Advanced Water Management Centre, The University of Queensland, QLD, Australia.
Water Res. 2013 Sep 1;47(13):4331-9. doi: 10.1016/j.watres.2013.05.024. Epub 2013 May 24.
Intermittent dosing of free nitrous acid (FNA), with or without the simultaneous dosing of hydrogen peroxide, is a new strategy developed recently for the control of sulfide production in sewers. Six-month field trials have been carried out in a rising main sewer in Australia (150 mm in diameter and 1080 m in length) to evaluate the performance of the strategy that was previously demonstrated in laboratory studies. In each trial, FNA was dosed at a pumping station for a period of 8 or 24 h, some with simultaneous hydrogen peroxide dosing. The sulfide control effectiveness was monitored by measuring, on-line, the dissolved sulfide concentration at a downstream location of the pipeline (828 m from the pumping station) and the gaseous H2S concentration at the discharge manhole. Effective sulfide control was achieved in all nine consecutive trials, with sulfide production reduced by more than 80% in 10 days following each dose. Later trials achieved better control efficiency than the first few trials possibly due to the disrupting effects of FNA on sewer biofilms. This suggests that an initial strong dose (more chemical consumption) followed by maintenance dosing (less chemical consumption) could be a very cost-effective way to achieve consistent control efficiency. It was also found that heavy rainfall slowed the recovery of sulfide production after dosing, likely due to the dilution effects and reduced retention time. Overall, intermittent dose of FNA or FNA in combination with H2O2 was successfully demonstrated to be a cost-effective method for sulfide control in rising main sewers.
间歇性投加游离亚硝酸（FNA），同时或不与过氧化氢同时投加，是最近开发的一种控制污水管道中硫化物生成的新策略。在澳大利亚的一条上升污水主管道（直径 150 毫米，长 1080 米）中进行了为期六个月的现场试验，以评估该策略在实验室研究中之前证明的性能。在每次试验中，FNA 在泵站投加 8 或 24 小时，有些同时投加过氧化氢。通过在线测量管道下游位置（距泵站 828 米）的溶解硫化物浓度和排放井中的气态 H2S 浓度，监测硫化物控制效果。在所有九次连续试验中均实现了有效的硫化物控制，每次投加后 10 天内硫化物生成减少了 80%以上。后期试验的控制效率优于前几次试验，可能是由于 FNA 对污水生物膜的破坏作用。这表明，初始强剂量（更多的化学消耗）后进行维持剂量（较少的化学消耗）可能是实现一致控制效率的非常经济有效的方法。还发现，强降雨会减缓投加后硫化物生成的恢复速度，可能是由于稀释作用和停留时间缩短。总的来说，间歇性投加 FNA 或 FNA 与 H2O2 被成功证明是上升污水主管道中控制硫化物的一种经济有效的方法。
