Green Synthesis of Fe3O4@Carbon
Filter Media for Simultaneous Phosphate Recovery and Nitrogen Removal
from Domestic Wastewater in Biological Aerated Filters
posted on 2019-09-06, 19:37authored byTeng Bao, Mekdimu Mezemir Damtie, Zhi Min Yu, Yiwen Liu, Jie Jin, Ke Wu, Cheng Xun Deng, Wei Wei, Xing Lai Wei, Bing-Jie Ni
Domestic
wastewater depth processing and reclamation are essential
in the alleviation of global water shortage. In this study, an innovative
filter media (i.e., Fe3O4@Carbon filter media
[FCM]) was synthesized and subsequently used in a biological aerated
filter (BAF) for simultaneous phosphate recovery and nitrogen removal
(SPN) from domestic wastewater. The performance of FCM was compared
with the commercially available ceramsite (CAC). The results showed
that the performance of FCMBAF was better than that of CACBAF; as
far as SPN is concerned, the magnetic field of FCMBAF could accelerate
the growth rate of biofilm. Moreover, the nitrospira and nirK gene
copy numbers of FCMBAF were considerably higher than those of CACBAF.
Interestingly, the interconnectivity and uniformity of pores were
also suitable for the microdistribution of biofilm, where different
aerobic and anaerobic zones of the FCM were formed. This facilitates
the microinteraction between the key microorganisms and the filter
media that successfully enhanced the nitrogen removal. The phosphate
recovery was attained via hydroxyapatite (Ca10(PO4)6(OH)2) formation, which resulted from the
reaction between phosphate (PO43–) and
FCM. The average effluent concentrations of total organic carbon (TOC),
total nitrogen (TN), ammonia nitrogen (NH4+-N),
and PO43– were 8.12, 6.18, 0.997, and
0.073 mg/L of FCMBAF, respectively, which were lower than those from
the national standard (CODcr ≤ 50 mg L–1, NH4+-N ≤ 5.0 mg L–1, TN ≤ 15 mg L–1, TP ≤ 0.5 mg L–1, GB 18918–2002, first standard). Thus, FCM
demonstrated a promising potential for SPN and wastewater recycling
of BAF in domestic wastewater treatment.