Producing Superphosphate with Sewage Sludge Ash: Assessment of Phosphorus Availability and Potential Toxic Element Contamination

Recovering and recycling phosphorus (P) from sewage sludge ash (SSA) for the purpose of P fertilizer production contributes to reducing the input of mined phosphate-minerals and closing of the P cycle. However, direct use of SSA as fertilizer is often a questionable strategy due to its low nutrient use efficiency. In addition, the environmental risk potential of utilizing SSA in agriculture is still unclear, in particular potential toxic element (PTE) contamination. In this study, a mixture of SSA and rock phosphate was used at lab-scale superphosphate (SP) production. P availability of the final product and PTE contamination (Cd, Cr, Cu, Zn, Pb, Ni) in soil and crop was investigated through maize (Zea mays L.) cultivation. Results showed that the application of SP that was produced by 25% SSA replacement did not affect the growth, P uptake, and PTE content in aboveground maize compared to the application of SP produced without SSA replacement. However, significant inputs of SP with SSA replacement may decrease the solid-soil solution partitioning of Cu, Ni and Pb in the long-term. Separation of municipal/industrial sludge and PTE removal technology are necessary to be implemented prior to the use of SSA as a secondary raw material in P-fertilizer production.

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Thermochemical Treatment of Sewage Sludge Ash (SSA)—Potential and Perspective in Poland

Energies ◽

10.3390/en13205461 ◽

2020 ◽

Vol 13 (20) ◽

pp. 5461

Author(s):

Marzena Smol ◽

Christian Adam ◽

Stefan Anton Kugler

Keyword(s):

Sewage Sludge ◽

Raw Materials ◽

Thermochemical Treatment ◽

Raw Material ◽

Ammonium Citrate ◽

Municipal Sewage Sludge ◽

Mineral Fertilizers ◽

Sewage Sludge Ash ◽

Fertilizer Production ◽

Sludge Ash

Phosphorus (P) recovery from sewage sludge ash (SSA) is one of the most promising approaches of phosphate rock substitution in mineral fertilizers and might be a sustainable way to secure supply of this raw material in the future. In the current investigation, the process of thermochemical treatment of SSA was applied to SSA coming from selected mono-incineration plants of municipal sewage sludge in Poland (Cracow, Gdansk, Gdynia, Lodz, Kielce and Szczecin). The Polish SSA was thermochemically converted in the presence of sodium (Na) additives and a reducing agent (dried sewage sludge) to obtain secondary raw materials for the production of marketable P fertilizers. The process had a positive impact on the bioavailability of phosphorus and reduced the content of heavy metals in the obtained products. The P solubility in neutral ammonium citrate, an indicator of its bioavailability, was significantly raised from 19.7–45.7% in the raw ashes and 76.5–100% in the thermochemically treated SSA. The content of nutrients in the recyclates was in the range of 15.7–19.2% P2O5, 10.8–14.2% CaO, 3.5–5.4% Na2O, 2.6–3.6% MgO and 0.9–1.3% K2O. The produced fertilizer raw materials meet the Polish norms for trace elements covered by the legislation: the content of lead was in the range 10.2–73.1 mg/kg, arsenic 4.8–22.7 mg/kg, cadmium 0.9–2.8 mg/kg and mercury <0.05 mg/kg. Thus, these products could be potentially directly used for fertilizer production. This work also includes an analysis of the possibilities of using ashes for fertilizer purposes in Poland, based on the assumptions indicated in the adopted strategic and planning documents regarding waste management and fertilizer production.

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Thermochemical treatment of sewage sludge ash with sodium salt additives for phosphorus fertilizer production – Analysis of underlying chemical reactions

Waste Management ◽

10.1016/j.wasman.2015.07.029 ◽

2015 ◽

Vol 45 ◽

pp. 385-390 ◽

Cited By ~ 29

Author(s):

Jan Stemann ◽

Burkhard Peplinski ◽

Christian Adam

Keyword(s):

Sewage Sludge ◽

Chemical Reactions ◽

Sodium Salt ◽

Thermochemical Treatment ◽

Phosphorus Fertilizer ◽

Sewage Sludge Ash ◽

Fertilizer Production ◽

Production Analysis ◽

Sludge Ash

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Critical Evaluation of the Agronomic Effectiveness of Recovered Phosphate Fertilizer Produced From Incinerated Sewage Sludge Ash

10.21203/rs.3.rs-709653/v1 ◽

2021 ◽

Author(s):

Le FANG ◽

Qiming Wang ◽

Jiang-shan Li ◽

Chi Sun Poon

Keyword(s):

Sewage Sludge ◽

Plant Growth ◽

Critical Evaluation ◽

Phosphate Fertilizer ◽

P Availability ◽

Agronomic Effectiveness ◽

Sewage Sludge Ash ◽

P Recovery ◽

Sludge Ash ◽

P Fertilizers

Abstract Phosphorus (P) recovery from incinerated sewage sludge ash (ISSA) has been extensively investigated, and various recovered phosphate fertilizers (RPFs) have been produced. In this study, three RPFs (calcium phosphate compounds (CaP), struvite (SP), and P-loaded biochar (BP)) produced from ISSA were characterized and their agronomic effectiveness were verified by pot experiments with the cultivation of choy sum (Brassica campestris L. ssp. Chinensis var. utillis Tsen et Lee) and ryegrass (Lolium perenne L.). The SP has the highest P purity while the BP has the most complex P species. And the plant growth results showed that the RPFs greatly facilitated plant growth and demonstrated superior/comparable effects to those of MP/CoF. In general, choy sum fertilized with SP showed the best effect due to the Mg involved and the high P purity of SP, while ryegrass fertilized with BP performed the best among all of the groups because of the additional nutritional elements and the high P availability of BP. Additionally, the accumulation of heavy metals in the plants under all conditions did not exceed the limits stipulated in the regulations. These results indicate that recovering P from ISSA is an attractive technology to produce P fertilizers, which can alleviate both the scarcity of phosphate resources and the burden of ISSA management.

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Clinkering of Sewage Sludge Ash as Cement Raw Material

Journal of the Korean Ceramic Society ◽

10.4191/kcers.2004.41.4.323 ◽

2004 ◽

Vol 41 (4) ◽

pp. 323-327

Keyword(s):

Sewage Sludge ◽

Raw Material ◽

Sewage Sludge Ash ◽

Sludge Ash ◽

Cement Raw Material

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Feasibility of wet-extraction of phosphorus from incinerated sewage sludge ash (ISSA) for phosphate fertilizer production: A critical review

Critical Reviews in Environmental Science and Technology ◽

10.1080/10643389.2020.1740545 ◽

2020 ◽

pp. 1-33 ◽

Cited By ~ 2

Author(s):

Le Fang ◽

Qiming Wang ◽

Jiang-shan Li ◽

Chi Sun Poon ◽

C. R. Cheeseman ◽

...

Keyword(s):

Sewage Sludge ◽

Critical Review ◽

Phosphate Fertilizer ◽

Sewage Sludge Ash ◽

Fertilizer Production ◽

Sludge Ash

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Using an Environment-Friendly Fertiliser from Sewage Sludge Ash with the Addition of Bacillus megaterium

Minerals ◽

10.3390/min9070423 ◽

2019 ◽

Vol 9 (7) ◽

pp. 423 ◽

Cited By ~ 3

Author(s):

Magdalena Jastrzębska ◽

Marta K. Kostrzewska

Keyword(s):

Sewage Sludge ◽

Bacillus Megaterium ◽

Heterotrophic Bacteria ◽

Plant Protection ◽

Raw Materials ◽

Raw Material ◽

Test Plant ◽

Sewage Sludge Ash ◽

Bacteria And Fungi ◽

Sludge Ash

Sewage sludge ash (SSA) is considered to be a valuable secondary raw material for the production of phosphorous fertilisers. This method of recycling may also be a solution to the problem posed by the growing amount of this waste. An innovative suspension fertiliser (SSAB) was produced from SSA and the phosphorus-solubilising bacteria Bacillus megaterium and was tested in a field experiment in the presence of spring wheat as the test plant in comparison to conventional fertilisers (superphosphate, phosphorite). Two variants of plant protection were also adopted: full chemical plant protection (+PP) and no plant protection (−PP). Besides affecting yield, it was expected that SSAB would not worsen the state of the soil environment. This paper presents SSAB effect on soil moisture and temperature, soil pH, content of toxic elements (As, Cd, Cr, Ni and Pb) in the soil, abundance of heterotrophic bacteria and fungi and the occurrence of earthworms. SSAB did not affect the tested soil characteristics when applied in reasonable doses. Plant protection had an individual effect on soil properties but did not modify the fertiliser action. SSAB may be a potential substitute for P fertilisers produced from non-renewable raw materials in times of shortage. Further long-term research is recommended to confirm these findings.

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