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

Abstract

(1) Phosphorus (P) removal has proven difficult in decentralized wastewater treatment systems, and external filters installed with a highly P sorbent material have been proposed to improve the P removal. In particular, calcium (Ca) rich materials have shown promising results. (2) Eight materials (five calcareous materials, one quartz sand, and two Sol–Gel coated calcareous materials) were tested in columns fed with P-spiked tap water for two years. The experiment was operated under four periods with increased P concentration from 3.3 to 21.5 mg P L−1, and with increased surface loading rate from 18 to 227 mm d−1. After termination, the element content was measured in four column height fractions. (3) Initially, all columns removed P effectively and the calcareous materials (CAT, CAT A, and CAT C) maintained an effective removal until termination, while increases in effluent P concentration were detected already after 7 weeks for SAN and after 80–90 weeks for OPO, PHO, CAL, and HYG. The highest P content for materials were measured for the bottom fraction closest to the inlet distribution. For most materials, we observed a good agreement between the maximum sorption capacity (Qmax) and the P content in the bottom fraction; however, a discrepancy was observed for CAL, CAT A, and CAT C. (4) In conclusion, the calcareous materials provided a consistent P removal for all 24 months. Additionally, the Sol–Gel coating had a minimal effect on the P removal capacity contrary to previous findings in batch experiments for the coated materials.

Assessment of Recycled and Manufactured Adsorptive Materials for Phosphate Removal from Municipal Wastewater

“…Expanded clay decreased in removal capacity over the 20‐week duration (from 91 to 42% removal), while RCA maintained consistent removal. Jensen et al (2022) achieved similar (up to 100%) P removal in columns containing a variety of calcareous materials, with P inputs ranging from 3 to 22 mg P/L. Ádám et al (2007) demonstrated above 90% P removal from a 10 mg P/L‐amended secondary wastewater solution within columns containing expanded clay, with average HRTs of around four days.…”

White Cement as a Nontoxic and Eco-Friendly Adsorbent for Phosphate Adsorption/Desorption: Characterization, Optimization, and Modeling Studies

“…Fixed-bed column is a technique used to reproduce the adsorption process close to reality, aiming for full-scale applications. This type of system is one of the most effective configurations for treating large volumes of effluents, allowing more efficient use of the adsorbent. , Biochar, electrochemically modified with ferric sludge, iron oxide, calcium alginate, recycled steel byproducts, porous alginate, acrylic amine fiber, hydrated granulated ferric oxide, limestone materials, and concrete powder are among the adsorbents used in fixed-bed column experiments for phosphate removal. However, there are no studies using WC as an adsorbent in fixed-bed columns, reinforcing the novelty of this study regarding phosphate adsorption.…”