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ab s t r ac tSimultaneous partial nitrification, anammox and denitrification (SNAD) process was developed in a sequential batch reactor (SBR), and the application of SNAD process for landfill-leachate treatment was investigated. The SNAD process was developed from the biomass of a full-scale landfill-leachate treatment plant. After the adaptation of biomass, the SBR was operated in four stages (I-IV) with varying nitrogen loading rates (NLRs), i.e. 118-280 mg-N/L/d, and organic loading rates (OLRs), i.e. 100-200 mg/L/d. The increase in the NLR has proportionately reduced the NH 4 + -N removal. However, the NO 2 --N concentration was close to zero and the NO 3 --N concentration was less than 36 mg/L in all the stages. A consistent chemical oxygen demand (COD) removal was observed in stages I to IV, which indicate that the SBR was not affected by the increase or decrease of the OLR. The total nitrogen removal in the SBR was mainly achieved by partial nitrification and anammox (69-88%) that was evaluated by a stoichiometric model. Moreover, the influence of NLR and OLR on the SNAD process was determined based on sensitivity index (SI). The SI values indicate that the SNAD process was highly affected by the influent NH 4 + -N compared to COD.

Our goal was to determine dioxin levels in 800 soil samples collected from Taiwan. An in vitro DR-CALUX® assay was carried out with the help of an automated Soxhlet system and fast cleanup column. The mean dioxin level of 800 soil samples was 36.0 pg-bioanalytical equivalents (BEQs)/g dry weight (d.w.). Soil dioxin-BEQs were higher in northern Taiwan (61.8 pg-BEQ/g d.w.) than in central, southern, and eastern Taiwan (22.2, 24.9, and 7.80 pg-BEQ/g d.w., respectively). Analysis of multiple linear regression models identified four major predictors of dioxin-BEQs including soil sampling location (β = 0.097, p < 0.001), land use (β = 0.065, p < 0.001), soil brightness (β = 0.170, p < 0.001), and soil moisture (β = 0.051, p = 0.020), with adjusted R2 = 0.947 (p < 0.001) (n = 662). An univariate logistic regression analysis with the cut-off point of 33.4 pg-BEQ/g d.w. showed significant odds ratios (ORs) for soil sampling location (OR = 2.43, p < 0.001), land use (OR = 1.47, p < 0.001), and soil brightness (OR = 2.83, p = 0.009). In conclusion, four variables, including soil sampling location, land use, soil brightness, and soil moisture, may be related to soil-dioxin contamination. Soil samples collected in northern Taiwan, and especially in Bade City, soils near industrial areas, and soils with darker color may contain higher dioxin-BEQ levels.