IWA 28:2018 specifies requirements and test methods to ensure safety, performance and sustainability of community-scale resource-oriented faecal sludge treatment units that serve approximately 1 000 to 100 000 people. IWA 28:2018 applies to treatment units that:
· primarily treat faecal sludge;
· are able to operate in non-sewered and off-grid environments;
· are prefabricated.
IWA 28:2018 does not apply to sanitation treatment units requiring sewer infrastructure, or to those requiring electric grid access during steady state operation.
Treatment units to which IWA 28:2018 applies exhibit resource recovery capability (e.g. recovering energy, reusable water, soil amendment) and are capable of being energy neutral or energy net positive.