The Pilot Study Of The South-to-north Water Transfer Project On Old Networks In Control Of Water Stability In The Typical Urban Area Of Shandong

Taking the water of South-to-North water diversion as the experimental project,under the water supply conditions,iron release process of old pipeline in Jining and Dongying was studied in this paper.The main contents of this research include:(1)the morphology and component of pipeline corrosion scale in Jining and Dongying were analyzed;(2)aimed at the water quality,the chemical stability judgement index of water quality was calculated,the water quality chemical stability was determined;(3)the iron release in pilot pipe network in Jining and Dongying was studied under different water quality conditions;(4)aimed at exceed standard iron release in Jining pilot pipe network after water resource switch,the method to control the excess iron in the effluent in the process of multiple water supply was studied.The main research conclusions are as follows:1? Scanning electron microscope(SEM),Energy disperse spectroscopy(EDS),X-Ray Diffraction(XRD)were applied to analyze pipeline corrosion scale,the main components of corrosion scale in Dongying included Fe3O4(magnetite),?-FeO(OH)(goethite)and CaCO3,the main components of corrosion scale in Jining was ?-FeO(OH)(lepidocrocite).The corrosion scale of the two areas varied depending on water quality and water conditions.2? Langelier saturation index,calcium carbonate precipitation potential(CCPP),Larson Ratio were evaluated,the water was easy to scale,the Langelier saturation index was high,red water was easy to produce when pipe network switched facing with south-to-north water diversion.3?The concentration of iron in pilot pipe network increased with the increasement of the concentration of sulfate and chloride in influent in Jining and Dongying.Through water source switch of south-to-north water diversion,the concentration of total iron in effluent of pipenetwork in Dongying was 0.27 mg/L,the turbidity was 0.87 NTU,meeting the limit of standard for drinking water quality;the concentration of total iron in effluent of pipe network in Jining was 0.45 mg/L,the turbidity was 1.49 NTU,and it could not meet the limit of standard for drinking water quality4? Iron release in pipe network in Jining could be effectively controlled by blending.When Jining groundwater was increased to the ratio 1:1 of Jining groundwater and the water of south-to-north water diversion,the concentration of total iron and turbidity could be up to the standard.The alkalinity of influent was adjusted to 340 mg/L by adding NaHCO3 to pipe network and then the iron release could be controlled.The iron release could be controlled to when the concentration of phosphate reached 2 mg/L by adding Na2HPO3.Residual chlorine was increased to 0.5 mg/L and iron release in pipe network decreased gradually,and iron release would not change with the increasement of residual chlorine,so adding residual chlorine in influent can not make the concentration of total iron and turbidity meet the standard for drinking water quality.