Land Application Of Sewage Sludge Research Articles

Concentrations and sources of an emerging pollutant, decabromodiphenylethane (DBDPE), in sewage sludge for land application

The presence of an emerging brominated flame retardant, decabromodiphenylethane (DBDPE), has been confirmed in Spanish sewage sludge. Thirty one samples from different urban wastewater treatment plants (WWTPs) were analyzed for this brominated flame retardant. DBDPE was positively identified and quantified in all samples at lower concentrations (47.0 ± 29.7 ng/g dry weight (dw); mean ± SD) than those obtained for decabromodiphenyl ether (BDE-209) (290 ± 236 ng/g dw; mean ± SD) in a previous study. Influence of the WWTP characteristics in the pollutant levels was evaluated. No significant correlations were obtained between DBDPE concentrations and the population or sewage sludge production rate associated with the plants, neither wastewater treatment method. Sources of DBDPE in the sludge were also evaluated. Data indicate a common origin for DBDPE and BDE-209, which may be related to leaching processes during the use and disposal of consumer products containing these chemicals. Nevertheless, DBDPE contents are not influenced by industrial activities, which suggests that the infusion of DBDPE commercial mixture is not a source of this chemical into the environment, and indicates that the use of DBDPE in the Spanish industry is still low compared to deca-BDE.

Assessment of Arsenic and Selenium Concentration with Chlorophyll Contents of Sugar Beet (Beta vulgaris var.saccharifera) and Wheat (Triticum aestivum) Exposed to Municipal Sewage Sludge Doses

The present study was conducted to assess the suitability of sewage sludge amendment in soil for Beta vulgaris var. saccharifera (sugar beet) and Triticum aestivum (wheat) by evaluating the arsenic and selenium accumulation and physiological responses of plants grown at 10%, 25%, and 50% sewage sludge amendment rate. Sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently with higher accumulation in plant parts. The chlorophyll contents increased after the sewage sludge treatments except for 50%. The sewage sludge amendment led to a significant increase in arsenic and selenium concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency. The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake in the leaves and root concentrations of arsenic and selenium in plants as compared to those grown on unamended soil. Accumulation was more in roots than shoots and leaves for most of the heavy metals. Concentrations of arsenic and selenium were more than the permissible limits of national standards in the edible portion of sugar beet and wheat grown on different sewage sludge amendments ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet and wheat may not be a good option due to risk of contamination of arsenic and selenium.

PBDEs in Italian sewage sludge and environmental risk of using sewage sludge for land application

Polybrominated diphenyl ethers (PBDEs) were determined in sewage sludge samples collected from eight Italian wastewater treatment plants (WWTPs) between June 2009 and March 2010. Total PBDE concentrations ranged from 158.3 to 9427 ng g −1 dw, while deca-BDE (BDE-209) (concentrations ranging from 130.6 to 9411 ng g −1 dw) dominated the congener profile in all the samples, contributing between 77% and 99.8% of total PBDE. The suitability of using a magnetic particle enzyme-linked immunoassay (ELISA) to analyse PBDEs in sewage sludge was also tested. The ELISA results, expressed as BDE-47 equivalents, were well correlated with those obtained by GC–NCI–MS, with correlation coefficients ( r 2) of 0.899 and 0.959, depending on the extraction procedure adopted. The risk assessment of PBDEs in sewage sludge addressed to land application was calculated. PEC soil values compared to the relative PNEC soil for penta and deca-BDE suggests that there is a low risk to the soil environment.

Heavy Metal Phytotoxicity to Radish (Raphanus sativus L.) in a Digested Sludge-amended Gangetic Alluvium

A limiting factor in land application of sewage sludge is the resultant heavy metal accumulation in soils followed by biomagnification in the food chain, posing a potential hazard to animal and human health. In view of this fact, pot experiments were conducted to evaluate the effect of digested sludge application to soil on phytotoxicity of heavy metals such as Cd, Cr, Ni, and Pb to radish (Raphanus sativus L.) plants. Increasing sludge levels resulted in increased levels of DTPA-extractable heavy metals in the soil. Cadmium was the dominant metal extracted by DTPA followed by Ni, Pb, and Cr. The extractability of metals by DTPA tended to decrease from the first to the second crop. Dry matter yield of radish increased significantly as a function of increasing sludge treatments. Soil application of sludge raised the concentration of one or more heavy metals in plants. Shoots contained higher concentrations of Cd, Cr, and Ni than the roots of radish plants. Shoot concentrations of Cd, Cr, Ni, and Pb were within the tolerance levels of this crop at all rates of sludge application. Shoot as well as root concentration of Cd was above 0.5 mg kg−1, considered toxic for human and animal consumption. The levels of DTPA-extractable Cd and Ni were less correlated while those of Cr and Pb were more correlated with their respective shoot and root contents. The results emphasize that accumulation of potentially toxic heavy metals in soil and their build-up in vegetable crops should not be ignored when sludge is applied as an amendment to land.

Effect of Organic Matter Oxidation on the Fractionation of Copper, Zinc, Lead, and Arsenic in Sewage Sludge and Amended Soils

Long-term land application of sewage sludge (SS) has caused concern over the potential release of trace metals into the environment following the degradation of organic matter (OM). This study was performed to assess the impact of OM degradation on the relative distribution of Cu, Zn, Pb, and As in SS and SS-amended soils. Three SSs of different ages and two soils treated with SS were subjected to incubation and direct chemical oxidation using diluted HO, followed by a sequential extraction. The majority of Cu, Pb, and As were bound to OM, whereas the majority of Zn was bound with Fe/Mn oxides for all three SSs. Incubation of SS for 6 mo did not result in a substantial decrease in OM content or a change in the relative distribution of Cu, Zn, Pb, and As. Direct OM oxidation to 30 and 70% by diluted HO resulted in a significant decrease in organically bound Cu but increased its exchangeable, carbonate-bound, and Fe/Mn-bound fractions. Oxidation of OM slightly decreased organically bound Zn but significantly increased exchangeable Zn in all SSs. Oxide- and carbonate-bound Zn also decreased following OM oxidation. Exchangeable fractions of As and Pb were minute before and after OM degradation, indicating that release into the environment would be unlikely. The relative distribution of Cu, Zn, Pb, and As in SS-treated soils was similar to that of SS, suggesting a dominant role of SS properties in controlling metal distribution following OM oxidation. Overall, OM oxidation increased the mobility and bioavailability of Zn and Cu, whereas it had less impact on Pb and As.

Toward a Consensus View on the Infectious Risks Associated with Land Application of Sewage Sludge

The science linking processed sewage sludge (biosolids) land application with human health has improved in the last ten years. The goal of this review is to develop a consensus view on the human health impacts associated with land-applying biosolids. Pre-existing risk studies are integrated with recent advances in biosolids pathogen exposure science and risk analysis. Other than accidental direct ingestion, the highest public risks of infection from land application are associated with airborne exposure. Multiple, independent risk assessments for enteroviruses similarly estimate the yearly probabilities of infection near 10(-4). However, the inclusion of other emerging pathogens, specifically norovirus, increases this yearly infectious risk by over 2 orders of magnitude. Quantitative microbial risk assessment for biosolids exposure more effectively operates as a tool for analyzing how exposure can be reduced rather than being used to assess "safety". Such analysis demonstrates that the tradition of monitoring pathogen quality by Salmonella spp. and enterovirus content underestimates the infectious risk to the public, and that a rigorous biosolids pathogen treatment process, rather than extending community separation distances, is the most efficient method for reducing pathogen exposure and infectious risk.

Phosphorus Paradox Scarcityand Overabundance of a Key Nutrient

In between shepherding the United States through the Great Depression and bracing the country for war in Europe, then-President Franklin Roosevelt took a moment in 1938 to tell Congress about phosphorus.1 More specifically, he spoke about phosphates, the most commonly commercially exploited form of phosphorus. Roosevelt’s was not a scientific presentation but a cautious alert about the critical role this element plays in agricultural production. Private interests were exporting increasing amounts of the country’s phosphates to markets abroad, he warned. Given the prospect that this vital constituent of fertilizer could come into short supply domestically, Roosevelt recommended framing a formal policy to deal with a strategic issue. “The disposition of our phosphate deposits should be regarded as a national concern,” he said. “The situation appears to offer an opportunity for this nation to exercise foresight in the use of a great national resource heretofore almost unknown in our plans for the development of the nation.”1 In spite of Roosevelt’s call, no phosphate policy was forthcoming. More than seven decades on, the phrase “heretofore almost unknown” still echoes in many discussions about phosphorus. Meanwhile, the significance of phosphates is even more profound today than it was in the 1930s. Phosphate rock has emerged as a globally traded commodity linked to a diverse set of politically charged debates, ranging from environmental degradation and threats to human health to food security and agricultural sovereignty.

A Critical Review of the U.S. EPA's Risk Assessment for the Land Application of Sewage Sludge

Sewage sludge is a complex mixture of inorganic and organic materials and pathogens generated by the treatment of domestic sewage. Section 40 of the Code of Federal Regulations Part 503 regulates the land application of sewage sludge based on pathogen content and sets standards for nine inorganic chemicals. It is believed that the Part 503 standards are protective of human health and the environment and that sewage sludge applied to land poses little risk. A critical inspection of the pertinent literature, however, reveals that the standards were based on outdated methods, outdated data, inaccurate data, and flawed assumptions, leading to underestimation of risk. The standards are not sufficiently protective, and even if changes were made, sewage sludge is so complex that it is very unlikely it could be monitored to ensure the protection of human health and the environment. For these reasons, the practice of land application of sewage sludge must be discontinued.

Land application of sewage sludge (biosolids) in Australia: risks to the environment and food crops

Australia is a large exporter of agricultural products, with producers responsible for a range of quality assurance programs to ensure that food crops are free from various contaminants of detriment to human health. Large volumes of treated sewage sludge (biosolids), although low by world standards, are increasingly being recycled to land, primarily to replace plant nutrients and to improve soil properties; they are used in agriculture, forestry, and composted. The Australian National Biosolids Research Program (NBRP) has linked researchers to a collective goal to investigate nutrients and benchmark safe concentrations of metals nationally using a common methodology, with various other research programs conducted in a number of states specific to regional problems and priorities. The use of biosolids in Australia is strictly regulated by state guidelines, some of which are under review following recent research outcomes. Communication and research between the water industry, regulators and researchers specific to the regulation of biosolids is further enhanced by the Australian and New Zealand Biosolids Partnership (ANZBP). This paper summarises the major issues and constraints related to biosolids use in Australia using specific case examples from Western Australia, a member of the Australian NBRP, and highlights several research projects conducted over the last decade to ensure that biosolids are used beneficially and safely in the environment. Attention is given to research relating to plant nutrient uptake, particularly nitrogen and phosphorus (including that of reduced phosphorus uptake in alum sludge-amended soil); the risk of heavy metal uptake by plants, specifically cadmium, copper and zinc; the risk of pathogen contamination in soil and grain products; change to soil pH (particularly following lime-amended biosolids); and the monitoring of faecal contamination by biosolids in waterbodies using DNA techniques. Examples of products that are currently produced in Western Australia from sewage sludge include mesophilic anaerobically digested and dewatered biosolids cake, lime-amended biosolids, alum sludge and compost.

Temperature-phased anaerobic digestion (TPAD) to obtain class A biosolids: A semi-continuous study

Regulations regarding the land application of sewage sludge require the performance of highly efficient treatments for pathogen reduction, such as temperature-phased anaerobic digestion (TPAD). Several semi-continuous experiments with different solid residence times (SRTs) have been made to find the best combination - TPAD 15/15, TPAD 5/15, TPAD 3/15 or TPAD 3/12. TPAD systems showed better performance in terms of VS destruction, gas production, sludge dewaterability, and process stability at total SRT of 15 days, compared with single-stage mesophilic or thermophilic digestion at the same SRT. Average VS reductions (VSR) using the overall TPAD 5/15 (78%), TPAD 3/15 (87%), and TPAD 3/12 (87%) were significantly higher than mesophilic control operating with an SRT of 15 days (40% VSR). The best results were obtained for TPAD 3/15 with 0.62 LCH(4) g(-1) VS(r), faecal coliform 10(3) MPN/g TS, and Salmonella spp. 1 MPN/4 g TS. Although both TPAD 3/15 and TPAD 3/12 were efficient enough to obtain Class A biosolids.

Recycling of Coal Fly Ash and Paper Waste to Improve Low Productive Red Soil in Okinawa, Japan

AbstractCoal fly ash (CFA) and paper waste (PW) related environmental problems and its recycling techniques have been a major challenge to society. Therefore, it is of crucial importance to develop new recycling methods for CFA and PW. This work proposes a potential new way of developing synthetic aggregates (SA) using CFA, PW, starch waste and ammonium sulfate (AS) as a granular nitrogen fertilizer medium, and their utilization as a soil amendment to improve crop production in the low productive acidic red soil of Okinawa, Japan. Three types of SA with three different nitrogen (N) percentages were produced and used to amend acidic red soil in a pot experiment for the cultivation of Komatsuna, which is also called as Japanese mustard spinach (Brassica rapa var. pervidis). SA had a low bulk density (0.58–0.62 g/cm3), high water holding capacity (0.60–0.64 kg/kg), high saturated hydraulic conductivity (2.34·10–2 cm/s), high mean weight diameter (MWD) (4.32–4.48 mm), alkaline pH (8.58–8.61), high electrical conductivity (EC) (82.18–84.35 mS/m) and high carbon (C) content (68.71–70.07 g/kg) in comparison with the acidic red soil. The trace element concentrations of the developed SA were below the maximum pollutant concentration of individual metals for land application of sewage sludge given by the US Environmental Protection Agency. Scanning electron microscopic (SEM) studies showed the higher structural surface area of SA, where round shaped CFA particles were embedded into the fibrous PW matrix. Incorporation of SA into the acidic red soil not only enhanced soil fertility but also improved the physical and chemical properties of the soil compared to soil without SA addition. SA addition to the acidic red soil significantly increased the growth and yield parameters of Komatsuna compared to soil without SA addition.

Determination of the persistence of pharmaceuticals in biosolids using liquid-chromatography tandem mass spectrometry

Sludge generated in waste water treatment process can be a major sink for some pharmaceutical and personal care products (PPCPs). The land application of sewage sludge (in the form of biosolids in the United States) can therefore potentially introduce PPCPs into the environment. After treatment, biosolids are often subjected to a storage period before land application. However, little information is available with regard to the fate of PPCPs in biosolids during the storage. In this work, the persistence of seven pharmaceuticals and one antibacterial was evaluated using ultrasonic extraction and liquid-chromatography tandem mass spectrometry (LC–MS/MS). The impacts of aeration and sunlight exposure were investigated. During the experiment, no elimination was observed for carbamazepine, triclosan, and ciprofloxacin while elimination was found for tetracycline, doxycycline, clindamycin, erythromycin, and clarithromycin. Using an availability-adjusted kinetic model, the 50% dissipation time was 37 to >77 d for tetracycline, 53 to >77 d for doxycycline, 1.0–1.6 d for clindamycin, 1.1–1.9 d for clarithromycin, and 7.0–17 d for erythromycin. Those compounds were found more persistent under anaerobic conditions than aerobic condition with a longer 50% dissipation time by a factor of 1.5–2. However, minor impact was observed from sunlight irradiation.

Study of heavy metal in sewage sludge and in Chinese cabbage grown in soil amended with sewage sludge

The study was performed to investigate the heavy metal content and availability for crops in sewage sludge and its accumulation in Chinese cabbage grown in sewage sludge amended soil. We determined the total and chemical fraction of As, Cr, Cd, Pb, Ni, Cu, Zn, Fe, Mg and Mn in sewage sludge and the total content of these metals in Chinese cabbage grown in soil amended with sewage sludge. Total content of all metals (except for As) was below the top limits for land application of sewage sludge in China. The majority of As, Cd, Pb, Zn and Fe was present in the residual fraction (70 – 95%) of the total concentration, and 21% of Cd, 59% of Cr and 56% of Cu were present in oxidizable fraction in sewage sludge. Most of the content of metals increased in Chinese cabbage with the increase in sludge amendments ratio, and the content of heavy metal As, Cd, Cr and Zn exceeded the top limits of metals content in China. Our results suggested that application of sewage sludge could enhance the output of vegetable while the risk of heavy metal should be of concern.

Studies on land application of sewage sludge and its limiting factors

Field experiments were conducted to study the effect of sewage sludge application on the heavy metal content in soils and grasses. The sewage sludge was obtained from Northern Shenyang Wastewater Treatment Plant, China, and applied at 0, 15, 30, 60, 120 and 150 t ha −1. Native grasses Zoysia japonica and Poa annua were chosen as experimental plants. The experimental results showed that nutrient content of the soil, especially organic matter, was increased after sewage sludge application. The grass biomass was increased and the grass growing season was longer. Heavy metal concentrations in the soil also increased; however, the Zn content did not exceed the stringent Chinese environmental quality standard for soil. Pb and Cu did not exceed the standard for B grade soil, but Cd concentration in soil amended by sewage sludge has exceeded the B grade standard. Therefore, it is suggested that the sewage sludge produced from the wastewater treatment plant should not be applied to farmland, for which B grade soil or better is required. The sludge is suitable for application to forestry and grasslands or nurseries where food chain contamination with cadmium is not a concern.

Land application of sewage sludge: A soil columns study

A column study was conducted to assess the potential Cr, Ni, Cu, Zn, Cd and Pb movement through a reconstructed soil profile to which surface composted sewage sludge was applied. Sewage sludge was mixed into the top 100 mm of each column at the rates of 357 (H), 223 (M) and 22 Mg·ha-1 (L). Treatment H was calculated according to the critical soil concentration and treatments M and L were calculated according to the amount of metals which may be added to agricultural land on 10 yr average (M) and 1 yr (L) according to European legislation. Soil columns were leached with 5 000 mℓ of water. After leaching, soil columns were sampled at depth intervals of 0 to 100, 100 to 300, 300 to 500 and 500 to 840 mm. Metal balance accounted for over 97% of metals and over 86% of metals were retained in the first 100 mm of the column. The average percentage of metals leached decreased in the order Cd (0.04%) > Cu (0.02) ~ Ni (0.02) ~ Zn (0.02) > Pb (0.01) ~ Cr (0.01). The maximum metal concentration in leachates was lower than the limit value for irrigation water but metal concentrations exceeded the drinking water levels for Pb and Ni in all treatments. Thus, harmful health effects may result from the application of sewage sludge. Water SA Vol.31 (3) 2005: pp.309-318

Sustainable sludge treatment: dilemmas in future research and development

Sewage sludge is a serious problem due to the high treatment costs and the risks to environment and human health. Looking to the future the question arises of which sludge research and development issues are most important. Based on a brief evaluation of current sludge treatment systems and research results it can be concluded that land application of sewage sludge remains one of the most attractive options. However, more research into the health risks is necessary to make this method worldwide more acceptable. Recovery of energy from sludge is becoming more and more attractive. High thermal processes are interesting if sludge does not satisfy the guidelines for land application. Integration of these high thermal processes with existing industrial activities or other thermal waste treatment processes can be very attractive. Research into dewatering and drying can make the energy recovery more efficient. Processes for recovery of valuable products from sludge such as aquatic worms and P-compounds are potentially very attractive but their feasibility strongly depends on the marketing and market value of these products. It is expected that supercritical sludge treatment and direct production of electricity require still a long research and development path.

Potential benefits and risks of land application of sewage sludge

Sewage sludge, also referred as biosolids, is a byproduct of sewage treatment processes. Land application of sewage sludge is one of the important disposal alternatives. Characteristics of sewage sludge depend upon the quality of sewage and type of treatment processes followed. Being rich in organic and inorganic plant nutrients, sewage sludge may substitute for fertilizer, but availability of potential toxic metals often restricts its uses. Sludge amendment to the soil modifies its physico-chemical and biological properties. Crop yield in adequately sludge-amended soil is generally more than that of well-fertilized controls. Bioavailability of metals increases in sludge amended soil at excessive rates of application for many years. Plants differ in their abilities to absorb sludge-derived metals from the soil. The purpose of this paper is to review the available information on various aspects of sewage sludge application on soil fertility and consequent effects on plant production to explore the possibility of exploiting this byproduct for agronomy and horticulture.

Use of citric acid for heavy metals extraction from contaminated sewage sludge for land application

Recent studies revealed that organic acids such as citric and oxalic acids seemed to be more promising as chemical extracting agents for removal of heavy metals from contaminated sludge, since they are biodegradable and can attain a higher metal extraction efficiency at mildly acidic pH compared to other extracting agents. Results of a lab-scale study on the efficiency of citric acid in the extraction of chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sludge, revealed that citric acid seemed to be highly effective in extracting Cr (at 100%), Cu (at 88%), Ni (at 98%) and Zn (at 100%) at pH 2.33, mostly at 5 days leaching time except for Cu and Zn, which are at 1 day and 2 h contact times respectively. Lead removal at the same pH was also high at 95% but at a longer leaching time of 11 days. At pH 3, citric acid seemed to be highly effective in extracting Pb (at 100%) at 1 day leaching time, although higher removals were also attained for Ni (70%) and Zn (80%) at only 2 h leaching time. Chemical speciation studies showed that Cr, Cu and Ni in the sludge sample seem to predominate in residual fractions, while Pb and Zn were found mostly bound to organic and inorganic matter forms, hence the potential of the sludge for land application.

Characteristics of sewage sludge and distribution of heavy metal in plants with amendment of sewage sludge

In order to better understand land application of sewage sludge, the characterization of heavy metals and organic pollutants were investigated in three different sewage sludges in Shanghai City, China. It was found that the total concentrations of Cd in all of sewage sludge and total concentrations of Zn in Jinshan sewage sludge, as well as those of Zn, Cu, and Ni in Taopu sludge are higher than Chinese regulation limit of pollutants for sludge to be used in agriculture. Leachability of Hg in all of studied samples and that of Cd in Taopu sewage sludge exceed the limit values of waste solid extraction standard in China legislation. Based on the characteristics for three kinds of sewage sludge, a pot experiment was conducted to investigate the effect of soil amended with Quyang sewage sludge on the accumulation of heavy metal by Begonia semperflorens-hybr; Ophiopogon japonicus (L.F.) Ker-Gaw; Loropetalum chindense-var. rubrum; Dendranthema morifolium; Viola tricolor; Antirrhinum majus; Buxus radicans Sieb; Viburnum macrocephalum; Osmuunus fragrans Lour; Cinnamomum camphora siebold and Ligustrum lucidum ait. Results showed that 8 species of plant survived in the amended soil, and moreover they flourished as well as those cultivated in the control soil. The heavy metal concentration in plants varied with species, As, Pb, Cd and Cr concentration being the highest in the four herbaceous species studied, particularly in the roots of D. morifolium. These plants, however, did not show accumulator of As, Pb, Cd and Cr. The highest concentration of Ni and Hg was found in the roots of D. morifolium, followed by the leaves of B. semperflorens-hybr. Levels of Zn and Cu were much higher in D. morifolium than in the other plant species. D. morifolium accumulated Ni, Hg, Cu and Zn, which may contribute to the decrease of heavy metal contents in the amended soil. Treatment with sewage sludge did not significantly affect the uptake of heavy metals by the L. chindense-var. rubrum, however, it significantly affected the uptake of heavy metals by D. morifolium.

PCDD/F, PAH and heavy metals in the sewage sludge from six wastewater treatment plants in Beijing, China

In order to better understand land application of sewage sludge, the characterization of heavy metals, PCDD/F and PAHs in sewage sludge was investigated from six different wastewater treatment plants (WWTP) in Beijing City, China. It was found that the total concentrations of Zn in Wujiacun (WJC) sewage sludge, and Cd and Hg in sewage sludge generated from all of the six different places are higher than Chinese regulation limit of pollutants for sludge to be used for agriculture ( GB18918-2002). The levels of 16 PAHs that have been categorized as priority pollutants by US EPA in the sewage sludge samples varied from 2467 to 25 923 μg/kg (dry weight), the highest values of 25 923 μg/kg being found in WJC WWTP. The concentrations of Benzo[ a]pyrene were as high as 6.1 mg/kg dry weight in WJC sewage sludge, exceeding the maximum permitted content by GB18918-2002. Individual PAH content varies considerably with sewage samples. The ratios of anthracene to anthracene plus phenanthrene (An/178), benz[ a]anthracene to benz[ a]anthracene plus chrysene (BaA/228), indene[1,2,3- cd]pyrene to indene[1,2,3- cd]pyrene plus benzo[ g, h, i]perylene (In/In + BP), and fluoranthene to fluoranthene plus pyrene (Fl/Fl + Py) suggest that petroleum and combustion of fossil fuel were the dominant contributions for the PAHs in sewage sludge. The concentrations of total PCDD/F in the sewage sludge ranged from 330 to 4245 pg/g d.w. The toxicity equivalent concentrations is between 3.47–88.24 pg I-TEQ according to NATO/CCMS, which is below Chinese legislation limit value proposed for land application. The PCDD/F congener/homologue profiles found in the Beijing samples indicated that the high chlorinated PCDD/F contamination might originate mainly from PCP-related source and depositional sources while the low chlorinated PCDD/F homologues could be originating from incineration or coal combustion. The major source of PCDD/Fs in Beijing sludge is still unclear.