Agriculture Reference
In-Depth Information
12.5 Combined Use of Anaerobic Microorganisms
and Titanium Dioxide for the Removal of Antibiotics
from Aquaculture Wastewater
12.5.1 Conventional Farming Wastewater Treatment
Process
In recent years, to shorten the growth cycle of livestock farming, increase produc-
tion, and reduce costs, large-scale livestock breeding industry has been rapidly
developing worldwide. However, large-scale livestock farming not only produces
large volumes of animal wastewater that can pollute the surface of water bodies,
causing environmental problems such as eutrophication, but also deteriorates the
groundwater quality and ecosystem diversity and even endangers human health.
The characteristics of livestock wastewater are high chemical oxygen demand
(COD), suspended solids (SS), and ammonia nitrogen (NH
3
-N) content; good
biodegradability and precipitation performance; variation in water quality and
quantity; presence of pathogens; and fetid nature. To control the direct discharge
of livestock wastewater into the environment, various livestock wastewater treat-
ment technologies are being employed, which can be broadly divided into physico-
chemical technology and biological technology.
12.5.2 Physicochemical Technology
The common physicochemical methods include absorption, magnetic flocculation,
electrochemical oxidation, and Fenton oxidation. The basis for adsorption is selec-
tion of the adsorption medium; currently, zeolite is used as the adsorption medium.
In a previous study, increases in the uptake of enrofloxacin onto natural zeolite were
obtained by decreasing the pH and increasing the temperature. Also, increasing the
ammonia concentration from 50 to 200 mg/L resulted in 50 % increase in the
adsorption of enrofloxacin (
¨
tker and Akmehmet-Balcıo
˘
lu
2005
). Furthermore,
wastewater can be treated by employing magnetic flocculation separation using
magnetic seed and flocculants. This process is straightforward with good
settleability and a short processing cycle, but can generate a large amount of
chemical sludge. Fenton oxidation is effective in removing higher COD and color
(Lee and Shoda
2008
) and can be used as an advanced treatment of livestock
wastewater, despite the requirement of a large amount of Fe
2+
dosage and low
H
2
O
2
removal efficiency. Thus, these physicochemical treatment methods can
remove COD, NH
3
-N, and the color of livestock wastewater and can be applied
to livestock wastewater as pretreatments or advanced treatments. Nevertheless,
further research on this technology is still required because of the lack of engineer-
ing knowledge.
