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: It is argued that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions, and that the view on organic waste recycling needs to be diversified in order to improve the urban–rural nutrient cycle.
Abstract: The composition of municipal wastewater and sewage sludge reflects the use and proliferation of elements and contaminants within society. In Sweden, official statistics show that concentrations of toxic metals in municipal sewage sludge have steadily decreased, by up to 90 %, since the 1970s, due to environmental programmes and statutory limits on metals in sludge and soil. Results from long-term field experiments show that reduced metal pollution during repeated sewage sludge application has reversed negative trends in soil biology. Despite this Swedish success story, organic waste recycling from Swedish towns and cities to arable land is still limited to only about 20 % of the total amount produced. Resistance among industries and consumers to products grown on land treated with sewage sludge may not always be scientifically grounded; however, there are rational obstacles to application of sewage sludge to land based on its inherent properties rather than its content of pollutants. We argue that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions. The large volumes of sewage sludge collected in towns and cities are not equitably distributed back to arable land because of the following: (i) The high water and low nutrient content in sewage sludge make long-distance transportation too expensive; and (ii) the low plant availability of nutrients in sewage sludge results in small yield increases even after many years of repeated sludge addition. Therefore, nutrient extraction from urban wastes instead of direct organic waste recycling is a possible way forward. The trend for increased combustion of urban wastes will make ash a key waste type in future. Combustion not only concentrates the nutrients in the ash but also leads to metal enrichment; hence, direct application of the ash to land is most often not possible. However, inorganic fertiliser (e.g. mono-ammonium phosphate fertiliser, MAP) can be produced from metal-contaminated sewage sludge ash in a process whereby the metals are removed. We argue that the view on organic waste recycling needs to be diversified in order to improve the urban–rural nutrient cycle, since only recycling urban organic wastes directly is not a viable option to close the urban–rural nutrient cycle. Recovery and recycling of nutrients from organic wastes are a possible solution. When organic waste recycling is complemented by nutrient extraction, some nutrient loops within society can be closed, enabling more sustainable agricultural production in future.
150 citations
TL;DR: In this article, the authors compare the different approaches provided by European Member States for the reuse of biosolids in agricultural soils, focusing on the regulation of countries that reuse a significant amount of bio-solids for land application.
Abstract: The issues concerning the management of sewage sludge produced in wastewater treatment plants are becoming more important in Europe due to: (i) the modification of sludge quality (biological and chemical sludge are often mixed with negative impacts on sludge management, especially for land application); (ii) the evolution of legislation (landfill disposal is banned in many European countries); and (iii) the technologies for energy and material recovery from sludge not being fully applied in all European Member States. Furthermore, Directive 2018/851/EC introduced the waste hierarchy that involved a new strategy with the prevention in waste production and the minimization of landfill disposal. In this context, biological sewage sludge can be treated in order to produce more stabilized residues: the biosolids. In some European countries, the reuse of biosolids as soil improver/fertilizer in arable crops represents the most used option. In order to control the quality of biosolids used for land application, every Member State has issued a national regulation based on the European directive. The aim of this work is to compare the different approaches provided by European Member States for the reuse of biosolids in agricultural soils. A focus on the regulation of countries that reuse significant amount of biosolids for land application was performed. Finally, a detailed study on Italian legislation both at national and regional levels is reported.
149 citations
TL;DR: In this paper, the effectiveness of the carbons prepared in adsorption of Cu(II) has been studied as a function of pH, agitation time and temperature, and the results showed that the adaption was maximal at about pH 5.0.
148 citations
14 Oct 2015
TL;DR: This chapter elucidates the technologies of biological and chemical wastewater treatment processes and illustrates the wastewater treatment plants in terms of plant sizing, plant lay‐ out, plant design, and plant location.
Abstract: This chapter elucidates the technologies of biological and chemical wastewater treatment processes. The presented biological wastewater treatment processes include: (1) bioreme‐ diation of wastewater that includes aerobic treatment (oxidation ponds, aeration lagoons, aerobic bioreactors, activated sludge, percolating or trickling filters, biological filters, ro‐ tating biological contactors, biological removal of nutrients) and anaerobic treatment (anaerobic bioreactors, anaerobic lagoons); (2) phytoremediation of wastewater that in‐ cludes constructed wetlands, rhizofiltration, rhizodegradation, phytodegradation, phy‐ toaccumulation, phytotransformation, and hyperaccumulators; and (3) mycoremediation of wastewater. The discussed chemical wastewater treatment processes include chemical precipitation (coagulation, flocculation), ion exchange, neutralization, adsorption, and disinfection (chlorination/dechlorination, ozone, UV light). Additionally, this chapter elu‐ cidates and illustrates the wastewater treatment plants in terms of plant sizing, plant lay‐ out, plant design, and plant location.
142 citations
TL;DR: Understanding is provided of developing an effective approach for co-treating MSW and SS in the near future and the top four mid-point categories involving the largest effect on four cases are N-C (non-carcinogens), OLD (Ozone layer depletion), TET (Terrestrial eco-toxicity), and GWP (Global warming potential).
140 citations
References
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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