Abstract
One of the biggest challenges to overcome in WWTPs in developing countries is the reduction of energy
consumption, and optimization of the different processes and services at the facility. This challenge could be reached
by implementing a pre-treatment of sludge and a two-stage anaerobic digestion for increases the yield of hydrogen
(H2) and methane (CH4) as source of green energy (GE). A pre-treatment should selectively inhibit methanogenic
bacteria and increase the production of acetic acid and acetate, thus achieve the highest possible H2 yield.
Furthermore, several techniques have been appointed as potential pre-treatments due to their simplicity, contribution
to hydrolysis of organic material presented in the biomass. Moreover, H2 has the highest energy content per unit
weight of any known fuel (120.21 MJ/kg). This is particularly interesting, as there are additional socio-economic
benefits for using bio-H2 as a source of energy. Therefore the production and in-situ used of GE in WWTP is turning
into the eye of many companies in developed countries, where Biosolid are normally disposed or used as soil
amendment. This study focused in two main topics: 1) Four pre-treatments: temperature shock, pH control, chemical
addition and a combination of the above mentioned and 2) Real Case Study (Switzerland), where a selected pretreatment
was implemented for enhancing H2 and CH4 production. Therefore, the aims of this research were: a) To
study the influence of different pre-treatments on the 1st stage of a two-stage AD; b)To select the most suitable pretreatment
for enhancing the bio-H2 production for scaling-up; c) Perform and energy balance for justifying the energy
neutrality of the process in a real case WWTP.