Fate and distribution of nutrients and heavy metals during hydrothermal carbonization of sewage sludge with implication to land application

2019 ◽  
Vol 225 ◽  
pp. 972-983 ◽  
Author(s):  
Liping Wang ◽  
Yuzhi Chang ◽  
Qifeng Liu
2016 ◽  
Vol 218 ◽  
pp. 183-188 ◽  
Author(s):  
Yunbo Zhai ◽  
Xiangmin Liu ◽  
Yun Zhu ◽  
Chuan Peng ◽  
Tengfei Wang ◽  
...  

2014 ◽  
Vol 878 ◽  
pp. 647-656 ◽  
Author(s):  
Liang Dai ◽  
Biao Lin Peng ◽  
Bi Gui Wei ◽  
Gui Ma

The application of sewage sludge on agricultural soils is a promising technical solution. Pot experiments were performed to study the effect of sewage sludge application on growth, physiology and accumulation of heavy metals in three kinds of wheat. The experimental results showed soil pH decreased significantly with the increase of the application of sewage sludge. The contents of Cu, Zn and Pb in the mixed soil did not exceed the Environmental quality standards for soils in China for Grade II (GB-1518-1995).Wheat obtained good growth activities after the application of sewage sludge, however, high land application of sewage sludge (the ratio of sludge in the mixed soil of dry weight was 20% and 25%) inhibited seed emergence and root length. The content of total chlorophyll in wheat increased with the increase of sewage sludge application first and reached a maximum, and then decreased with a further increase of sewage sludge. Compared with the control, the a/b value in chlorophyll showed trace change. The content of proline in wheat increased with the increase of sewage sludge in low doses of sewage sludge (5%, 10% and 15%), while there was no significant increase in the content in high land application of sewage sludge. The physiological metabolism of wheat will exhibit abnormality as the stress of pollutants from sludge exceeded the tolerance of wheat. The content of three kinds of heavy metals in wheat grain increased obviously with sludge application increasing, indicating an increasing trend, and had the phenomenon of exceeded the safety qualification of non-environmental pollution food in china at high doses of sewage sludge. Taking account of the effects of sewage sludge application on growth,physiology and accumulation of heavy metals in wheat, the doses of sludge in the mixed soil of dry weight should be lower than 15%.


2018 ◽  
Vol 12 (5) ◽  
pp. 27-34
Author(s):  
Mohsen Mohammadi Galangash ◽  
◽  
Mostafa Mahdavianpour ◽  
Samira Ghafouri Safa ◽  
◽  
...  

Background: Sewage treatment leads to the production of large amount of sludge, containing organic matter and nutrients and considering requirements for recycling could be used as fertilizer. The sludge may also contain various pollutants that pose serious harm to human health and the environment. This study aimed at characterizing the industrial sewage sludge and evaluating its capability as fertilizer with no or a minor pretreatment. Methods: The sludge’s organic matter and nutrient contents, heavy metals, organic and microbial contaminants were determined and compared to literature data and international guidelines. Results: The organic matter, nutrients, phosphorous, and exchangeable potassium contents of the sludge samples were significantly high as follows: 33.6 ± 2.85 %, 6.29 ± 0.16 %, 1.41± 0.01 % and 1.236 g/kg, respectively. The concentration of heavy metals was 94.3 ± 59.5 mg/kg. The concentration of heavy metals, organic contaminants, such as PCBs, BTEX, and PAHs, and microbial contents (coliforms & E. coli) were lower than those reported by other studies. Toluene concentration was high. Conclusions: All characteristics of the sludge samples, except for the toluene and microbial contaminations, were acceptable for its use as land fertilizer. Both toluene and microbial contaminants can be removed, using thermal conditioning as a pretreatment.


2013 ◽  
Vol 838-841 ◽  
pp. 2694-2700
Author(s):  
Liang Dai ◽  
Ya Mei Gao ◽  
Jun Ping Zhang

Through pot experiments,the effects of various sludge loadings (0,40,80,120,200,280 t·ha-1) on growth of maize and sewage sludge application on contents of heavy metals in the soil were studied using sewage sludge from An-ning Plant of Wastewater Treatment of Lanzhou City. The results showed land application of sewage sludge increased significantly the contents of PbCuZn in the soil. The contents of PbCuZn in the soil did not exceed the standard of Environmental quality standards for soils for Grade II (GB-1518-1995) in china. Maize obtained good growth activities after land application of sewage sludge,maize height and biomass were increased significantly and were better than the control. Land application of sewage sludge inhibited maize seedling emergence and maize root length,showing the effects of dose-effect relationship with sludge application increasing. Maize root length was restrained significantly by heavy metals in the soil, the effects of heavy metals in the soil on plant root system should be considered with land application of sewage sludge. The optimal land application of sewage sludge is 80-120 t·ha-1.


2002 ◽  
Vol 46 (9) ◽  
pp. 303-308 ◽  
Author(s):  
S.M. Zain ◽  
H. Basri ◽  
F. Suja' ◽  
O. Jaafar

Some of the major concerns when applying sewage sludge to land include the potential effect on pH and cation exchange capacity; the mobility and the accumulation of heavy metals in sludge treated soil; the potential of applying too much nutrients and the problems associated with odors and insects. The main objective of this study is to identify the effects of sewage sludge application on the physical and chemical properties of sludge treated soil. Sewage sludge was applied to soil at various rates ranging from 0 L/m2 to 341 L/m2. In order to simulate the natural environment, the study was carried out at a pilot treatment site (5.2 m × 6.7 m) in an open area, covered with transparent roofing material to allow natural sunlight to pass through. Simulated rain was applied by means of a sprinkler system. Data obtained from sludge treated soil showed that the pH values decreased when the application rates were increased and the application period prolonged. The effect of sewage sludge on cation exchange capacity was not so clear; the values obtained for every application rate of sewage sludge did not indicate any consistent behaviour. The mobility of heavy metals in soils treated with sludge were described by observing the changes in the concentration of the heavy metals. The study showed that Cd has the highest mobility in sludge treated soil followed by Cu, Cr, Zn, Ni and Pb.


Author(s):  
Shihe Li ◽  
Baihui Fang ◽  
Dongfang Wang ◽  
Xianqing Wang ◽  
Xiaobing Man ◽  
...  

In order to evaluate the environmental risk caused by land application of sewage sludge, leaching characteristics of heavy metals and plant nutrients in the sewage sludge immobilized by composite phosphorus-bearing materials were investigated. Their cumulative release characteristics were confirmed. Furthermore, the first-order kinetics equation, modified Elovich equation, double-constant equation, and parabolic equation were used to explore dynamic models of release. Results showed that sewage sludge addition significantly increased electricity conductivity (EC) in leachates, and the concentrations of heavy metals (Cu, Cr, Zn) and plant nutrients (N, P, K) were also obviously increased. The highest concentrations of Cu, Cr, and Zn in the leachates were all below the limit values of the fourth level in the Chinese national standard for groundwater quality (GB/T14848-2017). The immobilization of composite phosphorus-bearing materials reduced the release of Cu and Cr, while increased that of Zn. The fitting results of modified Elovich model and double-constant model were in good agreement with the leaching process of heavy metals and plant nutrients, indicating their release process in soil under simulated leaching conditions was not a simple first-order reaction, but a complex heterogeneous diffusion process controlled by multifactor.


2013 ◽  
Vol 37 (6) ◽  
pp. 512-520 ◽  
Author(s):  
Rodrigo Santos Moreira ◽  
Ronaldo Luiz Mincato ◽  
Breno Régis Santos

Sewage sludge is the solid residue obtained from urban sewage treatment plants. It is possible to use the sludge in a sustainable way as fertilizer and as soil conditioner due to its high levels of organic matter and nutrients. Besides pathogens and volatile organic compounds, the residue may also contain heavy metals which may accumulate and contaminate crops and the food chain. The aim of this study was evaluates the changes in the fertility of dystrophic Red Latosol and in the availability of heavy metals following application of sewage sludge. It was assessed whether organic matter supplied to the soil as large amounts of sewage sludge would decrease availability of heavy metals in the soil due to of insoluble compounds formation. From this, an experiment was carried out in polyethylene pots using lettuce plant for test. Sewage sludge were applied to the soil in concentrations equivalent to 60, 120 and 180 t ha-1, and a control without sludge, in four replicates, in a completely randomized design. The results show that sewage sludge led to an increase of organic matter contents, of the cation exchange capacity (CEC) and of nutrients found in the soil. It also improved plant growth up to a concentration of 120 t ha-1. Availability of heavy metals, however, was reduced in sludge concentrations starting with 120 t ha-1.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Meng Liu ◽  
Yufeng Duan ◽  
Kagiso Bikane ◽  
Liang Zhao

The migration and transformation behaviors of heavy metals (HMs), including Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb, during the hydrothermal carbonization (HTC) of sewage sludge (SS) were investigated. The immobilization of HMs during the combustion of solid residual (SR) produced from HTC of SS was also analyzed. With increasing HTC temperature and residence time, the majority of HMs (except As) accumulated in the SR. The residual rate of As in the SR decreased from 73.95% to 56.74% when the residence time was increased from 1h to 3h and reduced significantly from 73.95% to 37.48% when the temperature increased from 220°C to 280°C, implying that numerous arsenic compounds dissolved into liquid phase products. Although the HTC process has a positive influence on the transformation of HMs from weakly bound fractions to the more stable fractions, the exchangeable and reducible fractions of Mn, Zn, As, and Cd in the SR were still high. In addition, the leached amounts of Zn and As were high (14.61 and 6.16 mg/kg, respectively) and showed a high leaching risk to the environment. An increase in HTC temperature and residence time led to an increase of the residual rate of HMs in the combustion residual of SR, implying that the HTC process promotes the stabilization of HMs in the combustion process.


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