April 2009, Vol. 21, No.4

Evaluating Greenhouse Gas Emissions

An inventory of greenhouse gases is an important piece of the sustainability puzzle   

feature1Scanlan.jpg Patricia Scanlan, Holly Elmendorf, Andrew Shaw, and Steve Tarallo

Greenhouse gas (GHG) emissions from wastewater treatment processes have become a greater concern and are increasingly being calculated and evaluated when determining the long-term sustainability of a treatment scheme. While GHG inventories are currently a topic of significant interest, they are only one factor of overall sustainability.  

The entire sustainability picture can be described using the triple-bottom-line approach. This approach can be illustrated as a “three-legged stool,” with environmental, social, and economic issues each constituting a leg. A sustainable solution adequately addresses all three of these aspects.   Read full article (login required)  


Another Reason Not To Landfill

Composting can help reduce greenhouse gas emissions  

Feature2Beecher.jpg Ned Beecher, Geoff A. Kuter, and Barbara A. Petroff

 As climate change concerns mount, agencies are beginning to look for cost-effective, carbon-neutral solutions. With this in mind, the North East Biosolids and Residuals Association (Tamworth, N.H.) analyzed the energy consumption and greenhouse gas emissions associated with two biosolids management options — composting and landfilling — being considered by a New Hampshire town. Results indicate that composting instead of landfilling creates a difference in annual greenhouse equal to removing nearly 500 cars from the road.   Read full article (login required)  


Chain Reaction

How chemical phosphorus removal really works  

spacer.gif Sam Jeyanayagam and Joe Husband

In chemical phosphorus removal, several complex reactions are influenced by such factors as pH, mixing, chemical dose, soluble phosphorus concentration, age of the hydrous metal oxide precipitate, and the extent of competing reactions. Traditionally, design engineers used an equilibrium-based precipitation mechanism to model this process, but this mechanism underestimates the role of adsorption.

Researchers recently have proposed a surface-complexation model to better explain the high levels of soluble phosphorus removal seen at full-scale operations.   Read full article (login required)  


Operations Forum Features

Incremental Improvement

Plant operators build a suitable solids handling system one project at a time  

Feature4Turley.jpg Mike Turley

From its start in 1960, the first wastewater treatment plant in the Village of New Lenox, Ill., had always had sludge and odor problems. After the plant’s final expansion in 2004, which brought the facility’s capacity to 2.4 mgd (9085 m3), original flaws were not addressed, and new headaches arose.

The wastewater department has an excellent staff with years of experience. The village’s management team was willing to allow staff to address the problems in-house. Thus began a 4-year journey toward an in-house solution to a well-functioning sludge handling system.   Read full article (login required)  


Phosphorus Removal on a Small Scale

Three biological phosphorus removal technologies are compared in Minnesota  

Feature5Friel.jpg John M. Friel, Ted K. Field, and Paige Novak

As total phosphorus limits tighten at almost all municipal wastewater treatment facilities in Minnesota — affected communities must assess biological phosphorus removal (BPR) treatment options. Each facility’s unique conditions must be measured and weighed to determine which treatment option is the best.

This article examines and compares the three most common BPR technologies used at small to medium-sized wastewater treatment facilities in Minnesota to reduce total phosphorus to about 1 mg/L: