Elizabeth Coler

University of California Santa Cruz

Introduction Greywater is the wastewater from the kitchen,

laundry, bathroom sinks, and showers. Fats and oils

Food particles

Soaps

Chemicals

Solvents

On average in Costa Rica 187 L of water consumed per person each day.

Approximately only 3.6% of greywater is treated.

Questions

How does the quality of greywater compare before and after treatment?

How do the results of this treatment differ between the diverse systems at various locations?

Materials and Methods Study Sites

Los Pinos (LP)

Monteverde Country Lodge (MCL)

Bajo Del Tigre (BDT)

Monteverde Institute (MVI)

Data Collection and Analysis

Samples collected once a day at each site, before and after treatment

Tests conducted in lab YSI- pH

Specific ConductivityConductivityTotal Dissolved SolidSalinityTemperatureDissolved Oxygen

Test Kit- Nitrate Nitrogen

Statistical analysis Paired T-tests for before and after Kruskal Wallis to compare after samples

Results

0

1

2

3

4

5

6

7

8

9

LP MCL BDT MVI

Ave

rag

e p

HBefore Treatment

After Treatmenta a

b

c

• Average pH values of samples.

KW=14.33, df=3, p<0.002

Discussion Most pH values within

expected range: 6.5-8.4 (Morel and Diener 2006)

MVI before sample more acidic: 5.40

Coffee

Tea

Acidic food particles

Rice

Meats

Dairy productsResidue left from greywater

0

0.2

0.4

0.6

0.8

LP MCL BDT MVI

S.

Co

nd

uct

ivit

y (m

S/c

m^

c)

aa

a

b

0

0.2

0.4

0.6

0.8

LP MCL BDT MVI

Co

nd

uct

ivit

y (m

S/c

m)

aa

a

b

0

0.1

0.2

0.3

0.4

0.5

LP MCL BDT MVI

To

tal

Dis

solv

ed

S

oli

ds

(g/L

)

aa

a

0

0.1

0.2

0.3

0.4

LP MCL BDT MVI

Sa

lin

ity

(pp

t)

• Average values of S. Conductivity, Conductivity, Total Dissolved Solids, and Salinity.

b

aa

a

b

Discussion LP and MVI higher levels

after > before

MVI water becomes stagnant in last pipe

LP water build up at end biogarden/ leaf litter

19.5

20

20.5

21

21.5

22

22.5

23

23.5

LP MCL BDT MVI

Te

mp

era

ture

(*C

) a

b

c

a

0

2

4

6

8

10

12

LP MCL BDT MVID

isso

lve

d O

xyg

en

(m

g/L

)

aa

b

a

• Average values for Temperature and Dissolved Oxygen

KW=9.21, df=3, p-value=0.03 KW=9.25, df=3, p-value=0.026

Discussion BDT before sample low level

of DO

Consumption > Production due to fly larvae in tank

Greater temperature (EPA 2012)

BDT after sample high level of DO

Lowest temperature

Fly Larvae in BDT tank

0

0.2

0.4

0.6

0.8

1

1.2

LP MCl BDT MVI

Nit

rate

Nit

rog

en

(m

g/L

)

a

b

a

a

• Average values of Nitrate Nitrogen levelsKW=12.92, df=3, p-value=0.0048

Discussion

MCL after sample higher in Nitrate Nitrogen

Combination of greywater and black water

Black water 90% more Nitrogen than greywater (Abedin and Rakib 2013)

MCL sampleOther

Why is this Important?

Greywater is a large environmental issue

Any untreated grey water runoff into streets and streams

Pollutes the surrounding habitats

Harmful to all living organisms

Lead to disease outbreaks

Treated greywater can be reused for gardens or toilets

Acknowledgements Sofia

Emilia

Danielle

Jorge

Rafael (Los Pinos)

Monteverde Institute

Monteverde Country Lodge

Bob (Bajo Del Tigre)