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SEMERCİ, NESLİHAN

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2017 - 201922020 - 20221
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Subject: Phosphorus recovery ×

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Now showing 1 - 3 of 3
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    Phosphorus Recovery from Waste Activated Sludge: Microwave Treatment and Ozonation with Acid & Alkaline Pre-treatments
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2017) SEMERCİ, NESLİHAN; Cosgun, S.; Semerci, N.; Mannina, G
    This study investigated phosphorus recovery from activated sludge through ozonation and microwave treatment with acid and alkali pre-treatments. Three main groups (pH treatment & ozonation, pH treatment & microwave, pH treatment & ozonation & microwave) were studied for COD and P release. Results of batch experiments have shown that, optimum pH for sludge disintegration and phosphorus release is 10 according to center dot OH radical formation. Also studying at low pH levels gives an advantage due to effect of acidic condition on cell lysis. Besides, according to results of phosphorus fraction experiments in raw sludge, the other advantage of low pH levels is releasing of apatite (bound to calcium) phosphorus. Both ozonation and microwave treatments were effective for sludge disintegration, the highest COD release was observed after microwave treatment of ozonated samples. However, microwave was much more effective than ozonation on phosphorus, significant amount of phosphorus released into the bulk solution in both ozonation and microwave treatments. Despite of COD release, microwave and ozonation & microwave have similar efficiencies on phosphorus release, ozonation might be negligible before microwave due to high production cost. On the other hand, after analyses of struvite samples, pH = 8.5 and 2 days reaction time was determined as the optimum conditions for struvite purity.
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    Phosphorus recovery from sewage sludge ash with bioleaching and electrodialysis
    (ELSEVIER SCI LTD, 2019) ÇALLI, BARIŞ; Semerci, Neslihan; Kunt, Busra; Calli, Baris
    Phosphorus is an essential element for all living organisms and for plants. However, phosphate rock, which is the main source of phosphorus, is limited and thus it must be recovered from secondary sources like sewage sludge ash (SSA). SSA is one of the most promising secondary sources because it contains considerable amounts of phosphorus. The drawback of SSA as a secondary source is the presence of heavy metals along with phosphorus. In this study, a bioleaching process was applied to solubilize the phosphorus more economically, thus bioleaching bacteria was used to obtain acidic conditions for phosphorus leaching. For this purpose, batch bioleaching experiments were carried out with Sulfur oxidizing bacteria (SOB) to optimize the process in terms of phosphorus dissolution. Experiments were conducted with different amounts of ash, inoculum volumes, and sulfur concentrations. Because the application of the bioleaching process leads to solubilization of heavy metals beside phosphorus, an electrodialysis process was used to separate phosphorus from heavy metals. Electrodialysis experiments were performed in a 3 compartment electrodialysis reactor with gold coated copper electrodes. The maximum phosphorus bioleaching was obtained with 2 g of ash, 40% inoculum, and 10 g.l(-1) elemental sulfur. Electrodialysis studies with gold coated copper electrodes lasted for 14 days and 24.6% of the phosphorus was transported to the anode.
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    Biological recovery of phosphorus from waste activated sludge via alkaline fermentation and struvite biomineralization by Brevibacterium antiquum
    (2022-04-01) SEMERCİ, NESLİHAN; Cosgun S., Kara B., Kunt B., Hur C., SEMERCİ N.
    Struvite biomineralization is a promising method for phosphorus recovery from wastewater treatment plant streams, and the growth of responsible microorganisms in mixed cultures is one of the most critical points for applying this process in pilot and full-scale. This study aimed to investigate the growth and bio-struvite production of Brevibacterium antiquum in mixed sludge culture. Alkaline fermentation was applied at different pH conditions to enhance the phosphorus content of sludge for an efficient recovery, and pH 8 was determined as the most feasible considering the phosphorus release and sludge characteristics. Growth optimization studies showed that NaCl\"s presence decreases the growth rate of Brevibacterium antiquum and bio-struvite production. At the same time, pH in the range of 6.8-8.2 did not alter the growth significantly. In addition, studies showed the ability of Brevibacterium antiquum in unsterilized fermented sludge centrate to grow and recover the phosphorus as struvite. Thus, our results indicated the potential of struvite biomineralization in full-scale wastewater treatment plants.