Water System Design Manual
December 2009
Page 287
Project Report
Treated water design criteria (total dissolved solids (TDS) goal)
Corrosive nature of RO permeate
Raw water quality, including temperature
Treated water quality (from pilot plant study or analogous system)
Intake design, including provisions to discourage clogging by mussels (for example,
alternating intakes or over sizing intake pipe)
Membrane type (cellulose acetate, polyamide/composite)
Membrane configuration (tubular, spiral wound, hollow fine fiber)
Membrane characteristics (TDS range)
Pretreatment requirements (for example, turbidity reduction, Fe/Mn removal, anti-scale
stabilization, microbial control, chlorine removal, dissolved solids reduction, pH
adjustment, hardness reduction); two treatment trains minimum
Useful life of membrane/expected membrane replacement schedule
Expected recovery rate (percent)
Corrosion control
Other post treatment requirements: degasification for CO
2
/H
2
S removal; disinfection -
4-log viral disinfection meeting the requirements of WAC 246-290-451 must be
provided
Treatment unit sizing (peak day demand with multiple units for reliability)
Description of instrumentation/controls, including alarms and telemetry for remote
operation, and provisions for protecting instrumentation and electrical components
from corrosion
Pump sizing (including manufacturer's performance curves)
Equalizing storage for efficient operation of high pressure pumps
Waste disposal (must be acceptable to the Department of Ecology)
Spill containment for generator fuel if applicable (110 percent of fuel storage tank
volume)
Noise abatement
Testing and certification procedures for startup