1. PERSPECTIVES AND OPPORTUNITIES TO CLOSE THE SANITATION LOOP IN R URAL CAMBODIA
Potential solutions to integrate public health and agriculture through lime
Brian Chhor & Katie Nelson
Stanford Gap for Good, XSEED
September 2012
3. BACKGROUND
PROJECT BACKGROUND
Based on last summer's research,
tying agricultural value to human
waste could provide incentive to
change sanitation practices.
4. BACKGROUND
SUMMER OBJECTIVES
Explore opportunities to close the sanitation loop in
rural Cambodia:
» Exploring existing sanitation systems worldwide
» Developing an understanding of the Cambodian context
» Testing concepts in the field
5. METHODOLOGY
INITIAL EXPLORATION OF
SANITATION
TREATMENT OPTIONS:
CHEMICAL
Alkaline
Ultraviolet
Chlorine
STEP 1: Research
BIOLOGICAL
Biodigestion
Vermiculture
Composting
Aerobic
Anaerobic
PHYSICAL
Pasteurization
Shearing
Filter
11. TECHNICALFEASIBILITY
Types of Lime
CaCO3
(Limestone)
• Easiest and safest to
handle
• Replenishes calcium in
soils
• Used in toothpaste,
cereal, antacids
• When burned
(calcination), produces
CaO
CaO
(Quicklime)
• Will spontaneously react
with CO2 and H2O in air,
can ignite combustible
materials
• Can reach temp of
100 C
• Dries and pasteurizes
sludge, raises pH
• Causes severe burns
when inhaled or placed
in contact with moist skin
or eyes.
Ca(OH)2
(Hydrated Lime)
•Relatively stable compared
to CaO
•Does not generate heat,
raises pH to 12
•Good for building and
mortar- aggregate and
stabilizer
•Good for white washing,
pickling, and deodorizing
animal waste
•Unprotected exposure to
Ca(OH)2 should be limited.
It can cause severe skin
irritation, chemical burns,
blindness, or lung damage.
12. TECHNICALFEASIBILITY
Types of Lime
CaCO3
(Limestone)
• Easiest and safest to
handle
• Replenishes calcium in
soils
• Used in toothpaste,
cereal, antacids
• When burned
(calcination), produces
CaO
CaO
(Quicklime)
• Will spontaneously react
with CO2 and H2O in air,
can ignite combustible
materials
• Can reach temp of
100 C
• Dries and pasteurizes
sludge, raises pH
• Causes severe burns
when inhaled or placed
in contact with moist skin
or eyes.
Ca(OH)2
(Hydrated Lime)
•Relatively stable compared
to CaO
•Does not generate heat,
raises pH to 12
•Good for building and
mortar- aggregate and
stabilizer
•Good for white washing,
pickling, and deodorizing
animal waste
•Unprotected exposure to
Ca(OH)2 should be limited.
It can cause severe skin
irritation, chemical burns,
blindness, or lung damage.
13. TECHNICALFEASIBILITY
Lime in Sanitation
» High pH levels destroy and prevent regrowth of pathogens
» Vector attraction barrier prevents insect infection of waste
» Reduce heavy metal content
» Destruction of odors
14. TECHNICALFEASIBILITY
» Increased pH improves acidic soil
» Classified as a “soil amendment,” not a fertilizer
Improves soil quality over time rather than having a direct impact
on short-term crop growth
» Decreased insect and pest attraction
» Increases soil permeability and water percolation
» Improves conditions for nitrogen-fixing bacteria
» Captures phosphates and ammonia
Lime in Agriculture
21. TECHNICALFEASIBILITY
KEY POINTS:
» Chemically, lime is well adapted for both:
Sanitation purposes : kills pathogens, insect attraction barrier, odor
reduction
Agricultural purposes: increased pH and soil permeability, phosphate and
ammonia fixing, pest reduction
» Calcium hydroxide (Ca(OH)2) is the most promising form
Safer than CaO and more alkaline than CaCO3
» Lime needs to be adequately mixed with waste to ensure
sterilization
23. OPERATIONALVIABILITY
iDE’s Current Use of Lime
» Sold through FBA network
5-10% of overall sales
Sales have doubled in past year
Sold mainly to NGOs
» Focused on vegetable plots
» Pilot test:
Recommendation was 300-500 kg/hectare.
In pilot test (1 HH), used 300 kg on 1 hectare.
Rice yield increased from 1 ton/hectare to 3.5 ton/hectare
27. OPERATIONALVIABILITY
iDE’s LIME SUPPLY CHAIN
?
FBAs use the lime
themselves and sell
to famers in small
quantities
Lors Thmey
NGOs
Don Bosco
CADF
iDE partners
AVIL
USAID
29. OPERATIONALVIABILITY
Household costs & Alternate sourcing
Amount of Ca(OH)2 to get pH 11.5:
1 teaspoon lime/ gal waste
(0.528 teaspoon/ 2L flush)
Amount of Ca(OH)2 per household per year:
-5 people per household
-one flush per person per day
-Density Ca(OH)2 = 2.211 g/cm3
23.1511 lb per household
per year
Cost of Ca(OH)2 to household:
-US $90-200 / Metric Ton (via Lianyungang Jialei
International Trade Co., Ltd)
-Avg. $145 / metric ton ($0.0658 /lb)
-Ca(OH)2 from Thailand and Kampot (2008)
-$110-120 / metric ton ($0.0521 /lb)
-Ca(OH)2 from Battambang
-$90 / metric ton ($0.0408 /lb)
$0.94 per household per
year
30. OPERATIONALVIABILITY
KEY POINTS:
» iDE currently uses lime and has a full supply
chain already built around it
» Supply chain should be reexamined for
inefficiencies and quality control
» Most customers are repeat buyers
» The cost per household of a lime
distribution scheme should cost less than
$3/HH/year
32. CONSUMERDESIRABILITY
Central question:
Is alkaline stabilization of waste viable in the
Cambodian context?
» Relevant information about existing agricultural practices and
preferences
» Understanding of waste management and sanitation norms
» Acceptability of central design concept
37. FARMING
INSIGHT:
While the FBAs need to use the product
themselves and observe the proof of its
efficacy, farmers are willing to listen to FBAs
recommendations based on their reputation
alone.
38. CONSUMERDESIRABILITY
FARMING
INSIGHT:
FBAs are the thought leaders of the farming
community, and advocate high inputs for high
yields. Those farmers that ascribe to this
philosophy are passionate about farming; those
who do not are not willing to expend the effort
or money to make improvements.
48. CONSUMERDESIRABILITY
WASTE: Pol Pot
“It was like being forced to drink from a water hose until
you overflowed and couldn’t take anymore. There is no
room left for anything else. We are full, fed up.”
51. CONSUMERDESIRABILITY
WASTE
INSIGHT:
In trying to make full use of livestock, waste is
seen as a consumable and valuable good.
Humans, on the other hand, do not have the
same association --so it is hard for people to
see human excrement as anything more than
unwanted waste.
53. CONSUMERDESIRABILITY
WASTE: Rice vs. Vegetables
INSIGHT:
The difference in technique and use between
rice and vegetables ‘shields’ farmers and
consumers from the negative associations of
human waste.
57. IMPLEMENTATIONPLAN
KEY POINTS:
Opportunities:
» FBAs as resource within village network
» Prevalence of lime usage
» Desire for "better" organic fertilizer
» Fear of bacteria
Challenges:
» Wariness of chemical additives
» Stigma associated with human waste
» Lack of motivation to change farming practices
61. BUSINESSINSIGHTS
GENERAL INSIGHTS
» General excitement
Odor elimination
Yield increase
Bacteria sterilization
» Concerns about safety
» Concerns about adherence
» Reception varied depending on
price point
62. BUSINESSINSIGHTS
» Could be integrated into daily chores.
» Adherence is a concern for children, who already don’t
practice sanitary behaviors.
» People need to know that the product is safe to handle and
apply.
HOUSEHOLD INSIGHTS
64. BUSINESSINSIGHTS
» Some farmers associate hiring external help
with a loss of control over their farming practices
(and outcomes).
» Even at an affordable price point, people
considered the idea of hiring labor to be a luxury,
and perhaps needlessly extravagant.
» Hiring someone to empty a latrine is less
desirable than hiring someone to transport and
apply waste to crops.
SERVICE INSIGHTS
65. BUSINESSINSIGHTS
» Several people we spoke to mentioned that
human waste is currently commoditized in other
countries, so there is precedent for establishing a
Cambodian market.
» Fertilizer sourced from Thailand and Vietnam
already contains human waste; consider a similar
integration with fertilizer production in Cambodia.
COMMODITIZATION INSIGHTS & PRINCIPLES
66. BUSINESSMODELS
» People recognized the potential for mass
production under this system, but were wary of using
it themselves.
» Mass production of public waste would require
secondary processing to break connection between
waste and fertilizer product.
SCALING INSIGHTS & PRINCIPLES
67. BUSINESSESMODELS
KEY POINTS:
Opportunities:
» Excitement about cheaper, organic fertilizer
Especially FBA buy-in
» Potential for scale-up
Existing public waste streams
Analogous market
Challenges:
» Adherence
» Safety & toxicity
» Waste stigma
68. Technical Feasibility
» Appropriate
sanitation use, due to
pathogen & odor
reduction
» Appropriate for
agricultural use, due
to positive effects of
pH increase on soil
» Lime-sludge mix
requires
homogenization and
2 hours of treatment
to sterilize
» Importance of
containment of
potentially harmful
substance
Operational Viability
» Existing supply chain,
customer base, sales
support
» Need to explore novel
sourcing options to ensure
quality control, optimize
cost savings
» Potential for low cost
treatment solution
Consumer Desirability
» Willingness to adopt
new practices,
especially cheap,
organic solutions- need
for procedural
transparency
» Stigma against human
waste use on HH
consumption crops
» Importance of
transformationBusiness Models
» Potential for scale-up
» Need for additional
processing to increase
acceptability
» Concerns about safety,
adherence in HH model
KEY MESSAGES:
74. IMPLEMENTATIONPLAN
Research question & study scope
Determine Sample size
Recruit FBAs as target users
Create small-scale latrines and demo plots
•Both rice and vegetables
Bacterial testing
Pilot Test
User feedback
75. ACKNOWLEDGEMENTS
Team EZPZ
John Thomas
Peter Mulligan
Stanford XSEED and
d.School
My Le
Joan Dorsey
Rita Lonhart
Marlo Dreissigacker
iDE Cambodia
Yi Wei
Pisith Lim
Philip Charlesworth
Lida Seng
Special thanks to:
Elyse Marr
THANKS TO:
Genesisof the project: Stanford D. School’s EXTREMEEZPZSummer 2011 researchBased on past research by iDE and our team, we were informed that people in Cambodia, living on an extremely low wage, did not prioritize sanitation compared to other needs. They were aware of the benefits of sanitation but were not willing to spend their sparse income on it. Based on existing research, it seemed to make the most sense to base any concept on a dual function-- something that improved public health but provided an added agricultural benefit.
Our team had sought additional fundraising to pilot the EZPZ, and the feedback that they received was that urine diversion tackled only a part of the problem, and that they needed to develop a more holistic waste management approach. We were brought on at this stage to try to help the team tackle this problem. We decided to approach the problem by trying to ground the problem and potential solutions in existing examples of waste management globally, and, of course, the needs, resources, and values of the Cambodian people.
limestone- readily available to be quarried. 10% of all sedimentary rocks. can be mixed with other minerals. (with magnesium is dolomitic). good for replenishing calcium in soil. easiest to handle. bones, shells, toothpaste, cereal, antacids.used to make ca0 when burned (calcination). cao-quicklime, the most volatile of the three. heated to release co2 and cao. when reacting with water, can release 1,140 kJ/kg CaO In a homogeneous mixture, the quicklime reacts with the moisture present in the sludge. This exothermic reaction generates significant amounts of heat energy which will dry the sludge (temperatures can reach in excess of 100ºC) as well as chemically binding 32% of it’s own weight of water as hydroxide. If the correct quicklime dose is applied, the temperature will be easily maintained at over 55ºC for 75 minutes(1), this dries and pasteurises the sludge. can also spontaneously react with co2 in air to form caco3 again. intense glow- limelight. main source of ph coems from conversion to another productcaoh- after water is added, cao turns into caoh. relativeluy stable compared to cao. can riase ph to 12. does not generate heat. hydroxide ions great for increasing pH. can also put calcium back into soil. makes calcium carbonate when contact with co2. used for building stuff becuase good aggregate and sabilizer, good for white washing, pickling, deodorizing animal wastequicklime: Because of vigorous reaction of quicklime with water, quicklime causes severe irritation when inhaled or placed in contact with moist skin or eyes. Inhalation may cause coughing, sneezing, labored breathing. It may then evolve into burns with perforation of the nasal septum, abdominal pain, nausea and vomiting. Although quicklime is not considered a fire hazard, its reaction with water can release enough heat to ignite combustible materials.caOH: Unprotected exposure to Ca(OH)2 can pose health risks, so should be limited. It can cause severe skin irritation, chemical burns, blindness, or lung damage.Calcium hydroxide is intended to be an ascetic inorganic substance, and like many chemicals, it reacts badly with organic tissue. calcium hydroxide will burn or irritate the skin, and if it reaches sensitive areas, such as the eyes, ears and throat, loss of vision and severe pain can result. Vomiting, internal bleeding and abdominal pain are common symptoms of poisoning. If inhaled, calcium hydroxide can make breathing difficult. Dissemination of the chemical from the lungs to the blood can lower blood pressure and change the acidity of the blood.
limestone- readily available to be quarried. 10% of all sedimentary rocks. can be mixed with other minerals. (with magnesium is dolomitic). good for replenishing calcium in soil. easiest to handle. bones, shells, toothpaste, cereal, antacids.used to make ca0 when burned (calcination). cao-quicklime, the most volatile of the three. heated to release co2 and cao. when reacting with water, can release 1,140 kJ/kg CaO In a homogeneous mixture, the quicklime reacts with the moisture present in the sludge. This exothermic reaction generates significant amounts of heat energy which will dry the sludge (temperatures can reach in excess of 100ºC) as well as chemically binding 32% of it’s own weight of water as hydroxide. If the correct quicklime dose is applied, the temperature will be easily maintained at over 55ºC for 75 minutes(1), this dries and pasteurises the sludge. can also spontaneously react with co2 in air to form caco3 again. intense glow- limelight. main source of ph coems from conversion to another productcaoh- after water is added, cao turns into caoh. relativeluy stable compared to cao. can riase ph to 12. does not generate heat. hydroxide ions great for increasing pH. can also put calcium back into soil. makes calcium carbonate when contact with co2. used for building stuff becuase good aggregate and sabilizer, good for white washing, pickling, deodorizing animal wastequicklime: Because of vigorous reaction of quicklime with water, quicklime causes severe irritation when inhaled or placed in contact with moist skin or eyes. Inhalation may cause coughing, sneezing, labored breathing. It may then evolve into burns with perforation of the nasal septum, abdominal pain, nausea and vomiting. Although quicklime is not considered a fire hazard, its reaction with water can release enough heat to ignite combustible materials.caOH: Unprotected exposure to Ca(OH)2 can pose health risks, so should be limited. It can cause severe skin irritation, chemical burns, blindness, or lung damage.Calcium hydroxide is intended to be an ascetic inorganic substance, and like many chemicals, it reacts badly with organic tissue. calcium hydroxide will burn or irritate the skin, and if it reaches sensitive areas, such as the eyes, ears and throat, loss of vision and severe pain can result. Vomiting, internal bleeding and abdominal pain are common symptoms of poisoning. If inhaled, calcium hydroxide can make breathing difficult. Dissemination of the chemical from the lungs to the blood can lower blood pressure and change the acidity of the blood.
Table from: http://cee.eng.usf.edu/peacecorps/5%20-%20Resources/Theses/Sanitation/2008Mehl.pdfCalcium hydroxide (hydrated lime) is an alkaline compound that can create pH levels as high as 12.4.At pH levels greater than 12 and increased temperatures, cell membranes of harmful pathogens are destroyed. Because lime has low solubility in water, lime molecules persist in biosolids to prevent regrowth of pathogens. The high pH also provides a vector attraction barrier, preventing flies and other insects from infecting treated biological waste. The high pH also will precipitate most metals present in the waste and reduce their solubility and mobility. The solubility of calcium hydroxide provides free calcium ions, which react and form complexes with odorous sulfur species such as hydrogen sulfide and organic mercaptans. As a result of this reaction, the biological waste odors are actually destroyed, not just “covered over.”The US EPA defines two types of biosolids with respect to pathogen reduction: Class A (no detectable pathogens) and Class B (a reduced level of pathogens). Both classes are largely considered safe, but additional requirements are necessary for a sludge to meet Class A requirements, such as municipal wastewater treatment.Alkaline stabilization can achieve the minimum requirements for both Class A and Class B biosolids with respect to pathogens, depending on the amount of alkaline material added and other processes employed. Generally, alkaline stabilization meets the Class B requirements when the pH of the mixture of wastewater solids and alkaline material is at 12 or above for 2 hours of contact. Class A requirements can be achieved when the pH of the mixture is maintained at or above 12 for at least 72 hours, with a temperature of 52°C maintained for at least 12 hours during this time.
The addition of alkaline stabilized biosolids results in more favorable conditions for vegetative growth by improving soil properties such as pH, texture, and water holding capacity. Alkaline stabilized biosolids provide pH adjustment, nutrients, and organic matter, reducing reliance on other fertilizers. Alkaline stabilized biosolids are also useful as daily landfill cover. In most cases, lime stabilized biosolids are blended with other soil to achieve the proper consistency for daily cover. It is marketed as a soil amendment, rather than a fertilizer, because it improves the quality of the soil itself over time, rather than having a direct impact on crop growth in the short term. killls pests and bacteria by denaturing them. prevents vector attraction so fewer insects and such.binds to clay soils to make them more permeable, more percolation, and water holding capacity. good for replenishing ca ionsmakes soil better for nitrogen fixing bacteriacaptures phosphates and ammonia
Conclusion: needs to be well mixed
NEWSLIDEWITHTAKEHOME
We were excited to discover upon arriving here that iDE is already using lime for agricultural purposes. It is sold through the FBA network for $8 a 30kg bag, and according to Chanta, comprises 5-10% of overall FBA sales. (largest single sale $600) However, iDE does not engage in particularly intensive marketing for lime- most customers are already aware of the product before they buy it. iDE has performed several demonstrations with lime on test plots, and currently recommends its use primarily for vegetable plots rather than rice fields, due to the quantity required to make a significant difference to the soil pH.
The existing supply chain is problematic for a couple of reasons. Most importantly is that it is not clear what product, exactly, these farmers are being sold. Several reported that when they used too much lime, their crops 'melted'. Another showed us the lime that he had just applied to his field-- it was a large white pebble. There seems to be a great deal of inconsistency in the product being sold by iDE-- and this raises serious concerns about both the safety and the efficacy of the product. Additionally, sourcing lime from the markets of Vietnam is both inefficient, by not seeking the procut at the source transport costs are undoubtedly higher, and unstable-- relying on the market not to change the price or stop selling the product would be very problematic if we began to sell this product as a necessary sanitation product.
We met with an engineer who had been involved in an ADB rural development project to stabilize Cambodian roads using lime. Lime is available from Vietnam, Thailand, and Cambodia, albeit in small quantities. The industry in Thailand and Vietnam is considerably more developed than in Cambodia, so Cambodian production is limited to 20-30 tonnes per week from Kampot and Battambang. While this quantity was insufficient for their road stabilization project, this quantity would be more than sufficient for agricultural and sanitation uses in Cambodia, and could provide cost-savings in transportation. [for further information, contact Collin Sinclair at collin.sinclair1802@gmail.com]
FarmingFrameworks for UnderstandingFecal Matters
For some of the people we spoke to, farming was a livelihood. For others, it was a means of supplementing another income stream. For some people, it was a passion. “If [farmers] are passionate about what they do, they will try new things. If you love what you do, you will do all you can to make it better.” When we asked people where they had learned to farm, most answered that they had grown up farming. We observed that people's attitude towards farming itself influenced the way that they went about it. Most of the FBAs, arguably the most passionate farmers, were devoted to their crops and could describe in detail their techniques and travails.
There seems to be a general trend in SvaiRieng towards younger people giving up (or devoting less time/money) to farming in order to earn money more easily at day jobs. This is in direct conflict to the FBAs’ dictum that more inputs (of time, money, expertise) are required to obtain higher yields.
A willingness to try to learn new things was associated with success in this context. One FBA said that when he initially heard about lime, he decided to test it himself. He prepared his vegetable plot for planting, applying lime to half and leaving half bare. Then he planted his crops and observed the difference in growth. When he saw that the half that had lime applied was better, he was convinced about the efficacy of the product, and was able to recommend the products to his customers.
FBAs take their position as advisors seriously. While the FBAs themselves need to use the product themselves and observe the proof of its efficacy, farmers are willing to listen to FBAs recommendations based on their reputation alone.
When other farmers were asked who they would go to advice for new techniques, many of them responded by naming the FBA. The FBAs would go around looking for farmers to share knowledge with and have consultations or lessons over tea. Those farmers who seemed most willing to listen to his advice and learn his techniques, were in turn generally the most successful farmers in a community, many of whom passed on their knowledge to other people.
Because FBAs are the early adopters of any new farming technique in a community, they are in a unique position to provide traction for our product. Because of this trickle-down information effect, it makes sense to target any product at the FBA. If he likes it and recommends it, no other infrastructure or marketing will be necessary.
On the other hand, not all changes in farming technique are seen as improvements.One of the farmers we spoke to said that people in his village bought vegetables from him because they were concerned about the produce they were getting from the market. A rumor had spread that people who sold in the market were putting a chemical after they picked their cucumbers that made them swell up and appear larger. He said that in order to assuage his customers’ fears, this farmer made sure that his wife picked the cucumbers in front of the customers, so that they could be sure they were not adulterated. “People put chemicals in everything now”, he complained. “Fish food, pork, even lemongrass.” “People put more chemicals in things, and their lives are shorter because of it.” There is increasing concern about chemical additives in food, and being able to see the process being done seems to be one way of assuaging these concerns.
This concern about the increase in chemical additives parallels some of the older farmers concerns about mechanization. The increased reliance on machines to do things like peel rice signifies to these farmers a disconnect between people and their farming. This opinion, espoused by older farmers, was a further condemnation of the kind of ‘shortcuts’ like overreliance on chemicals that cut down on work at the expense of the quality of the product.
A lot of farmers were asked why chemical fertilizer worked, and none of them were able to answer. All of them wished that they knew how.
So we were hearing all of these negative things about chemicals, but most people seemed to use them on their crops. One farmer’s metaphor for the use of fertilizer was MSG. A little bit is good, he said. A lot doesn’t make much of a difference, and in fact, can be harmful, in the case of fertilizer. One young female farmer who did not seem especially familiar with farming technique said that she used too much fertilizer, and her rice was not good.
Most FBAs agreed that using too much fertilizer makes the ground hard and requires crop rotation. It also made the rice red, which they saw as unnatural. However, they recognized the beneficial outcome of the chemical fertilizer on increasing their yields.
Most farmers contrasted chemical fertilizer with organics animal waste. Everyone we spoke to that kept animals used the waste on their crops, and all were very satisfied with it. It made the rice full and white, and the soil loose, unlike chemicals. Most people agreed that it makes the best fertilizer, but most don't have enough of it to cover all of their crops and so supplement with chemical fertilizer.
The general conclusion, then, was that farmers are caught between the knowledge that chemical fertilizer is bad for their crops in the long term, with the fact that it increases the quality of their yields.
We can conclude, then, that any potential product needs to emphasize the transparency of the fertilizer production and growing process. A lack of understanding about the way that chemicals work could contribute to the suspicion about them, so we need to make sure that a general understanding of the way that lime works is conveyed. Finally, emphasizing the fact that people are producing this fertilizer themselves, and therefore know exactly what they’re using, could promote trust in the product and its efficacy. On the other hand, human waste can be polarizing, as we learned when we asked about it.
Three different people mentioned that people were forced to use human waste as fertilizer under the Khmer Rouge, but the emotional reaction was varied. One man said that because people were forced to suffer so much and work so hard then, they would be unwilling to do so again. One man said that only old people and babies would eat shit– people that are young and strong would not stand for it. So there seems, in some ways, to be a sense of pride that prevents people from using waste. However, the two other people seemed matter-of-fact about this historical association and remarked that they had seen how well human waste worked as fertilizer and would be willing to try to use it. Thus, we are asked to reevaluate again: How much yield or benefit is necessary to justify the amount of work put in? We see the same clash in how people define success. Here, the sentiment expressed correlates success with less. For our “passionate” farmers, success was defined in part as a desire for improvement and a willingness to try new things.
Even beyond the historical associations with human waste, we had some very visceral reactions to its use. Most people claimed not to use it; some were horrified at the thought. Many cited “disgust” as the main reason against using human waste to grow food – particularly other peoples’ shit. One farmer said that he used his latrine's contents on his rice fields, but would not use anyone else's. "Our waste does not smell as bad", he said. Later, he added that he would never buy anyone else's shit to use on his field, either.
On the other hand, we had already established that people considered animal waste to be the best fertilizer. So there is something about inherent about human waste that makes it somehow less acceptable than animal waste.
It seemed as though a part of the answer may be that animals are, in their entirety, a consumable good. If you’re going to kill it and eat it for food, it also makes sense to use its other byproducts. Because there is no commoditization associated with humans, this is not the case. There also seems to be some intangible associated with excrement- because it’s my waste (or worse, someone else’s) I don’t want to eat it.
People did not think that animal waste could spread the kind of bacteria that would get people sick. In fact, some people felt that a single family’s waste shared bacterial content and was therefore more acceptable than an outsider’s waste.
As much as people seemed concerned about bacterial contamination from using human waste on their crops, we were interested to learn that this distinction only extended so far. The same farmer who indignantly demanded why we would ask him to consume his own waste, when asked how he emptied his latrine, responded that he emptied it onto his rice field. People were horrified at the idea of using waste on vegetable plots, but almost all of them emptied their latrine onto their rice fields. The reason for this differentiation may have to do with proximity to home, the lack of processing (FBA mentioned vegetables you ‘eat immediately’ like cucumbers) or the fact that rice is, for most of these people, a cash crop that they sell rather than consuming themselves. In general, people used different products and techniques on their vegetables and their rice. Some also did not consider the income from the crops fungible-- one man used his rice profit for ceremonies, and his vegetable profits for his daily use. One woman used her rice profit to invest back in her farming, and her vegetable profit for daily use. The emphasis on vegetables for daily use may be because the rice crop is a less certain proposition in years with poor rainfall, as seems to occur often in SVR.
Those who had biodigesters usually mixed the contents of the latrine into the biodigester along with animal waste, but they clearly did not consider this 'human waste'. The importance of this transformative process, the biodigester, was underscored when a farmer we spoke to said that people would buy human waste as fertilizer, but only if they didn't know what it was.
In this model, the FBA is trained by iDE in lime safety and practice, and then he sells lime and a dispenser, along with instruction in how to use it. We emphasized that lime was a toxic substance, and that the dispenser was important to keep the powder away from contact with skin and eyes. We also made sure to underscore that this system required people to add lime EVERY SINGLE TIME they used the toilet.
In this model, we made sure to emphasize that people would hire an expert to come and perform the sterilization process for them. He would come every time their latrine filled up, mix in the lime, empty the latrine, and then transport the fertilizer to their fields. We made sure to emphasize the difference between the two models-- that in the first one, you did everything by yourself, and that in the second, you hired someone to do it for you.
One person said that “if people had this, everyone would buy a latrine”
One woman mentioned that this seemed like something the women could do while the men were off in the fields and at work.
The concept of hiring someone to empty the latrine for them was met with mixed responses. The FBAs, in particular, seemed reluctant to relinquish control of some aspect of their farming practices. Misunderstanding the model (and that it meant that the entrepreneur would return yearly to repeat the emptying) many of them said that they would hire him once, to learn the technique so that they would be able to do it themselves. The FBAs were generally the most well-off of the people we spoke to, and they mostly agreed that they would prefer to do the process themselves, for the control of the process and for the flexibility of being able to do it whenever they wanted. People who were poorer generally thought that hiring someone was needlessly extravagant. One female FBA indicated that hiring, when necessary (like for additional farm labor) was only done within a village-- because of the high cost of transportation, people rarely hired outsiders, so there seems to be no precedent for this kind of system. What got people excited was the idea of someone putting the waste on the crops for them, potentially more so than they were about having him scoop the waste and treat it for them. This was especially notable when the farmer asked about how much they would charge for far away fields. We had not anticipated this question, so we responded that each km away would cost $1. They exclaimed that this was a very good price. With the high price of gasoline, it could be that they were simply excited to have cheaper labor (and maybe equipment) than they could provide themselves. This means several things: one, We need to think more carefully about the resources and labor required for this job (and find comparisons) to set a more accurate price point. More importantly, when it is more economical or convenient to do so, people are perfectly willing to hire someone. Hiring in general, then, has more to do with the perceived cost of labor than anything else. Additionally, this indicates that transportation is a burning issue for people and either needs to be highlighted as a key feature of an entrepreneurial model, or, if not viable, removed from model and re-tested
One farmer mentioned that people buy and sell human waste in Vietnam. Human waste in fertilizer is secret
FBAs and farmers understood the entrepreneurial potential of this system, and considered whether it would be possible to produce this product on a wider scale by sourcing waste from schools and pagodas, but noted that it would be better not to tell people that it was made of waste. Would sell it, but not use it on his own crops.Better not to tell people what it is? Secondary processing to remove stigma, or implications for scale. Either mass-produce so that it becomes more of a manufactured good, or people have to know its their own.
