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The functioning of societies involves the generation of large amounts of municipal waste. This study analyses the amounts of pollutants emitted during waste incineration at selected waste incineration plants in 2022. Four plants were analyzed, including three with the highest waste processing efficiency (Copenhagen, Poznan and Kraków) and one with the lowest efficiency (Konin). The choice of the factory in Copenhagen was also dictated by its strategic location in the city center. Analysing the emissions from the selected plants it can be concluded that environmental safety was maintained and none of the plants exceeded the permissible emissions value. [ABSTRACT FROM AUTHOR]

The trend in the development of railway transport also includes the solution of such an important environmental, technological, sanitary and, to some extent, aesthetic problem as the transfer of all operated mainline passenger trains to environmentally friendly toilet complexes (EFTC). For the disposal of EFTC waste, a system has been created for the disposal of fecal waste in parking lots, which are then transported by sewage disposal machines and dumped into general treatment facilities. At the moment, as one of the possible options for industrial waste disposal of EFTC, wastewater sludge incineration plants are being considered. The method of waste incineration reduces the time, labor and financial costs of waste turnover, and taking into account the epidemiological risks of fecal waste, it has high development prospects. This article discusses similar combustion processes using the example of technologies implemented at wastewater sludge incineration plants, emissions from enterprises and the processes of formation of pollutants. And also, within the framework of this work, a comparative analysis of the control of emissions of pollutants from the combustion of sewage sludge into the atmosphere in the Russian Federation and in the EU, countries were carried out.

Nowadays, increasing attention is focused on the indirect impacts of emission control technologies and the potential burden shifting. A clear example is the generation of wastewater when wet scrubbing systems are used for flue gas cleaning. The present study takes into consideration a typical wet scrubber for waste-to-energy plants and the available options for wastewater management: physicochemical treatment, evaporation or valorisation. A comparative assessment of the environmental footprint of the alternatives is performed by taking into account the burdens related to the supply of reactants, energy and the disposal of process residues (solid and liquid waste streams). It is thus shown that the recovery of a marketable product from the effluent produces a net environmental benefit, while the choice between wastewater discharge or evaporation represents only a shift of burden between the water and the soil compartments. [ABSTRACT FROM AUTHOR]

Wet chemical approach is widely applied for P extraction from incinerated sewage sludge ash (ISSA) due to the relatively simple process and low lost. In this study, H 2 SO 4 and H 2 C 2 O 4 were compared to recover P from ISSA through three steps of acid leaching, cation exchange resin (CER) purification and precipitation. Transformations of P speciation and mineral phases in ISSA from 600 to 900 °C were studied. The results showed that the ISSA samples were mainly composed of inorganic P (IP), and part of non-apatite IP (NAIP, mainly AlPO 4) would transform to apatite P (AP, Ca 3 (PO 4) 2) with the increase in temperature. The ratio of NAIP to IP dropped from 71.9% at 600 °C to 53.7% at 900 °C. Effect of acid concentration on the leaching efficiency of P from the ISSA samples incinerated at different temperatures by H 2 SO 4 and H 2 C 2 O 4 was investigated, and the leaching behaviors of key elements of P, Ca, Al and Fe were compared. H 2 C 2 O 4 exhibited a better performance than H 2 SO 4 for the leaching efficiency of P. Severe sintering of ash particles occurred at temperature >800 °C inhibited the P leaching by H 2 SO 4. During CER purification, the impurity elements in the H 2 SO 4 leachate were easily removed by CER, whereas the Al and Fe elements in the H 2 C 2 O 4 leachate were hardly removed due to the formation of anionic complexes between Al3+/Fe3+ and oxalic ions. Finally, high-purity struvite product was synthesized from the purified H 2 SO 4 leachate, which could be directly utilized as a fertilizer with negligible environmental risk. Amorphous aluminum and iron hydroxyphosphates were obtained from the H 2 C 2 O 4 leachate. This study provides insights for P recovery from ISSA samples by different acid leaching systems. Image 1 • H 2 SO 4 and H 2 C 2 O 4 were used for leaching and recovering P from ISSA comparatively. • Transformation of P speciation and mineral phases in ISSA at 600–900 °C was studied. • Leaching behaviors of ISSA incinerated at different temperatures were investigated. • Migration of key elements of P, Ca, Al and Fe in the recovery process was presented. • P recovery product from H 2 C 2 O 4 leachate of ISSA was first studied. [ABSTRACT FROM AUTHOR]

A substantial amount of ash is produced after the incineration of sewage sludge which is difficult to manage. Its potential use as a cost-effective adsorbent for heavy metals is beneficial to both waste management and wastewater treatment. In this study, the adsorption kinetics, isotherms as well as the factors influencing the adsorption performance were assessed through batch sorption experiments. The results show that incinerated sewage sludge ash (ISSA) was effective in adsorbing Pb(II) from aqueous solution in a wide pH range (3.00–6.00) due to the combined contributions of ion exchange, precipitation and complexation, which was confirmed by systematic investigation through XRD, SEM-EDX, FTIR, XPS and a sequential extraction procedure (SEP) for Pb(II). Nonetheless, the adsorption of Pb(II) by ISSA would be adversely affected by high ionic strength. The sorption process was fast, and the equilibrium data could be well described by the Langmuir model, the maximum uptake capacity for Pb(II) increased with temperature and the calculated adsorption capacities at 298, 308 and 318 K for Pb(II) were 58.28, 60.06 and 62.42 mg/g, respectively. These findings indicate the ISSA can be recognized as a high-performance adsorbent for Pb(II) removal in wastewater treatment applications. Image 1 • The first utilization of ISSA as a high-performance adsorbent for Pb(II) removal was investigated. • ISSA can remove lead effectively at a wide initial pH range from 3.00 to 6.00. • An adsorption capacity of 62.42 mg/g was achieved at 318 K. • The adsorption mechanisms were elucidated. • The environmental risk of the ISSA after adsorption was evaluated. [ABSTRACT FROM AUTHOR]

Currently, there is little doubt that the global temperature increase is a consequence of the concentrations of manmade greenhouse gases. Sustainable alternatives such as the use of supplementary cementitious materials and the reduction of sanitary landfills through the incineration of sewage sludge hold promise for the reduction of these gases. An experimental design is proposed to make the incineration of sewage sludge (SS) more efficient, thereby improving the sewage slush ash (SSA) produced as a supplementary cementitious material. Different maximum temperatures and residence times were studied in the partial replacement of Portland and blended cements; the resulting SSAs contributed to the mechanical behavior of concrete through improved hydraulic and pozzolanic activity in addition to intense interactions with cement. The particle size distributions of the SSAs were similar to those of the cements, but the specific surface areas of the SSAs were up to 18 times higher than those of the cements. This vast difference is explained by the presence of micropores after the incineration process. Consequently, the specific surface area of the SSA particles was the most important property explaining the pozzolanic activity and interaction effects with cement. Lower incineration temperatures and higher incineration times increased the specific surface area, therefore increasing the cementitious performance of SSA. The SSA cementitious performance was lower in blended cement than in Portland cement; however, the replacement of blended cement by SSA increased the compressive strength at early and late ages. • Incineration treatment is relevant to the cementitious performance of sewage sludge ashes (SSA). • The replacement of blended cement by SSA increased the compressive strength at early and late ages. • The SSA cementitious performance was lower in blended cement than Portland cement. • The SSA specific surface was the most important property explaining the pozzolanic capacity and interaction with cement. • The temperature-time interaction during incineration influences the particle size and specific surface of the SSAs. [ABSTRACT FROM AUTHOR]

Abstract The recycling and reuse of phosphorus from incineration fly ash of sewage sludge are considered to be feasible and economical. Addition of biomass was proposed to increase the plant availability of phosphorus from the fly ash during industrial sewage sludge (ISS) incineration. Co-combustion experiments of ISS and four types of biomass were performed in a laboratory-scale bubbling fluidized bed. The experimental results reveal that the mass percentage of phosphorus present in fly ash increases by addition of biomass into ISS during incineration. During ISS incineration alone, phosphorus in the fly ash is mainly present in the form of apatite phosphorus (AP), exhibiting high bioavailability. After co-firing of ISS with biomass, the Ca, Cl, and Mg compounds in biomass effectively facilitate the speciation conversion of non-apatite inorganic phosphorus (NAIP) like AlPO 4 to new AP, such as Ca 2 P 2 O 7 , Ca 5 (PO 4) 3 Cl, and Ca 4 Mg 5 (PO 4) 6. Compared with wood, wheat straw, and corn stalk, the effect of cotton stalk is better. It is also found that increasing the cotton stalk mass ratio in mixture favors the transformation of NAIP to AP. The phosphorus solubility of the co-firing fly ash in citric acid (2%) increases to 83.30% with increasing the cotton stalk ratio to 50%, improving the phosphorus bioavailability. Highlights • P mass fraction distributed in fly ash increases after co-firing of ISS with biomass. • P in the fly ash from ISS incineration alone is mainly present in the form of AP. • Ca, Cl, and Mg compounds in biomass promote the conversion of NAIP to AP in fly ash. • Effect of addition of cotton stalk on P bioavailability in fly ash is obvious. • P solubility of the co-firing fly ash in 2% citric acid reaches up to 83.30%. [ABSTRACT FROM AUTHOR]

• 0.73–1.03 g N-NH 3 kg−1 TS of sewage sludge was released to off-gases under 160 °C. • The mass released corresponds to 41–58% of ionized nitrogen content in raw sludge. • The global warming potential of the recovery process is 4.1 kg CO 2 -Equiv. kg−1 N. Thermal drying and consequent incineration of sewage sludge result in an absolute loss of an important macronutrient – nitrogen. To fulfill the growing food demand, humanity relies more on industrial fixation of nitrogen, primarily via the Haber-Bosch process. The present paper examines the nitrogen release during continuous thermal drying of municipal sewage sludge and its consequent recovery for fertilization. Furthermore, the possibility of nitrogen recovery from condensate is assessed. Finally, the study assesses the global warming potential of the proposed nitrogen recovery system and compares it with the baseline system manufacturing fertilizers from industrially fixed nitrogen. The results of the drying experiments showed that 0.73–1.03 g N-NH 3 kg−1 total solids of sewage sludge was released to off-gases during its continuous thermal drying under 160 °C, which corresponds to 41–58% of ionized nitrogen content in raw sewage sludge subjected to thermal drying. The global warming potential of the nitrogen recovery was 28% lower compared to that of the commercial fertilizer production of equivalent properties: 4.1 kg CO 2 -Equiv. kg−1 N versus 5.7 kg CO 2 -Equiv. kg−1 N. Still, the sensitivity analysis showed that the results might traverse and lead to a higher global warming potential of 6.2 kg CO 2 -Equiv. during the nitrogen recovery process under certain process parameters. [ABSTRACT FROM AUTHOR]

• Valorization of SMS and ash into the substrate for agriculture was proposed. • The solid-state solubilization of phosphorus was conducted. • SMS was used as a source of nutrients for A. Frrooxidans. • Phosphorus from ash was released in the available to plants form. This work describes the possibility of utilization of ash originated from the incineration of sewage sludge from the wastewater treatment plant with the 3rd stage of biological treatment, and spent mushrooms substrate (SMS) as a raw material for the production of the substrate for agriculture and horticulture with the property of slow-releasing of phosphorus via solubilization process. Ash was mixed with SMS in different ratios (1, 5 and 10%), where SMS was used as a substrate/medium – the source of nutrients necessary for the growth of bacteria Acidithiobacillus ferrooxidans (A. ferrooxidans) , while the ash was used as a source of phosphorus. Solubilization of phosphorus from ash via solubilization process was conducted for 50 days. During this time pH, conductivity, as well as the concentration of available forms of phosphorus were monitored. Obtained results were compared with the control group deprive inoculation by A. ferrooxidans. The concentration of available to plants phosphorus (express as P 2 O 5) was an average 1.5 times higher in the SMS inoculated with A. ferrooxidans in all considered groups. Observation confirms the possibility of utilization of treated SMS as a substrate in agriculture and horticulture as the utilitarian properties (weight and length of plant/root) of plants obtained in germination test were higher when compared with the control group where SMS without inoculation was used. [ABSTRACT FROM AUTHOR]

Highlights • Rectification residue and raw meal were co-incineration in a tube furnace. • Influence of the co-processing conditions on chlorine evolution was studied. • Chlorine mainly existed in flue gas and residual solid. • Temperature and retention time had an important effect on the distribution of Cl. Abstract The co-processing of hazardous waste in cement kiln can eliminate a large number of hazardous wastes, but the excessive existence of chlorine will affect normal operation of cement kiln. In this study, the partition of Cl in flue gas, fly ash and residual solid under different experiment conditions was obtained by using tubular furnace to incinerate mixtures of rectification residue and raw meal. The chlorine content in flue gas was determined using ion chromatography and the chlorine content in fly ash and residual solid was measured by high temperature combustion hydrolyzing-ion chromatography. The results showed that chlorine mainly existed in flue gas and residual solid, and only less than 3.5% of chlorine existed in fly ash. The incineration temperature had a significant effect on the distribution of chlorine in each part. The higher the incinerating temperature, the greater the proportion of chlorine in flue gas and fly ash. While temperatures were higher than 1300 °C, the proportion of chlorine in all parts remained basically unchanged, roughly 18:14:1. With the increase of the retention time, the proportion of chlorine in the residual solid decreased gradually, and the proportion of chlorine in the flue gas increased gradually. The distribution ratio of chlorine in each part remained unchanged after about 30 min. In addition, the chlorine content of the sample and the air flow rate had a relatively slight effect on the partition of chlorine. Based on these experimental results, some suggestions on the co-processing of hazardous waste in cement kiln were put forward. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Heavy metal amounts and leaching in China were compared to those on a global scale. • The RAC index corresponding to heavy metal leaching concerned with FA compositions. • Alkalinity and S-Cl contributed to the heavy metal leaching potential in statistics. • A new leaching index (Φ) was defined according to the compositional variety in FA. • The quick prediction of Pb and Cd stability from FA was achieved via the index Φ. Abstract In the current work, a quick prediction of the heavy metal (HM) leaching potential in municipal solid waste incineration fly ash (MSWI FA) was developed based on the statistical data between the HM leaching behaviors and the compositional variety in FA from China. In the comparison of the surveyed (508 data points) leaching concentrations, Pb and Cd leaching amounts in FA exceeded the Toxicity Characteristic Leaching Procedure (TCLP) limits most frequently. Moreover, the chemical compositions (pH and soluble chlorine (S-Cl)) of FA were proposed to have significant linear correlations with the Pb and Cd leaching. This corresponded to the chemical fraction change of the HM (risk assessment code (RAC)), which was relative to the pH of FA and chloride. This suggests that the HM stability can be evaluated by these factors. To verify this hypothesis, principal component analysis (PCA) and multiple linear regressions were used to evaluate the relationship between 5 indices and the leaching concentrations of Pb and Cd in 160 MSWI FA samples after stabilization/solidification from eastern China. It is indicated that pH, S-Cl and free CaO were the critical variables in Pb and Cd leaching. Accordingly, a new index, Φ, combined with the logistic model was proposed to predict the leaching potential. It is revealed that the high risk of the exceeding the limits for HM leaching occurred when Φ was below 12.5. Our results assess the HM stability in MSWI FA with its compositional variety in a statistical way, which gives an approach for the quick prediction of HM leaching potential. [ABSTRACT FROM AUTHOR]

Highlights • Efficiency in hazardous waste management in European countries. • Performance assessment of European countries, using data envelopment analysis (DEA). • Use of novel input/output environmental parameters. Abstract The study of efficiency in hazardous waste management has been proved to be a driving factor for sustainable development (SD). This study focuses on a performance assessment of European countries, most of them European Union (EU) member states and candidate countries that share a common legislative framework through European regulations, in order to provide a general understanding of hazardous waste performance. In this paper, we use Data Envelopment Analysis (DEA) to examine the efficiency of 32 countries in Europe by using novel input/output environmental parameters to study the efficiency of the different waste management operations from an environmental point of view. This analysis contrasts the efficiency in the management of total waste versus hazardous waste and studies three operations with hazardous wastes: incineration and incineration with energy recovery, disposal and recovery. Results show that there are differences in the achievement of efficiency, not only among countries, but also among the different waste management operations analysed. [ABSTRACT FROM AUTHOR]

Biological treatment is not completely effective for the removal of all refractory organics, including fulvic-like and humic-like substances, in fresh leachate from municipal solid waste (MSW) incineration. In this study, a UV/peroxymonosulfate (PMS) process was used to degrade the refractory pollutants that remained in the bio-treatment effluent. The reaction conditions were optimal when 10 g/L of PMS was used at a pH of 8.96. 70.6% of COD was degraded within 60 min with optimal reaction conditions. The refractory organics were degraded by the UV/PMS process, which generated intermediates with low molecular weight. The mechanisms involved in this advanced degradation process were uncovered by detecting the generation and conversion of radicals during the oxidation reaction. [ABSTRACT FROM AUTHOR]

The latest European Union legislation introduced the possibility of considering high efficiency incineration of waste as a recovery operation, that is, to use waste as a means of producing energy and hence able to replace other fuels. This possibility has been further investigated by expanding the boundaries for the mass and energy balance of municipal solid waste incinerators operating in the EU28. An energetic analysis based on a hybrid primary energy (MJ Mg-1) approach was performed also using the cumulative energy demand index. Average results showed a net hybrid primary energy >0 for those municipal solid waste incinerators recovering only electricity, indicating that no primary energies can be replaced. For those operating in combined heat and power mode, an average hybrid primary energy ranging from about −200 MJ Mg-1 to about −4800 MJ Mg-1 was detected for large-size municipal solid waste incineration facilities (>200,000 Mg y-1). The value of hybrid primary energy for medium and small facilities ranged from about +3000 MJ Mg-1 to −4000 MJ Mg-1. Furthermore, in some operating conditions landfill had a lower hybrid primary energy than those of small-size municipal solid waste incinerators. To some degree, these results are not in agreement with the classification of municipal solid waste incinerators based on the energy efficiency formula, particularly for those recovering only electrical energy. [ABSTRACT FROM AUTHOR]

Highlights • Processed MSWI residues were characterized, which has been seldom studied. • The environmental risks of different size fractions of the waste were evaluated. • Studied MSWI residues can serve as urban mines of precious metals (high Pt, Au) Abstract As conventional end-of-life disposal, municipal solid waste (MSW) incineration residues can be problematic due to potential release of toxic compounds into the environment. Using municipal solid waste incineration residues as urban-mine of valuable metals (e.g. precious metals) could provide a trash-to-treasure possibility. The objectives of the study are to (i) determine the contents of different contaminant metallic elements (Zn, Cu, Ba, Pb, Cr and Ni) in four size fractions of MSW incineration residues and discuss their mobility potential by using the modified BCR sequential extraction method; (ii) investigate the level of valuable critical contents (precious metals, rare earth elements, etc.) in these wastes. We also characterized mineralogy and elemental composition of four different grain size fractions (0–0.5, 0.5–2.0, 2.0–4.0 and 4.0–16.0 mm) of processed municipal solid waste incineration residue (PIR) from the Southwestern region of Germany, using X-ray fluorescence, X-ray powder diffraction and different spectroscopic techniques. Among all studied size fractions, grains smaller than 2 mm contained higher amounts of total extractable heavy metals in most cases. The most important finding of the study is that the total contents of Cu, Au and Pt in the incineration residues reached economically profitable levels (5.1 g/kg, 21.69 mg/kg and 17.45 mg/kg, respectively). [ABSTRACT FROM AUTHOR]

Sites of accumulated ecological damage (AED) should be ranked according to the extent of their danger to the environment. Key sites of AED are sewage dumps. The different compositions of pollutants in the sewage deposits create a threat to the geoecological balance and the hygiene of the population. Results are given in this article for a study of the parasite microflora in the surface layer of soils of a sewage deposit dump. The content of the parasite microflora exceeding normal levels was examined. [ABSTRACT FROM AUTHOR]

Using sludge incineration residue (SIR) to prepare SIR-based geopolymer can realize the minimization and reclamation of urban sludge as well as the stabilization of potential toxic elements. This work has researched the critical factors that influence the formulation of SIR-based geopolymer and the stabilization performance on potential toxic elements. Results showed that the addition amount of SIR had significant influence on the compressive strength of geopolymer, while the modules of sodium silicate and the sodium silicate/metakaolin ratio had little influence thereon. When the addition amount of SIR was 10%, the modules of sodium silicate was 1.3 and the sodium silicate/metakaolin ratio was 0.86, the compressive strength of geopolymer reached the maximum of 95.6 MPa. When the temperature increased from 25 °C to 800 °C, the compressive strength showed a tendency of increasing first and then decreasing. SIR-based geopolymer could significantly reduce the leaching of Zn and Cu from 1264.8 mg/kg and 856.3 mg/kg to 50.8 mg/kg and 30.7 mg/kg respectively, leading to a stabilizing efficiency more than 96%. pH influenced the stabilization of geopolymer on the potential toxic elements, the effective diffusion coefficients De of Zn, Cu, Ni, Pb and Cr at pH = 4 were higher than those at the pH of 7, which were probably due to the physic-chemical characteristics and the corresponding changes in the leaching and species distribution of the potential toxic elements. [ABSTRACT FROM AUTHOR]

Controlling the removal of heavy metals such as Copper (Cu), Zinc (Zn), lead (Pb) and cadmium (Cd) during the sewage sludge incineration and the recovery of phosphorus (P) from sewage sludge ash (SSA) remain challenging. Herein we aim to investigate the effect of the temperature, retention time and chlorinating agent additives (MgCl 2 and KCl) on both the behavior of selected heavy metals and the fixed rate of phosphorus (P) during sewage sludge incineration. Dry sewage sludge was mixed with various amounts of chlorinating agent and treated by a laboratory scale furnace in the temperature range of 800–1000 °C for different retention times (30, 60 and 120 min). The results demonstrated that the removal efficiency of heavy metals exhibited an increasing tendency with the addition of chloride, especially in the cases of Cu, Zn and Pb. Moreover, the temperature and retention time demonstrated significant effects on the promotion of heavy metals removal. In the case of Pb 96% was removed at 800 °C within 120 min, while 86.6% of Cd was effectively removed at 1000 °C within 30 min. MgCl 2 proved to be more effective than KCl in improving the removal efficiency of heavy metals, such that up to 81.6% of Cu, 84.9% of Pb and 73.5% of Zn was removed with the addition of 15%wt Cl − /sewage sludge (SS(, At 960 °C, the boiling point of cadmium chloride CdCl 2 and CdO.Al 2 O 3 .2SiO 2 retention time and chlorinating agent had no impact on Cd removal. It was also observed that high temperature was beneficial for the transformation of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP). At 900 °C this transformation is efficient for Phosphate fixation, which is evidence that apatite phosphorus (AP) has the ability to be more stable than non-apatite inorganic phosphorus (NAIP) at high temperature. [ABSTRACT FROM AUTHOR]

Waste solvents generated by the process industry are frequently incinerated as a part of their treatment, thus allowing for a partial recovery of their combustion heat. While large chemical sites often have in-house waste incineration facilities, smaller enterprises have to outsource the treatment of their residuals, leading to significant shipments of hazardous substances. In this sense, there is a significant optimization potential to reduce both shipments and the consumption of auxiliary fuels, thus leading to an overall reduction of the primary energy required to produce and deliver chemical products and intermediates. However, inconsistent data systems and incomplete information represent main barriers for investigating the potential of such environmental benefits. As information about waste properties does not need to be reported, it is consequently not possible to rigorously estimate the energetic potential of the hazardous waste produced in a specific area, which would be a crucial first step in the optimization of both design and management of a supply chain network of industrial waste. This work proposes a novel approach for the estimation of hazardous waste properties, combining existing information stemming from industrial and institutional partners. Such framework creates a new waste classification system based on water and pollutant content that links inconsistent data sources with different degrees of detail, and allows for estimating average properties, including the energy content, of different types of primary produced hazardous liquid waste. The validity of the developed methodology for a broad application range is tested with a case study about Switzerland, which, because of its sparse chemical and pharmaceutical industry and an extreme variety in terms of generated waste residues, represents one of the most challenging cases. Such case study investigates the evolution of Swiss industrial waste from 2010 to 2014, determines average properties for 12 different waste classes and their total energy recovery potential. [ABSTRACT FROM AUTHOR]

Significant knowledge and data gaps associated with the fate of product-embedded engineered nanomaterials (ENMs) in waste management processes exist that limit our current ability to develop appropriate end-of-life management strategies. This review paper was developed as part of the activities of the IWWG ENMs in Waste Task Group. The specific objectives of this review paper are to assess the current knowledge associated with the fate of ENMs in commonly used waste management processes, including key processes and mechanisms associated with ENM fate and transport in each waste management process, and to use that information to identify the data gaps and research needs in this area. Literature associated with the fate of ENMs in wastes was reviewed and summarized. Overall, results from this literature review indicate a need for continued research in this area. No work has been conducted to quantify ENMs present in discarded materials and an understanding of ENM release from consumer products under conditions representative of those found in relevant waste management process is needed. Results also indicate that significant knowledge gaps associated with ENM behaviour exist for each waste management process investigated. There is a need for additional research investigating the fate of different types of ENMs at larger concentration ranges with different surface chemistries. Understanding how changes in treatment process operation may influence ENM fate is also needed. A series of specific research questions associated with the fate of ENMs during the management of ENM-containing wastes have been identified and used to direct future research in this area. [ABSTRACT FROM AUTHOR]

In this paper, the thermal characteristics of sewage sludge and the transformation behavior of Pb and Cd during the thermal conversion process were addressed. The incineration process and pyrolysis process of the sewage sludge were investigated by thermogravimetric analysis. The results indicated that the thermal conversion process of the sewage sludge could be divided into three stages and the presence of oxygen could accelerate the decomposition of the sewage sludge. Furthermore, the effects of thermal conditions on the concentration ratio of Cd and Pb and their species partitioning in the residual char and ash were investigated. For the pyrolysis process, the maximum concentration ratio of Cd reached 41.64% at 500 °C and the lowest one 2.92% at 700 °C. Contrary, the concentration ratio of Pb remained above 93% as the temperature increased. Thus, the suitable temperature for the sewage sludge pyrolysis was below 500 °C. For the incineration process, the incineration temperature had great influence on the concentration ratio of Cd and Pb. When the incineration temperature increased from 700 °C to 900 °C, the concentration ratio of Cd decreased drastically from 99.32% to 10.96%. The maximum concentration ratio for Pb (95.31%) was reached at 800 °C. Besides, the lowest concentration ratio of Cd and Pb were obtained at a residence time of 30 min. The partitioning analyses of the Cd and Pb contained in the ash showed that the residence time had little effect on the partitioning of Cd and Pb, and the residual fractions of Cd and Pb were both above 90%. It was concluded that Cd and Pb were properly stabilized in the ash. Thus, Cd and Pb in the ash were difficult to be released into the environment and to cause secondary pollution. [ABSTRACT FROM AUTHOR]

The potential of six different extractants to recover phosphorus (P) from incinerated sewage sludge ash (ISSA) was evaluated. Secondary effects such as the co-dissolution of Zn and Cu were also considered. The residual ISSA from each study was assessed in particular detail, focusing on the leachability of remaining Zn and Cu, major element composition, crystalline phases and overall degree of crystallinity and particle size distribution. The residual ISSA was also evaluated as a pozzolanic material using a Strength Activity Index (SAI) test with mortars containing Portland cement with a 20% substitution by ISSA. All results were compared to tests with untreated ISSA. Overall, the use of 3 of the 6 extractants could be ruled out due to poor P recovery potential and/or a serious compromise of the potential reuse of residual ISSA in Portland cement-based materials. The results highlight the added value of considering the potential reuse of residual ISSA when trying to optimize P recovery from ISSA by wet methods. [ABSTRACT FROM AUTHOR]

This article describes a pilot test at a sewage sludge incineration plant and shows its results considering the impacts of reducing the minimum combustion temperature from 850°C to 800°C. The lowering leads to an actual reduction of the average combustion temperature by 25 K and a significant reduction in the fuel oil consumption for support firing. The test shall be used for providing evidence that the changed combustion conditions do not result in higher air pollutant emissions. The analysis focusses on the effects of the combustion temperature on nitrogen oxides (NOx) and total organic carbon emissions. The evaluation of all continuously monitored emissions shows reduced emission levels compared to the previous years, especially for NOx. [ABSTRACT FROM AUTHOR]

The most sustainable method for treating sewage sludge depends strongly on the situation and local circumstances. In sparsely populated northerly areas are demanding boundary conditions, e.g. cold and long winter, long transport distances and low amounts of generated sludge. In this study, commonly used calculators and emissions coefficients for calculating the greenhouse gas (GHG) emissions from sewage sludge treatment methods were assessed to create a calculator suitable for the Northern Finland context. The calculator was then used to determine which sewage sludge treatment method (composting, anaerobic digestion (AD), incineration (with and without thermal drying)) resulted in the lowest emissions of the GHG gases in different situations in Northern Finland. GHG gases included carbon dioxide (CO 2 ; including biobased), methane (CH 4 ) and nitrous oxide (N 2 O), measured as carbon dioxide equivalents (CO 2 eq). According to the calculator, AD generated the least CO 2 eq emissions of all treatment methods studied. The second best option was incineration of sludge without thermal drying, while the third best was composting or incineration of sludge after thermal drying with e.g. fossil or other fuels. Most of the emissions were generated from the treatment process itself and the share of emissions generated during transport was minimal, despite the long transport distances when all CO 2 emissions (incl. biobased) were considered. The role of users of the end-products and the possibility to use the CO 2 generated were highly important when considering environmental perspective. These results can be utilised when selecting the locally most suitable method. In future, some of the treatment methods (i.e. AD, incineration) with CO 2 capture could be considered carbon sinks, as they also remove biobased CO 2 emissions. [ABSTRACT FROM AUTHOR]

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An aerobic moving bed biofilm reactor (MBBR) was applied to treat landfill leachate generated from a domestic waste incineration plant. Pollutant removal efficiency of this reactor under stable operating condition was studied. The biomass, bacteria species, and microbial metabolism in this reactor were investigated. These results showed that the average removal efficiency of chemical oxygen demand (COD) and ammonia nitrogen in the aerobic MBBR achieved 64% and 97% in the optimum conditions, respectively. The three-dimensional fluorescence spectrum revealed that the content of soluble microbial byproducts from extracellular polymeric substances extraction in suspended sludge was much higher than that on biofilm, and the types of pollutants were various in different regions of the reactor. It also indicated that the MBBR system had a stable, rich and regular microorganism community, including large amounts of nitrifying bacteria and denitrifying bacteria. Scanning electron microscopy suggested that biofilm attached to the packing provided a good anoxic--aerobic micro environment system to achieve a high metabolic activity, which favored COD and ammonia removal. [ABSTRACT FROM AUTHOR]

Addition of cotton stalk (CS) has been proved to promote dramatically the transformation of toxic As 3+ to less toxic As 5+ in the fly ash during municipal sewage sludge (MSS) incineration. However, the fate of arsenic during co-firing of MSS and CS in different operating parameters was still unclear. In the present study, the effects of incineration temperatures and O 2 content in the flue gas on speciation transformation of arsenic during MSS and 70% MSS/30% CS incineration were investigated in a bubbling fluidized bed. The results show that less arsenic is distributed in bottom ash whereas more arsenic is migrated to the fly ash and flue gas, with the temperature increasing from 800 °C to 950 °C. The arsenic capture in fly ash is facilitated predominantly by the condensation and/or physical adsorption of As 2 O 3 (g) at the temperatures from 800 °C to 900 °C. The chemical oxidation of As 2 O 3 (g) is favored by forming various arsenates (As 5+ ) at 950 °C. At low O 2 content from 1% to 5%, some arsenic compounds in MSS such as As 2 S 3 can react with O 2 to produce As 2 O 3 (g), and then more As 2 O 3 (g) is captured in the fly ash by the inherent mineral compounds like CaO through the condensation and/or physical adsorption. Further increasing O 2 content especially to 9% stimulates significantly the oxidation of As 3+ to As 5+ in the fly ash, which is mainly attributed to the chemical reactions between As 2 O 3 (g), various mineral compounds and sufficient O 2 . [ABSTRACT FROM AUTHOR]

Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H 2 SO 4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid. [ABSTRACT FROM AUTHOR]

The treatment of municipal solid waste (MSW) has become an urgently important task of many countries. This objective of this study is to present a novel group multi-attribute decision analysis method for prioritizing the MSW treatment alternatives based on the interval-valued fuzzy set theory. This study allows multiple stakeholders to participate in the process of decision-making and they are also allowed to use linguistic variables to rate the alternatives and determine the weights of the evaluation criteria. The interval-valued fuzzy group decision making trail and evaluation laboratory (DEMATEL) method was developed to determine the weights of the evaluation criteria by considering the independent relationships among these criteria. The multi-actor interval-valued fuzzy grey relational analysis was developed to rank the waste-to-energy scenarios. Four alternative processes for MSW treatment including landfill, anaerobic digestion, incineration, and gasification were studied by the developed model, and the results reveal that the developed model can successfully help the stakeholders to determine the priority sequence of the alternative MSW treatment scenarios. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the plant phosphorus (P) availability of products derived from new P-recovery technologies deployed in wastewater treatment systems against sewage sludge and untreated sewage sludge ashes. Eight P sources were evaluated in a six-week pot experiment with spring barley ( Hordeum vulgare L.) and a soil incubation experiment with anaerobically digested and dewatered sewage sludge (Sludge), sewage sludge ash (Ash), thermochemically treated sewage sludge ash (TrAsh), struvite (Struv), concentrate (Conc), and centrifuged concentrate (Prec) from evaporated reject water, with triple super phosphate (TSP), and composted organic household waste (Comp) as references. All sludge-related materials except struvite came from the same wastewater treatment plant in Denmark. The apparent plant P use efficiency (PUE) of the treatments in the pot experiments was in the following order: Prec (17.0%) > TSP (12.8%) ≥ Conc (12.7%) > Sludge (8.8%) ≥ TrAsh (6.9%) ≥ Struv (6.0%) ≥ Comp (5.8%) > Ash (3.4%). The water-extractable P (WEP) in the incubation experiment largely supported this order and there was a strong correlation between WEP in the incubation experiment and plant P uptake in the pot experiment. Overall, the results of this study demonstrate that it should not automatically be assumed that products recovered with new treatment technologies for P recovery are more effective P fertilizers than the sewage sludge from which they originate. Furthermore, these results indicate that the measurement of water-extractable P after soil incubation could be a suitable proxy for plant P availability. [ABSTRACT FROM AUTHOR]

Sewage sludge (municipal, or industrial) treatment is still a problem in so far that it is not satisfactorily resolved in terms of cost and final disposal. Two common forms of sludge disposal are possible; the first being direct disposal on land (including agriculture) and the second being incineration (ash production), although neither of these methods are universally applied. Simplifying the issue, direct sludge disposal on land is seldom applied for sanitary and environmental reasons, while incineration is not popular for financial (high costs) reasons. Very often medium and large wastewater treatment plants apply anaerobic digestion for sludge hygiene principles, reducing the amount to be disposed and for biogas (energy) production. With the progress in sewage biological treatment aiming at nutrient removal, primary sludge has been omitted in the working processes and only surplus activated sludge requires handling. Anaerobic digestion of waste activated sludge (WAS) is more difficult due to the presence of microorganisms, the decomposition of which requires a relatively long time for hydrolysis. In order to upgrade the hydrolysis effects, several different pre-treatment processes have already been developed and introduced. The additional pre-treatment processes applied are aimed at residual sludge bulk mass minimization, shortening of the anaerobic digestion process or higher biogas production, and therefore require additional energy. The water-energy-waste Nexus (treads of) of the benefits and operational difficulties, including energy costs are discussed in this paper. The intensity of pre-treatment processes to upgrade the microorganism’s hydrolysis has crucial implications. Here a low intensity pre-treatment process, alkalisation and hydrodynamic disintegration - hybrid process - were presented in order to achieve sufficient effects of WAS anaerobic digestion. A sludge digestion efficiency increase expressed as 45% biogas additional production and 52% of the total or volatile solids reduction has been confirmed. [ABSTRACT FROM AUTHOR]

In this study, samples were taken from different types of municipal waste incineration plants in the Pearl River Delta, China. Analyzing the distributive characters of elements and dioxin congeners in fly ash, the method of washing-ball milling was utilized to remove chloride and degrade dioxin in fly ash. The results showed that more than 90% of particles were in the range of 1 ∼ 50 μm and most of dioxin and metals existed in 0.030 ∼ 0.075 mm of particles. K, Na, Cl and Br in fly ash could be removed by washing efficiently, however dioxin and other metals remained in the solid phase. Washing and Fe/Ni-SiO 2 ball-milling method seemed to be the best choice as the dioxin removal rate could reach up to 93.20%. Dioxin could be degraded to low toxic compounds and heterochorides with Fe/Ni as dechlorinating agent. In the process, PCDFs were partly transformed to PCDDs, while too long time of ball-milling was not benefited for dioxin removing. In addition, the phases of calcium such as Ca(OH) 2 , CaCO 3 and CaSO 4 in fly ash could transform from crystal to amorphous. [ABSTRACT FROM AUTHOR]

Decreasing sludge moisture content and increasing sludge organic content are the main difficulties encountered in sludge incineration. The use of inorganic lime as a sludge conditioner decreases sludge organic content and increases the concentration of contaminants, which present severe environmental hazards, in the dewatered filtrate. Thus, in the present study, two agricultural wastes, bamboo powder (BP) and rice husk powder (RHP), were selected to replace lime as sludge conditioners along with cationic polyacrylamide and FeCl 3 . Experimental results showed that BP and RHP acted as skeleton builders that decreased sludge compressibility from 1.08 to 0.76 and 0.78and increased the ultimate heating values of sludge cake. In addition, the addition of BP and RHP decreased the chemical oxygen demand, total nitrogen, and total phosphorus of the filtrate. Coordinated conditioning with BP and RHP decreased capillary suction time, specific resistance to filtration, and moisture content decreased. Therefore, the replacement of quick lime with BP and RHP could help achieve the stable operation of sludge incineration and wastewater treatment plants. [ABSTRACT FROM AUTHOR]

A life cycle impact assessment was applied in an industrial waste incineration plant to evaluate the direct and indirect environmental impacts based on toxicity and non-toxicity categories. The detailed life cycle inventory of material and energy inputs and emission outputs was compiled based on the realistic data collected from a local industrial waste incineration plant, and the Korean life cycle inventory and ecoinvent database. The functional unit was the treatment of 1 tonne of industrial waste by incineration and the system boundary included the incineration plant and landfilling of ash. The result on the variation of the impact by the unit processes showed that the direct impact was decreased by 79.3, 71.6, and 90.1% for the processes in a semi dry reactor, bag filter, and wet scrubber, respectively. Considering the final impact produced from stack, the toxicity categories comprised 91.7% of the total impact. Among the toxicity impact categories, the impact in the eco-toxicity category was most significant. A separate estimation of the impact due to direct and indirect emissions showed that the direct impact was 97.7% of the total impact. The steam recovered from the waste heat of the incineration plant resulted in a negative environmental burden. [ABSTRACT FROM AUTHOR]

Solid waste disposal and management is a critical problem in Nigeria. Annually, a huge quantity of municipal solid waste is generated in Aba. Municipal solid waste disposal in Aba poses severe challenge to environmental safety, public health and welfare of citizens. The situation is made worse by the indiscriminate dumping of refuse at roadsides, streets, waterways and empty lands. The impact of this waste management practice in Aba is environmental deterioration. Efforts to improve waste management in Aba have not recorded significant success. This paper therefore aims to highlight the challenges facing the waste management sector in Aba and proffer solutions on how to improve the sector. [ABSTRACT FROM AUTHOR]

In this study four incineration residues (bottom ash), classified as hazardous wastes on the basis of a leaching test, have been investigated. Analysis of the chemical composition proved to have high contents of heavy metals that during storage could potentially be released into the environment. Therefore, the waste has been subjected to solidification/stabilization (i.e., one of the methods of immobilization of heavy metals) in two ways: with Portland cement and alkali-activated granulated blast furnace slag. It was assumed that bottom ashes will constitute 30% by weight of the dry ingredients. It has been found that although the amount of heavy metals introduced into a matrix along with the mineral waste is significant, the increase in elution of heavy metal ions in the environment is not a consequence. The use of bottom ash from the incineration of hazardous waste may even limit the release of heavy metal ions from cementitious materials. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1074-1082, 2017 [ABSTRACT FROM AUTHOR]

The improper disposal of incinerated sewage sludge ash (ISSA) and air pollution control residues (APCR) from sewage sludge incinerators has become an environmental concern. The physicochemical, morphological and mineralogical characteristics of ISSA and APCR from Hong Kong, and the leachability and risk of heavy metals, are presented in this paper. The results showed that a low hydraulic and pozzolanic potential was associated with the ISSA and APCR due to the presence of low contents of SiO 2 , Al 2 O 3 and CaO and high contents of P, S and Cl (especially for APCR). Although high concentrations of Zn and Cu (especially for ISSA) followed by Ni, Pb and As, Se were detected, a low leaching rate of these metals (especially at neutral and alkaline pH) rendered them classifiable as non-hazardous according to the U.S. EPA and Chinese national regulatory limits. The leached metals concentrations from ISSA and APCR were mainly pH dependent, and metals solubilization occurred mainly at low pH. Different leaching tests should be adopted based on the simulated different environmental conditions and exposure scenarios for assessing the leachability as contrasting results could be obtained due to the differences in complexing abilities and final pH of the leaching solutions. [ABSTRACT FROM AUTHOR]

Co-incineration of sewage sludge in cement kilns can be used for its disposal. In the present study, samples were collected from three cement production runs where sewage sludge and other wastes (e.g. municipal solid waste, waste acid and wet sewage sludge) were co-processed. The samples were analyzed for polychlorinated biphenyls (PCBs). The dioxin-like (dl)-PCB concentrations in the stack gases from run 1, 2, and 3 were 344.6, 548.7, and 104.3 pg m −3 , respectively. The toxic equivalency (TEQs) values for runs 1, 2, and 3 were 5.6, 8.9, and 0.7 pg TEQ Nm −3 , respectively. Calculation of net emissions for the three runs indicated that the co-incineration of other waste in addition to sewage sludge in cement kilns would not increase emission of the dl-PCBs. PCB concentrations in samples from the suspension boiler and humidifier tower, kiln-end bag filter, and cyclone preheater were much higher than those in samples from the kiln head area, indicating that these stages will be important for controlling PCB formation. Chlorinated biphenyl (CB)-77, CB-105 and CB-118 were the major dl-PCB congeners, CB-52, CB-101 were the major indicator PCB congeners, and tetra-CB to hexa-CB were the major homologues for the total input or output materials. [ABSTRACT FROM AUTHOR]

Sustainable development and circular economy rules force the global fertilizer industry to develop new phosphorous recovery methods from alternative sources. In this paper a phosphorus recovery technology from Polish industrial Sewage Sludge Ashes was investigated (PolFerAsh – Polish Fertilizers form Ash). A wet method with the use of mineral acid and neutralization was proposed. Detailed characteristic of SSA from largest mono-combustion plans were given and compared to raw materials used on the market. The technological factors associated with such materials were discussed. The composition of the extracts was compared to typical industrial phosphoric acid and standard values characterizing suspension fertilizers. The most favorable conditions for selective precipitation of phosphorus compounds were revealed. The fertilizers obtained also meet EU regulations in the case of the newly discussed Cd content. The process was scaled up and a flow mass diagram was defined. [ABSTRACT FROM AUTHOR]

This research compares and contrasts the physical and chemical characteristics of incinerator sewage sludge ash (ISSA) and pyrolysis sewage sludge char (PSSC) for the purposes of recovering phosphorus as a P-rich fertiliser. Interest in P recovery from PSSC is likely to increase as pyrolysis is becoming viewed as a more economical method of sewage sludge thermal treatment compared to incineration. The P contents of ISSA and PSSC are 7.2–7.5% and 5.6%, respectively. Relative to the sludge, P concentrations are increased about 8-fold in ISSA, compared to roughly 3-fold in PSSC. Both PSSC and ISSA contain whitlockite, an unusual form of calcium phosphate, with PSSC containing more whitlockite than ISSA. Acid leaching experiments indicate that a liquid/solid ratio of 10 with 30 min contact time is optimal to release PO 4 -P into leachate for both ISSA and PSSC. The proportion of P extracted from PSSC is higher due to its higher whitlockite content. Heavy metals are less soluble from PSSC because they are more strongly incorporated in the particles. The results suggest there is potential for the development of a process to recover P from PSSC. [ABSTRACT FROM AUTHOR]

Acrylonitrile-butadiene-styrene (ABS) is one of hazardous halogenic plastics which containing brominated flame-retardants (BFRs) is considered as toxic wastes due to releasing hydrogen bromide and brominated dioxins through incineration or disposal activities. In present, recycling is aimed as a sustainable plastic waste management of ABS containing BFRs in ways that minimize the potential impact on human health and environment. This study was conducted to facilitate the separation of ABS plastics from heavy plastic mixture by froth flotation after surface rearrangement of ABS with mild heat treatment for its recycling. Hydrophilic moieties would be more likely to develop on the mild heat-treated ABS surfaces than on other plastics perhaps due to the difference of molecular mobility. This provides an excellent base for selective separation of ABS by froth flotation technique. As a result of froth flotation after mild heat treatment, about 97% of ABS with 100% purity was selectively separated from heavy plastics. The detailed mechanism for the selective separation of the ABS in the treatment (froth flotation after mild heat treatment) was discussed. Finally, this study facilities selective separation application effective and inexpensive method for of ABS from waste plastics. [ABSTRACT FROM AUTHOR]

Phosphorus deposits around the world are rapidly depleting, therefore phosphorus recovery methods are gaining more and more interest both in science and industry. This article presents the main methods of phosphorus recovery from sewage sludge. The described approaches are divided in two groups: phosphorus recovery from sewage sludge and leachate, and recovery of phosphorus from sewage sludge ashes. The latter seems to have more advantages connected with both ecological and economical aspects. The need for development of “no solid waste generation” strategy is becoming more and more urgent. The concept of comprehensive management of all solid residues after what is currently considered the most ecological process of sewage sludge incineration connected with phosphorus recovery based on acidic extraction, is described in the article. Solid residues after phosphorus recovery from sewage sludge ashes by means of acidic extraction can be stabilized with solid residues after sewage sludge incineration exhaust gas treatment. Such an approach may enable production of phosphoric raw material together with stabilized construction material. Advantages and disadvantages of the discussed approaches are given. An analysis of the composition of ashes produced in different sewage sludge treatment plants indicates that the proposed technology could be successfully applied in most of such units, especially because the concentrations of elements such as K, Mg, Na, P are sufficiently high, respectively 1.5–12.1 g/kg; 9.9–14.9 g/kg; 3.6–13,3 g/kg and 27,4–99,0 g/kg. However, a phosphorus recovery method should be developed separately for each treatment plant. Only then all comprehensive management methods will be ecologically and economically justified. Analytical methods which could be of use at every step of designing a proper phosphorus recovery process are described. [ABSTRACT FROM AUTHOR]

Phosphorus is a limited non-renewable resource that is indispensable as an essential nutrient for the growth of organisms in most ecosystems. To demonstrate the reuse of phosphorus resources from sewage sludge ash (SSA), experiments were conducted in a pilot circulating fluidized bed kiln. The experimental results demonstrated that high temperature and calcium oxide (CaO) were beneficial for the transformation of non-apatite inorganic phosphorus (NAIP) to apatite phosphorus (AP). Thermogravimetric differential scanning calorimetry analysis was combined with X-ray diffraction measurements to simulate the process of sewage sludge incineration of the crystal phase transition between aluminium phosphate (AlPO 4 ) and CaO, forming stable AP in the temperature range of 675–850 °C. Additionally, 89.29% of the phosphorus was enriched in sewage sludge bottom ash and 5.61% was distributed in fly ash, with AP being the primary component in the fly ash at 850 °C. AP content generally increased with decreasing particle size, whereas NAIP content exhibited the opposite tendency, and became stable when the particle size was less than 37.5 μm. [ABSTRACT FROM AUTHOR]

The aim of this research is to present the possibility of using the sewage sludge ash (SSA) generated in incineration plants as a secondary source of phosphorus (P). The importance of issues related to P recovery from waste materials results from European Union (UE) legislation, which indicated phosphorus as a critical raw material (CRM). Due to the risks of a shortage of supply and its impact on the economy, which is greater than other raw materials, the proper management of phosphorus resources is required in order to achieve global P security. Based on available databases and literature, an analysis of the potential use of SSA for P-recovery in Poland was conducted. Currently, approx. 43,000 Mg/year of SSA is produced in large and small incineration plants and according to in the Polish National Waste Management Plan 2014 (NWMP) further steady growth is predicted. This indicates a great potential to recycle phosphorus from SSA and to reintroduce it again into the value chain as a component of fertilisers which can be applied directly on fields. The amount of SSA generated in installations, both large and small, varies and this contributes to the fact that new and different P recovery technology solutions must be developed and put into use in the years to come (e.g. mobile/stationary P recovery installations). The creation of a database focused on the collection and sharing of data about the amount of P recovered in EU and Polish installations is identified as a helpful tool in the development of an efficient P management model for Poland. [ABSTRACT FROM AUTHOR]

Experiments and thermodynamic equilibrium calculations were performed to investigate the behavior of Cd during sewage sludge incineration. The chemical equilibrium calculations indicated that chlorine significantly increased the volatilization of Cd in the form of CdCl2 - In addition, Si02-containing materials can function as sorbents for stabilizing Cd. The effect of PVC added to the sludge on the migration of Cd in the sludge was greater than that of NaCl. As the temperature increased, both organic and inorganic chlorides reduced the Cd distribution in the bottom ash. The chloride concentration, and the incineration time exhibited insignificant changes in Cd emission. With the addition of either NaCl or PVC into the sludge, the phases of Cd present in the bottom slag were primarily present in the form of silicaalumina oxides or multi-metal oxide, which could inhabit the Cd volatilization. Water Environ. Res., 88, 2245 (2016). [ABSTRACT FROM AUTHOR]

In quantitative terms, sludge produced in the process of municipal wastewater treatment represents a small part of the total waste generated in municipal sources - its quantity represents only a few percent of the generated mass of municipal waste. However, the threats it brings, do not allow it to be neglected while designing the wastewater treatment process. At the same time, with increasing requirements regarding the quality of sewage discharged into the environment, there is an increase in the amount of sludge produced in wastewater treatment processes. In recent years, the share of thermal treatment of municipal sewage sludge has risen sharply - about 12 modern sludge incineration plants have been built and construction of new ones is considered. During more than a four-year operation of the sewage sludge incineration plant in the Combined Sewage Treatment Plant in Lodz (GOS) a large ammonia emission from the combustion process was observed. So, a decision was taken to examine this process. The paper presents results of ammonia emission from the combustion of sewage sludge from GOS as a function of temperature. [ABSTRACT FROM AUTHOR]

Electro-osmotic dewatering (EDW) is one of the effective deeply dewatering technologies that is suitable for treating sludge with 55–80% of moisture content. Regarding EDW as the pre-treatment process of drying or incinerating, this article investigated the drying characteristics of electro-osmosis-dewatered sludge, including shear stress test, drying curves analysis, model analysis, and energy balance calculation. After EDW pre-treatment, sludge adhesion was reduced. The sludge drying rate was higher compared to the non-pre-treated sludge, especially under high temperatures (80–120°C). In addition, it is better to place the sludge cake with cathode surface facing upward for improving the drying rate. An adjusted model based on the Logarithmic model could better describe the EDW sludge drying process. Using the energy balance calculation, EDW can save the energy consumed in the process of sludge incineration and electricity generation and enable the system to run without extra energy input. [ABSTRACT FROM PUBLISHER]

The compositions of food wastes and their co-gasification producer gas were compared with the existing data of sewage sludge. Results showed that food wastes are more favorable than sewage sludge for co-gasification based on residue generation and energy output. Two decentralized gasification-based schemes were proposed to dispose of the sewage sludge and food wastes in Singapore. Monte Carlo simulation-based cost-benefit analysis was conducted to compare the proposed schemes with the existing incineration-based scheme. It was found that the gasification-based schemes are financially superior to the incineration-based scheme based on the data of net present value (NPV), benefit-cost ratio (BCR), and internal rate of return (IRR). Sensitivity analysis was conducted to suggest effective measures to improve the economics of the schemes. [ABSTRACT FROM AUTHOR]

The article reports on implementation of the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Sewage Sludge Incineration Units that requires sewage sludge incinerators (SSIs) to meet ceiling limits on emissions of contaminants like carbon monoxide.