Effect of Algae Deposition Formed by PAC Flocculation on Nutrient Release in Water-sediment System
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第36卷
Number:
7 7
Page:
78-83
Column:
Date of publication:
2020-04-01
- Keywords:
- PAC flocculation; algae deposition; overlying water quality; sediment composition; nutrient release
- Abstract:
- Polyaluminium chloride (PAC) flocculation is an efficient approach to reduce algae density in water, but the effect of the algae deposition formed by PAC flocculation on nutrient release in the water-sediment system is rarely reported. By monitoring the changes of overlying water quality and sediment composition when different amounts of flocculated algae were deposited on a certain amount of sediment surface, the effects of algae deposition formed by PAC flocculation on water quality and sediment endogenous release were investigated. Algae deposition could significantly increase the nitrogen release from sediment to the overlying water. When the dry mass ratios of sediment to algae were 167.2, 83.6 and 41.8, the mean concentrations of NH+4 - N in the overlying water of the reactor were 2.86 times, 2.42 times and 1.43 times of the control reactor (CK), and the corresponding mean concentrations of TN were 2.06 times, 1.66 times and 1.09 times of CK, respectively. Furthermore, the algae deposition could promote denitrification at the watersediment interface, and the effect was negatively correlated with algae amount. However, the algae deposition played an active role in controlling the phosphorus release from the sediment. The mean concentrations of TP and PO3-4 - P in the overlying water of CK were 0.35 mg/L and 0.22 mg/L during the experiment. However, all the corresponding values in the algae deposition reactors were lower than 0.05 mg/L and 0.03 mg/L, and the lower concentration of phosphorus would be achieved with the higher algae deposition amount.
Last Update:
2020-04-01