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DISINFECTION PROCESSES AND STABILITY REFINEMENTS TO BIOSOLIDS TREATMENT TECHNOLOGIES
Citation:
SMITH, J. E., R. Y. SURAMPALLI, R. S. REIMERS, R. D. TYAGI, AND B. N. Lohani. DISINFECTION PROCESSES AND STABILITY REFINEMENTS TO BIOSOLIDS TREATMENT TECHNOLOGIES. R.Y. Surampalli (ed.), Practice Periodical of Hazardous, Toxic and Radioactive Waste Management. American Society of Civil Engineers (ASCE), Reston, VA, 12(1):10-12, (2008).
Impact/Purpose:
to share information
Description:
This paper reviews the current US sewage sludge disinfection regulations and their associated practices; discusses the limitations of the practices; discusses the criteria employed in evaluating a new (innovative or alternative) disinfection process and both notes some processes recently evaluated and ones that. are currently being evaluated. The US regulations are designed to protect human health by minimizing the contact of humans with pathogenic microorganisms. Two types of disinfection processes are employed. Processes like pasteurization are employed to reduce pathogens below their analytical detection limits, while processes like anaerobic digestion are combined with requirements for organic matter reduction and access restrictions. Issues with the present disinfection alternatives such as their only being concerned with the presence or absence of certain pathogens like enteric viruses or Ascaris sp. are discussed and remedies suggested. Similarly, several of the current options for measuring vector attractiveness (stability) such as volatile solids reduction are in need of improvement. Work is underway to evaluate bacterial enzymatic activity and biochemical oxygen demand as possible measures of vector attractiveness. Innovative and alternative methods for disinfection are frequently proposed and it is important to understand how the stressors employed by the process contribute to its reduction of pathogenic bacteria, viruses, protozoa and parasites. For example with an alkaline disinfection process it may be possible to utilize the beneficial effects of time, temperature, pH, chemical agents like ammonia, and pressure. A two phase and batch thermophilic anaerobic digestion system, however, is able to utilize the benefits of high temperature, high levels of volatile fatty acids and free ammonia to accomplish a large reduction of pathogens. Vermicomposting and a process that uses a fumigant are currently under evaluation by the US Environmental Protection Agency and briefly discussed.
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DISINFECTION PROCESSES AND STABILITY REFINEMENTS TO BIOSOLIDS TREATMENT TECHNOLOGIES (PDF, NA pp, 35 KB, about PDF)