Case study     MunicipalWastewater
Start Up          October2016
Capacity          200,000m3/d
Location         AnhuiChina

Challenge

Existing biological treatment plant is A/O oxidation ditch process, customer required that the effluent standard should be up from one-class B to one-class A , to solve the problem of COD and NH4-N out of standard.

Solution
One cost-effective solution to achieve nutrient removal  is  the  biological  treament  process. This process employs the benefits of fixed-film systems into the suspended growth activated sludge process. This hybrid process is referred to as Integrated Fixed-film Activated Sludge (IFAS) technology. The IFAS process is typically divided into a series of stages that include anaerobic, anoxic, and aerobic volumes. Within the IFAS process, media is filled in the aerobic stages and retained by stainless steel wedge-wire screens located at the effluent end of the process stage.

Results
The plant operates efficiently since the start up. Due to the low water temperature of 10℃, an almost full development of the biofilm was noticed in less than a month.
The COD average value of the effluent is 60 ~ 65mg/l before oxidation ditch reform, and the NH4-N was 5 ~ 10mg/l, which could not meet the effluent standard of class A.After the transformation, the average effluent COD was below 50mg/l, and the NH4-N was below 2mg/l. After post deep bed denitrification process, the COD average value of effuent   is below 40mg/l, and the total nitrogen is below 10mg/l, it could meets the requirements of class A effluent standard.