天美传媒

Abstract

Current urban wastewater (UWW) treatment technologies developed decades ago for meeting the mandatory discharge regulations to protect receiving waters and public health are now seen as unsustainable because of continued reliance on fossil fuel-derived energy to operate them. In addition, these technologies dissipate valuable energy, carbon, and nutrient content of the wastewaters to the environment. For example, UWWs contain internal energy of about 6.3-7.6 kJ/L, which is about 2-3 times the energy that is currently used for treating them. UWWs contain ammonia of about 40 mg/L which is converted by current technologies to gaseous nitrogen and discharged into the atmosphere, instead of harvesting it for use as fertilizers. In this paper, we report on a single-step algal system based on mixotrophic metabolism for simultaneous removal of carbon and nutrients from UWWs. The specific advantage of the mixotrophic system over the traditional heterotrophic bacteria-based systems stems from the fact that stoichiometric carbon-to-nitrogen (C:N) ratio in UWW is closer to that of algal biomass composition than to that of heterotrophic bacteria. This paper includes BOD and nutrient removal by Galdieria sulphuraria from UWW and an energetic analysis to show that the proposed approach can yield more than double the net electrical energy than the traditional heterotrophic bacterial based system. Based on the experimental results, an integrated system for sustainable urban wastewater treatment system capable of net energy production and net fertilizer production is presented.

Biography

Najla Abdul Rahman AL-Meshhen has completed her PhD at the age of 42 years from Dammam University and postdoctoral studies from Dammam University. She is Assistant Professor, Member of various committees in the Department of biology. .

Email: naalmeshhen@ud.edu.sa