Features

September 2009, Vol. 21, No.9

Taking the LEED

Opportunities for change in the wastewater sector

green.jpg Velmurugan Subramanian

Although the concept of sustainable development has more public awareness and support than it did when introduced two decades ago, there is still a long way to go in implementing it. The major challenge is developing an integrated approach requiring consensus among various stakeholders. Despite this challenge, every industry is striving to adopt and implement a “green,” or sustainable, design approach in its products and projects. In this regard, the U.S. Green Building Council (USGBC; Washington, D.C.) is doing a commendable job in promoting green buildings that incorporate sustainable design, construction, and operational practices. In recent years, the rapid growth of green buildings not only is changing the built landscape but also has an impact on other industries, including the water and wastewater sector.  Read full article (login required)  

 

Greener Plants

Designing and operating a sustainable wastewater treatment plant


sustain.jpg Madan L. Arora
“Green” has become fashionable. Politicians, scientists, engineers, teachers, and social scientists use the words “eco-awareness,” “sustainability,” “greening,” and “carbon footprinting” in setting funding and research priorities and educating future generations. Policy-makers in Washington,
D.C., plan to commit billions of dollars in research and implementation of projects in the next decade and beyond, which will save Earth’s resources, such as water, energy, and materials, leaving them for future generations. This will be impossible if the present generation continues to waste and overuse the limited and ever-diminishing resources. So, the focus and the timing are right for a critical look at how these limited resources can be spent wisely.

While big industries capture the public’s attention as likely candidates to minimize their environmental footprints, there is much that wastewater treatment plants can do to achieve the same results. Through easy-to-implement common-sense approaches to design and operation, plants can save 30% or more in power usage, 60% to 80% in onsite water use, and significant amounts of water within the community if recycling projects are implemented.  Read full article (login required) 

 

Biodiesel Byproduct Can Help Control Nutrients

Glycerin may be an environmentally friendly alternative to methanol in denitrification processes

glycerin.jpg Eric Stoermer, Samuel Ledwell, April Gu, and Rob Keeling
More and more wastewater treatment facilities in the United States are required to provide enhanced nitrogen removal, which often involves carbon addition. Methanol is the
traditional source of carbon in such processes, but it is flammable and toxic, fluctuates widely in price, is derived from natural gas (a fossil fuel), and has performance limitations. Provided that its methanol content is removed, crude glycerin, a byproduct of biodiesel production, is a nonhazardous alternative to methanol.

Recent research and pilot tests have confirmed that crude glycerin is a viable carbon source for denitrification. However, it can have wide variations in chemical oxygen demand (COD), residual methanol content, fatty acid content, viscosity, gelling and freezing point, phase separation, and concentrations of suspended solids and foreign material. Moreover, many of the biodiesel facilities near wastewater treatment facilities are small and cannot consistently satisfy the volume and quality requirements of large industrial and municipal users.

Nevertheless, specialty chemical suppliers have been working with biodiesel manufacturers to overcome these problems.  Read full article (login required) 

 

Operations Forum Features

A Twist That Changed the Industry

The evolution of modern membrane systems

Membrane_Art.jpg David Klanecky
Modern pressures, such as growing populations, changing climate conditions, worsening droughts, and increasing industrial demands, are taxing freshwater supplies worldwide. Seawater desalination and wastewater reuse via membrane treatment processes are two of the solutions used more and more frequently to combat these pressures. However, had one twist in the history of membrane manufacturing been missed, membrane treatment technologies might still be a cost-prohibitive, niche technology.

While separating salt from water is anything but new, it was very costly until 40 years ago. Then, a researcher put a “twist” on how membranes were made and cut the cost of reverse-osmosis elements dramatically.  Read full article (login required)  

 

Rainy Day Calculations

A simple method for estimating inflow and infiltration using treatment plant flow monitoring reports

Kurtz_Art.jpg George E. Kurz, Brett Ward, and Gregory A. Ballard
Many small communities know they have inflow and infiltration (I/I) problems in their collection systems but lack the resources to evaluate the extent thoroughly. When these utilities obtain grant money for sewer rehabilitation work, they want to spend every penny on actual system improvements, rather than on studies to tell them how severe the problem is. In some cases, the funding agency may not even allow the money to be used for such studies. Even with these limitations, a small community can conduct some preliminary analysis in-house
to provide a baseline for measuring system improvement resulting from sewer rehabilitation.

This simple, low-cost method uses existing data and nonproprietary analytical tools available in a typical mathematical spreadsheet program to make an initial estimate of I/I in a wastewater collection system.  Read full article (login required)  

 

Fresh Is Not Always Best

An evaluation of glucose–glutamic acid stability

Fung_Art.jpg Leo C. Fung
Over the years, state and federally approved wastewater and water laboratories have been required to implement extensive quality control (QC) procedures, vastly increasing the workload, as well as expenses, associated with analyses. The rationale behind some QC measures is not always clear, nor has it been substantiated.

According to these QC, the glucose-glutamic acid standard
for the biochemical oxygen demand test must be prepared fresh just before analysis. However, laboratory testing shows that GGA solutions remain stable for weeks.

The author initiated the study described here to determine the shelf life of a laboratory prepared GGA solution under normal laboratory conditions and to observe the effect of holding time on average GGA values and standard deviations.

In the interest of efficiency, these findings indicate that the procedure for the preparation of BOD certification standards with respect to requirement for the daily preparation of GGA should be re-evaluated.  Read full article (login required)