Does NaOH supplement control sulphate production in aerated mine lake sediment?

摘要

Our study was carried out to evaluate the effects of NaOH supplements on sulphate production in aerated mine lake sediment. Twelve levels of NaOH were added to the sediment to control sulphate biochemical production (SO4_(TOTAL)). It was found that up to 0.29+0.01 mol/kg of SO4_(TOTAL) was produced in all treatments till the end of the experiment (375 hours), regardless of the level of NaOH addition. The NaOH supplement controlled SO4_(TOTAL) production only in the early phases of the aeration (till 200 hours). However, SO4_(TOTAL) production in most NaOH treatments was higher than in untreated control in these early phases. The decrease of SO4_(TOTAL) was observed only in treatments with NaOH additions of 0.4-0.75 mol/kg in the period between 60-150 hours of the aeration. After 200 hours, all variants produced the same amounts of SO4_(TOTAL) as untreated control. Since the aeration is difficult to control in practical conditions, we assumed that the amendment of NaOH can not be used to reduce the level of produced sulphate in freshwater sediments.