With the project phase behind us we’re looking back at the lessons learned, as well as looking ahead at how to add further economic value to waste recycling through agriculture.
Safi Sana recycles organic waste by converting it into energy and nutrient-rich compost. The compost is then used as substrate for seedling production in our greenhouse. Nutrient-enriched substrate has a higher value than compost, adding further value to one of Safi Sana’s key end products. The project with Via Water has been crucial in helping us to construct a greenhouse, commence initial sales of seedlings and train growers to optimise their use of compost.
Using compost as substrate, however, has come with its own challenges. Sound composting practices allow for good hygiene, but the liquid waste contains high levels of sodium (Na). We had to mix the compost with local coco peat at a ratio of 1:9 to create the optimum concentration for quick and reliable rooting and plant growth. This ratio was calculated through a number of nursery trials.
The same can be said for the effluent water, as the nutrients in it include a high dosage of sodium, making the water un-useable for recycling hydroponics. This water can, though, be very useful for open field agriculture and short cycle cultivation. We therefore decided to install an ebb-flow system for short cycle cultivation of seedlings (and herbs) are developing a system for large scale open field irrigation using slow sand filtration for hygiene followed by drip irrigation. Year-round monitoring of the nutrient parameters in both the effluent water and compost will make it possible to calculate seasonal supplement nutrient dosage. In a follow-up project, funded by the Vitol Foundation, we are combining the same type of year-round monitoring with field trials for irrigation.
As for the greenhouse, being located in Ghana brings its own challenges. In Greater Accra and the delta area where Safi Sana is located, the climate is especially hot and humid. The greenhouse therefore needed as much ventilation as possible while keeping insects out. A greenhouse with a fine-netted wall system, an overarching roof and a large netted roof-cavity was selected for this location. However, the greenhouse would still heat up too much during the day, hitting almost 50 °C just before noon. After installing an internal shade net the average temperature remained the same, but the peaks (and troughs) in temperature were less extreme, enabling us to maintain an acceptable year-round cultivation climate. Currently the Fresh Green Ghana project evaluates our greenhouse along with a number of others in Greater Accra in order to continue improving the design of greenhouses for Ghana.
Business-wise the greenhouse has a great deal of potential. The simple ebb/flow irrigation system allows for reliable, highly competitive produce. The small scale of our greenhouse works for us, allowing our ‘green-fingered’ personnel to work on other agri-activities. The greenhouse’s greatest challenge remains the sales: seedlings are a relatively new concept to Ghana, and as growers don’t properly calculate the cost of their own in-house seedling production, they are not willing to pay a reasonable price for them. It will take a few more seasons to convince them that professionally-grown seedlings (that root better, are more uniform and are grown from higher-quality seed material) can actually boost profit. Developing the market, therefore, has turned out to be the most difficult challenge to tackle in this project.