Large decentralized wastewater treatment system installations increase in popularity as lower-cost, high-efficiency solutions
Dennis F. Hallahan
Decentralized wastewater treatment is becoming well accepted as a viable, long-term solution for large-scale municipal and commercial wastewater projects. While decentralized systems will continue to serve rural areas outside city limits, the notion that they can serve only small, single-family homes has been changed. Some large decentralized systems handle flow rates in excess of 3800 m3/d (1 mgd).
The treatment technologies available for conventional centralized water resource recovery facilities (WRRFs) also are available in scaled-down versions. In turn, decentralized technologies are being scaled up with innovations in wastewater dispersal that can accommodate large flows efficiently.
A passive nitrogen reduction system shows promising results for onsite wastewater treatment
Josefin Hirst and Damann Anderson
Approximately 25% of the U.S., and 30% of Florida’s population, rely on onsite wastewater systems (OWS) for wastewater treatment. Nutrient loading from many sources including OWS has received increased attention. Nitrogen in particular is a nutrient of concern for water quality, and nitrate–nitrogen represents perhaps the most common groundwater pollutant from OWS.
The Florida Department of Health (FDOH) initiated the Florida Onsite Sewage Nitrogen Reduction Strategies (FOSNRS) project to research, develop, construct, and test passive onsite wastewater treatment systems to address nitrogen reduction from OWS. As part of the project, a passive nitrogen reduction system (PNRS) was developed and tested for 18 months at a 3-bedroom single-family home in Hillsborough County, just southeast of Tampa, Fla.
Penny by penny, drop by drop
Financing a $1.6 billion sanitary sewer overflow program in Louisiana
Jennifer D. Baldwin and Mark J. LeBlanc
The City of Baton Rouge/Parish of East Baton Rouge (C-P), is improving sewer infrastructure by implementing 110 projects worth approximately $1.6 billion involving wastewater treatment and storage, comprehensive rehabilitation, capacity improvements, and supplemental projects. The cost includes design, land acquisition, construction, and program administration for the C-P Sanitary Sewer Overflow (SSO) Control and Wastewater Facilities Program.
It’s the fibers: Attacking the wipes problem at the pump station
A three-phase approach to eliminating the clogging, maintenance costs, and safety issues caused by nondispersibles in the wastestream
Alec Mackie and Kevin Bates
Municipalities throughout the U.S. are seeing significant wear on their sewer pipelines and equipment due to age and a dramatic change in the types of influent. The most notable shift has been the introduction of nondispersible fabrics and other debris, which are causing significant problems in the wastestream, at pump stations, and inside water resource recovery facilities (WRRFs). While the ideal solution is to convince everyone not to flush trash and completely rebuild the system itself — for example, rehabbing all pump stations and switching to advanced treatment facilities — such a plan comes with a massive price tag.
Alternative infrastructure solutions that can quickly bring relief to collection systems, while also eliminating the costs of a complete system upgrade, must be considered. Several solutions exist on the market that are cost-effective, quick to implement, and simple to retrofit into older pump stations and WRRFs. Modern wastewater grinding systems installed directly at the pump station can effectively precondition solids — including nondispersibles — into smaller pieces so the wastewater and debris can pass through pumps without clogging.
A collection system on the cloud
A switch to mobile devices to locate and track the condition of collection systems pays off
Robert A. Bocarro, Sean O. Kilpatrick, and Darren S. Eastall
DeKalb County in Georgia currently is developing a capacity management, operations, and maintenance program for its sewer system. A cornerstone of the program is geographical information system (GIS) mapping showing the location of all manholes, gravity sewer lines, force mains, valves, and water resource recovery facilities.
An innovative approach was taken that uses a mobile app for smartphones and tablets to help inspection crews locate sewer manholes and create a comprehensive inventory and survey all manhole assets. All data are stored in the “cloud” — on remote servers accessible via the Internet — and are used to develop a geodatabase and comprehensive GIS map.