Thongchai Kanabkaew and Udomphon Puetpaiboon

pp. 749 - 756

Abstract

A pilot scale aquatic pond, with dimensions of 1.8 m in length, 0.6 m in width and 1.2 m in depth, was
constructed at the Hat Yai Municipality Central Wastewater Treatment Plant, Thailand. The experiment was
carried out to investigate the enhanced removal efficiency of unconventional plants for aquatic treatment
system as post treatment. Wastewater from the selected pond of the Hat Yai Municipality Central Wastewater
Treatment Plant was introduced to the systems using peristaltic pumps to maintain a fixed flow rate at HRT
of 5.4 and 10.5 days, respectively. Lotus (Nelumbo nucifera) and hydrilla (Hydrilla verticillata) were planted
along with one control unit. Influent and effluent were analyzed for pH, SS, BOD₅, TKN, NH₃-N, NO₂^--N,
NO₃^--N, TP and Coliform bacteria twice a week. The results showed that ponds with aquatic plants were
superior to those without plants. The system with lotus showed the best removal efficiency for wastewater
treatment. For the system with hydrilla, it was found that pH and SS of the effluent were high. It might not be
suitable to use hydrilla for effluent polishing. This study could emphasize that lotus and hydrilla could
provide an alternative aquatic plant system for wastewater treatment.