Project Synopsis

Process engineering and design services for a mixed waste treatment facility treating a variety of mixed, RCRA-hazardous, and TSCA wastes.

Project Summary


The client contracted with Process Engineering Associates, LLC (PROCESS) to provide process engineering services for a process design of a mixed waste treatment facility for treatment of a variety of mixed, RCRA-hazardous, and TSCA wastes.  Specifically, PROCESS was assigned the following project tasks:

  • Task 1 – Perform an extensive assessment of the overall system preliminary process design and planned operation and make design/operation change recommendations as necessary
  • Task 2 – Perform a detailed process evaluation of the direct chemical oxidation system of the facility and make design change recommendations as necessary
  • Task 3 – Execute a process design for the organic recovery area of the direct chemical oxidation system
  • Task 4 – Execute a process control system design for the six major facility processing areas.

Assessment of the overall process primarily involved reviewing preliminary process flow diagrams developed previously by the client and included reviews of the facility mass and energy balance, preliminary unit operation types, sizes, and sequence; and planned facility operation.  This task also included a review of system design and operation relative to compliance with applicable regulatory requirements.  A total of 11 major design/operation changes were recommended for the overall process.  The assessment findings were summarized in a report prepared for the client.

The preliminary design developed by the client for the direct chemical oxidation section of the process included thermal desorption for organic compound recovery, and solvent extraction and liquid-phase chemical oxidation for residual organic removal/destruction.  PROCESS performed an comprehensive review of the preliminary process flow diagram and system material and energy balance, and 3 major design change recommendations were made for the system.  The evaluation findings were summarized in a report prepared for the client.

Commercial process simulation software was used during the design of the direct chemical oxidation organic recovery area to bracket system operation in terms of flow, temperature, pressure, and heat transfer duty.  In addition, the simulation software was used in conjunction with PROCESS’ in-house cost estimating programs to optimize (minimize capital and operating costs) the designs for the recovery area primary (cooling water) condenser, secondary (chilled water) condenser, and desorber vacuum pump.  Furthermore, process simulation was used to technically evaluate the use of direct-contact cooling/condensing for the primary condenser.  The results of the recovery area process design were presented to the client in the form of simulation process flow diagrams and a report summarizing system design recommendations.

Finally, PROCESS executed a control system design including control loops, monitoring points, alarms, and interlocks and prepared detailed process control diagrams (PCDs) for the following major processing areas of the facility: (1) direct chemical oxidation, (2) inorganic wastewater treatment, (3) organic wastewater treatment, (4) reactive waste water treatment, (5) sludge dewatering/conditioning, and (6) chemical feed.  A total of 9 PCDs were prepared.  Finally, a process control description was developed that presented control system philosophy as well as each control point’s functionality and purpose.

Industry Type

  • Hazardous Waste Treatment

Utilized Skills

  • Existing design review and improvement recommendations
  • Computer process simulation
  • Process control systems design

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