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Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Characterization and dewaterability of raw and stabilized sludge using different treatment methods.
P Mijaylova Nacheva1, G Moeller, Chávez
1Mexican Institute of Water Technology, Paseo Cuauhnáhuac No.8532, Col. Progreso, Jiutepec, Morelos, C.P.62550, Mexico.
Summary
Sludge treatment in Mexico using composting or lime stabilization effectively reduces pathogens, making the treated sludge safe for soil application. However, helminth egg removal requires further improvement for unrestricted use.
Area of Science:
- Environmental Engineering
- Waste Management
- Microbiology
Background:
- Sludge treatment is crucial for wastewater management and beneficial reuse.
- Mexico utilizes several sludge treatment systems, necessitating a comparative analysis of their efficacy.
- Pathogenicity remains a key challenge for the safe application of treated sludge.
Purpose of the Study:
- To compare the characteristics and stabilization potential of four common sludge treatment systems in Mexico.
- To evaluate the effectiveness of anaerobic digestion, aerobic digestion, lime stabilization, and composting in reducing sludge pathogens.
- To assess the suitability of treated sludge for beneficial use, particularly in soil applications.
Main Methods:
- A pilot plant was operated for four months, testing separate systems for anaerobic and aerobic digestion, lime stabilization, conditioning, and dewatering.
- Aerobic static pile composting was conducted using locally available bulking materials.
- A turbine centrifuge was employed for dewatering stabilized sludge.
- Fecal coliform density and helminth egg removal were quantified to assess treatment efficacy.
Main Results:
- Composting yielded sludge with approximately 20 fecal coliforms (MPN/g), while lime stabilization resulted in 2 fecal coliforms (MPN/g).
- Both composting and lime stabilization produced bacteriologically safe sludge suitable for unrestricted soil use regarding fecal coliforms.
- Helminth egg removal was highest with composting (reducing Ascaris sp. from 309-430 to 3-14 eggs/g) and lime stabilization (reducing to 4-18 eggs/g).
Conclusions:
- Composting and lime stabilization are effective methods for producing stabilized sludge with low fecal coliform counts, meeting requirements for soil application.
- While pathogen reduction is significant, helminth egg removal levels in both processes do not yet meet recommended standards for unrestricted use.
- Further optimization of sludge treatment processes is needed to achieve complete removal of helminth eggs for safe and unrestricted beneficial reuse.
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