Water Quality Workshop

EWB South Regional Conference 2013

Greater Austin Chapter

Laura Sampson & Haley Born

Overview Water Quality testing

Case study in Panama

Why Treat Water?

How do we make sure it is Potable? Find out what is in it: So what are some bad things? metals PAHs/organics/pesticides turbidity pH microorganisms virus

Knowing what is in your water will help you to figure out the best removal strategy

Metals

Pesticides, PAH and Other Organics

Nitrate/Nitrite  Human health risk  Blue baby syndrome (methemogobinimea)  EPA 10 mg/L nitrate

 EPA 1 mg/L nitrite

Turbidity  Measured as light scattered at a 90˚ angle  Rough indicator of water quality

Virus Testing

 Not easy to test  No indicator virus,

depends on type of disease  Costly to identify

Microorganisms  Likely most problematic in tropical regions  Bacteria are ~ 1-4 µm  Can be rod, spherical or curly shaped

 Exist as free swimming or biofilms

Not all bacteria are bad but…  Some are pathogenic  Index/indicator organism- a non pathogenic

bacterium that can be cultured to indicate whether fecal contamination is present  Coliforms are bacteria typically thought to exist in

the gut and will thus be found in fecal matter

3 main indicator organisms  Total coliforms  E coli (fecal coliforms)  And Enterococci

Panama Trip – Case Study

Used differential media to investigate the presence of

total coliforms and E. coli in bioactive sand filters

Project History Ojo Norte (Rejected Spring Source)

ALTO

House Where Slow Sand Filter Prototype is Located House Where Travel Teams Stay

Route of Survey

A

Stream Intake for Bajo Non-Potable System Current NonPotable Source for El Centro

C

E

Spring Box for El Centro Potable System

B

Possible Spring Source

E

E Two Cable Crossings

BAJO 0

1. 2. 3.

A Feet

2000

El Centro: 30 houses, church, school, health clinic all connected to dual potable and nonpotable systems. Arriba Bajo: 13 structures (9 sites) – some connected to non-potable Arriba Alto: 12 structures (9 sites) – no current connections

El CENTRO Key Goals for Summer 2012 Trip: A. Install cable crossings and new pipeline B. Debris shield at Bajo non-potable stream intake C. Valve boxes D. Air release valves E. Assessment and health education

Method  Shook sample vigorously in sterile bottles

 Used sterile pipette to transfer some 0.8 mL of

water to testing media  Incubate on human for 2 days to count  Count both blue and red colonies

Sample Collection

 Collect influent and

effluent in separate sterile bottles  Shake sample vigorously in sterile bottles  Label bottles with type and time

Lesson Learned #1 If you use a filter, make sure you know the size of your Bacteria etc.

Testing Media  3M™ Petrifilm™ E. coli/Coliform Count Plates (50)  Free on 3m Website!!!!

http://solutions.3m.com/wps/portal/3M/en_US/Microbi ology/FoodSafety/product-information/educationalresources/university-program/

Plating Samples  Used sterile pipette to

transfer some 0.8 mL of water to testing media  Slowly replaced Plastic

Cover  Avoid Bubbles

Lesson Learned #2

Protect the Babies!!!!!

Incubation

 Incubated at 98.6

degrees  24 hours Total Coliform  48 hours E-coli

MIT Incubators  Chemical incubator pads  Rate of reaction gives 48 hours

of incubation  Put in boiling water to re

crystalize  Field test coming!

Count the Colonies

Results

Tree House Lab of Science!!!

Constituent Test Strips Hach Combination Test Strips (Grainger etc. )  Chlorine  Hardness  Alkalinity  pH  Phosphates  Nitrate/Nitrite  Ammonia

Turbidity

Summary  Potable water is important  Many different types of pollutants  Before treating, you need to know what's in your

water  After treatment, you need to make sure it worked!  Leave time for mistakes if possible

Questions?