DUBAI // Like many keen gardeners, Dan Frawley only has to travel as far as his own back yard if he wants some fresh tomatoes, aubergines or chilis.
The difference is, he doesn’t have to do any digging. Mr Frawley, an Australian engineer, has set up a special aquaponics system that uses fish waste as fertiliser for the vegetables.
He first set it up two years ago in his ground-floor flat in The Greens, and since he moved to a larger villa in Umm Suqeim his operation has tripled.
“I wanted to move the system but the tricky thing is, if you start a new system, you put water in and you’re essentially starting from zero again, because all the water is conditioned and it’s going through the process of nitrification, which is turning ammonia into nitrogen,” he said.
Mr Frawley moved the water and conditioned soil before setting up the larger system, which now has three growing beds and 1,000 litres of water for the fish.
“Since 2013, I did a lot more research and learnt about the region,” he said. “I talked to experts because they’re a great source of knowledge for me.
“One guy gave me helpful tips on how to create a natural biorhythmic environment, so if you want more microbe growth you put things like sugar into the system. And if you want carbon, you put in flour. So common things we think about putting in our body are good for the fish, plants and water.”
Mr Frawley initially bought his fish from a commercial farm but has since visited the Ministry of Environment and Water’s Sheikh Khalifa bin Zayed Al Nahyan Centre for Marine Research in Umm Al Quwain.
“They’ve got an initiative to restock the waterways with hammour, tilapia and other types of fish local to the region,” he said.
“They were amazing and very helpful. They gave me all the fish I needed free, about 30 tilapia, and lots of information, and they said to send anybody to them as they give the fish away to farmers or anyone wishing to contribute.”
But because of the summer heat, not all of the fish survived.
“I harvested them all and took them out of the water to the Umm Suqeim fishing harbour where they were filleted and we’ve been eating them for the past few weeks,” Mr Frawley said.
“I was also able to grow hundreds of tomatoes from five different varieties, thanks to heirloom seeds from Australia. We got so much that we ended up making sauces with them.” Crops such as mint, chili and lemongrass have also done well.
“Aquaponics is a good idea,” said Hoda Jaffal, an agricultural engineer at Al Yousuf Agricultural and Landscaping in Dubai.
“It’s a water-saving system because it’s being recycled and it’s also organic, so there is no need to add fertiliser, which is very important. The plants will feed on the fish waste and it’s also faster for the growth of the plant than traditional methods.”
Ms Jaffal said the system was useful to people with small areas of land. “You can make it in a room in your backyard if you don’t have a lot of space. It grows fish and plants at the same time,” she said.
“It’s more efficient than other systems and you don’t have to apply pesticides or chemicals. So at the end of the day, it’s a healthy product.”
But Ms Jaffal said an aquaponics system could be costly.
“Vaporisation is a bit high here so maybe the water consumption can be high even if it’s being recycled,” she said. “But it’s still better than growing with regular methods.”
cmalek@thenational.ae
