Entries by Bob Spon

IL AWWA Best Paper Award

The Thurston E. Larson Best Paper Award was presented to Robert Spon for his presentation of “Do you Really Have a Free Chlorine Residual?” at the 2005 Annual Meeting of the Illinois Section American Water Works Association held in Springfield, IL March 14, 2006. For a copy of the full article contact Spon Water Consulting

Phosphate Treatment FAQs – Part 1

What is phosphate treatment? Phosphates are water treatment chemicals (dry or liquid solutions) used to correct problems resulting from inorganic groundwater contaminants (iron, manganese, calcium, etc.) and also to maintain water quality (inhibit corrosion, scale, biofilm, reduce lead and copper levels) in the distribution system. Orthophosphate and polyphosphate are two general types used in water […]

Phosphate Treatment FAQs – Part 2

How are phosphate dosages controlled? Since phosphates do not change basic water chemistry, measuring phosphate residuals in the raw and finished water is necessary to monitor the dosage rate. Orthophosphate ion (PO4) is the most common species used to measure the initial and total quantity of phosphate in the water. Orthophosphate can be measured on […]

NSF Std. 60 Listed Orthophosphate Chemicals

Approximate % active as PO4 Approximate pH value (1% solution) Name: Phosphoric Acid Formula: H3PO4 % active: 75% (pH 1) Name: Monosodium orthophosphate Formula: NaH2PO4 % active: 79% (pH 4.5) Name: Monopotassium orthophosphate Formula: KH2PO4 % active: 70% (pH 4.5) Name: Disodium orthophosphate Formula: Na2HPO4 % active: 67% (pH 9.1) Name: Dipotassium orthophosphate Formula: K2HPO4 […]

NSF Std. 60 Listed Polyphosphate Chemicals

Approximate % active as PO4 Approximate pH value (1% solution) Name: Sodium acid pyrophosphate Formula: Na2H2P2O7 % active: 86% (pH 4) Name: Tetrasodium pyrophosphate Formula: Na4P2O7 % active: 72% (pH 10.5) Name: Tetrapotassium pyrophosphate Formula: K4P2O7 % active: 58% (pH 10.5) Name: Sodium tripolyphosphate Formula: Na5P3O10 % active: 77% (pH 9.5) Name: Potassium tripolyphosphate Formula: […]

Manganese (Mn) Fraction Analysis

1. Total Mn: Analyze raw water or system water samples for total Manganese. 2. Soluble Mn: Analyze water samples using the PAN Method, but delete the use of the ascorbic acid reagent (reducing agent) in the Hach Step #6 to identify the initial soluble Mn. This portion of Mn (soluble/unbound) can be sequestered (tied-up) by […]

Iron (Fe) Fraction Analysis

1. Total Fe: Analyze raw or finished water sample using Ferrover #8008 for total Iron. 2. Soluble Fe: Analyze raw or finished water sample using the 1,10 Phenanthroline Method #8146 to determine soluble iron. Soluble unbound (ferrous) iron can be sequestered with polyphosphate to prevent water discoloration, or to minimize iron color when corrosion occurs […]

Phantom Free Chlorine Residuals

A growing number of water systems have naturally occurring ammonia (NH3-N) and organic contaminants (TOC) in their water supplies. These contaminants react with chlorine treatment to form combined chlorine residuals (chloramines, chlororganics), if insufficient chlorine is applied to reach breakpoint free chlorine residuals. In this case, when testing the water for free chlorine residual, the […]