High performance design of trash screens for wastewater treatment

Summary

The reliable operation of the treatment facilities of the municipal wastewater disposal system depends significantly on the efficiency and robustness of the trash screens installed in the head of the process flow at the treatment facilities. In addition trash screens not only protect the equipment from blockages but also prevent suspended solids from polluting natural water bodies receiving effluents. In order to improve the efficiency of trash capture the use of RS screen is recommended. It is highly resistant to mechanical damage caused by large-size impurities in wastewater which results in the reduction of the failure rate and the amount of repair works. The screen design includes a device for additional rake cleaning during the reverse movement to completely eliminate any risk of the rakes being wrapped with filamentary inclusions during the operation. An original mechanism of driving chain tensioning provides for eliminating rake jerking and skewing. The design ensures screen self-sealing in the process of installation into the channel to eliminate unscreened water breakthrough between the frame and channel walls. For the period of RS screens operation the following results were noted: full absence of filter cloth clogging; 3–4 fold screen output increase compared to the previously operated models; reduction of bottom sediments in the channel before the screens; high reliability in case of peak discharge of filamentary inclusions; reduction of energy consumption.

Key words

treatment facilities , wastewater , mechanical treatment , water treatment equipment , trash screen