Treatment of septage using lab-scale hybrid constructed wetland system

Abstract

A lab based hybrid constructed wetland system (1.645 m2) consisting of sludge drying bed (0.135 m2), vertical sub-surface flow bed (0.58 m2), and horizontal sub-surface flow bed (0.93 m2) was operated for the treatment of septage. All the beds were filled with gravels of varied sizes (5-40 mm), sand (0.25 mm) and planted with Canna indica L. Average concentration in influent and effluent was observed as; BOD5 (2395.6±1196.4 and 41.87±8.9 mg/L), COD (7442± 7342.6 and 29.6±7.6 mg/L), TSS (4965.9±801.69 and 336.1±152.9 mg/L), TN (1774.8±693.5 and 55.7±13.7 mg/L), and Total P (849.3±237.7 and 7.05±3.5mg/L) during study period. Hybrid System was operated with high influent loads of BOD5 (175.2± 87.5 g m-2 d-1), COD (544.5±537 g m-2 d-1), TSS (363.3±58.6 g m-2 d-1), Total N (129.8±50.7 g m-2 d-1), NH4-N (7.8±1.1 g m-2 d-1), and Total P (62.1±17.4 g m-2 d-1), throughout the study period. Hybrid-CW has showed significant removal of BOD5 (99.1±0.3%), COD (99.7±0.3%), TS (98.2±6.8%), TSS (96.9±4.9%), Total N (98.4±0.4 %), NH4-N (94.8±0.1%), and Total P (99.6±0.1%) from the septage. Finally treated septage met effluent discharge standards for all parameters except BOD5.

Keywords

• septage
• hybrid constructed wetland
• wastewater
• bod
• sludge drying bed