Nitrogen removal in attached growth waste stabilization ponds of wastewater from a rubber factory

Abstract

Nitrogen removal from wastewater from rubber factories using attached-growth waste stabilization ponds (AGWSP) was evaluated. Usually, wastewaters generated from rubber factories such as concentrated latex factories and rubber sheet factories contain a high amount of nitrogen originating from natural rubber and ammonia compounds added in the production processes. From an investigation of 3 rubber factories at Songkhla, Thailand, average concentrations of TKN, NH 3 -N and Org-N in raw factory wastewater were found to be 889, 578 and 311 mg/l respectively. Two series of laboratory waste treatment ponds, waste stabilization ponds (WSP) and attached-growth waste stabilization ponds were investigated to compare the efficiency of nitrogen removal from wastewater from a concentrated latex factory. The wastewater fed to the experimental units was collected from the effluent of the anaerobic treatment pond at the factory. The experiments were conducted with hydraulic retention times (HRT) of 40 and 20 days. Another experiment run with an HRT of 40 days together with 50% recirculating of effluent was also conducted. Finally, an experiment run at an HRT of 4 days was carried out in order to observe the effect of shock loading. The results revealed that TKN, NH 3 -N and BOD 5 removal efficiencies in AGWSP were higher than in control ponds (WSP). Increased removal efficiencies were achieved which resulted from an increase in biomass on media in the pond water.