In this study, the hydrologic investigation for the Fengshan River were conducted and the recent water monitoring data of the Fengshan River were also collected and evaluated. The water quality model [Water Quality Analysis Simulation Program (WASP)] (developed by US EPA) was applied for the water quality modelling of the Fengshan River. The modelling results were used for pollutant loading calculation, river water quality simulation, and pollution control strategies development. The electric conductivity was applied for the model calibration. Results show that the simulated results matched with the observed data very well. The calibrated WASP model was used for dissolved oxygen (DO), biochemical oxygen demand (BOD), and ammonia nitrogen (NH3-N) simulation. Results from the box-and-whisker plot analyses also verified that the established model is appropriate for the water quality modelling. Results from the water quality modelling show that the Futian to Dadong Bridge (Fengshan River section) had a more significant impact on the Upstream of Fengshan River water quality compared with the Other section. The contributions of BOD and NH3-N from Fengshan and shantzaiding Trench were about 20%. Remedial strategies for the Fengshan River water from short-term to long-term were developed. The completion of the Futian to Dadong Bridge section to remove 20% of the point source pollution can serve as a short-term goal while 30–50% of pollutant removal by natural treatment systems may serve as a mid-term and long-term strategy. The Fengshan Sewage plant discharges water use of recycled water simulation results show that the downstream ammonia nitrogen concentration significantly increased, In the future, recommend Environmental Protection Bureau (EPB) have to regularly monitor Fengshan Sewage plant discharges water upstream and downstream of ammonia nitrogen concentration changes, to protect Fengshan River water quality and provide EPB water quality evaluation and emergency response plan. Through the analysis of molecular biotechnology it was found that Fengshan River were collected from the upper, mid, and downstream sections have many intrinsic microbial and abundance of microflora. In addition, the sequencing result showed that PAEs and PAHs could be degraded by the following strains: Flavobacterium sp., Bacillus sp., Pseudomonas sp., Mycobacterium sp., Rhodococcus sp. etc. The above findings confirm that Fengshan River intrinsic microbial could be a viable remediation technology in the future to treat PAEs and PAHs contaminated river sediment. In this study, the sediment samples from the Fengshan River were collected from the upper, mid, and downstream sections to evaluate the heavy metal and organic compound distributions in the sediments. Sediment investigation results show that the organic compound concentrations were lower than the lower level of sediment quality. Compared to the effects range low (ERL) values established by National Oceanic and Atmospheric Administration (NOAA), polycyclic aromatic hydrocarbons (PAHs) had insignificant impact on the aquatics. However, sediment contained higher concentrations of Ni, Zn, As, and Hg, which were higher than the lower level of the sediment quality. Moreover, Ni, As, Zn, and Hg concentrations were close to the effect range median (ERM) indicating the heavy metals had some impact on the aquatics. Thus, the sediment quality needs to be further investigated and the results can be used to develop the sediment management strategies.

Water Quality Analysis Simulation Program (WASP)