Nitrogen removal and ammonia-oxidising bacteria in a vertical flow constructed wetland treating inorganic wastewater

摘要

Nitrogen removal performance and the ammonia-oxidising bacterial (AOB) community werenassessed in the batch loaded 1.3 ha saturated surface vertical flow wetland at CSBP Ltd, a fertilisernand chemical manufacturer located in Kwinana, Western Australia. From September 2008 to Octobern2009 water quality was monitored and sediment samples collected for bacterial analyses. During thenperiod of study the wetland received an average inflow of 1,109 m3/day with NH3-N ¼ 40 mg/L andnNO3-N ¼ 23 mg/L. Effluent NH3-N and NO3-N were on average 31 and 25 mg/L, respectively. Thenoverall NH3-N removal rate for the period was 1.2 g/m2/day indicating the nitrifying capacity of thenwetland. The structure of the AOB community was analysed using group specific primers for thenammonia monooxygenase gene (amoA) by terminal restriction fragment length polymorphism andnby clone libraries to identify key members. The majority of sequences obtained were most similarnto Nitrosomonas sp. while Nitrosospira sp. was less frequent. Another two vertical flow wetlands,n0.8 ha each, were commissioned at CSBP in July 2009, since then the wetland in this study hasnreceived nitrified effluent from these two new cells.