Research On The Different Mix Of Water Quality And The Pattern Of Algae Growth In Shibianyu Reservoir

Xi’an reservoir of Shibianyu at the state of eutrophication, this resulted that thedeterioration of water quality, algal blooms. It is a major problem to be solved. Thethesis take a period of one year on-site monitoring in Shibianyu reservoir, to analysis ofthe different mix of reservoir water quality, algal growth and algal toxin productionconditions, the anaerobic zone analysis at different distribution water, algae controlscheme, to provide a theoretical basis for the water supply and pumping aeration algaecontrol technology. The main conclusions are as follows:(1) Shibianyu reservoir is divided into four periods. The form of hierarchical at endof March to July; The stable stratificationat at the end of July to the end of September;The destruction of stratification at October to November; The water body completelymixed at the end of November to March. The maximum ammonia at bottom waterreached1.46mg/L, it is the upper body of water seven times. The highest TN valuereached4.03mg/L, beyond the standard Class III surface water4times. TP, iron,manganese concentrations up to0.2mg/L,0.2mg/L,1.11mg/L, the content ofphosphorus, manganese are4times,10times to surface water Class III. The maximumsurface water pH is10.56, while the underlying conductivity reaches a maximum of243μS/cm at the periods of stably stratified in Shibianyu reservoir. The other threeperiodsother indicators of surface water to meet Class III s tandards in addition to thetotal nitrogen exceeded water quality,.(2) The annual algal density at stratified formation period (April) and stablestratification period (September) reached the highest values were17.63million/L and6928million/L in Shibianyu reservoir, chlorophyll a up to12μg/L ang33.56μg/L. The advantage diatom algae door, and the dominant species of small Cyclotella, Melosira,Fragilaria, and mainly grown in water bodies within the range of2m to5m at stratifiedformation period. The dominant algae cyanobacteria door, and the dominant species ofMicrocystis aeruginosa, mainly grown in the water at the surface to2m at stablestratification.(3) The underlying water body reveal serious anaerobic conditions, and anaerobicarea up to6.7m at stable stratification period (late July to late September). Theanaerobic duration (July21-November3) for up to105days. The bottom waterdissolved oxygen was completely consumed in53days, and oxygen consumption ratewas0.11mg/(m d). The proportion of anaerobic zone reaches up to19.88%at stablestratification. The ratio of the anaerobic zone is reduced to zero at the water bodycompletely mixed periods. The bottom water and surface water are unfit water supply,and it is suitable to take the middle at this periods for water supply.(4) The rate of oxygen reduced at bottom water, inhibiting the release ofnutrients,and inhibiting the growth of algae can be promoted through water mixing. It isrecommend that shibianyu reservoir pumping aerator began to run at the priods of stablestratification (August) in2014. It can destruct water bodies layered formation andinhibition of the growth of algae, and to avoid "blooms" phenomenon.(5) The concentrations microcystin-LR up to148.46ng/L in shibianyu reservoir. Itdid not exceed the national drinking water standard specification (1μg/L). Thedisappearance and highest of Microcystin (MC-LR) have significant lag to the growthpattern of microcystin.