Fish play a key role aquaponics. They are the first essential living element introduced when starting a new system. Aquaponics, just like any other ecosystem, depends on the nitrogen cycle to convert nitrogen into available nutrients. Ammonia, a bi-product of the respiratory and digestive processes of fish, is the catalyst that starts the “cycling” of our system. As the fish breathe through their gills and excrete waste from their digestive tracts, the ammonia will build up in our aquaponic system. In high concentrations ammonia will kill fish. Thankfully, the presence of ammonia attracts the nitrifying bacteria that we need to cohabit our aquaponics system. The first of which are called nitrosomonas. The nitrosomonas will convert the ammonia in the water into nitrites, which is still toxic to fish. No need to worry though. Good news is that these nitrites will then attract another nitrifying bacteria called nitrospira. The nitrospira is the bacteria we are really after because they are the ones to turn nitrites into nitrates! And plants love nitrates! Nitrates are quickly absorbed by plants, making the excretions from our fish the perfect fertilizer.
In an educational and inspiring podcast on Nick Night’s The Profit Ability Show, Pierre Mainguy describes his journey from being an Los Angeles finance student engaged in venture capitalism to leading an international development NGO, Community First, in Cambodia.
For four years now the Community First had very productive relationship with the University of Edinburgh’s School of Engineering. As part of this collaboration, the students have helped us with sustainable and innovative projects like solar dryers, solar sanitation, and using risk husk for aquaponics, as well as helping us with some engineering and technical drawings. This year we are lucky to welcome a talented and enthusiastic group of young change makers. Here is a little bit about them and their thoughts on the program.
This week in Sen Sok the Community First team came to fix the greenhouse that shelters our first family unit aquaponics system. Due to heavy rains, the original frame and screws bent under the weight of the water. Thanks to our generous donors we were able to purchase an arch welding kit to build a stronger structure to house our system.
It’s always a beautiful day of team building when the weather is 30 degrees Celsius and the humidity being up to 70%. With Pierre off to gather supplies, the rest of the team was able to deconstruct the greenhouse and take down all the broken beams. Next on the list was to weld the new roof pieces together. Our master craftsman, Romain, was able to find his groove and finished fusing all the beams for the roof by the end of the afternoon. It’s never an easy task working out in the villages in the hot sun, but our conversation lifted spirits and our team work kept us moving forward.
Keep an eye out for our post next week as we look forward to finishing up the roof and finally adding fish to our system!
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This week at the Community first Siem Reap Campus we continued to expand our aquaponic production and bio-filtration system with floating raft beds. Taking inspiration from Cambodia's flooded rice fields and other techniques from around the world, these styrofoam boards will suspend all of our salad greens in the nutrient rich water of our aquaponic system. We are excited to get our seeds started so we can transplant them into our system in a few weeks.
We also improved and connected our plumbing to unite our fish tank and grow beds with the new raft system. Our in-house McGyver, Romain Rak , added a connecting pipe topped with a T to distribute the flow of nutrients that flow from the first bed into the second bed, as well as a pipe from the second bed to the IBC tote that holds our fish. Other improvements included installing pipes from our grow beds to the raft bed. Thanks to some smart thinking and zip ties we had all our connections water tight in the first try!
Stay tuned for other developments and aquaponic innovation, as a team of volunteers from the University of Edinburgh come to Sen Sok to help bring aquaponics where most needed.
Every Sunday, at the Community First Siem Reap Campus, we train our future trainers, a group of young, highly motivated ladies who have volunteered to learn about aquaponics under the sole condition that they teach their peers in the countryside. This past Sunday, we built the bell siphon for our first 100% off-grid village system.
This training program is entirely free, and is composed of 10 orphaned young ladies, looking for sustainable solutions to live a better life by farming part of their food in the city while they pursue their respective studies. Some of them live on-campus at Community First and others live together nearby. Our most proficient students are our boarders, as they also help our field team manage current aquaponic systems onsite.
This program is made possible by the ongoing support of the Rotary Clubs of San Marino, Sierra Madre and Pasadena, all located in the District 5300 of Southern California. As such, our team also gathers after the training for an aquaponic lunch and a presentation as a "Friends of Rotary" group. This aspect of the program has since then brought regular guests to our bimonthly events over time.
connecting changemakers and friends of rotary
Every training session, we build a component of the aquaponic systems together. And our last element build is the bell siphon, a popular tool in designing aquaponic systems. This a key component as it is the one that uses simple physics to create a tidal effect in our growbeds, thus making sure the growing media provides both an aerobic and anaerobic environment to enable the bacterial life necessary to the aquaponic cycle to flourish. Checkout this video to see how it works:
There are currently five million undernourished Cambodian citizens. A study released in December 2013 by the Council for Agricultural and Rural Development (CARD), WFP and UNICEF reveals that malnutrition costs between US$250 million and US$400 million annually or 1.5% to 2.5% of Cambodia’s total annual Gross Domestic Product.
WFP Cambodia Deputy Country Director on malnutrition
What is malnutrition and why is it so important to prevent it?
When a person is not getting enough food or not getting the right sort of food, adequate health care and a healthy environment, malnutrition is just around the corner. Malnutrition takes many forms depending on what nutrients are missing in the diet, for how long and at what age. It can even be getting too much food that takes the form of obesity which many people struggle with around the world. Major drivers of poor nutrition are inadequate complementary feeding practices, poor hygiene and high prevalence of diseases, including diarrhea.
However, in Cambodia, the biggest challenge is stunting or chronic malnutrition, which is a growth failure in a child caused by an insufficient intake of essential nutrients in early childhood. During the first 1,000 days of life, between conception and the age of two, children are growing the essential building blocks of their adult life. The best example is the brain. Eighty percent of brain development happens during these critical first two years.
Without the right nutrition during early childhood, a child’s physical and mental development is compromised irreversibly. The body cannot fully develop, cognitive ability is diminished and there is a higher risk for disease and mortality. Not only are these effects irreversible after the age of 2, they are passed on from mother to child, impacting the next generation.
But malnutrition in Cambodia is not just about early childhood. Although they may not be visible to the naked eye, Cambodia has high rates of essential vitamins and mineral deficiencies. WHO ranks micronutrient deficiencies among the top 10 leading causes of death globally.
Malnutrition in Cambodia is a top public health concern and is a cause in approximately one third of child deaths. Cambodia has a staggering 40% of stunted children according to the latest Cambodian Demographic and Health Survey (CDHS 2010). This is the only health indicator that hasn’t improved over recent years and is worse than most countries in the same income group.
We have a lot of exciting aquaponics projects at work here in Cambodia. We have experimental grow beds at the Tuk Vil farm, where we are testing KEM (Khmer Effective Microorganisms) in sustainable aquaponics systems to see how their presence alters the rate of growth of plants. The grow beds are all identical in their set up: they each have a cement pot of about 40 fish underneath, which feeds water in a circuit that flows from the container up to the bed itself where the seeds are planted in gravel.
Gravel is the first growing medium we used as an alternate for soil. Since gravel does not absorb water, it improves the flow of the system while allowing plants to take in more water for themselves. However, it is expensive to buy and transport gravel, making this option less accessible for villagers who typically live on less than one dollar per day. Since our aquaponics systems are meant to act as interventions for this population, other, more accessible and sustainable mediums became necessary to find. Luckily, we have recently had a breakthrough here at Community First in the discovery of a new growing medium that is locally available in abundant quantities and for almost no cost. It also already exists in all the villages that we are working in. This new growing medium is rice husk.
The objective of Community First aquaponics project is to provide individual families without resources the means of farming fish sustainably for their own consumption and for sale on the market. Although we intend to develop solutions applicable in any country, it is important to understand the local environment. Here is what we found during our initial investigation in Cambodia.
Cambodian inland fisheries are among the world’s largest and most diverse, accounting for about 12% of the country GDP. The Tonle Sap provides 400,000 tons of fish per year, valued at about $300M . Today, fish and fisheries are central to the life of the country, just as it was in the ancient Khmer empire.
The lower mekong basin provides the ideal environment for fish to grow at an accelerated rate during the rainy season. Cambodians celebrate the water festival (Bon Om Teuk) during the full moon of October or November, when the flow of Tonle Sap reverses its course to flow north into the great lake. This marks the beginning of the fishing season. The next three months are crucial as people must catch, preserve and store fish for the dry season. Fish is a major part of the Cambodian diet with an average consumption of about 2kg per person per month representing about 6,300 riels per person per month. However the catch fluctuates with the seasons. The catch of the Tonle Sap dai fishery in 2003/2004 was about half of that in 2002/2003, so the price of the most common fish, trey riel, rose more than threefold.
At the beginning of the rain season, when the fish swim upstream into the flooded plain of central Cambodia, they naturally settle in the rice fields. In addition to fish, these fields are home to a large number of other animal species such as crabs, shrimps, clams, snails and insects. Traditional rice farming incorporates fish in their production.