Biological release of phosphorus is more efficient from activated than from aerobic granular sludge

Abstract

Sewage sludge is a rich source of phosphorus. The kinetics of orthophosphate release and the efficiency of phosphorus recovery from aerobic granular sludge (GS) and activated sludge (AS) were compared at external organics (F) to biomass (M) ratios that ranged from 0 to 0.10. Changes in the F/M ratio affected orthophosphates release from AS to a greater extent than their release from GS. On average, increasing the F/M ratio by 0.02 increased the rate of phosphorus release from AS and GS by 2.12 and 1.75 mg P/(L h), respectively. Phosphorus release was highest at an F/M ratio of 0.04 (114.03 and 60.71 mg P/L from AS and GS, respectively). The efficiency of phosphorus recovery from AS ranged from 51.3 to 56.1%; the efficiency of its recovery from GS ranged from 32.8 to 37.5%. From GS, mostly inorganic phosphorus was released (about 8.5 mg/g MLSS), most of which was NAIP, i.e. phosphorus bound to Fe, Mn and Al. At a stoichiometric dose of MgO to PO43−, the precipitation efficiency was 30.13% ± 4.51 with uncontrolled pH and reached 81.73% ± 0.17 at a controlled pH of 10.

Biological recovery of phosphorus (BioP‐Rec) from wastewater streams using brewer's yeast on pilot‐scale

“…An economically viable free P concentration of at least 0.05 kg/m 3 was achieved most rapidly when citric acid was added in stage 1 to assist P release to 0.106 kg/m 3 within 30 min (Figure 2A , experiment 2). Free P release was found to be lower with lower initial dosage of citric acid (experiment 1), similarly as reported for sludge acidification with acetic acid [ 33 , 34 , 35 ]. The reason for the faster free P release at lower pH is probably that low pH might lead to toxification from undissociated acid penetrating bacterial cell membranes [ 35 ].…”

Evaluation and removal efficiencies of a rural WWTP for metals and anions in Lufkin, East Texas (USA)

“…The macroelement concentrations in the anaerobic sludge follow the order: P (1119.47 ± 112.34 mg/kg) > Na (691.19 ± 303.37) > Fe (355.73 ± 135.57) > Al (355.25 ± 145.06) > K (235.51 ± 21.13) > Ca (192.61 ± 145.06) > S (275.34 ± 112.34) > Mg (77.22 ± 28.50). Previous results from other WWTPs showed phosphorus accounts for the greater percentage of macro-elements in the influent wastewater (Cydzik-Kwiatkowska & Nosek, 2020 ; Kehrein et al, 2020 ; Li et al, 2019 ).…”

Electrodialytic Remediation of Toxic Elements and P Recovery from Sediments of Eutrophic Fresh-Waters in 3-Compartment Batch and Stack Setup

“…All three sediments had higher P content than average contents of agricultural soils, which range between 500-800 mg P/kg [18], and thus are valuable in the efforts to recover and recycle P. The Bygholm sediment, which was sampled in an agricultural area, had the highest P content. However, the P content of the three sediments was a size order lower than that of wastewater sludge, which ranges between 10-40 g/kg [19][20][21], showing that despite holding a significant P resource, lake sediments are not the most essential source. The Bagsvaerd sediment was lower in TOC compared to the two other, and also more coarse-grained, indicating that P, TOC, and fine-grained structure are somewhat positively correlated characteristics.…”