Side-stream membrane-based NH3 extraction to improve the anaerobic digestion of poultry manure

Abstract

The influence of membrane-based ammonia extraction on poultry manure (PM) wastewater treatment was assessed in a 3 L continuous stirred tank reactor (CSTR). The anaerobic digester operated for 91 days at a hydraulic retention time of 15 days and 37 °C. The flat sheet polytetrafluoroethylene (PTFE) membrane module was interconnected to the CSTR and operated at a recirculation flow rate of 0.25 L min−1. The membrane-based ammonia extraction mediated a decrease of total ammonia nitrogen of 64.5 % and of total nitrogen of 53.4 %, which induced an increase in the methane yields from 360 ± 70 up to 574 ± 5 N mL CH4 g VS fed−1. Similarly, chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies increased from 59 % ± 2 % and 57 % ± 3 % up to 79.1 % ± 0.8 % and 65.8 % ± 0.2 %, respectively. This work targeted the enhancement of the performance of full-scale anaerobic digestion plants via reduction of NH3 concentration with a membrane-based extraction unit.