Features

November 2007, Vol. 19, No.11

Rain or Shine, 24/7

                    

Philadelphia’s mix of water quality monitoring methods ensures around-the-clock data collection during both wet and dry weather

rainorshine.jpg Steve Ostrowski, William Richardson, Joseph Perillo, and Gary A. Burlingame

 Like many large cities, Philadelphia is working to improve the water quality of its urban stream watersheds. In accordance with the Clean Water Act and Pennsylvania’s Clean Streams Law, the Philadelphia Water Department monitors its urban watersheds to assess their overall chemical and biological health. However, the city found that traditional grab sampling did not sufficiently characterize changes in stream water quality that occur throughout a storm event. Therefore, Philadelphia invested in additional monitoring technology so that it could collect continuous water quality data regardless of the weather conditions.  Read full article (login required) 

 

Up to the Challenge      

IFAS helps growing Texas city meet discharge limits, expand capacity

uptothechallenge.jpg David R. Jackson, Leonard E. Ripley, Tod Maurina, and Sarah Hubbell

Facing new ammonia discharge limits of 3 mg/L and in need of additional capacity, the City of The Colony, Texas, began construction on its wastewater treatment plant in early 2005. The city chose to convert from contact stabilization basins to an integrated fixed-film activated sludge (IFAS) system within its existing basin volume. Upon full-scale implementation of the new IFAS basins, the plant saw immediate improvement in treatment performance and was able to comply with ammonia discharge limits for the first time in its history.  Read full article (login required)  

 

Operations Forum Features

Proper Dose     

Getting the most from your polymer
        

Proper Dose.jpg Christopher Boyd

In today’s economy, with the threats of privatization, no more federal money, and shrinking budgets, optimizing your biosolids dewatering is essential to affecting the bottom line.

After disposal costs, polymer and chemical costs are usually the greatest contributor to solids handling budgets. The
wrong polymer or the wrong polymer dose can make the bottom line swell without providing much benefit. Read full article (login required)   

 

Mechanics Versus Membranes  

Comparing mechanical and membrane solids thickening

mechanicsversusmembranes.jpg Olav Natvik, Elvio Zaghi, Chandresh Acharya, Richard Todd, and Tom Copeland

When planning the upgrade from 2.6 to 5.0 mgd (9900 to 19,000 m3/d), engineers and operators at the Oxford Pollution Control Plant (London, Ontario) compared traditional mechanical sludge-thickening technologies, such as gravity belt thickeners and rotary drum thickeners (RDTs), with an innovative use of vacuum membranes for waste activated sludge (WAS) thickening.


The side-by-side comparison reviewed the technical, financial, and operations and maintenance (O&M) requirements of thickening blended primary and WAS solids in a new building containing RDT equipment versus retrofitting existing sludge holding tanks to hold membranes to batch-thicken WAS to 4.5% and thickening the primary solids separately within the primary clarifiers.  Read full article (login required)