Globally, there is a dire need for a new class of advanced non-sewered sanitation systems (NSSS) to provide onsite wastewater treatment that is capable of meeting stringent discharge or reuse criteria. These systems need to be simple to operate and maintain, reliable, and resilient to unreliable electrical service. The NEWgenerator (NG) is a compact, automated, solar-powered wastewater treatment system comprised of three major treatment processes: anaerobic membrane bioreactor (AnMBR), nutrient capture system (NCS) with ion exchange and carbon sorption, and electrochlorination (EC). The NG system operated at an informal settlement community in South Africa over a 534 d period, treating high-strength blackwater (BW) and yellow water (YW) from a public toilet facility. Over three test stages (BW, BW + YW, BW) that included several periods of dormancy, the NG system was able to provide a high level of removal of total suspended solids (97.6 ± 3.1%), chemical oxygen demand (94.5 ± 5.0%), turbidity (96.3 ± 9.7%), color (92.0 ± 10.5%), total nitrogen (82.1 ± 24.0%), total phosphorus (43.0 ± 22.1%), E. coli (7.4 ± 1.5 LRV, not detected in effluent), and helminth ova (not detected in effluent). The treatment levels met most of the ISO 30500 NSSS standard for liquid effluent and local water reuse criteria. A series of maintenance events were successfully conducted onsite over the 534 d field trial: two membrane cleanings, two NCS regenerations, and granular activated carbon replacement. Desludging, a major pain point for onsite sanitation systems, was unnecessary during the field trial and thereby not performed. The AnMBR performed well, removing 94.5 ± 5.0% of the influent COD across all three stages. The high COD removal rate is attributed to the sub-micron separation provided by the ultrafiltration membrane. The NCS was highly efficient at removing total nitrogen, residual COD and color, but the regeneration process was lengthy and is a topic of ongoing research. The EC provided effective disinfection, but frequent prolonged run cycles due to power supply and water quality issues upstream limited the overall system hydraulic throughput. This extended field trial under actual ambient conditions successfully demonstrated the feasibility of using advanced NSSS to address the global water and sanitation crises.
The Engineering Field Testing Platform (EFTP) was designed to provide an opportunity for technology developers (TDs) to test non-sewered sanitation prototypes in the eThekwini Municipal Area (Durban), South Africa. Between 2017 and 2020, 15 sanitation systems were tested in informal settlements, peri-urban households, and other ‘real world’ settings. This paper illustrates the lessons learned from establishing and managing this testing platform. Costs and timelines for testing are dependent on several factors, including the aims of testing, the development stage of the prototype, whether testing takes place in a community or household setting and if a testing site is shared between prototypes. Timelines were routinely underestimated, particularly for community engagement and commissioning of prototypes to reach steady-state operation. Personnel accounted for more than half of the EFTP’s costs. The presence of the municipality as a platform partner was vital to the success of testing, both for gaining political support and for enabling access to testing sites. It is noted that working in communities, with test sites in public spaces, requires technical and social sensitivity to context. It was important to ensure testing supported future municipal decision-making on service provision, as well as longer-term development within communities. The high number of stakeholders, locally and internationally, raised management challenges common to any large project. However, the EFTP added value to TDs, the eThekwini Municipality, and communities requiring improved sanitation services; this was amplified through the platform approach.
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