Delhi Township WWTP Innovations Earn EPA National Award

November 24, 2009

The Delhi Township Wastewater Treatment Plant was recently selected by the EPA as a national PISCES (Performance and Innovation in the SRF Creating Environmental Success) Award winner.

Delhi Township incorporated "green" systems into modifications to its wastewater treatment plant for this first-of-a-kind system that may revolutionize wastewater solids (residuals) treatment for which HRC provided planning, design and construction engineering services.

This notable project involves changing Delhi's current residuals treatment practice to a two-stage digestion process.  The new system, which takes place in closed tanks without oxygen, incorporates a thermophilic (hotter) stage and a mesophilic (warmer) stage which produces Class A biosolids; that is, solids that are suitable for direct application to farm fields and gardens without further treatment.  Thus, the soil conditioning and nutrient content of these solids might be beneficially used.

In partnership with HESCO, who will provide the digestion process, even more "greening" will be achieved.  Methane gas produced by the process will be used to power microturbines and produce electricity for use at the Plant.  The exhaust heat from the turbines will in turn be used to heat the digesters; closing the energy loop on wastewater residuals treatment.  This system is known as "Combined Heat and Power" and Delhi's is the first in Michigan.

Another unusual aspect of this project is performance specifications were prepared for the entire system instead of its individual components because of the goal to produce Class A biosolids.

The complex piping was designed using 3-D software to minimize interferences and to provide better images of the system.  These improvements were constructed by Irish Construction, who was excited to be able to participate in this "green" initiative.

Even the facility's aesthetics present a green twist, with brick two-tone "waves" on the clarifier structures, and natural landscaping enhancements framing the site in its pastoral scene.  In fact, the Township was so green and forward thinking with its careful planning for the project that, sheep graze the surrounding rural landscape, minimizing mowing costs and fuel emissions.

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