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Volume 09 Issue 01
  Volume 10 Issue 3 BHS-Sonthofen Inc. Nov 12, 2019  
     Focus | Featured Article | Technology Application | Innovations | Upcoming Events | Blog 
Turnkey Technology System:  Two BHS Concentrating Candle Filters Followed by the BHS Pressure Plate Filter for final filtration, cake washing and drying
Turnkey Technology System:  Two BHS Concentrating Candle Filters Followed by the BHS Pressure Plate Filter for final filtration, cake washing and drying 

Focus:  Water & Solvent Reuse

Welcome to Year Number 10 of A&SoF.

It’s exciting to look back and reread all the past issues and realize that the insights and examples remain relevant to our industries today.  2019 continues to be a year of growth with several new staff members to strengthen our BHS sales and process teams and including the acquisition of AVA GmbH, for their vertical and horizontal technologies providing turbulent mixing, reacting and drying of wet cakes, powders and process slurries.  The technologies are vacuum or atmospheric, batch and continuous, for final drying to “bone-dry” powders. 

This issue focuses on water and solvent reuse.  We will discuss different examples of liquid reuse in the process industries. 

As always, thanks again, to our readers, for your feedback and if you missed any issues, please click on the following link:  A&SoF to view them.  Have an enjoyable and safe end of 2019.  See you in 1Q 2020.

Barry A. Perlmutter

Featured Article:  Think Differently About Water Conservation:


By Sean Ottewell, Editor at Large

Chemical Processing, September 2019 issue, pages 18-23, 2019.

Water optimization efforts often focus on achieving the highest possible level of recycling. However, many plants also should consider a complementary approach that targets cutting the water use of specific unit operations. When well planned and executed, this can produce substantial savings, as recent projects by BHS-Sonthofen, Suez Water Technologies And Solutions and DuPont Water Solutions show.

Processes that use washing and clarification technologies are ripe for optimization, advises Barry A. Perlmutter, President and Managing Director of BHS-Sonthofen Inc., Charlotte, N.C.

“Processes which use washing technology such as belt filters [Figure 1] can make savings of over 30% in water use by switching to counter-current washing. You can recycle the filtrate with no change in the quality of the washing process,” he says.

Read the full article…

BHS Technology Application:

Pharmaceutical Product Recovery Using BHS Concentrating Candle Filters Downstream of Centrifuges  

Bruce Glines, Senior Process Engineer, BHS-Sonthofen Inc.
Barry A. Perlmutter, BHS-Sonthofen Inc.


In the present process, the pharmaceutical slurry goes to a centrifuge for separation and washing and the cake is discharged as the product.  The centrate of the centrifuge is discharged as a waste material. However, the centrate contains soluble product which is presently lost. The purpose of this project is to recover this material.

The proposed system is to concentrate the soluble material followed by precipitation of the product. The slurry is then further concentrated using a BHS candle filter with the concentrate being introduced back to the process.

After extensive testing with the BHS Pocket Leaf Filter and discussions with the customer, the BHS candle filter was installed.  The unit is producing concentrated slurry of 10% from an initial concentration of 1%. The process was then adjusted to concentrate a 3% slurry to 10% this was easily accomplished by adjusting the filtration timer.  The design of the BHS candle filter followed cGMP guidelines including the qualification documents.

Read more…


BHS Case History:Clean Condensate by BHS Candle Filters

Process Plants International (PPI), an Australian consulting firm that specializes in optimizing, commissioning and maintaining plants in the mining and raw materials processing sector company, recommended BHS-Sonthofen and its candle filters to its Russian customer, Polymetal International (PI), a gold processing plant in Amursk, Russia. 

The sedimentation tanks at the Polymetal gold processing plant were not effectively removing foreign particles, causing increased wear to system components. BHS installed a duplex candle filter skid to keep condensate clean during precious metal extraction.

For more information on the BHS candle filter technology, please visit our website at:


BHS Technical Brief: Separations Under Control  

Barry A. Perlmutter, BHS-Sonthofen Inc.
The Chemical Engineer, September 2019, Issue 939





In the 1970’s, chemical operations that I have been exposed to used acetone and benzene for the main slurry solid-liquid separation process as well as for cleaning. In the 1980’s, there was a push to minimizing solvent use and research was looking more towards using water as the process liquid, but you still had open filter presses, rotary drum filters where the entire plant was “white” from titanium dioxide or pharma stearates. Fast forward to the present and we all know that processes remain open with filter presses, vacuum filters and centrifuges.   Our job these days is to find solid-liquid separation process solutions that can be contained contain for high solids slurries (greater than 10% solids) during filtration, cake washing and dewatering/drying. The discussion in this Tech Brief looks at batch and continuous operations.

Read more…


BHS Technology Paper: Continuum Approach to Optimizing Upstream Filtration with Downstream Drying  

Barry A. Perlmutter, BHS-Sonthofen Inc.

 This article reviews the optimization of the selection of the final drying technology in conjunction with the upstream continuous solid-liquid filtration, cake washing, and dewatering technology selection.  Most often when analyzing a new process development approach, engineers take a “silo” approach and look at each step independently. This article illustrates that by taking a holistic approach and looking at each step not individually but as a continuum, the process solution becomes much more efficient.  

In the manufacturing of this specialty chemical, the crystals coming from the reactor in a methanol slurry must be filtered, washed and dewatered and then dried to a final moisture of less than 1.0 (<1.0 %).  The standard approach would be to first look at the solid-liquid filtration step and optimize this step for the maximum washing and drying efficiency and then with this information optimize the downstream drying.  The operating company, however, took a different approach and looked at the process as a continuum from solid-liquid filtration through cake washing and dewatering to final drying. The Continuum Approach” resulted in operational energy and nitrogen savings as well as lower capital and installation costs for a more efficient and reliable process.

Read more…


What Type of Engineer Are You?

  • There are many different types of engineer. Recently, I read some interesting articles about defining engineers by their skills and depth of knowledge. This blog asks you to consider, what’s your skill shape: I…T…or Key?  ·        
  • I-Shaped Skills reflected a person with a deep (vertical) expertise in one area and practically no experience or knowledge in other areas. ·    
  • T-shaped professional. The vertical bar on the T represents strong knowledge in a specific discipline. The horizontal bar represents a wide yet shallow knowledge in other areas.
  • Key-shaped professional—a person who has several areas of expertise with varying degrees of depth.

Read the blog

Upcoming Events:


a.       Specialty & Custom Chemicals America:  Fort Worth, Texas, 11 -14 February 2019,

b.      AICHE Spring Meeting:  New Orleans, 31 March – 4 April 2019,

c.       Global Petroleum Show:  Calgary, Alberta, Canada, 11 – 13 June 2019,

d.      The Chem Show:  New York City, 22  - 24 October 2019

Copyright © 2019 BHS-Sonthofen, Inc., All rights reserved.
BHS-Sonthofen, Inc.
14300 South Lakes Drive
Charlotte, NC 28273-8794
Phone:  704-845-1190

BHS specializes in thin-cake filtration, washing, and drying technologies for pressure or vacuum, batch or continuous operation for high solids and clarification applications.

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