Degradation of wine industry wastewaters by photocatalytic advanced oxidation.

Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.     

Effects of solid retention time on the performance of submerged anoxic/oxic membrane bioreactor.

In this study, four similar bench-scale submerged Anoxic/Oxic Membrane Bioreactors (MBR) were used simultaneously to investigate the effects of solids retention time (SRT) on organic and nitrogen removal in MBR for treating domestic wastewater. COD removal efficiencies in all reactors were consistently above 94% under steady state conditions. Complete conversion of NH(4+)-N to NO(3-)-N was readily achieved over a feed NH(4+)-N concentration range of 30 to 50 mg/L. It was also observed that SRT did not significantly affect the nitrification in the MBR systems investigated. The average denitrification efficiencies for the 3, 5, 10 and 20 days SRT operations were 43.9, 32.6, 47.5 and 66.5%, respectively. In general, the average effluent nitrogen concentrations, which were mainly nitrate, were about 22.2, 27.6, 21.7 and 13.9 mg/L for the 3, 5, 10 and 20 days SRT systems, respectively. The rate of membrane fouling at 3 days SRT operation was more rapid than that observed at 5 days SRT. No fouling was noted in the 10 days and 20 days SRT systems during the entire period of study.     

Microbial conversion of selected azo dyes and their breakdown products.

Four selected azo dyes (acid orange 6, acid orange 7, methyl orange and methyl red) were completely decolourised in the presence of anaerobic granular sludge, while only methyl red was degraded in aerobic conditions using a conventional activated sludge. Additional experiments with culture broth devoid of cells showed that anaerobic decolourisation of azo dyes was performed by extracellular reducing agents produced by anaerobic bacteria. This was further confirmed by abiotic experiments with sulphide and NADH. The presence of redox mediators such as riboflavin led to dramatic acceleration of the anaerobic biodecolourisation process. The azo dye reduction products were found to be sulphanilic acid and 4-aminoresorcinol for acid orange 6; sulphanilic acid and 1-amino-2-naphthol for acid orange 7; N,N-dimethyl-1,4-phenylenediamine and sulphanilic acid for methyl orange; and N,N-dimethyl-1,4-phenylenediamine and anthranilic acid for methyl red. Anaerobic toxicity assays showed that the azo dyes were more toxic than their breakdown products (aromatic amines), except 1-amino-2-naphthol. In the presence of activated sludge, only anthranilic acid was completely mineralised while sulphanilic acid was persistent. 4-aminoresorcinol, 1-amino-2-naphthol and N,N-dimethyl-1,4-phenylenediamine underwent autooxidation in aerobic conditions yielding coloured polymeric products. On the contrary, in the presence of granular methanogenic sludge, 4-aminoresorcinol, 1-amino-2-naphthol and anthranilic acid were quantitatively methanised, sulphanilic acid was partially (70%) mineralised while N,N-dimethyl-1,4-phenylenediamine was only demethylated producing 1,4-phenylenediamine as an end product.     

Rapid and comprehensive indicator for evaluation of performance of treatment processes and of river waters.

Naturally occurring UV active compounds, commonly present in almost all source waters, can be rapidly monitored by their ultraviolet absorbance at 260 nm (E260). Herein, the extent of correlation between the E260 and the removal efficiency of the hazardous contaminants, endocrine disrupters and dioxins, were investigated using various treatment and river source waters. The detection of various types of hazardous contaminants using sophisticated analytical methods, such as high resolution gas chromatography (HRGC)/high resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC)/inductively coupled plasma (ICP)/mass spectrometry (MS), as well as various short-term bioassays, can require hours or even days for results to be obtained. The removal of the E260 correlated well with those of individual contaminants, such as endocrine disruptor chemicals and dioxins, with the various treatment processes employed. In the plots of the endocrine disrupters against the DOC/E260, a correlation was found with the endocrine activity of the Korean/Japanese river waters employed in this study.     

Estimation and comparison of nitrogen loads and attenuation in agricultural catchments of Japan and Korea.

To help in clarifying the relationship between the time lag and attenuation of nitrogen (N) loads generated in agricultural catchments, long-term trends in activities that generate N loads and in environmental N loads were estimated in catchments in Japan and Korea dominated by non-point-source emissions. Our approach used statistical data and geographical information system software to analyze pollutant loads. The method was successful in both countries because of the availability of well-developed statistics, geographical information, and weather and water quality monitoring systems, and the accumulation of research data concerning the generation of N loads and the fate of N in soils. Comparison of environmental loads with the loads observed in river water at the outlet of each catchment revealed that: (1) the effect of changes in the environmental load in a catchment appeared almost immediately in the river water quality in Korea, but did not appear clearly even 10 years later in Japan; and (2) the strength of the attenuation appeared to be much lower in Korea than in Japan. These findings suggest that regional characteristics play important roles in the sensitivity of water quality to load-generating activities.     

Colloidal silica removal in coagulation processes for wastewater reuse in a high-tech industrial park.

Four experiments of coagulation and flocculation were conducted to investigate the characteristics of colloidal silica removal in a high-tech industrial wastewater treatment plant for reclamation and reuse of the effluent. Experimental results illustrated that poly-aluminium chloride (PACl) showed higher performances on colloidal silica removal than alum. Interestingly, the two coagulants demonstrated the same capacity on silica removal. The specific silica removal capacity was approximately 0.135 mg SiO2/mg Al2O3 when the dosage of coagulants was in the range 30-150 mg/L Al2O3. In addition, the silica was reduced significantly at the condition of pH above 8. Experimental data implied that precipitation of aluminium flocs was the major mechanism for colloid silica removal in PACl and alum coagulation, besides, charge adsorption was also important for improving removal efficiency. Moreover, the addition of polyacrylic acid (PAA) as a flocculant could slightly advance silica removal in the PACl coagulation. The combined PACl/PAA/flocs coagulation was effective for the removal of colloidal silica, soluble COD, and turbidity and also suitable as a pretreatment unit in wastewater reclamation and reuse processes.     

Multicriteria procedure for the design and the management of infiltration systems.

Infiltration systems are frequently used as an option to manage urban storm drainage. By reducing flows and volumes in downstream sewers or in surface waters, they decrease the overflows and make it possible to recharge groundwater. They come in various forms with different uses; therefore, their performance is diverse and integrates multiple aspects. Consequently, a multicriteria approach was developed in order to quantify the performance of these systems and to help in decision making problems. For that purpose, a list of performance indicators integrating technical, economical, environmental and social aspects was developed. The performances were defined with the help of a working group composed of engineers from different technical or strategic departments from Greater Lyon and researchers from different fields. The paper presents the last version of the performance indicators tested according to a set of quality requirements: availability of data, relevance, fidelity, precision, sensitivity/robustness. This critical review of the set of indicators has led us to redefine a certain number of indicators, identify numerous biases and allow putting forward general instructions for criterion or indicator construction. The last phase is to propose multicriteria decision aid methods; a procedure using ELECTRE methods should be used.     

Bank Monitoring and Environmental Risk

Abstract:  Loan announcement effects for 152 Canadian companies are examined to investigate the efficiency of monitoring by banks facing lender environmental liability. Market reaction to the announcement of bank debt to 'environmental' firms is more positive and significant than for 'non-environmental' firms and, for firms in industries with a higher likelihood of experiencing spill events, is more positive and significant, reinforcing earlier results that establish a relationship between specific loan/borrower characteristics and announcement period excess returns and providing further evidence on the 'uniqueness' of bank loans by demonstrating the superior ability of banks to monitor corporate borrowers exposed to environmental liability.     

Effects of soil erosion on water quality and water uses in the upper Phong watershed.

The main objective of this paper is to simulate the effects of soil erosion on river water quality and on agricultural production as a result of the transformation of forestlands in the catchment of the upstream Phong River. Suspended solids carry down attached nutrients and agricultural chemicals causing water pollution in the downstream. There are four different types of land use in this simulation, namely forestlands, flatland and highland sugarcane plantation areas, and paddy fields. The highest mean annual amount of soil erosion is from paddy fields (585,700 tons/year), followed by highland (73,800 tons/year) and flatland (63,950 tons/year) sugarcane plantation areas and forestlands (41,800 tons/year), respectively. However, as most of paddy fields are located in a low land and are wet type cultivations, the soil erosion occurred has less impact on river water quality and its production compared to the soil erosion from the steeper slopes of highland plantation areas. Under the resource-based agriculture, the sugarcane production is mainly increased by expanding the plantation areas leading to a significant loss of topsoil and a considerable reduction of agricultural production. Soil erosion contributes to an increase in the average annual suspended solids concentration by 72 mg/l.