| A large number of industrial and domestic wastewater discharged into the river,and all of this made urban river water blackening and stink and becomed a serious threate to ecological security of Dianchi Lake.This paper based on the investigation of the Laoyunliang River,analyzed the water pollution characteristics and habitat characteristics.Four experimental devices for simulating river water way was constructed,to explore the restoration Laoyunliang River basal habitat with gravel and polymer filler."Basement material" and "Basement material + polymer filler" were compared by their ability to restoration on river habitat,which can provide technical support to the habitat restoration on Laoyunliang River.Main results are as follows:(1)Laoyunliang River is 11.3 kilometers long,its main function is flood control and drainage.Most of upstream channel has hardened,sewage collection system is not perfect,and too much untreated wastewater was drained into it.It lost self-purification ability and the ecological function.Composed of garbage and sewage sediment is becoming thicker.0.5 meters to 0.8 meters thick sediment deposit in the bottom of river.The statistics of runoff showed that from May to October runoff accounted for about 74%of all year,from November to the next April water quantity is less and runoff accounts for only about 26%of all year.The water quality of Laoyunliang River is worse than Grade V and transported great deal of COD,nitrogen and phosphorus to Dianchi Lake.Laoyunliang River habitat was poor.The water quality in the upstream and midstream was poor.Run off was not stable,run off in downstream was bigger than upstream and midstream.Downstream habitat was better than upstream and midstream.(2)The results of polymer filler selection experiments showed that 3 experimental facility which filled polymer filler showed better removal efficiency.The average removal rates of COD from D2 to D4 were 47.5%,45.18%and 46.94%and the average removal rates of ammonia nitrogen were 42.2%,38.07%and 51.72%.But all experimental facilities had lower removal efficiency of total phosphorus,the highest removal rate is 11.63%achieved by D2.D2 got highest removal rate for total nitrogen(20.21%).D2 showed best purification performance.Because,D2 filled with combined polymer filler which own the largest ratio surface area,was liable to microbial adsorption.So D2 was selected into the next work.In the condition of 50 litters per day,the removal rate of total phosphorus was worse than before,removal rate reached to 8.51%,in the condition of 25 litters per day.The removal rate of COD was better than before(64.26%)and the removal rate of total nitrogen is 18.85%.The biodiversity of D2 is greatly increased by high-throughput sequencing analysis.ACE diversity index increased from 754.1 to 2091.9;Chaol diversity index increased from 574 to 1811.That habitat of experimental facility D2 has improved,it is more fit for for the growth of microbial.(3)Choose the wooden cage to be the structured experiment vessel and additional carbon source,and check its impact on water quality.Found that the wooden cage would release carbon source and nitrogen and phosphorus,can caused certain influence to the water quality,but releasing time of nitrogen and phosphorus were shorter than carbon source's.Before using natural materials,we should determination the chemical composition of the material,determine its release regularity,and check the potential harm.Temperature made a great influence on nitrogen and phosphorus removal rate.Low temperature influenced the activity of microorganisms,caused the removal rate to drop. |
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