Results 1 - 10 of 726
Results 1 - 10 of 726. Search took: 0.023 seconds
|Sort by: date | relevance|
[en] Landfill leachate normally contains organic and inorganic pollutants in high concentrations. Electrochemical oxidation technique is an effective method to treat landfill leachate, have high efficiency in organic pollutants degradation and ammonia removal. In this study, a cost effective charcoal base metallic composite electrode to treat landfill leachate by electrochemical oxidation was fabricated. The effects of operational parameters such as supporting electrolyte, applied voltage and electrolysis time on the removal percentage of Color, COD, NH_3-N and total-P (PO_4"-"3) were carried out. The results obtained show that the removal percentage of Color, COD, NH_3-N and total- P (PO_4"-"3) are 70, 89, 73 and 80 % respectively. Under the optimum operating condition, sodium chloride concentration of 1.5 % (w/v), applied voltage of 10 V, operating time 180 min and C_6_0C"G_1_5Co_1_0"-PVC_1_5 electrode as an anode were used. (author)
[en] Highlights: • Pairing social and technical innovations improves organic collection programs. • Supportive infrastructure significantly increases household food waste diversion. • Norm communication increases separation behavior and reduces dropout. •Model predicting-fit best behavior-change tools is partially supported. • Norms are most effective on population perceiving low benefits and barriers. - Abstract: Cities around the world are under increasing political pressure to develop organics collection programs (OCP) to curb the flow of food waste into landfills, reduce the associated greenhouse gases, and generate compost or biogas. While OCPs tend to focus on infrastructure, they often overlook the linchpin role that household behavior change plays in the success of OCPs. The current research used a longitudinal field experiment (n=370) to test both the effectiveness of a new curbside OCP and new social innovations intended to stimulate pro-environmental changes in household behavior. The findings suggest greater participation levels occur by implementing both new supportive infrastructure (i.e., curbside carts and collection services), and innovations that target the social aspects of waste (i.e., communicating social norms of separation). The data also provide an opportunity to test new model for predicting the most efficacious behavior-change interventions based on population profiles. The results provide some support for the model; reducing barriers (i.e., curbside carts and collection) tends to help all population profiles, but norm communication increases participation more for the hypothesized profile than for other sub-groups.
[en] Aquatic or land-based plastic pollution has raised serious concerns for ecosystems, and especially human and animal health worldwide. A variety of legislative instruments were developed to control, reduce, and manage the usage of plastics in day-to-day life to minimize the adverse outcomes brought by sending these plastic to landfill. Existing legislation heavily embraces levies, bans, and voluntary efforts through “reduce and reuse campaigns.” Thus, the present review highlights the pros and cons of the existing legislation and its implementation. It also assesses the need for the improvement of plastic legislation to better consider environmental and human health impacts. The paper proposes new efficient management strategies to aid in the development of plastic legislation which prevents increase of plastic pollution worldwide, the potential challenges that would arise from its implementation, and the mechanisms for overcoming these challenges. The paper proposes a conventional management strategy based on the current plastic management and legislation. It aims to improve the feasibility and effectiveness of the implementation of future plastic policies.
[en] This report provides the results of the annual post-closure inspections conducted at the closed Corrective Action Units (CAUs) located on the Tonopah Test Range (TTR), Nevada. This report covers calendar year 2010 and includes inspection and repair activities completed at the following seven CAUs: (1) CAU 400: Bomblet Pit and Five Points Landfill (TTR); (2) CAU 407: Roller Coaster RadSafe Area (TTR); (3) CAU 424: Area 3 Landfill Complexes (TTR); (4) CAU 426: Cactus Spring Waste Trenches (TTR); (5) CAU 453: Area 9 UXO Landfill (TTR); (6) CAU 484: Surface Debris, Waste Sites, and Burn Area (TTR); and (7) CAU 487: Thunderwell Site (TTR).
[en] The cultivation of energy crops on landfills represents an important challenge for the near future, as the possibility to use devalued sites for energy production is very attractive. In this study, four scenarios have been assessed and compared with respect to a reference case defined for northern Italy. The scenarios were defined taking into consideration current energy crops issues. In particular, the first three scenarios were based on energy maximisation, phytotreatment ability, and environmental impact, respectively. The fourth scenario was a combination of these characteristics emphasised by the previous scenarios. A multi-criteria analysis, based on economic, energetic, and environmental aspects, was performed. From the analysis, the best scenario resulted to be the fourth, with its ability to pursue several objectives simultaneously and obtain the best score relatively to both environmental and energetic criteria. On the contrary, the economic criterion emerges as weak, as all the considered scenarios showed some limits from this point of view. Important indications for future designs can be derived. The decrease of leachate production due to the presence of energy crops on the top cover, which enhances evapotranspiration, represents a favourable but critical aspect in the definition of the results.
[en] A study to determine whether Radiological Impact Assessment (RIA) is needed for landfill disposal of treated sludge (slag) from oil and gas industries has been carried out. Radioactivity level of slag and soil samples have been measured using gamma spectrometry system and its Total Activity Concentration (TAC) has been calculated. It was found that TAC (inclusive background) was within the control limit set by the AELB for example, 3 Bq/g as stipulated in LEM/TEK 58 (AELB, 2009). Therefore, as a result from this study, RIA is not required and the allocated area can be used for the landfill disposal of treated sludge (slag).(author)
[en] For the understanding of contaminant transport and transformation through landfill liner soils, most models are proposed with one-dimensional solutions. However, for large-scale contamination analysis, the one-dimensional analytical equations are not valid owing to the restriction of contaminants moving in horizontal direction. Thus, semi-analytical solutions for two-dimensional transport and transformation of contaminants through soil media with the consideration of large-strain deformation have been developed. To achieve this, Gibson’s large-strain consolidation theory is applied to capture the deformation of soil media under loading, with self-weight effects being taken into account. Transport and transformation of dissolved or sorbed contaminates in fully saturated finite soil medias are captured by extending a well-developed advection-dispersion model in two-dimensional space. The proposed analytical solutions are validated through simulating the process of coupled transport-transformation process of contaminants and consolidation of a finite soil layer. Profiles of contaminant concentration for different cases have been compared and discussed. The resulting simulation shows that large-strain deformation would restrict the transport and transformation of contaminants significantly, in both horizontal and vertical directions. Parameter studies also indicate that, with the increasing depth of soil layer, the breakthrough time for contaminants increases dramatically; diffusion coefficients affect the two-dimensional distributions of contaminant concentration and fate of contaminant in layered soil significantly. The numerical findings of this study can provide proper suggestions for the design of landfill liners.
[en] This study investigates the hydraulic performance and the fouling characteristics of a bench-scale membrane sequencing batch reactor (MSBR), treating mature landfill leachate under various time-based operating conditions. The MSBR system operated initially under a high-flux condition (Period 1) which resulted in a rapid trans-membrane pressure (TMP) rise due to intense fouling. Following the characterization of Period 1 as super-critical, the system was subsequently operated under a near-critical condition (Period 2). The overall filtration resistance analysis showed that cake layer formation was the dominant fouling mechanism during Period 1, contributing to 85.5% of the total resistance. However, regarding the MSBR operation during Period 2, adsorption was found to also be a dominant fouling mechanism (Days 1 to 47), contributing to 29.1% of the total resistance. Additionally, the irregular total resistance variation, which was observed during the subsequent operation (Days 48 to 75), and the respective filtration resistance analysis suggested also the formation of an initial sludge cake layer on the membrane surface, contributing to the 47.7% of the total resistance.
[en] Highlights: ► Critical assessment of the main commercially available MSW gasifiers. ► Detailed discussion of the basic features of gasification process. ► Description of configurations of gasification-based waste-to-energy units. ► Environmental performance analysis, on the basis of independent sources data. - Abstract: The paper proposes a critical assessment of municipal solid waste gasification today, starting from basic aspects of the process (process types and steps, operating and performance parameters) and arriving to a comparative analysis of the reactors (fixed bed, fluidized bed, entrained bed, vertical shaft, moving grate furnace, rotary kiln, plasma reactor) as well as of the possible plant configurations (heat gasifier and power gasifier) and the environmental performances of the main commercially available gasifiers for municipal solid wastes. The analysis indicates that gasification is a technically viable option for the solid waste conversion, including residual waste from separate collection of municipal solid waste. It is able to meet existing emission limits and can have a remarkable effect on reduction of landfill disposal option.
[en] The characteristics of Durio Zibethinus seed starch (DSS) that is used for landfill leachate treatment was investigated in this study. The DSS was extracted using dry milling (DM-DSS) and wet milling (WM-DSS) methods. The physico-chemical properties and surface morphology of the extracted starches were examined and analysed. Besides that, the efficiency of the extracted starch to remove colour, COD, suspended solid and turbidity were also evaluated and compared. Based on the results obtained, the WM-DSS showed better starch characteristics with high purity and smooth granule particles compared to DM-DSS. In addition, WM-DSS also recorded better leachate contaminants removal even at low dosage. Nevertheless, the performance of leachate contaminants removal for both extracted starch was very low. Thus, further chemical modification is required in order to improve the coagulation ability of the extracted starch. This finding indicated the potential of WM-DSS to be use as a coagulant aid for landfill leachate treatment. (paper)