[Environmental Engineering] Joint Design Institute Process Package: Unite Pre-coat Filter Tackles Soda Ash Wastewater Challenges

Project Background:

The soda ash production process (such as the combined or ammonia-soda process) generates complex wastewater containing high salinity, fine suspended solids, and trace organic additives. Because the solid particles in the wastewater are extremely fine and somewhat sticky, traditional sedimentation or ordinary mechanical filtration equipment often fails to achieve ideal clarification and leads to frequent filter clogging. In response to national calls for "Zero Liquid Discharge" and resource recovery, Unite teamed up with a prominent chemical design institute to customize a standardized process package based on "Pre-coat Filtration" for a large-scale soda ash company.

Core Challenges:

• Frequent Filter Clogging: Fine suspended solids in the wastewater (such as calcium carbonate and magnesium hydroxide) easily adsorb onto the filter media, forming a dense cake that causes filtration pressure to rise rapidly.
• High Effluent Precision Requirements: Downstream reuse processes (such as membrane treatment or evaporation crystallization) require extremely clear influent, which traditional filtration methods struggle to provide consistently.
• Process Integration Complexity: Environmental engineering demands not just equipment, but a complete logic chain including filter aid dosing, automated circulation, and sludge dewatering.

Our Solution:

Through joint R&D with the design institute, we created a process package system centered on the "Pre-coat Filter":

• Pre-coat Layer Technology: Before filtration begins, the automated control system applies a pre-coat of filter aid (such as diatomaceous earth, perlite, or cellulose) onto the filter cloth or screen. This "sacrificial layer" protects the main media from direct clogging by sticky materials and provides micron-level interception precision.
• Jointly Designed Process Package: We collaborated with the design institute to optimize hydraulic calculations and piping layouts, deeply integrating the filter aid preparation, precision filtration, and PLC automated control systems into a turnkey process module.
• Automated Backwash & Discharge: The system automatically switches modes based on pressure differential. During backwashing, the pre-coat and intercepted impurities are instantaneously stripped and discharged via an automatic valve, regenerating the filter media without manual cleaning.
• Corrosion-Resistant Selection: Given the high salinity of soda ash wastewater, the entire system utilizes corrosion-resistant stainless steel or anti-corrosive coatings to ensure durability under harsh working conditions.

Customer Value & Results:

Since the commissioning of the pre-coat filtration process package, the effluent suspended solids (SS) have been stably controlled at extremely low levels, fully meeting the influent requirements for downstream membrane systems. Compared to traditional processes, the service life of filter media has been extended several times over, significantly reducing operational consumable costs. With the promotion of the standardized process package by the design institute, this solution has become a model for the environmental upgrading of the soda ash group. Unite has once again demonstrated its comprehensive strength in solving industrial environmental challenges through "Technical R&D + Process Integration."