Leaching of Phosphorus From Ashes of Co-Combustion of Sewage Sludge and Wood

Author(s):  
Anita Pettersson ◽  
Bengt-A˚ke Andersson ◽  
Britt-Marie Steenari ◽  
Lars-Erik A˚mand ◽  
Bo Leckner

Municipal sewage sludge has a high concentration of phosphorus, which should be recovered because phosphorus is a limited natural resource. In this work, sewage sludge was co-fired with wood in a FBC boiler. The aim of the investigating was to study the solubility of phosphorus in the ashes, by leaching as an alternative to the phosphorous recovery method of using the ashes directly on farmlands. The fly ashes from the boiler’s secondary cyclone and bag filter were leached at various pH-values and the release of phosphorus was measured. Only acidic leaching was applied. The ashes precipitated with Al2(SO4)3 released nearly all phosphorus at a pH-value of 1, whereas the ashes precipitated with Fe2(SO4)3 did not release all phosphorus even at the very low pH of 0.5. The concentrations of phosphorous in the leachate must be compared with liquid phosphorus sources such as human urine or liquid animal manure used as fertilisers. This may result in that the leachate has to be processed further. A continuation of the work to investigate to what extent the leachate is contaminated with toxic trace elements is necessary.

2019 ◽  
pp. 115-124
Author(s):  
Piotr Kowalik ◽  
Ewa Wojciechowska

Utilization of sewage sludge is becoming one of the biggest environmental problems.One of the possible solutions is application of sludge to soil amendment. Sludge is a goodnatural fertilizer due to high concentration of organic carbon and nutrient elements (N, P).On the contrary, sewage sludge also contains heavy metals and may be contaminatedwith enteric parasites. Thus application of sludge to land could result in contamination ofsurface and ground waters and including trace metals in the food chains due tocontamination of plants grown on sludge amended soils. Hence land application of sludgeought to be carefully monitored and follow stringent regulations, which are often difficultto fulfil. However, if sludge is applied to reclamation of degraded post-industrial lands,waste deposition sites, landfills and formation of soil-like surface layer on soil-lessgrounds, the restrictions are not so stringent and easier to fulfil than in cases when cropsare grown on sludge amended soils.In the article reclamation of a phosphogypsum deposition site in Wislinka near Gdanskusing sewage sludge from a municipal wastewater treatment plant (WWTP) is discussed.Phosphogypsum deposit in Wislinka for many years has been one of the biggestenvironmental problems of the region, causing permanent complainants from localcommunities. Reclamation of the deposition site started in 1999 and has been continuedup till now. Covering of the slopes with a layer of sludge reduces dangerous wind erosionof dust and promotes plants succession.


2004 ◽  
Vol 50 (5) ◽  
pp. 133-140 ◽  
Author(s):  
P. Ivashechkin ◽  
P.F.-X. Corvini ◽  
M. Dohmann

Agricultural application of municipal sewage sludge has been emotionally discussed in the last decades, because the latter contains endocrine disrupting chemicals (EDCs) and other organic micro-pollutants with unknown fate and risk potential. Bisphenol A (BPA) was chosen as a model substance to investigate the influence of sludge conditioning on the end-concentration of EDCs in sludge. Adsorption studies with radioactive-labelled BPA showed that more than 75% BPA in anaerobically digested sludge is bound to solids (log Kd = 2.09-2.30; log Koc = 2.72-3.11). Sludge conditioning with polymer or iron (III) chloride alone had no influence on the adsorption of BPA. After conditioning with iron (III) chloride and calcium hydroxide desorption of BPA took place. Apparently, it occurred due to the deprotonation of BPA (pKa = 10.3) as the pH-value reached 12.4 during the process. The same behaviour is expected for other phenolic EDCs with similar pKa (nonylphenol, 17β-estradiol, estron, estriol, 17α-ethinylestradiol). This study shows high affinity of BPA to the anaerobically digested sludge and importance of conditioning in the elimination of EDCs during the sludge treatment. Addition of polymer is favourable in the case of sludge incineration. Conditioning with iron (III) chloride and calcium hydroxide shows advantages for the use of sludge as fertiliser.


2020 ◽  
Vol 10 (10) ◽  
pp. 3445 ◽  
Author(s):  
Roberta Ferrentino ◽  
Riccardo Ceccato ◽  
Valentina Marchetti ◽  
Gianni Andreottola ◽  
Luca Fiori

Municipal sewage sludge was subjected to a hydrothermal carbonization (HTC) process for developing a hydrochar with high adsorption capacity for water remediation in terms of dye removal. Three hydrochars were produced from municipal sewage sludge by performing HTC at 190, 220 and 250 °C, with a 3 h reaction time. Moreover, a portion of each hydrochar was subjected to a post-treatment with KOH in order to increase the adsorption capacity. Physicochemical properties of sludge samples, raw hydrochars and KOH-modified hydrochars were measured and batch adsorption studies were performed using methylene blue (MB) as a reference dye. Data revealed that both raw and modified hydrochars reached good MB removal efficiency for solutions with low MB concentrations; on the contrary, MB in high concentration solutions was efficiently removed only by modified hydrochars. Interestingly, the KOH treatment greatly improved the MB adsorption rate; the modified hydrochars were capable of capturing above 95% of the initial MB amount in less than 15 min. The physicochemical characterization indicates that alkali modification caused a change in the hydrochar surface making it more chemically homogeneous, which is particularly evident for the 250 °C hydrochar. Thus, the adsorption process can be regarded as a complex result of various phenomena, including physi- and chemi-sorption, acid–base and redox equilibria.


Agronomie ◽  
2001 ◽  
Vol 21 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Giovanni Gigliotti ◽  
Pier Lodovico Giusquiani ◽  
Daniela Businelli

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3106
Author(s):  
Tomasz Kalak ◽  
Kinga Marciszewicz ◽  
Joanna Piepiórka-Stepuk

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.


2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.


2011 ◽  
Vol 383-390 ◽  
pp. 3799-3804
Author(s):  
Xiao Xu Fan ◽  
Lei Zhe Chu ◽  
Li Guo Yang

The fuel characteristics of municipal sewage sludge are suitable for dual fluidized bed(DFB) gasification, which can get middle calorific value gas through volatile pyrolysis, and reduce volume through char combustion. The hot test results of municipal sewage sludge on DFB rig were showen that the temperature distribution along combustor heigh is uniform, and the carbon content of fly ash is about 2~3%. In the experiment, with the increase of gasifier temperatrue, the more volatile of the sewage sludge was pyrolyzed. When the temperature of the gasifier reached 800°C, the calorific value of gas was 6.9MJ/Nm3; the emissions of SO2, NOx and HCl were appropriate to the standard. The leaching toxicity of heavy metal of the fly ash was lower than the discharge standard.


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