An all-inclusive system converts wastewater to consumable water.
Water, in many places, is becoming a matter of life and death. Many nations, especially developing nations, face a serious shortage of clean water and are most susceptible to water related disease. It has been reported that almost a billion people in the world lack access to safe water supplies (1), 3.575 million people die each year from water-related disease (2), and in developing countries, 90 percent of wastewater is discharged into rivers or streams without any treatment (3). Even developed nations—including the U.S., Spain, Australia and Singapore—are not exempt from clean water shortages. Unfortunately, problems do not end with water-related disease and water shortages, according to a report released from the Defense Intelligence Agency (DIA) in early 2012 (4).
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| Figure 1. Advanced integrated water recycling system |
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| Figure 2. Bacteria consortium (pellets and liquid) |
This assessment concludes that global water-related challenges encountered within the next 10 years may contribute to instability in states important to U.S. national security interests. Together with other issues (poverty, social tensions, environmental degradation, ineffectual leadership and weak political institutions), global water problems may contribute to social disruptions that could result in political collapse.
Because most water consumed by humans and industries is discharged to municipal wastewater treatment plants, rivers, streams or underground, it would be advantageous to capture and treat this wastewater for reuse. This approach helps alleviate both the water shortage and water disease problems. Ideally, a technically and economically feasible system would be used to convert this wastewater to reusable water for numerous applications—not limited to households, gardens and irrigation.
Several technologies have been explored to convert wastewater to reusable water (5). Most include physical, chemical, biological and disinfection processes, but the costs per gallon of wastewater treated is typically high. In addition, they only focus on municipal wastewater. To meet the demands of clean water for the world, a cost-effective system that is able to convert municipal and industrial wastewater into reusable water is required.
An Integrated Water Treatment System
Two companies developed and recently commercialized an advanced, integrated water reclaiming system (see Figure 1) to convert municipal/industrial wastewater into usable water with zero fecal Coliform and zero total Coliform (6). Because wastewater quality varies as a function of its source, the developed system incorporates a robust, broad spectrum bacteria consortium (developed and optimized by the two companies and shown in Figure 2), which can target specific contaminants for removal that are typically found in municipal wastewater and other industrial wastewater sources. The system has great flexibility to treat different wastewater streams for adherence to the ever-evolving U.S. Environmental Protection Agency standards.
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| Figure 3. The process diagram of the integrated water reclaiming system |
A simplified process diagram of the treatment system is shown in Figure 3. On the front end of the system, wastewater is pumped into an equalization tank for stabilization and then transferred into a settling tank for separation of inorganic solids from solution. From there, the supernatant from the settling tank is conveyed into a biofilm reactor, which is seeded with a proprietary bacteria consortium. The bacteria consortium produce uniform biofilm (see Figure 4) on a media substrate (see Figure 5) packed in the bioreactor. It is this bacteria-laden biofilm that consumes most of the waste stream contaminants in an aerobic condition.
The effluent from the bioreactor is pumped into a filter for polishing before the final disinfection process. Treated water from the disinfection process is ready to be used for households, gardens, irrigation and other applications. While the proprietary bacteria consortium serve as the heart of the treatment system, the sophisticated data acquisition and control system function as the brain.
The integrated control system (see Figure 6) provides for autonomous operation through its ability to self regulate based on user-defined set points and continuous monitoring and control, which is beneficial for isolated installations. This advanced functionality of the system guarantees performance to better meet the application’s requirements. Table 1 shows the results of treating a local municipal wastewater stream using the integrated system. The untreated wastewater and recycled water are shown in Figure 7.
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| Figure 4. Biofilm | Figure 5. Media |
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| Figure 6. Automatic control system | Figure 7. Recycled water (left) and wastewater (right) |
The cost range (based on 1,000 gallons of wastewater reclaimed) is 0.5 to 1.5 U.S. dollars and 0.4 to 1.3 U.S. dollars for capital and operation and maintenance, respectively. This cost range is significantly less than existing systems for converting wastewater to recycled water (5). From Table 1, the BOD5 and TSS of reclaimed water are better than the minimum water quality standards for reclaimed water mandated by most states in the U.S. (7). The fecal and total Coliform concentrations are also consistently below those maximum acceptable limits.
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| Table 1. The integrated wastewater treatment system's contaminant removal |
Many of these integrated systems have been delivered worldwide, and a new high-volume system is being fabricated in the U.S. To better meet different water treatment demands and solve the world shortage problem, the team is currently working to optimize the system in terms of technology and cost. The following items are being considered:
- Pumps and fluid transport
- Air blowers and oxygen delivery systems
- Media/bacteria support substrates
- Tank and hydrodynamic design
- Processing monitoring and control system
- Data acquisition system
It is anticipated that this integrated system is in a great position to generate more reuse water for the world.
Reference:
- UNICEF/WHO. 2008. Progress on Drinking Water and Sanitation: Special Focus on Sanitation.
- World Health Organization. 2008. Safer Water, Better Health: Costs, Benefits, and Sustainability of Interventions to Protect and Promote Health.
- http://matadornetwork.com/change/40-shocking-facts-about-water/.
- Global Water Security, INTELLIGENCE COMMUNITY ASSESSMENT, ICA 2012-08, 2 February 2012.
- Water Reuse Association, 2011 Potable reuse conference, Nov. 13-15, 2011, The Westin Diplomat Resort & SPA, Hollywood, Fla.
- APHA, AWWA and WEF, Standard Methods for the Examination of Water and Wastewater, 21th Edition 2005.
- U.S. EPA, Guidelines for Water Reuse, EPA Number: 625R04108, September, 2004.