The paper deals with the problem of the determination of the effects of temperature on the efficiency of the nitrification process of industrial wastewater, as well as its toxicity to the test organisms. The study on nitrification efficiency was performed using wastewater from one of Polish chemical factories. The chemical factory produces nitrogen fertilizers and various chemicals. The investigated wastewater was taken from the influent to the industrial mechanical-biological wastewater treatment plant (WWTP). The WWTP guaranteed high removal efficiency of organic compounds defined as chemical oxygen demand (COD) but periodical failure of nitrification performance was noted in last years of the WWTP operation. The research aim was to establish the cause of recurring failures of nitrification process in the above mentioned WWTP. The tested wastewater was not acutely toxic to activated sludge microorganisms. However, the wastewater was genotoxic to activated sludge microorganisms and the genotoxicity was greater in winter than in spring time. Analysis of almost 3 years’ period of the WWTP operation data and laboratory batch tests showed that activated sludge from the WWTP under study is very sensitive to temperature changes and the nitrification efficiency collapses rapidly under 16°C. Additionally, it was calculated that in order to provide the stable nitrification, in winter period the sludge age (SRT) in the WWTP should be higher than 35 days.
Photodegradation by sunlight radiation is one of the most destructive pathways for pesticides after
their application in the field. The generated photoproducts can exhibit various toxicological properties and affect non–target organisms. Sulcotrione is a herbicide believed to be a relatively non–toxic alternative to atrazine
herbicides used on corn fields. Despite many tests required for placing plant protection products on the market,
it still happens that transformation pathway and the toxicological profile of these compounds is not fully understood. The results presented in this article are complementary to the research performed by a research group
from National Center for Scientific Research (CNRS) at the University of Blaise Pascal (Auvergne, France).
Sulcotrione is one of main herbicides used to protect the maize plantations in the region of Auvergne (France),
as well as in Poland. As part of the experiments, the distribution of sulcotrione under the influence of polychromatic radiation (fluorescent lamp, l > 295 nm, suitable for environmental tests) in aqueous solution of pH 6.5
was tested. The main products of these reactions were 1H–xanthene–1,9–dione–3,4–dihydro–6–methylsulfonyl
(CP) and 2-chloro-4-methylsulfonyl-benzoic acid (CMBA), which are the result of intra-molecular cyclization
and hydrolysis of sulcotrione, respectively. These products were quantified by using HPLC-diode array detector analysis. The studies clearly show an increase in toxicity towards tested organism (Vibrio fischeri bacteria)
with the increase of irradiation time and appearance of the photoproducts. The results suggest that the observed
increase in toxicity may be rather attributed to the occurrence of the same minor photoproducts than to the
presence of the major photoproducts (CP and CMBA). Identification of the minor photoproducts could not be
performed using the current instrumental equipment.