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: In this article, a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in Sao Paulo megacity is proposed.
Abstract: Currently, it is important to develop strategic frameworks to support the selection of sustainable resource recovery solutions. This study applies a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in Sao Paulo megacity. The framework comprises several steps based on case study-specific data and information from current literature. Data were collected from various sources: a survey with a wastewater treatment utility, national and regional databases, and review of local regulations and international literature. Treatment configuration, wastewater and by-products composition, potential demand (for water, energy, and phosphorus), stakeholder identification, and local legislation were thoroughly discussed regarding decision-making on resource recovery. Scenario analysis was used to explore suitable nutrient and energy recovery measures based on indicators. Biogas recovery and sewage sludge composting showed more favorable conditions due to similar experiences in the area and robust legislation. The proposed framework is a simplified tool, and its application can support managers to get information on resource recovery and how to plan such initiatives in easier ways to facilitate wiser decision-making, and better operation and management. The results on framework use and refinement can guide potential applications in other contexts and stimulate public policy formulation and further research.
16 citations
TL;DR: The bed density has an effect on the combustion efficiency of sludge, obtaining higher efficiencies in low- density beds for high temperature and air flow rates, while the efficiency was increased in high-density beds for low bed temperature and fluidizing air flow rate.
16 citations
TL;DR: In this paper, two plant growth trials were conducted in biosolid-treated iron mine soils and one (1) trial on undisturbed soil, under greenhouse conditions, for twelve (12) weeks.
Abstract: Past mining activities in Swaziland have left a legacy of abandoned mine sites (iron ore, asbestos, diamond and coal mine dumps), all of which have not been reclaimed. These sites were recently (2013) considered by the country’s wastewater treatment authorities as suitable places where biosolids can be applied, firstly as a biosolids disposal alternative and, secondly, as a strategy to accelerate mine soil remediation through phytostabilization. In order to understand the effects that this might have on mine soil conditions and microbiota, two (2) plant growth trials were conducted in biosolid-treated iron mine soils and one (1) trial on undisturbed soil, under greenhouse conditions, for twelve (12) weeks. According to the results obtained, the combination of biosolids and plants led to significant improvements (p < 0.05) in parameters related to soil fertility. Significant increases (p < 0.05) in alkaline phosphatase, β-glucosidase and urease soil enzyme activities were also observed. Copper and zinc were significantly (p < 0.05) increased (Cu from 17.00–50.13 mg kg−1; Zn from 7.59–96.03 mg kg−1); however, these sludge-derived metals did not affect enzyme activities. Improvements in soil physicochemical conditions, organic matter–metal complexes, effects of plants on metals and the essentiality of Cu and Zn to soil enzymes were thought to have masked the effects of metals. Increases in soil enzyme activities were considered to be indicative of improvements in the quality, fertility health and self-purification capacity of iron mine soils due to synergistic effects of biosolids and plants.
16 citations
11 Jun 2009
TL;DR: The feasibility of producing hydrogen-riched fuel gas from wet sewage sludge was assessed in this article, which consist in carrying out the pyrolysis of dewatered residual activated sludge as it is produced in the wastewater treatment plant with a moisture content of above 70%, without subjecting it to any previous thermal drying process.
Abstract: The feasibility of producing hydrogen-riched fuel gas from wet sewage sludge was assessed in this paper, which consist in carrying out the pyrolysis of dewatered residual activated sludge as it is produced in the wastewater treatment plant with a moisture content of above 70%, without subjecting it to any previous thermal drying process. In order to establish the most favorable conditions for the production of hydrogen-riched fuel gas, the effects of moisture content, heating rate and temperature were analyzed. It was found that the natural moisture of the sludge was converted into steam at high temperature, which can take part in the partial gasification of the sludge, leading to an increase in the gas production and the yield of hydrogen. In addition, pyrolyzing wet sludge at high temperature with high heating rates could maximize the gas yield productivity and raise its quality as a fuel and as a source of hydrogen or syngas as well. In this process, the drying, pyrolysis and gasification of wet sewage sludge were completed in a single thermal process, and resulting in a considerable amount of gases with potential value as fuels due to the relatively high calorific values they contain.
16 citations
TL;DR: In this paper, the authors compared various industrial waste products that can be used as cheap feedstock for the cultivation of single cell oil producing microorganisms, and compared their global availability, current use in competing industries, required pre-fermentation treatments, oleaginous microorganism cell concentrations and SCO yields.
Abstract: Abstract Single cell oil (SCO) is an attractive alternative source of oil, which, depending on the fatty acid composition, can be used as a feedstock for biodiesel production, as an ingredient for pharmaceuticals or as a source of essential fatty acids for human and animal consumption. However, the use of SCO is limited due to use of relatively expensive food or feed products in the cultivation of SCO producing microorganisms. In order to reduce SCO production costs, the use of cheaper feedstock such as biodegradable agro-industrial wastes are necessary. At the same time, the microbial treatment of biodegradable wastes ensures the neutralization of environmentally harmful compounds and reduces the negative impact on the environment. Oleaginous microorganisms are capable of fermenting a variety of industrial by-products, waste products and wastewaters, however further discussion on properties of the waste materials is necessary to facilitate the selection of the most appropriate waste materials for SCO production. Thus, this review compares various industrial waste products that can be used as cheap feedstock for the cultivation of SCO producing microorganisms. Industrial waste products, by-products and wastewaters are compared according to their global availability, current use in competing industries, required pre-fermentation treatments, oleaginous microorganism cell concentrations and SCO yields.
16 citations
Cites background from "Utilization of sewage sludge in EU ..."
...alone about 33 million tonnes of sewage sludge are generated annually [51]–[54]....
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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