Gulf Water Treatment (GWT) designs, supplies, installs and maintains sewage treatment plants across the UAE and GCC, with over 2,000 water and wastewater treatment units installed since 1992. The team that commissions each STP supports it through operation and maintenance.
A plant earns its capital cost only if its effluent still meets the discharge standard in year ten. We supply MBBR, MBR, SBR, extended aeration and SAFF plants within our wastewater treatment systems.
Need an STP that meets your discharge standard?
What Is a Sewage Treatment Plant?
A sewage treatment plant (STP) is a plant that removes solids, organic matter and pathogens from domestic wastewater so it can be discharged or reused. Sewage arrives from toilets, kitchens, showers and laundry across a building or development.
The treated output is known as treated sewage effluent (TSE). TSE is reused for landscape irrigation, district cooling, dust suppression and toilet flushing, and it is not drinking water.
Reuse grade matters in the UAE, where the UAE Water Security Strategy 2036 targets the reuse of 95% of treated water. A plant that treats only to discharge grade solves half the problem.
Where the intended reuse needs a higher grade than the STP alone produces, a TSE polishing plant is added downstream.
STP vs ETP vs Greywater Treatment
A sewage treatment plant handles domestic sewage, while an effluent treatment plant treats industrial process wastewater. A greywater treatment plant recovers only the lighter streams from showers, basins and laundry.
Many developments run two of the three in parallel.
How Does a Sewage Treatment Plant Work?
A sewage treatment plant works in four treatment stages plus sludge handling, and each stage removes a different class of contaminant. Undersizing any stage shows up later as odour complaints, blocked equipment or failed effluent tests.
Preliminary Treatment
Coarse and fine screens and grit chambers remove rags, plastics, sand and grit. This stage protects every pump, blower and membrane downstream, and it is the stage most often undersized in plants GWT is asked to retrofit.
Primary Treatment
Settlement removes heavy solids and floating grease. Solids drop out as primary sludge, while the clarified flow continues.
Secondary Treatment
Micro-organisms break down dissolved and suspended organic matter, which removes most of the BOD and COD. This stage decides which technology a plant uses.
Tertiary Treatment
Filtration and disinfection by chlorine or UV remove residual solids and pathogens. Faecal coliform is brought down to the level the intended reuse requires.
Sludge Handling
Sludge is thickened, dewatered on site and removed. GWT specifies the dewatering method against sludge volume and available space.
GWT Sewage Treatment Plant Technologies
The secondary treatment technology sets a plant’s footprint, effluent quality, operating cost and staffing need. Each option below gives something and trades something away.
MBBR Sewage Treatment Plant
A moving bed biofilm reactor (MBBR) holds bacteria on free-floating plastic carriers inside an aerated tank. It is compact, tolerant of load swings and the technology GWT most often specifies for buildings with peaky occupancy.
MBR Sewage Treatment Plant
A membrane bioreactor (MBR) combines biological treatment with membrane filtration in one stage. It produces reuse-grade effluent in a small footprint, at the cost of membrane cleaning and periodic replacement.
SBR Sewage Treatment Plant
A sequencing batch reactor (SBR) runs fill, react, settle and decant cycles in one tank, so no separate clarifier is needed. It handles widely varying daily flow well when the automation is reliable.
Extended Aeration Sewage Treatment Plant
Extended aeration is an activated sludge process with a long aeration time. It produces little sludge and is simple to operate, but it needs a large footprint.
SAFF Sewage Treatment Plant
A submerged aerated fixed film (SAFF) plant carries bacteria on static media in an aerated tank. It is compact with low operating demand and suits smaller communities and low-flow sites.
Comparing STP Technologies
MBBR suits changing loads, while MBR suits sites that need a high reuse grade in a small footprint. The table compares the five technologies GWT supplies.
| Technology | Effluent quality | Footprint | Sludge | Operating demand | Suited to |
|---|---|---|---|---|---|
| MBBR | Good, polishing for high-grade reuse | Compact | Moderate | Low | Hotels, hospitals, peaky occupancy |
| MBR | High, reuse grade | Very compact | Low | Higher, membrane care | On-site reuse, tight plots |
| SBR | Good to high | Moderate, no clarifier | Moderate | Higher, needs automation | Varying daily flow |
| Extended aeration | Moderate to good | Large | Low | Low | Labour camps, remote sites |
| SAFF | Moderate to good | Compact | Low | Low | Small communities, low flow |
A hotel with occupancy swings and no space for a clarifier is a different problem from a labour camp with steady flow and a spare plot. GWT specifies the technology after establishing flow profile, organic load, footprint, target effluent grade and operator cover.
GWT Sewage Treatment Plant Products
GWT supplies sewage treatment plants in five build formats, with capacity sized to each site. The right format depends on how permanent the installation is and how much site work the project can absorb.
Containerised Sewage Treatment Plant
A complete plant built inside a shipping container, factory assembled and tested before delivery. Site works are limited to connections and power, which shortens installation and commissioning.
It suits construction sites, remote projects and temporary camps that need treatment before a sewer connection exists. Short-term needs are covered through rental systems.
Marine Sewage Treatment Plant
Sewage treatment systems for vessels, barges and offshore platforms, built for motion, corrosion and tight space. Treated discharge meets the international rules for sewage release at sea, supported through GWT’s work in the marine sector.
Packaged Sewage Treatment Plant
Factory-built modular tanks delivered ready to connect. A packaged sewage treatment plant cuts on-site construction and allows larger capacities than a single container, with modules added as demand grows.
Skid-Mounted Sewage Treatment Plant
Pre-assembled on a steel frame for installation inside a plant room, basement or utility area. It suits sites where the plant has to fit within a building.
Civil-Built Sewage Treatment Plant
Built in reinforced concrete on site for large permanent installations. It is usually delivered under turnkey project execution or on a build, operate and transfer basis.
Larger schemes often include the sewer network and lifting and pumping stations that feed the plant. GWT designs these with the STP so the system is sized to one flow profile.
How an STP Project Works
An STP project with GWT moves through six steps, from the first site visit to daily operation.
- Site and load assessment. Our engineers measure flow, organic load, footprint and the standard the plant must meet.
- Technology selection. We select the technology and build format that fit your load profile.
- Design and fabrication. We complete the design, then fabricate and test packaged units before delivery.
- Installation. Units are set on prepared foundations and connected to sewer, power and reuse lines.
- Commissioning and testing. The plant is brought up to load and its effluent is tested against the agreed standard.
- Operation or handover. GWT operates the plant, services it under an AMC or hands it to your operators.
Planning an STP for a new development or camp?
Sewage Treatment Plant Applications by Sector
Sewage load varies by building type, and a plant sized on headcount alone fails where the load arrives in three concentrated hours. GWT sizes each STP against the flow pattern of the developers, contractors and operators it serves across the industries it works in.
- Commercial Buildings. High daytime flow from restrooms and food courts, near zero overnight.
- Residential Developments. Predictable flow, but strict on footprint and odour with the plant under occupied homes.
- Construction Projects. Capacity needed before a sewer connection exists, then relocated when the project completes.
- Schools and Campuses. Sharp weekday peaks and long holiday shutdowns that starve the biological stage.
- Hospitals. Pathogens and pharmaceutical residues in addition to domestic load, with no tolerance for downtime.
- Hotels. Occupancy swings plus concentrated kitchen and laundry load.
- Labour Accommodation. High organic strength at a steady rate, usually with limited operator cover.
- Oil and Gas Sites and Camps. Remote camps with variable headcount and strict discharge rules.
STP Discharge and Reuse Standards in the UAE and GCC
Treated effluent is assessed on BOD, TSS, pH and faecal coliform, with limits set by the authority where the plant operates. The limits tighten as reuse moves from restricted irrigation toward unrestricted uses.
Each GCC market sets its own rules, so the first design question is which authority the plant answers to.
| Market | Authority | What it covers |
|---|---|---|
| UAE (federal) | Cabinet Resolution No. 39 of 2021 | Treated wastewater standards for restricted and unrestricted reuse, and sludge standards |
| Dubai | Dubai Municipality | STP design guidelines, design approvals and effluent standards for irrigation reuse |
| Abu Dhabi | Department of Energy | Licensing of wastewater treatment activities |
| Saudi Arabia | Ministry of Environment, Water and Agriculture | Executive regulations for treated sewage water and its reuse |
| Oman | Environment Authority | Regulations on wastewater reuse and discharge |
GWT establishes the applicable standard and reuse grade before design begins. At early project stage that assessment is also available as a consultancy and feasibility service.
GWT Sewage Treatment Plant Services
Most STPs that fail their effluent test were built correctly and maintained badly. Blowers wear, media fouls and dosing drifts long before anything visibly breaks.
- Operation and maintenance. Daily operation, preventive maintenance, chemical dosing, sludge handling, calibration and effluent reporting.
- Annual maintenance contract. Scheduled servicing for sites that run their own operators.
- Third-party servicing. GWT services plants installed by other suppliers, starting with an independent condition assessment.
- Turnkey execution. Engineering through commissioning under one scope for developers and EPC contractors.
- Build, operate and transfer. GWT builds and operates the plant, then transfers it once performance benchmarks are met.
- Rental systems. Containerised and skid-mounted plants for temporary and emergency needs.
- Spare parts and chemicals. Spare parts and chemicals for GWT and third-party plants through the aftermarket service.
Sewage Treatment Plant Retrofits and Upgrades
An underperforming STP does not always need replacing. Where the civil structure is sound, targeted upgrades restore performance without the cost of a new plant or taking the site offline.
GWT retrofits existing STPs where discharge standards have tightened, flow has grown beyond the original design or energy use has risen on ageing blowers. An IFAS upgrade adds carriers to an existing activated sludge tank to raise capacity within the same tanks.
Every retrofit starts with a full system assessment and a written upgrade recommendation. Where equipment is the problem, repair and refurbishment restores pumps, blowers and vessels to their duty point.
Why Choose GWT as Your STP Supplier?
GWT has engineered and maintained water and wastewater treatment systems in the UAE since 1992, with over 2,000 units installed. Engineering, fabrication, installation, commissioning and operations are held in house, so one team carries a plant from design to its tenth year of service.
GWT is certified to ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018, with offices in the UAE, Saudi Arabia and Oman. Clients include developers, ports, government bodies, hospitality operators and oil and gas companies.
More delivered projects are in our case studies.
Other Wastewater Treatment Systems by GWT
Effluent Treatment Plant
Treats industrial process wastewater for discharge or reuse.
Greywater Treatment Plant
Treats water from showers, basins and laundry for flushing and irrigation.
Effluent Treatment Plant
Treats industrial process wastewater for discharge or reuse.
Greywater Treatment Plant
Treats water from showers, basins and laundry for flushing and irrigation.
Sewage Treatment Plant FAQs
Answers to common questions about sewage treatment plants in the UAE and GCC.
Need an STP that meets your discharge or reuse standard?
STP stands for sewage treatment plant. It removes solids, organic matter and pathogens from domestic wastewater so it can be discharged or reused.
Five STP technologies are in common use across the UAE, namely MBBR, MBR, SBR, extended aeration and SAFF. Each is supplied in containerised, marine, packaged, skid-mounted or civil-built formats.
STP water is the treated output of a sewage treatment plant, known in the UAE as treated sewage effluent or TSE. It is not drinking water and is used for irrigation, district cooling, dust suppression and toilet flushing.
An STP treats domestic sewage from toilets, kitchens, showers and laundry. An effluent treatment plant treats industrial process wastewater with a treatment train built around the specific industry.
Cost depends on capacity, treatment technology, build format and the effluent grade required. GWT quotes after a site and load assessment.
Yes. TSE is used across the UAE for landscape irrigation, district cooling and toilet flushing, with tighter limits for unrestricted uses than for restricted irrigation.
Yes. GWT provides operation and maintenance and annual maintenance contracts for third-party plants, starting with an independent condition assessment.
Containerised and packaged plants are factory assembled and tested before delivery, which shortens site works compared with a civil-built plant. The programme depends on capacity, format and site readiness.
Routine maintenance covers blower and pump servicing, media and membrane inspection, calibration, sludge removal and effluent testing. GWT delivers it under an AMC or a full O&M contract.
Yes. GWT supports GCC projects from its UAE head office and its offices in Saudi Arabia and Oman, designing each plant to the local authority's standard.
