Biological Application of MEMS Microelectrode Sensors for Direct Measurement of Phosphate in the Enhanced Biological Phosphorous Removal Process

The determination of phosphate has been of great importance in the fields of clinical, environmental and horticultural analysis for over three decades. New cobalt-based Micro Electro Mechanical Systems (MEMS) microelectrode array (MEA) sensors for direct measurement of phosphate in small environmental samples such as microbial aggregates has been introduced and applied here for in situ measurement of phosphate within activated sludge flocs in the enhanced phosphorus removal process (EBPR). MEMS technologies offer the advantages of accurate fabrication methods, reduced complexity of the fabrication process, mass production, low cost, and increased reliability. Well-defined phosphate profiles across the flocs were observed under anaerobic conditions, during which phosphate was released from the flocs, using the MEMS MEA sensor. The microprofiles were compared with the microprofiles measured using conventional phosphate microelectrodes. The developed MEMS MEA sensors were useful tools for the in situ measurement of phosphate in small aggregates.