Biological Phosphorus Removal in Combination with Simultaneous Precipitation

Abstract

Two treatment plants - in the drainage area of Lake Neusiedl in Burgenland (Wulkatal, Eisbachtal)-with nitrification-denitrification and simultaneous precipitation of P were operated with an anoxic -anaerobic aeration tank to obtain biological P-removal. The results indicated that a complete denitrification is essential in the first tank to obtain release and biological uptake of phosphorus. Low loading in the Wulkatal-Plant resulted in incomplete denitrification and a biological P-removal of only 60 %. The dosage of a reduced amount of precipitant indicated a combined action of chemical and biological P-removal. In the Eisbachtal Treatment Plant with the same mode of operation - two aeration tanks of which the first was kept anoxic-anaerobic - a biological P-removal of more than 90 % was obtained under optimal process conditions. At low temperatures the removal efficiency was reduced. This could, however, be compensated by a reduced amount of precipitant. An average addition of about 1 g Fe/gP which is far below the theoretical amount for precipitation resulted in effluent concentrations below 1 mg P/1 over a period of two and half years. At the high loaded Main Treatment Plant of Vienna (F/M ratio about 1 ky/kg.d) which has plug flow conditions in the aeration tanks and ferrous sulfate addition for the control of bulking, a significant biological P-removal has been observed. According to measurements at the 400.000 m3/d plant about 50 % of the P is removed by additional biological uptake.

The Effects of MCRT and Temperature on Enhanced Biological Phosphorus Removal

“…Shapiro et al (1967) reported that anaerobic orthoPsol release rates decreased by 2.1-2.6 times for every 10 0 C temperature decrease in the range 10-30 o C. Boughton et al (1971) found 24-37 0 C to be the optimum range for aerobic orthoPsol uptake. Juni �1978) reported temperature optima for Acinetobacter growth of 34-35 c. Du Pree z et al (1978) cultured Acinetobacter in the temperature range 16-40 0 C and obtained the highest maximum growth rates between 29-35 0 C; maximum growth rates de creased rapidly at higher temperatures and no growth occurred at 41 0 C. Spatzierer et al (1985) observed a decrease of P removal efficiency in a full scale EBPR plant at temperatures below 10 0 C. In the 200 mgd Hyperion, Los Angeles CA plant, EBPR at 1.6 days MCRT was more prone to washout at 23 0 C than at 27 0 C (Shao, 1991). Similarly McClintock et al (1991) reported EBPR washout in pilot-scale EBPR at a 5 day MCRT when the temperature was reduced from 15 to 10 o C. In contrast Sell � � (1981) reported that P removal efficiency was 40% higher at S o C than at 15 0 C. Barnard � � (1985) and Kang � � (1985) reported excellent (90%) P removal at 9 0 C in EBPR plants at Kelowna, Canada and Pontiac, MI. EXPERIMENTAL MATERIALS AND METHODS Two continuous flow activated sludge systems (Table 1), immersed in water baths for temperature control, were operated on settled Richmond CA domestic wastewater supplemented with 50 mg/l acetate (Table 2).…”

Posttreatment of a Brewery Wastewater Using a Sequencing Batch Reactor

“…They state that the maximum aerobic phosphorus uptake typically occurs in the interval between 15 and 20°C. On the other hand, increased phosphorus uptake rates with increased temperatures, in the temperature range of 5 to approximately 30°C, were reported by Shapiro et al (1967), Boughton et al (1971), Spatzierer et al (1985), Mamais and Jenkins (1992), and Brdjanovic et al (1997). Therefore, the relatively high 30°C temperature was not the key factor affecting the efficiency of the biological phosphorus removal process.…”

“…A conventional explanation for such a phenomenon relies on oxygen limitations within microbial flocs. Van Loosdrecht and Heijnen (1993) indicate that oxygen limitation exists in biofilms at depths greater than 100 m. Such environments may provide oxygen-free conditions for heterotrophic denitrifying bacteria activity. However, recent studies indicate that some species perform denitrification even in the presence of oxygen (Lukow andDiekman, 1997, andPatureau et al, 1998).…”

Enhanced biological phosphorus removal

“…In the temperature range from 5°C to around 30°C, increased P-release and/or P-uptake rates with increased temperatures are being reported by Shapiro et al (1967), Boughton et al (1971), Spatzierer et al (1985), Mamais and Jenkins (1992) and Brdjanovic et al (1997). Helmer and Kunst (1997), however, reported a higher specific P-uptake at 5°C than at 10°C.…”