Dilution Tanks and Traps

A dilution tank simply mixes corrosive discharge with additional water to reduce concentration before sewer discharge. A neutralization tank goes further, using a buffering media (such as limestone chips) or an active chemical feed system to actually adjust pH toward neutral, which is typically required when dilution alone can't reliably bring effluent within the local sewer ordinance's discharge limits.

Size to peak simultaneous discharge volume, not average daily flow — if multiple lab sinks or process drains can discharge into the system at the same time, the tank needs enough capacity and retention time to fully dilute that peak event before it passes through. Undersizing is a common compliance failure point.

No — standard polyethylene has good general resistance to many acids and bases but is not universally chemical-compatible, and certain solvents and strong oxidizers can degrade it over time. Always check a chemical compatibility chart against your actual waste stream, or specify fiberglass or PVC-lined construction where compatibility is uncertain.

Many local sewer discharge ordinances require documented pH compliance, which effectively requires monitoring equipment (continuous or periodic sampling) rather than assuming the dilution ratio alone guarantees compliance. Check your specific municipal or industrial pretreatment discharge permit requirements.

Above-ground tanks are easier to inspect, maintain and monitor, and are common for lab and light industrial settings with available floor space. Buried tanks save space and suit larger facility installations but require structural load rating if sited under vehicle traffic, and are harder to inspect and service — the choice usually comes down to available space and maintenance access requirements.