Treatment of septage using lab-scale hybrid constructed wetland system

A lab based hybrid constructed wetland system (۱.۶۴۵ m۲) consisting of sludge drying bed (۰.۱۳۵ m۲), vertical sub-surface flow bed (۰.۵۸ m۲), and horizontal sub-surface flow bed (۰.۹۳ m۲) was operated for the treatment of septage. All the beds were filled with gravels of varied sizes (۵-۴۰ mm), sand (۰.۲۵ mm) and planted with Canna indica L. Average concentration in influent and effluent was observed as; BOD۵ (۲۳۹۵.۶±۱۱۹۶.۴ and ۴۱.۸۷±۸.۹ mg/L), COD (۷۴۴۲± ۷۳۴۲.۶ and ۲۹.۶±۷.۶ mg/L), TSS (۴۹۶۵.۹±۸۰۱.۶۹ and ۳۳۶.۱±۱۵۲.۹ mg/L), TN (۱۷۷۴.۸±۶۹۳.۵ and ۵۵.۷±۱۳.۷ mg/L), and Total P (۸۴۹.۳±۲۳۷.۷ and ۷.۰۵±۳.۵mg/L) during study period. Hybrid System was operated with high influent loads of BOD۵ (۱۷۵.۲± ۸۷.۵ g m-۲ d-۱), COD (۵۴۴.۵±۵۳۷ g m-۲ d-۱), TSS (۳۶۳.۳±۵۸.۶ g m-۲ d-۱), Total N (۱۲۹.۸±۵۰.۷ g m-۲ d-۱), NH۴-N (۷.۸±۱.۱ g m-۲ d-۱), and Total P (۶۲.۱±۱۷.۴ g m-۲ d-۱), throughout the study period. Hybrid-CW has showed significant removal of BOD۵ (۹۹.۱±۰.۳%), COD (۹۹.۷±۰.۳%), TS (۹۸.۲±۶.۸%), TSS (۹۶.۹±۴.۹%), Total N (۹۸.۴±۰.۴ %), NH۴-N (۹۴.۸±۰.۱%), and Total P (۹۹.۶±۰.۱%) from the septage. Finally treated septage met effluent discharge standards for all parameters except BOD۵.

Keywords:

Septage , Hybrid Constructed wetland , Wastewater , BOD , Sludge drying bed