Ozonation and catalytic ozonation - Sources of error. What do we need to know?

Due to the increasing contamination of the environment, including water pollution by numerous emerging contaminants, there is a growing interest in advanced water purification/treatment processes. A technique of particular and growing interest over the years is ozonation in its broadest sense. It is a complex process, and its course, both in the version without and with the participation of a catalyst, depends on a number of factors that can affect its efficiency and the correct interpretation of the obtained results.

Aging of drinking water transmission pipes during long-term operation as a potential source of nano- and microplastics.

Microplastics (MPs) and nanoplastics (NPs) released into drinking water from transmission pipes can pose a potential health risk to consumers. This paper presents the results of a comprehensive study of PE and PVC pipes after long-term operation in drinking water distribution networks, which confirmed that degradable polymers can be a significant source of MPs. Both plastics age relatively quickly, and the degree of damage to the pipe surface depends on the time and operating conditions.

The Role of Sulphate and Phosphate Ions in the Recovery of Benzoic Acid Self-Enhanced Ozonation in Water Containing Bromides.

The ozonation of aromatic compounds in low-pH water is ineffective. In an acidic environment, the decomposition of ozone into hydroxyl radicals is limited and insufficient for the degradation of organic pollutants. Radical processes are also strongly inhibited by halogen ions present in the reaction medium, especially at low pH.

The influence of active carbon contaminants on the ozonation mechanism interpretation.

In water treatment technology, activated carbons are used primarily as sorbents to remove organic impurities, mainly natural organic matter, but also as catalysts in the ozonation process. Commercially available activated carbons are usually contaminated with mineral substances, classified into two main groups: alkali metals (Ca, Na, K, Li, Mg) and multivalent metals (Al, Fe, Ti, Si). The presence of impurities on the carbon surface significantly affects the pH values determined for raw and ozonated carbon as well as their acidity and alkalinity.

Natural organic matter characterization by HPSEC and its contribution to trihalomethane formation in Athens water supply network.

Samples from the two main watersheds that provide Athens Water Supply and Sewerage Company (AWSSC) with raw water were examined for Dissolved Organic Carbon (DOC) and for their molecular weight distribution (MWD). In addition, water samples from water treatment plants (WTPs) and from the water supply network were examined for trihalomethane (THMs) levels. The main purpose of this study was to reveal the molecular composition of natural organic matter (NOM) and identify the individual differences between NOM from the two main Athens watersheds.

The role of wastewater treatment in reducing pollution of surface waters with zearalenone.

Zearalenone (ZEA) is a mycotoxin produced by some Fusarium species in food and feed. The toxicity of ZEA and its metabolites is related to the chemical structure of the mycotoxin, which is similar to naturally occurring oestrogens. Currently, there is increasing awareness of the presence of fungi and their toxic metabolites in the aquatic environment.

Influence of oxidation on fulvic acids composition and biodegradability.

Oxidation is well-known process of transforming natural organic matter during the treatment of drinking water. Chlorine, ozone, and chlorine dioxide are common oxidants used in water treatment technologies for this purpose. We studied the influence of different doses of these oxidants on by-products formation and changes in biodegradable dissolved organic carbon (BDOC) and molecular weight distribution (MWD) of fulvic acids (FA) with different BDOC content.

Corrosion in drinking water pipes: the importance of green rusts.

Complex crystallographic composition of the corrosion products is studied by diffraction methods and results obtained after different pre-treatment of samples are compared. The green rusts are found to be much more abundant in corrosion scales than it has been assumed so far. The characteristic and crystallographic composition of corrosion scales and deposits suspended in steady waters were analyzed by X-ray diffraction (XRD).

Reasons for the lack of chemical stability of treated water rich in magnesium.

Chemical stability of water should be high enough to ensure that the water reaching the consumers would have the same composition as at the treatment plant. The drinking water supplied by one of the water treatment plants for the city of Poznań was observed to produce periodically white non-sedimenting precipitate on boiling, deteriorating its organoleptic properties. The phenomenon was found to be related to a high content of magnesium in the water taken for treatment and low content of other ions besides bicarbonates.

Corrosion in a distribution system: Steady water and its composition.

Corrosion processes in drinking water distribution systems have been investigated for years. This paper proves the existence of a layer of steady water surrounding and partly filling corrosion scale in corroded water pipes. It is expected that steady water may substantially influence the corrosion.

Occurrence of estrogenic mycotoxin - Zearalenone in aqueous environmental samples with various NOM content.

Zearalenone is a mycotoxin produced by some Fusarium species in food and feed. Toxicity of ZEA and its metabolites is related to the chemical structure of the mycotoxins, similar to naturally occurring estrogens. Currently, there is increasing awareness of the significance of fungi and their toxic metabolites in water.

Application of fluorescence spectroscopy in the studies of natural organic matter fractions reactivity with chlorine dioxide and ozone.

The composition of natural organic matter (NOM) fractions before and after the reaction with chlorine dioxide as well as ozone was studied by means of total luminescence spectroscopy (TLS) and synchronous scanning fluorescence measurements. The excitation-emission matrices spectra (EEMs) of natural as well as oxidised NOM fractions revealed two well-resolved bands with maxima at Ex/Em of 250-265/422-452 nm and at Ex/Em 300-336/414-446 nm ascribed to humic and fulvic material. The study of emission and synchronous spectra also confirmed the presence of protein-like constituents in all examined NOM fractions.