Unravelling riverine microbial communities under wastewater
treatment plant effluent discharge in large urban areas
Received: 21 March 2017 /Revised: 4 June 2017 /Accepted: 9 June 2017 /Published online: 5 July 2017
Springer-Verlag GmbH Germany 2017
Abstract In many highly urbanized areas, effluent from waste-
water treatment plants (WWTPs) represents a significant pro-
portion of the water source for receiving rivers. Microbial com-
munities are major components of riverine ecosystems and me-
diate the processes of nutrients and organic matter produced by
treated and untreated WWTP effluent. To date, the impacts of
WWTP effluent discharge on riverine microbial communities
remain poorly understood. Based on 16S rRNA gene sequenc-
ing and water quality analysis, we investigated the microbial
community compositions and predicted functions in the efflu-
ents of five municipal WWTPs and their receiving rivers. The
results showed that the microbial compositions in the five
WWTP effluents with different treatment processes were simi-
lar. Significant differences in the microbial community were not
noted between the effluent, upstream, and downstream sites for
both sampling months. However, dissimilarity of microbial
composition between two sampling periods was observed.
The temperature, pH, dissolved oxygen, and ammonium were
major environmental factors associated with microbial commu-
nity changes. Functional annotations of microbial communities
based on 16S amplicons identified xenobiotic degradation and
metabolism functions in effluent and river samples.
Quantitative polymerase chain reaction revealed the dominance
of ammonia-oxidizing bacteria (AOB) over ammonia-
oxidizing archaea (AOA) in the WWTP effluents and rivers,
and significant positive correlation between AOB abundance
and nitrate concentration was observed. These findings will
help increase our understanding of the impact of effluent dis-
charge on urban river ecosystems.
Keywords WWTP effluent
Wastewater treatment plants (WWTPs) carry large loads of do-
mestic and industrial wastewater and frequently discharge efflu-
ent into open lotic ecosystems. Despite a series of treatment
processes, WWTP effluent still contains contaminants such as
nutrients and emerging micropollutants (Schwarzenbach et al.
2006). Previous studies have revealed the ecosystem impacts of
WWTP effluent, including increased nutrient loading (Waiser
et al. 2011), eutrophication (Gucker et al. 2006;Pernet-
Coudrier et al. 2012), and community structure disruption of
algae, invertebrates, and fish (Bunzel et al. 2013;Dyeretal.
2003; Spanhoff et al. 2007). These detrimental effects have in-
creased public environmental concern and pose threats to both
riverine and human health. Evaluating and predicting aquatic
responses to WWTP effluent, notably in urbanized watersheds
in arid and semi-arid regions where river flows are perennially
dominated and dependent on WWTP effluent (Brooks et al.
2006), is a continuing challenge.
As the economic and political center of China, Beijing is a
good representative to assess the impacts of WWTP effluent on
receiving river ecosystems. Beijing is one of the fastest growing
Electronic supplementary material The online version of this article
(doi:10.1007/s00253-017-8384-4) contains supplementary material,
which is available to authorized users.
* Jiuhui Qu
Key Laboratory of Drinking Water Science and Technology,
Research Center for Eco-Environmental Sciences, Chinese Academy
of Sciences, Beijing 100085, People’s Republic of China
University of Chinese Academy of Sciences, Beijing 100049, China
Appl Microbiol Biotechnol (2017) 101:6755–6764