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Effects of heavy metals on partial nitrification

Effects of heavy metals on partial nitrification / Nur Athirah Azhar

Abstract 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. _______________________________________________________________________________________________________ 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.

Contributor(s): Nur Athirah Azhar - Author Primary Item Type: Final Year Project Identifiers: Accession Number : 875008127 Language: English Subject Keywords: Partial nitrification; ammonium; (AOB) First presented to the public: 6/1/2019 Original Publication Date: 6/27/2019 Previously Published By: Universiti Sains Malaysia Place Of Publication: School of Chemical Engineering Citation: Extents: Number of Pages - 60 License Grantor / Date Granted:   / ( View License ) Date Deposited 2019-06-27 15:25:49.295 Submitter: Mohd Jasnizam Mohd Salleh

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