An Odor Odyssey: Review of Scientific Progress toward Eliminating Odorant Emissions from Philadelphia's Biosolids

Abstract: The Philadelphia Water Department (PWD) has for six-years intensively studied the odor characteristics of its biosolids cake to identify effective mitigative measures for odor control. Between 2001 and 2006, PWD, working with Bucknell University and several other research partners, demonstrated that biosolids odors arise from the release of total volatile organic sulfur compounds (TVOSC) during protein metabolism, when shear forces within centrifuges both release food for decomposition and suppress methanogenesis. A peak odorant intensity results several days after dewatering. Concentrations of TVOSCs may at times be six orders of magnitude above the ED50 concentration. No single mitigative measure provides compelling control over odorant production. Examined alternatives include 1) addition of chemical conditioners (ferric chloride); 2) use of alternative dewatering polymer products; 3) changes to centrifuge operational parameters (speed and torque); 4) treatment after post-dewatering with various mineral, alkaline and enzyme products; 5) evaluation of storage and effects of freezing/thawing and wetting/drying on odors; 6) supplementation of digesters with nutrients and enzymes. Steps PWD has taken in response are: matching the point of low odor in biosolids to its use at sensitive sites; blending high carbon coal ash to reduce odorant emissions; providing temporary covered storage of piles to prevent rainfall capture and biosolids freezing

Perspectives on ENCODE

The Encylopedia of DNA Elements (ENCODE) Project launched in 2003 with the long-term goal of developing a comprehensive map of functional elements in the human genome. These included genes, biochemical regions associated with gene regulation (for example, transcription factor binding sites, open chromatin, and histone marks) and transcript isoforms. The marks serve as sites for candidate cis-regulatory elements (cCREs) that may serve functional roles in regulating gene expression1. The project has been extended to model organisms, particularly the mouse. In the third phase of ENCODE, nearly a million and more than 300,000 cCRE annotations have been generated for human and mouse, respectively, and these have provided a valuable resource for the scientific community.11Nsciescopu

Expanded encyclopaedias of DNA elements in the human and mouse genomes

AbstractThe human and mouse genomes contain instructions that specify RNAs and proteins and govern the timing, magnitude, and cellular context of their production. To better delineate these elements, phase III of the Encyclopedia of DNA Elements (ENCODE) Project has expanded analysis of the cell and tissue repertoires of RNA transcription, chromatin structure and modification, DNA methylation, chromatin looping, and occupancy by transcription factors and RNA-binding proteins. Here we summarize these efforts, which have produced 5,992 new experimental datasets, including systematic determinations across mouse fetal development. All data are available through the ENCODE data portal (https://www.encodeproject.org), including phase II ENCODE1 and Roadmap Epigenomics2 data. We have developed a registry of 926,535 human and 339,815 mouse candidate cis-regulatory elements, covering 7.9 and 3.4% of their respective genomes, by integrating selected datatypes associated with gene regulation, and constructed a web-based server (SCREEN; http://screen.encodeproject.org) to provide flexible, user-defined access to this resource. Collectively, the ENCODE data and registry provide an expansive resource for the scientific community to build a better understanding of the organization and function of the human and mouse genomes.11Nsciescopu