Technology 2005: 2nd Joint Specialty Conference for Sustainable Management of Water Quality Systems for the 21st Century: Development of New Technologies to Suppress Leachate of Heavy Metals from Sewage Sludge Incineration Ash

Several aspects of using ashes from sewage sludge incineration in the brick and tile industry have been examined. After discussing the item of ash production in Germany, the impact of different wastewater treatment methods is described; for instance, the use of precipitation agents containing iron will considerably influence the ash quality. Depending on their respective chemical composition, different ashes have different effects on the ceramic qualities of the bricks made of clay blended with ashes. These effects will be shown in regard to the major ceramic parameters. Similarly, the quality of the ashes also influences the elution behaviour and the mineral fixation of heavy metals.

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Sequenced Bioleaching and Bioaccumulation of Phosphorus from Sludge Combustion – A New Way of Resource Reclaiming

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.71-73.625 ◽

2009 ◽

Vol 71-73 ◽

pp. 625-628 ◽

Cited By ~ 8

Author(s):

Jennifer Zimmermann ◽

Wolgang Dott

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Toxic Metals ◽

Available Phosphorus ◽

Phosphorus Leaching ◽

Digested Sludge ◽

Sludge Incineration ◽

P Accumulation ◽

Leaching Experiments ◽

P Recovery

The recovery of phosphorus from sewage sludge incineration ash as well as the separation of heavy metals from ash was investigated by using the biotechnological process of bioleaching and bioaccumulation of released phosphorus by newly developed population of bioleaching bacteria, Acidithiobacillus sp. strains, and polyphosphate (poly-P) accumulating bacteria, the AEDS-population (Acidithiobacillus sp. enriched digested sludge). The biologically performed solubilization of phosphorus from sewage sludge incineration ash is accompanied by the release of toxic metals. Therefore a combined process to separate phosphorus from heavy metals by achieving a plant available phosphorus-enriched product and a metal depleted ash was designed. Leaching experiments were conducted in laboratory scaled leaching reactor containing a bacterial stock culture of Acidithiobacillus sp.. Next step was the enhancement of P-recovery in combining bioleaching with simultaneous bio-P-accumulation by AEDS-population. The uptake of phosphorus in biomass reaches up to 66 % of the mobilized phosphorus by bioleaching. The combined biologically performed technology of phosphorus leaching and separation from toxic metals by simultaneous bioaccumulation developed in this study is a promising process for economical and ecological recovery of phosphorus from waste solids.

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Assessment of changes in the water quality along the length of the Siverskyi Donets river at the beginning of the 21st century

Ukrainian hydrometeorological journal ◽

10.31481/uhmj.23.2019.06 ◽

2019 ◽

pp. 54-68

Author(s):

N. S. Loboda ◽

О. V. Smalii ◽

І. V. Katynska ◽

О. M. Kotovich

Keyword(s):

Water Pollution ◽

Heavy Metals ◽

Water Quality ◽

21St Century ◽

Pollution Index ◽

Organic Substances ◽

Water Pollution Index ◽

Main River ◽

Water State ◽

Biogenic And Organic Substances

The relevance of the problem consists in the need to achieve a "good status" of water in the rivers of Ukraine according to the objectives of the Water Framework Directive. The aim of the work is to identify the main trends of water quality changes over time and along the length of Siverskyi Donets River based on data of the hydrochemical observations for the period from 1985 to 2015 inclusive. To establish the water quality we used integral assessments based on hydrochemical indicators such as pollution coefficient, water pollution index, generalized index of water state in accordance with the water quality standards for fishery. The article shows that use of mandatory (priority) chemical indicators in the calculations of the pollution coefficient and the water pollution index does not reflect a real degree of water pollution, since it does not take into account a significant amount of pollutants. It was discovered that major pollutants in the main river include suspended substances, chromium, nitrite nitrogen, phenols, sulfates. For the right-bank tributaries of Siversky Donets (illustrated by the example of the Kryvyi Torets River) originating from Donetsk Upland heavy metals (chromium, copper, zinc) pollution is typical. The degree of pollution based on the coefficient of pollution for average multi-year period is deemed as catastrophic, and based on the index of water pollution it is labelled with IV (contaminated) and V (very contaminated) quality classes indicating a violation of the ecosystem stability. Based on the generalized index, the water is also classified as "contaminated". The calculations based on various integral indicators of water quality revealed that pollution of the Siversky Donets River increases downstream. This is due to growing anthropogenic impact (municipal and industrial waters of large cities, discharge of mine and open pit waters into surface waterways, withdrawal of the runoff for its redirection to canals and water conduits, presence of diffuse sources of pollution by biogenic and organic substances). The beginning of the 21st century saw a trend towards improvement established in the chronological course of integral indicators of water quality which was associated with decrease production volumes. According to the generalized index of water state the water quality of the main river gradually changes from “contaminated” and “very contaminated” to “moderately contaminated”, but contamination by heavy metals, biogenic and organic substances remains high.

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Is Biochar from the Torrefaction of Sewage Sludge Hazardous Waste?

Materials ◽

10.3390/ma13163544 ◽

2020 ◽

Vol 13 (16) ◽

pp. 3544

Author(s):

Andrzej Białowiec ◽

Jakub Pulka ◽

Marzena Styczyńska ◽

Jacek A. Koziel ◽

Joanna Kalka ◽

...

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Hazardous Waste ◽

Process Parameters ◽

Sustainable Management ◽

Threshold Value ◽

Process Time ◽

Future Research ◽

Site Specific ◽

Standard Tests

Improved technologies are needed for sustainable management of sewage sludge (SS). The torrefaction (also known as biomass “roasting”) is considered a pretreatment of SS before use in agriculture. However, it is not known whether the torrefaction has the potential to decrease heavy metals’ (HMs) leachability and the SS toxicity. Thus, the aim of the study was to evaluate the influences of the SS torrefaction parameters (temperature and process time) on HM contents in biochar, HM leachability, and biochar toxicity, and compare them with raw SS. The experiments were designed in 18 combinations (six temperatures, 200, 220, 240, 260, 280, and 300 °C; and three process times—20, 40, 60 min). Standard tests were used to determine HMs content, leachability, and toxicity. Results indicated that the torrefaction did not increase (p < 0.05) the HM content in comparison to the raw SS. The leachability of Zn, Ni, Cu, Cr, and Mn from SS biochars was similar to raw SS. However, the degree of leachability varied significantly (p < 0.05) from as low as 0.1% for Cu to high as 16.7% for Cd. The leachability of Cd (<16.7%) and Pb (<11.9%) from biochars was higher than from raw SS (<6.1% and <2.4%, respectively). The leachability of Cd from SS biochar, in five torrefaction combinations, was higher than the threshold value for hazardous waste. It is recommended that site-specific decisions are made for torrefaction of SS with respect to its HM content, as the resulting biochar could be considered as hazardous waste, depending on the feedstock. Moreover, the biochar produced under the whole range of temperatures during 20 min retention time significantly (p < 0.05) increased the Daphnia magna Straus mobility inhibition by up to 100% in comparison to the biochar obtained during 40 and 60 min torrefaction. Taking into account the increased leachability of specific HMs and D. magna Straus mobility inhibition, biochar should be considered a potentially hazardous material. Future research should focus on biochar dosage as a fertilizer in relation to its toxicity. Additional research is warranted to focus on the optimization of SS torrefaction process parameters affecting the toxicity.

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