Nitrogen and phosphorus removal in an airlift intermittent circulation membrane bioreactor

A new airlift intermittent circulation integrated bioreactor was developed for simultaneous nitrogen and phosphorus removal of wastewater, in which, circulation of mixed liquid between mixing zone and aeration zone was realized by aeration power, alternately anaerobic/anoxic bio-environment in mixing zone was realized by intermittent circulation and simultaneous nitrogen and phosphorus removal was obtained through strengthened denitrifying phosphorus removal process. Removal performance of the reactor was investigated and pollutant removal and transfer mechanism in one operation circle was analyzed. The experiment results indicated that under the influent condition of chemical oxygen demand (COD) concentration of 642.1 mg/L, total nitrogen (TN) of 87.4 mg/L and PO₄^3--P of 12.1 mg/L, average removal efficiencies of COD, TN and PO₄^3--P reached 96.4%, 83.2% and 90.5%, respectively, with the hydraulic residence time of 22 hr and operation circle time of 185 min. Track studies indicated that the separation of aeration and mixing zones and intermittent circulation of mixed liquid between the two zones provided distinct biological environments spatially and temporally, which ensured the occurrence of multifunctional microbial reactions.     

利用边界层理论确定预涂动态膜生物反应器稳定曝气量的试验研究

研究了膜生物反应器中低浓度活性污泥的流变性,确定当污泥浓度低于8 000mg·L^-1时的泥水混合液近似于牛顿流体,进而利用牛顿流体力学中边界层理论计算预涂动态膜(PDM)厚度等于平板膜表面层流边界层厚度时的稳定曝气量.为保证预涂动态膜生物反应器(PDMBR)运行的稳定性,在其运行初期选择满足生物所需最佳溶解氧(DO)3～5 mg·L^-1的供氧曝气量,随后逐渐增加到稳定曝气量的运行方式.实验结果表明,此运行方式能较好地提高动态膜的稳定性,在稳定运行的31d内出水COD低于12.48 mg·L^-1,平均去除率达到97.49%,NH₄⁺-N约为5.27 mg·L^-1,平均去除率为76.13%,而操作压力仅上升至27kPa.试验后期考察了PDMBR在高于稳定曝气量下运行的稳定性,发现PDM发生脱落,从而证明利用边界层理论确定的预涂类动态膜的稳定曝气量具有一定的应用价值.     

The identification of readily bioavailable pollutants in lake shkodra/skadar using semipermeable membrane devices (SPMDs), bioassays and chemical analysis

GOAL, SCOPE AND BACKGROUND: Lake Shkodra/Skadar is the largest lake in the Balkans region and located on the border between Albania to the south and Montenegro to the north. Because of the wide range of endemic, rare or endangered plant and animal species it supports, Lake Shkodra/Skadar and its extensive associated wetlands are internationally recognised as a site of significance and importance (Ramsar site). In recent years, social and economic changes in both Albania and Montenegro have lead to unprecedented levels of urban and industrial effluent entering the lake. Of particular concern is the increasing input of toxic hydrophobic organic pollutants (HOPs) into the lake and the degree to which these compounds are available for uptake by aquatic biota. Semipermeable membrane devices (SPMDs) have been shown to sample the readily bioavailable fraction (dissolved phase) of waterborne HOPs and in doing so provide relevant data for exposure assessment. The aim of the current study was to use SPMD-based sampling in conjunction with appropriate bioassays and chemical analysis to identify readily bioavailable HOPs in the lake. METHODS: SPMDs were constructed and deployed at three sites in the Albanian sector and three sites in the Montenegrin sector of Lake Skadar/Shkodra for 21 days. Following the dialytic recovery of target analytes and size exclusion chromatographic clean-up, aliquots of SPMD samples were subjected to GC-MS scan analysis for major components, GC-MS SIM analysis for 16 priority pollutant polycyclic aromatic hydrocarbons (PP-PAHs) and assayed for EROD-inducing, estrogenic and mutagenic potential using rainbow trout liver cells (RTL-W1), the yeast estrogen screen (YES) and the Ames Test, respectively. RESULTS AND DISCUSSION: A total of 39 compounds were tentatively identified in SPMD samples from the six sampling sites. Alkylated PAHs were the most abundant and ubiquitous compounds present along with various sterols and sterol derivatives. Numerous other compounds remain unidentified. 15 of the 16 targeted PP-PAHs were present in samples from one or more of the sampling sites indicating these compounds are both readily bioavailable and widely distributed in Lake Shkodra/Skadar. Total PP-PAH concentrations ranged between 3991 ng/SPMD and 10695 ng/SPMD. Bioassays carried out on SPMD samples revealed significant EROD-inducing and estrogenic potential at five of the six sampling sites indicating toxicologically relevant compounds are readily available for uptake by resident aquatic biota. EROD-inducing potential was positively correlated with targeted PP-PAH concentration (r2 = 0.74). However, comparison of bioassay- and analytically-derived toxicity equivalents revealed targeted PP-PAHs were responsible for less than 0.06% of the total EROD-inducing potential. CONCLUSIONS AND OUTLOOK: The combination of SPMD-based sampling with appropriate bioassays and chemical analysis provided an effective tool for the identification of environmentally relevant waterborne pollutants in Lake Shkodra/Skadar. Our results show that toxicologically relevant HOPs including EROD-inducing and potentially estrogenic compounds are widely distributed in the lake and readily available for uptake by aquatic biota. Our results also suggest that alkylated PAHs rather than parent compounds may be of greater toxicological relevance in the lake. As anthropogenic influences continue to increase, SPMD-based sampling is expected to play a central role in future research concerned with the identification, monitoring and assessment of the risk posed by HOPs to Lake Shkodra/Skadar's aquatic biota.     

光导纤维生物膜碘荧光传感器的研究

把荧光素固定在经处理的生物膜上,研制成光导纤维生物膜碘荧光传感器。Ｉ－的线性响应范围为３×１０－５ｍｏｌ／Ｌ—５×１０－３ｍｏｌ／Ｌ,相对标准偏差为０６５％,响应时间为２５～３５ｍｉｎ。     

Simultaneous removal of COD and nitrogen using a novel carbon-membrane aerated biofilm reactor

A membrane aerated biofilm reactor is a promising technology for wastewater treatment. In this study, a carbon-membrane aerated biofilm reactor （CMABR） has been developed, to remove carbon organics and nitrogen simultaneously from one reactor. The results showed that CMABR has a high chemical oxygen demand （COD） and nitrogen removal efficiency, as it is operated with a hydraulic retention time （HRT） of 20 h, and it also showed a perfect performance, even if the HRT was shortened to 12 h. In this period, the removal efficiencies of COD, ammonia nitrogen （NH4^＋-N）, and total nitrogen （TN） reached 86%, 94%, and 84%, respectively. However, the removal efficiencies of NH4^＋-N and TN declined rapidly as the HRT was shortened to 8 h. This is because of the excessive growth of biomass on the nonwoven fiber and very high organic loading rate. The fluorescence in situ hybridization （FISH） analysis indicated that the ammonia oxidizing bacteria （AOB） were mainly distributed in the inner layer of the biofilm. The coexistence of AOB and eubacteria in one biofilm can enhance the simultaneous removal of COD and nitrogen.     

Integration of biological method and membrane technology in treating palm oil mill effluent

Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent (POME), posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration (UF) and reverse osmosis (RO) membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed (EGSB) reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount (except for K and Na). The high-quality effluent was crystal clear and could be used as the boiler feed water.     

用树脂—半透膜囊对水环境中有效态金属含量进行长期监测I、树脂—半透膜囊对铜的吸附及不同树脂的差别

在实验室条件下，研究了阳离子交换树脂－半透膜囊对水中游离态铜的吸附作用，比较了装填不同型号树脂的半透膜囊的吸附过程。研究结果表明，在常量阳离子含量较铜离子含量高三个数量级的条件下，所研究树脂都能选择性地吸附铜，其中Ｃｈｅｌｅｘ１００与ＡｍｂｅｒｌｉｔｅＩＲ－１２０树脂对铜的亲和性最强。吸附过程在数十天内呈线住，且远未饱和。藻类、细菌及各类杂质的存在对吸附过程有明显影响。     

用自旋标记方法研究环境诱变剂对健康人红细胞膜动态性质的影响

健康人的完整血红细胞膜用脂肪酸自旋标记物Ⅰ(12,3)和Ⅰ(1,14)标记,测得其ESR波谱·氟化钠、重铬酸钾、丝裂霉素C和秋水仙素等环境诱变剂较显著地改变膜的序参数S和旋转相关时间,尤在膜表层,S和明显增大。温度曲线表明,人血的完整红细胞膜的相变点在膜表层和深层分别是38℃和40.0℃。在诱变剂作用下,膜类酯的动力学性质有明显变化。     

用DWZ接触氧化处理工艺处理屠宰废水

实行畜禽定点屠宰后，含有大量有机污染物的畜禽屠宰废水的处理问题急需解决，经浙江省海宁市某畜禽屠宰厂运行证实，采用DWZ接触氧化处理工艺，具有投资少，占地面积小，处理效果好，抗冲击能力强，操作简便，运行费用低等特点，废水经处理后可达到GB8978－1996 Ⅰ级排放标准，得到了社会各界的广泛好评，本文主要介绍了该处理设施的处理工艺，运行特点及优越性，提供一条治理畜禽宰废水的有效途径。