For applications within the United States, Enviroquip has coupled its proprietary SymBio® technology for simultaneous nitrification and denitrification (SNdN) with the MBR technology. This combination is proposed for plants designed to meet stringent nutrient removal requirements such as 3-5 ppm TN. Low total nitrogen levels are achieved by using a simultaneous nitrification and denitrification concept in conjunction with the conventional concept of recyle to a pre-anoxic basin from the MBR. Use of SymBio® process results in lower aeration energy consumption for the MBR process and also lowers the internal recycle requirement for denitrification to the anoxic zones.

In a complete BNR plant, the raw equalized influent wastewater is passed through a 1/8” screen first and is then fed into a anoxic tank. HRT in the anoxic basin is based on the plant or the influent loading, the operating temperature, and the nitrogen removal requirements for the plant. From the anoxic tank, the wastewater is usually pumped to the membrane bioreactor (MBR). In cases where the influent loading is high, a pre-aeration basin is recommended before the MBR in order to provide additional biological treatment. In this case, wastewater is pumped from the anoxic basin to the pre-aeration basin and is fed from the pre-aeration basin to the MBR by gravity. The mixed liquor is recycled back to the anoxic basin from the MBR by gravity to complete the recycle loop. The pre-aeration basin is usually maintained at low dissolved oxygen (DO) levels below 1.0 mg/L for simultaneous nitrification and denitrification (utilizing Enviroquip’s SymBio® Process). The MBR is maintained under aerobic conditions at DO > 1 mg/L.

Running Springs Case Study:
Existing 0.6 MGD Conventional activated sludge plant was converted to a 1.0 MGD Membrane Bioreactor plant. Running Springs is the first full scale MBR plant with EBPR (Enhanced Biological Phosphorus removal) and SymBio® for (SNdN).

Jacksonville, Florida Case Study:
Existing 0.3 MGD Nassau regional WWTF needed to be upgraded to 3.0 MGD to meet the high growth in the region. The Jacksonville Electric Authority (JEA) selected Enviroquip MBR due to its high quality treatment accompanied with SymBio®, ease of operation and small footprint.