The performance of AGS reactors treating municipal wastewater can be optimised by converting influent particulate matter into readily available substrate. This can be done via anaerobic hydrolysis and fermentation of the influent. Anaerobic processes taking place in pressure sewers are not fully understood but show the potential to act as a pre-treatment for the wastewater reaching AGS reactors. Moreover, the contribution of the influent to the hydrolytic activity of the reactor is unknown. This research evaluated the impact of a pressure sewer on wastewater characteristics, as a possible pre-treatment of sewage before reaching the treatment plant. The variations of sewage in terms of physicochemical composition and microbial activity were monitored in a full-scale pressure sewer, focusing on the hydrolysis and fermentation of organic matter for further treatment in AGS reactors. Moreover, the contribution of the influent to the enzymatic activity of a full-scale AGS reactor was assessed. Inaccuracies deriving from sampling on a full-scale pressure sewer might have affected the results. However, statistical analyses helped to derive trends from the collected data. The pressure sewer primarily affected the degree of fermentation of the wastewater and the concentration of suspended solids. It is hypothesised that such variations could benefit the performance of AGS reactors. Although the biodegradability and enzymatic activity of the wastewater did not improve significantly, anaerobic conveyance seemed more appropriate than aerobic transport for AGS reactors. However, the influent did not seem to have a large contribution to the total reactor activity, due to the high concentration of granular biomass.

Delhi is facing a very rapid urbanization, making it difficult to keep up with the construction of sewerage and water treatment infrastructure. The LOTUSHR project was created to research alternative solutions to treat mixed water streams and prevent pollution flows from urban drains into the environment. Biofiltration was identified as a suitable on-site sanitation alternative to provide adequate water quality and hygienic conditions. In particular, this work is intended as a first step in the future design of the biofilter, by investigating the potential of hydrophilic mineralwool as a filtering medium for the Barapullah drain contaminated water. Mineralwool performance was tested, focusing on nutrients and heavy metals removal. The effect of different HRT’s on biofilm formation was evaluated and the minimum length for optimal filter performance was researched. The fieldwork was conducted in Delhi between the 4th January and 9th February 2018. Four mineralwool filters were monitored, running with different operational parameters under the same environmental conditions. Biological activity was identified as a key factor in increasing the removals of COD and NH3-N. Bare mineralwool achieved PO4-P reduction, independently from the presence of a biofilm. Moreover, a shorter HRT determined a selection pressure for attached biomass growth, leading to a more swift biofilm formation. Unfortunately, part of the obtained results showed a high error margin. Possible reasons for these error margins are discussed. Hydrophilic mineralwool is an emerging material and not much research is yet available on its water filtering properties. This thesis suggests that mineralwool can be used as a pre-treatment step in the sanitation of polluted drains in rapidly urbanizing megacities.