Utilization of sewage sludge in EU application of old and new methods—A review
TL;DR: In this article, the authors review past and future trends in sludge handling, focusing mainly at thermal processes (e.g. pyrolysis, wet oxidation, gasification) and the utilization of sewage sludge in cement manufacture as a co-fuel.
Abstract: The European Union has made progress in dealing with municipal wastewater in individual countries and as a corporate entity. However, it intends to make still further and substantial progress over the next 15 years. Currently, the most widely available options in the EU are the agriculture utilization, the waste disposal sites, the land reclamation and restoration, the incineration and other novel uses. The selection of an option on a local basis reflects local or national, cultural, historical, geographical, legal, political and economic circumstances. The degree of flexibility varies from country to country. In any case sludge treatment and disposal should always be considered as an integral part of treatment of wastewater. There is a wide range of other uses for sludge, which exploit its energy or chemical content, namely the thermal processes. The present paper sought to review past and future trends in sludge handling, focusing mainly at thermal processes (e.g. pyrolysis, wet oxidation, gasification) and the utilization of sewage sludge in cement manufacture as a co-fuel.
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TL;DR: The fixed bed reaction under partial oxidation conditions can be applied to produce biochar as soil ameliorator from the sludge briquettes without external heat supply.
18 citations
Cites background from "Utilization of sewage sludge in EU ..."
...Themainmethod for energy recovery from the sewage sludge by thermal treatment is incineration in a dedicated facility or cocombustion in an existing fossil fuel-fired furnace such as a coalfired power plant or cement kiln (Fytilim and Zabaniotou, 2008)....
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TL;DR: In this paper, the authors investigated the hydrothermal conversion of underutilized waste streams for biomass feedstock, and they used cooking oil to form a waste slurry that was thermally converted to renewable fuel products.
17 citations
TL;DR: This research tested the feasibility of torrefaction of SS with high ash content for either fuel or organic fertilizer production and obtained biochars that met the Polish regulatory criteria for mineral-organic fertilizer.
Abstract: Sewage sludge (SS) recycling is an important part of the proposed 'circular economy' concept. SS can be valorized via torrefaction (also known as 'low-temperature pyrolysis' or 'roasting'). SS can, therefore, be considered a low-quality fuel or a source of nutrients essential for plant growth. Biochar produced by torrefaction of SS is a form of carbonized fuel or fertilizer. In this research, for the first time, we tested the feasibility of torrefaction of SS with high ash content for either fuel or organic fertilizer production. The research was conducted in 18 variants (six torrefaction temperatures between 200~300 °C, and three process residence times of 20, 40, 60 min) in 5 repetitions. Fuel and fertilizer properties and multiple regression analysis of produced biochar were conducted. The higher heating value (HHV) of raw SS was 21.2 MJ·kg-1. Produced biochar was characterized by HHV up to 12.85 MJ·kg-1 and lower H/C and O/C molar ratio. Therefore, torrefaction of SS with high ash content should not be considered as a method for improving the fuel properties. Instead, the production of fertilizer appears to be favorable. The torrefaction increased C, N, Mg, Ca, K, Na concentration in relation to raw SS. No significant (p < 0.05) influence of the increase of temperature and residence time on the increase of biogenic elements in biochar was found, however the highest biogenic element content, were found in biochar produced for 60 min, under the temperature ranging from 200 to 240 °C. Obtained biochars met the Polish regulatory criteria for mineral-organic fertilizer. Therefore SS torrefaction may be considered a feasible waste recycling technology. The calculation of torrefaction energy and the mass balance shows energy demand <2.5 GJ∙Mg-1 w.m., and the expected mass yield of the product, organic fertilizer, is ~178 kg∙Mg-1 w.m of SS. Further investigation should consider the scaling-up of the SS torrefaction process, with the application of other types of SSs.
17 citations
Cites background from "Utilization of sewage sludge in EU ..."
...The varied composition of SS from different sources and WWTPs processes implies a local, site-specific solution to the problem of SS disposal and utilization [2,3]....
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TL;DR: In this paper, a life cycle composite footprint index was proposed, including energy recovery, carbon emissions, water consumptions, nitrogen and sulfur flows, and a case study was carried out applying the established framework to assess six sludge-to-energy scenarios, covering dewatering, composting, drying, incineration, incinerated ash melting, and dewatered sludge melting.
17 citations
TL;DR: Lentil seeds treated with sludge ash based biofertilizer showed luxuriant growth with 19% enhanced root length, 42% in number of nodules, 10% in plant growth and 53.40% in seed yield as compared to conventional lignite formulations, indicating biofERTilizer produced from waste material sludgeAsh is not supposed to cause a hazard for the soil and plants when incorporated in defined amount.
17 citations
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TL;DR: In this paper, an analytical procedure involving sequential chemicai extractions was developed for the partitioning of particulate trace metals (Cd, Co, Cu, Ni, Pb, Zn, Fe, and Mn) into five fractions: exchangeable, bound to carbonates, binding to Fe-Mn oxides and bound to organic matter.
Abstract: An analytical procedure involving sequential chemicai extractions has been developed for the partitioning of particulate trace metals (Cd, Co, Cu, Ni, Pb, Zn, Fe, and Mn) into five fractions: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter, and residual. Experimental results obtained on replicate samples of fluvial bottom sediments demonstrate that the relative standard deviation of the sequential extraction procedure Is generally better than =10%. The accuracy, evaluated by comparing total trace metal concentrations with the sum of the five Individual fractions, proved to be satisfactory. Complementary measurements were performed on the Individual leachates, and on the residual sediments following each extraction, to evaluate the selectivity of the various reagents toward specific geochemical phases. An application of the proposed method to river sediments is described, and the resulting trace metal speciation is discussed.
10,518 citations
"Utilization of sewage sludge in EU ..." refers background in this paper
...Over the last decades, a great variety of extraction schemes, both simple and sequential have been developed and, although some methods have been widely used [12,13] none has been unreservedly accepted by the scientific community....
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Book•
01 Jan 1972
TL;DR: Wastewater Engineering: An Overview of Wastewater Engineering, Methods and Implementation Considerations as mentioned in this paper is a good starting point for a discussion of the issues of wastewater engineering. But, it is not a complete survey of the entire literature.
Abstract: Wastewater Engineering: An Overview. Wastewater Flowrates. Wastewater Characteristics. Wastewater Treatment Objective, Methods, and Implementation Considerations. Introduction to Wastewater Treatment Plant Design. Physical Unit Operations. Chemical Unit Processes. Biological Unit Processes. Design of Facilities for Physical and Chemical Treatment of Wastewater. Design of Facilities for the Biological Treatment of Wastewater. Advanced Wastewater Treatment. Design of Facilities for the Treatment and Disposal of Sludge. Natural-Treatment Systems. Small Wastewater Treatment Systems. Management of Wastewater from Combined Sewers. Wastewater Reclamation and Reuse.
3,826 citations
TL;DR: In this article, a review of the current and future issues related to the combustion of sewage sludge is presented, and a number of technologies for thermal processing of sludge are discussed in three groups, i.e., mono-combustion, cocombustions and alternative processes.
1,026 citations
"Utilization of sewage sludge in EU ..." refers background in this paper
...Multiple hearth and fluidized bed furnaces are the most popular and the latter is becoming widely applied [24]....
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...Analysis has shown that about 78–98% of Cd, Cr, Cu, Ni, Pb and Zn present in the sewage sludge are retained in the ash, whereas up to 98% of the Hg may be released into the atmosphere with the flue gas [24]....
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...The whole process is occurring in two distinctive regimes [24]:...
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TL;DR: In this article, the authors proposed a standardization with respect to grain size effects, commonly achieved by analyzing the sieve fraction <63μm, which is used to pin point major sources of metal pollution and to estimate the toxicity potential of dredged materials.
Abstract: Sediment analyses are used to pin‐point major sources of metal pollution and to estimate the toxicity potential of dredged materials on agricultural land. For source assessments (Part I of the present review) standardization is needed with respect to grain size effects, commonly achieved by analyzing the sieve fraction <63μm. Further aspects include sampling methods, evaluation of background data and extent of anthropogenic metal enrichment.
530 citations