Szilágyi, N.1,2, Kovács, R.1, Kenyeres, I.1, Csikor, Zs.2
1Organica Technologies, Hungary,
2 Budapest University of Technology and Economics, Hungary
Modern society is rapidly placing new demands on the wastewater treatment field, which has changed little in the past several decades; included in these new demands is reducing footprint and operational costs while increasing treatment efficiency. The technologies which suit these requirements best are biofilm-based. In this paper a biofilm-based system is introduced based on experiments conducted within a full-scale industrial plant treating the wastewater of a cheese factory in Hungary. The results showed excellent performance; the technology provided 94.7% COD removal efficiency and 96.6% ammonia-N removal efficiency during the 118-day monitoring campaign. Additionally, the total beneficial biomass quantity in the reactors was much higher compared to conventional technologies; a biomass amount of 15-20 kg/m3 was observed.
Introduction
In the field of industrial wastewater treatment, anaerobic technologies are the most widely used since these are more suitable for treating high organic matter loading rates. In general aerobic systems are suitable for biodegradable COD concentrations lower than 1000 mg/l (Chan et al. (2009)). However according to Cakir and Stenstrom (2005) there is a range in influent BOD5 concentration where anaerobic and aerobic technologies are both suitable.
In considering both aerobic and anaerobic treatment technologies, an increasing trend of biofilm-based technologies is emerging. Biofilm-based systems have several advantages such as smaller footprint, better process stability, enhanced sludge settleability, and in addition, reduced solids loading on the secondary clarifier (Tchobanoglous et al, 2004). Moreover, in biofilm-based technologies a significantly higher observable sludge residence time (SRT) can be achieved compared to conventional treatment technologies such as activated sludge systems (AS) (Shieh et al. 1981).
In this paper an aerobic biofilm-based wastewater treatment technology is introduced founded on the operational experiences observed in a full-scale industrial plant. The examined technology consists of aerobic reactors in series filled with biofilm carriers. The general components of the reactors can be seen in Fig. 1. Plants are placed on the top of each reactor (1 – numbers are according to Fig. 1) with their roots (2) extending under the water level.
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