A new design of flocculation tank: the Turbomix applied to weighted flocculation.

As far as flocculation is concerned, the agglomeration of suspended particles into flocs is highly linked to the hydraulic behaviour of the agitation. The Turbomix is a special design of mixing tank; its design was developed to better control the flow during the flocculation stage. It enables a significant decrease in footprint of the process. The combination of the Turbomix and ballasted flocculation has been studied during pilot trials in terms of treatment efficiency. Its controlled hydraulic behaviour explains the efficiency of the process as proved by CFD investigation.     

Oxidation and mineralisation of substituted phenols by Fenton's reagent and catalytic wet oxidation.

Catalytic abatement of solutions of 1,000 mg/L in phenol, ortho and para nitrophenol and ortho and para cresols was acomplished by using two catalytic systems. Fenton's reagent was used at 50 degrees C by adding 10 mg/L of ferrous cation and different dosages of H2O2. The mixture was reacting isothermically in a batch way during 3 hours. Catalytic wet oxidation (CWO) was carried out by using a commercial Activated Carbon, Industrial React FE01606A, CWO runs were carried out in a fixed bed reactor (FBR) with concurrent upflow. Temperature and oxygen pressure of the reactor were set to 160 degrees C and 16 bar, respectively. While phenols are quicky oxidised by the Fenton reagent higher mineralisation was obtained in the CWO process.     

Evaluation of constructed wetlands by wastewater purification ability and greenhouse gas emissions.

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.     

Possibility of sewage and combined sewer overflow reuse with biological aerated filters.

The secondary effluent from municipal plants in Korea generally represents higher BOD with lower SS. Therefore, more soluble forms of organics and NH4-N need to be removed to improve its effluent for reuse. In this study reuse possibility of secondary effluent and CSO (combined sewer overflow) using BAF (biological aerated filter) was evaluated. The tertiary application with 1.2 h EBCT, SS, BOD and COD showed stable concentrations less than 1.3, 1.3 and 6.2 mg/L, respectively. Nitrogen could be nitrified even at 7 degrees suggesting BAF can be used for a water reuse method as well as an effective add-on facility in cold regions. However, BAF was not stable with CSO application at increased flow rates suggesting CSO must be equalised prior to application. Disinfection was necessary even during normal weather conditions.     

Estrogenic personal care products in a greywater reuse system.

The occurrence and fate of parabens in a greywater system was assessed. The potential for removal of residual paraben concentrations in effluent greywater with chlorine dioxide was also investigated. The influent to the greywater plant was characterised by considerable variation, with concentrations from below the detection limit to 40 microg/L and the five commonly used parabens in consumer products were frequently detected. After the biological treatment only two paraben were detected with concentration from 65-120 ng/L. Chlorine dioxide treatment of the biologically treated effluent with dosages down to 0.75 mg/L resulted in more than 97% reduction of all parabens. Formation of the by-product chloroform was insignificant from the chlorine dioxide treatment.     

The impact of time duration between trades on the price of treasury note futures contracts

Recent research in finance has indicated that the institutional structure in which financial asset prices are determined can have a nontrivial impact on pricing. This report examines transaction level data for Treasury Note futures contracts traded at the Chicago Board of Trade (CBOT) to identify institutional, or market microstructure, impacts on the pricing of these contracts. Relatively few articles have conducted empirical research on the microstructure of U.S. futures trading due to the limited availability of comprehensive transaction level data from the futures exchanges. This report uses the CBOT's Computerized Trade Reconstruction database, a comprehensive transaction level dataset, to identify the price impact of the time duration between trades in a manner analogous to that of A. Dufour and R. F. Engle (2000). Unique differences from prior research include the application to futures contracts with their relative higher frequency of trading, as well as the investigation of the price impact of the number of active traders present on the trading floor and the trading volume. Subsequent price and sign of trade significantly relate to the time duration between trades, the number of floor brokers, and the trading volume. © 2004 Wiley Periodicals, Inc. Jrl. Fut Mark 24:965–980, 2004     

Contract modifications and the basis behavior of live cattle futures

The purpose of this study was to assess the basis behavior of the Live Cattle Futures contract at the Chicago Mercantile Exchange (CME) before and after the 1995 contract changes. Additionally, an alternative method of basis calculation utilizing weighted mean futures prices versus settlement futures prices was compared to determine which method provides a better representation of the basis level. Within a regression model with heteroskedascity error framework, we found that the level of nearby basis in the period after June 1995 has shifted lower and the average monthly open interest of net commercial long positions has substantially increased after the contract modifications. These empirical results are consistent with the notion that more long activity entered the market in response to the contract modifications. Additionally, an alternative (new) measure of basis calculation (cash price minus weighted mean futures price) produced similar results to two other commonly used measures. In conclusion, the 1995 contract changes have neither increased nor decreased the volatility of live cattle basis. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:557–590, 2004     

Developing Countries as Plaintiffs and Defendants in GATT/WTO Trade Disputes

Developing countries have been increasing their participation in the formal institutions and proceedings of the multilateral trading system. A prominent example is their more frequent involvement as defendants and plaintiffs in GATT/WTO trade disputes. This paper provides an initial economic appraisal of developing country performance in the GATT/WTO dispute settlement system. We measure the economic resolution of these disputes through trade liberalisation gains, and our results suggest that developing country plaintiffs have had more success under WTO disputes than was the case under the GATT. We also document evidence on potential determinants of this success: the capacity for plaintiffs to make credible retaliatory threats and the guilty determinations by GATT/WTO panels. Finally, there is also some evidence that developing countries have recognised the importance of retaliatory threats and have responded by changing their pattern of dispute initiation under the WTO to better take advantage of the instances in which they have sufficient leverage to threaten retaliation and induce compliance with GATT/WTO obligations.