Final technical report Project OPP1164143 – Characterization of faecal material behaviour during drying
Creators: name: Stringel, Santiago Septien
Publisher: name: Gates Open Research
Year: 2020

description: This document is the final technical report from the project OPP164143, entitled "Characterization of faecal material behavior during drying".<br><br>EXECUTIVE SUMMARY<br>Drying is a relevant unit operation during faecal sludge and fresh faeces treatment. It allows the removal of moisture from the faecal matter and its disinfection, so making it safer to handle, easier to transport and a more suitable biofuel. The Pollution Research Group (PRG), at the University of KwaZulu-Natal (UKZN), received a grant from the Bill &amp; Melinda Gates Foundation through the OPP1164143 to investigate the drying of faecal materials (faecal sludge from onsite sanitation facilities and fresh faeces). The objectives of this research were to generate useful insight and data to overcome the current technological gaps from faecal wastes drying. This research project, done in collaboration with Swansea University and Cranfield University.<br>This research project was divided into three distinct phases: (i) a landscape study, (ii) experimental work, (iii) and dissemination of knowledge and data. The landscape study was conducted to identify the gaps in the drying technologies and the areas of greatest interest to explore through research. The experimental planning was based on the outcomes from the landscape study, and different kinds of experiments were carried in the three institutions. The next step was to disseminate the data and knowledge generated from this project, as well as data collected from previous projects and partner institutions.<br>The objectives from the experimental work included topics as: drying kinetics, heat of drying, boundedness of the moisture in the faecal material, thermal degradation, pathogens deactivation, physiochemical properties, morphological characteristics, boundedness of the moisture, odours. The experimental work from this project was carried out in three different geographical locations: PRG-UKZN, Cranfield University and Swansea University. The experiments were conducted using faecal sludge collected from on-site sanitation facilities from the eThekwini municipality (faecal sludge from ventilated pit latrines, urine-diverting dry toilets and an anaerobic baffled reactor from a decentralized water treatment system), as well as fresh Human faeces from donations at PRG-UKZN and Cranfield University. The faecal sludge samples from on-site sanitation facilities were exported to the United Kingdom (UK) for their testing at Cranfield University and Swansea University. The experimental work included the following analysis: thermogravimetry, thermal analysis, gas analysis, spectrophotometry, calorimetry, proximate composition analysis, CNS analysis, rheometry, dewatering, sorption isotherms, water activity analysis, thermal properties analysis, specific surface analysis, particle size distribution analysis, qualitative observations.<br>The outcomes from this research project highlight the importance of temperature on the drying kinetics and disinfection of the faecal matter. Moreover, the moisture boundedness at the different stages from the drying process was characterized and related to the variation of the faecal matter consistency, energy consumption, thermal properties and pathogens deactivation. Furthermore, the different types of faecal material were compared in terms of their drying and dewatering capabilities, and moisture boundedness. In addition to this, interesting results were obtained concerning the thermodynamic equilibrium of the process, properties of the dried solid, the suitability of radiative methods to dry faecal matter and the odour emission.