Filtration and separation technologies are the core of water treatment processes, and in many cases, they can be critical process bottlenecks.
The Baia Mare Aurul gold mine in North Western Romania suffered a historic catastrophe in January 2000, when its dam burst, streaming out 100,000 cubic meters of waste water, largely contaminated with cyanide, commonly used in the process of mining gold, into tributaries of the Tisza River, a major waterway in Hungary.
The cities of Littleton and Englewood, CO, just south of Denver, share a wastewater plant — the Littleton/Englewood advanced wastewater treatment (AWT) plant located in Englewood. The 7886 m3/hr (50-mgd) Littleton/Englewood AWT plant serves more than 300,000 residents in the Denver metropolitan area. The facility also receives sewage from 21 districts within a 75 square mile service area. Plant effluent is discharged to the Denver metro area’s major watershed, the South Platte River.
Arlington County’s Water Pollution Control Plant (WPCP) in South Arlington, VA, is located on 35 acres of land squeezed into a commercial/residential neighborhood less than a mile west of Ronald Reagan Washington National Airport. The facility treats flows from nearly all of Arlington. In addition, nearly 20 percent of the plant’s flow comes from neighboring localities such as Alexandria, Fairfax County, and Falls Church. Effluent from the plant is discharged into Four Mile Run to the south, which feeds into the Potomac River and, ultimately, the Chesapeake Bay.
In 2007, Greenville, SC-based Western Carolina Regional Sewer Authority (WCRSA) conducted a rigorous performance test on a new tertiary treatment technology to assess its ability to effectively remove nitrate-nitrogen (NO3-N) without using excess amounts of methanol at its Lower Reedy Wastewater Treatment Plant (WWTP).
As a result of China’s rapid economic development in recent years, the country has implemented more stringent environmental standards. Local environmental protection departments now require most urban wastewater treatment plants (WWTP) to apply strict enforcement measures to meet Class IA effluent discharge standards according to the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002).
In spite of the recent abundance of water, many of California’s aquifers continue to balance on the edge of water scarcity. Decades of overpumping have reduced the amount of ground water available to supplement surface water resources diminished by drought. The Pure Water Monterey Ground Water Replenishment Project (Monterey Pure), addressed the need to replenish a local aquifer, by piloting Advanced Water Treatment (AWT) processes, to determine the best method to convert secondary wastewater into a pure water resource.
Now in operation for well over two years in the Malambo, Colombia, the Microclor® system has proven itself in terms of reliability and safety. According to management, the clear, vertically-oriented cells and the system’s open architecture allow for easy inspection and simplify any minor maintenance that might be required.
Veolia furnished West Deptford Energy with a BIOSTYR® Biological Aerated Filter (BAF) and Hydrotech Discfilter system, allowing effluent from a municipal wastewater plant to be reused, with a treatment capacity of 7.35 MGD, in the operation of their new “green” energy station.
Significant innovation had occurred in the 17 years since the TrojanUV4000™ was installed at the Murfreesboro Water Resource Recovery Facility. Advancements associated with system efficacy, simplified maintenance, and energy efficiency had been introduced, all of which correlate to cost savings. Such advancements can all be found in the TrojanUVSigna™ – the UV system that was selected for the upgrade.
The New Rochelle Wastewater Treatment Plant is located in the Westchester County, New York, discharging to the Long Island Sound. It serves a population base of 65,000 people and is permitted to treat average flows of up to 20.6 MGD. Operating with primary clarification and pure oxygen-based activated sludge treatment since a 1979 upgrade, the plant only removed BOD and TSS from the wastewater.
Access to clean, safe, fresh water is one of the greatest challenges facing humanity in the 21st century. By some estimates over 1.5 billion people face water scarcity issues that directly threaten their health or economic welfare on a daily basis. More concerning, the impacts of climate change and global population growth are expected to exacerbate these issues to impact over 2.3 billion people by the year 2050. These sobering facts are why six of the United Nations (UN) Sustainable Development Goals (SDGs) are focused on providing access to clean, safe water. Part of solving this challenge is reducing industrial water consumption to conserve water resources.
Wastewater filtration is often part of the tertiary treatment process that involves the final removal of suspended particles from water that has passed through both the primary and secondary treatment phases and immediately precedes disinfection. As the water passes through the filter, residual suspended material and bacteria is trapped in the filter and are removed from the filtered water. Passage can be blocked by physical obstruction, biological action, adsorption, absorption or a combination of ways. Wastewater filtration is usually the final step in the solids removal process.
With regulations increasing around wastewater effluent, the use of ultrafiltration and microfiltration systems in further polishing effluent has grown. Sand or activated carbon filters can provide a media for bacterial decomposition of nutrients, converting nitrates into nitrogen gas. The rise of water reuse applications is also fueling the increasing use of filters during the final polishing stages of the wastewater treatment process.