oxidized iron disulfide in the soil	87.4 (mg kg⁻¹)	5.4 (mg kg⁻¹)
Total amount of oxidized sulfide	139.1	8.6
Total mass of oxidized sulfide in the soil	46.6 (mg kg⁻¹)	2.9 (mg kg⁻¹)
Nitrate consumption
Incomplete chemolithotrophic denitrification (Eq. 1)	941.8	58.1
Complete chemolithotrophic denitrification (Eq. 2)	376.7	23.2
Oxidation of bivalent iron formed (Eq. 3)	26.9	1.7
Chemoorganotrophic denitrification (Eq. 4)	404.8	3.8
NO₃⁻ consumption calculated according to Eqs. 1, 3, 4	1373.5	63.6
NO₃⁻ consumption calculated according to Eqs. 2, 3, 4	808.4	28.7
NO₃⁻ inflow	7262.6	7630.8
NO₃⁻ outflow	5797.2	7506.2
NO₃⁻ consumption measured	1465.4	124.2