This is a water-based sewer system in which Blackwater is transported to a Centralized or Semi-Centralized Treatment facility. The important characteristic of this system is that there is no Collection and Storage/ Treatment. Inputs to the system include Faeces, Urine, Flushwater, Anal Cleansing Water, Dry Cleansing Materials, Greywater and possibly Stormwater.
There are two User Interface technologies that can be used for this system: a [[Pour Flush Toilet | Pour Flush Toilet]] (U.4) or a [[Cistern Flush Toilet | Cistern Flush Toilet ]] (U.5). A [[Urinal |Urinal]] (U.3) could additionally be used. The Blackwater that is generated at the User Interface together with Greywater is directly conveyed to a (Semi-) Centralized Treatment facility through a Simplified (C.4) or a [[Conventional Gravity Sewer | Conventional Gravity Sewer network ]] (C.6).
Stormwater could also be put into the Gravity Sewer network, although this would dilute the wastewater and require Stormwater overflows. Therefore, local retention and infiltration of Stormwater or a separate drainage system for rainwater are the recommended approaches.
A combination of the technologies T.1-T.12 is required for the treatment of the transported Blackwater. The Sludge generated from these technologies must be further treated in a dedicated Sludge treatment facility (technologies T.13-T.17) prior to Use and/or Disposal.
Options for the Use and/or Disposal of the treated Effluent include [[Irrigation | Irrigation]] (D.6), [[Aquaculture Ponds | Fish Ponds ]] (D.9), [[Floating Plant (Macrophyte) Pond | Floating Plant Ponds ]] (D.10) or discharge to a water body ([[Water Disposal - Groundwater Recharge | Water Disposal/Groundwater Recharge]], D.11). After adequate treatment, Sludge can either be used in agriculture (D.5) or brought to a Storage/Disposal site (D.12).
===Considerations===
