Understanding the growth of the bio-struvite productionBrevibacterium antiquumin sludge liquors

Abstract

Biological struvite (bio-struvite) production through biomineralization has been suggested as an alternative to chemically derived struvite production to recover phosphorus from wastewater streams. In this study, statistical experimental design techniques were used to find the optimal growth rate (μ) of Brevibacterium antiquum in sludge liquors. Acetate, oleic acid, NaCl, NH-N, and Ca were shown to affect the growth rate of B. antiquum. The growth rate reached 3.44 1/d when the bacteria were supplemented with 3.0% w/v NaCl and 1124 mg chemical oxygen demand/L as acetate. However, NaCl was found to hinder the biomineralization of bio-struvite. A two-stage experiment demonstrated that bio-struvite was produced in the presence of acetate. Bio-struvite production was confirmed with X-ray spectroscopy and crystal morphology (prismatic, tabular, and twinned crystal habit) through electron microscope analysis. The bio-struvite production was estimated by measuring phosphate content of the recovered precipitates, reaching 9.6 mg P/L as bio-struvite. Overall, these results demonstrated the optimal conditions required to achieve high growth rates as well as bio-struvite production with B. antiquum. The results obtained in this study could be used to develop a process to grow B. antiquum in wastewater streams in mixed cultures and recover phosphorus-rich products such as struvite.

Recovery of phosphorus as soluble phosphates from aqueous solutions using chitosan hydrogel sorbents

“…In the experimental series with CHs-ECH, an increase in solution’s pH during i-PO 4 sorption was not that high as in the case of CHs, which caused retardation and lesser intensity of ion release. After too long contact of the sorbent with the source solution, the phenomenon of orthophosphate desorption was also observed during nutrients removal from multi-component solutions 17 .…”

“…There is also the possibility of biological struvite precipitation using dedicated bacteria, like e.g., Myxococcus xanthus 16 , which allow producing its crystals. In turn, the use of Brevibacterium antiquum results in the formation of magnesium phosphate crystals 17 . Currently, this process is effective only under strictly controlled laboratory conditions.…”

Understanding the biochemical characteristics of struvite bio-mineralising microorganisms and their future in nutrient recovery

“…It was reported that the increased NaCl could increase the solubility of the struvite phase and therefore lead to inhibition of the bio-struvite crystal size (Rivadeneyra et al, 2006). Significant prevention of bio-struvite production was also observed on sludge dewatering liquors with 3% w/v NaCl (Simoes et al, 2017). The molar ratio of the removed PO 4 -P to Mg 2+ by B. antiquum under aerobic conditions ([PO 4 -P]/[Mg 2+ ] =1.4) was relatively higher than the standard stoichiometric ratio [PO 4 -P]/[Mg 2+ ] of struvite, indicating that B. antiquum may absorb considerable amounts of PO 4 -P into cells.…”

“…Ca concentration was adjusted to 28 mg/L (Gassama et al, 2015). The NaCl content varied between 0.5-3.5% w/v, based on characterisation of municipal wastewater and sludge dewatering liquors in different full scale sites in the UK (Simoes et al 2017). (Table S1).…”

“…Statistical experimental design is recognised as an approach widely used for parameter screening in optimisation studies (Massey et al, 2009). By using such design, Simoes et al (2017) investigated the significant factors required for B. antiquum growth, and maximised the growth rates in wastewater streams by screening and optimising a number of factors.…”