Project Synopsis

Develop a plant water balance followed by a technical and economic process alternatives study to provide recommendations for upgrading/replacing an aging industrial waste water treatment system at a specialty metal alloy manufacturing facility.

Project Summary

PLANT WATER USAGE AND WASTEWATER TREATMENT SYSTEM UPGRADE PROCESS ALTERNATIVES EVALUATION STUDY

The client, a performance alloys manufacturer, requested that Process Engineering Associates, LLC (PROCESS) perform a series of Technical and Economic Process Alternatives Evaluations for improving the performance of the Wastewater Treatment Plant (WWTP) at their metals finishing facility.  The first phase of this effort was to address the existing facility, focusing on the plant’s existing water usage, as well as opportunities for cost saving process improvements.  Alternatives for reducing the water usage, which would consequently reduce the WWTP loading, were to be identified and evaluated.  Subsequently, an evaluation of different WWTP technology alternatives for replacement of the existing facility, which was approaching the end of its useful life, was to be conducted. 

During the first phase, PROCESS performed the following tasks:

  • Development of the baseline information.  A sampling effort was conducted by the client to characterize the current wastewater treatment facility influent and effluent streams.   PROCESS summarized the evaluation information in a design basis.
  • PROCESS used existing plant operating data and input from plant personnel, as well as on-site observations, to generate a water balance for the entire facility.  This balance addressed both normal and peak flow rates for the water streams that were currently being discharged to the WWTP.  PROCESS then reviewed each water user and wastewater generation point in the process and identified technically-feasible processing alternatives for reducing water usage and/or wastewater generation.
  • PROCESS executed technical and economic evaluations of the alternatives for reducing water usage / waste-water generation throughout the plant.  Major areas of investigation included:
    • Process area wash down practices
    • Process water reuse/recycle opportunities.

The technical evaluation addressed the impact of the alternatives relative to factors such as, the effect on WWTP loading, simplicity/flexibility of operation, and maintenance requirements.  The economic evaluation involved performing preliminary capital and incremental operating cost estimates for the alternatives. 

During the following second phase, PROCESS evaluated different WWTP technologies that met the goals of the new WWTP based on a capacity approved by the client after the opportunities for wastewater reduction had been evaluated.  The existing technology in place was a metal hydroxide chemical precipitation operation.  Replacement with this technology was weighed against other available technologies for heavy metals removal. The following tasks were performed:

  • PROCESS surveyed technology alternatives for addressing the client’s WWTP heavy metals removal requirements.  The screening process concentrated on commercially-available technologies.  These included electrocoagulation, membrane filtration, ion exchange, and carbon adsorption.  The technologies were reviewed for this application with attention given to their practicality for the anticipated wastewater loading, expected reliability, maintenance requirements, and relative operating costs.  The quantity and characterization of waste products that would be generated was also considered.
  • PROCESS also explored the option of continued use of metal hydroxide precipitation technology incorporating process improvements (not in the existing system) that would provide better management of process upsets and variability.  This included equalization storage upstream of the chemical treatment that would dampen out the operation, eliminating the need for continuous adjustments of treatment chemical rates, as well as facilitating a more effective sedimentation/clarification step.  In addition, filtration for treated water that would be recycled to the process was added.
  • PROCESS then executed technical and economic evaluations for the technically-feasible process alternatives for a new WWTP which were electrocoagulation and metal hydroxide chemical precipitation.  The technical evaluation included comparison of the alternatives for performance, reliability, maintenance requirements, safety, and flexibility of operation.  The economic evaluation involved performing preliminary capital and operating cost estimates for the alternatives.
  • PROCESS presented and discussed results with the client at the conclusion of the evaluation and provided suggestions for the best alternative for WWTP process options.
  • PROCESS generated a letter report summarizing the findings of the Facility Water Usage and WWTP Process Technical and Economic Alternatives Evaluations.  This report described alternatives identified, the methodology used to evaluate the options, and presented recommendations.

 

Industry Type

  • Specialty Metal Alloy Manufacturing

Utilized Skills

  • WWT plant design
  • Plant water usage minimization opportunity identification
  • Industrial waste water process alternatives evaluation.

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