What 'Containerized MBR STP' Actually Means for a Surabaya Project
A containerized membrane bioreactor sewage treatment plant packages the full process train — screening, oil/grease separation, equalization, anoxic, aeration, submerged PVDF membrane tank, UV or chlorine disinfection, and a treated-water tank — inside one or more ISO freight containers, with the sludge line running to a holding tank and a small filter press. The sludge line runs MBR/Aeration Tank → Excess Sludge → Sludge Holding Tank → Filter Press → Sludge Cake Disposal, as documented in the 2026 DMC Education STP-MBR design guide.
The containerized format delivers three practical benefits for an East Java site. It is plug-and-play, mobile, and limits civil work to a hardstand and a small equalization buffer, per Dynatec Systems' description of containerized MBR sanitary wastewater systems. It accepts an out-of-basin membrane configuration, which allows retrofit to an existing bioreactor and simple expansion by adding more membrane skids without re-plumbing the biology.
For a Surabaya residential cluster, worker camp or small resort, three site-specific drivers shape the package: tropical ambient temperature pushing influent into the 20–35°C band, seasonal high rainfall that can lift inflow/infiltration, and the logistics envelope set by Tanjung Perak port handling and road access to the site. A defensible containerized MBR system specification in Surabaya must address all three before the supplier is asked for a price.
Step 1 — Establish Average and Peak Flow for Residential and Camp Loads
The anchor variable for the entire design is Qavg, the average sewage flow expressed in KLD; without a defensible Qavg every downstream tank, blower and membrane area is wrong, per the 2026 DMC Education guide. The first multiplication is Qp = Qavg × PF, where the preliminary peak factor PF falls in the 2.0–2.5 range — but the article should not stop there. The actual peak should be confirmed from the project's diurnal sewage pattern (camp shift change, school break, resort check-in), not left as a generic multiplier.
Translating head-count into KLD requires the client's actual occupancy profile. For a permanent residential block in Surabaya, the design driver is the number of occupied dwelling units and the planned occupancy per unit. For a construction worker camp, it is the peak head-count, the shift rotation, and whether the camp will operate 24 hours or only on day shift. For a student dormitory, the academic calendar and holiday pattern controls. For a small resort, it is peak occupancy versus average occupancy and the laundry/food-and-beverage load. The 2026 DMC Education guide treats all per-capita values as project-specific and instructs the designer to derive them from the actual flow profile, not from a textbook constant.
What the supplied research does not give is a Surabaya-specific per-capita sewage generation rate. That input must be requested from the client in writing — typically a population schedule plus an existing water-bill analysis — before the design can move past Step 1. A sizing exercise that assumes a per-capita number without that confirmation cannot be defended at a Surabaya pre-construction meeting.
| Parameter | Symbol | Unit | Typical Preliminary Value | Source |
|---|---|---|---|---|
| Average sewage flow | Qavg | KLD | Project-specific | DMC Education, 2026 guide |
| Peak factor | PF | — | 2.0–2.5 | DMC Education, 2026 guide |
| Peak flow | Qp | KLD | Qavg × PF | DMC Education, 2026 guide |
| Equalization HRT (preliminary) | HRT | hours | 6–8 | DMC Education, 2026 guide |
For sites where ground conditions restrict the equalization footprint, a buried integrated sewage treatment buffer ahead of the container can be used to keep the above-ground package compact.
Step 2 — Set Influent Characteristics and Pretreatment Envelope
Enter the biological design with a realistic envelope of BOD, COD, TSS, TKN and pH, not with a single textbook number. The 2026 DMC Education guide publishes preliminary domestic-sewage ranges that the designer can use as the design envelope: BOD 200–400 mg/L, COD 400–800 mg/L, TSS 200–300 mg/L, TKN 30–60 mg/L, pH 6.5–8.5, temperature 20–35°C. The Kaveri Watermarke MBR design PDF, used here as a single-project reference example only, lists an influent of BOD₅ 400 mg/L, COD 500 mg/L, TSS 300 mg/L and pH 7.5–8.5 for a 200 KLD domestic scheme — useful as a benchmark, not as a Surabaya site measurement.
Surabaya's tropical temperature band is double-edged. It accelerates biological kinetics, which is positive, but it also lowers oxygen-transfer efficiency, which means the same blower cannot be specified as it would be in a temperate climate. The 20–35°C envelope has to be carried forward into the aeration calculation in Step 5, not absorbed into a generic safety factor.
For Surabaya sites, FOG (fats, oils and grease) is a real risk. A construction camp canteen or a residential food court can produce a grease profile that blinds submerged PVDF membranes if it is not removed upstream. The designer should require at least one composite influent sample and a grease/oil profile, and a rotary mechanical bar screen plus a dissolved air flotation unit should be specified where the FOG load is non-trivial.
Step 3 — Size Equalization, Anoxic and Aeration Volumes
Turn the flow and influent envelope into tank volumes the container builder can price. The equalization tank is sized from Veq (m³) and a preliminary HRT of 6–8 hours, with freeboard, usable-volume and mixing allowances on top, per the 2026 DMC Education guide. The equalization buffer does more than flatten diurnal peaks: it also protects the membrane tank from hydraulic shock and gives the operator a controllable feed to the anoxic zone.
The aeration volume is set by the F/M ratio. F/M = (Q × S₀) / (V × X / 1,000), where X is the design MLSS in mg/L. The 2026 DMC Education guide keeps F/M inside 0.08–0.15 kg BOD/kg MLSS·day and MLSS inside 8,000–12,000 mg/L for an MBR — both ranges materially higher than a conventional activated-sludge plant because the membrane replaces the secondary clarifier. Operating above 12,000 mg/L is technically possible but increases mixed-liquor viscosity, oxygen demand and membrane-fouling risk, so it should be a conscious choice, not a default.
The anoxic zone must be planned by nitrogen mass balance, not by an arbitrary HRT. The internal MLSS recycle rate from the MBR/aeration tank back to the anoxic tank is the lever that actually achieves denitrification; choosing a volume without a recycle ratio is the most common small-plant denitrification error.
Finally, check that the chosen volumes fit the container envelope. Plants up to about 100 m³/day typically fit a single 20 ft or 40 ft ISO footprint; plants above that should be planned as multiple parallel containers to keep each unit road-transportable through Surabaya's industrial corridor. The supplier should be asked to confirm the modular break-point before the tank drawings are released. A modular containerized MBR system with parallel skids simplifies this planning step.
Step 4 — Calculate Membrane Area, Flux and TMP Envelope
Convert the average permeate flow into a defensible membrane area. The basic formula is Membrane Area = Permeate Flow / Flux, with flux in LMH and flow converted from m³/day to m³/h, per the 2026 DMC Education guide. The preliminary flux band is 15–25 LMH; the Kaveri Watermarke MBR design PDF cites 25 LMH as a design point for 0.1 micron PVDF immersed modules, which sits at the upper end of that preliminary band and is acceptable when the membrane supplier's own rating supports it.
TMP is held inside a preliminary band of 0.1–0.4 bar. An upward TMP trend signals one or more of the following: membrane fouling, poor air scouring, excessive MLSS or viscosity, insufficient cleaning, or excessive operating flux. Online TMP monitoring is strongly recommended for MBR systems and should be specified as a standard instrumentation item, not as an optional extra.
Specify a flat-sheet or hollow-fiber PVDF module at 0.1 micron pore size. The air-scouring rate must come from the membrane supplier's data sheet, because air-scour flow is set per m² of membrane area and varies widely by module geometry. Designing the air-scour from first principles — without supplier data — is the second most common under-specification error on small Surabaya projects. For Surabaya projects using DF series flat sheet MBR modules, the supplier's flux-vs-TMP and air-scour curves should be requested in writing before the bid is released.
Step 5 — Aeration, Blower and Permeate Pump Sizing
The utility package is the most common place small Surabaya projects are under-specified. Estimate oxygen demand as O₂ Demand ≈ 1.2–1.5 × BOD Removed, then convert to air flow using Air Flow = O₂ Required / (OTE × 0.232), per the 2026 DMC Education guide. A full oxygen balance must include carbon oxidation, nitrification, biomass synthesis, endogenous respiration, temperature and dissolved-oxygen setpoint — not only the 1.2–1.5 multiplier.
Set a preliminary blower discharge pressure of 500–700 mbar, then verify against static water depth, diffuser loss, pipeline loss, membrane air-scour requirement and a design margin, per the 2026 DMC Education guide. Surabaya's higher temperature and lower atmospheric pressure relative to sea-level temperate references both push the actual pressure requirement above the 500 mbar floor, so a 600–700 mbar preliminary range is the safer starting point for tropical designs.
Use the simplified permeate-pump formula Qp in m³/h for the average flow and add static head, friction loss and the membrane/TMP head. Specify a VFD-controlled permeate pump to stabilize flux during diurnal peaks — a standard energy-efficiency measure for Surabaya projects where electricity tariffs and diesel-generator backup both matter.
Recommend a duty/standby blower arrangement with VFD control and DO-based modulation. For projects between 50 and 200 m³/day, one duty plus one standby is usually adequate; above that, two duty plus one standby gives better turndown. The UV system on the permeate line should be selected to match the same flat sheet MBR membrane specifications envelope used elsewhere in the package, with a UV dose selected for the intended reuse or discharge application.
Step 6 — Sludge, Disinfection, Reuse or Discharge Path
Close the mass balance. Estimate excess sludge as Px = Y × BOD Removed, with a preliminary yield around 0.3–0.5 kg MLSS/kg BOD removed, per the 2026 DMC Education guide. The actual yield depends on SRT, biomass decay, influent characteristics, temperature and biological process conditions, so the supplier should be asked to confirm the yield at the design SRT before the sludge tank is sized.
Select disinfection by UV or chlorine/chlorine dioxide based on the reuse or discharge target. UV is generally preferred for MBR permeate because turbidity is already very low, which preserves UV transmittance and avoids chemical handling on site. A UV sterilizer sized to the validated dose at the design flow is the standard choice; chlorine dioxide is appropriate where a residual is required in the reuse network, such as a toilet-flushing loop, in which case a chlorine dioxide generator can be specified.
Choose between on-site dewatering and tanker offload based on site space, cake-disposal route and operator availability. For sites in the 50–200 m³/day range, a small plate and frame filter press sized to the daily dry-solids production is typically more economic than monthly tanker offload, and reduces the volume of liquid sludge leaving the site. The final cake-disposal route (landfill, composting, or third-party waste handler) must be confirmed with the receiving facility before the dewatering equipment is ordered.
Matching Containerized MBR Configuration to Project Type
Convert the engineering output into a procurement decision. Three Surabaya project types dominate the small-plant segment — permanent residential clusters, construction worker camps, and small resorts or schools — and each has a defensible default configuration. Containerized MBRs are documented as plug-and-play, mobile and easy to expand by adding more membrane skids, per Dynatec Systems, so projects with phased occupancy growth should specify extra skid space and a container that can accept a second module without re-plumbing the bioreactor.
For Surabaya sites with restricted plot size or temporary status — typically a 2–3 year construction camp — a trailer/skid-mounted container on a hardstand with truck access for periodic sludge removal is the standard answer. For a permanent residential cluster, a buried equalization tank feeding a surface containerized MBR reduces both the visual and acoustic impact on the residents, and a permanent sludge dewatering skid avoids ongoing tanker traffic.
| Project Type | Indicative Qavg Band | Container Count | Peak Factor (preliminary) | Reuse vs Discharge | Standby Philosophy |
|---|---|---|---|---|---|
| Permanent residential cluster | Confirm with client occupancy schedule | 1× 40 ft for up to ~100 m³/day; 2× parallel above that | 2.0 | Reuse for landscape and toilet flushing where the network exists; otherwise discharge to sewer | Duty + standby blower; single permeate pump with VFD |
| Construction worker camp | Confirm with camp head-count and shift pattern | 1× 20 ft or 40 ft trailer-mounted; mobile | 2.5 (camp peaks) | Tanker offload or sewer; reuse limited | Single blower with VFD; portable sludge pump |
| Small resort or school | Confirm with peak vs average occupancy | 1× 40 ft with buried equalization ahead | 2.0–2.5 depending on diurnal pattern | Reuse for landscape irrigation; discharge to sewer outside reuse network | Duty + standby blower; duty + standby permeate pump with VFD |
For all three project types, the package should be specified around a modular containerized MBR system that accepts a second membrane skid without re-plumbing, so the procurement team can negotiate the initial container count against a confirmed expansion path rather than over-sizing day one.
Frequently Asked Questions
What does a 50–200 m³/day containerized MBR cost in Surabaya?
The supplied research does not include a price for a containerized MBR delivered to East Java, and a defensible budget number for a Surabaya project must be built from a current supplier quotation. The inputs a buyer should request from each shortlisted supplier are: skid cost broken out by container count, membrane module cost, blower and UV package, freight from the point of manufacture to Tanjung Perak plus trucking to site, installation and commissioning, and a one-year spares allowance. Comparing three quotations on the same scope is the only way to keep the comparison defensible.
How long does delivery and commissioning take for a containerized MBR in East Java?
The supplied research does not include a lead time for a containerized MBR delivered to East Java. Lead time varies with container count, membrane supply chain, blower manufacturing slot and Surabaya port clearance. The buyer should request a written critical-path schedule from each supplier covering drawing approval, fabrication, factory acceptance test, shipping, site erection and commissioning, and should ask for the longest-path item in the schedule to be identified explicitly rather than accepting a single end-of-project date.
Can a single 20 ft container treat 100 m³/day?
The supplied research does not state a per-container flow limit. As a general engineering principle, a 20 ft ISO container has a finite footprint and the equalization, anoxic, aeration, membrane and permeate tank volumes must all fit inside it; whether 100 m³/day fits depends on the influent envelope, the chosen MLSS, the membrane area required and the blower package. The buyer should ask each supplier to demonstrate the layout drawing and the volume balance inside a single 20 ft container for the project's actual Qavg and Qp before accepting the configuration.
Which Indonesian discharge or reuse standard applies to a residential or camp STP in Surabaya?
The applicable standard is PERMEN LHK No. 68/2016 on domestic wastewater quality, supplemented by the local Surabaya hookup requirements from PDAM Surabaya for any sewer connection and from DLH Surabaya for any surface-water discharge. The buyer should request from the project owner a written confirmation of the discharge route — sewer, surface water, or on-site reuse — and should ask the supplier to quote the permeate quality against that specific target, rather than against a generic reuse envelope, because the Surabaya pre-construction review will be tied to the stated discharge route.
How do I choose between a containerized MBR and the WSZ underground integrated STP for the same residential project?
Containerized MBR is the right answer when the project is temporary, when the site has limited excavation depth, when treated water is needed for reuse, or when the plant must be relocated at the end of the project. The WSZ underground integrated STP is the right answer when the project is permanent, when the visual and acoustic profile of an above-ground package is unacceptable, and when the discharge route is sewer rather than reuse. The buyer should request both options from the supplier on the same influent envelope and the same treated-water target, and should select on lifecycle cost plus the discharge route, not on the headline equipment price alone. For related sizing practice in nearby Indonesian cities, the containerized MBR sizing for Jakarta guide and the containerized MBR sizing for Bandung guide give comparable worked examples with Jakarta- and Bandung-specific context.
