Plan-It STOAT Software
Plan-It STOAT is a wastewater treatment plant design tool. The program comprises Steady-state process modelling (either estimating the size of process units for a required effluent quality, or the effluent quality for the given size); Steady-state hydraulic analysis; Costing; and Layout The costing uses a mixture of US and UK data and produces costs appropriate for 1998. The costs can be adjusted by applying appropriate inflation indices to update to them to the required year. The hydraulic analysis models were provided by CDM and encompass most hydraulic elements used at sewage treatment works. WRc has used Plan-It STOAT for clients to first replicate earlier Walling Software CHAT models, and then apply the Plan-It STOAT model to new hydraulic conditions. The hydraulic model has also been applied to new-build systems.
The most extensively used part of Plan-It STOAT has been the process models. The models cover most major process used at sewage treatment plants, and includes specific design models as well as more general models such as the IWA activated sludge models ASM1, ASM2d and ASM3. There is support for sensitivity analysis and Monte-Carlo analysis to assist in understanding the impact of poorly-known parameters on the the overall performance. WRc has used the process modelling aspect at many UK sewage sites, and also in the Middle East; Plan-It STOAT has also been used by others in the USA, Europe and Asia.
The output from Plan-It STOAT includes:
- Estimates of unit process facility volumes and land area requirements;
- A hydraulic profile;
- A mass balance;
- Site energy requirements;
- Site chemical requirements; and
- Estimated capital and operating costs.