In 1949, the Izaak Walton League produced a film showing water conditions around Alexandria. Back then, raw sewage flowed directly into Four Mile Run, Hunting Creek, Hooffs Run, and the Potomac River. The film documented putrid clogged tributaries and a foul mix of bubbling, decomposing waste in discolored waters. Shorelines were devoid of wildlife and birdsong, and tests showed dozens of disease-causing pathogens. Water pollution was so bad that airborne passengers from D.C. could look down and see the sludge. Less than a decade later, Alexandria began work to treat wastewater, and today, the Alexandria Sanitation Authority is one of the most advanced water treatment facilities in the world. Here's how…

• From its founding in the 1700s until the late 1930s, the entire National Capital region handled its waste by dumping it directly into the Potomac River and its streams and tributaries. There was even an outhouse overlooking the river at the end of Queen Street . The untreated sewage posed an enormous public health threat. Cholera, hepatitis and dysentery are just some of the waterborne diseases associated with untreated sewage.

• In 1952, the Alexandria City Council created the City of Alexandria Virginia Sanitation Authority - now known as ASA - for the purpose of constructing, operating and maintaining a sewage disposal system to serve Alexandria and portions of Fairfax County. In 1956, the original plant went into service and the first sewage was treated - and it hasn't stopped since.

• Starting in the late 1960s, policymakers began imposing stricter and enforceable water quality requirements. The blueprint for a cleaner Potomac River and Chesapeake Bay included the Potomac Embayment Standards in the early 1970s, the original Chesapeake Bay Agreement and its many amendments, and the State Water Control Water quality standards.

• The landmark Chesapeake 2000 Agreement pledged to restore water quality by 2010 and three years after its signing, the region's governments set dramatic nutrient reduction targets throughout the watershed.

• ASA took deliberate and focused action to meet those targets. You see the results today in ASA's state-of-the-art, advanced water treatment facility that began initial operations in 2002/2003.

• In 2006, Virginia set new rules that call for a more dramatic reduction in nitrogen effluent levels by 2011. At the same time, the amount of solids in the waste stream has increased by two-thirds over the past ten years. This requires new approaches to handle the waste, such as offering life-giving, renewable material that farmers and landscapers use, or converting it to a renewable energy source.

• In the coming years, ASA will be upgrading its facility so it can continue to make Alexandria a great place to live, work and start a business while operating sustainably.