A global manufacturer of key chemical ingredients used in a wide array of products including clothing, carpeting, automobile thermoplastics, computer cases, and sporting equipment, was planning a facility relocation and expansion that presented a significant wastewater treatment challenge.
At their previous location, the manufacturer was using a perozone system to treat their cyanide-laden wastewater. However, the system as designed could not meet the rigorous discharge standards of the local Publicly Operated Treatment Works (POTW) on the order of 0.04 ppm. Further, they had abandoned the peroxide injection system to reduce the health and safety risks per a companywide mandate.
The expansion required a relocation to a new facility, but the increased production would also triple the company’s wastewater volume. If they did not find an onsite treatment solution, the hauling and disposal costs were going to dramatically increase operating expenses.
Nailing Down the Requirements
Anguil collaborated with the client to understand their specific challenges and determine the project objectives. We gathered benchmark data at the existing facility to identify possible solutions that offer the best return on investment (ROI). Project engineers then worked with the customer to understand their decision-making criteria to evaluate only business viable treatment approaches.
In this case, the client’s priority was to eliminate hauling and disposal costs of their cyanide-laden wastewater. With the expansion at a new facility, they expected their wastewater volume to triple, as well as the corresponding disposal costs. Secondly, they wanted a fully automated system with minimal operator intervention so they could focus on producing products. Third, they wanted to minimize the storage and handling of any noxious chemicals.
Next, water samples were sent to the Anguil lab to validate the different technology considerations. Anguil typically identifies several potential treatment and process options which align with the client objectives, and after presenting these to the customer, collaboratively selects one or several to validate. Anguil proposed several oxidation schemes. The client preferred to move away from ozone and peroxide so alkaline chlorination was selected for this project. It is a well-known method with wide application to similar waste streams and is easily automated.
To validate the treatment process, the customer elected for both a bench trial as well as a scaled pilot. For the bench work, the client provided 5 gallons of wastewater collected from their existing facility. Using the required caustic and bleach treatment protocol and measuring free HCN content via the USEPA Pyridine Barbituric Acid Method (Method 10265), test samples were returned which were below the POTW limit of 0.04 ppm. Based on the bench tests results, chemical dosing requirements and costs were easily established before the system was even installed.
Figure 1 – As received waters from the two (2) drums of HCN wastewater marked 1 and 2 respectively. (Right) HCN wastewater post treatment.
Figure 2 – Example HCN measurements. Non-detect is shown on the right, over range on the left.
After the validation that the method would work, albeit on small sample volumes, the customer requested that Anguil perform a larger pilot study to both validate that larger batch treatments would perform similarly. For the pilot work, the client sent Anguil two (2) fifty-five-gallon drums of wastewater. Adapting an existing pilot system, the same reactions were performed at the previously determined set-points on 15- and 25-gallon batches. Again, final concentrations of HCN were below the required discharge limit. In addition to the further treatment efficacy validation, the chemical dosing requirements were used to estimate yearly operational expenses for the full-scale treatment system as well as size and design the required chemical reagent storage capacity.
Figure 3 – Appx 15 gallons of HCN wastewater before treatment (left) and after treatment (right). Again, the cloudiness is due to the formation of the precipitate.
Putting it all Together
The final step in the process is the system design, realization, and installation. Anguil put together the proposal for a fully automated batch treatment system to handle their expected treatment volumes. The proposal contained specifics on many mechanical components including the tank, pumps and mixer sized as well as the advanced automation and controls – including integration with their existing infrastructure and DCS system – to meet their requirements. Additionally, the appropriate service options for installation, installation supervision, commissioning, and training were included. After the system was installed, Anguil performed a 3-day start-up and training including verification of the system’s ability to treat the wastewater. Anguil’s Aftermarket team will be there to service and support the client as needed.
Anguil’s approach to solving a client’s wastewater problem is to take a wholistic view of the challenge with a series of go/no go steps throughout the process. Project Engineers are always focused on the customer’s business objectives in a collaborative effort to define an efficient and cost-effective trial to validate treatment approaches that align with their objectives. Through the bench and pilot testing, we offer insight gained along with a comparison of pros/cons of the treatment approaches until we get to the treatment system that aligns with the client needs.
As a system integrator with 35+ engineers and 60+ supporting personnel, we take a technology agnostic approach to help our clients get the system they want. In this case, the results from our effort:
- Client walked through a collaborate process to ensure key decision criteria and objectives were met in a timely and cost-effective manner.
- Customer was able to evaluate various oxidation treatment options that aligned with safety and cost parameters.
- Lab and pilot validation trials confirmed treatment approach and provided operational expense estimates to client as requested.
- Anguil provided a single-source system integration approach that included all engineering (Mechanical, Electrical, CAD, Project Engineering) and support services in-house to mitigate exposure to risk and deliver a fully integrated system with install, commissioning, and training support.
- The treatment approach saved the client considerable amount of money versus hauling and disposal services; providing an ROI estimated in the 14-16 month range.
- Anguil’s electrical engineering team developed the automation and controls to automate the batch-treatment process. This results in minimal human interaction and an extremely efficient process. It also proactively notifies them via text and email of system condition, need for chemical reorder, reporting and remote login capabilities.
Note: At the time of bench and pilot testing this wastewater, Anguil was engaged with a second wastewater produced by the client. We followed a similar approach and validated treatment efficacy through lab and pilot studies. The result of onsite treatment for both wastewaters offered the client an incredible cost savings with minimal impact to resources.