Wastewater Treatment

A key societal service, wastewater treatment is transforming from waste remediation to used resource recovery

PictureWastewater treatment provides an essential service by removing contaminants from water prior to discharge to streams, lakes, or other receiving waters.  Traditional wastewater treatment requires large amounts of energy and produces biosolids that require incineration or disposal.  We are developing new technologies to improve wastewater treatment plant sustainability and performance.  We work with industry leaders to develop new technologies that allow energy and nutrient recovery, thus making wastewater treatment a resource producer, not a resource consumer.  One specific target is increasing the rate of hydrolysis of organic solids, which converts the solids into much more bioavailable soluble forms.  Increasing hydrolysis results in more available substrate for microorganisms to produce renewable energy, such as methane (CH4) or hydrogen (H2).  It also frees up soluble ammonium (NH4+) and phosphate (PO43-) that can be recovered and turned into renewable fertilizers.  Our research involves means to increase hydrolysis by pretreating the solids and methods to capture the energy and nutrients into forms useful in modern society.

Key to our efforts to transform wastewater treatment plants to be more sustainable is mathematical modeling.  Modeling different wastewater treatment configurations allows us to identify how different configurations affect energy production and consumption, biosolids production, and the fate of nutrients.  In particularly we developed the Combined Activated Sludge Anaerobic Digestion Model (CASADM), which links anaerobic digestion and activated sludge models into one interface.  CASADM allows us to gain insights into how to maximize CH4 capture for energy and reduce biosolids production while reducing greenhouse gas emissions like CH4 and CO2.

A model of the Siemens Water Technologies hybrid process determined that recycling anaerobic digester sludge through the activated sludge process increases biomass retention time, improving hydrolysis and increasing methane production in the anaerobic digester