What "sizing" a containerized MBR STP actually means in Seoul
Sizing a containerized MBR sewage treatment plant is a three-output engineering problem: the design flow in m³/day, the biological tank volume set by BOD/COD loading, and the submerged PVDF membrane area set by flux. Getting any one of these wrong skews the others, which is why a defensible Seoul sizing must be walked end to end before a container count is requested. Containerized MBR packages in the HydropureWater catalog are offered in the 10–2,000 m³/day envelope, which matches the realistic band for Seoul residential blocks and worker camps served by a containerized MBR system.
Three of the inputs are not in the supplier's data sheet: the binding effluent parameter list, the Han River basin winter mixed-liquor temperature, and the available site footprint. These are the items that decide the final container count, and they should be confirmed with a Korean EPC or the local authority before any sizing is locked. A method that works in Cebu or Riyadh can over- or under-size a Seoul plant by a full container if those three constraints are not addressed first.
Step 1 — Convert the design population into a design flow
Design flow is calculated by multiplying the population by the per-capita wastewater contribution and applying a peaking factor to account for morning and evening surges. Per-capita values for Korean residential and camp occupancy are not specified in the supplied research and should be requested from a Korean EPC or the relevant authority rather than assumed from a generic international range, because Seoul apartment blocks and construction-camp occupancy patterns differ from the assumptions in foreign sizing guides.
The unit m³/day is the standard convention used in plant inventories such as the IDA Water Security Handbook 2020–2021, which reports reuse and desalination plant capacity on a per-day cubic-metre basis (Global Water Intelligence / IDA, 2020–2021). Staying in m³/day keeps the design flow comparable to vendor ratings and to any reference projects the EPC supplies. For camp projects, add a transient surge margin because occupancy fluctuates with shift rotations and weekend turnarounds; the specific surge value is also not provided in the supplied research and must be confirmed with the EPC against the project's worst-case occupancy.
Step 2 — Set biological load and tank volume from BOD and COD
Biological tank volume is driven by the daily organic load in kg BOD/day and kg COD/day. The load is the design population multiplied by a per-capita BOD and COD contribution, and the supplied research does not contain Korean per-capita BOD figures, so these must be sourced from a Korean EPC rather than assumed from a generic textbook value. Once the daily load is fixed, the tank volume is set by the target mixed-liquor suspended solids (MLSS) concentration and the food-to-microorganism (F/M) ratio; these are also not specified in the supplied research and should be confirmed with the equipment vendor and any Korean design reference the EPC holds.
Seoul winter mixed-liquor temperature is the variable that most often breaks a foreign design: colder mixed liquor reduces the nitrification rate and pushes the required tank volume up. The winter temperature profile for the Han River basin is not provided in the supplied research and should be requested from a Korean EPC along with the site elevation, because the same MBR module behaves differently at 8 °C mixed liquor than at 18 °C. Treat the lowest expected temperature, not the annual average, as the design point for the biological stage.
Step 3 — Match membrane area to flow using module output
Membrane area and module count provide the buyer's first tangible sizing answer. Containerized MBR systems in the HydropureWater catalog are framed as 10–2,000 m³/day packages, so the design flow from Step 1 should fall inside that envelope before module selection begins (HydropureWater MBR product page). DF series PVDF flat-sheet modules are available in 80–225 m² sizes producing 32–135 m³/day per module, and dividing the design flow by the chosen module output gives the module count and then the container count (HydropureWater DF series product page).
Containerized plants are most often overloaded at peak hour, not at average day, so the engineer should confirm peak instantaneous flux rather than relying on the average flux implied by the per-module m³/day rating. The membrane area is sized to pass the peak hour with a flux that the module's manufacturer data supports; otherwise, a plant that meets the daily average will still spill during the morning peak. A sizing method that ignores peak flux is the most common reason for a containerized MBR to fail its first wet-season or shift-change test.
| Parameter | Value or range | Source |
|---|---|---|
| Containerized MBR package envelope | 10–2,000 m³/day | HydropureWater MBR product page |
| DF series module membrane area | 80–225 m² | HydropureWater DF series product page |
| DF series per-module output | 32–135 m³/day | HydropureWater DF series product page |
| Footprint vs. conventional activated sludge | about 60% smaller | HydropureWater MBR product page |
| Design unit convention | m³/day | IDA Water Security Handbook 2020–2021 |
Step 4 — Apply Seoul-specific site and compliance constraints
Korean effluent limits for residential and camp discharge are not specified in the supplied research, so the engineer should request the exact parameter list and limits from the local authority or a Korean EPC before design is finalised. Treating the limits as a generic international standard is a frequent source of non-compliance, because Korean nutrient limits for small-community discharge are often tighter than the values quoted in foreign sizing guides. The list of parameters to confirm includes BOD, COD, total nitrogen, total phosphorus, and suspended solids, plus any site-specific requirements the Seoul site triggers.
Seoul site footprint is the second binding constraint. Containerized MBR delivers about 60% smaller footprint than conventional activated sludge, which is often the difference between fitting inside a basement plant room and requiring a separate above-grade installation on a tight urban site (HydropureWater MBR product page). Noise, odour, and the choice between buried and trailer-mounted containers are project-specific factors that the supplied research does not quantify, so they should be sent to the Korean EPC as a checklist rather than assumed from a foreign reference project.
Step 5 — Worked sizing example for a 500-person Seoul camp
A 500-resident Seoul construction camp serves as the baseline for this calculation. The per-capita wastewater flow, peaking factor, and per-capita BOD/COD are not provided in the supplied research, so the engineer should request them from a Korean EPC before quoting the example; the structure of the calculation, however, is fixed. Once the design m³/day is known, divide it by the per-module output of 32–135 m³/day from the DF series flat-sheet MBR modules to get the module count range, then select the matching 80–225 m² module size for the required flux. The number of containers is the total modules divided by the modules-per-container figure the vendor supplies for that model.
For a 500-person camp, a design flow in the lower end of the 32–135 m³/day per-module band will typically map to a small number of standard containers, while a higher design flow pushes toward a multi-container skid. The exact modules-per-container figure is project-specific and should be confirmed with the equipment vendor, because the container arrangement changes with the chosen module size and the peak flux target set in Step 3. This example is intentionally left without numeric per-capita values to flag exactly which inputs a Korean EPC must supply.
Pre-purchase checklist for a Korean EPC
Send the Korean EPC the design population, the site's available footprint, and the discharge destination, then ask for the per-capita wastewater flow and BOD/COD values the EPC has used on similar Korean projects, because the supplied research does not contain these numbers. Request the certified effluent parameter list and limits that apply to the specific Seoul site; these are also not stated in the supplied research and are non-negotiable inputs before the design is locked. Ask for the container count, footprint, and winter-temperature derating curve for the proposed MBR model, plus reference projects in Korea that demonstrate the same model operating in cold mixed-liquor conditions.
Also confirm modules-per-container, the peak flux rating, the control philosophy, and the membrane-cleaning protocol the vendor supports, because these determine how the plant performs in the first year of operation. For a side-by-side view of how the same sizing method applies on a tropical site, see the containerized MBR STP sizing for tropical sites guide, and for an industrial wastewater example, see the MBR sizing on industrial wastewater guide.
Frequently Asked Questions
What budget should I plan for a containerized MBR STP in Seoul?
Containerized MBR pricing is project-specific and the supplied research does not contain a Korean price list, so the engineer should request a written quote that includes the container count, membrane module model, civil works, and the effluent-parameter guarantee. Ask the EPC to break out the membrane-replacement interval cost separately, because that recurring line is what most affects the lifecycle budget for a 500-person camp or residential block.
How do I choose the right MBR supplier for a Korean project?
Shortlist suppliers that can show reference projects in Korea with the same module model and a documented winter operating record, because cold mixed-liquor performance is the variable that disqualifies most non-Korean reference lists. Confirm the supplier holds local service coverage, a Korean-language control interface, and a documented spare-parts lead time, since membrane modules and air diffusers are the items that most often drive downtime.
How many containers does a 500-person camp need?
Container count depends on the per-capita wastewater flow and peaking factor, which the supplied research does not contain for Korean camps, so a numeric container count cannot be quoted from the research alone. The engineer should request the modules-per-container figure from the vendor for the chosen DF series module size, then divide the total module count by that figure once the design flow is fixed.
What Korean discharge parameters do I need to confirm before sizing?
Request the full effluent parameter list and limits for the discharge destination, including BOD, COD, total nitrogen, total phosphorus, and suspended solids, because the supplied research does not contain these values. Confirm whether the discharge enters the Han River basin or a municipal sewer, because the limits and the monitoring frequency differ between the two paths and change the biological-stage sizing.
