Walker Process Equipment
                            A Division of McNish Corporation

Office and Factory
840 N Russell Ave
Aurora, IL 60506


Back to Product Search

Digester Mixing


The vertical shaft agitator by Walker Process provides a low energy solution for thorough, effective and maintenance free mixing for anaerobic digesters. Learn More about this product.


GasLifter digester mixing systems provide thorough mixing of the digester contents to increase digestion efficiency and control grit and scum accumulations. The GasLifter recirculates digester gas from the gas dome through a compressor to boost pressure, and then releases it into an eductor tube to create a gaslift pumping effect. Control housings complete with compressor, gas controls, and safety devices are weatherized and cover or remote mounted. Learn More about this product.

Digester Covers

Fixed Type

Fixed Type
Fixed covers are used in digesters with no variation in total volume and are often used on the primary digester in a two-stage system. The sludge volume can be varied but only by varying the gas volume at the same time so as to keep the total volume constant. If gas is to be pressurized for use, it must also have a companion floating cover connected by gas lines. Learn More about this product.

Floating Tyoe

Floating Type
Floating covers float directly on the sludge, allowing variable sludge levels. However, practically no gas storage is available and the gas volume is relatively constant. A floating cover provides for submergence of scum and again is often applied on the primary digester in a two-stage system. The floating cover floats on the liquid surface. Learn More about this product.

Gas holders

Gas Holders
Gas Holder covers provide for gas storage by riding on a constant pressure, variable volume gas bubble. Normally this type of cover is used with a constant sludge level and this is the most economical design, and would be applied on a second stage digester. Learn More about this product.

Combination Type

Combination Type
The combination Gas holder cover is a floating cover with a longer skirt, columns, and with the ballast moved from the attic to the skirt bottom and it is a gasholder with a ceiling plate added to the bottom of the truss. Learn More about this product.

Digester Heating Systems

Heat Exchangers

Heat Exchangers
HeatX external heat exchangers are available in either an exchanger-only design or exchanger-boiler combination units which are fully shop assembled and tested with all necessary boiler components including gas, water and electrical controls. . Learn More about this product.


Boilers are provided in 7 sizes, ranging from 270,000 - 2,000,000 BTU/hr, primarily for use in combination boiler / heat exchanger packages. On occasion, they may be used as stand-alone boilers. Fuels used are digester gas with auxiliary natural gas, propane or fuel oil. Learn More about this product.

Combination Boilers and Heat Exchangers

Combination Boilers / Heat Exchangers
Separate, but packaged together, boiler and exchanger design allows an operating boiler temperature range of 180° To 190°F. This provides a high enough boiler temperature to avoid condensation and corrosion that can occur at boiler temperatures of 160°F  or lower. Learn More about this product.

Aerobic Digestion


RollAer aerobic digestion systems provide oxygenation and mixing in aerobic digesters. The RollAer system consists of a large diameter eductor tube submerged below the digester sludge level containing multiple air discharge lines for release of air within the tube. Learn More about this product.