Background, Aim, And Scope: Chemical oxygen demand (COD) is used as a discharge standard parameter in wastewater treatment plant design, environmental modelling and many other applications. Chloride interference is an important problem of COD measurement for wastewaters containing low organic matter and high chloride concentrations. In case of chloride concentrations up to 2,000 mg/L, mercury sulphate addition at a ratio of 10:1 (HgSO(4):Cl(-)) can adequately mask the interference. When chloride concentration exceeds 2,000 mg/L, this ratio becomes ineffective to hinder the interference. At this point, it is proposed to use a greater and constant ratio of mercury sulphate addition. However, this application sometimes results in extra mercury sulphate addition which is not necessary. Even in some cases, greater addition of mercury sulphate alone is not a solution to erroneous measurement results. The purpose of the study is to determine optimum HgSO(4):Cl(-) ratios according to the chloride concentrations of the samples and to show the importance of the strength of the digestion solution for the correct determination of the COD parameter.
Materials And Methods: CODs of the synthetic samples containing varying COD and chloride concentrations were measured by closed reflux colorimetric method using three digestion solutions having different strengths.
Results: It is indicated in this study that a constant ratio of mercury sulphate can only prevent chloride interference up to a specific chloride concentration.
Conclusions: Achieving high precision results in case of low organic matter and high chloride concentration can only be possible by both decreasing the concentration of oxidant and adding mercury sulphate.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1007/s11356-010-0341-z | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Anaerobic fermentation of straw with sulfate addition: A suitable approach for straw utilization in mercury-contaminated areas.
J Environ Manage
December 2024
Key Laboratory of Karst Georesources and Environment (Guizhou University), Ministry of Education, Guiyang, 550025, China.
Returning raw straw to the soil can significantly elevate soil methylmercury (MeHg) and crop mercury (Hg) levels, underscoring the need to investigate safer approaches to straw utilization in mercury-contaminated regions. In this study, rice straw underwent anaerobic fermentation with the addition of sulfate, and the resulting fermentation products were utilized in a pot experiment involving water spinach to assess the impact of anaerobically fermented straw return on soil Hg methylation and its bioaccumulation. Findings revealed that the addition of sulfate during straw fermentation markedly increased the fermentation degree of the products, and sulfate was converted into organic sulfur-containing ligands that can functionalize the fermentation residuals.
View Article and Find Full Text PDFRole of Methanosarcina in mercuric mercury transportation and methylation in sulfate-driven anaerobic oxidation of methane with municipal wastewater sludge.
Environ Res
December 2024
College of Resources and Environment, Southwest University, Chongqing, 400715, China.
Sulfate-driven anaerobic oxidation of methane (AOM) and anaerobic digestion (AD) with municipal wastewater sludge containing heavy metals may provide favorable conditions for the biogeochemical transformation of mercury (Hg) by methanogens and methanotrophs. However, it remains largely unclear what Hg-methylators functioned and what role Methanosarcina played in these processes. Here, we performed sulfate-driven AOM following AD with Hg-containing wastewater sludge and investigated the role of microbes, especially Methanosarcina, in the biogeochemical transformation of Hg based on 16S rRNA amplicon and metatranscriptomic sequencing.
View Article and Find Full Text PDFMethylmercury degradation by hot spring sulfur-linked microbial communities as a dominant pathway in regulating mercury speciation.
Water Res
January 2025
Universite de Pau et des Pays de l'Adour, E2S UPPA, CNRS, Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux (IPREM), Pau 64000, France. Electronic address:
Sulfidic hot springs harbor unique microbial communities and are important in mercury (Hg) species transformations, although the fine scale drivers of these processes remain poorly understood. Here we studied Hg speciation in water, biofilms, and sediment across three sampling seasons in a French sulfidic hot spring with low Hg concentrations. Microbial Hg species methylation and demethylation potentials were evaluated using incubation experiments with species-specific Hg isotope tracers.
View Article and Find Full Text PDFArticle Synopsis
- The study focuses on a type of salt extracted from vegetable stems in Ethiopia, analyzing its mineral content, health benefits, and taste.
- Techniques like Optical Emission Spectroscopy and Flame Atomic Absorption Spectroscopy were used to ensure the salt was safe and rich in beneficial minerals like potassium while being low in sodium.
- Results showed that rats consuming this salt had significantly lowered blood pressure compared to those fed regular salt, suggesting it could be a healthier alternative for people with hypertension.
System efficiency of methylmercury production, an important indicator for evaluating the long-term risk of mercury: From a case study in the Jiaozhou Bay to global coastal seas.
J Hazard Mater
December 2024
Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China. Electronic address:
With the implementation of the Minamata Convention, total Hg (THg) in coastal seas are expected to be reduced. However, methylmercury (MeHg) levels in aquatic environments depend not only on THg, but also the system efficiency of MeHg production (represented by MeHg/THg ratio in seawater) whose variations with time remain unclear. By choosing the Jiaozhou Bay (JZB) as a typical coastal system, combined with the published data from the global coastal systems, system efficiency of MeHg production in coastal seas were investigated.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!