Diriyah Gate Authority Greywater Treatment Plant Project with a Capacity of 15 Cubic Meters – A Step Towards Sustainability

As part of its efforts to promote sustainability and rationalize water resource consumption, the CareWater Establishment designed, supplied, installed, and commissioned a greywater treatment plant at Diriyah Gate Authority with a capacity of 15 cubic meters per day. This project stems from the Authority’s commitment to environmental principles and the goals of Vision 2030, which prioritizes environmental protection and improving water efficiency.

Project Details:

Location: Diriyah Gate Authority.

Capacity: 15 cubic meters per day.

Purpose: Treat greywater generated by public facilities and reuse it for purposes such as irrigation and cleaning common areas, reducing freshwater consumption.

Technology Used: The plant relies on advanced filtration systems that include essential stages of greywater treatment, such as biological filters and sterilization, to ensure the quality of the treated water meets local standards.

Importance of the Project:

Water Resources Conservation: Reusing greywater reduces pressure on freshwater resources.

Cost-Effectiveness: Reducing water consumption bills in the long term.

Environmental Awareness: The project serves as a model for implementing sustainability solutions within government and private facilities.

Technology used in the Greywater Treatment Plant (Capacity 15 m³/day)

The plant relies on a multi-stage treatment technology, which includes physical, chemical, and biological processes to purify greywater and reuse it for purposes such as irrigation or toilet flushing.

Main Parts of the Plant and Their Functions

Raw Water Tank

Function: Collects greywater from various sources (such as sinks, showers).

Capacity: 5–15 m³ (underground).

Importance: Maintains a constant flow of water to the plant and helps remove large suspended particles through primary sedimentation.

Raw Water Feed Pump

Specifications:

Type: Centrifugal (304 stainless steel).

Capacity: 1 m³/hour.

Importance: Pumps water from the collection tank to the subsequent treatment units.

Coagulant Dosing Unit

Specifications:

Chemical: Coagulant (such as aluminum sulfate).

Capacity: 5 liters/hour.

Importance: Adding chemicals to collect fine particles (such as grease and impurities) for easier subsequent removal.

Multimedia Filter

Specifications:

Media: Gravel and sand.

Capacity: 3 m³/hour.

Importance: Removal of suspended solids (TSS) via mechanical filtration.

Activated Carbon Filter

Function: Absorbing organic matter, odors, and colors.

Importance: Improving water quality and removing dissolved organic compounds.

Cartridge Filter

Specifications:

Filtration accuracy: 5 microns.

Material: Polypropylene (PP).

Importance: Precise filtration to remove fine particles before the final filtration stage.

Ultra-Filtration System

Specifications:

Type: PVDF Membranes

Filtration Accuracy: 0.01–0.1 microns

Importance: Removal of bacteria, viruses, and fine suspended matter.

Chlorine Dosing Unit

Specifications:

Chemical: Sodium Hypochlorite

Capacity: 5 liters/hour

Importance: Kills microorganisms and ensures water sterilization before storage.

Aeration System

Function: Pumping air to improve dissolved oxygen and reduce odors.

Importance: Supporting biological processes and improving water quality.

Product Tank

Capacity: 5–15 m³

Importance: Storing clean water for reuse.

Control Panel

Specifications:

Control: PLC

Voltage: 380 V

Importance: Automatic control of pump and filter operation, ensuring system efficiency.

Advantages of the technology used

High efficiency: Up to 80% in removing contaminants (BOD, COD, TSS).

Operational flexibility: Handles variations in incoming water quality.

Environmentally friendly: Reuses water and reduces consumption.

Meeting standards: Treated water meets specifications for irrigation and non-potable uses.

Challenges and solutions:

The team faced technical challenges, such as selecting the most appropriate technology for the site and ensuring operational efficiency. However, advance planning in collaboration with water treatment experts helped overcome these obstacles.

The importance of graywater treatment in achieving water sustainability

Confronting water scarcity: A global challenge

The Kingdom of Saudi Arabia, like other Middle Eastern countries, is experiencing increasing water stress due to:

• Limited renewable resources (annual rainfall <100 mm).
• High per capita consumption (263 liters/day compared to 150 liters/day globally).
• Growing population and industrial activity.

In this context, treating graywater (generated from sinks, showers, and laundry) is a proactive solution that reduces reliance on groundwater and desalination plants by up to 40%, according to studies by the Saudi Water Research Center (2023).

Multiple Benefits: Environment, Economy, Society

A. Environmental Protection:

• Pollution Reduction: Diverting graywater from the public network prevents it from mixing with sewage, reducing the load on central treatment plants.
• Ecosystem Preservation: Reusing treated water to irrigate green spaces (such as the Diriyah Gate Gardens) supports plant diversity and reduces freshwater depletion.

B. Tangible Economic Savings:

• Reducing operational costs: The cost of treating a cubic meter of graywater is 1-2 riyals compared to 5-8 riyals for desalination.
• Save 50% on water bills for large facilities, according to the Saudi Water Efficiency Program.
• Long-Term Investment: The expected operating lifespan of treatment plants is 15 years, with minimal periodic maintenance.

C. Raising community awareness:

• A Practical Model for Sustainability: Projects like the “Diriyah Gate” demonstrate the feasibility of the technology and encourage individuals and the private sector to adopt it.
• Achieving the goals of Vision 2030: Reducing per capita consumption by 43% by 2030 through reuse projects.

Practical Applications of Treated Water

The water produced by treating graywater is used for:

• Irrigating plants, saving 30% of irrigation consumption
• Washing parking lots, providing a 100% alternative to potable water
• Cooling air conditioning systems, saving 25% of monthly consumption

Challenges and Innovative Solutions

Despite the benefits of designing and building graywater treatment plants, this technology faces challenges such as:

Misconceptions: “Treated water is unsafe.”

Solution: Publishing the results of periodic tests that prove compliance with the Saudi Standards, Metrology and Quality Organization (SASO) standards.

Initial Cost: Installing the plant requires an initial investment (50,000 riyals for a small plant).

Solution: Feasibility studies show cost recovery within 3-5 years through bill savings.

Conclusion:

The Diriyah Gate Water Treatment Plant is not just a technical facility; it is a proactive model that embodies the Kingdom’s transformation from a consumer-driven economy to one that recycles resources. Adopting such projects is an investment in a more sustainable future, where every drop of water becomes a source of development. Therefore, this project represents a practical step toward achieving water sustainability. It reflects the role of government agencies in adopting environmentally friendly projects. We hope it will serve as an incentive for more similar initiatives in the future.

Read more about: The future of graywater treatment

The CareWater Establishment is committed to providing integrated and innovative solutions in the field of graywater treatment by designing, installing, and operating plants that utilize the latest advanced technologies and comply with the highest environmental standards. Thanks to its specialized team and extensive experience, the Foundation has become the first choice and most prominent name in the field of water treatment in Saudi Arabia, combining quality, efficiency, and commitment to sustainability standards. The Diriyah Gate project is a model that embodies its leadership and the confidence of both government and private entities.

Our experts are happy to answer all inquiries related to graywater treatment plants, whether in terms of design, operating mechanism, economic feasibility, or operation and maintenance requirements. At CareWater, we believe that smart solutions begin with a thorough understanding of each client’s needs. That’s why we provide direct access to specialized engineers and consultants with extensive experience in water treatment technologies.

Whether you represent a government agency, a commercial facility, or a residential project seeking to reduce water consumption and promote sustainability, we are ready to provide a customized study and a detailed technical and financial proposal that outlines the benefits, costs, and expected returns of establishing a graywater treatment plant that suits your facility.

We also offer after-sales services, including periodic follow-up, preventative maintenance plans, and high-performance plant maintenance to ensure continued efficient operation. Because we believe that excellence can only be achieved through trust, we have been committed to building long-term relationships with our clients since our inception, based on quality, transparency, and commitment.