Water Online

September 2014

Water Online the Magazine gives Water & Wastewater Engineers and end-users a venue to find project solutions and source valuable product information. We aim to educate the engineering and operations community on important issues and trends.

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BNR 101: Pilot Study wateronline.com ■ Water Online The Magazine 24 I n recent years, single-stage deammonification technology combining partial nitritation and anammox has rapidly become an emerging technology for cost-effective autotrophic nitrogen removal in sidestream centrate. The sidestream has high ammonia concentration, low C:N ratio, and warm temperatures that provide the ideal conditions for anammox bacteria to convert ammonia under anoxic condition (with nitrite) to nitrogen gas. The benefit of this technology in comparison with conventional nitrification/denitrification includes reducing aeration energy, eliminating carbon dependency, reducing alkalinity consumption, and reducing sludge production — all of which have the potential to significantly reduce operational costs for nitrogen removal. At the Metropolitan Sewer Department of Greater Cincinnati (MSDGC), there are more than 200 significant industrial users that discharge industrial wastes into the treatment plant. In order to save energy and operation cost, MSDGC initiated many innovative technologies to treat high- strength wastes more cost-effectively. This paper details the case study of integrating innovative deammonification technology to treat landfill leachate. The regular-strength leachate (old leachate) is characterized by its low ratio of biochemical oxygen demand/chemical oxygen demand (BOD/ COD) and fairly high NH 4 -N (i.e., low biodegradable COD to N ratio). Nitrogen removal from old leachate usually involves autotrophic nitrification and heterotrophic denitrification. There are very few studies reporting the use of a deammonification process to treat landfill leachates, especially in the United States. The objective of this study is to conduct an eight-month pilot project to study the feasibility of nitrogen removal of old leachate using ANITA Mox, a single-stage deammonification process. The outcome of this study is significant because it indicates whether the deammonification process is a viable alternative for treating leachate, and it provides some criteria for full-scale design. In addition, it provides significant understanding of what chemicals would inhibit anammox bacteria and how to optimize its performance. The project also offers valuable information for alternative landfill leachate pretreatment processes. Materials And Methods ANITA Mox grows biofilms on moving carriers in a mixed reactor and can be designed in two configurations — moving bed biofilm reactor (MBBR) and integrated fixed- film activated sludge (IFAS). The biofilm on the MBBR carrier consists of multilayers, where anammox bacteria grow on inner layers and ammonia oxidizing bacteria (AOB) grow on the outer layers to achieve single-step deammonification. In the IFAS configuration, AOB is grown as suspended mixed liquor, where anammox bacteria is the dominant species on the biofilm carriers. Studies of the IFAS system have shown that effectively integrating return sludge that includes AOB will improve single-stage biofilm deammonification process performance due to less mass transfer resistance. The feasibility study consisted of three phases — start-up (May 20 to June 16, 2013), MBBR (June 17 to Aug. 4), and IFAS (Aug. 5 to Oct. 21). As shown in Figure 1, the flow diagram of the bench-scale reactor system, a carbon removal stage (an MBBR reactor with How Does Anammox Technology Perform On Industrial Waste Streams? An innovative, single-stage deammonification technique to treat high-strength waste is tested on landfill leachate. Find out if it makes the grade. By Ting Lu, Biju George, and Hong Zhao Figure 1. Flow diagrams of bench-scale reactor system — MBBR and IFAS phases

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