Nitrifikasi separa (PN) adalah teknik yang berkesan untuk merawat kepekatan
tinggi ammonium dalam air sisa dengan menukar 50-57% daripada ammonium ke nitrit.
PN yang dijalankan oleh bakteria pengoksidaan Ammonium (AOB) adalah satu proses
yang sensitif kerana kadar pertumbuhan AOB yang jauh lebih rendah dan amat
bergantung kepada suhu, kepekatan substrat, kandungan oksigen dan pH, dan kehadiran
logam berat. Logam berat seperti nikel, zink, kadmium, dan plumbum yang memasuki
loji rawatan air sisa melalui pelepasan industri boleh memberi kesan kepada prestasi
nitrifikasi. Dalam kajian ini, kesan logam berat kepada biojisim berbutir dan biojisim
floccular telah dikaji berdasarkan kadar pengambilan oksigen (OUR), ammonia kadar
pengambilan (AUR) dan kadar pengambilan nitrogen (NUR). Biojisim berbutir dan
biomas floccular terkena Zn (II) dengan kepekatan di 0,3-1,2 mg / L dan Cu (II) dengan
kepekatan di 0,1-0,5 mg / L. Terdapat penurunan ketara dalam OUR dengan peningkatan
kepekatan Zn (II) dan Cu (II) di dalam berbutir dan biomas floccular. The AUR dan NUR
juga berkurangan apabila kepekatan logam berat kenaikan dalam berbutir dan biomas
floccular. Berdasarkan OUR, Cu (II) mula menghalang proses nitrifikasi separa pada
kepekatan melebihi 0.1 mg / L manakala Zn (II) pada kepekatan di atas 0.3 mg / L.
Keputusan keseluruhan menunjukkan bahawa kesan yang melarang daripada logam berat
kepada biomas floccular adalah lebih tinggi daripada biojisim berbutir. Oleh itu,
ketoksikan Cu (II) adalah lebih tinggi berbanding dengan Zn (II) di dalam berbutir dan
biomas floccular.
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Partial nitrification (PN) is an effective technique for treatment of high
concentrations of ammonium in wastewater by converting 50 - 57% of ammonium into
nitrite. PN is carried out by Ammonium oxidizing bacteria (AOB) is a sensitive process
because the growth rate of AOB is much lower and strongly dependent on temperature,
substrate concentration, oxygen content and pH, and the presence of heavy metals. Heavy
metals such as nickel, zinc, cadmium, and lead that enter wastewater treatment plants
through industrial discharge can give impact on nitrification performance. In this study,
the effect of heavy metals on granular biomass and floccular biomass carrying out PN
was study based on oxygen uptake rate (OUR), ammonia uptake rate (AUR) and nitrogen
uptake rate (NUR). The granular biomass and floccular biomass were exposed to Zn(II)
with concentrations at 0.3 - 1.2 mg/L and Cu(II) with concentrations at 0.1 – 0.5 mg/L.
There was significant decrease in OUR with increasing concentrations of Zn(II) and
Cu(II) in granular and floccular biomass. The AUR and NUR also decrease as
concentration of heavy metals increases in both granular and floccular biomass. Based on
OUR, the Cu(II) starts to inhibits the partial nitrification process at concentration above
0.1 mg/L while Zn(II) at concentration above 0.3 mg/L. Overall result show that the
inhibitory effects of heavy metals on floccular biomass is higher than in granular biomass.
Furthermore, the toxicity of Cu(II) is higher compared to Zn(II) in granular and floccular
Biomass.