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Recently, there has been growing concern over the prevalence of Nonylphenol ethoxylates (NPnEOs) in the natural environment as these compounds are known endocrine disruptors. This study focuses on the seasonal variation and spatial distribution of NPnEOs in the wastewater of a full scale sewage treatment plant, operating a Biological Aerated Filter (BAF), in Harbin, a city in Northeast China. Water samples were collected seasonally from 2009 to 2010, with the findings revealing remarkable seasonal variations in the concentrations of NPnEOs. The total influent concentrations of short-chain NPnEOs (NP, NP1EO and NP2EO) measured during winter was 16 mg L−1, with decreasing concentrations observed during autumn, summer and spring of 89, 67 and 41 mg L−1, respectively. The concentrations of the short-chain NPnEOs measured during autumn become higher (89 mg L−1), with summer becoming the lowest (16 mg L−1). Although the removal efficiencies of short-chain NPnEOs in STP showed various trends in different seasons, they all achieve relatively good performance during summer and winter. The BAF process plays the main role in the elimination of short-chain NPnEOs compounds; however, the ambient temperatures were not found to significantly influence the removal efficiency of short-chain NPnEOs compounds from the STP. [ABSTRACT FROM PUBLISHER]

An SBR reactor was used to study the effect of temperature on N2O production in the process of nitrogen removal by micro-expansion aerobic granular sludge, as well as the removal efficiency of COD and ammonia nitrogen. The experiments were conducted at 21 ± 0.5°C, 26 ± 0.5°C, and 31 ± 0.5°C with low dissolved oxygen. The results showed that simultaneous nitrification and denitrification occurred in this system. The temperature had a significant influence on N2O production and N2O release rate; both increased with temperature going up. The ratios of N2O production to the influent nitrogen loading rate at 31 ± 0.5°C, 26 ± 0.5°C, and 21 ± 0.5°C were 8.07, 5.37, and 3.93%, respectively, which are higher than aerobic granular sludge. N2O release was 0.96 mg/m3at 31 ± 0.5°C, which was 1.43 and 1.37 times the production at 21 ± 0.5°C and 26 ± 0.5°C, respectively, and dissolved N2O production was 1.46 ± 0.05 mg/m3at 31 ± 0.5°C, which was 2.86 and 1.60 times the production at 21 ± 0.5°C and 26 ± 0.5°C, respectively. As a result, 26°C is recommended as a suitable temperature for reducing N2O emission and maintaining nitrogen removal efficiency in wastewater treatment. [ABSTRACT FROM AUTHOR]