Granular biochar compared with activated carbon for wastewater treatment and resource recovery

• Published in: Water research (Oxford) Vol. 94; pp. 225 - 232
• Main Authors: Huggins, Tyler M., Haeger, Alexander, Biffinger, Justin C., Ren, Zhiyong Jason
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2016
• Subjects: Activated carbon; Adsorption; Biochar; Biological Oxygen Demand Analysis; Calcium - analysis; Charcoal - chemistry; Column packings; Columns (structural); Filtration; Magnesium - analysis; Metals, Heavy - analysis; Nutrient recovery; Nutrients; Oxygen demand; Phosphorus - analysis; Potassium - analysis; Recovery; Sustainability; Waste Disposal, Fluid - methods; Waste Water - chemistry; Wastewater; Wastewater treatment; Wood; Biochar; Wastewater; Activated carbon; Nutrient recovery; Sustainability
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2016.02.059

Granular wood-derived biochar (BC) was compared to granular activated carbon (GAC) for the treatment and nutrient recovery of real wastewater in both batch and column studies. Batch adsorption studies showed that BC material had a greater adsorption capacity at the high initial concentrations of total chemical oxygen demand (COD-T) (1200 mg L−1), PO4 (18 mg L−1), and NH4 (50 mg L−1) compared to GAC. Conversely the BC material showed a lower adsorption capacity for all concentrations of dissolved chemical oxygen demand (COD-D) and the lower concentrations of PO4 (5 mg L−1) and NH4 (10 mg L−1). Packed bed column studies showed similar average COD-T removal rate for BC with 0.27 ± 0.01 kg m−3 d−1 and GAC with 0.24 ± 0.01 kg m−3 d−1, but BC had nearly twice the average removal rate (0.41 ± 0.08 kg m−3 d−3) compared to GAC during high COD-T concentrations (>500 mg L−1). Elemental analysis showed that both materials accumulated phosphorous during wastewater treatment (2.6 ± 0.4 g kg−1 and 1.9 ± 0.1 g kg−1 for BC and GAC respectively). They also contained high concentrations of other macronutrients (K, Ca, and Mg) and low concentrations of metals (As, Cd, Cr, Pb, Zn, and Cu). The good performance of BC is attributed to its macroporous structure compared with the microporous GAC. These favorable treatment data for high strength wastewater, coupled with additional life-cycle benefits, helps support the use of BC in packed bed column filters for enhanced wastewater treatment and nutrient recovery. [Display omitted] •Granular biochar can be a new low-cost alternative to biological activated carbon.•The macroporous biochar allows increased organic removal, nutrient recovery.•The biochar biofilter is less prone to fouling due to more optimized pore structure.