The impact of nanoparticles on aerobic degradation of municipal solid waste

2017 ◽  
Vol 35 (4) ◽  
pp. 426-436 ◽  
Author(s):  
Senem Yazici Guvenc ◽  
Burcu Alan ◽  
Elanur Adar ◽  
Mehmet Sinan Bilgili

The amount of nanoparticles released from industrial and consumer products has increased rapidly in the last decade. These products may enter landfills directly or indirectly after the end of their useful life. In order to determine the impact of TiO2 and Ag nanoparticles on aerobic landfilling processes, municipal solid waste was loaded to three pilot-scale aerobic landfill bioreactors (80 cm diameter and 350 cm height) and exposed to TiO2 (AT) and Ag (AA) nanoparticles at total concentrations of 100 mg kg−1 of solid waste. Aerobic landfill bioreactors were operated under the conditions about 0.03 L min−1 kg−1 aeration rate for 250 days, during which the leachate, solid waste, and gas characteristics were measured. The results indicate that there was no significant difference in the leachate characteristics, gas constituents, solid quality parameters, and temperature variations, which are the most important indicators of landfill operations, and overall aerobic degradation performance between the reactors containing TiO2 and Ag nanoparticles, and control (AC) reactor. The data also indicate that the pH levels, ionic strength, and the complex formation capacity of nanoparticles with Cl− ions can reduce the toxicity effects of nanoparticles on aerobic degradation processes. The results suggest that TiO2 and Ag nanoparticles at concentrations of 100 mg kg−1 of solid waste do not have significant impacts on aerobic biological processes and waste management systems.

2020 ◽  
Vol 9 (1) ◽  
pp. 211-217

The high moisture content of municipal solid waste yields a lower energy content of solid fuel that affects the thermal conversion efficiency. Biodrying is an alternative drying method using bio-heat generated by microbial metabolism to reduce the moisture content of municipal solid waste. This research was conducted in three pilot-scale biodrying reactors, two under greenhouse conditions compared with one conventional non-greenhouse condition. Two bunkers with greenhouse cladding were connected with aerators, and airflow rates were set at 0.4 and 0.6 m3/(kgwaste·day), respectively. Meanwhile, a passive aeration method was applied to the non-greenhouse bunker. This study aims to investigate the effect of the greenhouse condition on the biodrying process and assess the performance of the drying process through different operating conditions. The result shows that the greenhouse mainly affects the air temperature rise in the reactor. The aeration rate is positively correlated with weight reduction (r = 0.93). At 0.6 m3/(kgwaste·day) airflow rate, the treatment can reach a moisture content less than 30% on average within ten days, while at 0.4 m3/(kgwaste·day) airflow rate, it takes 15 days to reduce the moisture content to less than 30%. Biodrying under the greenhouse condition with active aeration potentially achieves desirable moisture content reduction and heating value increase more efficiently than the common biodrying. However, the airflow rate is a crucial factor in determining the suitable drying time in biodrying under the greenhouse condition.


2021 ◽  
Vol 13 (13) ◽  
pp. 7115
Author(s):  
Mostafa Kazemi ◽  
Luc Courard ◽  
Julien Hubert

A green roof is composed of a substrate and drainage layers which are fixed on insulation material and roof structure. The global heat resistance (Rc) within a green roof is affected by the humidity content of the substrate layer in which the coarse recycled materials can be used. Moreover, the utilization of recycled coarse aggregates such as incinerated municipal solid waste aggregate (IMSWA) for the drainage layer would be a promising solution, increasing the recycling of secondary resources and saving natural resources. Therefore, this paper aims to investigate the heat transfer across green roof systems with a drainage layer of IMSWA and a substrate layer including recycled tiles and bricks in wet and dry states according to ISO-conversion method. Based on the results, water easily flows through the IMSWAs with a size of 7 mm. Meanwhile, the Rc-value of the green roof system with the dry substrate (1.26 m2 K/W) was 1.7 times more than that of the green roof system with the unsaturated substrate (0.735 m2 K/W). This means that the presence of air-spaces in the dry substrate provided more heat resistance, positively contributing to heat transfer decrease, which is also dependent on the drainage effect of IMSWA. In addition, the Rc-value of the dry substrate layer was about twice that of IMSWA as the drainage layer. No significant difference was observed between the Rc-values of the unsaturated substrate layer and the IMSWA layer.


2012 ◽  
Vol 14 (4) ◽  
pp. 371-378 ◽  
Author(s):  
M. Delgado-Rodríguez ◽  
M. Ruiz-Montoya ◽  
I. Giraldez ◽  
R. López ◽  
E. Madejón ◽  
...  

Economies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 54 ◽  
Author(s):  
Hanke Ndau ◽  
Elizabeth Tilley

Insufficient staff, inappropriate collection vehicles, limited operating budgets and growing, hard to reach populations mean that solid waste management remains limited in most developing countries; Malawi is no exception. We estimated the willingness to pay (WTP) for two hypothetical solid waste collection services. Additionally, we tested the impact of the WTP question positioning relative to environmental perceptions on respondents’ WTP. The first scenario involved a five minute walk to a disposal facility; the second scenario involved a 30 min walk. Additionally, the order of the question was randomized within the questionnaire. A WTP value of K1780 was found for the five minute walk scenario when the question was placed first, and K2138 when placed after revealing the respondent’s perceptions on the environment. In the 30 min walk scenario, WTP was K945 when placed first and K1139 when placed after revealing the respondent’s perceptions on the environment. The estimated values indicate that there is both a willingness to pay for solid waste services and that there are at least two options that would be acceptable to the community; a pilot scale implementation would be required to validate the hypothetical values, especially given the dependency on problem framing. Community financing should be considered as a sustainable approach to solid waste management in underserved areas.


1993 ◽  
Vol 28 (2) ◽  
pp. 27-34 ◽  
Author(s):  
G. Boari ◽  
I. M. Mancini ◽  
E. Trulli

Sanitary landfills of municipal solid waste (MSW) might be used to reduce the storage volume required at plants giving year-round treatment of olive oil mill effluent (OME). A landfill in the methanogenic stage could act as an anaerobic filter and reduce the pollutional load of the OME while also acting as a temporary storage tank. In the present work, a lysimeter in pilot scale was used to simulate a cell of a sanitary landfill. It was filled with MSW screened by a 80 mm mesh sieve mixed to municipal sludge. Results show that when OME was spread on the top of the lysimeter at a loading rate not exceeding 0.4 kgCOD/d/m3 of reactor steady methanogenic activity was maintained in the layers of refuse and a 70% removal of COD was obtained in the OME leachate collected. Higher loading rates reduced methanogenic activity and COD removal efficiency. Nevertheless, the OME collected from the bottom of the landfill was more easily treated by anaerobic digestion than was the raw OME.


2009 ◽  
Vol 29 (1) ◽  
pp. 78-85 ◽  
Author(s):  
R. Valencia ◽  
W. van der Zon ◽  
H. Woelders ◽  
H.J. Lubberding ◽  
H.J. Gijzen

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