Rural Village & Resort MBR Sewage Treatment Plant

The challenge

Small rural communities, tourist villages and resort clusters often sit far from a municipal sewer. Septic tanks and simple ponds rarely meet modern discharge limits, and they release odor and nutrients into nearby rivers, lakes or coastal waters. Flows are small but highly variable: a village peaks in the morning and evening, while a resort may triple its load during the holiday season and fall to a fraction of design in the off-season.

Sites like these usually have limited land, no full-time operators and a strong need for clean, odor-free surroundings. Many also want to reuse treated water for landscape irrigation or toilet flushing. The treatment system therefore has to be compact, highly automated, tolerant of flow swings and able to produce consistently low suspended solids.

Our solution

The reference solution is a factory-built A/O + MBR package plant: an anoxic/oxic (A/O) biological process for organic and nitrogen removal, followed by submerged membrane bioreactor (MBR) separation in place of a conventional secondary clarifier. Because the membranes retain virtually all suspended solids, the biological tank can operate at a higher mixed liquor concentration (typically 6,000–10,000 mg/L MLSS), which shrinks tank volume and footprint compared with conventional activated sludge.

The plant is supplied as one or more modular tanks in carbon steel with anti-corrosion coating, stainless steel or FRP, and can be buried with access hatches or installed above ground. For design flows above roughly 100 m³/day, the reference design splits the capacity into two parallel trains so that operation can follow seasonal demand and one train stays in service during maintenance.

A PLC control panel runs the blowers, pumps and membrane filtration/relaxation cycles automatically, with level-based start/stop and alarms. Remote monitoring can be added so a regional operator can oversee several sites.

Process flow

1. Screening – raw sewage passes a mechanical fine screen to remove rags, hair and grit that would foul the membranes.
2. Equalization – a buffer tank evens out daily peaks and pumps at a steady rate to the biological stage.
3. Anoxic tank – nitrate-rich mixed liquor is recycled from the membrane tank for denitrification, using influent carbon.
4. Aerobic (oxic) tank – fine-bubble aeration oxidizes organics and converts ammonia to nitrate.
5. MBR tank – submerged hollow-fiber membranes draw permeate under low suction pressure; coarse-bubble air scour keeps fibers clean.
6. Disinfection – permeate is dosed with sodium hypochlorite before discharge or reuse storage.
7. Sludge handling – excess sludge is wasted to a holding tank for periodic hauling or, at larger sites, dewatered on a small screw press.

Scope of supply

• Integrated A/O + MBR package sewage treatment plant with tanks, internals, blowers, pumps and membrane modules
• Mechanical fine screen from our screening and filtration range
• On-site electrolytic sodium hypochlorite generator for effluent disinfection and membrane cleaning chemical
• Optional compact screw press sludge dewatering unit for sites without sludge haulage
• PLC control panel, instrumentation (level, DO, flow, TMP) and interconnecting piping within battery limits
• Installation supervision, commissioning, operator training and spare-parts package

Why this configuration works

Effluent quality is stable. The membrane is a physical barrier, so effluent suspended solids stay low even when the biology is stressed by load swings. This is the main reason MBR is widely chosen where reuse or sensitive receiving waters are involved.

Footprint is small. Eliminating the secondary clarifier and running at high MLSS typically reduces the plant area substantially compared with conventional activated sludge of the same capacity, which matters on hillside villages and landscaped resort grounds.

Operation is simple. Automated filtration, relaxation and backflush cycles, plus remote alarms, mean the plant can run with periodic visits rather than a permanent operator. Sludge age is long, so excess sludge production is relatively low.

Disinfection chemical is made on site. Producing low-concentration sodium hypochlorite from salt, water and electricity avoids transporting and storing hazardous chlorine products to remote locations, and the same chemical serves for membrane maintenance cleaning.

Capacity can grow. Modular trains allow a village or resort to start with the capacity it needs today and add a second unit as the population or room count grows.

Trade-offs should be stated plainly: MBR uses more aeration energy than some conventional processes and membranes need periodic chemical cleaning and eventual replacement. For sites with ample land and relaxed discharge limits, an MBBR or A2O plant without membranes may be more economical, and we will recommend it where appropriate.

To size a plant for your site, send the population or room count, daily flow, any available influent analysis and the required discharge or reuse standard to [email protected] or through our contact page.

Reference configuration — final design depends on site data.