Ke Fan

Low concentration of phosphorus removal in waters with CaO 2

Aiming at the advanced purification of low concentration of phosphorus in natural water,the adsorption of phosphate by CaO2 was studied using the models of adsorption kinetics and adsorption isotherm,and the influence of different operating parameters on the phosphorus removal was investigated. The results showed that:( 1) The experimental data for the process of phosphate uptake onto CaO2 fit the Langmuir isotherm mode,and the maximum adsorption capacity was 381. 7 mg / g( 25℃).( 2) Thermodynamic parameters in the process of phosphorus removal are ΔG0 0 and ΔH0 0,while the process was a spontaneous exothermic one.( 3) The adsorption performance of CaO2 was evaluated by the pseudo-second-order reaction rate equation,when the adsorption rate increased with the increasing concentration of phosphate in the solution,and the adsorptive reaction reached equilibrium in 4 minutes.( 4) The optimized effect of phosphorus removal was obtained at p H = 8.( 5) Among the high concentrations of coexisting anions,the CO2-3expressed the greatest influence on phosphorus removal of CaO2 and could make the adsorption capacity reduce 14. 7% under the concentration of 10 times.

Laboratory research on the contaminants release during the anaerobic decomposition of high-density cyanobacteria

The anaerobic decomposition of high-density cyanobacteria and the kinetics of contaminants release were investigated based on a set of batch tests in this study.The results showed that the degradation rates of chlorophyll-a(Chl.a were 0.074,0.133,and 0.081 d-1,respectively,at different cyanobacterial densities of 2.23×1012,1.19×1013 and 4.47×1013 cells/L,respectively.The chemical oxygen demand increased while the UV254 value increased initially and then decreased,suggesting that the release of organic compounds increased,but the molecules of which were reduced gradually during the degraded process.Accordingly,the pH of incubation solution remained acidic and the conductance increased,up to 949 μS/cm.The decomposition of cyanobacteria resulted in a high release of nitrogen and phosphorus.Moreover,dissolved organic nitrogen was degraded gradually into inorganic nitrogen form,in which the amount of ammonia nitrogen accounts for 90%.The results demonstrate that the anaerobic decomposition of high-density cyanobacteria can release a large amount of organic compounds and nutrients into water,furthermore the release of contaminants increases with the increasing density of cyanobacteria.Therefore,to avoid high-density cyanobacteria deteriorating water quality and even threatening drinking water safety,we need to remove cyanobacteria timely when algal bloom occurs in the lake which is served as water resource.

Analysis of pollution characteristics and first flush effect in rainfall runoff in separate storm sewer system in upstream of Tangxi River,Chaohu Catchment

Understanding the runoff water quality and first flush effects can guide the management of urban runoff pollution. Six rainfall events were monitored and event mean concentration(EMC) and event pollutant loads per unit area(EPL) were calculated in the upstreams of Tangxi River. The M(V) curve was used to show the first flush effects. The results showed that the EMC of sus⁃ pended solids(SS), chemical oxygen demand(CODCr ) and total phosphorous( TP) were relatively large in rainfall runoff. The EMC of SS has the most significant fluctuations. There was a positive correlation beween total nitrogen(TN), TP, CODCr and SS. The EMC of TN was negatively correlated with the rainfall. The EPL of runoff water pollution has a positive correlation with the rainfall characteristics. Approximately 10.38 t TN, 2.29 t TP, 1022.43 t SS, 161.70 t CODCr and 5.18 t NH3 ⁃N were input into the Lake Chaohu via runoffs in June, July, and August, 2015.Rainfall and antecedent dry weather period were the main influen⁃ cing factors of the urban storm runoff pollution. Five kinds of pollutants had their own first flush effects, employing the FF50>50 as

Aerobic enhanced degradation of organic detritus of lacustrine sediments

The organic detritus in sediments of the Lake Chaohu were taken as research subject,based on measured total organic carbon in organic detritus. Research was undertaken on the organic detritus of biodegradability and the results of aerobic enhanced degradation of organic detritus,and the degradation effects of organic detritus on different concentrations of organic detritus and aeration rates. The results show the organic detritus has high biodegradability. In about 30 h,reaction reached equilibrium concentration,total removal rate was 50. 69%,and the degradation rate constant K25was 0. 19 h- 1. The concentration of organic detritus and aeration rates have impacts on degradation effect. The method of aerobic enhanced degradation of organic detritus in sediments of the lake is better than traditional method,and provides a new way for the prevention and treatment of black and odorous water.

In-situ model experiment on purification of polluted river water into lake based on micro-aerated ecological floating bed

Aiming at the problem of black-odor, oxygen deficiency and ammonia-nitrogen pollution of polluted rivers, a new type of ecological floating bed—micro-aerated ecological floating bed was developed, which combined biofilm packing, floating aquatic macrophyte and auxiliary aeration device. The purification efficiency of the polluted river water was studied by the model experiment in the outlet of Daqing River. The results showed when the hydraulic loading was 1500mm/d, the mean removal efficiencies of total nitrogen, ammonia nitrogen, total phosphorus and phosphate were 81.1%, 91.3%, 72.7% and 92.5%, respectively. Additionally, the floating bed showed better removal effect on organic matters. The cost of micro-aerated system to treat 1m3 of polluted river water was only 0.007 Yuan. The micro-aerated ecological floating bed ran steadily, had a high efficiency of pollutants removal and low energy consumption. It was suitable for the environment of flowing water, which could be used in polluted river and estuary.