Back to: Table of Contents
SNOWPURE, LLC, 2005-2018
VERSION 3.5 (XL+EXL)
–FEBRUARY 2018
PAGE 61
Appendix #1: Acid Cleaning Procedure / Scale in the Concentrate Stream
Electropure™ EDI has a unique acidic concentrate feature which minimizes the
potential for carbonate scale. However, we still
recommend
that you minimize the
feed hard ions and the total CO
2
+ HCO
3
-
to minimize potential scaling in the EDI
concentrate stream. Note that the injection of acid or antiscalant before the RO will
increase hardness and CO
2
in the RO permeate. These will pass to the downstream
EDI. A pre-RO softener has the additional advantage of removing Iron (Fe) from the
RO feed, which lengthens its life and prevents Iron fouling of the RO and the EDI.
Equipment and Supplies
needed for module service:
Acid-capable pump: 100 lph (0
.
5 gpm) at 2 bar (30 psi)
2 plastic containers 20-50 liter (5-10 gallon), plastic fittings, tubing
Formula
1 (recommended):
This formula is a simple, safe, commercial formula that makes a 2% pH-adjusted
solution of organic acid and chelating agents. This makes a pH solution between 2.5
and 3.5:
►
5 liter
deionized water
►
100 ml
RoClean
TM
L403 solution, from Avista Technologies
9
.
Technical spec sheet and MSDS are available at
www.snowpure.com/knowledgebase.
Formula
2 (next best formula):
This formula is a simple formula using only organic acid. This makes a 5% weak-
acid solution at a pH of about 3:
►
5 liter
deionized water
►
250 gm
citric acid
Formula
3 (only for extreme problems):
This formula makes a 2.5% strong-acid solution, to aid in the removal of extreme
scale levels. This is the most drastic of the three formulas:
►
5 liter
deionized water
►
350 ml
37% Reagent Grade hydrochloric acid (HCl)
10
Safety tip: mixing of acids: remember to add acid to water
—never add water to
acids.
, MSDS and technical sheets available on Avista and SnowPure websites.
10
must be low in iron (Fe)
Chapter 15: Appendices