SEWTREAT’s Impact: Raising the Bar in Sustainable Water Management

SEWTREAT has earned its place in the spotlight, garnering nominations and accolades that underscore its pioneering role in the commercial sector. Notably, SEWTREAT has been nominated for the prestigious CEBA (Controlled Environment Building Association) Built by the Best Awards and has received recognition in the Construction World. Furthermore, SEWTREAT has been selected as the most innovative water treatment company in Southern Africa by the African Excellence Awards committee reaffirming its position as a leading innovator in the industry.

At the heart of SEWTREAT’s recent achievements lies a groundbreaking project that has transformed the landscape of water management within the commercial sector. This project centers around the Pick ‘n Pay Eastport Logistics Park , strategically situated in the Eastport Logistics Park near the O.R. Tambo airport. SEWTREAT’s innovative water treatment and reuse systems have played a pivotal role in elevating the standards of sustainable water management practices.

The impact of these innovative water treatment solutions extends beyond their immediate application. They have not only provided Pick ‘n Pay water security but have also yielded significant cost-saving benefits. Our dedication to water security, sustainability, and innovation has allowed us to establish a new industry standard. Our achievements stand as a testament to our unwavering commitment to delivering cutting-edge solutions in the field of water treatment and reuse.

The completion of a rainwater harvesting system has been strategically installed to establish a sustainable water source exclusively designed for the essential operations of refrigeration and toilet flushing within the distribution center.

Originating from the gigantic 160,000 square meter rooftop, a record-breaking expanse renowned as the world’s largest for rainwater collection, this facility’s rainwater is methodically gathered and directed towards a designated attenuation dam. This reservoir provides an impressive capacity of 3 megaliters, serving as the primary storage reservoir before undergoing treatment within SEWTREAT’s container, processing up to 300,000 Liters of water per day.

The treatment process is initiated with AFM (Activated Filter Media) filtration to capture suspended solids effectively. As the rainwater enters the filter through the inlet, it percolates through the filter bed. Suspended matter, upon contact with the filter media particles, becomes entrapped within the voids between the media. Subsequently, clean water flows through the filtration nozzles, emerging from the filter outlet in a purified state. Subsequent to AFM filtration, the water undergoes treatment with Granular Activated Carbon (GAC). This final stage involves the absorption of any organic or inorganic pollutants present in the water onto the surface of the GAC media. These pollutants are then effectively removed from the water. To further guarantee the safety of the water supply, it undergoes disinfection with Sodium Hypochlorite, satisfying the quality parameters specified by the client.

The treatment facility will feed the 1 ML underground emergency tank. During periods of drought or when the attenuation dam experiences reduced supply levels, the required water consumption is supplemented by the municipal council supply. When the emergency storage tank’s water level fall to 850 kiloliters, an automatic council actuating valve is triggered. This valve facilitates the direct flow of council-supplied water into the facility’s supply line. The council supply is also interconnected with the emergency holding tank. This interconnection activates when the water level in the emergency holding tank falls to a critical low and no supply is available from the attenuation dam. This dual supply mechanism ensures a continuous and reliable water source, guaranteeing that the facility always maintains an adequate water supply.

In situations where the municipal council is unable to provide water, the emergency storage, with a capacity of 850 kiloliters, comes into play. This reserve ensures the facility’s water needs can be met for up to 3 days without interruption.

Once the municipal council water supply is restored, it promptly begins to refill the emergency storage tank, especially during the winter months. During the summer months, the filtration facility provides sufficient capacity to replenish the emergency storage tank within 3 days.

By utilising rainwater, Pick n Pay minimizes dependence on expensive municipal water sources, promotes responsible water management, and contributes to environmental conservation. The system saves over R2 500 000 annually and has a payback period of only 22 months.

Furthermore, the truck washbay wastewater treatment facility recycles 150 000 Liters of washwater every day.

The process of the washbay’s wastewater treatment facility start off with the washwater being directed into the stormwater drain, where it undergoes an initial coarse screening. The next stage entails the utilization of a grit trap, engineered to provide a minimum retention period of one hour. This extended retention time allows for the sedimentation and settling of particulate matter within the wastewater, further purifying the effluent. Moving forward, the wastewater enters a multi-stage oil separator, designed with a minimum of two chambers. This configuration facilitates the accumulation of oil on the upper surface of each chamber, ensuring efficient oil removal from the wastewater stream.

Following the oil separator, the treated water is subjected to fine screening, with mesh sizes ranging from 1mm to 5mm before it progresses to the subsequent biological treatment stages. The heart of the wastewater treatment lies within the biological treatment process, which encompasses aerobic tanks and a clarifier. Within the bioreactors, organic materials present in the effluent are effectively digested, contributing to the purification of the wastewater. The clarifier serves a vital role in allowing the activated sludge to settle, facilitating its return to the bioreactors for continued treatment. Denitrification processes are also integrated into the clarifier, ensuring the removal of nitrogen compounds from the wastewater.

A buffer tank consistently supply water to the Activated Filter Media (AFM) and Granular Activated Carbon (GAC) filters for final polishing. These filtration stages are instrumental in achieving the desired water quality before the treated water proceeds to the final disinfection stage.

Upon completion of the treatment process, the water is directed to a final holding tank, where it is prepared for reuse in the truck washing process. This closed-loop system optimizes water utilization while adhering to stringent quality standards.

The implementation of this well-engineered biological water treatment plant has yielded remarkable results, significantly reduced water consumption and generating substantial cost savings. The recycling system achieved an impressive return on investment within 14 months, accompanied by a substantial monthly reduction in water costs, amounting to 71%. These cumulative efforts have translated into annual savings exceeding 2.2 million Rand, proving the efficiency and effectiveness of this advanced wastewater management solution.

The two projects at Pick n Pay Eastport Logistics Park together result in a combined annual savings of over R4.7 million. These savings are substantial and highlight the economic benefits of investing in sustainable water solutions. Moreover, the water conservation impact is equally impressive. The annual water savings amount to 238 million liters, which is equivalent to 95 Olympic-sized swimming pools.

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