Wastewater from the building is gravity fed into the first chamber (Suboxic Chamber). In the ?rst chamber, settling of the sludge and solids occurs. The primary clarified wastewater overflows into the second chamber (First Aeration). In the second chamber the wastewater is aerated using a high efficiency low-pressure linear air blower and membrane air diffuser assemblies. The diffuser assemblies are custom designed to ensure maximum oxygen transfer and optimum mixing of dissolved substrates and oxygen. Furthermore, the mixing ensures that the solids remain suspended within the reactor and that the biomedia does not clog. The aeration promotes growth of aerobic microorganisms, which convert and remove biodegradable organic matter. (The organics removed by the aerobic process are the constituents that are measured in the BOD5 test.)
The treated wastewater, which is now low in carbon but high in ammonia, gravity flows into the third chamber (Aeration #2). This chamber is aerated in the same way as the first aeration chamber. The oxygen rich atmosphere in this chamber promotes the growth of nitrifying microorganisms (Nitrosomonas and Nitrobacter), since it is low in carbon and high in ammonia. The nitrifying microorganisms convert ammonia to nitrates utilizing the oxygen in the wastewater.
To optimize the contact time and the mean cell residence time, the Envirocycle® unit utilizes biomedia in the aerated sections. This media is used to supply a support structure for the establishment of a resident biofilm and is specifically developed for optimized biological growth without clogging. This will favor the nitrification process, which is significantly slower than the organic removal. The biomedia also works as a mixer, which together with the air flow creates optimum mixing of bacteria and wastewater.
The two-stage aerobically treated wastewater, which is now high in nitrates but low in carbon (low in BOD) flows into the fourth chamber (Clarification), where final clarification and settling of the suspended solids take place.
To promote denitrification, and to remove the accumulated biomass, the wastewater is recirculated by a lift tube from the fourth chamber back to the first chamber. The lift system does not have any moving parts. A volume equal to four percent of the system’s rated capacity is recirculated each hour. Denitrification is facilitated by this recirculation because the bacteria in the first suboxic chamber use the oxygen from the nitrate molecule in their metabolic process, with nitrogen being released as gas in the reaction. Without recirculation, the small amount of carbon available in the fourth chamber would limit the denitrification.
The recirculation of the biomass prevents accumulation of biomass in the Clarifier, eliminating the need for periodic removal. Moving the accumulated biomass also helps to ensure optimum clarifier performance resulting in an effluent with low suspended solids. The transfer of the biomass to the first chamber ensures a large vital population of microorganisms for the organic and nitrogen removal processes.
The recirculation process also benefits the system in times of low loading such as vacation periods. When the mass is recirculated, it carries nutrients from the first compartment into the second compartment. The available nutrients are utilized to sustain the population as long as possible. In normal operation this keeps sludge build up to a minimum by helping to break up and dissolve the solids, making the nutrients available for the microorganisms.
The Suboxic Chamber is sized to hold any non-degradable solids for up to 20 years depending on the usage of the system.
The Envirocycle® unit is equipped with an alarm & control panel which has local audible and visual alarms for alerting to high water level, low air, as well as proper function of other components critical to the treatment process. The alarm panel is built into the Envirocycle® unit and features battery backup and a display that continuously updates the unit status. The alarm panel also features wireless remote monitoring and control that allows Envirocycle® Certified Resellers-Installers to receive alarm notices by text message or e-mail and respond remotely over the Internet to trouble shoot and correct the system malfunction. The EnviroSentryTM control panel keeps the Envirocycle® unit operating at peak performance with virtually no owner involvement necessary.