Recycling and recovery routes for incinerated sewage sludge ash (ISSA): a review.
TL;DR: The authors in this article reviewed the drivers for increasing incineration of sewage sludge and the characteristics of the resulting incinerated sludge ash (ISSA) and concluded that ISSA has significant potential to be used as a secondary source of phosphate for the production of fertilisers and phosphoric acid.
About: This article is published in Waste Management.The article was published on 2013-11-01. It has received 393 citations till now. The article focuses on the topics: Sludge.
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TL;DR: In this article, an assessment of the leading disposal (volume reduction) and energy recovery routes such as anaerobic digestion, incineration, pyrolysis, gasification and enhanced digestion using microbial fuel cell along with their comparative evaluation, to measure their suitability for different sludge compositions and resources availability.
463 citations
Cites background from "Recycling and recovery routes for i..."
...The P-recovery from WAS incineration ashes is also under investigation nowadays [177-180]....
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TL;DR: This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovered P, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water.
Abstract: Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.
435 citations
TL;DR: In this article, the options of converting sewage sludge to energy and fuel via three main thermochemical conversion processes namely pyrolysis, gasification and combustion are reviewed, and various alternative approaches deserving further consideration, such as the incorporation of pre-processing and co-utilization, are discussed.
Abstract: Sewage sludge, the inevitable by-product of municipal wastewater treatment plant operation, is a key issue in many countries due to its increasing volume and the impacts associated with its disposal. Thermochemical processing offers a new way of managing sewage sludge, not only by providing effective volume reduction, but also enabling transformation of carbon-rich organic fraction into valuable energy and fuel. Owing to some unique properties, sewage sludge differs from other solid fuels such as lignocellulosic biomass and coal, making its thermochemical conversion application somewhat complicated and challenging. This paper reviews the options of converting sewage sludge to energy and fuel via three main thermochemical conversion processes namely pyrolysis, gasification and combustion. The fundamental aspects of sewage sludge and its behaviour in each of thermochemical process are summarised. The challenges in adopting thermochemical conversion technology in sewage sludge management are addressed, and various alternative approaches deserving further consideration, such as the incorporation of pre-processing and co-utilisation, are discussed.
411 citations
TL;DR: In this article, the most popular methods of sewage sludge management and associated unit operations and processes referring to them are presented, such as: reclamation and adaptation of lands to specific needs; plant cultivation not intended for consumption or for production of food; usage in agriculture, usage in building; recovery of phosphorus, rare earth metals or fats and usage in industry; producing combustible pellets, granulates or other usable materials such as absorbents; and storage on territory of treatment plant and landfills.
402 citations
TL;DR: It is suggested that the current poor understanding of iron and phosphorus chemistry in wastewater systems is preventing processes being developed to recover phosphorus from iron-phosphorus rich wastes like municipal wastewater sludge.
Abstract: The addition of iron is a convenient way for removing phosphorus from wastewater, but this is often considered to limit phosphorus recovery. Struvite precipitation is currently used to recover phosphorus, and this approach has attracted much interest. However, it requires the use of enhanced biological phosphorus removal (EBPR). EBPR is not yet widely applied and the recovery potential is low. Other phosphorus recovery methods, including sludge application to agricultural land or recovering phosphorus from sludge ash, also have limitations. Energy-producing wastewater treatment plants increasingly rely on phosphorus removal using iron, but the problem (as in current processes) is the subsequent recovery of phosphorus from the iron. In contrast, phosphorus is efficiently mobilized from iron by natural processes in sediments and soils. Iron–phosphorus chemistry is diverse, and many parameters influence the binding and release of phosphorus, including redox conditions, pH, presence of organic substances, and...
365 citations
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TL;DR: In this article, the authors put forward the case for including long-term phosphorus scarcity on the priority agenda for global food security, and presented opportunities for recovering phosphorus and reducing demand together with institutional challenges.
Abstract: Food production requires application of fertilizers containing phosphorus, nitrogen and potassium on agricultural fields in order to sustain crop yields. However modern agriculture is dependent on phosphorus derived from phosphate rock, which is a non-renewable resource and current global reserves may be depleted in 50–100 years. While phosphorus demand is projected to increase, the expected global peak in phosphorus production is predicted to occur around 2030. The exact timing of peak phosphorus production might be disputed, however it is widely acknowledged within the fertilizer industry that the quality of remaining phosphate rock is decreasing and production costs are increasing. Yet future access to phosphorus receives little or no international attention. This paper puts forward the case for including long-term phosphorus scarcity on the priority agenda for global food security. Opportunities for recovering phosphorus and reducing demand are also addressed together with institutional challenges.
4,220 citations
"Recycling and recovery routes for i..." refers background in this paper
...At current rates of consumption, it is estimated that only 50–100 years of economically viable phosphate reserves remain (Cordell et al., 2009; Franz, 2008; Steen, 1998)....
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...Phosphate prices have increased considerably since then and there is added environmental awareness amongst governments and companies which is a significant driver for phosphate recovery (Cordell et al., 2009; Driver et al., 1999; Levlin et al., 2002; Schipper et al., 2001)....
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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.
1,242 citations
"Recycling and recovery routes for i..." refers methods in this paper
...For an excellent review of thermal treatment options of sewage sludge the reader is directed to work by Werther and Ogada (1999) and Fytili and Zabaniotou (2008)....
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TL;DR: In this article, the global mobilization of the element, a part of the grand geotectonic denudation-uplift cycle, is slow and low solubility of phosphates and their rapid transformation to insoluble forms make the element commonly the growth-limiting nutrient, particularly in aquatic ecosystems.
Abstract: ▪ Abstract Phosphorus has a number of indispensable biochemical roles, but it does not have a rapid global cycle akin to the circulations of C or N. Natural mobilization of the element, a part of the grand geotectonic denudation-uplift cycle, is slow, and low solubility of phosphates and their rapid transformation to insoluble forms make the element commonly the growth-limiting nutrient, particularly in aquatic ecosystems. Human activities have intensified releases of P. By the year 2000 the global mobilization of the nutrient has roughly tripled compared to its natural flows: Increased soil erosion and runoff from fields, recycling of crop residues and manures, discharges of urban and industrial wastes, and above all, applications of inorganic fertilizers (15 million tonnes P/year) are the major causes of this increase. Global food production is now highly dependent on the continuing use of phosphates, which account for 50–60% of all P supply; although crops use the nutrient with relatively high efficien...
1,122 citations
Additional excerpts
...(Smil, 2000; C.E.E....
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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
"Recycling and recovery routes for i..." refers background or methods in this paper
...These issues also apply to ISSA despite the fact that mono-combustion of sewage sludge has been widely practised at an industrial scale in many dedicated plants across the world over several decades (Werther and Ogada, 1999)....
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...For an excellent review of thermal treatment options of sewage sludge the reader is directed to work by Werther and Ogada (1999) and Fytili and Zabaniotou (2008)....
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TL;DR: The formation, control and recovery of struvite from primarily municipal wastewater and other waste streams are reviewed and treatment options for control and technologies for recovery are discussed.
832 citations
"Recycling and recovery routes for i..." refers background in this paper
...One well known example of phosphate recovery from sewage is controlled struvite precipitation but this is a complex process dependent on many factors such as pH, Mg2+ and NH4+ concentrations (Doyle and Parsons, 2002)....
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