Pilot-scale study of biomass reduction in wastewater treatment.

Pilot-scale experiments were continuously carried out for more than 9 months to study the excess biomass reduction effect using a biophase-separation bioreactor, which was designed based on food-chain theory. By separating the biophase in the wastewater treatment system, bacteria, protozoa, and metazoa could be separated from each other and dominated in different microbial communities. After degrading organic matter, bacteria were consumed by protozoa or metazoa in the following process in such a reactor. Thus, both chemical oxygen demand (COD) and biomass were reduced. During the process of treating restaurant wastewater, the excess biomass yield in this biophase-separation technique varied from 0.13 to 0.22 kg/kg COD removed, 50% lower than that from the reference system. Apart from low biomass production, this biophase-separation technique can simultaneously achieve a high COD removal efficiency and improve settleability of biosolids at a hydraulic retention time of 6 to 13 hours.     

Advanced treatment of wet-spun acrylic fiber manufacturing wastewater using three-dimensional electrochemical oxidation

A three-dimensional electrochemical oxidation(3D-EC) reactor with introduction of activated carbon(AC) as particle micro-electrodes was applied for the advanced treatment of secondary wastewater effluent of a wet-spun acrylic fiber manufacturing plant. Under the optimized conditions(current density of 500 A/m~2, circulation rate of 5 mL/min, AC dosage of 50 g, and chloride concentration of 1.0 g/L), the average removal efficiencies of chemical oxygen demand(COD_(cr)), NH3–N, total organic carbon(TOC), and ultraviolet absorption at 254 nm(UV_(254)) of the 3D-EC reactor were 64.5%, 60.8%, 46.4%, and 64.8%, respectively; while the corresponding effluent concentrations of COD_(cr), NH_3–N, TOC, and UV_(254) were 76.6, 20.1, and42.5 mg/L, and 0.08 Abs/cm, respectively. The effluent concentration of COD_(cr) was less than 100 mg/L, which showed that the treated wastewater satisfied the demand of the integrated wastewater discharge standard(GB 8978-1996). The 3D-EC process remarkably improved the treatment efficiencies with synergistic effects for COD_(cr), NH_3–N, TOC, and UV_(254) during the stable stage of 44.5%, 38.8%, 27.2%, and 10.9%, respectively, as compared with the sum of the efficiencies of a two-dimensional electrochemical oxidation(2D-EC) reactor and an AC adsorption process, which was ascribed to the numerous micro-electrodes of AC in the 3D-EC reactor. Gas chromatography mass spectrometry(GC–MS) analysis revealed that electrochemical treatment did not generate more toxic organics, and it was proved that the increase in acute biotoxicity was caused primarily by the production of free chlorine.     

Wastewater-nitrogen removal using polylactic acid/starch as carbon source: Optimization of operating parameters using response surface methodology

The use of PLA/starch blends for nitrogen removal was achieved. The influence of different operating parameters on responses was verified using RSM. The conditions for desired responses were successfully optimized simultaneously. Blends material may have a promising application prospect in the future. Nitrogen removal from ammonium-containing wastewater was conducted using polylactic acid (PLA)/starch blends as carbon source and carrier for functional bacteria. The exclusive and interactive influences of operating parameters (i.e., temperature, pH, stirring rate, and PLA-to-starch ratio (PLA proportion)) on nitrification (Y₁), denitrification (Y₂), and COD release rates (Y₃) were investigated through response surface methodology. Experimental results indicated that nitrogen removal could be successfully achieved in the PLA/starch blends through simultaneous nitrification and denitrification. The carbon release rate of the blends was controllable. The sensitivity of Y₁, Y₂, and Y₃ to different operating parameters also differed. The sequence for each response was as follows: for Y₁, pH>stirring rate>PLA proportion>temperature; for Y₂, pH>PLA proportion>temperature>stirring rate; and for Y₃, stirring rate>pH>PLA proportion>temperature. In this study, the following optimum conditions were observed: temperature, 32.0°C; pH 7.7; stirring rate, 200.0 r·min^-1; and PLA proportion, 0.4. Under these conditions, Y₁, Y₂, and Y₃ were 134.0 μg-N·g-blend^-1·h^-1, 160.9 μg-N·g-blend^-1·h^-1, and 7.6 × 10³ μg-O·g-blend^-1·h^-1, respectively. These results suggested that the PLA/starch blends may be an ideal packing material for nitrogen removal.     

二英类污染物生物分析方法研究进展

二英类物质具有致癌、致畸等毒理及健康效应.我国二英类物质污染源较多,分布较为广泛,因此二英监测任务十分紧迫.但是我国二英实验室相对较少,单纯的仪器分析方法不能满足监测需求,因此急需发展经济、简便、快速的生物检测方法.生物检测方法主要包含免疫类检测方法和基于芳香烃受体(AhR)信号通路的检测方法,本文着重对这两类生物检测方法的原理和进展等进行综述.     

重金属污染下龟壳攀鲈组织中ACP和AKP的活力比较

龟壳攀鲈是一种在极端污染水域中具备生存优势的鱼类,收集重污染区和轻污染区的龟壳攀鲈,并通过比较其体内各组织中的酸性磷酸酶(ACP)及碱性磷酸酶(AKP)活性来揭示其耐污能力。贵屿作为重污染区有4个采样点:大陇村、市上村、联堤村和北林村;潮州作为轻污染区有2个采样点:卧石村和洗马桥。水质结果表明,贵屿采样地水中的Pb、Cd、Cr、As、Hg含量分别是潮州采样点的27.6倍、3.9倍、5.8倍、3.9倍和3.5倍,说明贵屿采样地的污染远高于潮州的。酶活结果表明,在龟壳攀鲈所有组织中,内脏组织(胃肠、性腺、肝脏、脾脏、肾脏)中的ACP和AKP活力均高于外周组织(肌肉、鳞片、鳃);重金属污染均能提高攀鲈体内所有组织的ACP和AKP活力;AKP活性更容易受到重金属的影响,各组织的AKP活力增幅普遍超过ACP活力增幅;其中,受重金属影响最大的组织是脾脏,ACP和AKP活力可增长到2.37倍和6.21倍。这些结果说明了龟壳攀鲈可以通过显著升高内脏组织(如肠胃、肝脏、肾脏等)中ACP和AKP活性,以便更好地应对高污染环境;其中AKP更容易受到重金属的影响,适合用于作为评估污染的指标。     

Behaviour of selected endocrine-disrupting chemicals in three sewage treatment plants of Beijing, China

Occurrence and fate of eight kinds of selected endocrine-disrupting compounds (EDCs) in three sewage treatment plants (STPs) of Beijing, China was investigated. These EDCs, composed of 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (E2), estriol (E3) and 17α-ethinylestradiol (EE2), in every step of STPs, were simultaneously analysed by gas chromatography/mass spectrometry after derivatisation. All the EDCs were detected in the influents of three STPs, and BPA was the most abundant compound. The concentrations of EDCs ranged from 36.6 ng/l of 17α-E2 (STP C) to 1342.3 ng/l of BPA (STP B) in the influent sewages and from below limits of detection of E2 and E3 (STP C) to 142.5 ng/l of E1 (STP B) in the effluent sewages. The STPs could not remove alkylphenols effectively from the aqueous phase with less than 40% reduction. BPA decreased over 90%, and steroid estrogens achieved considerable reductions from 64.8% of E2 to 94.9% of E3. Generally, biological treatment was more effective in removing alkylphenols, BPA and natural estrogens from the aqueous phase than primary treatment. However, the synthetic estrogen, EE2, was mostly removed by the primary treatment with about 63.5% reduction. It is the first time that the concentration of 17α-E2 in the sewage of China was reported in this paper. The compound might have a bearing with the waste effluents of dairy farms around urban area of Beijing.     

高效填料塔生物反应器处理制药废水处理厂含硫臭气

采用装有特制ZX01型填料的生物反应器,对某药厂废水处理厂产生的含硫臭气进行了近4个月的连续脱臭试验.结果表明:该填料塔生物反应器的最大容积负荷N_v≤204g/(m³·h)时,H₂S去除率接近100%,H₂S代谢产物主要以SO₄^2-为主.采用少量含N、P等营养物的二次沉淀池出水为喷淋水,其最适喷淋率为3.56L/(L·d).该填料塔有较强的抗负荷冲击能力,塔内阻抗低,无堵塞现象,无需经常进行反冲洗,可长期稳定运行.     

青岛市废有机溶剂现状分析与评价

调查分析青岛市废有机溶剂产生现状、污染特性、处置流向及回收利用的概况。结合青岛市产业结构特点,遵循"资源化、减量化、无害化"处置原则,提出废有机溶剂管理的对策和建议。研究结果对危险废物的有效管理和促进循环经济发展具有指导意义。     

生物相分离系统的污泥减量效能

为了寻找有效的污泥减量途径,采用生物相分离系统将细菌、原生动物、后生动物及其它大型微型动物相对分离,使有机物在系统的前端被降解,而在后端则主要由原生动物和后生动物完成污泥减量化.试验结果表明,当有机负荷为4.8 kg·m-3·d-1时,生物相分离系统的污泥产率为0.1 kg·kg-1(以COD计),减量比例为80%左右.同时,系统对COD去除率超过了90%,且出水水质满足污水综合排放标准GB8978-2002的一级标准要求.