Extensive green roofs, in which commercial compost is usually used as organic component, have great potential to mitigate some environmental problems caused by urbanization, but carry risks of ...nutrients leaching into downstream aquatic. Stabilized sludge (SS) from wastewater treatment plants could be potentially used as nutrient component for green roof, but the effects on effluent quality are uncertain. To investigate the problem, a pilot experiment was conducted under field conditions, the effluent quality of green roof using SS was compared with green roofs using peat soil and controlled release fertilizer. In the field experiment, the nutrient concentrations in effluent of the green roof using SS (TN, NO3−-N, NH4+-N and TP were 3.27 mg/L, 1.75 mg/L, 1.14 mg/L and 0.34 mg/L, respectively) were not significantly different from the green roofs using peat soil and controlled release fertilizer, and the chemical oxygen demand level (92 mg/L) was lower than the roofs using compost or commercial substrate. To reduce the environmental risks caused by the application of SS to green roofs, a laboratory test was carried out to analyze the effects of biochar and dual-substrate structure on nitrogen leaching. The results showed that both biochar and dual-substrate reduced nitrogen leaching, and nitrogen leaching from green roofs using SS was a combined effect of organic nitrogen mineralization during dry period and biological processes during wet period. A high temperature and low humidity environment which is common in green roofs reduced nitrate accumulation during dry period, and nitrate was transformed to other substances in gaseous form by denitrification, which tended to occur in long duration, low intensity rainfall events. The results suggest that the application of stabilized sludge to green roofs is feasible in area where average rain intensity is not high, preferably combined with amendment of biochar and a dual-substrate structure.
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•Applying stabilized sludge from WWTP to green roofs was feasible for the similar effluent quality to green roofs using common substrates.•Organic nitrogen mineralization was suppressed by low moisture and high-temperature environment.•Denitrification occurred in green roofs during a long duration, low intensity rainfall event
•The total desorbed amount of drugs is higher from anaerobic than aerobic sludge•Desorbed fractions can be used as a qualitative indicator of sludge/water mobility•Alkaline conditions increased the ...release of pharmaceuticals and illicit drugs•Desorbed fractions cannot be applied for terrestrial toxicity estimation
Pharmaceutical and illicit drug residues in sewage sludge may present important risks following direct application to agricultural soils, potentially resulting in uptake by plants. Leaching/desorption tests were performed on different types of stabilized sewage sludge originating from multiple treatment technologies in the Slovak Republic. Acid rain and base-rich condition of soil with different pH conditions were simulated to model the effect of widely varying pH (pH 2, 4, 7, 9, and 12) on the leaching/desorption of pharmaceuticals and illicit drugs. Twenty-nine of 93 target analytes were found above the limit of quantification in sludge or associated leachates. Total desorbed amounts of pharmaceuticals and illicit drugs ranged from 810 to 4000 µg/kg, and 110 to 3600 µg/kg of the dry mass of anaerobic and aerobic sludge, respectively. Desorbed fractions were calculated as these values are normalized to initial sludge concentration and, therefore, were more suitable for qualitative description of the behavior of individual compounds. Using principal component analysis, qualitative analysis of the desorbed fraction confirmed the differences among sludge types, pharmaceuticals, and desorption pH. Desorbed fractions could not be related to the octanol/water distribution coefficient. Desorbed fractions also did not reflect the expected ionization of studied molecules unless converted into their relative values. Generally, the lowest mobility was observed within the environmentally relevant pH range of 4-9, and high pH generally resulted in high desorption, especially in anaerobically stabilized sludges.
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Polycyclic aromatic hydrocarbons (PAHs) are widely present in the environment, causing increasing concern because of their impact on soil health, food safety and potential health risks. Four ...bioremediation strategies were examined to assess the dissipation of PAHs in agricultural soil amended with sewage sludge over a period of 120 days: soil-sludge natural attenuation (SS); phytoremediation using maize (Zea mays L.) (PSS); mycoremediation (MR) separately using three white-rot fungi (Pleurotus ostreatus, Phanerochaete chrysosporium and Irpex lacteus); and plant-assisted mycoremediation (PMR) using a combination of maize and fungi. In the time frame of the experiment, mycoremediation using P. chrysosporium (MR-PH) exhibited a significantly higher (P < 0.05) degradation of total PAHs compared to the SS and PSS treatments, achieving a degradation rate of 52 %. Both the SS and PSS treatments demonstrated a lower degradation rate of total PAHs, with removal rates of 18 % and 32 %, respectively. The PMR treatments showed the highest removal rates of total PAHs at the end of the study, with degradation rates of 48–60 %. In the shoots of maize, only low- and medium-molecular-weight PAHs were found in both the PSS and PMR treatments. The calculated translocation and bioconversion factors always showed values < 1. The analysed enzymatic activities were higher in the PMR treatments compared to other treatments, which can be positively related to the higher degradation of PAHs in the soil.
A revision of JIS A 5308 was officially announced in March 2019. This article explains the revision history and background of this standard, and the main revised content. In this revision, terms and ...definitions were newly defined and the item numbers were reviewed and the clause numbers were reordered. In addition, the use of sludge water using “stabilizer” for the purpose of environmental load reduction was newly defined. For high-strength concrete, the standard stipulates that the buyer can specify nominal strength in steps of 1（N/mm2）, and it adds 45 cm and 55 cm as new slump flow categories. Moreover, from the viewpoint of productivity improvement, concrete managed by slump flow was added to ordinary concrete, the slump categories were revised, the mixture plan format was changed, and the water-binder ratio description method was clarified.
The author has examined the application of different doses of stabilized-hydrated sewage sludge in two potato varieties in field conditions. Next to an unfertilized plot, he followed the growth, ...development and yield of varieties Agria and Aladin on soil treated with an amount of 50 t/ha and 30 t/ha of sludge from wastewater treatment plant in Subotica. He found that the highest yield was achieved at the variety Aladin (44.5 t/ha), when applying 30 t/ha of sludge. Agria produced 29.65 t/ha of tubers with the same amount of fertilizer. In both varieties the yields were higher on plots fertilized with 50 t/ha than on unfertilized soil. It was found that, in contrast to fertilizing with manure from 50 t/ha, half the amount of stabilized sludge produced similar, if not higher yields. In the future it will be possible to substitute or supplement manure with stabilized sludge under controlled conditions.
Based on orthogonal experimental design, the key solidification controlling technology of Solidified/Stabilized (S/S) sludge with high total organic content (TOC) by cement, lime and metakaolin was ...explored by macroscopic tests, chemical components measurements and microscopic analysis. The macroscopic tests show that, the permeability coefficient is mainly affected by initial water content and lime content, and the unconfined compression strength is mainly affected by cement content and lime content. The chemical components measurements show that, the solidification effect of S/S sludge with high TOC is controlled by organic matter consumption, and organic matter consumption is determined by the alkaline environment from the cement and lime hydration reactions, which is mainly affect by the initial water content and lime-metakaolin content ratio. The microscopic analysis results show that, lime consumes parts of organic matter while excess lime produces weak Ca(OH)2 crystal fluffy sheet structure, matakaolin produces pozzolanic reactions with cement and lime instead of soil particles, and consumes the weak Ca(OH)2 crystal fluffy sheet structure produced by superfluous lime. The research has confirmed key controlling points of S/S sludge in case of high TOC, which will provide theoretical guidance and technical support for S/S sludge promotion with high TOC.
Sewage sludge samples representing different stages during waste water and sewage sludge treatment were collected at four Austrian municipal waste water treatment plants. Changes of sludge ...composition are reflected by a specific infrared spectroscopic pattern. Anaerobically digested sludge was subjected to aeration in lab-scale reactors in order to find out if post-aeration after anaerobic digestion provides enhanced organic matter degradation and stabilization. Spectral data were evaluated by means of multivariate statistics. Similar spectral characteristics of sludge degradation stages were visualized by principal component analysis. The effect of additional aerobic treatment of anaerobically stabilized sludge was revealed by discriminant analysis that distinguishes additionally aerated sludge from all the other degradation stages of sludge because of changes in the spectral pattern by increasing stabilization. Based on partial least squares regression (PLSR) a correlation coefficient of
R
2
=
0.91 was found between spectral characteristics and the chemical oxygen demand (COD).
Abstract
Subinhibitory concentrations of antibiotics and biocides in wastewaters and sewage sludge have a great impact on the development of antibiotic resistance and its spread among bacteria. The ...aim of this work was to determine the occurrence of coliform bacteria and enterococci resistant to biocide triclosan in samples of sewage sludge. Subsequently, isolated strains of coliform bacteria were identified and characterized in terms of their antibiotic susceptibility and ability to form a biofilm. Occurrence of the studied bacteria was monitored in three samples of stabilized sludge from three different wastewater treatment plants (Vrakuňa, Petržalka, and Senec). The number of triclosan-resistant coliforms was the highest in the sludge sample from the wastewater treatment plant in Senec and the lowest in the sludge sample from the wastewater treatment plant in Petržalka. Triclosan-resistant
Enterococcus
spp. were not found in any sample of stabilized sludge. Most isolates were identified as
Citrobacter freundii
and
Serratia
spp. Triclosan-resistant isolates showed also resistance to antibiotics and the majority of them were strong biofilm producers.
2019年3月に改正公示されたJIS A ...5308について，改正の経緯とその背景，主な改正事項を解説する。今回の改正では，新たに用語及び定義を規定するとともに箇条番号の見直しを行った。また，環境負荷の低減として，“安定剤”を用いたスラッジ水の利用方法を新たに規定した。高強度コンクリートについては，呼び強度を1（N/mm2）間隔で購入者が指定できることを規定するとともに，スランプフローの区分に45cm，55cmを追加した。また生産性向上の観点からは，普通コンクリートにスランプフローで管理するコンクリートの追加とスランプ区分の見直し，配合計画書の様式の変更と水結合材比の記入方法の明確化を行った。
Lime-stabilized sewage sludge and composted poultry manure, at a rate of
250
m
3
ha
−1
each, and slow-release N fertilizer (Scott's Osmocote) at 100, 200 and
300
kg
N
ha
−1
, were applied to plots of ...willow biomass crops during the first season of a three-year growth cycle. Stem biomass production was measured annually and soil chemical characteristics were assessed at the end of the growth cycle. Average annual stem biomass production was 8–
11
Mg
ha
−1
in slow-release N fertilized plots corresponding to a yield increase of 7–33% relative to control plots. In organically amended plots, annual stem biomass production increased by 30–38% relative to control plots. The study suggests that organically amended willows grew at a slightly faster rate than slow-release N fertilized willows. Statistically, the relationship between slow-release N application rate and stem biomass production was not highly significant; applications of slow-release N in excess of
100
kg
N
ha
−1
provided no additional yield benefits. Differences in soil characteristics were most strongly expressed in surface soil. The pH at 0–
10
cm
depth was 1 and 2 units higher on lime-stabilized sludge and composted poultry manure plots, respectively. Concentrations of soil K, P and Mg were dramatically higher in the composted poultry manure soils. The highest soil organic matter and N levels were observed in the surface horizons of organically amended soils. Utilization of organic residuals increases biomass production, provides beneficial use for wastes, reducing production costs and contributing to the sustainability of biomass production systems.
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