Environmental Dredging Technology Influence Factor Analysis And Process Optimization

At present, the river and lake sediment pollution management is faced with severe situation, especially in the Yangtze river three gorges channel backwater, such as sediment flow moving rate, increase the amount of sediment reservoir, the point source pollution and non-point source pollution are make the contaminants entering the reservoir area. Over time, the pollutions and silt are make the common effects on the Yangtze river three gorges channel backwater. To this end, Three Gorges Reservoir and environmental problem are urgent need to resolved. The traditional dredging equipment structure have poor environmental benefit problems.Paper research from the traditional dredging equipment structure, combining the passivating agent and improved equipment, in order to find a suitable dredging mode for the Yangtze river three gorges channel backwater.Paper system elaborated the mechanism deactivator, the suitable of passivating agents, the suitable dredging equipment operating parameters.The main conclusions are summarized as follows:1)The amount of PAC passivating agent, calcium and iron salts deactivators have a certain degree of influence to the release of the pollutants in sediment PAC passivation dosage for 2g/kg,4g/kg,6g/kg. The pollutant COD release amount is 37.42%,43.87%, 41.94%,respectively, the lowest emission of pollutants can be as low as 97mg/L,87mg/L, 91mg/L.Passivatting agent dosage increased sediment pollutant emission suppression COD increase was not linear, but in the passivating agent dosage for 4g lowest, mainly because of the limited degree of hydrolysis of aluminum salts, iron salts oxidative makers its COD emission at the lowest 6g/kg sediment dosage, dosage of calcium passivating agent was 12g/kg, the lowest sediment COD emission of pollutants. Because of the PAC, The pollutant TN release amount is 29.36%,42.55%,23.38%, calcium. The pollutant TN release amount is 30.90%,43.44%,23.66%. iron salt deactivators passivation efficiency at three dosage of 21.54%,41.90%,24.66%.For TP PAC passivating agent passivation efficiency at the three dosage respectively to 71.15%,82.69%,76.92%, calcium deactivators passivation efficiency at three dosage is 61.71%, 76.60%,70.21%. For ammonia three kinds of passivating agent showed no significant effect of passivation.2) Reamer traverse speed and speed have a certain impact on the dredged mud density, which greatly affect the cutter traversing speed of dredged mud concentration. Analysis concluded that in order to improve the efficiency of dredging equipment reamer for the purpose of speed and traverse speed was 40r/min and 200mm/min.3) In four different devices reamer that is general engineering, combined with the general increase cover Reamer, green spiral reamer, plus cover environmental spiral reamer with PAC passivating agent and passivating agent after calcium sediment are being dredging simulation. As a result, after joining the PAC dredging passivating agent, when the pollutant concentration in overlying water stable, COD emission of environmental pollutant plus cover dredging reamer after each ordinary, ordinary plus cover reamer, environmental reamer To small 24mg/L, 15mg/L,10mg/L,TN spiral reamer plus environmental contaminants than the other three cover types reamer release of TN decreased by 7.46mg/L,2.41mg/L,3.58mg/L, TP plus cover environmental pollutant emissions after dredging reamer were common, ordinary plus cover reamer,reamer environmental smaller 0.53mg/L,0.33mg/L,0.40mg/L, environmental protection NH3-N release of pollutants after dredging plus cover reamer reamer were ordinary, ordinary plus cover reamers, reamer environmental smaller 1.47mg/L,1.10 mg/L,0.86mg/L. Environmental dredging plus cover reamer analog COD contaminants accumulated passivating agent after adding calcium release was 131mg/L, respectively, compared with normal reamers and cover the state reduced its plus 22mg/L,16mg/L, environmental protection plus cover reamer passivating agent after adding calcium nitrate TP release than the other three forms of reamer equipment reduced by 0.33mg/L,0.25mg/L,0.31mg/L, plus cover environmental dredging reamer TN respectively, after the release of pollutants ordinary reamer, plus cover ordinary reamers reamer environmental smaller 7.38mg/L,4.10mg/L,2.86mg/L, NH3-N pollution environmental protection plus cover ordinary reamers, reamer environmental smaller 0.55mg/L,0.52mg/L,0.13mg/L.Data analysis from this study, the use of environmentally friendly dredging plus cover spiral reamer and PAC passivating agent combination of both dredging technology solutions for the implementation of the program of environmental dredging.This study backwater area of the Three Gorges waterway dredging silt sediment environmental program provides a theoretical basis and technical support, research results have important theoretical and pratical value.