Effect Comparison of Municipal Wastewater in Different Mediums Infiltration System

Abstract:

Two apparatus were established in a pilot laboratory with two different mediums,Apparatus Ⅰ loaded by pure soil,Apparatus Ⅱ loaded by soil and sand in delamination.The removal effects of contamination of two apparatus were compared.During 6 months’ operation,each apparatus was dosed 4 times daily with municipal wastewater at 5 cm·d-1 and 8 times at 10 cm·d-1 and 20 cm·d-1.In 10 cm·d-1,the removal efficiency of Chemical Oxygen Demand(COD),TP,NH4 +-N,TN were 80.7%,38.9%,48.7%,43.5% in Apparatus Ⅰ,respectively,and 88.4%,87.2%,98.2%,24.9% in Apparatus Ⅱ,respectively; in 20 cm·d-1,the removal efficiency of COD,TP,NH4 +-N,TN were 87.1%,56.7%,98.0%,28.9% in Apparatus Ⅱ,respectively; but a jam occurred in Apparatus Ⅰ.The results show that the hydraulic permeability of soil and sand loaded in delamination apparatus is superior to that of Apparatus Ⅰ,and the COD,NH4 +-N removal efficiency of Apparatus Ⅱ is perfect.The hydraulic permeability and antiblockage capability of subsurface wastewater infiltration system improve when mediums are optimized.

Key words:subsurface wastewater infiltration system; municipal wastewater; soil; sand