No abstract

In this study, the process and utility water requirements for cellulosic ethanol production via fermentation pathway were assessed on a volume‐to‐volume basis (i.e., gallons of water consumption per gallon of ethanol production) using the data reported in the literature. The water requirements were analyzed for a combination of three feedstocks (i.e., hardwood, corn stover, and switchgrass) and two pretreatment technologies (i.e., dilute acid and ammonia fiber expansion) under different water network configurations aiming for zero wastewater discharge. The results indicate that the process water requirement is significantly dependent on the selection of a pretreatment process and a feedstock, while the effective design and operation of a cooling tower offers an opportunity for saving utility water. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 396‐405, 2013

Chlorella vulgaris is known as one of the fastest growing microalgae, and is used in this study for the removal of residual ammonia (NH 3 )/ ammonium ion (NH 4 + ) present in the wastewater effluent collected from a local wastewater treatment plant, Mill Creek plant in Cincinnati, OH. The wastewater effluent contained 8.05 ± 0.16 mg/L of nitrogen concentration in the form of ammonia/ ammonium ion, 50.18 ± 0.82 mg/L of total inorganic carbon concentration, and 1.84 ± 0.10 mg/L of orthophosphate concentration at pH 7.34 ± 0.05. This study demonstrates that Chlorella vulgaris has the capability to diminish nitrogen concentration in a form of ammonia/ ammonium ion during its growth while also consuming total inorganic carbon concentration. The Monod equation is used to describe its kinetics for growth and stationary phases using nitrogen as a limiting substrate.