Effectiveness of Wastewater Treatment Plants in Reducing Pathogens in the

Paso del Norte Region

Geoffrey B. Smith

New Mexico State University, Las Cruces, NM

Kevin H. Oshima

Environmental Protection Agency, Cincinnati,OH

Project Objectives

• Based on high incidence of pathogen occurrence in Rio Grande and irrigation canals (eg., Morales et al. 2006), effectiveness of local wastewater treatment plants was questioned.

• Recently developed methods (Morales et al. 2003) allow for quantification of protozoa, bacteria and virus.

Paso del Norte Study Location

Methods

One liter sampled from Influent, Ten liters of Effluent sampled.

Protozoa.Giardia and Cryptosporidium quantified by EPA Method 1623,

with a Immunomagnetic Separation (IMS) purification step.

Bacteria. Helicobacter pylori. Quantified by selective medium containing 5 antibiotics and 2 antifungal agents (Morales and Vidal).Fecal coliforms by Standard Method 9222 D.

Virus. E. coli phage and Pseudomonas phage by EPA method 1602.

Influent Protozoa El Paso del Norte

0

1000

2000

3000

4000

5000

LasCruces,NM ElPaso,TX Juarez,MX

Pro

tozo

a / L

Crypto

Giardia

Cryptosporidium - El Paso del Norte Sewage Pathogens as Epidemiology Assay

0

500

1000

1500

2000

2500

Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Feb-04

Infl

ue

nt

Cry

pto

spo

rid

ium

/ L

LasCruces,NM

ElPaso,TX

Juarez,MX

Sewage Pathogens as Indicators of Current Disease? Cryptosporidium

0

200

400

600

800

1000

0 2 4 6 8 10 12

Months (after December 2004)

Infl

ue

nt

Cry

pto

sp

ori

diu

m /

L

Las Cruces,NM

El Paso,TX

Juarez,MX

Cryptosporidium Occurrence is Correlated between Las Cruces, NM and El Paso,TX

R2 = 0.9119

0

1000

2000

3000

4000

0 500 1000 1500 2000 2500

Las Cruces Cryptosporidium

El

Pa

so

Cry

pto

sp

ori

diu

m

Cryptosporidium Occurrence is Correlated between El Paso,TX and Juarez, MX

R2 = 0.7958

0

400

800

1200

1600

2000

0 1000 2000 3000 4000

El Paso Cryptosporidium

Jua

rez

Cry

pto

sp

ori

diu

m

No Relationship between Fecal Coliforms and Coliphage Virus in Wastewater

LC fecal vs E.coli phage (Effluent)

y = 0.0003x + 81.928R2 = 8E-06

0

200

400

600

800

1000

1200

1400

0.00 5000.00 10000.00 15000.00

Fecal coliform

E.c

oli

ph

ag

e

Series1

Linear (Series1)

LC fecal vs E.coli phage (Influent)

y = 0.0845x + 2.9119R2 = 0.0008

0

1

2

3

4

5

6

8 8.2 8.4 8.6 8.8 9 9.2 9.4

log10 of fecal coliform

log

10

of

E.c

olip

ha

ge

Series1

Linear (Series1)

Log Reductions:How well does a treatment plant reduce the levels of pathogens?

Eg. Influent Effluent Log Reduction Plant A 10,000 10 log(10,000/10) = 3

(one-thousand-fold lower) Eliminated 99.9% of influent

Plant B 10,000 1000 log(10,000/1000) = 1 (ten-fold lower) Eliminated only 90% of influent

Protozoa Log Reductions – El Paso, TX

Log Reduction Values for Crypto. and Giardia from El Paso

R2 = 0.1322R2 = 0.02

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

37987 38078 Jul.-04 Oct.-04

Jan.-05

Apr.-05

Jul.-05 Oct.05 Jan.06

Month-year sampled

Log

Red

uct

ion

EP Crypto.EP GiardiaLinear (EP Crypto.)Linear (EP Giardia)Linear (EP Crypto.)Linear (EP Crypto.)

Protozoa Log Reductions - LasCruces,NM

R2 = 0.041

R2 = 0.3689

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1/1 1/6 1/11 1/16 1/21 1/26 1/31 2/5

Log

Red

ucti

on

LC.Crypto

LC.Giardia

Linear(LC.Crypto)Linear(LC.Giardia)

R2 = 0.0021

R2 = 0.0226

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Feb-04

J. Crypto

J. Giardia

Linear (J.Crypto)Linear (J.Giardia)

Protozoa Log Reduction - Juarez, MX

Fecal Coliform – Log Reductions

-2

0

2

4

6

8

10

12

Jun-03 Jan-04 Aug-04 Feb-05 Sep-05 Mar-06 Oct-06

Fec

al c

oli

log

Red

uct

ion

LasCruces,NMElPaso,TXJuarez,MXLinear (Juarez,MX)Linear (ElPaso,TX)Linear (LasCruces,NM)

Conclusions

• Las Cruces, NM and El Paso, TX wastewater treatment plants functioned properly over the 2-year study.

• The Ciudad Juarez Planta Norte functioned in reducing putative Helicobacter pylori, but had little or no effect on fecal coliforms, and coliphages. On average, protozoa were reduced by 1 log (90% reduction).

Giardia - El Paso del Norte.

0

2000

4000

6000

8000

10000

Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Feb-04

Influ

ent

Gia

rdia

/ L

LasCruces,NMElPaso.TXJuarez,MXLinear (LasCruces,NM)Linear (ElPaso.TX)Linear (Juarez,MX)

Giardia (Influent)Similar trends in Las Cruces and El Paso

0

1000

2000

3000

4000

5000

6000

Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Jan-04 Feb-04

Influ

ent G

iard

ia /

L

LasCruces,NMElPaso.TXLinear (LasCruces,NM)Linear (ElPaso.TX)