Sediment-Containing Sewage Separation Using Intermittent-Discharge Columnar Hydrocyclones

Yuekan Zhang,Peikun Liu,Meng Yang

doi:10.3390/w12102883

Abstract

Traditional hydrocyclones can be used for the concentration of sewage-containing sediments, but the low underflow concentration and the high content of fine particles result in a large subsequent dehydration workload. This study aimed to investigate the effect of columnar hydrocyclone column height on separation performance and the change in the internal flow field after the underflow orifice of the hydrocyclone was closed, so as to provide a theoretical basis for improving the ability to treat the sewage of the hydrocyclone. Numerical simulation was used to examine the change in the separation performance of the hydrocyclone and the effect of column height on the separation performance of the hydrocyclone in the case of the closed underflow orifice during intermittent discharging. The results indicate that a proper increase in column height was beneficial to improve the separation performance of the hydrocyclone. With the increase in the closing time of the underflow orifice, the particle content at the bottom of the hydrocyclone increased significantly. The experiment proves the feasibility of the intermittent discharge method in practice, and this working method can effectively increase the underflow concentration.

Highlights

Sewage contains a large number of fine particles
This study proposed an intermittent-discharge columnar hydrocyclone
As the in the hydrocyclone increased, which was beneficial for improving the separation effect. It can column height increased, the space that participated in the separation and the residence time be seen that the pressure values at different cross-section positions decreased with the increase in the of particles in the hydrocyclone increased, which washydrocyclone

Summary

Introduction

Sewage contains a large number of fine particles. If the sewage goes directly to the urban sewer without treatment, it causes problems, such as pipe blockage and serious pipe wear. The gravity sedimentation method is often used to treat sediment-containing sewage; it has the shortcomings of large site area, low sedimentation efficiency, high investment cost, and so forth. Hydrocyclones are often used for mineral separation and slurry concentration, and they can be used in the treatment of sewage containing sediments. A hydrocyclone is a device [1,2,3,4] for the efficient separation of two-phase mixtures, using the principle of centrifugal sedimentation. It has the advantages of a simple structure, convenient operation, strong separation ability, and a small site area. Hydrocyclones play an increasingly important role in the pretreatment of sewage wastewater and surface sewage [5,6,7,8,9]

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Conclusion