Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Aerobic Granular Sludge Technology: An Innovative Wastewater Treatment Solution
Aaron Glauch, Brian Bates, Manuel de los Santos
Aqua-Aerobic Systems, Inc., United States of America;
A research partnership in the Netherlands led to the development of the first full-scale application of aerobic granular sludge (AGS) technology. Now, with more than 10 years of operational experience, there are over 50 AGS plants worldwide.
Within a single tank, the AGS system creates proper conditions to reliably maintain a stable granule, without the need of carriers. Due to the layered microbial community within the granule structure, simultaneous processes take place in the granular biomass, including EBPR, and simultaneous nitrification/denitrification. Extracellular polymeric substance (EPS) biopolymer, produced by bacteria, forms the backbone of the granule. These granules enable the system to better withstand adverse conditions compared to conventional systems.
Due to the characteristics of the granular biomass and enhanced settling properties (SVI at 30-50 mL/g), the system is typically designed for 8 g/L of MLSS. Based on this and the fact that all processes occur in a single tank, the AGS system reduces footprint up to 75% and provides up to 50% energy savings compared to activated sludge systems; in addition to savings in chemical consumption when low level effluent nutrients are required. AGS is an ideal technology for plants looking to increase capacity, retrofit or upgrade, expand with limited footprint, and enhance biological nutrient removal.
In the US, a 200,000 gpd demonstration facility is in operation and three AGS pilot units have been constructed and currently commissioned at various sites.
This presentation will cover operation and advantages of the AGS technology with some performance data from various plants worldwide.
3:45pm - 4:30pm
The Enhancement of Activated Sludge Settling and Formation of Aerobic Granular Sludge Using New Hydraulic Selector Technology
Ryan Holloway1, Rudy Maltos2, Tzahi Cath2
1Kennedy/Jenks Consultants, United States of America; 2Colorado School of Mines, United States of America;
Conventional activated sludge is a simple and low-cost technology used globally for wastewater treatment. But there is a major bottleneck at these facilities, the separation of low-density poorly-settling biological floc by gravity in clarifiers. The poor settling characteristics of the floc result in oversized clarifiers, thin sludge blankets, and increased return and waste activated sludge pumping rates. To increase clarifier capacity and reduce energy consumption of existing treatment facilities, a simple hydraulic modification can be introduced to selectively remove floc with undesirable settling and biological properties.
Kennedy/Jenks (KJ) in collaboration with the Colorado School of Mines have developed a hydraulic selector technology designed to remove poorly settling floc and retain with better settling and nutrient removal characteristics. Simply, the hydraulic selector is a vacuum system with a unique intake geometry that removes solids based on their density and settling velocity. The hydraulic selector can be placed within existing process basins or secondary clarifiers and operated continuously or intermittently to remove poorly settling floc and substantially improve the sludge volume index (SVI) of the activated sludge. Initial hydraulic selector experiments have been completed using 120-L pilot-scale sequencing batch reactor (SBR) modified with the hydraulic selector technology. The reactor received and treated raw municipal wastewater for over 180 days.
Preliminary results from pilot test have demonstrated that the SVI of the sludge in the SBR could be improved from 400 mL/g to less than 50 mL/g within 60 days and carbon (BOD5 < 20 mg/L), nitrogen (NH4 < 0.5 mg/L and NOx < 15 mg/L), and solids (TSS < 20 mg/L) removal could be maintained by implementing the hydraulic selector. Additionally, aerobic granules were formed in the modified SBR, which had a much lower height to diameter ratio (H:D = 1.3) compared to the shortest currently used aerobic granule reactors (H:D > 2.5).