A risk-based methodology for deriving quality standards for organic contaminants in sewage sludge for use in agriculture—Conceptual Framework

Schowanek, Diederik; Carr, Richard; David, H. K.; Douben, Peter E. T.; Hall, Jennifer; Kirchmann, Holger; Patria, L.; Sequi, P.; Smith, Stephen R.; Webb, Simon

doi:10.1016/j.yrtph.2004.07.002

Cited by 76 publications

(34 citation statements)

References 72 publications

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“…This equates to an application rate of approximately 1 dry MT/ha/yr. While quantitative limits vary among the European countries, most limit application to a maximum of 1-4 dry MT/ha/yr (Schowanek et al, 2004). In conducting risk assessments, the European Commission assumes an application rate of 5 dry MT/ha/ yr (European Commission Joint Research Centre, 2003).…”

Section: Resultsmentioning

confidence: 99%

Organic chemicals in sewage sludges

Harrison

Oakes

Hysell

et al. 2006

Science of The Total Environment

433

227

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Sewage sludges are residues resulting from the treatment of wastewater released from various sources including homes, industries, medical facilities, street runoff and businesses. Sewage sludges contain nutrients and organic matter that can provide soil benefits and are widely used as soil amendments. They also, however, contain contaminants including metals, pathogens, and organic pollutants. Although current regulations require pathogen reduction and periodic monitoring for some metals prior to land application, there is no requirement to test sewage sludges for the presence of organic chemicals in the U. S. To help fill the gaps in knowledge regarding the presence and concentration of organic chemicals in sewage sludges, the peer-reviewed literature and official governmental reports were examined. Data were found for 516 organic compounds which were grouped into 15 classes. Concentrations were compared to EPA risk-based soil screening limits (SSLs) where available. For 6 of the 15 classes of chemicals identified, there were no SSLs. For the 79 reported chemicals which had SSLs, the maximum reported concentration of 86% exceeded at least one SSL. Eighty-three percent of the 516 chemicals were not on the EPA established list of priority pollutants and 80% were not on the EPA's list of target compounds. Thus analyses targeting these lists will detect only a small fraction of the organic chemicals in sludges. Analysis of the reported data shows that more data has been collected for certain chemical classes such as pesticides, PAHs and PCBs than for others that may pose greater risk such as nitrosamines. The concentration in soil resulting from land application of sludge will be a function of initial concentration in the sludge and soil, the rate of application, management practices and losses. Even for chemicals that degrade readily, if present in high concentrations and applied repeatedly, the soil concentrations may be significantly elevated. The results of this work reinforce the need for a survey of organic chemical contaminants in sewage sludges and for further assessment of the risks they pose.

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Section: Resultsmentioning

confidence: 99%

Organic chemicals in sewage sludges

Harrison

Oakes

Hysell

et al. 2006

Science of The Total Environment

433

227

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“…However, the recycling of such waste also causes negative effects on the ecosystem [3] due to the presence of heavy metal ions, [4] persistent organic pollutants [5] or even pharmaceuticals [6,7] in the final sewage product. For this reason, the Swiss Federal Government banned the use of sludge as a fertilizer in order to prevent any risk of irreversible damage to the soil and hence to the population.…”

mentioning

confidence: 99%

Thermal Runaway of Dried Sewage Sludge Granules in Storage Tanks

Poffet¹,

Käser²,

Jenny³

2008

Chimia

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Elimination of the sewage sludge from urban wastewater occurs exclusively by incineration in Switzerland, because recycling as fertilizer in agriculture has been banned since October 2006. Tw o options exist for elimination, either thermal elimination of a thickened sludge in a household waste incineration plant, or drying of the thickened sludge to yield a granular material fit for storage and transport. The high organic content of this material makes it a valuable alternative fuel for the cement industry. This elimination route is hampered, however, by the tendency of this material to self-heating and occasional thermal runaway resulting in fire. This research project deals with the investigation of the characteristics of these dried sewage sludge granules and the possible reasons for the observed self-heating phenomenon. It was found that a cascade of reactions and a series of circumstances are responsible for the thermal runaway, where each of them isolated would not lead to an event. Mainly responsible for triggering the initial temperature raise is the oxidation of Fe(II) compounds, added to the wastewater as FeClSO 4 for phosphate precipitation, and present in this lower oxidation state due to the reducing conditions in the digesters. Sulfate reduction to sulfide by sulfate-reducing bacteria (SRB) presents an additional source of latent heat in the final product once brought in contact with air as demonstrated by the observed formation of the high temperature allotrope γ -sulfur.

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“…The use of a battery of biotests, representing differences in sensitivity of test organisms from various trophic levels is recommended to prevent this situation. Therefore it is important to identify potential toxins and understand the magnitude of their impact on different terrestrial and aquatic ecosystems (Schowanek et al, 2004) …”

Section: Environmental Toxicologymentioning

confidence: 99%