Design and cost evaluation of anaerobic bioreactor for industrial waste

Abstract

Industrial wastewater with very high Total Organic Carbon (TOC) is a potential substrate for anaerobic treatment. Continuous Flow Stirred Tank Reactor (CSTR) is the common model of reactor used to treat various kind of wastewater. Development and modification on digester type is still ongoing till this day. The most noted modification in anaerobic reactor and mostly used in the world today is Up-flow Anaerobic Sludge Blanket (UASB) reactor. The main focus of this study is on calculating the design that suitable for treating glycol and organic acid based industrial wastewater. The wastewater is predicted to have total Chemical Oxygen Demand (COD) of 50 kgCOD/m3 to 100 kgCOD/ m3 and wide range of salinity. Two models of anaerobic reactor were compared and their parameters calculated based on initial data of the wastewater, Anaerobic Contact reactor and UASB reactor. Influent COD total is assumed to be pre-treated to remove particulate COD, thus COD inlet has nearly 100 % soluble COD. The influent COD is set at 70 kgCOD/m3 and flow rate of wastewater at 150 m3/d. Two digester tanks were calculated for Anaerobic Contact reactor, where Acid phase tank has 1526 m3 volume and Gas phase tank has 5941 m3. The UASB reactor was split into 4 unit tanks with digester volume at 636 m3. An external recirculation pump is required to control the up-flow velocity of the UASB. Both of the anaerobic models are predicted to have daily maximum methane production at 4130 m3/day with energy production rate of 131.3 GJ/day. Costs of the biogas construction were calculated based on its constituent materials. The estimated cost of equipment generation for Anaerobic Contact digester and UASB is 17,237,528.90 Kr and 7,907,535.00 Kr, respectively. The Anaerobic Contact reactor becomes the feasible model for treating the industrial wastewater with high COD concentration based on its ability to withstand shock of wastewater load.