Details

Autor(en) / Beteiligte

• Kwon, Gyutae
• Kang, Jinyoung
• Nam, Ji-Hyun
• Kim, Young-O.
• Jahng, Deokjin

Titel

Struvite production from anaerobic digestate of piggery wastewater using ferronickel slag as a magnesium source

Ist Teil von

• Environmental technology, 2021, Vol.42 (3), p.429-443

Ort / Verlag

England: Taylor & Francis

Erscheinungsjahr

2021

Quelle

Taylor & Francis Journals Auto-Holdings Collection

Beschreibungen/Notizen

• This study aimed to fully recover ammonia contained at a high concentration in anaerobic digestate of piggery wastewater (ADPW) by forming struvite. As magnesium and phosphorus sources, ferronickel slag (FNS) and K 2 HPO 4 were used, respectively. By leaching 200 g L −1 of FNS with 3.0 M H 2 SO 4 , 10,309 mg L −1 of magnesium ions were extracted, and this acid-leachate of FNS (FNSL) also contained 5965 mg L −1 of total iron. In order to simultaneously remove both high concentrations of organic matters in ADPW and iron in FNSL which were known to hinder struvite formation, the mixture of ADPW and FNSL was added with H 2 O 2 at the H 2 O 2 /Fe molar ratio of 0.75 and pH 4.0. After Fenton reaction, removal efficiencies of COD and total iron reached 77.36% and 99.89%, respectively. Then COD and an iron-reduced mixture of ADPW and FNSL were added with K 2 HPO 4 satisfying Mg:N:P molar ratio of 1.2:1:1.15 at pH 9.5 to produce struvite for 1 h. From 1 L of ADPW (2.21 g NH 3 -N), 0.65 L of FNSL (4.65 g Mg 2+ ), and 5.63 g of PO 4 3- P, 46.7 g of precipitates were obtained. Overall removal efficiencies of magnesium, NH 3 -N, and phosphorus were 98.59%, 94.25%, and 99.97%, respectively. Obtained precipitates were analysed by using XRD, XRF, SEM-EDX and found to be struvite with impurities of potassium and metals. Additionally, the economic feasibility of FNS was assessed by estimating chemical costs of various magnesium sources.