accuwebsst

AccuWeb SST™

Brentwood AccuWeb SST
modules are a combination of AccuWeb fabric supported between rigid crossflow PVC sheets to provide a simple yet robust module for IFAS applications. When added to existing activated sludge systems, the effective Mixed Liquor Suspended Solids (MLSS) inventory of the system is increased without increasing solids loading to the clarifier.

Stackable "Building Blocks"
Upgrading an existing system is easy with the AccuWeb SST. These 2' x 2' x 4' "building block" modules are lightweight and rigid and can be hand-installed like other Brentwood plastic media modules ... without cranes or any expensive installation equipment. The modules are typically stacked 4 high on a footprint of 12 modules (for a total of 48 modules) above the floor and supported by Brentwood's AccuPier System.

Increased Capacity
AccuWeb SST systems add the benefits of Fixed Film systems into the suspended growth Activated Sludge process. Towers of AccuWeb SST modules are submerged in the activated sludge tanks to provide extensive surface area for biomass growth. The attached biomass population can increase the effective MLSS concentration by over 2000 mg/l, increasing organic load capacity. This also reduces F/M ratios, improving process control and stability.

Higher MLSS Without Higher Clarifier Solids Loading
Because a significant portion of the active biomass remains attached to the AccuWeb fabric rather than suspended in the mixed liquor, organic removal increases without overloading secondary clarifiers with higher solids loads. For activated sludge systems with clarifier solids loading problems, treatment performance can be maintained or even improved while reducing MLSS loading to the secondary clarifier.

Maximized Performance
The structured crossflow PVC sheets of the AccuWeb SST module are designed to maximize fluid mixing performance and oxygen transfer through the biomass on the AccuWeb fabric media. And AccuWeb SST modules are compatible with fine bubble diffusers for the most effective oxygen transfer.

Economical
Because an AccuWeb SST system improves wastewater treatment without adding aeration tankage or clarifiers, it is a low-cost solution to upgrading activated sludge plants. And the PVC-and-fabric SST modules require significantly less installation and capital costs than stainless steel frame modules.

Active Media Surface
Each loop fiber in the AccuWeb fabric is 1/16” in diameter and is made up of about 200 individual filaments, each thinner than a human hair. The total surface area available for biomass attachment at startup is up to 800 sq. ft. per cubic foot of installed media. However, dry surface area (fig. 1) does not tell the whole story. From those 800 sq. ft. of attachment points, the biomass grows underwater in 3 dimensions (fig. 3), creating flexible “branches” of non-blinding active surface area that can be measured in pounds per cubic foot, while still allowing for free flow of oxygenated wastewater through the media.

Resistant to Organic and Hydraulic Shock Loads
An “Achilles Heel” of activated sludge technology is the potential for peak hydraulic surges to “wash out” the suspended biomass from the aeration basins. With AccuWeb SST, the biomass is fixed in place, protected within the PVC sheet structure, and available to treat the incoming organic load that accompanies hydraulic surges. And unlike IFAS systems that use dispersed sponges or polypropylene cylinders, fixed-in-place AccuWeb SST media eliminates the need for the expensive pumping and screening associated with those types of systems.

Enhanced Nitrification
The biomass living on the AccuWeb fabric media increases MCRT (Sludge Age), promoting nitrification. During cold weather and where lower compliance limits are imposed, the added biomass improves the performance of nitrifying plants, or even allows non-nitrifying plants to nitrify.

Durable and Long-Lasting
AccuWeb SST modules are designed for durability and long life under the harsh conditions of an activated sludge aeration tank. The AccuWeb fabric uses high-strength polyester yarns in a proprietary lock-knit manufacturing process that fuses a knit backing and a high loop face. Even if a strand is cut or broken, the fabric will not fray or unravel. And Brentwood's structured PVC sheets and AccuPier Supports are famous for their strength and corrosion-resistance.

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