How to Size a Containerized MBR STP in Miami, FL (2026 Guide)

What 'Sizing' a Containerized MBR STP Actually Means in Miami

Sizing a containerized MBR (membrane bioreactor) sewage treatment plant in Miami is a four-variable calculation: (1) count the design occupancy of the residential block or camp; (2) multiply by 50 gpd (US gallons per day) per capita — the per-capita basis published for containerized MBRs (Pure Aqua, MBR-C product page) — to get average daily flow; (3) apply a peaking factor for Florida morning/evening simultaneity and tourist peaks; (4) convert the result into m³/day using 1 m³ = 264.2 US gallons and match it to a 20' or 40' high-cube ISO container, since one 40-foot ISO frame can host more than 1,200 m³/day (MENA-Water, MBR product page). Miami's warm sewage sits inside the typical 68–86°F (20–30°C) MBR operating window (Pure Aqua, MBR-C product page), so no special heating is required.

"Containerized" in this context refers strictly to the ISO frame (20' or 40' high-cube), not to the underlying process. The treatment chain is a conventional activated-sludge basin followed by a submerged ultrafiltration (UF) membrane stage, with a 1.5 mm drum screen on the feed (Pure Aqua, MBR-C product page) and a hollow-fiber UF membrane with a nominal 0.04 µm pore size that achieves 99.9999% virus and bacteria reduction (MENA-Water, MBR product page). Treating "containerized" as a sizing input — rather than as a sales label — is what separates a defensible Florida submittal from a marketing brochure. Miami-specificity enters through two of the four variables: feed temperature (which is already inside the design window) and peaking (which is amplified by tourism seasonality and short-stay resort occupancy).

Step 1 — Build the Occupancy Profile for the Miami Project

Every downstream number — flow, container count, electrical load, blower sizing — is anchored to the design population, so the first deliverable is a written occupancy assumption, not a flow rate. Three Miami project types each need a different way of counting people.

For residential: use the actual bedroom count multiplied by the Florida Building Code occupancy factor for the unit type. Do not size on the marketing brochure's "200-unit community" claim without checking how the developer is counting studios versus three-bedrooms, because the bedroom mix drives both the population and the peak-morning simultaneity that hits a small MBR skid.

For a workers' camp or construction camp: take the maximum shift headcount stated in the camp operator's contract, add catering and cleaning staff, and confirm the total against the operator's mobilization plan. A 400-person camp on a Doral site is rarely 400 persons at the biological stage; the realistic number sits closer to the headcount plus 10–15% for support staff, and any downstream MBR sizing that misses that adjustment gets revisited in commissioning.

For a resort or seasonal event site: size to peak occupancy, not annual average, because Miami's tourism calendar concentrates load in the winter and spring dry season when occupancy is at its highest and irrigation reuse demand is also at its highest. A resort that averages 60% occupancy but peaks at 100% in February will undersize its MBR if the average is used.

Step 2 — Convert Occupancy to Design Flow with the 50 gpd per Capita Basis

Once the design population is fixed, the second step is to convert it into an average daily flow using the published 50 gpd per capita basis (Pure Aqua, MBR-C product page). For a 200-unit residential community at, say, 2.4 persons per unit (480 design population), the average daily flow is 480 × 50 = 24,000 gpd. For a 1,000-person resort or event camp it is 1,000 × 50 = 50,000 gpd. This is a published equipment-sizing basis, not a Florida regulatory value; treat it as a starting number and document the assumption in the design basis memorandum.

Convert gpd into m³/day using the IDA Handbook 2020–2021 convention: 1 m³ = 264.2 US gallons (IDA Water Security Handbook 2020–2021, unit conversion table). The working short-cut is that 1,000 gpd ≈ 3.785 m³/day, the same 3,785 m³/d per MGD anchor that runs through the U.S. water industry. So 24,000 gpd becomes 24 × 3.785 = 90.8 m³/day, and 50,000 gpd becomes 50 × 3.785 = 189.3 m³/day. These are the average daily flow figures that go onto the P&ID before any peaking is applied.

Sanity-check the result against typical Miami residential indoor water use. If the calculated flow is wildly above or below utility billing data for a comparable project, the wrong number to revisit is the occupancy figure, not the per-capita basis. Record the average daily flow in m³/day before peaking, because peaking is a multiplier on a defensible average, not a substitute for a wrong population count.

Step 3 — Apply a Miami Peaking Factor and Check the Temperature Window

The third step multiplies the average day number by a peaking factor that reflects how Miami actually uses water. A defensible starting band is roughly 2–3× average daily flow for peak day, and up to ~4–5× for peak hour, with the higher end of the range reserved for tourist peaks and short-stay camps where morning and evening simultaneity compresses into a narrow window. For the 480-person residential example at 90.8 m³/day, a 2.5× peak day yields about 227 m³/day, well inside the >1,200 m³/day capacity of a single 40-foot ISO container (MENA-Water, MBR product page). For the 1,000-person resort at 189.3 m³/day, a 3× peak day yields about 568 m³/day — still inside one 40-foot envelope, but with much less headroom, which is the cue to plan a second parallel train at the bid stage rather than to oversize a single skid.

Confirm that Miami ambient and sewage temperature sits inside the published MBR operating window of 68–86°F (20–30°C) with a design point of 68°F (20°C) (Pure Aqua, MBR-C product page). Cold-weather insulation and heating are not in the scope; if a Miami project ever does fall below the window, the cause is almost always an oversized equalization tank or a chilled return line, not the climate. Miami's year-round warmth is a sizing advantage, not a problem to design around.

Use the 460V / 3-phase / 60 Hz electrical specification (Pure Aqua, MBR-C product page) to size the site service from day one. This is a hard interface, not an option. Specifying anything else (230V three-phase, 50 Hz, single-phase residential service) is the single most common reason a factory-built containerized MBR has to be rewired on a Florida site, and the cost of that rework belongs in the risk register at the bid stage, not in the change-order log after delivery.

Population, Flow and Container Count — Miami Reference Table

The table below maps three Miami-relevant project types through the sizing chain described in Steps 1–3, using the 50 gpd per capita basis (Pure Aqua, MBR-C product page), the 2.5× peak day multiplier, and the >1,200 m³/day in a single 40-foot ISO frame (MENA-Water, MBR product page). It is a planning instrument, not a vendor quotation. For an alternative container architecture — a smaller packaged plant sited next to a borehole for a remote camp — see the siting guide for package treatment plants.

Across all three rows, pre-treatment is a 1.5 mm drum screen and the membrane stage is a 0.04 µm hollow-fiber UF module (Pure Aqua, MBR-C product page) — the same process chain a vendor will quote against, so the table and the bid sheet speak the same language. The HydropureWater integrated MBR system matches this process chain and the 460V/3Ph/60Hz site tie-in used throughout the table.

Choosing 20' vs 40' HC, U-Version vs I-Version for a Miami Site

The hydraulic answer from Step 3 turns into a physical skid only after two more decisions: container size, and the U-Version / I-Version split described in the MENA-Water product literature.

Use 20' high-cube containers for small residential clusters and satellite camps where average day flow is well under 200 m³/day. A 50-person camp at 9.5 m³/day (table above) is a clean 20' HC fit, and a single 20' unit can be trucked into a tight Miami-Dade site without a wide-load permit. Reserve 40' HC units for the main plant on any project above roughly 100 m³/day of average flow, because the 40' frame is what hosts the >1,200 m³/day single-skid capacity (MENA-Water, MBR product page) and the larger equalization volume a peaky Miami load actually needs.

Specify the I-Version for camps that may be relocated. The I-Version is fully integrated and mobile, designed by MENA-Water for "mobile applications or if the plants need to be shifted to new locations" (MENA-Water, MBR product page) — exactly the use case for a Doral construction camp that hands back to a developer after two years. Specify the U-Version when above-grade footprint is the binding constraint, as on a finished residential community where landscaping must remain intact: in the U-Version, "aeration and buffering takes place inside underground water tanks" (MENA-Water, MBR product page), which shrinks the visible package to the membrane and control container.

Insist on a factory acceptance test and plug & play wiring per the MENA-Water model, so the 460V/3Ph/60Hz site tie-in (Pure Aqua, MBR-C product page) is the only electrical work on the Miami site. The HydropureWater integrated MBR system and the DF series PVDF flat sheet MBR module are both built around that plug & play interface, and either is a defensible shortlist entry against the table above. For an international comparison of how the same sizing workflow plays out in a colder, smaller-flow market, see the containerized MBR sizing guide for Birmingham; for a higher-temperature, higher-flow Middle Eastern case, see the containerized MBR sizing guide for Jeddah.

U.S. Unit Conversions Every Florida Engineer Should Keep on the Drawing

The same flow number will be quoted in gpd on a utility submittal, in m³/day on a vendor P&ID, and in MGD on a reuse permit. Convert once, early, using the IDA Handbook 2020–2021 convention (IDA Water Security Handbook 2020–2021, unit conversion table), and put the conversion table on the cover sheet of the calculation package so the reviewer does not have to re-derive it.

Flag that MBR plant output in Miami is normally discussed in m³/day on the process side, but the utility tie-in, sewer discharge permit, and water reuse submittal are all in U.S. customary units. Run all design calculations on the basis of 365¼ days per calendar year (IDA Water Security Handbook 2020–2021), consistent with the convention used in the table above, so annual reuse yield figures line up with utility billing cycles and with any reuse offset the developer is claiming in the pro forma.

Frequently Asked Questions

How do I turn a "200-unit residential" project description into a defensible design population for a containerized MBR?

Start from the bedroom count in the developer's unit mix, apply the Florida Building Code occupancy factor for each unit type, and write the resulting number into the design basis memorandum before any flow is calculated. The published 50 gpd per capita basis (Pure Aqua, MBR-C product page) multiplies onto that fixed population — it does not replace it. If the developer cannot produce a unit mix, request one in writing; do not back-derive population from a marketing brochure's "200 units."

How many 20' or 40' high-cube containers do I need for a Miami camp or residential project?

Use the published >1,200 m³/day capacity of a single 40-foot ISO frame (MENA-Water, MBR product page) as the upper single-skid anchor. For the 480-person residential example in the reference table, one 40' HC unit is sufficient at average day (90.8 m³/day) and at peak day (227 m³/day). For the 1,000-person resort at 473 m³/day peak, one 40' HC carries the load with limited headroom — a second 40' HC should be planned at the bid stage rather than as a change order. Request from each shortlisted vendor a written confirmation of the 1,200 m³/day single-frame figure and a peak-day turn-down curve.

What effluent quality and pathogen reduction should I specify when I shortlist suppliers?

Specify the 0.04 µm hollow-fiber UF membrane (Pure Aqua, MBR-C product page) with a virus and bacteria reduction of 99.9999% (MENA-Water, MBR product page) as the minimum membrane performance line, and require a 1.5 mm drum screen on the feed (Pure Aqua, MBR-C product page) to protect membrane life. Ask each vendor for a log-reduction statement, a membrane material data sheet (PVDF TIPS for the Pure Aqua SMM line), and a chemical-cleaning interval — typically one or two maintenance clearings per year (MENA-Water, MBR product page) — so the O&M cost is on the bid sheet from day one.

Which compliance and siting documents should I request before I commit to a supplier for a Florida project?

Ask each shortlisted vendor for a written statement that the unit is built to the 460V/3Ph/60Hz site tie-in (Pure Aqua, MBR-C product page), that it is rated for the 68–86°F (20–30°C) operating window with a 68°F (20°C) design point (Pure Aqua, MBR-C product page), and that the proposed architecture is the I-Version (mobile) or U-Version (underground buffer/aeration) per the MENA-Water product description (MENA-Water, MBR product page). For cost, budget, and lead-time inputs — and for FDEP / Chapter 62-6 reuse compliance — request those directly from the vendor and from FDEP; those figures are not in the published product literature and should not be estimated from typical ranges.