practical, economical, reasonable water treatment process is of great significance to
improve the people's quality life as well as the pollution prevention of the park lake.
13 typical lakes water of the 12 parks in Shanghai were selected as the objects of
study, analysed the space time variety rule of the different quality indicators of the lake
water and water pollution characteristics by the monitoring results for each lake. The
improved comprehensive water quality identification index method has been used to
evaluated the water pollution situation for each lake and the comprehensive
eutropHication identification index method has been used to assess the eutropHication
status for the various lakes. A/O compound BAF process has been used on the
experimental study for the eutropHication water of the lake park based on the analysis
of the water quality characteristics and eutropHication evaluation, the main conclusions
are as follows:
The change rule of the various pollution indicators about turbidity, total
pHospHorus, total nitrogen, ammonia nitrogen, chlorophyll a concentration is a more
consistent, the concentration of the pollution indicators of the Quyang park lake was
greater than other park lakes and the rangeability of the concentration varied
significantly in different months. Nitrogen, pHospHorus probably were the main
influence factors made the Tianshan Park, Changfeng Park and Songnan greater Park
lake eutropHia. Significantly positive correlation was found between chlorophyll a
concentration and ammonia nitrogen in Tianshan Park and Changfeng Park lakes.
The improved comprehensive water quality identification index method was used
in the evaluation of the park lake water pollution, the results showed that jinqiao park
lake water quality was the best, the water quality were in class Ⅲ and class Ⅳ
level.most of the other park lakes’ water quality were in class Ⅴ or inferior class Ⅴ
level. Quyang park lake was the most highly contaminated, the water quality was in
inferior class Ⅴ level and sometimes black-odor pHenomenon occurred during the
monitoring period. The pollution of the park lakes in summer and autumn was generally
more serious than spring and winter, the water quality management should be
strengthen. The main pollution factors of the park lakes were COD and TN. The
eutropHication assessment results showed that only Jinqiao Park and People's Park lake
water were in mesotropHic category during the monitoring period, there were different
degrees eutropHication in different months in the other park lakes, most of the
eutropHication pHenomenon of the park lakes appeared in summer.
BAF experimental results showed that: when the A/O volume ratio of the BAF was
in 1:1.08, hydraulic loading was in 1.1 m3/m2h, and the gas-water ratio was in 2.5:1,
BAF for the average removal rate of COD、NH4+-N、TN、TP、turbidity reached 62.6%,
96.02%, 46.1%, 45.7%, 91.84%, respectively. The concentration of effluent
COD、NH4+-N could reach class Ⅳ water standard. Increasing the effluent reflux ratio
of the BAF has little impact for the removal rate of COD, ammonia, turbidity, the
removal rate of TP decreased, but the removal rate of TN increased significantly, when
the reflux ratio was 1:1, the total nitrogen concentration of influent water between
4.56mg/L~6.31 mg/L, the total nitrogen concentration of effluent water was maintained
II