Engineering Services / Wastewater Characterization & Treatability Studies
Wastewater Characterization & Treatability Studies
Wastewater characterization & treatability studies are critical steps to figure out if specific treatment method is suitable to treat certain waste stream. Every specification we write starts with a number, not an assumption. Before we talk electrode area or rectifier size, we establish what the stream actually contains and how it behaves under current.
Reviewed for technical accuracy by Janeczka Kowalski, Process / Electrochemical Engineering. Figures and ranges on this page are engineering starting points — verify against your own pilot or vendor data before finalizing a design. The content is created by the Evoaeo engineering team lead by Janeczka, All rights reserved.
Analytical scope
What gets measured before anything else
A characterization package covers COD, TOC, BOD, conductivity, chloride and bromide, pH range across a production cycle, suspended solids, and temperature, plus a target-compound screen when the discharge is expected to contain specific organics, metals, or cyanide. COD is run to Standard Methods 5220, BOD₅ to Standard Methods 5210, and target-compound screening by GC-MS or LC-MS depending on the compound class — keeping analysis on recognized methods matters if the data later has to support a permit application or a regulatory submission, not just an internal design decision.
The BOD:COD ratio from this data set is usually what decides whether electrochemical oxidation runs as the primary organic treatment step or as a polishing stage behind biology. As a rough guide, a ratio above roughly 0.4 tends to favor a biological-primary approach with EO polishing the residual, while a ratio below about 0.2 usually points to EO or another advanced oxidation step carrying the bulk of the load itself — the exact threshold shifts with the specific compounds involved, which is exactly why this is a data-driven decision, not a fixed rule.
Where the stream composition shifts with production schedule — batch chemistry, campaign changeovers, seasonal cooling-water dilution — a single grab sample understates the design problem. We ask for a sampling window long enough to capture that variability before committing to a single design basis.
- COD, TOC, BOD, conductivity, pH range across a full production cycle
- Chloride and bromide, since both drive byproduct chemistry at the electrode
- Suspended solids and oil/grease, which determine pretreatment needs
- Target compound identification by GC-MS or LC-MS where the contaminant isn't already known
- Chain-of-custody sampling protocol matched to the lab performing analysis
Engineering note
A grab sample taken on a slow production day is the single most common source of an oversized or undersized system later. We’d rather push a project two weeks to get a representative composite than build a design basis on one bottle.
Turnaround and decision points
When a second sampling round is worth the delay
Standard analytical turnaround runs 5–10 business days for a full characterization panel, faster for a conductivity/pH/COD screen and slower where target-compound identification needs a specialized lab. We recommend a second sampling round whenever the first data set shows more than roughly 30% variation in COD or conductivity across the collected samples, or whenever a production log shows a campaign changeover fell outside the sampling window — in both cases, a single composite is more likely to represent one operating condition than the plant’s actual range.
A brief worked example: a specialty chemical producer’s first sampling round showed COD ranging from 4,200 to 11,000 mg/L across five grab samples taken over one week, with no clear pattern tied to production schedule. Rather than average that into a single design COD, a second two-week composite sampling program was run aligned to the plant’s actual campaign calendar, which resolved the variation into two distinct COD bands tied to two specific product lines — leading to a treatment-train recommendation sized for the higher band with a bypass consideration for the lower one, rather than a single oversized system built around an averaged number that matched neither actual condition.
Bench-scale trials
Turning a matrix profile into removal data
Once the matrix is characterized, bench trials establish removal kinetics at controlled current density, charge dose, and electrode material — typically run in parallel on BDD and MMO coupons so the electrode decision is made on data rather than a default assumption. Sampling at fixed charge-dose intervals, not fixed time intervals, is what actually produces a usable removal curve, since oxidation is driven by charge passed through the cell rather than elapsed time.
Byproduct screening runs alongside removal tracking on any stream with meaningful chloride or bromide content — chlorate, perchlorate, and AOX get measured in the same bench run, not added later as an afterthought once a removal number looks good.
Application note
On multi-product or campaign-driven facilities, we recommend running the bench trial across at least two production campaigns rather than one, since a removal curve built on a single product’s chemistry can miss how the system performs on the rest of the plant’s output.
Deliverable
What you get out of a treatability study
A treatability report hands over the matrix characterization data, the removal-versus-charge-dose curve for each electrode tested, an energy-consumption estimate at the target removal, a byproduct profile, and a recommendation on treatment-train configuration — EO alone, or EO paired with a specific pretreatment step. That package is what Conceptual & Process Design uses as its starting input, and what a pilot-scale program is built around if the stream justifies one.
- Matrix characterization data with sampling methodology documented
- Removal-vs-charge-dose curves for each electrode material tested
- Byproduct profile: chlorate, perchlorate, AOX where chloride/bromide is present
- Energy consumption estimate at the demonstrated removal target
- Treatment-train recommendation with rationale
Get A Wastewater Characterization & Treatability Study Now
Have a stream ready for characterization? Not sure if your waste stream can be treated efficiently by electrochemical oxidation? No worries, just tell us the parameters of your wastewater, we will run comprehensive analysis, then emit results, it’s free of charge.