This research addresses the critical issue of the poor implementation of sanitation and its effect on community and environmental health in the Global South. To overcome the social, cultural, technical, and financial complexities underlying poor sanitation, the participation of local community members in sanitation planning processes is deemed crucial for the successful development and implementation of sanitation systems.
To engage local stakeholders as decision-makers and improve design freedom, it is proposed to engage stakeholders in determining their demands, needs, and priorities by combining the Fuzzy Analytical Hierarchy Process (FAHP) and Focus Group Discussions (FGD) as a participatory decision-making method. The applicability and suitability of this method are assessed through a case study in Hagonoy, the Philippines, in which two parallel design cycles are carried out: one with only local sanitation experts as decision-makers and one with only local community members as decision-makers. A systematic literature review of design criteria applicable to sanitation design processes was conducted to overcome selectors' bias regarding the decision criteria assessed in the FAHP and the FGD. The FAHP data was collected among 60 community members evenly distributed over six neighbourhoods in Hagonoy and six local sanitation experts. Three FGDs were held with local community members, whilst one FGD was held with local sanitation experts. The design cycle based on the defined design scope was limited to the development of a conceptual design, proposing a treatment train capable of treating the produced domestic wastewater such that the effluent satisfies the local General Effluent Standards, specifically for the parameters water volume, Total Phosphorus (TP), Chemical Oxygen Demand (COD), Ammonia (NH3), and Nitrate (NO32-). Wastewater treatment technologies aligning with the demands and needs specified by the stakeholders were obtained from scientific literature, which were combined into a sanitation system configuration that could treat the water sufficiently.
The completion of a sanitation design process without predefining the possible solutions, but by integrating the FAHP + FGD in the systematic derivation of the design scope, demonstrated how a demand- and need-driven design approach allows increased flexibility and sensitivity for the context in the development of a design. The parallel design cycles showed how the FAHP + FGD method could be applied as a systematic procedure to understand how design criteria in sanitation design are preferred and interpreted differently between local community members and local sanitation experts and how this can influence the conceptual design. Altogether, this research contributes to the body of knowledge in community-engaged sanitation design by demonstrating the effectiveness of the FAHP and FGD method in engaging community members in a need-driven design process, overcoming selectors’ bias for technologies and trade-offs, and producing relevant design proposals. However, acknowledging that the FAHP + FGD method was limited to engaging stakeholders only in defining the needs and demands, verification of the designs’ alignment with the perspectives of stakeholders and continuous engagement throughout the entire design process is essential to be further researched in the future.

The scarcity of water is a major global concern in the modern times. Hence, the judicial use of water must be coupled with water reuse to counteract the water depletion. To reuse water, we eye on available treatment technologies which can guide us to circular use and reuse of water and nutrients. Anaerobic digestion, is known for producing better quality effluent with a possibility of energy generation through biogas. It can also be coupled with post-treatment techniques to extract nutrients. Anaerobic membrane bioreactors have been used to treat high-strength wastewater to obtain higher particle and organic removal. Introducing limited aeration to such an anaerobic environments have been studied earlier to enhance the degradation process. Depending on the quantity of aeration added and the mechanism of aeration, studies have reported both positive and negative effects on the organic degradation. The existing studies only cover the effects of the applied aeration on the Anaerobic Digestion process. Little is talked about its effect on the sludge characteristics such as particle size and sludge rheology. This research focuses on studying the effect of applied aeration on the AnMBR performance, based on the effect of aeration on substrate degradation and on sludge characteristics. To study this, an AnMBR is operated with laboratory-made synthetic blackwater treating 5gCOD/l. A 2% increase in oxygen with respect to the sludge VSS is introduced through added air. The effect of this added aeration to the system is studied. The organic removal was enhanced by 11% when compared to the observed removal during the non-aerated phase. Ammonium concentration increased by 24% and sulphate concentration reduced by 12% in the effluent. The size of the coarser fraction of sludge, D90 increased by 13% and that of the finer fraction D10 increased by 15%. The viscosity profile of the sludge after aeration also increased. Inhibition caused to the Methanogenic activity of the sludge reduced as the sludge started adapting to the applied aeration. Activity changes to higher sets of aeration matching that of a Dissolved Aeration and Flotation system was studied. The feasibility of such a system is still a work in progress for the future. The obtained results are for an adapting sludge, and has to be continued for a better adapted sludge. Recommendations based on this study to future works on the same line, is given.

Dissolved air flotation (DAF) is a water treatment technology meant for the separation of suspended particles from the water. Since the fifties of the XIX century, it has gained an important role in many sectors of water treatment applications. In general, the flux variability, the small space requirement, and the limited energy consumption excel as some of the most relevant advantages of the DAF system. However, because of its not always excellent removal efficiency, DAF applications are usually considered as pre-treatment technologies to reduce the particles' load from more effective technologies as sand or membrane filtration technologies. Briefly, the amelioration of the suspended solids' separation is of particular interest because it decreases the maintenance cost of the next filtration units and, in some cases, it might substitute them. Coagulation and flocculation processes prove to be of extreme importance for the DAF performance as it is characterized by particles cut-off around 1-10 μm. The purpose of this research was the application of extra-polymeric substances (EPS) as a flocculant to enlarge the floc dimension of an anaerobic digested sludge and improve DAF efficiency. In the literature the flocculation ability of EPS is not completely acknowledged, but there are some succesfully results with microalgae and activated sludge. Specifically, the feasibility of producing EPS directly on-site, is interesting because it makes the treatment plant possibly independent from the flocculant purchase. Moreover, an extra amount of EPS might be sold (1$/kg) or used for the production of other valuable products (e.g. biodiesel production).
In collaboration with the Water Lab at the faculty of Civil Engineering in Delft and Royal Haskoning (DHV), it was possible to perform some experiments to understand the flocculation properties of EPS in the dissolved air flotation technologies. More specifically, the effects of the EPS were studied with two experiments: a jar test and a flotation column experiment. The sludge used for the experiment was collected from Harnashpolder facility after being digested for at least 25 days. With the jar test experiments, it was examined the effects of sludge settleability (5 gTSS/L): increasing EPS doses (200-1200 mgEPS/L), increment by 20% the original SVI value, on average. Furthermore, it was performed a small scale flotation experiment with two Alka seltzer pills. After a certain EPS dose (400 mgEPS/L), TSS in the formed foam resulted 1.78 times more concentrated. Finally, it was also analysed the particle size distribution (PSD) variation, but the measurements were characterized by a high standard deviation which reduced the reliability of the results. The scope of these first experiments was the individuation of a certain EPS dose to apply in the flotation column experiment simulating the DAF performance (800 mgEPS/L). The EPS addition did not improve the quality of the effluent (65%), and was slightly inferior to the blank series (69%). However, the obtained foam was almost 1.75 times more concentrated when compared to the blank solution. Towards the end of the experiment, a better removal efficiency was notated within the EPS series and it was correlated to the foam concentration (R2= 0.989). Despite the errors, PSD of the EPS series were characterized by a higher frequency of small particles, between 1-10 μm. In the discussion chapter two explanations are proposed considering the effect of zeta potential variations after the EPS addition. In conclusion, the use of EPS to enhance the solid-liquid separation of the sludge was not successful. However, further research with different doses of EPS and different types of sludge should be studied to assess the potential use of EPS to improve the efficiency of a DAF system.

To cope up with the rapid industrialization, urbanization and population it is very important to make use of sustainable water treatment technologies to reuse the processed water. Now a days, with technological advancements in anaerobic digestion (AD) process it is possible to recover some of the resources. AD can be coupled with the membrane to provide the complete biomass retention ensuring the growth of slow growing bacteria. Considering these aspects an innovative configuration of Anaerobic Membrane Bioreactor (AnMBR) with limited aeration is developed aiming to improve the reactor performance. This AnMBR is tested, comparing its performance before and after aeration to assess the impact of subjected aeration especially on the activity of methanogens monitoring the biogas production and its composition. Results show that limited aeration helped in achieving significantly lower overall COD removal without adversely affecting the biogas production as well as composition. It also improved the biodegradability of less biodegradable ovalbumin (protein).Furthermore, limited aeration might improve the biotransformation of some of the recalcitrant micropollutants (MPs) possibly by activating mono-oxygenase enzymes of micro-organisms. They might convert the aromatic hydrocarbons into less recalcitrant phenolic intermediates, whose degradation process could occur anaerobically. From the group of available MPs, diclofenac (DCF), metoprolol (MPT), sulphamethoxazole (SMX), trimethorprim (TMP) are selected based on different characteristics. All the selected MPs are analysed for their removal through biodegradation and adsorption under anaerobic conditions. MPs are tested from liquid phase in dissolved form through liquid chromatography coupled with mass spectroscopy (LC-MS) technique while MPs sorbed onto the sludge surface are not analysed because of complex extraction process.Results shows that SMX and TMP are removed more than 99% through AD while DCF is removed with removal efficiency of more than 90%. Adsorption is found to be a major contributor for the removal of DCF, MPT and TMP while SMX is mainly removed through biodegradation. DCF and TMP are adsorbed well (>90%) compared to SMX and MPT (around 30%) onto the sludge contributing to overall removal. Octanol water coefficient (Kow) which defines the hydrophobicity of compound, is the key parameter deciding the extent of adsorption. Additionally, sludge retention time (SRT) and compound structure play major role in deciding the fate of MPs through biodegradation. Different aerations had not shown any significant impact on the removal of DCF, SMX and TMP. While in case of metoprolol effect of aeration was not completely understood. Considering the overall removal, DCF was found to be bio-degraded more with increased concentration. Granular activated carbon (GAC) used for adsorption removed all the four MPs with more than 90% efficiency. Further studies can be conducted on possibilities of adding GAC to the reactor so that they get adsorbed and later on degraded.

Anaerobic wastewater treatment is a preferred attractive treatment mainly because of its simplicity and compactness as it produces lesser sludge compared to the aerobic system. Despite this, it has its own disadvantages as it takes more time for bacterial growth and treatment and also contributes to nutrients such as N and P to the effluent. Anaerobic digestion can be divided into four categories namely hydrolysis, acetogenesis, acidogenesis and methanogenesis. Hydrolysis is generally the rate limiting step of an anaerobic digestion. Studies show that hydrolysis is faster in aerobic process than in anaerobic process. Hence, hydrolysis may be fastened by supplying air. But oxygen inhibits the growth of strong anaerobes in the later stages of anaerobic digestion mainly affecting methanogenesis. This study focusses on studying the removal of organics by using 0.05vvm air into the filtration part of an 8-litre side-stream AnMBR with a fly ash membrane filter module. The result thus obtained is compared with a 100-litre AnMBR of similar construction without any air. The study observed a higher removal of COD in the aerated system than the non-aerated system.