Removing Surfactants to Decrease Discharge Costs
Process innovation · Capital savings
Foaming that threatened the discharge permit.
The wastewater generated by an industrial client was causing problems at the publicly owned treatment works (POTW) where it was being discharged. A high concentration of surfactants and other organic chemicals caused intensive foaming in the pump stations and plugged the air relief valves in the force main.
The client faced a ban on discharging to the POTW unless it could pretreat the water to remove the surfactants, chemical oxygen demand (COD), and suspended solids.
Skip the $3.8M plant — change the chemistry.
The client first determined that dissolved air flotation clarification could remove suspended solids and some COD and surfactants. Their pilot study showed the process might work, but it would be plagued with housekeeping, reliability, and maintenance issues — and carried a capital estimate of$3.8 million.
Recognizing the impracticality of that conventional route, Mr. McKinnon researched and identified an alternative. His proposal used a proprietary adsorbent/polymer product to adsorb the surfactants and remove their foaming tendency, modifying the wastewater so the pretreated effluent could go to the client’s own treatment plant. The client could then remove solids in their primary clarifier and dewater them with their other sludge — and stop discharging to the POTW altogether.
A fraction of the original price tag.
Following a trial that verified the effectiveness of Mr. McKinnon’s proposal, the client constructed the new system and disconnected from the POTW.
The alternative process cost $1.5 million — a capital savings of $2.3 million compared to the initial plan.