Why Brasília Hotels Need a Packaged MBR, Not a Conventional STP
Brasília sits at roughly 1,172 m above sea level, where atmospheric pressure drops to about 88 kPa — about 88% of sea level — and that single number derates fine-bubble diffuser efficiency from ~6 kg O₂/kWh at sea level to ~5 kg O₂/kWh on the Planalto Central. A packaged membrane bioreactor (MBR) absorbs that derating inside an oversized blower and a submerged membrane zone, while a conventional activated-sludge or SBR plant eats the same derating as lost aeration tank volume. The tropical savanna climate (Aw per Köppen) layers a second problem: dry-season lows of 15–18 °C slow nitrification kinetics by 30–50% below the 20 °C threshold, and the wet season delivers hydraulic peaks of 1.5–2.0× the dry-season average. On top of that, Brasília's DF potable tariff structure and recurring scarcity in the Lago Paranoá basin make on-site reuse for toilet flushing, irrigation, and cooling-tower make-up economically rational — a 200-room hotel that consumes ~100 m³/d of potable water can offset 30–40% with MBR reuse, and the MBR delivers 90–95% recovery in a single step (per Imemflo's hotel solution page). MBBR, SBR, and ASP need a downstream tertiary stage to hit ADASA coliform and TSS reuse limits; a submerged MBR is the only packaged option that hits reuse-quality effluent and a 30–50 m² footprint in one tank. The companion Brussels hotel MBR sizing guide covers the same workflow at sea level — the differences here are altitude, climate, and CONAMA 430/2011.
Step 1 — Estimate Design Flow and Pollutant Load
Hotel design flow in Brasília starts at 0.30–0.45 m³ per guest-night for mid- to high-end properties, plus 0.05–0.10 m³/employee/day for staff. Apply a peak factor of 1.5–2.0× the average daily flow to size equalization and the membrane train's hydraulic capacity. The raw wastewater envelope a CAESB reviewer will expect to see is BOD 250–450 mg/L, COD 600–1,200 mg/L, TSS 200–400 mg/L, FOG 50–150 mg/L from kitchen flow, plus surfactants and TDS from the laundry stream (per the Imemflo hotel wastewater characterization). Brasília hotels commonly split flows: a separate greywater/laundry train handles the 15–25% of total flow that comes from the lavanderia, which carries high TDS, surfactants, and lint; route it either to a dedicated MBR or to a physico-chemical DAF before rejoining the main biological train.
Working example — a 200-key business hotel in Brasília with 80% occupancy, 60 staff, a restaurant, and an in-house laundry: average flow ≈ 200 × 0.40 × 0.8 + 60 × 0.08 = 68.8 m³/d, peaking near 138 m³/d. Round to a 150 m³/d packaged MBR for nominal duty, or a 200 m³/d unit if the operator wants headroom for a wet-season surge or a future 100-key expansion. Use the table below to anchor the load numbers a reviewer will check.
| Parameter | Design value | Source / basis |
|---|---|---|
| Average flow, 200-key hotel | ~69 m³/d (≈0.34 m³/key-night) | 0.30–0.45 m³/guest-night + staff allowance |
| Peak flow | 1.5–2.0× average ≈ 104–138 m³/d | Hydraulic peak factor |
| Raw BOD₅ | 250–450 mg/L | Imemflo hotel characterization, 2026 |
| Raw COD | 600–1,200 mg/L | Imemflo hotel characterization, 2026 |
| Raw TSS | 200–400 mg/L | Imemflo hotel characterization, 2026 |
| FOG (kitchen) | 50–150 mg/L | Imemflo hotel characterization, 2026 |
| Laundry share of total flow | 15–25% | Hotel convention, Imemflo S2 |
| Sizing recommendation | 150 m³/d (nominal) or 200 m³/d (with headroom) | Round up from 69 m³/d average |
Step 2 — Apply the Brasília Altitude Correction to Aeration Design
At 1,172 m altitude, atmospheric pressure is ~88 kPa and the SOTR-to-AOTR conversion factor is ~0.88 — meaning a blower that delivers "X kg O₂/h" at sea level delivers only ~0.88X at Brasília. Fine-bubble diffuser SOTE falls from ~6 kg O₂/kWh to ~5 kg O₂/kWh (per Gillot & Héduit 2000 oxygen-transfer correlations re-evaluated for altitude, HydropureWater field data, 2026), and the engineer must oversize the blower by 12–15% over a sea-level selection. Inside the MBR tank, hold MLSS at 8,000–12,000 mg/L to maintain an F/M ratio of 0.05–0.15 kg BOD/kg MLVSS·d — that range protects membrane permeability and gives the nitrifiers enough solids residence time at lower temperatures. Design for 18–25 °C: below 20 °C, nitrification rate drops and HRT must rise from 6–8 h to 8–10 h, increasing tank volume by roughly 20% (per Metcalf & Eddy temperature correction, applied to Brasília's dry-season range).
| Altitude parameter | Sea level (0 m) | Brasília (1,172 m) | Derating / correction |
|---|---|---|---|
| Atmospheric pressure | 101.3 kPa | ~88 kPa | ×0.87 (88% of sea level) |
| SOTR → AOTR factor | 1.00 | ~0.88 | Derate blower nameplate |
| Fine-bubble SOTE | ~6 kg O₂/kWh | ~5 kg O₂/kWh | +12–15% blower power |
| MLSS target (MBR) | 8,000–12,000 mg/L | 8,000–12,000 mg/L | F/M 0.05–0.15 kg BOD/kg MLVSS·d |
| HRT at T < 20 °C | 6–8 h | 8–10 h | +20% tank volume in dry season |
Step 3 — Specify the Membrane Module and Flux
Specify a submerged PVDF ultrafiltration membrane — hollow fiber or flat sheet — with pore size 0.03–0.1 μm. The named global suppliers in the hotel MBR segment are Suez, Dow, DuPont, and Mitsubishi for hollow fiber, and Toray for flat sheet (per the Imemflo hotel page). Run the membrane at 15–25 L/m²·h design flux at 8,000–12,000 mg/L MLSS; lower flux (12–18 L/m²·h) extends membrane life and reduces chemical-cleaning frequency, which matters in a hotel where the operator has no in-house membrane specialist. Operate on a 9–10 minute suction / 1–2 minute relaxation cycle with periodic backwash, and use a factory-built packaged unit that integrates the membrane zone, aeration scour, and cleaning CIP into a single skid (per the Smith & Loveless TITAN MEM-BOX™ concept, 2026). Out of the MBR, expect TSS removal above 99% and turbidity below 1 NTU — that quality is what lets a downstream UV or ClO₂ polishing step hit the ADASA coliform limit for non-potable reuse without heroic dose rates. The procurement line should read: "Submerged PVDF UF, 0.03–0.1 μm pore, packaged MBR with integrated aeration scour and CIP, design flux 15–25 L/m²·h, supplied as factory-tested skid" — anchored to the integrated MBR membrane bioreactor system and, if a flat-sheet variant is preferred, the PVDF flat-sheet membrane module. For an altitude-similar context where the same PVDF UF selection logic applies, see the La Paz altitude derating guide.
| Spec line | Value | Notes |
|---|---|---|
| Membrane type | Submerged PVDF UF (hollow fiber or flat sheet) | Suez / Dow / DuPont / Mitsubishi (HF), Toray (FS) |
| Pore size | 0.03–0.1 μm | Ultrafiltration range |
| Design flux | 15–25 L/m²·h | MLSS 8,000–12,000 mg/L |
| Operating cycle | 9–10 min suction / 1–2 min relaxation + backwash | Standard hotel duty |
| Effluent TSS | < 5 mg/L (typ. < 1 NTU) | >99% TSS removal |
| Effluent turbidity | < 1 NTU | Sufficient for UV/ClO₂ polishing |
Step 4 — Match the Process to CONAMA 430/2011 and ADASA Reuse Rules
Brazilian national discharge is governed by CONAMA Resolution 430/2011, which sets BOD ≤ 120 mg/L (5-day) for release to water bodies. Brasília hotels discharging to the CAESB sewer face stricter influent limits (typically BOD ≤ 300 mg/L, COD ≤ 600 mg/L, TSS ≤ 200 mg/L) plus ADASA reuse criteria for any on-site non-potable reuse. The ADASA reuse envelope for hotel-scale applications is thermotolerant coliforms ≤ 1,000 NMP/100 mL and TSS ≤ 5 mg/L; the MBR alone hits TSS < 1 NTU and removes > 99.9% of bacteria, so a downstream polishing block — typically a UV sterilizer or a chlorine dioxide generator — closes the coliform gap without a tertiary clarifier. If the hotel discharges to the Lago Paranoá basin, the regulator will require ammonia control (N-NH₃ ≤ 20 mg/L); specify a pre-anoxic zone in the packaged MBR to achieve partial nitrification-denitrification and drop TKN by 60–80% before the aerobic MBR stage. Always confirm the current ADASA/CAESB envelope at spec time — Brasília regulators revise reuse triggers periodically, and the 2026 ADASA water-reuse ordinance is the controlling document for any permit.
Step 5 — Choose the Packaged Format and Footprint
Two packaged formats are relevant for Brasília hotels. A buried WSZ underground package plant suits space-constrained or landscaping-sensitive sites — rooftop pools, garden courtyards, podium-level mechanical rooms — but limits access for membrane replacement and ties tank volume to crane and traffic-load constraints. An above-grade skid/containerized MBR (Smith & Loveless MEM-BOX / Imemflo integrated units) gives full O&M access, faster installation, and easy membrane swap, which is what a hotel with mechanical-room space typically prefers. For a 150–250 m³/d hotel MBR, expect a 30–50 m² footprint versus 100–150 m² for an equivalent SBR (per Imemflo S3, "compact plant, less space, less construction work"). The full treatment train a Brasília hotel should plan is: grit chamber → fine screen (≤ 3 mm) — a rotary mechanical bar screen handles this — grease interceptor → equalization → packaged MBR → sludge holding → dewatering via a plate-and-frame filter press → UV or ClO₂ disinfection → reuse tank. The CASS process is sometimes proposed as a cheaper alternative; the trade-offs against submerged MBR are detailed in the CASS process working principle guide.
| Train stage | Equipment | Design function |
|---|---|---|
| 1. Preliminary | Grit chamber + rotary bar screen (≤ 3 mm) | Solids removal, protects downstream |
| 2. FOG | Grease interceptor | Kitchen flow protection |
| 3. Equalization | EQ tank with mixer | 1.5–2.0× peak attenuation |
| 4. Biological + membrane | Packaged MBR skid | BOD/COD removal + UF separation |
| 5. Sludge | Holding tank + plate-and-frame filter press | Dewatering to ~22% DS cake |
| 6. Polishing | UV or ClO₂ | Coliform < 1,000 NMP/100 mL |
| 7. Reuse | Reuse tank + distribution | Toilet / irrigation / cooling tower |
Step 6 — Procurement, CAPEX/OPEX, and Acceptance Test
CAPEX benchmark for a packaged MBR in the 150–250 m³/d range in Brazil is roughly USD 250,000–450,000 installed (tankage, blowers, membranes, controls, disinfection) — call it a 15–25% premium over an equivalent SBR. OPEX drivers scale with the membrane: PVDF replacement every 5–8 years, monthly chemical cleaning (NaOCl + citric acid), quarterly sludge hauling, and 0.8–1.5 kWh/m³ for the packaged MBR with coarse-bubble membrane scour (HydropureWater field data, 2026). The reuse economics do the heavy lifting on payback: a 200-room hotel at ~100 m³/d potable demand can offset 30–40% with reuse, and at Brasília's tariff structure that recovers the MBR CAPEX premium versus SBR in 3–5 years. Lock the supplier down with a factory acceptance test (FAT) and site acceptance test (SAT) protocol that includes a 72-hour performance run at design flow, BOD/TSS/NH₃-N/thermotolerant-coliform results against the spec table, a membrane integrity test (pressure-decay, ≤ 0.1 kPa/min for 0.1 μm pores), and a 12-month membrane warranty with a defined prorated replacement schedule. Use the table below to make sure the procurement line items match the spec.
| Cost line | Range (USD, 150–250 m³/d) | Notes |
|---|---|---|
| CAPEX — packaged MBR installed | 250,000–450,000 | Tankage, blowers, membranes, controls, UV/ClO₂ |
| CAPEX premium vs SBR | +15–25% | Membrane zone, higher blower, CIP |
| OPEX — energy | 0.8–1.5 kWh/m³ | Coarse-bubble scour included |
| OPEX — membrane replacement | Every 5–8 years (PVDF) | Include in life-cycle cost |
| OPEX — chemical cleaning | Monthly (NaOCl + citric) | Schedule per flux decay |
| Reuse offset | 30–40% of ~100 m³/d potable demand | 3–5 year payback on MBR premium |
| Acceptance test gate | 72-h run + integrity test | BOD/TSS/NH₃-N/coliform vs spec |
Frequently Asked Questions
What design flow should I use to size a packaged MBR for a Brasília hotel?
For a mid- to high-end Brasília hotel, size at 0.30–0.45 m³ per guest-night plus 0.05–0.10 m³/employee/day, and apply a 1.5–2.0× peak factor for equalization and membrane-train hydraulics. A 200-key, 80%-occupied business hotel with 60 staff and a laundry works out to ~69 m³/d average, peaking near 138 m³/d — round to a 150 m³/d packaged MBR or a 200 m³/d unit for headroom.
How does Brasília's 1,172 m altitude change aeration sizing for an MBR?
Atmospheric pressure at Brasília is ~88 kPa, so the SOTR-to-AOTR factor is ~0.88 and fine-bubble diffuser SOTE drops from ~6 kg O₂/kWh at sea level to ~5 kg O₂/kWh (HydropureWater field data, 2026). Oversize the blower by 12–15% over a sea-level selection, hold MLSS at 8,000–12,000 mg/L, and raise HRT from 6–8 h to 8–10 h when basin temperature drops below 20 °C in the dry season.
Which membrane type and flux should I specify for a hotel MBR in Brasília?
Specify submerged PVDF ultrafiltration — hollow fiber or flat sheet — at 0.03–0.1 μm pore size, with design flux 15–25 L/m²·h at 8,000–12,000 mg/L MLSS and a 9–10 min suction / 1–2 min relaxation cycle. Named hotel-segment suppliers are Suez, Dow, DuPont, and Mitsubishi for hollow fiber, and Toray for flat sheet (per Imemflo, 2026); a packaged skid with integrated CIP is preferred for sites without in-house O&M staff.
What effluent quality does a packaged MBR need to meet CONAMA 430/2011 and ADASA reuse rules in Brasília?
CONAMA 430/2011 sets BOD ≤ 120 mg/L for discharge, but ADASA reuse for non-potable applications is tighter: thermotolerant coliforms ≤ 1,000 NMP/100 mL and TSS ≤ 5 mg/L. An MBR alone hits TSS < 1 NTU and > 99.9% bacteria removal; a polishing UV or ClO₂ block closes the coliform gap, and a pre-anoxic zone drops N-NH₃ below 20 mg/L for Lago Paranoá basin discharges.
How long is the payback on a packaged MBR for a Brasília hotel with on-site reuse?
At a CAPEX premium of 15–25% over an SBR (USD 250,000–450,000 installed for 150–250 m³/d) and 0.8–1.5 kWh/m³ OPEX, the reuse economics carry the payback: a 200-room hotel at ~100 m³/d potable demand can offset 30–40% with MBR reuse, recovering the MBR CAPEX premium in 3–5 years at Brasília's potable tariff structure (HydropureWater field data, 2026).
