Phosphorus removal from wastewater by field-scale fortified filter beds during a one-year study

• Due to low availability of alternative technologies, rural communities are unable to comply with national wastewater discharge limits. This study tested the effectiveness of filter bed fortification with biochar on phosphorus removal. Water-tight down-flow beds of sand and gas concrete, constructed alongside a reference sand bed (all 0.8 m deep and 0.75 m2 surface area), were topped with a 0.2 m biochar layer. Pre-treated domestic wastewater with mean concentrations of 6.4 mg/L PO3-4 and 142.6 NTU, was infiltrated at 4 cm/d hydraulic loading rate. Ultimately, the biochar-sand was relatively outstanding in turbidity reduction, achieving < 5 NTU. The biochargas concrete exhibited superior performance in PO3-4 removal, trapping 32.3 g (40.2%), compared with 20.5 g (25.6%) and 15.5 g (19.3%) by biochar-sand and reference bed respectively. However, statistical analysis revealed a weak correlation between pH and biochargas concrete removal efficiency (r2= 0.2). The relationship was stronger for biochar-sand PO3-4 (r2 = 0.5) than reference (r2 = 0.4) bed. Paired samples t-tests showed that incorporating biochar into the sand bed significantly (p =.04) improved its PO3-4 removal efficiency. In conclusion, sand bed fortification with biochar could be an important measure for improving P removal and wastewater clarification efficiency.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Naturresursteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Engineering (hsv//eng)

Nyckelord

Biochar

fortified filter beds

gas concrete

phosphorus removal

wastewater treatment

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)