Features

August 2011, Vol. 23, No.8

Expanding Orange County’s Groundwater Replenishment System 

Lessons learned with existing system result in improvements for current expansion 

groundwater art William Dunivin, Mehul Patel, and James H. Clark

The Groundwater Replenishment System (GWRS) in Southern California is one of the world’s largest indirect potable reuse projects. Jointly funded and constructed by the Orange County Water District (OCWD) and the Orange County Sanitation District (OCSD), the 265,000-m3/d (70-mgd) GWRS supplements existing water supplies by providing a reliable, high-quality source of water to recharge the Orange County Groundwater Basin and protects the basin from further degradation due to seawater intrusion.

By recycling water, the system also provides peak wastewater flow disposal relief and indefinitely postpones the need for construction of a new ocean outfall by diverting treated wastewater flows that would otherwise be discharged to the Pacific Ocean.

The system was placed in service in January 2008, and its success has allowed for the planning and design of the initial GWRS expansion to 379,000 m3/d (100 mgd). Issues related to the original design of the AWPF that were identified during the first 30 months of operation were addressed in the expansion design and are shared here as lessons learned. Read full article (login required)

 

Rethinking decentralized systems 

A new tool for sustainable water management 

decentralized art Victor D’Amato, Jeff Moeller, and Elizabeth Striano

When visitors to the Jordan Lake Business Center (JLBC) in Chatham County, N.C., look out the window, they see an attractive courtyard and indoor atrium. What Hal House sees is a sustainable, highly effective — and multifunctional — water reclamation and reuse system. House is one of a growing number of practitioners developing new and innovative uses for decentralized wastewater systems. Read full article (login required)

 

Operations Forum Features

Side by side by side

Testing of three filtration technologies for unrestricted water reuse applications and tertiary level discharge

 

Caliskaner art Onder Caliskaner, Steve Celeste, and Bill Bennett

In 2004, the Metropolitan Wastewater Management Commission (MWMC; Springfield, Ore.) decided to add tertiary filtration to its 114,000-m3/d (30-mgd) Eugene/Springfield Oregon Water Pollution Control Facility (WPCF).

The benefits of adding filtration would be twofold. First, discharging filtered water to the river would reduce the concentration and mass of biochemical oxygen demand and total suspended solids (TSS) to help meet discharge permit limits. Second, by producing a Class A recycled water for use in irrigation and industrial processes, MWMC would help the protection of water resources. This would also reduce the thermal loads to the Willamette River by diverting a portion of the warm effluent from the river.

To select the most appropriate filtration technology, in 2008 MWMC conducted parallel pilot testing of cloth disk filtration, compressible medium filtration, and granular medium filtration. These three different filtration technologies have not previously been tested side by side for secondary effluent filtration. Read full article (login required)

 

Adding on a nutrient removal solution 

Nitrifying trickling filter provides reliable, low-energy, cost-effective tertiary municipal wastewater treatment of a lagoon effluent 

Kulick art Jerry Bounds, Jianchang Ye, Frank M. Kulick III, Phillip Gibson, and Joshua P. Boltz

The City of Newton, Miss., owns and operates a WWTP that uses an aerated lagoon system for 5-day biochemical oxygen demand (BOD) removal. In 2005, when faced with the addition of a 2.0-mg/L ammonia–nitrogen yearly average limit, it was determined that the existing aerated lagoon was incapable of producing an effluent with water quality consistent with the new permit.

To meet the new requirements, the City of Newton chose to add a nitrifying trickling filter (NTF) to remove ammonia–nitrogen from the lagoon effluent. NTFs are a reliable, robust, and cost-effective means for ammonia–nitrogen conversion. Benefits to NTFs include low energy consumption, stability, operational simplicity, and reduced solids yield. Read full article (login required)

 

Dewatering upgrades in New York’s capital 

Operational cost savings observed from belt filter press upgrades by reducing multiple-hearth furnace auxiliary fuel usage

 

Apa art Vincent L. Apa and Richard J. Lyons

About 3 years ago, the Albany County Sewer District (ACSD) replaced 30-year-old belt filter presses at its two wastewater treatment plants. As a result, the district has seen a drop in the amount of natural gas needed to incinerate its solids.

The new dewatering equipment is providing a drier cake and requiring 30% less polymer consumption. The drier cake also results in a lower natural gas (auxiliary fuel) requirement in the multiple-hearth furnaces (MHFs) used to incinerate solids. In fact, these improvements are allowing the North Plant MHFs to run autogenously at times. Read full article (login required) 

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