New Advanced Water Reclamation Demonstration Plant Commissioned

Padre Dam Municipal Water District (USA) opened its Advanced Water Purification Demonstration Facility in late April of this year. The demonstration facility will use advanced water purification technologies to purify and test approximately 100,000 gallons of recycled water each day.

The facility was designed to deal with California’s severe drought conditions by developing a new local water supply. The full scale system would have the potential to provide a water source that is up to 20 percent of Padre Dam’s current drinking water supply.

The new process has four treatment steps – free chlorine disinfection, membrane filtration, reverse osmosis and advanced oxidation (ultra violet light and hydrogen peroxide). Advanced oxidation is capable of killing difficult to eradicate pathogens and removing micro pollutants other processes can not treat.

If successful, the treated water would be injected into the ground water basin to be withdrawn at a later time for treatment prior to distribution as drinking water. Additionally, Padre Dam will study the possibility of expanding Padre Dam’s proposed Advanced Water Purification Project to accommodate and treat wastewater from the other agencies’ service areas in order to provide additional water supplies. This expanded program could produce up to 10 million gallons of water per day.

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Jamaica Considers Water Reclamation

Whenever there is a drought, Jamaican households go without water and crops yields are affected. There is also an increase in water-borne illnesses such as gastroenteritis. One method for overcoming the problems associated with occasions of drought in Jamaica is reclaiming water.

Reclamation of water is the treatment or processing of wastewater to make it reusable. Treatment involves the physical separation of particles followed by the use of microorganisms to remove dissolved organic matter and finally chlorine, ultraviolet radiation or ozone to make water suitable for human consumption. In the United States, this practice began at the beginning of the 19th century in Arizona and California. The recycled water was utilized to irrigate lawns and gardens and was also used as cooling water. Currently, US installations in California and Florida mainly use ozone based reclamation processes because it provides superior disinfection and micro pollutant reduction.

The benefits of recycling water are of such that many countries have embraced it in some form. Israel began using recycled water in 1965 to irrigate crops; in 1984 Tokyo used recycled water to flush toilets and in 1999 in Australia wastewater reclaimed from a treatment plant was used to irrigate vegetable crops

The Monterey (California) Regional Water Pollution Control Agency did a study in 1987 which they updated in 1998 which showed that recycled water from a nearby waste water treatment plant was as safe as well water when used to irrigate food crops. In 2003 the Florida Department of Environmental Protection stated at the 19th Annual Water Reuse Symposium that there was no evidence or documentation of any disease associated with water reuse systems in the United States or in other countries that have reasonable standards for reuse.

The reuse of water has been done safely and has been beneficial for many countries and can be beneficial for Jamaica as well. Reclaiming water can serve as a protection against droughts for Jamaicans who are consistently without water during periods of little or no rainfall. Jamaican farmers consistently face challenges with the supply of water to irrigate crops. Reuse water could be beneficial in this regard and lead to economic stability.

The challenge of water reclamation is developing the infrastructure. While the process is well proven around the world, the safe production of reclaimed water requires significant capital investment. Given the potential to help countries such as Jamaica, organizations like the UN, World Bank and similar organizations may be able to make loans to support such development.

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Australian Floods May Have Been Prevented by Water Reuse Schemes

The long Australian drought increase interest in Australia for people to talk seriously about recycling our sewage to use as drinking water. It is possible that if recycling schemes had been in place, the massive floods that followed last year might not have happened.

There are two kinds of recycled water: ‘Indirect potable reuse’ or IPR uses advanced water treatment processes such as reverse osmosis and advanced oxidation, before discharging the recycled water back into a river, reservoir, or underground prior to re-harvesting it, retreating it and reusing it. ‘Direct potable reuse’or DPR would do away with the return to the environment and the water would be pumped directly back into the city’s water supply system.

By the worst stages of the drought around 2007, it had become clear that some of Australia’s largest cities would need to adopt varying approaches to IPR in order to make full use of available water supplies. Major IPR schemes have since been partially developed in Queensland and Western Australia.

The Western Corridor Recycled Water Project (WCRWP) was developed during 2007-2010 partially as a means to supplement drinking water supplies in Lake Wivenhoe, South East Queensland. This is the primary source of drinking water supply for Brisbane and much of the surrounding area. The WCRWP uses effluent from six wastewater treatment plants, which is then subjected to advanced water treatment at three new plants at Bundamba, Luggage Point and Gibson Island.

Some of this advanced-treated water is now used for industrial purposes, but the idea of drinking it has been postponed until storage supplies drop to below 40 per cent of capacity.

That public’s negative response to the idea of drinking treated effluent is one of the reasons why DPR is not being pushed. But the floods may change the attitude about recycling. Like many reservoirs, Lake Wivenhoe has two conflicting roles. On one hand, it must provide security of drinking water supply by storing as much water as possible. One the other, it must protect Brisbane from otherwise inevitable regular flooding by maintaining as much empty space as possible. To achieve these twin objectives, the reservoir is divided into two distinct components. The bottom 1,165 billion liters is kept as full as possible for drinking water supply and the top 1,450 billion liters is maintained empty for flood control.

When operating at full capacity, the WCRWP can produce around 35 per cent of the total water consumption of Brisbane and surrounding areas. If this water was used directly as part of Brisbane’s water supply, Lake Wivenhoe could be relied upon for 35 per cent less water supply. This means that the same security of water supply could be maintained while dropping the full supply capacity of Wivenhoe by 35 per cent and thereby freeing additional space for flood mitigation. The flood mitigation capacity would be increased by around 425 billion liters, which is an increase of around 30 per cent.

In terms of water storage capacity, this new-found 425 billion liters of flood mitigation space is the same as immediately constructing a new equivalent sized reservoir, without the cost of construction and without having to relocate a single home or farm. In addition to completely avoiding the environmental impacts of new dams, it would enable less water to be captured by the dam enhancing natural flow regimes in the Brisbane River. To put this extra storage capacity into some context, a new 425 billion liter reservoir would be the fourth largest reservoir to supply drinking water to a major city in Australia.

Using the existing infrastructure of the WCRWP, water would be available immediately and there would be negligible construction costs. But most importantly, the freed-up storage space will also be immediately available to help capture and control major flooding events when they occur. With careful management, this additional storage capacity would have been sufficient to capture and contain the entire peak flow into Wivenhoe Dam that occurred between 9th and 13th January 2011. There would have been no flood in Brisbane.

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San Diego Uses Advanced Oxidation to Recycle Wastewater

In summer 2011, the City of San Diego opened the Advanced Water Purification (AWP) Facility, a small-scale, state-of-the-art facility that purifies one MGD of recycled water. The facility is one component of the City’s Water Purification Demonstration Project that is examining the safety and cost of purifying recycled water. San Diego is examining water purification as a means to develop a locally controlled, supplemental water supply. San Diego’s semi-arid region is at the end of pipelines that bring imported water from hundreds of miles away. The City needs to develop local, reliable water sources to lessen its dependence on expensive and limited imported water supplies.

All wastewater in San Diego undergoes treatment to remove harmful contaminants, making it safe enough to be discharged into the ocean. Some wastewater is diverted to the City’s recycled water facilities, where it is further treated and then used for irrigation and industrial purposes. A portion of the recycled water produced at the North City Water Reclamation Plant is sent to the AWP Facility.

To become purified water, the recycled water undergoes a multi-barrier purification process, which includes membrane filtration, reverse osmosis, and advanced oxidation with ultraviolet disinfection and high-strength hydrogen peroxide. The multi-barrier approach of consecutive treatment steps removes or destroys all unwanted materials in the water and produces one of the purest supplies of water available anywhere. The same water purification process is already used around the world.

Visitors are encouraged to tour the City of San Diego’s AWP Facility.

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Marines to Recycle Wastewater in San Diego for Landscape Irrigation

The Marine Corps Recruit Depot in San diego is pioneering a type of on-site wastewater recycling system. It will divert 10,000 gallons of sewage at the base each day, treat it to state standards and pump it through irrigation lines to the roots of landscape plants. If all works according to plan, passers-by won’t notice anything except verdant vegetation, and the technology will be deployed at military bases nationwide.

It will process wastewater from barracks and it’s expected to start working in January. The effluent will need to meet health and safety codes for a year before it’s used for irrigation around a memorial for drill instructors.

The idea for the process goes back at least to the 1970s, when a few designers started mimicking natural processes to provide electricity and clean water. Wetlands served as inspiration for removing pollutants from water, and engineers constructed various wetland-based systems that have been deployed across the country. The whole process takes place underground until the effluent is clean enough for irrigation and industrial processes where health codes permit.

Depending on the type of reuse, the water can be treated by ozone, ultraviolet, or chlorine to kill any pathogens that remain.

Numerous reuse schemes are popping up around the country as water shortages and green initiatives create a demand for these processes. Ozone and UV often play a prominent role where the water can come in contact with humans.

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West Basin to use Ozone Pretreatment for Water Reclamation

West Basin’s Edward C. Little Water Recycling Facility in El Segundo, CA will be undergoing its fourth expansion since its original construction in 1995. The facility which currently produces 30 million gallons per day (MGD) is being expanded by an additional 16 MGD.

Under the expansion, water purification facilities will be expanded to produce an additional 5 MGD of water supplied to the seawater barrier to prevent seawater intrusion and refill groundwater supplies. Other work includes an ozone pre-treatment facility, irrigation water facilities, and various solids handling facilities. The project work will cost about $60,000,000.

Recycled water brings sustainable, locally-produced water supplies to the region, making water supplies more reliable. Taking additional treated sewer water that would otherwise be discharged into the ocean will allow West Basin to help keep, on average, 50 million gallons of wastewater out of Santa Monica Bay, every day.

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