|
The water waters Tubificidae large number of breeding breeding migration movement into the water treatment plant into the water supply pipe, and then because of its strong ability to penetrate and clean water disinfectant strong tolerated, can penetrate the entire water purification process network, causing the decline of public confidence in the water quality. Effectively protect the quality of water supply security, the Tubificidae pollution risk prediction and control work is imperative. This paper laboratory to simulate the migration and breeding of Tubificidae in the water source waters, the Tubificidae migration movement pattern and environmental parameters of temperature, DO, sediment properties impact on the of Tubificidae movement migration, and influences of temperature and DO flutter earthworm breeding, based on the pilot system Tubificidae in the migration of the sand filter distribution study, its purpose is to provide a theoretical basis for the waterworks Tubificidae outbreak forecasting and risk control. The research results obtained are as follows: (1) migration is The Tubificidae one of the primary means to expand the distribution of its population, according to the migration location can be divided into the mud inside the shallow migration, mud deep migration and zooplankton migrate three categories. Temperature, DO and sediment character can Tubificidae the sediment migration impact. Temperature of 22 ℃, dissolved oxygen 8mg / L more appropriate Tubificidae growth, total mobility Tubificidae smaller temperature is raised or lowered, and the reduction of dissolved oxygen will cause the Tubificidae migration scale increase. Sediment migration is achieved by changing the the Tubificidae food source; (2) zooplankton migration is the direct cause of the waterworks Tubificidae pollution. Planktonic migration mainly caused by the scouring action of the water, while the temperature and DO will impact on planktonic migration, the experimental conditions, the flow rate greater than 5.55mm / s Tubificidae can occur planktonic migration, and planktonic mobility with velocity to increases; increase in temperature and dissolved oxygen can cause reduced planktonic mobility; (3) the migration and distribution of Tubificidae in the sand filter sand filter can effectively intercept Tubificidae, its blocking effect filter grain diameter and length Tubificidae, the larger the filter size, the Tubificidae smaller body length, the intercept effect is worse; filter running conditions will impact Tubificidae in filter migration distribution from Tubificidae pollution control perspective, the filtration rate should not exceed 11.1m / h, filtration cycle should not exceed 12h guarantee the backwash strength is the key to achieve the Tubificidae completely remove the backwash intensity of 25L / s · m2 Tubificidae go The removal rate of up to 97.7%; (4) an increase in temperature can significantly improve the innate capacity for increase Tubificidae shorten the the populations doubling time, under the experimental conditions, a temperature of 10 ° C, 20 ° C and 30 ℃, Tubificidae population doubling time were 38.6d, 18.0d and 8.6d, shows that the temperature rise can promote the Tubificidae the growth breeding; reduce the DO concentration by 8mg / L to 5mg / L, flutter earthworm population doubling time can be 21.7d 11.2d improve to continue reduce DO concentration to lmg / L, the population doubling time only increased from 21.7d to 25.8d, that Tubificidae low dissolved oxygen conditions still a lot of growth and reproduction. These studies have shown that in large quantities in the polluted water of low dissolved oxygen due to quiver the earthworm special living habits, growth and reproduction, and by water erosion caused by zooplankton migrate into the water treatment plant, leading to the risk of contamination of the Tubificidae, including temperature and dissolved oxygen chatter the earthworm growth and reproduction and migration will have a significant impact; sand filter, part Tubificidae Tubificidae completely intercept will penetrate the filter into the water supply system, and sand filtration operating conditions will affect Tubificidae intercept effect can not be achieved. The results of this study can provide the theoretical basis and technical support for waterworks flutter the earthworm pollution risk prediction and control.
|