Adsorptive Resource Recovery from Human Urine: System Design, Parametric Considerations and Response Surface Optimization. (2016)

• Record Type: Journal Article
• Authors: Simha, Prithvi; Banwasi, Paurush; Mathew, Melvin; Ganesapillai, M.
• Is Part Of: Procedia engineering. Volume 148(2016)
• Page Start: 779
• Page End: 786
• Publication Date: 2016
• Subjects: Column adsorption -- Immobilization -- Packed bed column -- Activated carbon -- Wastewater -- Ecological sanitation; Engineering -- Congresses; Engineering -- Periodicals; Engineering; Conference proceedings; Periodicals; 620.005
• DOI: 10.1016/j.proeng.2016.06.557
• Languages: English
• ISSNs: 1877-7058

Abstract

Abstract: Despite its high concentration, potential availability and hence, potential reusability of nutrients, human urine continues to be flushed away in our toilets. The poor management of nutrients in our built environment in lieu of the representative failures in our systems to safely handle, treat and assimilate these 'waste' resources has resulted in considerable environmental externalities. Adsorption systems that utilize agro–waste sourced carbon as an adsorption media have shown promise in recovering plant–required nutrients from urine. This study details the applicability of two continuously operated columns for stripping urea from urine for subsequent use as fertilizers. The first column was packed with prepared carbon at various bed heights (10–50 cm) and the second column had carbon immobilized over etched glass beads of various support sizes (1.5–2.5 cm). By using a Box–Behnken design and Response Surface Methodology (RSM), the system was optimized with the objective of maximizing column capacities. For the packed bed, maximum sorption of 0.116 g.g –1 occurs at inlet flow rate of 6 L.h –1, concentration of 100% and carbon bed depth of 30 cm; in the immobilized bed, the optimal parameters were identified as flow rate of 10 L.h –1, 100% initial urea concentration and support size of 1.5 cm to yield capacity of 0.328 g.g –1 . Immobilization as a pre–treatment in column design was significantly advantageous in recovering higher amount of urea at lesser activated carbon input relative to the packed bed. RSM was found to be an effective tool for selecting the process parametric inputs, in describing their effects on the operation of the column and in maximizing the urea recovery.