Guidance Manua pdf

 

ii

 

 

Guidance Manual 

 

for 

 

Reducing 2-Methylisoborneol (MIB) and 

Geosmin in the Metropolitan-Phoenix 

Area Water Supply

  

 

 

 

 

Prepared by 

 

 

Paul Westerhoff 

Department of Civil and Environmental Engineering 

Arizona State University, Tempe, AZ 

 

Milton Sommerfeld 

Department of Plant Biology 

Arizona State University, Tempe, AZ 

 

Larry Baker 

Baker Consulting 

St. Paul, MN 

 

Contributors:  Qiang Hu, Mario Esparza-Soto 

Thomas Dempster and Kirsten Hintze 

Arizona State University, Tempe, AZ

 

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iii

TABLE OF CONTENTS

 

 

Acronyms ..............................................................................................................................iii 

 

Glossary ................................................................................................................................iv 

 

Acknowledgements..............................................................................................................vi 

 

Summary...............................................................................................................................1 

 

Section 1 

 

Introduction................................................................................................................3 

 

Section 2 

 

Background on Taste and Odor Episodes in the Metro-Phoenix  

Region Water Supply System.................................................................................7 

 

Section 3 

 

Multiple Barrier T&O Control...................................................................................15 

 

Section 4 

 

Monitoring and Prediction.......................................................................................18 

 

Section 5 

 

Specific Management Practices ............................................................................30 

 

Section 6 

 

Program Assessment..............................................................................................49 

 

Section 7 

 

Case Studies............................................................................................................54 

 

References............................................................................................................................62 

 

Appendix A ...........................................................................................................................63 

 

Appendix B ...........................................................................................................................67 

 

Appendix C ...........................................................................................................................68 

 

Appendix D ...........................................................................................................................69 

 

 

 

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iv 

 

ACRONYMS  

 

ADEQ – Arizona Department of Environmental Quality 

AF/Day – acre-feet per day 

CAP – Central Arizona Project 

CAWCD – Central Arizona Water Conservation District 

CFS – Cubic feet per second 

COP – City of Phoenix 

DOC – dissolved organic carbon 

DBP – disinfection by-product 

FPA – flavor profile analysis 

GAC – granulated activated carbon 

GC/MS – gas chromatography/mass spectroscopy 

HAA – haloacetic acid 

HPC – high plate counts 

HRT – hydraulic retention time 

M&I – municipal and industrial 

MCL – maximum contaminant limit 

MGD – million gallons per day 

MWD – Metropolitan Water District of Southern California 

MIB – 2-methylisoborneol 

NAWQA - National Water Quality Assessment program (USGS) 

PAC – powdered activated carbon 

SPME – Solid Phase Micro-Extraction 

SRP – Salt River Project  

T&O – taste and odor  

THM – trihalomethane 

TOC – total organic carbon 

USEPA – United States Environmental Protection Agency 

USGS – United States Geological Survey 

UV – ultraviolet 

WSD – Water Services Division (Phoenix) 

WTPs – Water Treatment Plants 

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v 

GLOSSARY 

 

Activated carbon  – carbonaceous material developed by heating various organic 

substrates to very high temperatures in the absence of oxygen.  The result is a material 

with exceptionally high surface area and high adsorption capacity.  In water treatment, 

both granulated activated carbon (GAC) and powdered activated carbon (PAC) are 

used to adsorb soluble organic compounds from water. 

 

Algaecide – a chemical used to kill algae. 

 

Blue-green algae  – primitive algae with a simpler cell structure than more evolutionarily 

advanced algae, characterized by special pigments that sometimes (but not always) 

impart a bluish-green color to the algae.  Some grow attached to substrates (periphyton) 

and others grow suspended in the water column (phytoplankton). 

 

Chelation – weak bonding between an organic molecule and metal ions. 

 

Chlorophyll  – the pigment in plants that imparts the green color and gives the plant an 

ability to carry out photosynthesis. 

 

Chloramines  – compounds formed by reaction of chlorine with ammonia.  Chloramines 

are sometimes used for disinfection in water treatment. 

 

Destratify  – to eliminate layering or stratification, as in the thermal barrier in a stratified 

lake.   Lakes in Arizona normally stratify during the late spring or summer and destratify 

around October or November. 

 

Disinfection by-product  – compounds formed by reaction of chlorine with dissolved 

organic carbon such as trihalomethanes, haloacetic acids, etc. 

 

DOC  – dissolved organic carbon, an aggregate measure of all organic carbon 

compounds dissolved in water.   

 

Epilimnion  – the upper layer of a stratified lake.  During summer stratification, the 

epilimnion water temperature is warmer than the hypolimnion. 

 

Geosmin  - volatile organic compound produced by blue-green algae and certain other 

microbes.  Geosmin is not known to be harmful to  humans, but imparts an unpleasant 

earthy odor and taste to the water at concentrations > 5-10 ng/L. 

 

Haloacetic acids  – a group of compounds characterized by substitution of a halogen to 

replace a hydrogen on the carboxyl group of an acetic acid molecule. 

 

Headspace – space above liquid sample that contains volatile gases. 

 

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