An approach for the application of the Ecological Footprint as environmental indicator in the textile sector

The Ecological Footprint (EF) is a recent concept which has widely been used as an indicator of environmental sustainability applied to individual lifestyles, regions, nations or even the world. Recently, its application to enterprises has been proposed. In the present study, a textile tailoring plant has been analysed. The overall purpose of this study was to develop a tool useful for evaluating the environmental impact evolution due to the performance of the plant, as well as for comparing the environmental behaviour of different tailoring processes. Therefore, the selected data were those from the manufacturing work. Data were divided in three main categories: energy, resources and waste. The principal contribution to the final EF (expressed in hectares of land) was the resources category, mainly due to the high value associated to the cloth. The consumed energy was the second contributor, while the waste category remained in third place. The final outcomes were divided by the production rates to obtain a comparable relative index, easy to be interpreted by the different stakeholders. This is of special importance for a Company involved in Corporate Social Responsibility and thus meant to have a general communication strategy.

Integration of equalisation tanks within control strategies for anaerobic reactors. Validation based on ADM1 simulations

The combination of equalisation tanks and anaerobic digesters represents a typical design scenario within the treatment of industrial wastewaters. In this context, if the hydraulic capacity of the equalisation tanks is effectively handled, significant improvements in the performance of anaerobic digesters can be achieved in terms of process stability and biogas production. This paper presents a rule-based control strategy for anaerobic reactors with the objective of maximising in the long-term the net production of biogas. The control algorithm combines real-time information about the state of the anaerobic digester with on-line measurements about the wastewater volume of the equalisation tank in order to set permanently the appropriate production of biogas. Such a strategy guarantees a continuous influent flow so that emptying and overflowing episodes in the equalisation tank can be prevented. Aiming at a further full-scale implementation, only reliable and cost-effective on-line instrumentation has been considered within the control architecture. The performance of the proposed control approach has been validated for an anaerobic hybrid configuration (AHR) by simulation using the IWA ADM1 model.

Characterization of anaerobic granular sludge developed in UASB reactors that treat ethanol, carbohydrates and hydrolyzed protein based wastewaters

In this work, granules developed from UASB reactors that treat different types of wastewaters (ethanol, carbohydrates and protein-based synthetic wastewaters) were studied. Granule parameters (size distribution; density; settlement characteristics; elemental composition; acidogenic and methanogenic activities) were analyzed along with micro-organisms identified by FISH to better understand granule behavior and its formation process. Micro-organisms distributions in anaerobic granules are highly dependent on the type of treated wastewater. Granules developed in a UASB reactor that treats wastewater with a high content of carbohydrates presented high acidogenic bacteria colonization. Members of Methanosaetaceae were the dominant methanogens in the studied granules, and Methanobacteriales appear to be co-dominant in the granules developed with carbohydrates and protein-based wastewaters.

Integrated pollution prevention and control for heavy ceramic industry in Galicia (NW Spain)

The heavy ceramic industry (building materials and refractory products manufacture) is an important source of pollutants to the environment. For this reason these industrial sub-sectors are included in prevention and control pollution policies, specifically those of the European Union. The IPPC Directive pays particular attention to the mineral industries, not least to the ceramic industry (epigraph 3.5, Annex I). In this paper, a methodology which is being applied to support IPPC installations and the competent administrative authority in Galicia (NW Spain) is presented. For that, the Galician heavy ceramic industry is analysed, as also are the ways to study the Best Available Techniques (BAT) with a view to establishing the emission limit values (ELV) for each specific case. Hence, a technological state of the art has been carried out for both sub-sectors, from the point of view of implementation of the IPPC in Galicia. Following this, the processes are described briefly and an analysis of the consumption and emission levels of the main pollutants is made. An inventory that includes the best environmental practices and the preventive and abatement candidate techniques as BAT was elaborated for both considered sub-sectors. An information data sheet for each candidate BAT is presented as a method to help both the industries and the competent authority to identify a candidate technique of the inventory as BAT. Three illustrative examples of the application of this procedure are presented for different emissions to environmental media for Galician installations.

Selection of variables using factorial discriminant analysis for the state identification of an anaerobic UASB-UAF hybrid pilot plant, fed with winery effluents

Anaerobic wastewater treatment has become a widely used method for wastewater depuration, and has been applied in a wide range of situations, from urban wastewater to highly toxic industrial wastewater. Particularly it has been successfully applied to the treatment of the beverage industries effluents. To avoid the destabilization of the system a monitoring diagnosis and control system of the depuration processes is necessary. The cost of this system is an important issue, that depends on the number of parameters that must be controlled for an adequate performance of a wastewater plant control system. This work shows how the classic statistical classification techniques can be applied to determine the number variables that must be monitored to achieve an adequate performance of anaerobic UASB-UAF hybrid Pilot Plant monitoring and control system. The obtained results had not been unique, so different combinations of variables can be selected for a good wastewater treatment process control. Economic or technical criteria may be considered to determine the final variables set in each particular situation.

Characterization, management and treatment of wastewater from white wine production

During a 16 months period, the characteristics of the wastewaters generated in a Rias Baixas winery (Spain) producing white wine were determined: The characterization study showed that white wine wastewater had an average CODt and TSS values of 7.3 and 5.2 kg/m3, respectively being the ratio wastewater/wine produced of about 1.6-2.0 L/L and the ratio between load pollution and produced wine of 9.7 kg(CODt)/m3(WINE). A strategy for the management of wastes and wastewaters allowed for an important reduction of a 55% of wastewater generation to be achieved. In order to select a suitable technology for the treatment of wastewaters two configurations were tested at pilot scale: i) An Anaerobic Filter (AF) of 430 L followed by an activated sludge unit of 510 L and: ii) one activated sludge unit of 510 L. The results showed that the anaerobic/aerobic configuration was more flexible as it adapted quickly to the different loads and flows produced during the different phases through the year. Besides it allowed higher COD removals (98.5-99.2%) to be achieved and proved to permit a quicker re-start up after starvation periods.

Winery effluent treatment at an anaerobic hybrid USBF pilot plant under normal and abnormal operation

A 1.1 m3 hybrid USBF fully instrumented pilot plant has been used for the treatment of diluted wine for four years. In this work, the performance of the wastewater treatment plant (WWTP) during start up and operation (normal operation and overload experiments) is shown. A complete description of the treatment process behaviour (gas and liquid phase composition and anaerobic sludge characteristics) is given by on-line and off-line monitoring of 28 process variables. The results presented here demonstrate the reliability of this technology for the treatment of wastewater from seasonal processes, such as winery wastewaters, during a long period of time (four years). Furthermore, the USBF reactor presented very short start up periods after short and long shut down of the WWTP and rapidly turned back to normal operation after suffering a complete destabilization due to organic overload. Both effluent and biogas were of good quality. Dissolved organic carbon concentration in the effluent was always lower than 100 mg DOC l(-1) under normal operation, while methane concentration in the biogas was in the range 70-74%, making it suitable for energy recovering.

Surgical salvage of pelvic recurrences from colorectal tumors

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Background: The morbidity of pelvic recurrences from colorectal tumors (PRCT) represents a challenge for the oncology multidisciplinary team. Surgical treatment is the best option for palliation and in several series it offers long term local control in 30% of the cases. Objective: To perform a retrospective analysis of patients (pts) surgically resected for PRCT in terms of: time to progression after surgical salvage (TP) and specific suvival (SS). Correlatives studies were performed with clinic and pathologic factors, surgical procedures (SP), and postoperative complications in terms of TP and SS. Methods: 64 pts treated (June 1994 - February 2005) were identified (women: 30), median age 63 years, site of the primary: rectum 48, sigmoid 16; Median number of resected nodes: 8 (r: 2 - 20) in pts with negative nodes and 15 (r: 6 - 42) in pts with positive nodes; primary treatment: surgery (S): 22 pts, S + chemotherapy (CT): 18, S + radiotherapy (RT): 4, S + CT/RT: 17, CT + S: 2 pts, QT/RT + CX: 1; in 7/64 a Miles procedure was performed as primary therapy, median disease free interval: 15 months; site of initial recurrence: locoregional 58 (90%), locoregional + systemic 10%. Pain and bleeding were the most frecuent symptoms. Results: The strategy in PRCT was: S: 29 pts, S + RT: 15, S + CT/RT: 9, CT/RT + S: 7, S + CT: 2, CT + S: 1, RT + S:1; IORT: 18/64; external beam RT: 17/64, 6 pts required Miles; type of resection: R0: 50/64 (78%), R1: 8/64 (12%), R2: 3/64 (5%) and 3 (5%) unknown. Median duration of surgery: 4 hours, abscesses and fistulas were the complications most frequently observed. Median time to progression (TP): 12 months, site of recurrence (56/64 pts) post salvage surgery: pelvic: 22 pts, extrapelvic: 6 pts, combined: 10 and unknown 18. Eleven pts are free of disease. In 16 pts more than one surgical salvage was perfomed. The specific survival was 21 months (IC 95% 37 - 61 m). Conclusions: In this serie surgical salvage of PRCT showed one year of local control disease, even in pts with R2 and with moderate morbidity. The surgical decision must be individualized and in the context of a trained surgical team.

No significant financial relationships to disclose.

Poorly differentiated neuroendocrine carcinoma-small cell of the gastrointestinal tract. Institutional experience

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Background: PDNEC-Small cell (OMS Clasification, grade III)of the GI tract are rare diseases. Small cel represent 0,1% to 1% of all GI malignancies, and are included in the group of PDNEC but: Do these group behave biologically and respond to treatment in the same way? Trying to elucidate this matter, we performed a retrospective analysis of our group of pts. with PDNEC. Methods: A database search was done. from 1997 to 2005 we found 31 pts. with PDNEC/Small cell from the GI Tract treated in our Centers. A review of the clinical records was performed with special interest in response rate and overall survival. interest. Results: 14 pts. were informed by the pathologist at diagnosis PDNEC and 17 pts. as small cell. Median age: 50 years (r 19–84). The most common primary site was Esophagus-Stomach (29%), followed by pancreas 9 pts. (29%. 9 pts.(29%) presented with metastatic disease with unknown orimary Sistemic symptoms were common. A majority of our pts. (61%) presented with overt metastases. The liver was involved in 14 pts. (61%) follow by lymph nodes in 5 (16%). The most common chemotherapy used was a combination Platinum based. Overall response rate was 43%. TTP for all pts were 7 months (95% IC 0.34–0.69). Overall survival was 12 months (95% IC 0,31–0,70). We observed differences in term of overall survival and TTP in favor of PDNEC (15 months vs 10 months and 8 vs 4 months respectively) pNS. Conclusions: PDNEC-Small cell had bad prognosis. In our Serie we found differences between both groups, although not statiscally significant (due to a low number of patients). Definitive data of treatment for the management of this group of pts. still lacks.

No significant financial relationships to disclose.

Granulation in high-load denitrifying upflow sludge bed (USB) pulsed reactors

In this work, the effect of the application of a pulse system to anoxic upflow sludge bed (USB) denitrifying reactors for enhancing sludge granulation was studied. In all, three 0.8 L reactors (two operated with flow pulsation, P1 with effluent recycling and P2 without recycling, and one without pulsation and effluent recycling, no pulsation (NP)) were fed with a mixture of NaNO3 and glucose and inoculated with methanogenic granular sludge. The organic loading rate (OLR) and the nitrogen loading rate (NLR) were progressively increased and, at the end of the experiment, extremely high values were obtained (67.5 kgCOD/m3d and 11.25 kgN-NO3-/m3 d). Ammonia and nitrite accumulation in reactor NP were important in the maturation stage, decreasing the denitrification efficiency to 90%, while in reactor P1 only low nitrite values were obtained in the last few days of the experiment. In reactor P2, nitrogen removal was 100% most of the time. Several operational problems (flotation and the subsequent wash out of biomass) appeared in the NP reactor when working at high denitrifying loading rates, while in reactors P1 and P2 there were no notable problems, mainly due to the good characteristics of the sludge developed and the efficient degasification produced by the pulsing flow. The sludge formed in the NP reactor presented a flocculent structure and a total disintegration of the initial methanogenic granules occurred, while a small-sized granular biomass with a high specific density was developed in the pulsed reactors due to the shear stress produced.

A hydrogen-based variable-gain controller for anaerobic digestion processes

An easy-to-implement controller based on gas phase measurements for anaerobic digestion processes was developed. The controller is based on the indirect control of COD in the effluent by means of controlling the hydrogen concentration in the biogas. The fast response of hydrogen under destabilizations, such as those caused by overloads, guarantees an early actuation on the system before it destabilizes. The controller is designed such that it brings the anaerobic digestion process to maximum capacity by pushing it to maximum methane production as long as hydrogen remains low. Experiments have been conducted to test the controller under organic over- and underload situations and promising performance was achieved. Further experiments must be carried out to validate the controller under a wider spectrum of situations to enable its robust industrial application.

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.

Anaerobic and aerobic continuous cultures of Saccharomyces cerevisiae : comparison of plasmid stability and EXG1 gene expression

Two bioreactor continuous cultures, at anaerobic and aerobic conditions, were carried out using a recombinant Saccharomyces cerevisiae strain that over-expresses the homologous gene EXG1. This recombinant system was used to study the effect of dissolved oxygen concentration on plasmid stability and gene over-expression. Bioreactor cultures were operated at two dilution rates (0.14 and 0.03 h(-1)) to investigate the effect of other process parameters on EXG1 expression. Both cultures suffered severe plasmid instability during the first 16 generations. Segregational plasmid loss rate for the aerobic culture was two-fold that of the anaerobic operation. In spite of this fact, exo-beta-glucanase activity at aerobic conditions was 12-fold that of the anaerobic culture. This maximal activity (30 U ml(-1)) was attained at the lowest dilution rate when biomass reached its greatest value and glucose concentration was zero.

Improvement of the properties of granular sludge in UASB reactors by flow pulsation

The objective of this work is to improve the characteristics of granular sludge by modification of the hydraulics of the bed through flow pulsation. Three UASB reactors, two operated with pulsing flow (P1 and P2) and a third without pulsation (NP), were started-up. Both recycling and feeding flow were pulsed in the reactor P1, while in reactor P2, only the feeding was pulsed. A high increase in the removal capacity and stability were achieved by applying pulsation in reactors P1 and P2 when compared to the non-pulsed one. Besides, pulsation promotes the formation of particles of smaller size and higher porosity, thus increasing the specific surface of the bed and consequently, the specific activity. In fact, while reactors P1 and P2 had a 95% COD removal when working at high organic loading rates (12 kg COD/m3 x d), reactor NP only reached 6 kg COD/m3 x d with 85% of removal capacity.

An expert system for monitoring and diagnosis of anaerobic wastewater treatment plants

In this paper, an expert system (ES) developed for the monitoring and diagnosis of anaerobic wastewater treatment plants (AWT), is presented. The system was evaluated in a hybrid pilot plant of 1.1 m3 located in an industrial environment for the treatment of wastewaters from a fibreboard production factory. The reactor is a hybrid USBF, combining an upflow anaerobic sludge blanket (UASB) in the lower part and an upflow anaerobic filter (UAF) at the top.

Influence of pulsation on start-up of UASB reactors

The aim of this work is to study the influence of pulsation on the start-up of lab-scale UASB reactors. Pulsation was produced by an Elastic Membrane Pulsator (EMP). The application of this device in previous works improved the performance of continuous fixed-bed fermentors and reduced the formation of preferential pathways, the retention of gas metabolites within the bed and the resistance to mass transfer. These characteristics seem to be suitable for feeding UASB reactors. In this work, the influence of pulsation frequency was studied in two pulsed UASB reactors operated in parallel with a non-pulsed one. One of them (P1) operated at high frequencies (periods of 50 and 200 s between each pulsation) and the other (P2) at low frequencies (periods of 3600 and 900 s between each pulsation). An important improvement of the removal efficiency for pulsed reactors with respect to the non-pulsed one was obtained. The structure of the biomass was observed at the end of the process by scanning electron microscopy. In general, granulation of biomass was improved when operating in pulsing form.

Expert system for the on-line diagnosis of anaerobic wastewater treatment plants

A diagnosis system for anaerobic wastewater treatment processes is presented. The system is able to recognise the state and trend of the operation and suggest the appropriate control action. The on-line variables measured were gas flow rate and composition (methane and carbon monoxide), feed and recycling flow rates, temperature and pH, while the manipulable inputs are feed, recycling and buffer-addition flow rates. The diagnosis system comprises a structured rule base, incorporating expert knowledge using fuzzy logic features. The structure of the system is based on the classification of information related to the process in three categories: i) the state of the process, ii) its trend and iii) the recommended set-point values for the inputs manipulated: feeding, buffer and recycling pumps. The system was applied to diagnose the operation of a 1.1 m3 hybrid UASB-UAF treating wastewater from a fibreboard production factory under different conditions (overload and underload), corresponding to some of the typical causes of destabilisation in anaerobic wastewater treatment plants. These situations require control action in order to maintain the stability and the treatment capacity of the reactor. The application of the system developed for the purpose of managing the situation proved to be reliable for supplying the actual state and trend of the process, as well as the adequate set point values to recover stable operation and/or to avoid further destabilisation.

Population dynamics of a continuous fermentation of recombinant Saccharomyces cerevisiae using flow cytometry

The plasmid instability of genetically modified microorganisms during prolonged bioreactor operations is one of the major problems to be overcome in the production of recombinant proteins. The use of flow cytometry to monitor a fermentation process with recombinant cells in a CSTR is reported here. This technique has been applied to determine the fraction of plasmid-bearing cells (P+) of a recombinant Saccharomyces cerevisiae strain harboring the EXG1 gene in a continuous stirred tank bioreactor with a working volume of 2 L. The different levels in the expression of the EXG1 gene, which encodes the enzyme exo-beta-glucanase, were used to determine the P+ fraction. Other parameters such as viability, cellular protein, cell size and structure were also monitored using flow cytometry. This technique has two main advantages over the conventional method of determining the P+ fraction (plating in selective and non-selective solid media): (a) it takes a very short period of time to obtain a measurement that provides multiple parametric information; and (b) it is more representative of the bioreactor cell population since it can analyze thousands of cells in the same sample. A continuous operation (432 h) with the recombinant strain in a CSTR was carried out to test the application of this technique. Measurements of cellular exo-beta-glucanase activity and cellular protein content closely correlates to the measured fraction of plasmid-containing cells in the population. Moreover, the standard deviation of the fraction of P+ cells determined using this technique was very low (about 2%). Recombinant protein production also increased the size of the yeast cells, whereas the recombinant cells also had a more complex internal structure than the non-recombinant host strain.