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| Rapid treatment of suspended solids with small size in tunnel wastewater by micro-flocculation method |
| CHAI Baohong1, FANG Bulei1, WANG Yan1, DING Haohui2*
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1. CCCC Fourth Highway Engineering Co., Ltd., Beijing 100022, China;
2. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China |
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Abstract In order to efficiently treat the suspended solids with small size in the wastewater discharged during tunnel construction in karst area, the pollutants in the tunnel construction wastewater from Guilin to Liucheng Expressway were analyzed. Based on the concept of micro-flocculation filtration method, suspended solids with small size in wastewater were treated by coagulation-filtration process.The results showed that the main pollutants in the tunnel sewage were suspended solids and hydrogen ion concentration. Polymericferric sulfate silicatewas used as green flocculant, the flocculated wastewater was directly filtered, which could effectively remove at least 65% of the suspended solids with small size in water. For the wastewater with suspended solids content of 25, 50, 100 mg/L, the removal rates of suspended solids are 65.52%~68.47%, 79.06%~80.91%, and 85.19%~88.85%, when the precipitation time in 0~5 minutes, respectively.It can be seen that the precipitation process has little effect on the removal of suspended solids with small size. Therefore, it is suggested to cancel the precipitation process in wastewater treatment and directly adopt the flocculation-filtration process to efficiently treat the suspended solids with small size in the tunnel sewage.
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Received: 17 May 2021
Published: 20 December 2021
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