Application of Integrated Fixed-Film Activated Sludge in a Conventional Wastewater Treatment Plant

Abstract

It is often only at the operation stage of a wastewater treatment plant that there is a need to adjust the treatment process in terms of variable hydraulic capacity, increased pollutant load, high/low concentration of suspended biomass, or the unfavorable phenomenon of reduced sedimentation capacity of the activated sludge. One of the ways to improve the treatment process efficiency is to increase the biologically active surface by using bio-carriers in the form of fibers, materials, or bio-balls. This paper presents the results of a wastewater treatment plant operation during the period of six months after the implementation of the integrated fixed-film activated sludge (IFAS) technology. The research showed that microorganisms developed both in the activated sludge and on the fibers, positively influencing the activated sludge condition. During the start-up of the IFAS process, ciliates predominated over the other species. However, as oxygen content was high (2 mg/dm3 and more) and textile beds were used, the protozoan population developed intensively, and small metazoans became increasingly common. Throughout the research period, nitrifying and phosphorus-accumulating bacteria were observed both in the activated sludge and on the fibers. Between the 59th and 184th day of operation, numerous microorganisms were detected on the fibers and in the activated sludge, testifying to low biological oxygen demand, good aerobic conditions for nitrification, and long sludge age. However, the process seemed to break down after day 72, when the occurrence of metazoan led to reduced sludge production; after day 88, chemical oxygen demand and total suspended solids in the outflow increased, and oligochaetes and rotifers dominated the suspended sludge and fibers. Results also showed that the textile bed and low ammonia concentration became an excellent substrate for the development of Stentor sp. With regard to chemical and biological oxygen demand, total nitrogen- and total phosphorus-effluent concentrations were mostly within the legally permissible limits throughout the 184 days of operation.

Assessment of Chemical Oxygen Demand Removal Efficiency and Microbial Dynamics during Aerobically Degradation of Wastewater in Activated Sludge

“…While bacterial flocs were consistently present throughout the experiment, flagellates, free-swimming ciliates, stalked ciliates, and rotifers proliferated from absent or negligible initially to abundant populations by day 12. These results as shown in Figure 7 agree with previous observations that protozoa and metazoa become increasingly predominant over time in activated sludge systems (Araújo dos Santos et al, 2014;Bitton, 2005;Kuśnierz et al, 2022). According to (Madoni, 2011), protozoan grazer populations progressively rise toward climax communities in mature activated sludge.…”

Seasonal prevalence of bacteria in the outflow of two full-scale municipal wastewater treatment plants

“…2 ). The increase in beta AOB at the outflow in the summer for A-WWTP was probably due to the implemented new technology, where technological problems were observed during this period 37 . The composition of activated sludge fed with municipal wastewater is usually dominated by Proteobacteria, with Betaprotebacteria being the dominant class 15 .…”

Effective mechanisms of water purification for nitrogen-modified attapulgite, volcanic rock, and combined exogenous microorganisms

“…The exogenous microorganisms, included Bacillus licheniformis, Bacillus sp. (Jiangsu Suwei microbial research Co., Ltd.) (Ren et al, 2021), and activated sludge (Sk Hynix Semiconductor (Wuxi) Co., Ltd.) (Santorio et al, 2021;Kuśnierz et al, 2022), were named as three bacteria liquids. Their concentrations were 10.3389/fmicb.2022.944366 1 × 10 8 -1 × 10 9 CFU/ml of a bacterial liquid dosage of 1 mg/L following Murray et al (1981).…”

“…The exogenous microorganisms were used to enhance the water purification effect when combined with purification materials that can provide a microorganism-loaded environment ( Ren et al, 2021 ; Yin et al, 2022 ). The nitrifying and phosphorus-accumulating bacteria were enriched when added microorganisms in the activated sludge ( Kuśnierz et al, 2022 ).…”