Installation Instructions
Reverse Osmosis/Deionization Water System
Page 6
Water production
PRODUCT WATER RATE
Usable water production from an RO system is designated
product water rate
, produced on a daily basis. The
rate is normally described in gallons per day (GPD).
REJECT WATER RATE
The flow of water to drain is designated as
reject water
rate
, as measured in milliliters per minute (ml/min).
Using a graduated cylinder the formulas are:
REJECT RATIO
The
reject ratio
is the amount of water produced compared
to the amount of water flowing to drain.
The formula is as follows:
PERCENT RECOVERY
The
percent recovery
is another way to measure the amount
of water produced compared to the amount of water which is
actually used.
The formula to determine percent recovery is as
follows:
NOTE:
Product water rate is the sum of the feed water
flow rate and reject water flow rate.
For example:
Water pressure and temperature
Product water quality and volume of a RO system is
dependent on pressure and temperature. Typically, RO
membranes are tested at standard conditions of 77°F (25°C)
and 60 psi (4 bar) discharging to atmosphere. These factors
should be considered when sizing RO systems for a particular
application. Every degree of temperature below 77 F will
reduce the output of the system by 2%.
Quick connect fittings
Many RO systems utilize Quick Connect fittings. These user-
friendly fittings provide superior performance and may be
provided with this system. Proper use of these push-in fittings
is shown below. Along with these fittings, all tubing selected
must be of high quality and must be cut with a plastic tube
cutter or sharp razor with a clean, square cut.
How to make a connection:
1. Cut the tube square
Cut the tube square. It is essential that the outside diameter
be free from score marks and that burrs and sharp edges
be removed before inserting into fitting. For soft thin walled
tubing we recommend the use of tube inserts.
2. Insert tube
Fitting grips before it seals. Ensure tube is pushed fully into
the tube stop.
Milliliters per minute x 0.38
= gallons per day
Ounces per minute x 11.2
= gallons per day
Product water rate
=10 gpd
Reject water rate
= 40 gpd
Feed water
= (10 gpd + 40 gpd) or 50 gpd
Percent Recovery
= 20%
Reject Ratio =
Reject Rate
Product Rate
Percent Recovery
=
Product H
2
O Rate x 100%
Feed H
2
O Rate
