过氧化钙(CaO2)联合生物炭对河道底泥的修复

底泥内源污染是导致河道黑臭反复的主要因素.为防止河道黑臭现象反复,以无锡市滨湖区某一河道为实验地点,采用CaO_2联合生物炭原位覆盖技术修复黑臭河道底泥,研究了该技术对泥水水质、底泥酸挥发性硫化物(AVS)和磷形态以及微生物的影响,探究该技术对黑臭底泥修复效果.结果表明, CaO_2联合生物炭覆盖可显著提高泥水体系溶解氧(DO)浓度和氧化还原电位(ORP),其中上覆水DO浓度和ORP分别保持在2 mg·L~(-1)和50 mV以上.间隙水氨氮(NH~+_4-N)、化学需氧量(COD)和总磷(TP)去除率分别达到了43.40%、 41.18%和50.97%.底泥AVS去除率达到了37.03%,高通量测序表明,底泥厌氧微生物相对丰度明显降低,出现热单胞菌属(Thermomonas)、Dechloromonas、变形菌属(Proteus hauser)、脱硫微菌属(Desulfomicrobium)和硫杆菌属(Thiobacillus)等脱氮除硫菌群.底泥中磷转化为稳定的铁铝结合态磷和钙结合态磷.因此,CaO_2联合生物炭原位覆盖对黑臭底泥具有良好的修复作用.

Restoration of River Sediment by Calcium Peroxide(CaO2) Combined with Biochar

The internal source pollution of sediment is the main factor leading to the repetition of black-odorous river channels. In order to prevent this situation, a river channel in the Binhu District of Wuxi City was used as an experimental site. In-situ CaO₂ combined with a biochar covering technology was used to repair the black odorous river sediment in this channel. The effects of this technology on the quality of mud water, sedimentary volatile sulfide (AVS) and phosphorus forms, microorganisms, and restoration of black odorous sediment were investigated. The results showed that CaO₂ combined with biochar coverage could significantly increase the dissolved oxygen (DO) concentration and redox potential (ORP) of the muddy water system. The DO concentration and ORP in the overlying water were maintained above 2 mg·L^-1 and 50 mV, respectively. The removal rates of interstitial water ammonia-nitrogen (NH₄⁺-N), chemical oxygen demand (COD), and total phosphorus (TP) reached 43.40%, 41.18%, and 50.97%, respectively. The removal rate of AVS in the sediment reached 37.03%. The high-throughput sequencing showed that the relative abundance of anaerobic microorganisms in the sediment was significantly reduced, and that nitrogen and sulfur removal microorganisms appeared (e.g., Thermomonas, Dechloromonas, Proteus hauser, Desulfomicrobium, and Thiobacillus). Phosphorus in the sediment was converted into Fe/Al-P and Ca-P. Therefore, in-situ CaO₂ combined with biochar coverage had a good repairing effect on black odorous sediment.