输水工程中沼蛤的附着特性

沼蛤(Limnoperna fortunei)容易入侵输水管道聚团附着,增加输水阻力,引起管壁腐蚀,污染水质。该文旨在研究沼蛤在输水管道中的附着污损特性并提出有效防治其附着污损的思路。以遭受沼蛤污损的深圳东江水源工程作为研究基地,对工程的水源河流东江、西枝江中沼蛤栖息特性进行野外调查,对工程输水管线中沼蛤附着及造成的生物污损开展调查,并结合沼蛤足丝抵抗水流冲刷试验、足丝附着力试验及沼蛤对不同材料的附着试验,研究了沼蛤的附着特性。管线调查结果表明:输水管道中沼蛤的附着密度随距取水口距离的增加而衰减。且沼蛤高密度区主要集中在取水口后1km范围内水流流速在0.4—0.9m/s之间的箱涵壁面上。足丝附着力试验结果表明:沼蛤用于附着的足丝具有一定的强度,且足丝直径越大,根数越多,附着力也越大,最大附着力约为20N;足丝抵抗水流冲刷试验结果表明水流流速过大会使沼蛤足丝断裂脱落,最大脱落流速约为2.2m/s。同时,沼蛤的附着对材料具有一定的偏好性,相比于地垫和防护网,竹网及粗布是沼蛤喜好附着的材料。

Attachment characteristics of golden mussels (Limnoperna fortunei) in water transport projects

Golden mussels(Limnoperna fortunei) easily invade into water transfer pipelines and attach on pipe walls with extremely high densities,increasing the flow resistance and causing corrosion and water pollution.This study analyzes the characteristics of golden mussel attachment and biofouling on pipe walls to develop biofouling prevention strategies in water transfer projects.Experiments were conducted in the East River Water Source Project,whose pipelines suffer serious golden mussel biofouling.Field investigations were conducted in the East and Xizhi rivers,which are the water source rivers for the project to study the characteristics of golden mussel attachment in natural habitats.Pipeline investigations were performed in the project to study golden mussel attachment and biofouling on pipe walls.The experiments measured the attachment force,splitting velocity,and material preference for golden mussel attachment.The results show that the golden mussel attachment density on pipe walls decreases with increasing distance from the pipeline entrance.The highest attachment density is concentrated within 1 km from the entrance and with flow velocities of 0.4~0.9 m/s.The results show that the unprimitive byssus of the golden mussel is very strong.The larger byssus diameters and the more byssus create stronger attachment forces.The maximum attachment force was about 20 N.However,the byssus can be broken by flushing flow with velocities exceeding the splitting velocity of about 2.2 m/s.The golden mussels preferred bamboo and coarse cloth to plastic materials and protective screening.