Construction of control charts to help in the stability and reliability of results in an accredited water quality control laboratory

Overall, laboratory water quality analysis must have stability in their results, especially in laboratories accredited by ISO 17025. Accredited parameters should be strictly reliable. Using control charts to ascertain divergences between results is thus very useful. The present work applied a methodology of analysis of results through control charts to accurately monitor the results for a wastewater treatment plant. The parameters analyzed were pH, BOD5, COD, total suspended solids, and total phosphorus. The stability of the results was analyzed from the control charts and 30 analyses performed in the last 12 months. From the results, it was possible to observe whether the results are stable, according to the rehabilitation factor that cannot exceed WN = 1.00 and the efficiency of removal of pollutants that remained above 70% for all parameters. The method of determining the technological reliability and stability of the treatment station using control charts is an efficient tool for detecting any instability in the results. These results help to monitor the results of the analyses more clearly and thus enable a rapid response to possible disturbances and maintain the quality of the analysis control, as well as determining the accreditation entities

Nitrate removal in vertical flow constructed wetland planted with Vetiveria zizanioides: Effect of hydraulic load.

tA vertical flow constructed wetland (VFCW) planted with Vetiveria zizanioides (0.24 m2× 0.70 m) intendedto receive a synthetic wastewater with high nitrate concentration was used to study the influence ofthe hydraulic load (HL) increase on nitrate load removal, keeping a low carbon nitrogen ratio (C/N).The inlet nitrate concentration was kept constant ([NO3−] = 83 ± 7 mg L−1) and four different levels of HLwere used, from 148 ± 5 to 473 ± 5 L m−2d−1; accordingly, nitrate load increased from 12.4 ± 0.7 g m−2d−1to 39.9 ± 0.7 g m−2d−1. The nitrate load removal occurred in all trials, increasing proportionally to HLand nitrate load applied, reaching a maximum value of 11.9 ± 0.7 g m−2d−1at a nitrate load appliedof 20.4 ± 1.2 g m−2d−1and HLof 239 ± 7 L m−2d−1. Beyond that maximum, a further increase in HLornitrate load applied led to a considerable decrease in nitrate load removal. Anaerobic conditions werenot detected and denitrification was observed even at 5.2 ± 1.2 mg L−1O2in influent. Toxicity signs inVetiveria zizanioides leaves were never detected and the results obtained suggest that the used plantabsorbs and assimilates nitrogen from wastewater. Although Vetiveria zizanioides is not commonly usedin constructed wetland, it proved to be very a robust, efficient and promoting system, encouraging furtherstudies

Nitrate removal in vertical flow constructed wetland planted with Vetiveria zizanioides: Effect of hydraulic load.

tA vertical flow constructed wetland (VFCW) planted with Vetiveria zizanioides (0.24 m2× 0.70 m) intendedto receive a synthetic wastewater with high nitrate concentration was used to study the influence ofthe hydraulic load (HL) increase on nitrate load removal, keeping a low carbon nitrogen ratio (C/N).The inlet nitrate concentration was kept constant ([NO3−] = 83 ± 7 mg L−1) and four different levels of HLwere used, from 148 ± 5 to 473 ± 5 L m−2d−1; accordingly, nitrate load increased from 12.4 ± 0.7 g m−2d−1to 39.9 ± 0.7 g m−2d−1. The nitrate load removal occurred in all trials, increasing proportionally to HLand nitrate load applied, reaching a maximum value of 11.9 ± 0.7 g m−2d−1at a nitrate load appliedof 20.4 ± 1.2 g m−2d−1and HLof 239 ± 7 L m−2d−1. Beyond that maximum, a further increase in HLornitrate load applied led to a considerable decrease in nitrate load removal. Anaerobic conditions werenot detected and denitrification was observed even at 5.2 ± 1.2 mg L−1O2in influent. Toxicity signs inVetiveria zizanioides leaves were never detected and the results obtained suggest that the used plantabsorbs and assimilates nitrogen from wastewater. Although Vetiveria zizanioides is not commonly usedin constructed wetland, it proved to be very a robust, efficient and promoting system, encouraging furtherstudies

Irrigation water quality in Alentejo (Portugal) study of the irrigation perimeter of the reservoir of Roxo

Alentejo is a region of Portugal located in the south of the country and the main economic activity is agriculture. In Alentejo the precipitation is very irregular. The problem of droughts often occurs. The Alqueva reservoir is the biggest reservoir in Europe and provides water for more than 120,000 hectares for agriculture. Before the use of the reservoir, the main agricultural products were cereals. Now farmers grow vegetables and they make an intensive culture of olive trees and almond trees. The Roxo reservoir is one of those will receive water from Alqueva in 2016. The increase of water in quantitative and qualitative terms can provide very significant increases in the growth of the soil production that we must monetize in the best way. The aim of this study was evaluate the quality of water resulting from the monitoring carried out during 2014/2015 in the hydraulic system and in the drainage network of the irrigation perimeter of Roxo's reservoir to be made a more sustainable management of irrigated area. The main conclusions were as follows: i) the water of the irrigation channel and drainage network show a mil to moderate degree of salinity risk; ii) doesn t show characteristics to modify the soil infiltration conditions; iii) indicates degree of restriction slight to moderate due to the amounts of Na+ and Cl-; iv) the drainage network presents toxicity due the chlorides and boron; v) the ammonia nitrogen and nitrate values were low. The application of nitrogenous fertilizers seems to influence the results