Ammonia-Oxidizing Bacteria and Archaea in Groundwater Treatment and Drinking Water Distribution Systems

Abstract

The ammonia-oxidizing prokaryote (AOP) community in three groundwater treatment plants and connected distribution systems was analyzed by quantitative real-time PCR and sequence analysis targeting the amoA gene of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Results demonstrated that AOB and AOA numbers increased during biological filtration of ammonia-rich anoxic groundwater, and AOP were responsible for ammonium removal during treatment. In one of the treatment trains at plant C, ammonia removal correlated significantly with AOA numbers but not with AOB numbers. Thus, AOA were responsible for ammonia removal in water treatment at one of the studied plants. Furthermore, an observed negative correlation between the dissolved organic carbon (DOC) concentration in the water and AOA numbers suggests that high DOC levels might reduce growth of AOA. AOP entered the distribution system in numbers ranging from 1.5 ؋ 10 3 to 6.5 ؋ 10 4 AOPs ml ؊1 . These numbers did not change during transport in the distribution system despite the absence of a disinfectant residual. Thus, inactive AOP biomass does not seem to be degraded by heterotrophic microorganisms in the distribution system. We conclude from our results that AOA can be commonly present in distribution systems and groundwater treatment, where they can be responsible for the removal of ammonia.Ammonia can be present in source water used for drinking water production or added to treated water with chlorine to form chloramines as a disinfectant. However, the presence of ammonia in drinking water is undesirable because nitrification might lead to toxic levels of nitrite (29) or adverse effects on water taste and odor (4) and might increase heterotrophic bacteria, including opportunistic pathogens (29). Two-thirds of the drinking water in The Netherlands is produced from groundwater. Most of the groundwater used for drinking water production is anoxic with relatively high concentrations of methane, iron, manganese, dissolved organic carbon (DOC), and ammonia. Treatment of anoxic groundwater aims at achieving biologically stable water, because drinking water in The Netherlands is distributed without a disinfectant residual. As a result, a highly efficient nitrification process during rapid medium filtration is required.Nitrification is the microbial oxidation of ammonia to nitrate and consists of two processes: the oxidation of ammonia to nitrite by ammonia-oxidizing prokaryotes (AOP) and the oxidation of nitrite to nitrate by nitrite-oxidizing bacteria (NOB). Recently it was shown that in addition to bacteria, archaea also are capable of ammonia oxidation (13). Since then, ammoniaoxidizing archaea (AOA) have been found in many different ecosystems, including wastewater treatment systems (10,20,24). However, it is currently unknown if AOA are present in drinking water treatment processes and distribution systems. Recent studies have focused on nitrification in drinking water treatment (16,28). In those studies, AOB and NOB were enumerated by traditional most-proba...

Ammonium Availability Affects the Ratio of Ammonia-Oxidizing Bacteria to Ammonia-Oxidizing Archaea in Simulated Creek Ecosystems

“…S4 in the supplemental material). Here, sequences formed a cluster together with sequences obtained from groundwater (32) and from a drinking water distribution system (41), which may point to a special affiliation of this group with freshwater environments. However, we did not detect novel AOA AmoA clusters that would indicate the existence of special creek-associated AOA.…”

“…Here, nitrification as the first step in coupled nitrification-denitrification is a key step in the removal of the allochthonous nitrogen load, preventing the eutrophication of downstream ecosystems (1,5,29,39). The activity and community composition of biofilm-associated nitrifying microorganisms have been investigated extensively in wastewater treatment systems (27,36), in drinking water distribution systems (17,41), and in lakes, large rivers, and estuaries (7,19,21,39) but only rarely in small-creek ecosystems. The first and ratelimiting step in nitrification, oxidation of ammonia, is carried out by ammonia-oxidizing archaea (AOA) (14) and ammoniaoxidizing bacteria (AOB) (16).…”

Seasonal Changes of Freshwater Ammonia-Oxidizing Archaeal Assemblages and Nitrogen Species in Oligotrophic Alpine Lakes

“…4). Indeed, the closest relatives in GenBank for most of the recovered amoA sequences were obtained from rhizosphere, groundwater, and drinking waters (33,57,66) (Table 3).…”

Seasonal Change in Vertical Distribution of Ammonia-Oxidizing Archaea and Bacteria and Their Nitrification in Temperate Forest Soil

“…3). Marine Cluster-1 included 8 OTUs that were related to amoA clones obtained previously from a drinking water treatment plant (47). Clones FS_G37799 and FS_G37677 within Marine Cluster-1 occurred at a relatively high frequency (10% to 14%) in July and in microcosms ( Table 2).…”