Phytoplankton in an urban river replenished by reclaimed water: Features, influential factors and simulation
Xuemin Lv, Jiao Zhang, Peng Liang, Xiaoyuan Zhang, Kai Yang, Xia Huang
Abstract
Algal bloom control in rivers replenished by reclaimed water has drawn attentions. Aiming at precisely simulating and forecasting the algal density, a typical downstream urban river replenished by reclaimed water was monitored and investigated in aspects of the water quality, algal density, algal community. Parameters of water quality revealed the typical feature of reclaimed water, with high concentration of nitrogen. Algal density dropped gradually from spring to the late autumn, indicating that spring was of high risk of algal bloom. Chlorophyta and Bacillariophyta were identified as the dominant phyla, and Chlorella (belonged to Chlorophyta), Cyclotella (belonged to Bacillariophyta) and Coscinodiscus (belonged to Bacillariophyta) were the dominant species. Both statistical analysis and model simulation revealed that light intensity, nitrogen and metal ions were the influential factors of algal growth in the river. Simulation of the change of algal density using AutoRegressive Integrated Moving Average (ARIMA) model (0, 0, 15) was effective with all the simulated value in the 95% confidence interval, making it feasible to the practical forecast of algal bloom in urban rivers, especially those which are replenished by reclaimed water.