The Research On Water Pollution Analysis And Safeguard Of Perch Water Tanks In Shenzhen’s Multi-storey Residences

As people’s living standard enhancing continuously, the problem of drinkingwater quality is attracting more and more attention of people. Head water tank hasbeen widely used as a water supply facility from the1980s.But now,because of thesecondary pollution problem and so on, it is questioned by the public.How to dealwith the head water tank’s secondary pollution economically and reasonably is aproblem to be solved urgently.This research uses33residential quarters’ water tanks as example,studies on theevaluation and transformation model of head water tanks and project measures aftertransforming the water tank.Firstly, this thesis investigates each residential quarter’s head water tanks,analyses and summarizes the reason for the tank’s water quality pollution, proposesthe corresponding measures for solution and discusses the problem of cancelling thewater tank.In order to confirm the sequence of cancel and transformation for the head watertank, this study uses33residential quarters’ water tanks as example and establishesthe evaluation and transformation model of head water tanks.It assesses eachresidential quarter’s tanks in terms of water pressure、service population、liningmaterial、 water supply mode、 volume、 water quality and pressure’s effectivecomplaint、pipeline corrosion degree and facilities’ fault number,then establishes themodel;This model collects original data through the expert’s opinionaires，then usesAHP and MATLAB software to determine the weight of every factor;It concludes thescore of each item through WATERGIS、EPANET software、water supply networkmodel of Shenzhen and other data.At last,this reaserch works out each residentialquarter’s total score rank of head water tanks.The rank controls whether or not tocancel the water tank,and also provides a basis for cancel and transformation of thehead water tank in Shenzhen.In order to offset the insufficient of hydraulic pressure when the tank has beencanceled, this research makes techno-economic comparison on all kinds of hydraulicpressure remedy measures,and then confirms the best pressurization measures foreach residential quarter.This research uses CFD software to simulate flow condition in the head water tank,for tanks which are not canceled provisionally.In order to solve the problems ofrecirculation zone、short flow zone and wake space in the tank, this research uses themethods of setting the guide plate、changing the corner circular、setting two inletpipes and adding perforated plate to transform the water tank.So the flow condition isimproved to plug flow and the secondary pollution is reduced to the minimum.