CaO_2不同投加方式对黑臭河道底泥内源磷释放抑制作用

Inhibition of Internal Phosphorus Release in the Black-Odor Channel Under Different Adding Methods of CaO_2

以S市某黑臭河道底泥和上覆水为研究材料,研究了CaO_2在3种不同投加方式下对内源磷释放的抑制效果.结果表明CaO_2在3种投加方式下,均导致上覆水中pH和DO有所增加.注射条件下,上覆水DO浓度明显低于覆盖,说明注射确实延缓了CaO_2的氧化速度,有利于创造底泥微氧化环境.CaO_2覆盖和注射条件下,上覆水中TP和DIP浓度以及变化趋势基本一致,均明显低于混匀条件.但是,覆盖条件下,间隙水中DIP浓度最高,达到注射条件下的120.33~142.18倍.相反,注射条件下,间隙水中DIP浓度最低,并且上覆水中DIP浓度也较低,说明注射条件下CaO_2对内源磷的释放确有抑制作用,这与其创造的微氧化环境密切相关.底泥中不同形态磷数量分布也证实了这一点.投加CaO_2加快了有机磷的矿化速度,铁铝结合态磷和钙结合态磷也明显增加,使得内源磷持留能力增强.

The inhibition of sedimentary phosphorus（P） was investigated under the CaO2 with 3 addition ways. The overlying water and sediments came from a black-odor channel in S City. The results showed that the value of pH and DO in the overlying water increased under the 3 addition ways of CaO2. Under the condition of injection, the DO concentration of the overlying water was lower than that of the covering condition, which indicated that the injection could delay the oxidation of CaO2 and be favor of creating the micro-oxidation environment in the sediment. The concentrations and the trend of TP and DIP in the overlying water were similar under the injection and covering, which were lower than that in the mixing condition. However, under the covering condition, the DIP concentration in the pore water was the highest, reaching up to 120.33-142.18 times, compared with the injection condition. Noticeably, the DIP in the pore water and the overlying water was lower, indicating that the addition of CaO2 could inhibit the release of sedimentary P. This was attributed to the micro-oxidation environment. The sedimentary P fractions also confirmed this. The explanation may be that the addition of CaO2 accelerated the mineralization of organophosphate and the formation of Fe-Al/P and Ca-P, which enhanced the retention of sedimentary P.