THE KOI PROCESS

The KOI Environmental RTF consists of a bed of highly permeable plastic media in a randomly packed configuration to which microorganisms are attatched and through which wastewater is percolated.

The wastewater is passed from the primary settling tank, where a portion of the solids are separated from the untreated wastewater, to a sump in the KOI unit where further settling occurs. A dosing pump then doses the trickling filter unit.

In the trickling filter unit, the organic material present in the wastewater is degraded by a population of microorganisms attached to the filter media. Organic material from the liquid is absorbed onto the biological film or slime layer. In the outer portions of the biological slime layer, the organic material is degraded by aerobic microorganisms. As the microorganisms grow, the thickness of the slime layer increases and the diffused oxygen is consumed before it can penetrate the full depth of the slime layer. Thus an anaerobic environment is established near the surface of the media.

As the slime layer increases in thickness, the absorbed organic matter is metabolized before it can reach the microorganisms near the media face. As a result of having no external organic source available for cell carbon, the microorganisms near the media face enter into an endogenous phase of growth and lose their ability to cling to the media surface. The liquid then washes the slime off the media and a new slime layer starts to grow. This process is called sloughing and is primarily a function of the organic and hydraulic loading on the filter. The hydraulic loading accounts for sheer velocities and the rate of metabolism in the slime area.

The sloughed biomass settles to the bottom of the sump as sludge and is periodically pumped back into the primary tank before final disposal by a pump truck. A forced draft ventilation system provides adequate air flow and a variable irrigation rate provides flexibility and control over removal efficiencies.

On-line Tech Support

Large flow KOI Environmental Inc. recirculating trickling filters have interactive computerized control panels for remote monitoring, datalogging, alarm and operating functions. System information is monitored continuously and stored for reference. Should the system operator require assistance, KOI personnel can contact the system directly, evaluate the system operational inputs (flow, temperature, dissolved oxygen, pH, etc.) and make adjustments to the system anywhere in the world that has telephone service.

Smaller flow systems are connected to a centralized monitoring system for alarm functions.