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SOP2 – Challenge Water Modifications
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3.0 SOP 2 - Challenge Water Modifications
Version 2.0
Date of Issuance: July 11, 2012
Author: Janet Barnes, Katherine Ziombra
3.1. Introduction
This section describes the methods to augment ambient water to meet the challenge levels set by
G8 guidelines and ETV protocols for total suspended solids (TSS), particulate and dissolved
carbon (POC and DOC), and biological content (phyto- and zooplankton) when those levels are
requested in a Test Plan.
3.2. Increasing TSS and Carbon Concentrations to Meet Challenge Water Requirements
The liquid mixture created to enhance the ambient water conditions to meet ETV protocols/G8
guidelines is defined as “slurry”. Approximate amounts and specific slurry ingredients were
initially provided by Naval Research Laboratory, Key West based on bench-top experiments.
MERC has refined the method to suit the requirements of the various testing platforms and
ambient water conditions. The exact MERC slurry recipe depends upon the estimated ambient
conditions, the targeted flow rate through the intake pipe, and the targeted tank volumes.
3.2.1. Safety and Precautions
Goggles, gloves and masks are required.
Weigh and/or measure ingredients in a sheltered location.
MSDS sheets are available in the barge office van.
Fresh water is available for washing skin as needed.
3.2.2. Generic Slurry Formula
The following generic calculation is used to estimate the amounts of slurry ingredients required
per uptake trial. (See sections below for details concerning each ingredient.)
Kg material added to liquid in slurry injection tank =
(((enhancement target mg/l/assay factor)*liters ballast)/1,000,000)*1.3333
Enhancement target
= how much material is required to enhance the challenge condition.
Example: If ambient TSS = 15 mg/l and the challenge target = 50 mg/l, the enhancement target
= 35 mg/l.
Assay factor
= ratio of material added to fraction of that material that affects the assay.
1.3333
= ratio of full slurry injection tank to deliverable volume.
Note: the peristaltic positive displacement slurry delivery pump is set for a delivery rate of
liquid slurry l/m = deliverable volume in slurry injection tank (750l) / minutes to fill ballast
tanks + 3-minutes