Expansion of Dreissena into offshore waters of Lake Michigan and potential impacts on fish populations

Lake Michigan was invaded by zebra mussels (Dreissena polymorpha) in the late 1980s and then followed by quagga mussels (D. bugensis) around 1997. Through 2000, both species (herein Dreissena) were largely restricted to depths less than 50 m. Herein, we provide results of an annual lake-wide bottom trawl survey in Lake Michigan that reveal the relative biomass and depth distribution of Dreissena between 1999 and 2007 (although biomass estimates from a bottom trawl are biased low). Lake-wide mean biomass density (g/m²) and mean depth of collection revealed no trend between 1999 and 2003 (mean = 0.7 g/m² and 37 m, respectively). Between 2004 and 2007, however, mean lake-wide biomass density increased from 0.8 g/m² to 7.0 g/m², because of increased density at depths between 30 and 110 m, and mean depth of collection increased from 42 to 77 m. This pattern was confirmed by a generalized additive model. Coincident with the Dreissena expansion that occurred beginning in 2004, fish biomass density (generally planktivores) declined 71% between 2003 and 2007. Current understanding of fish population dynamics, however, indicates that Dreissena expansion is not the primary explanation for the decline of fish, and we provide a species-specific account for more likely underlying factors. Nonetheless, future sampling and research may reveal a better understanding of the potential negative interactions between Dreissena and fish in Lake Michigan and elsewhere.     

气浮—水解酸化—IC—曝气—混合反应—砂滤工艺处理造纸制浆废水

采用气浮—水解酸化—IC—曝气—混合反应—砂滤组合工艺处理造纸、制浆生产废水,运行结果表明,当造纸废水水量12 000 m3/d、CODCr≤1 670 mg/L、BOD5≤750 mg/L、SS≤1 200mg/L,制浆废水水量6 000 m3/d、CODCr≤14 500 mg/L、BOD5≤5 100 mg/L、SS≤3 430 mg/L时,处理出水CODCr≤90 mg/L、BOD5≤30 mg/L、SS≤30 mg/L,可满足《制浆造纸工业水污染物排放标准》(GB 3544—2008)要求。     

A new side stream process for easily degradable industrial waste waters to avoid sludge bulking.

A new treatment scheme for the treatment of easily biodegradable industrial waste waters has been developed. The side stream treatment of dairy waste water with the excess sludge from the domestic treatment line of the regional treatment plant Bad V?slau has been operated successfully for a period of three years during which the industrial load stemming from the dairy increased from 800 kg COD/d to 2,500 kg COD/d with peak loads up to 5,000 kg/d. Despite of the increased load to the treatment plant the total aeration tank volume had not been increased. This treatment is performed in an existing aeration tank of the WWTP (V = 1,800 m3) which is now used as contact tank for the combined aeration of dairy waste water and excess sludge from the domestic treatment line (volume aeration tank = 15,000 m3). In this tank the easily degradable substrate from the industrial waste is mainly adsorbed to the biological sludge and after a mechanical dewatering transferred to the anaerobic digester where it yields in an increased gas production. The filtrate of the dewatering process is completely free from biodegradable material and can without danger of bulking be fed to the aeration tank of the domestic treatment line. The new process has proven to be extremely flexible since already now daily peak loads exceeding the design load by more then 60% could be treated in the plant without any problems. Compared to other alternatives for the dairy waste water treatment that were investigated during this study, the new side stream process is very advantageous. No other pre-treatment process for industrial waste water could have been operated under comparable loading conditions without severe operating problems.     

Fate and transport of oil in sediment laden marine waters

Spilled oil when present in sediment-enriched waters, is known to interact with sediments. Oil droplets form aggregates with sediments due to collision and dissolved oil partitions (absorption and adsorption) into sediments due to capillarity and surfactant ions. This may change the fate and transport of both oil and sediments. Interaction with sediments acts as a natural oil removal process. This has been recognized as a crucial component in developing oil spill countermeasures. However, no comprehensive models are currently available to describe the process. This paper presents a novel numerical model developed to simulate oil-sediment interaction and transport in near-shore waters. The present model simulates, oil and sediment transport, oil-sediment aggregate (OSA) formation, oil partitioning into sediments, and sediment aggregation. The critical information provided by the model such as the fraction of oil removed due to sediment interaction would be useful in developing oil spill countermeasures.The model results are compared with the limited data from laboratory experiments and show a good agreement. Scenario simulations showed that up to 65% of released oil may be removed from the water column as OSAs. They further showed that when oil droplets and sediment particles are smaller (less than 0.1 mm), the amount of OSAs formed is higher. According to the scenario simulations, the amount of oil partitioned into sediments is 4–5 orders of magnitude smaller than the amount of OSAs formed.     

Treatment of non-biodegradable cutting oil wastewater by ultrasonication-Fenton oxidation process.

To treat cutting oil wastewater produced in metal surface treatment industry, Ultrasonication (US)-Fenton process, which is one of the advanced oxidation processes, was used. The optimum conditions to treat non-biodegradable pollutants using the US-Fenton process were that the application rates of H2O2 and FeSO4 were 10% and 3 g/L, respectively, the value of pH was 3, and the ultrasonication time was 30 min. It identified non-degradable pollutants such as ethylene diamine tetraacetic acid (EDTA) and Triethanolamine (TEA) in the cutting oil wastewater. TLC analysis of two compounds of treated water by the coagulation process was similar to that of raw water. However, TLC analysis of two compounds of US-Fenton process was different from that of raw water, meaning that US-Fenton process decomposed the EDTA and TEA. To study the possibility of application with the US-Fenton process to pilot plant, the pollutants treatment efficiency of three different methods, such as US-Fenton process, activated sludge process and coagulation process, in continuous experiments were compared. The removal rate of pollutants by the US-Fenton process according to the effluent time was higher than any other processes. The removal rates of COD, SS, T-N and T-P by US-Fenton process were 98, 93, 75 and 95%, respectively.     

稠油废水混凝法除硅工艺研究

稠油废水温度高、碱性大、溶解性硅含量相对较高。针对硅的不同存在形态,探讨了稠油废水混凝除硅的机理和效果。试验结果表明,混凝工艺可去除稠油废水中活性硅和非活性硅,MgCl2的投加和pH的升高可有效改善PAC对活性硅和非活性硅的去除效果。通过单因素正交试验可优化确定PAC、MgCl2、助凝剂的投加量及pH分别为330mg/L、150mg/L、2mg/L和11～12。     

反应吸附—气浮—深层过滤工艺处理油田含聚废水

采用反应吸附—多相气浮—有机粘土深层过滤组合工艺处理新疆准东采油厂的含聚废水,实现了废水中浮油、分散油、乳化油与水相的有效分离,同时浊度也明显降低。结果表明,当LPA、LPB、PAM投加量分别为150 mg/L、12 mg/L和60 mg/L,有机粘土投加量5 g/L,处理后废水CODCr、石油类、SS可分别由680 mg/L、98.6 mg/L、56.2 mg/L降至98 mg/L、5.4 mg/L、4.5 mg/L。     

初始组构影响砂土液化势的细观数值模拟

基于PFC2D椭圆颗粒单元的二次开发,通过制备3种不同初始颗粒定向的数值试样,分别为随机定向（R试样）、水平定向（H试样）和竖直定向（V试样）,研究了初始组构对砂土液化势的影响。数值试验采用常体积（面积）循环等应变幅加荷条件,试验过程在对比分析3种不同颗粒定向试样液化宏观力学响应的同时,从颗粒尺度层面探讨了不同颗粒定向试样的初始组构特征,揭示了初始组构影响砂土液化势的细观力学机理。结果表明,颗粒规则定向的试样其抗液化强度要高于随机定向试样,在细观机理上与不同颗粒定向试样的初始平均接触数有关,砂土的液化过程是一个组构各向异性的演化过程。     

Detecting changes in fish behaviour in real time to alert managers to thresholds of potential concern

Fish behaviour is one biological organisational level regularly used to assess the state of freshwater ecosystems and can be monitored using fish telemetry methods. The development of activity sensors incorporated into fish telemetered tags allows for non-spatial movement to be detected and is increasingly used to understand the energy budgets and response and fine-scale behaviour of fishes. In addition, detecting tagged fish remotely and in real time highlights the need to process fish activity data in near real time to make it relevant to managers in the water resource sector. Our study on Labeobarbus natalensis, a cyprinid, in the uMngeni River in KwaZulu-Natal, South Africa, adapted and then tested the exponentially weighted moving average (EWMA), as developed for financial predictive modelling, using activity data from fish. To determine changes in behaviour, we compared the EWMA-predicted fish behaviour against the present fish behaviour. We showed that the EWMA could adequately detect changes in behaviour on both individual and population levels. Changes in behaviour are potentially indicative of a change in environmental conditions and thus were developed into management alerts. We conducted further analyses using generalised additive mixed models (GAMM) to determine the relationship between fish activity and the environmental data collected. The GAMMs helped determine the potential drivers for changes in behaviour where the EWMA could detect these in real time. Detecting changes in behaviour in real time as a result of environmental variables can identify thresholds of potential concern influencing management decisions and allow managers to respond, contributing to improving effective freshwater management.     

规整聚结除油工艺的应用

大庆油田采油一厂三元复合驱石油废水处理站,处理规模4000m3／d,以规整聚结除油工艺为主体,聚结填料选用聚氯乙烯,其空间结构独特,传质条件好,是聚结机理丰富的新型规整填料。经过3年的运行表明,此工艺不需投加任何药剂,运行费用低,抗冲击负荷能力强,聚结除油效果稳定,各项出水指标满足三元复合驱回注水质标准。     

初始组构影响砂土液化势的细观数值模拟研究

本文基于PFC2D椭圆颗粒单元的二次开发,通过制备三种不同初始颗粒定向的数值试样,分别为随机定向（R试样）、水平定向（H试样）和竖直定向（V试样）,研究了初始组构对砂土液化势的影响。数值试验采用常体积（面积）循环等应变幅加荷条件,试验过程在对比分析三种不同颗粒定向试样液化宏观力学响应的同时,从颗粒尺度层面探讨了不同颗粒定向试样的初始组构特征,揭示了初始组构影响砂土液化势的细观力学机理。结果表明,颗粒规则定向的试样其抗液化强度要高于随机定向试样,在细观机理上不仅与不同颗粒定向试样的初始平均接触数有关,而且与孔隙形态和孔隙率的分布密切相关;砂土的液化过程是一个组构各向异性的演化过程。     

Application of MesoHABSIM and target fish community approaches to restoration of the Quinebaug River,Connecticut and Massachusetts,USA

The study of the Quinebaug River in Massachusetts and Connecticut, USA was the first application of the Target Fish Community (TFC) and Mesohabitat simulation (MesoHABSIM) approaches to determine a river's biophysical conditions, habitat deficits and potential improvement measures. These approaches were created in concert with assessment of hydromorphology, fish and invertebrate fauna composition, as well as hydrology and water temperature. This paper presents how both approaches created a framework for comprehensive and quantitative analysis of human‐induced alterations and helped to identify a list of effective restoration measures. Copyright © 2008 John Wiley & Sons, Ltd.     

Investigation of multimodal zeta potential and size distribution in chemical pulp process water.

Multimodal zeta potential distribution in chemical birch pulp process water was studied by filtrating the water into fractions and subsequently measuring zeta potential, charge quantity, turbidity and organic substances. Filtrations were made using 12 microm, 1.6 microm, 1.2 microm, 0.45 microm and 0.1 microm membranes. The number of populations with different zeta potentials diminished with filtration. With the unfiltrated water, 12 microm and 1.6 microm filtrates, three or four different zeta potentials were observed. When the filtration was performed with a 1.2 microm membrane or smaller, only two populations of different zeta potentials were detected. The charge quantity steadily approached zero from unfiltrated water towards a 1.6 microm fraction filtrate. After that, it remained constant. Turbidity constantly decreased when using smaller membranes. The amount of wood extractives decreased to half with 0.1 microm filtration. No significant difference in the amount of carbohydrates and lignin between the filtrated fractions and the unfiltrated water was detected. A comparison dealing with particle size analysis between two different apparatuses was also made.     

Zeta potential measurement on the surface of blue-green algae particles for micro-bubble process.

Any kind of blue-green alga produces metabolites of musty substances and toxins. Therefore, it is necessary to remove the blue-green algae, and processing also including nutrient removal is desired for the water quality improvement of eutrophic lakes. The purpose of this study has been to investigate the possibility of a flotation system using a hybrid technique (chemical compounds and electrostatic bridge) applied to raw water containing phytoplankton with high pH of water, and to examine the zeta potential value of phytoplankton surface and the removal efficiency for phytoplankton, ammonia, nitrogen, and phosphoric acid.The results were as follows: firstly, zeta potential of M. aeruginosa particles was observed to achieve charge neutralization on their surface by adhesion of magnesium hydroxide precipitation with increasing pH. Secondly, maximum removal efficiency concerning chlorophyll-a was observed as 84%, and this efficiency was obtained in the condition of pH > 10, and magnesium hydroxide precipitation was observed. Thirdly, in the pH condition that the maximum removal efficiency of chlorophyll-a was obtained, the removal efficiency and the amount of decrease of NH(4)-N and PO(4)-P before and after the change of pH values were observed as 6.7% (0.04 mg-P/L) and 63.6% (0.07 mg-N/L), respectively.     

Natural origins of off-flavours in fish related to feeding habits.

The objective of our study was to survey the accumulated 2-methylisoborneol (MIB) and geosmin (GSM) in fillets of five important farmed fish species in Hungarian aquaculture in relation to MIB and GSM concentrations in water and sediment in the aquatic systems where they were raised: (the planktivorous silver carp (Hypophthalmichthys molitrix), the herbivorous grass carp (Ctenopharyngodon idella), the bottom-feeding omnivorous common carp (Cyprinus carpio), the omnivorous tilapia (Oreochromis niloticus) and the carnivorous African catfish (Clarias gariepinus)). Water, sediment and fish samples were collected from different experimental aquatic systems which included a combined aquaculture-algae (CAA) system, effluent-fed fishponds, a pond recycling system and a traditional fishpond. MIB and GSM contents were extracted with distillation-headspace solid-phase-microextraction (SPME) and extracts analysed by GC-MS. Results showed that off-flavour contents in fish fillets were related to the feeding habits of the studied fish species. Higher GSM concentrations were found in the fillet of bottom-feeding common carp than in the silver carp or African catfish in all studied aquatic systems. Usually, low GSM concentrations were detected in the water of fishponds but sometimes the levels of this odour compound in carp fillet were well above the limits of human detection. This suggests that the off-flavour tainting of common carp may originate from the sediment or benthic algallactinomycete sources. Negligible MIB levels were found in all samples in all of the studied aquatic systems.     

破舱油船水下油品泄漏过程的舱压效应研究

该文采用VOF模型和标准k-?湍流模型来实现负压条件下破舱油船水下油品泄漏,并用缩尺模型试验进行验证。通过对油品泄漏入海量及泄漏速度等泄漏特征参数的分析,获得舱压在泄漏动力中的作用及舱压在油品泄漏过程不同阶段的作用机理。研究表明:舱压在油品泄漏动力中的作用主要表现在受阻泄漏阶段,而自由泄漏阶段中油品重力的动力作用明显;舱压对油品的泄漏入海量影响较大,对压载舱内进水量及油品积累量影响小;在受阻泄漏阶段,舱压越小,油品泄漏入海率及压载舱内油品积累率越小,而进水率越大。     

Integrated modelling of nitrate loads to coastal waters and land rent applied to catchment-scale water management.

The EU Water Framework Directive (WFD) requires an integrated approach to river basin management in order to meet environmental and ecological objectives. This paper presents concepts and full-scale application of an integrated modelling framework. The Ringkoebing Fjord basin is characterized by intensive agricultural production and leakage of nitrate constitute a major pollution problem with respect groundwater aquifers (drinking water), fresh surface water systems (water quality of lakes) and coastal receiving waters (eutrophication). The case study presented illustrates an advanced modelling approach applied in river basin management. Point sources (e.g. sewage treatment plant discharges) and distributed diffuse sources (nitrate leakage) are included to provide a modelling tool capable of simulating pollution transport from source to recipient to analyse the effects of specific, localized basin water management plans. The paper also includes a land rent modelling approach which can be used to choose the most cost-effective measures and the location of these measures. As a forerunner to the use of basin-scale models in WFD basin water management plans this project demonstrates the potential and limitations of comprehensive, integrated modelling tools.     

Emerging approaches to integrated urban water management: cluster scale application.

Integrated Urban Water Management (IUWM) seeks to extend Water Sensitive Urban Design to a total water cycle approach that includes reuse of wastewaters. This paper investigates the appropriateness of environmental technologies for application at a cluster scale in IUWM. Many environmental technologies are economically or physically unsuited to use on a municipal or unit scale. Cluster scale is a middle ground that will allow such environmental technologies to achieve full potential. The concept of cluster scale and the application of environmental technologies at this scale are discussed along with some examples of suitable technologies.     

Winery solid residue revalorization into oil and antioxidant with nutraceutical properties by an enzyme assisted process.

Revalorization of the winery industry residue, grape seed is studied for the production of an oil and defatted meal with nutraceutical properties. Conventional grape seed oil extraction process is carried out by pressing at high temperature affecting the product quality. Oil extraction by cold pressing improves product quality, but it gives a low oil yield. Oil extracted is increased at the pressing stage, when an enzymatic pre-treatment is incorporated in to the conventional process. The yield is determined by determining the residual oil in the pressed cake. Using an enzymatic treatment during 9 hours at 45 degrees C and 50% of moisture, with a mixture of two commercial enzymes grape seed oil extraction yield by cold pressing is raised up to 72%, being a 59.4% increment in comparison to the yield obtained by the control, without enzymes. The defatted meal by enzimatic assisted process improves its phenolic compounds between 2 and 4 times, depending on the conditions of phenolics extraction in comparison to the control samples.