[Numerical simulation and operation optimization of biological filter].

BioWin software and two sensitivity analysis methods were used to simulate the Denitrification Biological Filter (DNBF) + Biological Aerated Filter (BAF) process in Yuandang Wastewater Treatment Plant. Based on the BioWin model of DNBF + BAF process, the operation data of September 2013 were used for sensitivity analysis and model calibration, and the operation data of October 2013 were used for model validation. The results indicated that the calibrated model could accurately simulate practical DNBF + BAF processes, and the most sensitive parameters were the parameters related to biofilm, OHOs and aeration. After the validation and calibration of model, it was used for process optimization with simulating operation results under different conditions. The results showed that, the best operation condition for discharge standard B was: reflux ratio = 50%, ceasing methanol addition, influent C/N = 4.43; while the best operation condition for discharge standard A was: reflux ratio = 50%, influent COD = 155 mg x L(-1) after methanol addition, influent C/N = 5.10.

[Detecting organophosphorus pesticide in water environment using an enzyme biosensor].

Based on a screen printed carbon electrode which contained a sensitive film prepared by crosslinking acetylcholine esterase (AChE) with glutaraldehyde on the surface of working electrode, an amperometric enzyme biosensor was taken on the determination of organophosphorus (OP) pesticide in water environment. Cyclic voltammetry was applied to assess the coherence of prepared screen printed electrodes. The results show that the variation is less than 10%. The sensor sensitivity was optimized with respect to content of enzyme, crosslinker and substrate. The best sensitivity is obtained using 0.2% of glutaraldehyde, 0.5 mg/mL of AChE and 10 mmol/L of acetylthiocholine chloride (ATChCl). Amperometric I-t curve was conducted to detect the decrease rate of the current after the addition of two kind of OPs (terbufos and parathion), respectively. The detection limit for two kind of OPs are found to be 1 ng/mL with the linear range 1 ng/mL - 10 000 ng/mL. Cyclic voltammetry was conducted to detect parathion on the sensors which immobilized AChE by physical adsorption. The results show that it can achieve a better sensitivity than amperometric I-t curve.