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AUTOMONOUS MICROLABORATORIES for phosphorus and nitrogen monitoring in natural waters and wastewaters

Grant number: 09/08486-4
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): December 01, 2009
Effective date (End): November 30, 2012
Field of knowledge:Engineering - Electrical Engineering
Principal Investigator:Antonio Carlos Seabra
Grantee:Zaira Mendes da Rocha
Home Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil


In recent years a rapid deterioration of water quality is underway, as a result, among other reasons, of increasing amount of effluent discharges into water bodies. The concentration control and effective pollutants removal, particularly of the nutrients nitrogen and phosphorus, is of vital importance in effective water pollution control. This research project aims to investigate and develop fully Autonomous MicroLaboratories (AML), containing microfluidic channels and mixers built inside electronic ceramic substrates, integrated with electronic driving and control circuitry for chemical detection. These autonomous microlaboratories will be applied to the determination of phosphorus and nitrogen levels in effluents of wastewater treatment plants according to analytical chemistry procedures described in the Standard Methods and techniques like: flow injection analysis (FIA), stopped-flow and binary sampling.This research project will be based on candidate's previous doctoral work, in which a central part of a micro-FIA photometric analyzer to determine phosphorus concentration was developed using low temperature co-fired ceramics (LTCC), a versatile material that allows rapid prototyping of microchannel, micromixers and the implementation of electronic circuits on it. The developed device has proven successfully the proposed concept; however, many issues should be addressed in order to achieve an autonomous system. The candidate will make an in-depth study of the AML concept for determination of nitrates and nitrites, which presents technical challenges not investigated in the PhD, and to improve detection limits for phosphorus in water according to Brazilian legislation (0.025 mgPl-1). The autonomous multiparametric microlaboratory will use a set of mini-solenoid valves and micro-peristaltic pumps controlled electronically, thus allowing to obtain real-time concentrations of phosphorus and nitrogen without the need for intensive trained staff to monitor the procedure. The effects of characteristics such as mixer and flow cell size, electronic aspects as acquisition time and signal filtering, reaction time and detection technique (FIA, stopped flow and multicommutation) will be addressed.Through a partnership with Sabesp (under negotiation), the implantation of AML to the analysis of effluents in wastewater treatment plants will be evaluated, intending to improve the process of phosphorus and nitrogen removal to the tertiary level of treatment by controlling the amount of chemical reagents to be added into water according to measured levels of phosphorus and nitrogen. Since this is a real case study, new solutions for sample filtering and the reduction of interfering effects will be also studied. This study should have a direct impact on the processes of phosphorus and nitrogen removal and could lead to the economy of millions of dollars on unnecessary consumption of chemicals products.

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
DA ROCHA, ZAIRA M.; MARTINEZ-CISNEROS, CYNTHIA S.; SEABRA, ANTONIO C.; VALDES, FRANCISCO; GONGORA-RUBIO, MARIO R.; ALONSO-CHAMARRO, JULIAN. Compact and autonomous multiwavelength microanalyzer for in-line and in situ colorimetric determinations. LAB ON A CHIP, v. 12, n. 1, p. 109-117, 2012. Web of Science Citations: 15.

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