Influence of corn straw on distribution and migration of nitrogen and heavy metals during microwave-assisted pyrolysis of municipal sewage sludge

2021 ◽  
pp. 152303
Author(s):  
Yingwen Zhang ◽  
Chunbao Zhou ◽  
Zeyu Deng ◽  
Xueguang Li ◽  
Yang Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Corn Straw ◽  
Microwave Assisted ◽  
And Migration

Decontamination of Heavy Metals From Municipal Sewage Sludge (MSS) by Electrokinetic Remediation

2019 ◽  
Author(s):  
A. Ribeiro ◽  
J. Araújo ◽  
A. Mota ◽  
R. Campos ◽  
C. Vilarinho ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Operation Time ◽  
Electrokinetic Remediation ◽  
Permeable Reactive Barrier ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Reactive Barrier

Abstract A large quantity of sludges resulting from the treatment of MWWTP (Municipal Wastewater Treatment Plant) effluent is generated annually following the increase of population density and acceleration of urbanization. Sludge production in Europe has been predicted by around 12 million tons in 2020. As a solid waste, appropriate disposal of Municipal Sewage Sludge (MSS) has been taken seriously due to its larger volume and toxic substances such as heavy metals. Electrokinetic remediation has more advantages in heavy metals uptake compared to other technologies, due to the ability to treat soils in-situ and to remove heavy metals from soils. In this work, it was studied the remediation of MSS by the electrokinetic remediation coupled with activated carbon (AC) as a permeable reactive barrier (PRB). It was applied an electric current of 3 V cm−1 and it was used an AC/sludge ratio of 30 g kg−1 of contaminated sludge for the preparation of the PRB. In each trial, the evolution of cadmium (Cd), lead (Pb), copper (Cu), chromium (Cr), nickel (Ni) and zinc (Zn) removal from the sludge were evaluated. Results proved that this process is perfectly suited for the removal of chromium, nickel and zinc metals from the sludge. At the end of the operation time, it was achieved a maximum removal rate of 56% for chromium, 73% for nickel and 99% for zinc, with initial concentrations of 2790 mg kg−1, 2840 mg kg−1, and 94200 mg kg−1, respectively. Based on these results, it was proved the technical viability of the proposed technology (electrokinetic with AC as a permeable reactive barrier) to treat municipal sewage sludges.

scholarly journals Heavy metals accumulation from sewage sludge in the Nile tilapia Oreochromis niloticus (Trewavas, 1983) during a sludge-earthworm-fish short-term cycling

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Nahid A.A. Siddig ◽  
Asma A. Ahmed ◽  
Sarra A.M. Saad ◽  
Faisal Hammad Mekky Koua
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Environmental Protection Agency ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Short Term ◽  
Treated Soil ◽  
Nile Tilapia Oreochromis Niloticus

Municipal sewage sludge from wastewater treatment is an important nutritional source for sustainable agriculture. Here, we report on the assessment of the accumulation of heavy metals in Nile tilapia Oreochromis niloticus (Trewavas 1983) fed on earthworms Eisenia fetida reared on soil treated with different concentrations of sewage sludge (25% and 100%) during sludge-earthworm-fish short-term cycling. In this short-term cycling the Nile tilapia collected from the White Nile were chosen as final consumers, whereas the earthworms reared on loam soil mixed with different ratios of sludge were used as a feed for the final consumers. Our results indicate that the concentrations of Cd2+, Cr2+, Pb2+ and Zn2+ in the sludge treated soil are proportional to the sludge content in the soil. Importantly, the accumulation of these heavy metals was significantly low in the earthworms and the Nile tilapia in comparison with the treated soil and that these concentrations in the Nile tilapia were below the international limits recommended by the US Environmental Protection Agency (2014). Moreover, the growth and overall flesh quality of the fish were improved as indicated by the growth increase up to 146% when fed on earthworm reared in 100% sludge. Additionally, our physicochemical properties (i.e. pH, soil moisture, electric conductivity and organic matters) evaluation on the soil indicates an improvement of the soil quality when mixed with sewage sludge. These results suggest a sustainable application of sewage sludge in fish culture owing to its high nutritional values, low cost, and low risk of hazardous heavy metals when using primary consumers with heavy metals bioaccumulation capability such as E. fetida.

Effect of pH on metal solubilization from sewage sludge: a neural-net-based approach

1994 ◽  
Vol 21 (5) ◽  
pp. 728-735 ◽  
Author(s):  
Y. G. Du ◽  
T. R. Sreekrishnan ◽  
R. D. Tyagi ◽  
Peter G. C. Campbell
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Neural Net ◽  
Metals Removal ◽  
Complex Biological Process ◽  
System Temperature ◽  
Microbial Leaching ◽  
Metal Solubilization

Microbial leaching for heavy metals removal from municipal sewage sludge is a complex biological process. The ultimate metal solubilization achieved depends on the type of sludge involved (nondigested, aerobically digested or anaerobically digested sludge), the decrease in sludge pH as a result of the leaching operation, and the concentration of metals initially present in the sludge. In addition, the system temperature exerts an indirect but strong influence by its effect on the bacterial growth and acid production process. A neural-net-based model was developed to predict the solubilization of six heavy metals, Cd, Cr, Cu, Ni, Pb, and Zn, from sewage sludge using the bioleaching process. The only input parameters required are the type of sludge, initial metal concentrations in the sludge, and the sludge pH. The model yielded satisfactory predictions of metal solubilization when tested with a number of actual experimental data. Key words: heavy metals, microbial leaching, modelling, neural-net, sewage sludge.

Effects on Speciation of Ni & Cd in Sewage Sludge during Composting only and Co-Composting with Fly Ash Added

2012 ◽  
Vol 209-211 ◽  
pp. 1245-1252
Author(s):  
Zheng Zhong Zeng ◽  
Xiao Li Wang ◽  
Yu Pan ◽  
Zhong Ren Nan
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Sewage Sludge ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Unstable State ◽  
Land Utilization ◽  
Major Barrier ◽  
Exchangeable Fraction ◽  
State Content

The land use has become the international mainstream and the favorable direction to dispose the municipal sewage sludge in recent years. The heavy metals, however, are the major barrier that limit the land utilization. Batch aerobic composting experiments were conducted to investigate the effect of composting and co-composting with fly ash on the shape of the heavy metals (Ni & Cd) in sludge by using the sawdust to regulate the C/N ratio. Results have shown that co-composting with fly ash can significantly change Ni & Cd species distribution, leading unstable state content of Ni lower than composting only. However, the result is not as good as composting only in terms of Cd. At the same time the fly ash dosage equaling 14% of the dry sludge mass was the optimized quantity to guarantee the lowest exchangeable fraction amount of the two heavy metals.

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