aite, 1984; Miller, 1995; Andrew & Jakson, 1996).
The Mae Moh power plant is a thermal electricity unit,
operated by Electricity Generating Authority of Thailand
(EGAT). It consists of 13 power generating units, which can
be operated continually to produce about 2,625 megawatts
at full capacity. All the power generating units use lignite
coal fuel to heat water in boilers producing hot steam for
operating the generators. The drained water and wastewater
activities of the power plant are treated by both physical and
biological processes after being released into the main
treatment system. The goal of this research was to determine
and compare the water quality and concentrations of some
heavy metals (As, Pb & Zn) in two water supply reservoirs
for the power plant, four ponds in wastewater treatment
system and a reservoir, which is the final drainage recipient
from the wastewater treatment system of the Mae Moh
power plant.