Phosphorus Recovery from Wastewater: Bioavailability of P Bound to Calcareous Material for Maize (Zea Mays L.) Growth

Abstract

(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 (Zea mays 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.

The Effect of Sol-Gel Coatings on the Phosphorus (P) Adsorption Capacity of Calcareous Materials for Use in Water Treatment

“…The sorption process constitutes a relatively simple and passive method to overcome P removal limitations in these systems, as when it is installed the material will bind P without much interference when compared to chemical dosing for P removal by precipitation or by harvest of plant biomass. The P saturated material could ideally be used directly as soil amendment and for slow release of P [13,14].…”

Study on the Recycling of P in Phosphogypsum Leachate

“…The first is the recovery of phosphorus from the liquid phase, which is only 50% -60%. No one has given an explanation for the reasons behind the low efficiency of recovering P from phosphogypsum or the fact that in actuality, regardless of the original phosphorus content, the residual phosphorus concentration always stays within a specific set range (Jensen et al, 2021). This study will mathematically calculate this range to obtain a specific set range as well as to explain the presence of residual phosphorus.…”

Sustained Phosphorus Removal by Calcareous Materials in Long-Term (Two Years) Column Experiment

“…The external filter would polish effluent from the TWs by removing the excess P, but also allow a straightforward material exchange once the filter material has become P saturated, in comparison to exchanging the entire main bed of the TW. Another advantage of the external filter is its ability to make P more accessible for reuse and research has indeed already shown the potential use of P-enriched filter materials as a slow-release P fertilizer [16,17]. The recovery of P is important, as P is a limited and non-renewable resource [18,19], but also an essential plant nutrient with P deficiency negatively affecting plant growth [20].…”