[{"key":"temperate-inland","name":"Temperate inland town","description":"A conventional medium-strength municipal catchment on a combined sewer, sized on the winter design temperature.","exercises":"The base case. Nothing unusual binds; useful as a reference run.","cod_tkn_ratio":11.428571428571429,"caveat":"Composed, not measured. No scenario describes a real works. The ratios between COD, TKN and alkalinity are internally consistent so a seeded study behaves sensibly, but consistency is not accuracy -- a real catchment is characterised from sampling, and the design temperature in particular is a statistical minimum rather than a typical value","fields":{"flow_m3_d":20000.0,"influent_cod_mg_l":480.0,"influent_tkn_mg_l":42.0,"influent_alkalinity_mol_m3":6.0,"temperature_c":12.0,"cost_index":112.0,"peak_wet_factor":3.0,"available_head_m":4.5}},{"key":"coastal-seasonal","name":"Coastal resort, seasonal load","description":"Dilute wastewater from a catchment with significant groundwater infiltration, on a flat site with very little available fall.","exercises":"Head. A 3.2 m budget against a 3.5x wet-weather peak puts the hydraulic profile in the binding position rather than the biology.","cod_tkn_ratio":11.428571428571429,"caveat":"Composed, not measured. No scenario describes a real works. The ratios between COD, TKN and alkalinity are internally consistent so a seeded study behaves sensibly, but consistency is not accuracy -- a real catchment is characterised from sampling, and the design temperature in particular is a statistical minimum rather than a typical value","fields":{"flow_m3_d":35000.0,"influent_cod_mg_l":320.0,"influent_tkn_mg_l":28.0,"influent_alkalinity_mol_m3":4.5,"temperature_c":16.0,"cost_index":128.0,"peak_wet_factor":3.5,"available_head_m":3.2}},{"key":"dense-urban","name":"Dense urban catchment","description":"Strong wastewater at the top of the envelope, on separate sewers so the wet-weather peak is modest.","exercises":"Scale and footprint. The largest flow in the set against the default site, so the packer has to work for its answer.","cod_tkn_ratio":10.483870967741936,"caveat":"Composed, not measured. No scenario describes a real works. The ratios between COD, TKN and alkalinity are internally consistent so a seeded study behaves sensibly, but consistency is not accuracy -- a real catchment is characterised from sampling, and the design temperature in particular is a statistical minimum rather than a typical value","fields":{"flow_m3_d":50000.0,"influent_cod_mg_l":650.0,"influent_tkn_mg_l":62.0,"influent_alkalinity_mol_m3":7.5,"temperature_c":18.0,"cost_index":135.0,"peak_wet_factor":2.5,"available_head_m":6.0}},{"key":"cold-climate","name":"Cold-climate northern works","description":"A works whose winter design temperature sits close to the limit for reliable nitrification, in a high-cost construction market.","exercises":"Nitrification. At 8 C the autotrophs grow slowly enough that sludge age drives the reactor volume, so compliance binds first.","cod_tkn_ratio":11.458333333333334,"caveat":"Composed, not measured. No scenario describes a real works. The ratios between COD, TKN and alkalinity are internally consistent so a seeded study behaves sensibly, but consistency is not accuracy -- a real catchment is characterised from sampling, and the design temperature in particular is a statistical minimum rather than a typical value","fields":{"flow_m3_d":25000.0,"influent_cod_mg_l":550.0,"influent_tkn_mg_l":48.0,"influent_alkalinity_mol_m3":6.5,"temperature_c":8.0,"cost_index":145.0,"peak_wet_factor":2.8,"available_head_m":5.0}},{"key":"arid-reuse","name":"Arid region, water reuse","description":"Concentrated wastewater from a low per-capita-consumption catchment, warm year-round, with a low wet-weather peak.","exercises":"Load rather than flow. High strength at moderate flow makes aeration demand and sludge production dominate operating cost.","cod_tkn_ratio":10.588235294117647,"caveat":"Composed, not measured. No scenario describes a real works. The ratios between COD, TKN and alkalinity are internally consistent so a seeded study behaves sensibly, but consistency is not accuracy -- a real catchment is characterised from sampling, and the design temperature in particular is a statistical minimum rather than a typical value","fields":{"flow_m3_d":30000.0,"influent_cod_mg_l":720.0,"influent_tkn_mg_l":68.0,"influent_alkalinity_mol_m3":8.0,"temperature_c":24.0,"cost_index":118.0,"peak_wet_factor":2.2,"available_head_m":4.0}}]