Aerobic treatment systems - LUCAS® systems for wastewater treatment
LUCAS® systems for advanced aerobic wastewater treatment solutions.

What is aerobic wastewater treatment?
Aerobic wastewater treatment is a biological process used to treat sewage and industrial wastewater by using oxygen to break down organic matter. Unlike anaerobic treatment, which operates without oxygen, aerobic treatment relies on the presence of oxygen to support the growth of microorganisms (aerobic bacteria) that consume the organic pollutants in the wastewater.
One of the most common forms of aerobic treatment is the activated sludge process, in which wastewater is mixed with a suspension of microorganisms in an aeration tank. These microbes feed on the organic matter, and the mixture is then sent to a settling tank where the biomass separates from the treated water. A portion of this biomass is recycled to maintain the microbial population.
This activated sludge process not only significantly reduces the amount of organic matter and waste but also transforms them into stable forms, such as carbon dioxide and water, making the effluent safer for discharge or further treatment. The digestion of these organic pollutants, particularly in activated sludge systems, ensures effective and reliable treatment of sewage and other wastewater types
Activated sludge-based pollution removal
Waterleau has successfully implemented biological processes using oxygen to break down the organic contaminants and other pollutants like nitrogen and phosphorus almost everywhere.
From sewage treatment plants treating wastewater of millions of people, to aerobic post-treatment of brewery bio-effluent, our cyclic activated sludge-based LUCAS® aerobic solution will help you meet discharge regulations, reducing discharge costs as well as the environmental footprint of your activities.
LUCAS® Activated Sludge wastewater systems
Waterleau's LUCAS® System offers a range of innovative solutions for biological wastewater treatment, all based on the activated sludge process. Each system is tailored to meet specific industrial and municipal needs, focusing on efficiency and sustainability.
- Sequencing Batch Reactor (LUCAS® Cyclic Activated Sludge)
- Granular Aerobic Sludge Reactor : LUCAS® AGS
- Carousel oxidation system (LUCAS® Carousel)
- Extended Aeration System (LUCAS® Extended Aeration)

LUCAS® Cyclic Activated Sludge
The LUCAS® Cyclic Activated Sludge is an ultra-compact and intelligent solution for the treatment of industrial and municipal wastewater. It combines the advantages of conventional technology and the Sequencing Batch Reactor (SBR) technology.
The modular system of the LUCAS® technology offers a high-performance, low-cost and compact solution for the treatment of every type of wastewater, organic concentration and nutrient load, even with strong variations in water flow.
In its most typical design, the LUCAS® Cyclic Activated Sludge consists of 3 hydraulically interconnected tanks with common walls and identical configuration. Each tank alternates (cyclic) one of the 3 processes of biological wastewater treatment: accumulation, regeneration and sedimentation.
The optimal alternation of the 3 processes in each of the tanks depends on the wastewater characteristics during each phase and is controlled by our control & monitoring system, ensuring maximum efficiency and limiting operational costs.
Improved settling with LUCAS® AGS
Aerobic Granular Sludge or AGS is a type of microbial biomass that forms compact, dense granules rather than loose flocs like in traditional activated sludge. These
granules enhance the efficiency of biological treatment processes by
improving settling properties and reducing the footprint of treatment
plants.
The LUCAS® AGS system is an advanced LUCAS® Cyclic Activated Sludge system designed to increase effluent withdrawal and sludge settling based on the Waterleau AGS process. This AGS process optimizes the breakdown of organic pollutants, nitrogen, and phosphorus, ensuring efficient and sustainable treatment: by growing AGS in your system, no need to dose chemicals like FeCl3 to remove the P content. Carbon, Nitrogen and Phosphorous are removed biologically by these aggregates of bacteria, simultaneously.
The LUCAS® AGS system's compact design significantly
reduces the footprint, making it suitable for space-constrained
environments. Additionally, the advanced cyclic operation minimizes
energy and chemical usage, leading to a lower total cost of ownership.
The embedded AGS process in the compact and cost-effective LUCAS® Cyclic Activated Sludge technology of makes it a sustainable solution for modern wastewater management.
Advantages LUCAS® AGS
- High Settling Velocity & Surface Loading Rate
Densified sludge enables compact plant design with efficient solids-liquid separation.
-
Energy-Efficient Nutrient Removal
Simultaneous removal of organic pollutants, nitrogen, and phosphorus with lower energy consumption. -
Reduced Footprint & Civil Costs
Smaller tank volumes translate into lower construction and infrastructure expenses. -
Chemical-Free Operation
No need for coagulant dosing, minimizing operational complexity and chemical costs. -
No Need for Granular Seeding
Natural granule formation eliminates the requirement for external biomass seeding. -
Standard Start-Up Time
Follows a conventional biological start-up timeline—no special procedures needed

LUCAS® Carousel
The LUCAS® Carousel wastewater treatment technology is our conventional and proven-concept aerobic wastewater treatment system.
Whereas in the LUCAS® Cyclic Activated Sludge systems, the 3 processes of biological treatment alternate in each of 3 hydraulically interconnected compartments, in the LUCAS® Carousel system, the activated sludge reactor tank combines accumulation and regeneration, while settling takes place in a dedicated and separated clarifier or sedimentation tank.
The bioreactor design allows nitrification-denitrification and removal of phosphorus in one single reactor. After treatment, the purified water is separated from the activated sludge in a clarification step.

LUCAS® Extended Aeration
The LUCAS® Extended Aeration is our biological treatment design in case no activated sludge from secondary treatment is fed to the sludge from primary treatment.
With a higher concentration of inert solids, longer mixing time is required for the removal of bio-degradable organic waste. Mixing must be provided by aeration or mechanical means in order to sustain the biological process.
With the longer detention time, high removal efficiency can be achieved.
More about our LUCAS® AGS aerobic wastewater treatment?
Are you looking for an advanced aerobic municipal wastewater treatment solution? Our aerobic LUCAS® AGS technology may be the answer you've been searching for.
Frequently asked questions
What is the process of aerobic wastewater treatment
- Pretreatment: This initial phase removes large solids and grit from the wastewater to prevent damage and clogging in the treatment systems downstream.
- Primary Treatment: In this stage, physical settling allows for the removal of settleable solids. Although not always classified under aerobic processes, primary treatment is essential for reducing the load on subsequent aerobic stages.
- Secondary Treatment (The Core Aerobic Process):
- Aeration Tank: The heart of the aerobic treatment process is the aeration tank, where wastewater is mixed with a culture of aerobic microorganisms. Air or pure oxygen is introduced into the mixture, providing the necessary oxygen for the microorganisms to metabolize the organic pollutants
- Biological Oxidation: As these microorganisms consume the organic matter, they convert it into carbon dioxide, water, and biomass. The process also breaks down nutrients like nitrogen and phosphorus, which are common in sewage and certain industrial wastewaters.
- Settling Tank: After aeration, the mixture moves to a settling tank (also known as a secondary clarifier), where the biomass (now referred to as activated sludge) settles out from the treated water. Part of this sludge is recycled back into the aeration tank to maintain a high concentration of microorganisms, while the excess is removed for further treatment or disposal.
- Tertiary Treatment (Optional): Depending on the required quality of the final effluent, the water may undergo additional treatment steps such as filtration, disinfection, and nutrient removal. These processes can further reduce pollutants and prepare the water for discharge or reuse.
What are the key advantages of Aerobic wastewater treatment?
Aerobic wastewater treatment offers several key advantages that make it a preferred choice for many municipal and industrial applications. These benefits stem from its operational principles and the efficiency of the biological processes involved. Here are the main advantages:
- Effective Organic Matter Reduction
- High-Quality Effluent
- Nutrient Removal
- Flexibility and Scalability
- Odor and Pathogen Reduction
- Energy Production Potential
- Regulatory Compliance
- Public Health and Environmental Protection
Which types of industries are best suited for aerobic wastewater treatment?
Aerobic wastewater treatment is versatile and can be applied across a wide range of industries. This method is particularly well-suited for sectors that produce organic-rich wastewater but with lower concentrations of solids or those that are easily biodegradable.
Some possible industries are: Food and beverage, Textile industry, Pharmaceutical, Pulp an paper, municipal sewage treatment,....
How does aerobic wastewater treatment differ from anaerobic treatment?
Aerobic and anaerobic wastewater treatment processes are both biological methods used to treat wastewater, but they operate under different conditions and serve different needs. Understanding the distinctions between these two processes is crucial for selecting the appropriate treatment method for specific wastewater characteristics and treatment goals. Here's how they differ:
Oxygen presence:
- Aerobic Treatment relies on the presence of oxygen. In this process, aerobic microorganisms (those that require oxygen to live) break down organic pollutants in the wastewater. Air or oxygen is supplied to the system to maintain an aerobic environment.
- Anaerobic Treatment operates in the absence of oxygen. Anaerobic microorganisms (those that do not require oxygen to live) digest the organic material and produce methane and carbon dioxide as by-products.
Energy consumption and production:
- Aerobic systems tend to consume more energy, primarily because of the need to constantly supply oxygen to the treatment process, often through mechanical aeration.
- Anaerobic systems are generally more energy-efficient in operation and can even produce energy in the form of biogas (methane), which can be captured and used as a fuel.
Treatment efficiency and speed
- Aerobic Treatment is typically faster than anaerobic treatment due to the rapid metabolism of aerobic bacteria in the presence of oxygen. It is highly effective for the reduction of organic pollutants and nutrients over a shorter period.
- Anaerobic Treatment is slower but is highly effective for treating high-strength wastewaters with high concentrations of organic matter. It is often used as a pretreatment step or for specific industrial applications.
Sludge Production
- Aerobic processes usually produce more sludge than anaerobic processes. The sludge is the biomass generated from the digestion of organic materials, which requires further treatment and disposal.
- Anaerobic treatment produces less sludge, which is an advantage in terms of sludge handling and disposal costs.
Applications
- Aerobic systems are commonly used for the treatment of municipal sewage and industrial wastewaters that are low to medium in strength. They are suitable for smaller-scale applications and where high-quality effluent is required.
- Anaerobic systems are ideal for treating high-strength industrial wastewaters from sectors like food processing, breweries, and dairies. They are well-suited for large-volume applications where energy recovery is a priority.
Facility Size and Layout
- Aerobic treatment systems often require more space due to the need for aeration tanks and equipment.
- Anaerobic systems can be more compact, especially high-rate anaerobic reactors, making them suitable for locations with limited space.
What maintenance is required for aerobic wastewater treatment?
Maintaining an aerobic wastewater treatment system is crucial to ensure its efficient operation, compliance with environmental regulations, and prolongation of its service life. Regular maintenance helps in preventing system failures, reducing the risk of pollution, and minimizing operational costs.
1. Aeration Equipment Maintenance
- Inspect and Clean Air Diffusers
- Check and Repair Blowers
2. Monitoring and Adjusting Microbial Population
- Control Microbial Health
3. Sludge Management
- Monitor Sludge Volume
- Sludge Treatment and Disposal
4. Cleaning and Unclogging
- Pipes and Channels
- Settling Tanks
5. System Inspections and Mechanical Maintenance
- Regular Inspections
- Electrical Systems
6. Process and Quality Monitoring
- Regular Sampling and Testing
- Adjustments Based on Monitoring Results
7. Emergency Preparedness
- Backup Systems
- Spill Response Plan
Waterleau provides all services to keep your treatment plant running as designed. From design to fully outsourced operations, we take care of your water needs, so you can focus on value creation.
What happens to the sludge produced in the process?
The sludge produced is typically dewatered and then either disposed of in landfills, used as fertilizer (if safe), or further treated, such as through anaerobic digestion to reduce volume and produce biogas.
Are there different configurations of activated sludge systems?
Yes, there are various configurations, including conventional activated sludge, extended aeration, and sequencing batch reactors (SBR). Each configuration serves different treatment needs and operational efficiencies.
Why is oxygen important in an aerobic treatment system?
Oxygen is essential in aerobic systems because it supports the growth of microorganisms that break down organic matter in the wastewater. Without sufficient oxygen, these processes would slow down or stop, leading to poor treatment performance.
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