Phosphorus Recovery from Wastewater: Bioavailability of P Bound to Calcareous Material for Maize (<i>Zea mays</i> L.) Growth

• Main Authors: Solvei M. Jensen, Chiara Esposito, Dennis Konnerup, Hans Brix, Carlos A. Arias
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Recycling
• Subjects: phosphorus recovery; P sorption; P bioavailability; calcareous material; circular economy; wastewater
• Online Access: https://www.mdpi.com/2313-4321/6/2/25

(1) Phosphorus (P) is an essential plant nutrient, and P deficiency negatively affects plant growth and development. Furthermore, P is a finite and nonrenewable resource, and there is an urgent need to recover P from some of the important waste streams in society. Newly engineered calcareous materials (sol–gel coated cat litter (CATSAN^®)) can bind P from wastewater in decentralized treatment systems and potentially enable P recycling into agricultural production by direct addition of the P saturated material. (2) The effects of the addition of two P-enriched calcareous materials as fertilizers for maize (<i>Zea mays </i>L.) growth were investigated in a mesocosm experiment. We compared fertilization with the P-enriched materials at rates of 6, 12, 25, 50, 100 kg P ha⁻¹ yr⁻¹ with fertilization with commercial NPK fertilizer. (3) The P fertilization by the P-enriched materials had a significant positive effect on plant height, biomass, maximum light-saturated photosynthetic rate, respiration rate, and total P content in biomass. However, plants fertilized by the commercial NPK fertilizer performed significantly better in the majority of measured parameters at identical fertilization rates. (4) The bioavailability of the P bound to the calcareous material was very low. However, the studied material has the potential to be used as part of a decentralized treatment solution to remove and subsequently recover and recycle P from wastewater.