Humic substances mainly humic acids constitute the major fraction of natural organic matter in water supplies. They play an important role in the formation of harmful disinfection by products. Degradation of humic acids by means of ultraviolet radiation and ultrasonic irradiation processes was investigated in a laboratory-scale batch photoreactor equipped with an 300 W immersed-type medium-pres...

we proposed to use artificial channels in laboratory assays to expose periphyton to substancesreleased in rural environments in order to test the following hypotheses 1) a high concentration of humicsubstances decreases the biofilm biomass and alters its metabolism; 2) periphyton biomass and metabolism increase in response to nutrient addition in spite of the previous high nutrient concentratio...

Iron-reducing bacteria have been reported to reduce humic acids and low-molecular-weight quinones with electrons from acetate or hydrogen oxidation. Due to the rapid chemical reaction of amorphous ferric iron with the reduced reaction products, humic acids and low-molecular-weight redox mediators may play an important role in biological iron reduction. Since many anaerobic bacteria that are not...

Humic substances and other dissolved organic matter (DOM) in Lake Biwa and the surrounding rivers were investigated to elucidate their origins and behavior. An annual increase in chemical oxygen demand (COD) has been observed in the northern basin of Lake Biwa since 1985. The concentrations of dissolved organic carbon (DOC) in the northern and southern basins of Lake Biwa were 1.7-2.4 mgC/l and...

background: the use of alternative disinfectants and the control of natural organic material are two approaches that are typically applied in water treatment utilities to reduce the formation of chlorinated disinfection by-products in recent years. catalytic ozonation as a new technology is used to promote the efficiency of the single ozonation processes. the purpose of this study was to invest...

A comparison is drawn between fungal humic acid produced by Aspergillus niger X1 and soil humic acid regarding elementary and functional groups analysis. Elementary and functional groups analysis show that unhydrolyzed fungal humic acid contained more H and N per unit weight, more alcoholic OH but lower CO2H and phenolic OH groups than unhydrolyzed soil humic acids. The C and N content of 6(N) ...

Flash pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS) was used to study the structural transformations of humic fractions formed as a result of composting processes of diverse organic materials (solid wastes of wineries, solid olive-mill wastes, domestic wastes, ovine manures plus straw, and mixtures of animal manures). Sodium hydroxide-extracted total humic-like extracts (THE; humic p...

Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to bring some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mas...

Studies of the properties of soil organic matter are essential for understanding the humification reactions and soil diagenesis processes. The aim of this study is to analyse properties of peat and peat humic acids as well as factors influencing their variability. Humic acids isolated from an ombrotrophic bog peat profile were used as study objects. Relations among peat age, decomposition and h...