1. Elizabeth Coler
University of California Santa Cruz

2. 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.

3. 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?

4. Materials and Methods
Study Sites
 Los Pinos (LP)

5.  Monteverde Country Lodge (MCL)

6.  Bajo Del Tigre (BDT)

7.  Monteverde Institute (MVI)

8. Data Collection and Analysis
 Samples collected once a day at each site, before
and after treatment
 Tests conducted in lab
 YSI- pH
Specific Conductivity
Conductivity
Total Dissolved Solid
Salinity
Temperature
Dissolved Oxygen
 Test Kit- Nitrate Nitrogen
 Statistical analysis
 Paired T-tests for before and after
 Kruskal Wallis to compare after samples

9. Results
0
1
2
3
4
5
6
7
8
9
LP MCL BDT MVI
AveragepH Before Treatment
After Treatmenta a
b
c
• Average pH values of samples.
KW=14.33, df=3, p<0.002

10. 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 products
Residue left from greywater

11. 0
0.2
0.4
0.6
0.8
LP MCL BDT MVI
S.Conductivity
(mS/cm^c)
a
a
a
b
0
0.2
0.4
0.6
0.8
LP MCL BDT MVI
Conductivity
(mS/cm)
a
a
a
b
0
0.1
0.2
0.3
0.4
0.5
LP MCL BDT MVI
TotalDissolved
Solids(g/L)
a
a
a
0
0.1
0.2
0.3
0.4
LP MCL BDT MVI
Salinity(ppt)
• Average values of S. Conductivity, Conductivity,
Total Dissolved Solids, and Salinity.
b
a
a
a
b

12. Discussion
 LP and MVI higher levels
after > before
 MVI water becomes
stagnant in last pipe
 LP water build up at end
biogarden/ leaf litter

13. 19.5
20
20.5
21
21.5
22
22.5
23
23.5
LP MCL BDT MVI
Temperature(*C)
a
b
c
a
0
2
4
6
8
10
12
LP MCL BDT MVI
DissolvedOxygen(mg/L)
a
a
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

14. 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

15. 0
0.2
0.4
0.6
0.8
1
1.2
LP MCl BDT MVI
NitrateNitrogen(mg/L)
a
b
a
a
• Average values of Nitrate Nitrogen levels
KW=12.92, df=3, p-value=0.0048

16. 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

17. 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

18. Acknowledgements
 Sofia
 Emilia
 Danielle
 Jorge
 Rafael (Los Pinos)
 Monteverde Institute
 Monteverde Country Lodge
 Bob (Bajo Del Tigre)