8 Biofilter Aquaponic System for Nutrients …
123
According to Goddek (2017), there are several designs available for aquaponic
system. The designs are based on hydroponic systems, except that the water source
for the aquaponic system comes from the fish tank and is eventually returned to its
source of origin. There are three types of aquaponic systems, namely media filled
systems, nutrient film technique (NFT) and floating raft system. In media filled
system, the hydroponic component is distinguished first if it employs a media or
not. According to Estim et al. (2018), the system removed 59% PO 4 −N and 50%
NH 3 −N. Boxman et al. (2018) reported that Sesuvium portulacastrum (flower plant)
was able to remove 59% N from marine fish wastewater.
The second system is the nutrient film technique (NFT). This system consists of
the plant roots being exposed to a thin layer of nutrient water that runs through most
often a PVC pipe. Based on previous studies by Buzby and Lin (2014) and Endut
et al. (2010), these types of aquaponics needs a large area to build this system. In
Buzby and Lin (2014), the system was able to remove 81% of NH 3 −N by using
lettuce and 89% by nasturtium. Meanwhile, Endut et al. (2010) claimed that the
system removed total ammonia nitrogen (TAN) and total nitrogen (TP) by 86.22%
and 49.74%, respectively. The shallow flow of water only reaches the bottom of
the thick layer of roots that develops in the trough while the top of the root mass
is exposed to the air, thereby receiving an adequate oxygen supply. Channel slope,
length and flow rate must all be calculated to make sure the plants receive sufficient
water, oxygen and nutrients. If properly constructed, NFT can sustain very high plant
densities. In aquaponic NFT systems, the biofilter becomes crucial as there is no large
surface area whereby bacteria communities can develop.
The floating raft system is another type which has great potential for commercial
use in aquaponics (Wongkiew et al. 2017; Wang et al. 2016; Lam et al. 2015). The
system plants are grown on floating styrofoam rafts. The rafts have small holes cut
in them where plants are placed into net pots. The roots hang free in the water where
nutrient uptake occurs. Wongkiew et al. (2017) claimed that pak choi and lettuce
removed NO 3 by 84% and 67%, respectively. Wang et al. stated that water spinach
removed 80% of TAN by using this system. Marques et al. (2017) used flower plant,
Halimione portulacoides, in their system and 67% of N removal was attained in the
treatment of fish wastewater.
In summary, Estim et al. (2018), Wongkiew et al. (2017), Wang et al. (2016) and
Lam et al. (2015) used floating raft system in aquaponic biofilter system. This is
because the system is easy to set up, managed and monitored during the experiment.
In addition, the types of plants also play an important role in nutrient removal. This is
evident where flower plant, Nasturtium removed 89% of NH 3 −N. While vegetable
plant, water spinach removed 86% of NH 3 −N. This is because the flower plant was
able to stand higher temperatures up to 32 °C (Catley and Brooking 1996). Manarangi
et al. (1988) found that higher temperature increased the number of flowers and their
production rate. The efficiency of different systems used in previous studies including
the plants involved is summarised in Table 8.1.
123
According to Goddek (2017), there are several designs available for aquaponic
system. The designs are based on hydroponic systems, except that the water source
for the aquaponic system comes from the fish tank and is eventually returned to its
source of origin. There are three types of aquaponic systems, namely media filled
systems, nutrient film technique (NFT) and floating raft system. In media filled
system, the hydroponic component is distinguished first if it employs a media or
not. According to Estim et al. (2018), the system removed 59% PO 4 −N and 50%
NH 3 −N. Boxman et al. (2018) reported that Sesuvium portulacastrum (flower plant)
was able to remove 59% N from marine fish wastewater.
The second system is the nutrient film technique (NFT). This system consists of
the plant roots being exposed to a thin layer of nutrient water that runs through most
often a PVC pipe. Based on previous studies by Buzby and Lin (2014) and Endut
et al. (2010), these types of aquaponics needs a large area to build this system. In
Buzby and Lin (2014), the system was able to remove 81% of NH 3 −N by using
lettuce and 89% by nasturtium. Meanwhile, Endut et al. (2010) claimed that the
system removed total ammonia nitrogen (TAN) and total nitrogen (TP) by 86.22%
and 49.74%, respectively. The shallow flow of water only reaches the bottom of
the thick layer of roots that develops in the trough while the top of the root mass
is exposed to the air, thereby receiving an adequate oxygen supply. Channel slope,
length and flow rate must all be calculated to make sure the plants receive sufficient
water, oxygen and nutrients. If properly constructed, NFT can sustain very high plant
densities. In aquaponic NFT systems, the biofilter becomes crucial as there is no large
surface area whereby bacteria communities can develop.
The floating raft system is another type which has great potential for commercial
use in aquaponics (Wongkiew et al. 2017; Wang et al. 2016; Lam et al. 2015). The
system plants are grown on floating styrofoam rafts. The rafts have small holes cut
in them where plants are placed into net pots. The roots hang free in the water where
nutrient uptake occurs. Wongkiew et al. (2017) claimed that pak choi and lettuce
removed NO 3 by 84% and 67%, respectively. Wang et al. stated that water spinach
removed 80% of TAN by using this system. Marques et al. (2017) used flower plant,
Halimione portulacoides, in their system and 67% of N removal was attained in the
treatment of fish wastewater.
In summary, Estim et al. (2018), Wongkiew et al. (2017), Wang et al. (2016) and
Lam et al. (2015) used floating raft system in aquaponic biofilter system. This is
because the system is easy to set up, managed and monitored during the experiment.
In addition, the types of plants also play an important role in nutrient removal. This is
evident where flower plant, Nasturtium removed 89% of NH 3 −N. While vegetable
plant, water spinach removed 86% of NH 3 −N. This is because the flower plant was
able to stand higher temperatures up to 32 °C (Catley and Brooking 1996). Manarangi
et al. (1988) found that higher temperature increased the number of flowers and their
production rate. The efficiency of different systems used in previous studies including
the plants involved is summarised in Table 8.1.