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Epidemiology
Published in Samuel C. Morris, Cancer Risk Assessment, 2020
Polycyclic organic matter (POM) has probably received greater attention in terms of quantitative dose-response function development than any “chemical.” POM includes the polycyclic hydrocarbons and other heterocyclic organic compounds which often contain oxygen, nitrogen, or sulfur as well as hydrogen and carbon. Such an organic mix of pollutants results from the combustion of fossil fuels, although the total pollution mix from combustion also contains inorganic compounds such as sulfur dioxide which may also enter into the dose-response relationship. It is a good example of the problems of developing and using dose-response curves for chronic exposure to a complex mixture or a class of chemical pollutants using an exposure index. Essentially all of the commonly used POM dose-response functions are based on one of three studies. Some of these were introduced earlier in this chapter.
Influence of Design and Operation Parameters in the Organic Load and Nutrient Removal in Constructed Wetlands
Published in María del Carmen Durán-Domínguez-de-Bazúa, Amado Enrique Navarro-Frómeta, Josep M. Bayona, Artificial or Constructed Wetlands, 2018
“Organic matter” in the context of wastewater treatment wetlands refers to a complex set of organic compounds. Particulate organic matter, or POM, is defined as material which is large enough to be retained on 0.45 mm filter (Kadlec and Wallace 2009), and may include:Biomass of living or dead microbes;Extracellular polymeric substances (EPS), also known as biofilm, and sludge;Above and belowground biomass of macrophytes, and litter.
Parameters affecting enhanced coagulation: a review
Published in Environmental Technology Reviews, 2018
Kanika Saxena, Urmila Brighu, Aditya Choudhary
NOM can be defined as a heterogeneous mixture of organic materials which is found in all natural waters [3,7]. The suspended portion of the NOM is known as particulate organic matter (POM) and the dissolved portion as dissolved organic matter (DOM). NOM is ubiquitous in natural waters and represents one of the major pollutants in low alkalinity and low turbidity source [8]. NOM varies spatially as well as temporally in terms of acidity, molecular weight, molecular structure and charge density [9–12]. NOM molecules are complex mixtures of aromatic and aliphatic molecules with organic acid groups, the majority of which are negatively charged at neutral pH [13]. The quality and quantity of NOM depend on the source of water and on the biogeochemical cycle of the nearby environment. NOM may have distinctive characteristics associated with its source (e.g. vegetation, soil, wastewater). The origin of NOM can be allochthonous (terrestrially derived) or autochthonous (in-situ or algal) [14]. DOM from aquatic algae has a relatively large nitrogen content and low aromatic carbon and phenolic contents. On the other hand, terrestrially derived DOM has relatively low nitrogen content but large amounts of aromatic carbon and phenolic compounds [15]. NOM may also vary in the same location seasonally, due to rainfall, snowmelt runoff, floods or droughts [3]. It is this heterogeneity of NOM which makes its removal challenging.
Ozonation of polyoxymethylene effluent in a rotating packed bed
Published in Environmental Technology, 2019
Dan Wang, Wei Wang, Taoran Liu, Mingjun Shan, Guangjun Li, Moses Arowo, Lei Shao
Polyoxymethylene (POM) is widely used in automotive, consumer goods, machinery industry as well as other plastic industries [1]. Its demand, particularly in china, is increasingly growing owing to rapid development of emerging industries. POM effluent, which is generated in the production of POM and contains many toxic and recalcitrant pollutants such as formaldehyde, s-Trioxane and dioxolane, is highly toxic and thus poses a serious threat to the environment. Due to the disinfectant properties of formaldehyde, it is difficult to treat the POM effluent directly by the conventional biological methods. It is thus necessary to pre-treat POM effluent by other means to degrade the organic pollutants into small molecule compounds so as to enhance the biodegradability of the POM effluent.