A Float Meter Based System for Self-Regulated Discharging and Feeding in a Laboratory Semi-CSTR for Anaerobic Digestion of Chicken Litter

Abstract

HighlightsA float meter based system (FMBS) was designed for self-regulated discharging and feeding in an anaerobic semi-CSTR.The accuracy and feasibility of the FMBS were determined for anaerobic digestion of chicken litter.The FMBS had the advantages of much lower cost and better full working volume control than a digital accurate pump system (DAPS).Abstract. Given the rapidly rising costs in building lab-scale reactors, efforts are needed to examine innovative designs of reactor systems to reduce the expenses of scientific research. In this study, a float meter based system (FMBS) was designed for self-regulated discharging and feeding to operate a semi-CSTR for anaerobic digestion of chicken litter (CL) with wheat straw (WS). The FMBS functioned properly in following a feeding, reaction (stirring), settling, and discharging cycle based on the hydraulic retention time (HRT). However, clogging in the feeding or discharging lines of the reactor might occur for co-digestion of CL and WS with high TS content (C/N = 20, TS = 6%). Compared with a digital accurate pump system (DAPS), the FMBS showed the advantages of low cost ($182 << $6000) and better control of the full working volume. The longest HRT that could be achieved in this study with an exchange liquid volume of 2 L in each operating cycle was 100.7 h. In all, the FMBS design could serve as a low-cost option for designing lab-scale, semi-CSTR for anaerobic digestion as well as other reactor configurations. Keywords: Anaerobic semi-CSTR, Feeding and discharging, Float meter, Self-regulated.