Vikanda Thongnuekhang and Udomphon Puetpaiboon

pp. 521 - 528

Abstract

Most of the concentrated latex factories in the South of Thailand discharge treated wastewater that
contains high level of nitrogen to a nearby river or canals leading to a water pollution problem. A study of
land treatment system was conducted to treat and utilize nitrogen in treated wastewater from the concentrated latex factory. The experimental pilot-scale land treatment system was constructed at the Faculty
of Engineering, Prince of Songkla University, Hat Yai Campus. It consisted of water convolvulus (Ipomea
aquatica, I. Reptans), tropical carpet grass (Axonopus compresus (Swartz) Beav.) and control unit (no plantation). The treated wastewater from the stabilization pond system of the selected concentrated latex factory
in Songkhla was used to irrigate each experimental unit. Influent and effluent from the experimental units
were analyzed for TKN, NH₃-N, Org-N, NO₃^--N, NO₂^--N, BOD₅, sulfate, pH and EC. The land treatment
system resulted a high removal efficiency for nitrogen. Tropical carpet grass provided higher removal
efficiency than other units for all parameters. The removal efficiency of water convolvulus and control unit
were not significantly different. The average removal efficiency of TKN, NH₃^-N, Org-N, BOD₅ and sulfate
for tropical carpet grass unit were 92, 97, 61, 88 and 52%, for water convolvulus unit were 75, 80, 43, 41 and 30%, and for control unit were 74, 80, 41, 31 and 28%, respectively. Mass balance of nitrogen transformation
was conducted. It revealed that plant uptake was the major mechanism for nitrogen removal in land treatment.