A mobile pilot scale plant for in situ demonstration of phosphorus recovery from wastewater using amorphous calcium silicate hydrates
Abstract A mobile pilot scale plant was developed for the in situ examination and demonstration of phosphate (P i recovery from wastewater. The mobile pilot plant consisted of a 1000 L reinforced plastic reactor, a self made filter, and ancillary equipment and was set up on a 1.5 tonne motor truck for transport. Five separate in situ experiments were carried out using the mobile pilot plant to evaluate the ability of amorphous calcium silicate hydrates (A CSHs) to recover P i from anaerobic sludge digestion liquor at a wastewater treatment plant. On average, approximately 80% P i could be recovered from the anaerobic sludge digestion liquor by a process consisting of 20 min mixing, 30 min settling, and 90 min filtration. Approximately 20% of the dry weight of the recovered product was citrate soluble P 2 O 5 The levels of heavy metals such as Cd, As, Pb, Ni, and Cr were much lower than their regulatory standards for fertilizer. The efficacy of the recovered product as P i fertilizer was confirmed by plant cultivation tests using the leaf vegetable Komatsuna Brassica rapa L. var. perviridis The present study showed that the mobile pilot plant is useful as a simple, potentially low cost tool for the in situ examination and demonstration of P i recovery from wastewater.