The control of biodegradable substances is the key issue in evaluating the short and long-term emission potential and environmental impact of a landfill. Aerobic and anaerobic indices, such as respirometric index (RI) and biomethane potential production (GB21), can be used in the estimation of the stability of solid waste samples. Previous studies showed different degrees of relationship between BOD₅/COD ratio compared with RI4. Aim of this study is to standardize the parameter BOD₅/COD ratio and to test the methodology under different operating conditions (dynamic or static leaching and leaching duration, 6 and 24-h) keeping constant temperature and liquid/solid ratio (L/S=10 l/kg(TS)), with the introduction of a COD fractioning method. The COD fractioning is based on the differentiation between the soluble fraction (COD(sol)) and the colloidal fraction (COD(coll)) using a flocculation method. The BOD₅/COD and the BOD₅/COD(sol) indices are both consistent and significant and can be used as stability indices. The BOD₅/COD ratio does not seem to be influenced, for the same test duration, by the type of test, static or dynamic. In the same way the longer test duration (24-h) does not influence significantly the values of BOD₅/COD ratio. As a consequence a leaching test duration of 6-h is preferable to avoid the beginning of the hydrolysis and oxidation processes.
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http://dx.doi.org/10.1016/j.wasman.2012.04.001 | DOI Listing |
Microorganisms
December 2024
Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, MD 20742, USA.
Accurate detection of viable O157:H7 in fresh produce wash water is critical for ensuring food safety and mitigating foodborne illnesses. This study evaluated an optimized on-filter propidium monoazide (PMA)-quantitative PCR (qPCR) method for detecting viable O157:H7 in romaine lettuce wash water, involving PMA pretreatment on a filter to block DNA amplification from dead cells. The method consistently detected viable cells across chemical oxygen demand (COD) levels of 1000 and 200 mg O/L, with no significant differences ( > 0.
View Article and Find Full Text PDFToxics
December 2024
Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541006, China.
This study analyzed three years of data (2021-2024) from three wastewater treatment plants (WWTPs), namely D, X, and T, in the main urban area of Handan, a typical city in the southern Hebei region, and investigated the influent characteristics and impact of temperature on these wastewater treatment facilities. With 90% assurance, the overall influent conditions of the three WWTPs in this region were normal. However, Plant T operated more effectively with slightly lower BOD/COD (B/C), organic carbon/total phosphorus (C/TP), and organic carbon/total nitrogen (C/TN) ratios in the influent.
View Article and Find Full Text PDFWater Res
January 2025
Department of Civil and Environmental Engineering, University of Florence, Via di S. Marta, 3, 50139, Firenze, Italy.
The performance of Upflow Anaerobic Sludge Blanket (UASB) bioreactors treating sulfate (SO) -rich effluents depends on multiple factors, including microbial interactions and operational conditions. The high complexity of these systems necessitates the use of mathematical modelling tools to better understand the process and predict the long-term impacts of various operational variables. In this work, a mathematical model describing the long-term operation of a sulfate-fed 2.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, 610041, PR China; Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture and Rural Affairs, Chengdu, 610041, PR China. Electronic address:
To solve the problem of low chemical oxygen demand (COD)/N and poor efficiency of single-stage sequencing batch reactor (SBR) or anoxic/oxic process (A/O) in treatment of digested effluent of swine wastewater, combined SBR-A/O and A/O-SBR processes were employed in the addition ratios of 0, 10%, 30%, and 40% (V/V)) of raw swine wastewater (RS). Analysis of pollutants removal performance of SBR-A/O and A/O-SBR systems showed no significant difference between the two systems without RS addition. However, after adding RS, the pollutants removal efficiency of the two systems increased with the increase in the ratio of RS, with SBR-A/O system presenting better pollutants removal performance than A/O-SBR system.
View Article and Find Full Text PDFBioresour Technol
January 2025
Department of Frontier Science for Advanced Environment, Graduate School of Environmental Sciences, Tohoku University, 6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan; Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan. Electronic address:
This study investigated the performance and phase-specific characteristics of mesophilic co-digestion of food waste (FW) with rice straw (RS) at different RS proportions (40 %, 60 %, and 80 %), as well as mono-digestion of RS. The system achieved optimal performance at 40 % RS content, with a methane yield of 383.8 mL/g-VS and cellulose removal efficiency exceeding 75 %.
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