ZHUQi,LIDa-peng,LIUSong-qi.Fly Ash in Coordination with Cement and CaO2 to Solidify Sediment and Its Performance for Controlling Endogenous Pollution[J].China Water & Wastewater,2024,40(7):105-112.
Fly Ash in Coordination with Cement and CaO2 to Solidify Sediment and Its Performance for Controlling Endogenous Pollution
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第40卷
Number:
第7期
Page:
105-112
Column:
Date of publication:
2024-04-01
- Keywords:
- sediment curing technology; fly ash; cement; calcium peroxide; endogenous pollution; nitrogen and phosphorus release
- Abstract:
- This paper solidified the sediment from urban polluted river by mixing different proportions of single curing agent (cement) and compound curing agent (cement and CaO2), and then detected the unconfined compression strength of the solidified sediment and the release of nitrogen and phosphorus from the sediment under static and rainfall erosion conditions. On this basis, the dosages of the two groups with better curing performances (50% cement and 50% cement with 10% CaO2) were selected respectively, and different dosages of fly ash were further added to explore the performance of cement and CaO2 in coordination with fly ash for sediment solidification. Both the cement curing alone and cement and CaO2 curing solidified the sediment into blocks and showed strong compression resistance, significantly reduced the release of dissolved inorganic phosphorus (DIP) from the sediment to the overlying water, and demonstrated a good curing performance under static and rainfall erosion conditions. In addition, cement and CaO2 changed the form of phosphorus in the sediment. However, cement did not promote the conversion of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP), while CaO2 promoted the conversion of NAIP to AP. The addition of fly ash further improved the curing performance of cement and CaO2, in which the optimal proportion of curing agent was cement, CaO2 and fly ash of 5∶1∶2. Compared with the control group, the removal rates of ammonia nitrogen and DIP in overlying water after the solidification of the sediment were 86.33% and 90.5% in the later period of the experiment (13-20 days). The collaborative curing of cement, CaO2 and fly ash effectively inhibited the release of endogenous nitrogen and phosphorus from the sediment and reduced the secondary pollution of the sediment to the environment.
Last Update:
2024-04-01