Occurrence and removal of six pharmaceuticals and personal care products in a wastewater treatment plant employing anaerobic/anoxic/aerobic and UV processes in Shanghai, China.

The occurrence and removal of six pharmaceuticals and personal care products (PPCPs) including caffeine (CF), N, N-diethyl-meta-toluamide (DEET), carbamazepine, metoprolol, trimethoprim (TMP), and sulpiride in a municipal wastewater treatment plant (WWTP) in Shanghai, China were studied in January 2013; besides, grab samples of the influent were also taken every 6 h, to investigate the daily fluctuation of the wastewater influent. The results showed the concentrations of the investigated PPCPs ranged from 17 to 11,400 ng/L in the WWTP. A low variability of the PPCP concentrations in the wastewater influent throughout the day was observed, with the relative standard deviations less than 25 % for most samples. However, for TMP and CF, the slight daily fluctuation still reflected their consumption patterns. All the target compounds except CF and DEET, exhibited poor removal efficiencies (<40 %) by biological treatment process, probably due to the low temperature in the bioreactor, which was unfavorable for activated sludge. While for the two biodegradable PPCPs, CF, and DEET, the anaerobic and oxic tank made contributions to their removal while the anoxic tank had a negative effect to their elimination. The tertiary UV treatment removed the investigated PPCPs by 5-38 %, representing a crucial polishing step to compensate for the poor removal by the biologic treatment process in winter.

[Effects of soil compositions on sorption and desorption behavior of tetrachloroethylene in soil].

Sorption and desorption play an important role in the transport and the fate of tetrachloroethylene (PCE) in soil. In order to examine influences of different soil compositions on PCE sorption-desorption, equilibrium batch experiments were carried out using four sorbents (natural soil with 2.23% total organic carbon (TOC), H2O2-treated soil, 375 degrees C-treated soil and 600 degrees C-treated soil) with different initial PCE liquid concentrations (c0). The effects of main parameters (TOC, soft carbon, hard carbon, minerals, c0) on PCE sorption-desorption were investigated. At 16 degrees C, when c0 was increased from 5 to 80 mg x L(-1), the results showed that sorption and desorption isotherms of PCE on four sorbents can be best described by the Freundlich model (r2 > 0.96). The sorption contribution rate of SOM was higher than 60% in natural soil, and hard carbon was the main influencing factor,while the desorption contribution rate of SOM was close to that of minerals in natural soil, and soft carbon accounted for more than 80% in the total desorption contribution rate of SOM. In addition, the higher the c0, the higher the sorption contribution rate of PCE in hard carbon and desorption contribution rate of PCE in soft carbon and minerals were. Moreover, desorption of PCE from four sorbents exhibited hysteresis, and hard carbon played a remarkable role in the hysteresis of natural soil.

[Characteristics and influencing factors of trichloroethylene adsorption in different soil types].

Adsorption plays an important role in the transport and the fate of trichloroethylene (TCE) in soil. Six types of soil, including two types of natural soil with different organic carbon content and four types of soil with the low aggregation of "soft carbon" pre-treated by hydrogen peroxide or with all organic carbon removed by high temperature ignition from the original soil, were adopted as adsorbents. The effects of parameters (organic carbon content and composition, minerals, the initial TCE concentration, solution pH, moisture content and ionic strength) on TCE adsorption capacity were examined. The results showed that the soil adsorption isotherm was non-linear within the experimental range. The TCE adsorption capacity was increased and the contribution rate of the minerals to the sorption was reduced with the increase of the organic carbon content. The adsorption of TCE in the soil was the result of the combined action of both organic carbon and minerals, in which organic carbon played a major part, whereas the role of minerals could not be neglected. As the initial TCE concentration increased, the contribution rate of the minerals to the sorption went down. The adsorption isotherm of "soft carbon" was linear, while the "hard carbon" was non-linear. Moreover, the adsorption capacity was increased by increasing the ionic strength. In contrast, neither pH nor moisture content had any influence on TCE adsorption.

An activated sludge model based on activated sludge model number 3 for full-scale wastewater treatment plant simulation.

A modified model based on the activated sludge model no. 3 was established to simulate a full-scale municipal wastewater treatment plant in Shanghai, China. The activated sludge model no. 3 was modified to describe the simultaneous storage and growth processes occurring in activated sludge systems under aerobic and anoxic conditions. The mechanism of soluble microbial product formation and degradation by microorganisms was considered in this proposed model. Three months simulation was conducted including soluble chemical oxygen demand, NH4(+)-N, NO(X)(-)-N and T-N parameters, and compared with measured data from the Quyang wastewater treatment plant. Results indicated that the calculated effluent chemical oxygen demand and NH4(+)-N using this proposed model were in good agreement with the measured data. Results also showed that besides inert soluble organic matter contributing to the effluent chemical oxygen demand, soluble microbial products played an important part in the effluent chemical oxygen demand and, therefore, demonstrated that these products composed an important portion of effluent soluble chemical oxygen demand in wastewater treatment plants and should not be neglected.