Features

August 2009, Vol. 21, No.8

Taking It to the Next Level

Advanced membrane filtration for water reuse applications

takingit.jpg Paul M. Gallagher and Stratton G. Tragellis

With a greater number of regions suffering severe or prolonged drought conditions, water reuse is on the rise globally and is a key part of many municipal and industrial water resource management plans. In 2005, about 19 million m³/d (5 billion gal/d) of water was reused worldwide, an amount that is expected to grow to 30 million m³/d (8 billion gal/d) by 2010 and 53 million m³/d (14 billion gal/d) by 2018. Approximately 59% of additional capacity will involve tertiary or further treatment, and the remainder will involve secondary treatment only, predominantly in emerging markets.

Population growth is fueling strong political support for water reuse, especially in the United States, Europe, and Australia. Growing environmental concerns about discharges are a factor when considering water reuse versus seawater desalination as a freshwater source. Key markets, such as China, the Middle East, and North Africa, have limited wastewater infrastructure for water collection and treatment. Building new wastewater infrastructure is expensive, and this fact dramatically increases the availability of wastewater for reuse.  Read full article (login required) 

 

Water Reclamation, Aussie Style 

A new advanced water treatment plant in Australia extends potable water resources while reducing nutrient discharges to the environment

waterreclamation.jpg Cindy Wallis–Lage, Vasu Veerapaneni, Jonathan Pressdee, and Mark Steichen

Severe drought and rapidly growing population prompted the Queensland state government in Australia to initiate several projects to secure its long-term water supply. A key project is the Western Corridor Recycled Water Project (WCRWP), which reclaims water from municipal effluent for reuse to reduce demand by industrial users of current potable water sources and potentially to replenish the local source water in the future.

Nutrients were a key concern for execution of this project because of the reclamation technologies chosen and the stringent nitrogen and phosphorus limits for any effluent discharged to the environment. However, the project team found a practical solution that not only kept reclamation costs down but also reduced the nutrient load to the receiving water.  Read full article (login required) 

 

Operations Forum Features

Siloxanes

 The hidden threat to biogas systems

siloxanes.jpg Ralph B. (“Rusty”) Schroedel Jr., Peter V. Cavagnaro, and Jerald

Although wastewater facilities have used digester gas beneficially for years, concerns about greenhouse gases, sustainability, and energy costs have created a significant emphasis on maximizing the use of the valuable gas. Recently, many facilities have seen significant buildup of a white or brown substance wherever digester gas is burned. This buildup is primarily silicon dioxide and is the result of burning siloxanes in the gas. Siloxanes create significant problems in combustion equipment, such as boilers, reciprocating engines, and turbines. Unfortunately, most wastewater facilities are not equipped to remove siloxanes from digester gas. One facility in Baltimore, however, installed a gas-conditioning system (GCS), which has helped its operating efficiency and sustainability.  Read full article (login required) 

 

Trials, Tribulation, and Triumph

 The tale of biosolids management in the Pacific Northwest

trials.jpg Maile Lono–Batura

Pacific Northwest weather is synonymous with gray skies and steady drizzle. The climate for biosolids recycling in the Northwest, however, has primarily been a fairweather tale. From innovative research projects to successful public–private partnerships, the Northwest has provided ideal end-use opportunities, active stakeholders, and a supportive regulatory framework. However, this tale would not be complete without the misadventures and conflict that prompted a new direction.  Read full article (login required)