December 2013, Vol. 25, No.12

Echo Park Lake revival  

Rehabilitation gives Los Angeles lake fans reasons to rejoice 

Echo Park art Jim Rasmus, Hala Titus, Kendrick Okuda, Julie Allen, Larry Magura, and Andy Andrews

 Fans of Echo Park Lake have cause to celebrate. The Los Angeles landmark reopened in June following a multiyear rehabilitation focused on improving water quality. The renovation also preserves the lake’s heritage as a venue for recreational activities and community events, such as the Lotus Festival at Echo Park. And it ensures that the site remains a thriving refuge for wildlife in an urban setting. 

Echo Park Lake and its surrounding parklands offer a variety of recreational activities for local residents and visitors. The lake also serves as an off-line detention basin for nearly 324 ha (800 ac) of the Los Angeles River Watershed. Echo Park has been a part of the city’s history for nearly 150 years and is considered to be one of the city’s crown jewels of parks. Read full article (login required) 


 From surplus sludge to savings 

 Faced with more solids from its sequencing batch reactors, a medium-sized facility turns to thermal drying for a Class A marketable product   

surplus to savings art Kristi Schnell, Ken Baker, and Scott Neighbors

Bowling Green, the state of Kentucky’s third largest city, is known as the home of the Chevrolet Corvette and Western Kentucky University. Its 60,000 residents are served by Bowling Green Municipal Utilities (BGMU) for their water and wastewater needs. Residential, commercial, and industrially pretreated wastewater is collected and conveyed to the treatment facility from the City of Bowling Green and outlying areas of Warren County. Treated effluent subsequently is discharged to the Barren River. 

Recognizing the anticipated impact of growth and more stringent effluent requirements, BGMU leadership decided in 2008 to upgrade and expand the water resource recovery facility (WRRF). Four years later in June 2012, the new sequencing batch reactor (SBR) facility began operation, replacing an antiquated 40,100-m3/d (10.6-mgd) activated biofilter plant. Read full article (login required)  


Stricter seafood  

MBBR helps seafood manufacturer meet regulatory requirements 

stricter seafood art Miroslav Colic, Dennis Bentley, Maria Camila Parra, Ariel Lechter, and Jorge Garzon

 Seafood manufacturing produces high strength wastewater with high amounts of total suspended solids (TSS); fats, oils, and grease (FOG); chemical oxygen demand (COD); biochemical oxygen demand (BOD); total Kjeldahl nitrogen (TKN); and, often, high total dissolved solids (TDS). Such wastewater usually is treated by dissolved air flotation (DAF) to remove TSS, FOG, and some COD/BOD. However, in some areas where water is discharged into a lagoon or ocean, particularly in areas that depend on tourism, stricter regulations require further treatment. This treatment often is via bioreactors to remove dissolved COD, BOD, and TKN. 

A seafood processing facility in Manta, Ecuador, faced these types of conditions. By switching to a better suited flocculent and adding a moving-bed bioreactor (MBBR) polishing step, the facility was able to meet its stricter limits. Readfull article (login required) 


Operations Forum Features

Operations Challenge 2013 

Terminal Velocity’s seamless cooperation clinches its fourth-consecutive Division 1 win 

operations challenge art Jennifer Fulcher

Spectators gathered five rows deep to watch Operations Challenge 2013 teams compete. The crowd seemed to hold its collective breath as each Division 1 team took its mark. Team members sprang into action, moving from one task to the next with seamless transitions that seemed second-nature.   

Achieving fluid motion during competition takes dedication, determination, teamwork, cooperation, and confidence in the hard work preparing for the competition, said Donnie Cagle, captain of the Virginia Water Environment Association team, Terminal Velocity. As defending champions, Terminal Velocity – Cagle, Stephen Motley, Jason Truitt, Steve Poe, and coaches Elijah Smith and Bobby Williams – went on to clinch an unprecedented consecutive fourth win in Division 1. Read full article (open access)  


From private to public 

 Dayton’s journey into the biosolids processing business 

private to public art Jason Tincu, Tom Dempsey, and Bryan Taulbee

The cash register, the digital clock, the frost-proof freezer, professional football, the yo-yo, and … the insourcing of biosolids processing. What do these have in common? All were developed and innovated in Dayton, Ohio. 

In 1986, the city was outsourcing its biosolids processing operations. Prior to this, Dayton used sludge lagoons. A biosolids processing facility was built within Dayton’s Water Reclamation Facility (WRF) that was owned and operated by a private contractor for a 20-year term with 5-year review periods.   

However, with escalating unit costs and annual appropriations for biosolids processing and disposal, in addition to the absence of competition due to private ownership, Dayton staff looked inward. The city conducted a benefit–cost evaluation (BCE) to determine the 15-year life-cycle costs across a series of alternatives and used its best asset — its employees — to save costs. Read full article (login required) 


Better data for clarifiers  

Equipment used to conduct sludge settling tests can affect solids flux curves 

clarifer data art Weihua (Peter) Peng
Solids−liquid separation in secondary clarifiers is essential to a successful activated sludge process. High separation efficiency provides a clean effluent and concentrated solids. For many municipal water resource recovery facilities, clarifiers are the process bottleneck because their performance is affected by many factors, such as surface overflow rate (SOR), solids loading rate, blanket depth, underflow suspended solids concentration, sludge settling characteristics, and return activated sludge flow rate. The impact of SOR and solids loading rate on effluent suspended solids has been well documented in many studies. In addition, it has been reported that high blanket levels may contribute to higher effluent suspended solids under higher SOR conditions. Read full article (login required)