India City Archetype: Steady Roller 0.1–1 million people, 20–40% coverage, high number of septic tanks1

Consider co-treatment: improvement of existing Yes or planned STPs to treat Do existing or planned FS. Also consider G-OP for STPs have extra treatment. capacity to treat FS?

No Assumptions 1 Analysis is based on cost comparison at a Consider ~200K-240K fecal management (FSM) adopting FSM reliant population equivalent. Depending on specific population needs, multiple/distributed SCWO-OP or P-OP systems may be required. Note that STeP’s “Market Insights for the ” report indicates that decision makers may Is land availability Consider P-OP, consider ease-of-operation when selecting a Yes a constraint?2 SCWO-OP, or FS-4 FSM system for this city archetype. However, this factor is not considered in the decision No tree, because ease-of-operation issues are assumed to be easily addressed via training or

3 hiring. See second page for FSM system Are land prices high? Yes Consider FS-4 descriptions. STP stands for plant, and FS stands for fecal sludge. Other No acronyms are explained on the second page. 2 For example, is <2 hectares of land available Are you considering Consider Yes for a fecal sludge treatment plant (FSTP)? co-treatment of MSW? G-OP 3 For example, does the land available for the FSTP cost Rs 39,400/m2 or more? Note that all No remaining questions in the decision tree assume low land prices (e.g., ~Rs 3,150/m2). Is water reclamation Consider P-OP, Yes 4 a primary driver? SCWO-OP, or FS-4 FS-1 and FS-4 represent the lowest-cost solutions for this scenario when prices are less than Rs 1.5/kg. No

Do you value the Consider Yes production of compost? FS-2 or FS-3

No

Do you value complete pathogen destruction Consider P-OP or Yes in solids produced by SCWO-OP your FSTP?

No

Consider FS-1 or FS-44

Disclaimer: This decision tree is based on market information collected for India, as well as cost-modeling for common types of systems that may be constructed there. It is designed to provide high-level, directional guidance for decision makers. It is not intended to take the place of a detailed feasibility assessment for a specific project. Actual life cycle costs for any system are driven by many localized factors. It is therefore recommended that cities conduct a life cycle analysis that is location-specific when making cost-based decisions on system alternatives. For more information on assumptions used to create this tool, see "STeP Market Insights for the Omni Processor" and "STeP Techno-Economic Analysis (TEA) of Model Fecal-Sludge Management and Sewer-Based Systems in India”. We would like to thank professor Srinivas Chary of the Administrative Staff College of India for his inputs to this work (www.asci.org). Model system: FS-1 Model system: FS-2 Discharge Co-composting (Windrow) Land Apply Vacuum tanker Manual Screen Sludge Bed (unplanted with roof) Vacuum tanker Manual Screen Sludge Drying Bed (unplanted with roof) LEGEND LEGEND Discharge Fecal sludge Fecal sludge Discharge Liquids Pond system Liquids Pond system Solids (sludge) (Anaerobic, Facultative, Maturation) Solids (sludge) (Anaerobic, Facultative, Maturation) Reusable co-product Reusable co-product Model system: FS-3 Model system: FS-4

Manual Screen Holding/mixing tank Vacuum tanker Vacuum tanker Manual Screen Holding/ Mechanized mixing tank dewatering Compost Co-composting LEGEND Sludge Drying Bed LEGEND (unplanted with roof) (Windrow) Fecal sludge Fecal sludge Discharge Liquids Discharge Liquids Solids (sludge) Aerated Pond Maturation Pond Solids (sludge) Chlorination Reusable co-product (incl. settling pond) Reusable co-product (Packaged) Model system: G-OP, or Large Omni-Processor with Gasifier Treated liquid Receiving & Dewatering Liquid Supernatant Fecal Screening (Screw Press) Treatment Process (reuse/discharge) Vacuum tanker sludge Clean Dewatered Sludge Water Solids LEGEND drier Power Fecal sludge Boiler + Electricity Separation Gasifier & Process Turbine + Liquids of MSW Boiler Dried Air emissions Solids (sludge) MSW Heat Ash; Fuel source solids process Air emissions Additional input Landfill Site (start-up & Supplement) Heat OP Technology

Model system: P-OP, or -Based Small Omni-Processor

FSTP Technology Treated liquid effluent Fecal Vacuum tanker sludge Pasteurization treatment LEGEND Grit removal & Mechanized Heat Heat Fecal sludge screening Storage dewatering /Ash (reuse/landfill) Liquids Dewatered sludge Solids (sludge) Thermal drier Pyrolysis Additional input Heat Biomass Start-up fuel Model system: SCWO-OP, or Supercritical Water Oxidation Omni-Processor* Electricity Polymer mixing Low-grade thermal heat water Wash-water SCWO Dewatered Distilled & hot water Vacuum tanker sludge Storage Salts/minerals OP Technology LEGEND Fecal sludge Fecal Mechanical Liquids sludge Mechanical grit Mixing Tank dewatering High-quality Solids (sludge) removal (Polymer) effluent discharge Heat / energy Returned sludge Activated Sludge Additional system input (Packaged)

* Note that SCWO-OP is a future technology that is still under development.