Download Report

Anthroponic System Proposal
By Henrique Sánchez, 04/03/2015
1. The Definition
Anthroponics can be defined as a recirculating soilless agriculture system that uses
natural bacterial cycles and other organisms to convert human biowaste into plant
fertilizer. It will typically combine aspects of aquaponic farming, organic hydroponics
and wastewater treatment.
An Anthroponic system can be supported on only human urine, human feces and
(theoretically) on both combined. For this proposal, we aim to build a human urine
system.
2. The Fundamentals
There is very little research done on the topic of anthroponic systems. The only
academic document so far is the master thesis Aquaponics and its potential
aquaculture wastewater treatment and human urine treatment, Sánchez, 2014. There,
the detailed construction of an anthroponic system using human urine is described,
however no information on ratios between human urine used, filtration, water volume,
and growing space are presented.
Knowledge on this subject could be improved by performing simple experiments and
testing a main assumption as the control system and variations on this system for
relevant parameters.
Aleece Landis is a known member of the Backyard Aquaponics community, and she
was one of the first people performing regular testing and documentating an
anthroponic system (known as “peeponics”). In her system, she used a Barrel-ponics®
design and used urine using a similar methodology described by the above master
thesis. Since her system was substaintially smaller than the one described in the
master thesis, it would seem interesting to explore and test her descriptions, sizes and
ratios and use them as the main values to be confirmed. Her system specifications are
specified below in Table 1, as well as the calculated values per liter of biofilter volume.
Table 1: Aleece Landis’ Anthroponic System as documented in Backyard Aquaponics and
calculated values per liter of biofilter media volume.
Landis’ System
Calculated
Values
2
Aged Urine
(mL/day)
Biofilter Media
Volume (L)
Total System
Water Volume (L)
Growing Area (m )
200
250
283 - 378
0,67
0,8
1
1,13
-
3. The Objective
One of the objectives of the experiment are to figure out the average and median time
that it takes urine to reach a pH of 9 and therefore be regarded as safe to use in the
anthroponic system. The other objective is to find if Aleece Landis’ ratio of volume of
aged urine per day per biofilter media volume can be confirmed, and what can happen
to the system’s readings (EC, pH, NH3/NH4+, NO2, NO3) if the daily dosing of urine is
changed.
If we can calculate these unknowns, we can then issue guidelines with enough
confidence on how to properly design a human urine supported anthroponic system as
well as design better and bigger systems for ourselves that will allow us to test the
same ratios in a different scale.
4. The Experiment
While preparing the main experiment, three 100mL jars will be collected with fresh
urine at the same time from the same individual. The urine will come from a healthy
individual, under no type of medication, and will be collected after the first 2 seconds of
urination, to prevent any solids build up to be collected from the first 2 seconds of
urination. The jars will be kept sealed and outside of direct sunlight. After 1 week since
collection, one of the jars will be opened and tested for pH. A second jar will be opened
and tested for pH after 2 weeks, and the last jar will be opened and tested for pH after
3 weeks. A control pH test of fresh urine will also be performed.
The main experiment will be to build three flood and drain systems on a timer using
Landis’ ratio and cheap accesible materials that Hemmaodlat is already comfortable
with using. A system will normally consist of two boxes: one the main water reservoir
where the aged urine is added, the second will be the biofilter and growing box. Each
system should require a water pump, plumbing components, growing media, and a
light source to operate. The boxes used will be the standard black IKEA SAMLA boxes,
with a size of 39cm x 28cm x 28cm. All grow boxes will be filled with same age seeds
of Romaine Lettuce (Lactuca sativa L. var. longifolia).
The first system (System 1) will operate under Landis’ values and will serve as the
control system with 4 plants. The second system (System 2) will have half as much
urine dosing (7,8 mL/day). The third system (System 3) will have double the urine
dosing as the first system (31,2 mL/day). Below follows a table with the ratios used in
each of the system:
Table 2: Experiment parameters for each system
System 1
(control)
System 2
System 3
Aged Urine
(mL/day)
Biofilter
Media
Volume (L)
Total System
Water
Volume (L)
Growing
2
Area (m )
Number of
plants in
grow box
15,6
19,5
22
0,11
4
7,8
31,2
19,5
19,5
22
22
0,11
0,11
4
4
Below a figure of the three systems is presented:
Figure 1: AutoCAD representation of all three systems
All systems will be filled with Gold Label Hydrocorn, a growing medium commonly used
in Hemmaodlat. This type of light expanded clay aggregate has a specific surface area
(SSA) of 1250 m2/m3 (as reported by Albuquerque et al, 2009). Considering the
volume of biofilter in use (19,5 L = 0,0195 m3), this amounts to a biological surface area
(BSA) of 24,37 m2. Using Bright Agrotech’s information on BSA, it is claimed that a
system must have at minimum 2,5 ft2/gallon of water, with a recommended ratio of 10
ft2/gallon of water. According to these ratios, and converting our systems’ values to the
Standard System (24,37 m2 = 262,3 ft2 and 22 L = 5,8 gallons), our systems have a
BSA of 45 ft2/gallon of water, which is far above the minimum and recommended
values, and should guarantee more than adequate biofiltration. However, a more
common SSA value for light expanded clay aggregate is of 250-300 m2/m3 (as
resported by FAO, 2014). According to this SSA, we get a BSA of 0,0195 x 250 =
4,875 m2 (or 52,47 ft2). Thus, the system has a BSA of 52,47/5,8 = 9,06 ft2 per gallon of
water, which is still inside Bright Agrotech’s target range.
After the systems are set-up and cycled, the systems can be evaluated on a qualitative
basis (crop production, general crop health) or in a quantitative basis (EC, pH,
NH3/NH4+, NO2, NO3) so that a conclusion can be drawn. It is possible that Landis’ ratio
is wrong, but one of the two other systems performed better. It is also possible that all
three systems perform equally as bad, or that all perform equally as well. In either
case, quantitative testing (EC, pH, NH3/NH4+, NO2, NO3) will be useful in determining
the specific issues with each system in regards to each other.
4. The Costs
The costs are expressed as if all materials must be purchased and there is no
possibility of re-using existing materials at Hemmaodlat. Prices are from IKEA and
Hydrogarden.se.
Product
SAMLA box (39x28x28)
Hailea HX 1500 or HX
2500 (must pump 60cm
height)
Gold Label Hydrocorn 45L
Plumbing components
(pipes, tubings, fittings)
Net Pots Nätkorg 2’’
ROOT!T® 50st refill påse
seedling medium
Light Fixtures
Amount
7
3
Price (kr)
175
357 - 537
2
-
399
Up to 500
12 (4 per grow box)
1
24
149
3
?
Total estimated price is calculated to be around 1784kr in the worst case scenario, not
counting the light fixtures.