Afaf Abdel Razik Mohamed, Ali El-Dissouky Ali, Mohamed Salah El-Din Hassouna et al.

Applied Water Science • 2025

Abstract Ammonia presence in water has many negative impacts including eutrophication. So, the major objective of this research was to evaluate the efficiency of microbial fuel cell (MFC) and electrochemical (ECS) systems for their removal and/or recovery from wastewater at different levels of ammonia (500 ppm, 1000 ppm, and 1500 ppm). Additionally, a novel approach was tested by using nanomaterial prepared from pomegranate peel as a coating material for the electrodes as it is abundant in many countries. Two systems were tested: Group (A) with a non-coated graphite plate anode (MFC1 and ECS1) and Group (B) which was coated with nano-graphene oxide made from pomegranate peels (MFC2 and ECS2). Results revealed that MFC1 gave the best ammonia removal efficiency reaching 96.2% when the initial concentration was 500 ppm after 13 days, and MFC2 gave maximum removal efficiency of 94.4% and 99.4% for 1000 and 1500 ppm after 19 and 25 days, respectively. COD results coincided with the removal efficiency. Electrochemical ammonia removal was carried out using two external electrical currents, 40 and 80 mA. Results showed that ECS2 gave the highest ammonia removal efficiency of 95.08% at 80 mA in case of 500 ppm, and the maximum for recovery was 80% when 1000 ppm was tested at 80 mA along with an increase in pH in the cathode chamber. Furthermore, ECS2 consumed less energy than ECS1 for ammonia recovery. ECS2 efficiently treated slaughterhouse wastewater reaching almost 100% ammonia removal; however, the maximum recovery of 44.7% occurred after 6 h, but consuming less energy than ECS1. It was evidenced that using an anode coated with nanographene oxide provided dual benefits of quickness and effective ammonia removal and/or recovery and provisioning energy requirements.

Efthalia Chatzisymeon

Water • 2021

Existing wastewater treatment plants (WWTPs) face huge challenges that can impede the achievement of sustainable development goals for clean water and sanitation (SDG 6) and clean energy (SDG 7), amongst others [...]

Cristina Quintelas, Daniela Mesquita, Eugénio Campos Ferreira

Biological Treatment of Industrial Wastewater • 2021

The discharge of industrial wastewater into the environment is an issue of particular concern especially in developing countries. In some cases, these industrial wastewater effluents are untreated or inadequately treated before being discharged and represent a threat to the environment and human health. This chapter highlights the scientific literature published in the last decade on issues related to the discharge of polluted industrial wastewater, including a review of general environmental pollutants, both chemical and microbial, as well as the ecological implications of industrial wastewater discharge for the environment, in water, soil and air ecosystems. Finally, the health impacts of these pollutants is summarized. The authors are aware that regular monitoring and appropriate legislation is necessary to avoid or minimize this problem and, in this context, the challenges and future perspectives related to the discharge of industrial wastewaters are presented.

Komal Agrawal, Pradeep Verma

Biological Treatment of Industrial Wastewater • 2021

The membrane bioreactor system due to its advantages such as improved effluent quality, disinfection, better nitrification, smaller footprint and production of sludge has paved its way in the treatment of wastewater over conventional purification methods. This technology has been effective in removing organic, inorganic and microorganisms from both municipal and certain industrial wastewater systems. In the membrane bioreactor system, the membrane system allows physical separation whereas the bioreactor enables the biodegradation of the pollutant. There are various types of bioreactors, such as the plug-flow reactor, sequencing batch reactor, upflow anaerobic sludge blanket etc. Various parameters such as hydrodynamic conditions, biomass concentration, pH and temperature affect the pollutant removal potential of the bioreactor. Thus, the present chapter deals with process description and configuration, the effect of MBRs on microorganisms, the quality of water after treatment along with the cost associated with MBR technology. The limitations, advantages and technological advances are also elaborated in the chapter.

Rajneesh Kumar, Gurvinder Kaur Saini, Mohammad Jawed

Biological Treatment of Industrial Wastewater • 2021

Industrial wastewater varies in quality and quantity depending on the industry type and may contain various toxic compounds. In a biological process, organic substances in the wastewater are used as food by bacteria and other microorganisms. Several biological reactors conventionally used for industrial wastewater treatment are briefly discussed in this chapter. Biological reactors are categorized as aerobic, anaerobic, and a combination of both based on their oxygen requirement. The suspended and attached growth processes are a further subdivision of aerobic and anaerobic processes. Advanced biological reactors such as membrane bioreactors and granular sludge technologies are primarily used in industry. Industrial wastewater contains various organic and inorganic pollutants. The occurrence of toxic compounds imparts toxic or inhibitory effects on microorganisms and may lead to failure of the biological units. Thus, the impact of several industrial wastewaters on various biological reactors are also discussed in this chapter.

Cecilia Oluseyi Osunmakinde, R. Selvarajan, B. Mamba et al.

Microorganisms • 2019

Next-generation sequencing provides new insights into the diversity and structure of bacterial communities, as well as the fate of pathogens in wastewater treatment systems. In this study, the bacterial community structure and the presence of pathogenic bacteria in three wastewater treatment plants across Gauteng province in South Africa were studied. The physicochemical results indicated that the quality of wastewater varies considerably from one plant to the others. Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi were the dominant phyla across the three wastewater treatment plants, while Alphaproteobacteria, Actinobacteria, Bacilli, and Clostridia were the dominant classes. The dominant bacterial functions were highly associated with carbohydrate, energy, and amino acid metabolism. In addition, potential pathogenic bacterial members identified from the influent/effluent samples included Roseomonas, Bacillus, Pseudomonas, Clostridium, Mycobacterium, Methylobacterium, and Aeromonas. The results of linear discriminant analysis (LDA) effect size analysis also confirmed that these bacterial pathogens were significantly abundant in the wastewater treatment systems. Further, the results of this study highlighted that the presence of bacterial pathogens in treated effluent pose a potential contamination risk, transmitted through soil, agriculture, water, or sediments. There is thus a need for continuous monitoring of potential pathogens in wastewater treatment plants (WWTPs) in order to minimize public health risk.

Hamed Gholami Derami, Qisheng Jiang, Deoukchen Ghim et al.

ACS Applied Nano Materials • 2019

Toxic heavy metal ions and organic pollutants are significant concerns in wastewater treatment. Here, we demonstrate a novel membrane composed of polydopamine (PDA) particles and bacterial nanocellulose (BNC), which can efficiently remove a variety of metal ions and organic dyes from contaminated water. The biocompatible and biodegradable PDA/BNC membrane is synthesized by in situ incorporation of PDA particles into BNC matrix during its bacteria-mediated growth. We show that the PDA/BNC membrane can effectively remove heavy metal ions such as lead and cadmium, and organic dyes as surrogate markers of organic pollutants such as rhodamine 6G (R6G), methylene blue (MB), and methyl orange (MO). The removal efficiencies of contaminants were tested separately or simultaneously via simple filtration at pH values ranging from 4 to 7. Furthermore, after simple washing with regeneration agents, the membrane can be reused multiple times without compromising its contaminant sorption ability and mechanical integrity....

Lin Shi, Naiyuan Liu, Gang Liu et al.

Microorganisms • 2021

Chemicals of emerging concern (CEC) in pig farm breeding wastewater, such as antibiotics, will soon pose a serious threat to public health. It is therefore essential to consider improving the treatment efficiency of piggery wastewater in terms of microorganisms. In order to optimize the overall piggery wastewater treatment system from the perspective of the bacterial community structure and its response to environmental factors, five samples were randomly taken from each area of a piggery’s wastewater treatment system using a random sampling method. The bacterial communities’ composition and their correlation with wastewater quality were then analyzed using Illumina MiSeq high-throughput sequencing. The results showed that the bacterial community composition of each treatment unit was similar. However, differences in abundance were significant, and the bacterial community structure gradually changed with the process. Proteobacteria showed more adaptability to an anaerobic environment than Firmicutes, and the abundance of Tissierella in anaerobic zones was low. The abundance of Clostridial (39.02%) and Bacteroides (20.6%) in the inlet was significantly higher than it was in the aerobic zone and the anoxic zone (p < 0.05). Rhodocyclaceae is a key functional microbial group in a wastewater treatment system, and it is a dominant microbial group in activated sludge. Redundancy analysis (RDA) showed that chemical oxygen demand (COD) had the greatest impact on bacterial community structure. Total phosphorus (TP), total nitrogen (TN), PH and COD contents were significantly negatively correlated with Sphingobacteriia, Betaproteobacteria and Gammaproteobacteria, and significantly positively correlated with Bacteroidia and Clostridia. These results offer basic data and theoretical support for optimizing livestock wastewater treatment systems using bacterial community structures.

F. Qi, Y. Jia, R. Mu et al.

Scientific Reports • 2021

Microalgal-bacterial consortium is an effective way to meet increasingly stringent standards in wastewater treatment. However, the mechanism of wastewater removal effect has not been properly explained in community structure by phycosphere. And little is known about that the concept of macroecology was introduced into phycosphere to explain the phenomenon. In the study, the algal–bacterial consortia with different ratios of algae and sludge were cultured in same aerobic wastewater within 48 h in photobioreactors (PSBRs). Community structure at start and end was texted by metagenomic analysis. Bray–Curtis similarities analysis based on microbial community showed that there was obvious convergent succession in all consortia, which is well known as “convergence” in macroecology. The result showed that Bray–Curtis similarities at End (overall above 0.88) were higher than these at Start (almost less than 0.66). In terms of community structure, the consortium with 5:1 ratio at Start are the more similar with the consortia at End by which the maximum removal of total dissolved nitrogen (TDN, 73.69%), total dissolved phosphorus (TDP, 94.40%) and NH3-N (93.26%) in wastewater treatment process and biomass production (98.2%) higher than other consortia, according with climax community in macroecology with the highest resource utilization than other communities. Therefore, the macroecology can be introduced into phycosphere to explain the consortium for advanced wastewater treatment and optimization community structure. And the study revealed a novel insight into treatment effect and community structure of algal–bacterial consortia for advanced wastewater treatment, a new idea for to shortening the culture time of consortium and optimize predicting their ecological community structure and predicting ecological community.

Aditi Sharma, Upasana Bhardwaj, Devendra Jain et al.

ACS Omega • 2022

In the present work, ferroelectric sodium niobate (NaNbO3) nanorods are formulated to attain photopiezocatalysis for water pollutant degradation and bacterial disinfection. NaNbO3 nanorods, integrating the advantages of photocatalysis (generation of free charge carriers) and piezocatalysis (separation of these charge carriers), possess synergistic effects, which results in a higher catalytic activity than photocatalysis and piezocatalysis alone. Active species that are involved in the catalytic process are found to be •O2– < OH• < h+, indicating the significance of piezocatalysis and photocatalysis. The degradation efficiency of sodium niobate (NaNbO3) nanorods for Rhodamine B in the presence of both sunlight and ultrasonic vibration is 98.9% within 60 min (k = 7.6 × 10–2 min–1). The piezo potential generated by NaNbO3 nanorods was reported to be 16 V. The antibacterial activity of the produced sample was found to be effective against Escherichia coli. With inhibitory zones of 23 mm, sodium niobate has a greater antibacterial activity.

L. Senila, Alexandra Hoaghia, A. Moldovan et al.

Materials • 2022

The aim of this study was to investigate the use of natural zeolite as support for microbial community formation during wastewater treatment. Scanning electron microscopy (SEM), thermal decomposition and differential thermogravimetric curves (TGA/DGT) techniques were used for the physicochemical and structural characterization of zeolites. The chemical characterization of wastewater was performed before and after treatment, after 30 days of using stationary zeolite as support. The chemical composition of wastewater was evaluated in terms of the products of nitrification/denitrification processes. The greatest ammonium (NH4+) adsorption was obtained for wastewater contaminated with different concentrations of ammonium, nitrate and nitrite. The wastewater quality index (WWQI) was determined to assess the effluent quality and the efficiency of the treatment plant used, showing a maximum of 71% quality improvement, thus suggesting that the treated wastewater could be discharged into aquatic environments. After 30 days, NH4+ demonstrated a high removal efficiency (higher than 98%), while NO3+ and NO2+ had a removal efficiency of 70% and 54%, respectively. The removal efficiency for metals was observed as follows (%): Mn > Cd > Cr > Zn > Fe > Ni > Co > Cu > Ba > Pb > Sr. Analysis of the microbial diversity in the zeolite samples indicated that the bacteria are formed due to the existence of nutrients in wastewater which favor their formation. In addition, the zeolite was characterized by SEM and the results indicated that the zeolite acts as an adsorbent for the pollutants and, moreover, as a support material for microbial community formation under optimal conditions. Comparing the two studied zeolites, NZ1 (particle size 1–3 mm) was found to be more suitable for wastewater treatment. Overall, the natural zeolite demonstrated high potential for pollutant removal and biomass support for bacteria community growth in wastewater treatment.

Yaqiong Gu, Beiying Li, Xiang Zhong et al.

Water • 2022

Bacterial diversity and community composition are of great importance in wastewater treatment; however, little is known about the diversity and community structure of bacteria in tropical municipal wastewater treatment plants (WWTPs). Therefore, in this study, activated sludge samples were collected from the return sludge, anaerobic sludge, anoxic sludge, and aerobic sludge of an A2O WWTP in Haikou, China. Illumina MiSeq high-throughput sequencing was used to examine the 16S ribosomal RNA (rRNA) of bacteria in the samples. The microbial community diversity in this tropical WWTP was higher than in temperate, subtropical, and plateau WWTPs. Proteobacteria, Bacteroidota, Patescibacteria, and Chloroflexi were the dominant phyla. Nitrification bacteria Nitrosomonas, and Nitrospira were also detected. Tetrasphaera, instead of Candidatus Accumulibacter, were the dominant polyphosphate accumulating organisms (PAOs), while, glycogen accumulating organisms (GAOs), such as Candidatus Competibacter and Defluviicoccus were also detected. The bacterial community functions predicted by PICRUSt2 were related to metabolism, genetic information processing, and environmental information processing. This study provides a reference for the optimization of tropical municipal WWTPs.

Bin Ji, Siqi Fan, Y. Liu

SSRN Electronic Journal • 2022

This study developed a continuous-flow non-aerated microalgal-bacterial granular tubular reactor for aquaculture wastewater treatment under natural day-night conditions. Results showed that daytime was favorable for ammonia removal while nighttime for nitrate removal. Over 99% of nitrite-N could be removed over the day-night cycles at a hydraulic retention time of 6 h. However, the phosphorus removal was found to be sensitive to the weather condition, ranging from 35.3% to 96.6%. It was also observed that dissolved oxygen produced by microalgae in daytime was sufficient for creating a 6-h aerobic condition in nighttime for sustaining heterotrophic activity. Chlorella and Leptolyngbya were identified as the most abundant algae related to weather changes. Metagenomics analysis revealed that the high nitrite removal relied mainly on nitrite reduction. These experimental findings offer new insights into the non-aerated microalgal-bacterial granular sludge for environmentally sustainable aquaculture wastewater treatment.

M. Dueholm, M. Nierychlo, K. S. Andersen et al.

bioRxiv (Cold Spring Harbor Laboratory) • 2021

Microbial communities are responsible for biological wastewater treatment, but our knowledge of their diversity and function is still poor. Here, we sequence more than 5 million high-quality, full-length 16S rRNA gene sequences from 740 wastewater treatment plants (WWTPs) across the world and use the sequences to construct the ‘MiDAS 4’ database. MiDAS 4 is an amplicon sequence variant resolved, full-length 16S rRNA gene reference database with a comprehensive taxonomy from domain to species level for all sequences. We use an independent dataset (269 WWTPs) to show that MiDAS 4, compared to commonly used universal reference databases, provides a better coverage for WWTP bacteria and an improved rate of genus and species level classification. Taking advantage of MiDAS 4, we carry out an amplicon-based, global-scale microbial community profiling of activated sludge plants using two common sets of primers targeting regions of the 16S rRNA gene, revealing how environmental conditions and biogeography shape the activated sludge microbiota. We also identify core and conditionally rare or abundant taxa, encompassing 966 genera and 1530 species that represent approximately 80% and 50% of the accumulated read abundance, respectively. Finally, we show that for well-studied functional guilds, such as nitrifiers or polyphosphate-accumulating organisms, the same genera are prevalent worldwide, with only a few abundant species in each genus. Microbial communities are responsible for biological wastewater treatment. Here, Dueholm et al. generate more than 5 million high-quality, full-length 16S rRNA gene sequences from wastewater treatment plants across the world to construct a database with a comprehensive taxonomy, providing insights into diversity and function of these microbial communities.

R. Oruganti, Keerthi Katam, P. Show et al.

Bioengineered • 2022

ABSTRACT The scarcity of water resources and environmental pollution have highlighted the need for sustainable wastewater treatment. Existing conventional treatment systems are energy-intensive and not always able to meet stringent disposal standards. Recently, algal-bacterial systems have emerged as environmentally friendly sustainable processes for wastewater treatment and resource recovery. The algal-bacterial systems work on the principle of the symbiotic relationship between algae and bacteria. This paper comprehensively discusses the most recent studies on algal-bacterial systems for wastewater treatment, factors affecting the treatment, and aspects of resource recovery from the biomass. The algal-bacterial interaction includes cell-to-cell communication, substrate exchange, and horizontal gene transfer. The quorum sensing (QS) molecules and their effects on algal–bacterial interactions are briefly discussed. The effect of the factors such as pH, temperature, C/N/P ratio, light intensity, and external aeration on the algal-bacterial systems have been discussed. An overview of the modeling aspects of algal-bacterial systems has been provided. The algal-bacterial systems have the potential for removing micropollutants because of the diverse possible interactions between algae-bacteria. The removal mechanisms of micropollutants – sorption, biodegradation, and photodegradation, have been reviewed. The harvesting methods and resource recovery aspects have been presented. The major challenges associated with algal-bacterial systems for real scale implementation and future perspectives have been discussed. Integrating wastewater treatment with the algal biorefinery concept reduces the overall waste component in a wastewater treatment system by converting the biomass into a useful product, resulting in a sustainable system that contributes to the circular bioeconomy. Graphical Abstract

M. Medina, U. Neis

Water Science and Technology • 2007

Algal incorporation into the biomass is important in an innovative wastewater treatment that exploits the symbiosis between bacterial activated sludge and microalgae (Chlorella vulgaris sp. Hamburg). It allows a good and easy algae separation by means of clarification. The effect of process parameters food to microorganisms ratio (F/M) and hydraulic retention time (HRT) on the process performance, evaluated by settleability, microalgae incorporation to biomass and nutrient removal, was studied. HRT hinted at a significant influence in the growth rate of algae, while F/M turned out to be important for stability when algae are incorporated into the biomass. This parameter also affects the total nitrogen removal of the treatment. Stable flocs with incorporated algae and supernatants with low free swimming algae concentrations were obtained at high HRT and low F/M values.

Tadashi Shoji, Shuichi Ochi, Masaaki Ozaki

Water Science and Technology • 2008

The concern with wastewater reuse as a sustainable water resource in urban areas has been growing. For the reclamation and distribution of wastewater, biofilm development deserves careful attention from the point of view of its promotion (e.g. biofiltration) and inhibition (e.g. clogging and hygiene problems). As the first step to control biofilm development, bacterial biofilm communities in tertiary treatment processes were characterized by using molecular biological methods. The result of clone library analysis showed that Nitrospirae-related (nitrite-oxydizing bacteria) and Acidobacteria-related (probably oligotrophic bacteria) groups were dominant. The ratio of the Nitrospirae-related group to the Acidobacteria-related group was associated with ammonia load, whereas other operational conditions (process, media, temperature, salt) did not clearly affect the phylum-level community or the dominant sequence of nitrifying bacteria. The result of real-time PCR also indicated that high ammonia load promotes the proliferation of nitrite- and ammonia-oxidizing bacteria. Regarding water supply systems, some researchers also have suggested the dominance of Nitrospirae- and Acidobacteria-related groups in biofilm formed on water distribution pipes. In tertiary wastewater treatment, therefore, it is concluded that oligotrophic and autotrophic bacteria are the dominant groups in biofilm samples because assimilable organic carbon is too poor to proliferate various heterotrophic bacteria.

J. B. Carberry, C. M. Brunner

Water Science and Technology • 1991

Carberry's proposed algal bacterial clay treatment (ABCT) process would generate an algal biomass, useful as a food source. This study examined the diurnal fluctuations resulting from alternating light-dark periods and the magnitude of resulting O2, CO2, and pH oscillations. The magnitude of these oscillations was studied under controlled conditions, in order to determine acceptable limits of these fluctuations. The effects of progressive drifts for these parameter values under uncontrolled conditions was also studied in order to determine the rate of decreasing wastewater bacterial biodegradation efficiency and rate of deterioration of algal biomass viability. Experiments were conducted in which algae, bacteria, and substrate were combined at various concentrations in a biostat. Dissolved gas concentrations and pH were continuously recorded; biomass and substrate concentrations were determined over time by periodic sampling. A 12-hour light/dark cycle simulated the natural diurnal light variation. Based on results from these runs, two computer programs were developed to predict the changes in these parameters over a 24-hour period. One model, incorporating redox potential, appeared to be more sensitive to changes in the aqueous environment than the model based on COD. pH values of less that 5 were found to cause system failure due to a continuing decrease in algal concentration. No critical levels were found for either O2 or CO2 although the duration of time spent at a dissolved oxygen concentration of zero depended on initial algal concentration.

Amir H. Tehrani, Kimberley A. Gilbride

MicrobiologyOpen • 2018

Abstract The conventional biological treatment process can provide a favorable environment for the maintenance and dissemination of antibiotic‐resistant bacteria and the antibiotic resistance genes (ARG) they carry. This study investigated the occurrence of antibiotic resistance in three wastewater treatment plants (WWTP) to determine the role they play in the dissemination of ARGs. Bacterial isolates resistant to tetracycline were collected, and tested against eight antibiotics to determine their resistance profiles and the prevalence of multiple antibiotic resistance. It was found that bacteria resistant to tetracycline were more likely to display resistance to multiple antibiotics compared to those isolates that were not tetracycline resistant. Polymerase chain reaction (PCR) was used to identify the tetracycline resistance determinants present within the bacterial communities of the WWTPs and receiving waters, and it was found that ARGs may not be released from the treatment process. Identification of isolates showed that there was a large diversity of species in both the tetracycline‐resistant and tetracycline‐sensitive populations and that the two groups were significantly different in composition. Antibiotic resistance profiles of each population showed that a large diversity of resistance patterns existed within genera suggesting that transmission of ARG may progress by both horizontal gene and vertical proliferation.

G. Gutzeit, D. Lorch, A. Weber et al.

Water Science and Technology • 2005

An innovative technology for the biological treatment of wastewater in regions with sufficient solar radiation based on the simultaneous growth and degradation processes of algal and bacterial biomass is presented. The aim of the work is the improvement of pond technology through the formation of stable algae–bacteria aggregates, which a) permit a simple separation of the algal biomass by gravity sedimentation, b) enable a high removal efficiency for organic carbon and nutrients, and c) are independent in terms of oxygen provision through algal photosynthesis. Algae–bacteria aggregates could be developed with a suitable algal species (Chlorella vulgaris, Strain Hamburg) as a ‘model organism’ in a wastewater environment. The morphology of algal–bacterial flocs is similar to activated sludge flocs. They are stable and settle quickly. Floc size ranged between 400 and 800μm. Results of our experiments with an artificially irradiated lab-scale system, operated in continuous flow mode, revealed that even at a relatively short hydraulic detention time of two days, a high elimination capacity of 9.96g Nm−2d−1 and 0.87g Pm−2d−1 can be achieved. Recent investigations confirmed that floc formation of unicellular algae and wastewater bacteria also could be developed and maintained in a pilot-scale system with a water depth of 0.5m.

N.P. Dan, C. Visvanathan, C. Polprasert et al.

Water Science and Technology • 2002

Two laboratory-scale membrane bioreactor systems were investigated to treat high salinity wastewater containing high organic (5,000 mg/L COD) and salt content (32 g/L NaCl), namely: (1) the Yeast Membrane Bioreactor (YMBR) and; (2) Yeast pretreatment followed by Bacterial Membrane Bioreactor (BMBR). In the YMBR system, experimental runs were conducted with a mean biomass concentration of 12 g MLSS/L. Here the maximum COD removal rate of 0.93 g COD/g MLSS.day was obtained at F/M of 1.5 g COD /g MLSS.d. Whereas, the BMBR system was operated with a biomass concentration of up to 25 g MLSS/L, resulting in maximum COD removal rate of 0.32 kg COD /kg MLSS.day at F/M ratio of 0.4. In comparison to BMBR, YMBR could obtain higher COD removal rate at higher organic loading, indicating the potential of a yeast reactor system to treat high salinity wastewater containing high organic concentration. Transmembrane pressure in BMBR was progressively increased from 2 to 60 kPa after 12 d, 6 d and 2 d at a hydraulic retention time (HRT) of 14 h, 9 h and 4 h, with average biomass concentration of 6.1, 15 and 20 g MLSS/L, respectively. Whereas the transmembrane pressure in YMBR has increased from 2 to 60 kPa only after 76 days of operation, with an average biomass concentration of 12 MLSS/L and an operating HRT range of 5-32 h.

Saufie S, Estim A, Shaleh SRM et al.

International Journal of Water and Wastewater Treatment • 2022

Effluents from aquaculture systems contain large volumes of chemical substances and microbial load such as polychlorinated biphenyls and antibiotics that are often used to control infection and pathogenic bacteria originating from feed or water. These substances, if discharged, create pollution in the aquatic environment. Mitigating this problem requires implementing appropriate treatment methods. This study investigated the efficiency of uptake of nutrients in the wastewater and reduction of microbial pollution by chitosan. This product is a linear polysaccharide composed of β-linked D-glucosamine and N-acetyl-D-glucosamine and can be extracted from the shells of shrimps, lobsters, crabs and other crustaceans that are discarded in bulk quantities by seafood restaurants. The performance of laboratory-produced chitosan (S1) which was prepared from shells of Pacific white leg shrimp (Litopenaeus vannamei) was compared with that of the commercial grade chitosan (S2). While the latter was more effective in nitrogen and phosphorus removal and reduction of total faecal coliform, the two products were comparable in the uptake of minerals from the effluents from a tilapia culture system. The results showed that S1 and S2 adsorbed the nutrients from aquaculture effluents, especially ammonia (NH4 + ), nitrite (NO2 - ), nitrate (NO3 - ) and phosphate (PO4 3-). However, differences were evident in terms of the efficiency of their removal and duration of treatment required for the purpose. In this respect, S2 performed better. Moreover, the anti-bacterial activity of S2 was higher than that of S1, and this appeared to be linked to differences in surface features of the two products. The chitosan extracted from shrimp waste and processed locally provides a low-cost solution to the environmental problems caused by aquaculture effluents.

Hélène Percherancier, Bernadette Volat, Bernard Montuelle

Water Science and Technology • 1996

A simple procedure of batch experiments is described allowing the determination of the Biodegradable Dissolved Organic Carbon (BDOC) content of different effluent outfalls from wastewater treatment plants. The bioassay is based on the DOC reduction of treated wastewater samples inoculated with natural consortia of bacteria taken from river sediments or aquarium filters. This test allows routine determination of BDOC within a short period of time (less than 8 days). BDOC represents a still significant proportion of the treated effluent DOC: from 50% to about 70%, depending on the effluent. The origin of bacterial inocula have no influence on these proportions, but are the main parameter for the rate of biodegradation. Testing the biodegradability at 10°C and 20°C appears to be significant as it influences biodegradation processes and must be done for a complete ecological evaluation of the biodegradability of wastewater treatment plant effluents.

Shashirekha Viswanaathan, Pitchurajan Krishna Perumal, Seshadri Sundaram

Sustainability • 2022

Increasing concentrations of carbon dioxide (CO2), one of the important greenhouse gases, due to combustion of fossil fuels, particularly burning coal, have become the major cause for global warming. As a consequence, many research programs on CO2 management (capture, storage, and sequestration) are being highlighted. Biological sequestration of CO2 by algae is gaining importance, as it makes use of the photosynthetic capability of these aquatic species to efficiently capture CO2 emitted from various industries and converting it into algal biomass as well as a wide range of metabolites such as polysaccharides, amino acids, fatty acids, pigments, and vitamins. In addition, their ability to thrive in rugged conditions such as seawater, contaminated lakes, and even in certain industrial wastewaters containing high organic and inorganic nutrients loads, has attracted the attention of researchers to integrate carbon capture and wastewater treatment. Algae offer a simple solution to tertiary treatments due to their nutrient removal efficiency, particularly inorganic nitrogen and phosphorus uptake. The algal–bacterial energy nexus is an important strategy capable of removing pollutants from wastewater in a synergistic manner. This review article highlights the mechanism involved in biological fixation of CO2 by microalgae, their cultivation systems, factors influencing algal cultivation in wastewater and CO2 uptake, the effect of co-cultivation of algae and bacteria in wastewater treatment systems, and challenges and opportunities.

K. K. Chin, S. L. Ong, L. H. Poh et al.

Water Science and Technology • 1996

Commercially available bacterial products were used in enhancing biodegradation of monoaromatic hydrocarbons in an attached-growth bioreactor and the treatment of wastewaters containing high concentration levels of organic wastes. For the augmented attached growth system empty bed hydraulic retention times (EBHRT) of 1.9 hours to 11.6 hours were run. Results showed that at 11.6 hour EBHRT 80% removal of 10.8 mg/L feed benzene, 96.8% removal of 8.1 mg/L feed toluene and 12.7% removal of 6.1 mg/L feed xylene were achieved. In the treatment of high strength sewage, significant removal of COD, BOD and oil and grease was observed over a 4 month trial run period.

M. Garcia, E. Bécares

Water Science and Technology • 1997

A comparative study on the removal of several pathogenic bacteria and their indicators was carried out at three natural wastewater treatment systems: stabilisation pond, high-rate algal pond and a free-water macrophyte system, retention times being 24, 5 and 3 days respectively. The macrophyte system showed higher removal efficiency for most of the groups, followed by stabilisation pond and high rate algal pond. All systems showed their highest efficiencies in the reduction of total coliforms, ranging from 98.68% for the stabilisation pond to 99.48% for the macrophyte process. Highly significant differences were found between the systems for bifidobacteria, C. perfringens and total coliforms removal. Pathogens and their indicators showed a different behaviour in their daily removal rate depending on the treatment plant.

V. Tare, P.C. Sabumon

Water Quality Research Journal • 1995

Abstract This investigation attempted to advance the state of the art of the process which utilizes the symbiotic relationship between the sulfate-reducing bacteria (SRB) and sulfide oxidizing bacteria (SOB) for degradation of organic matter present in wastewater. Major emphasis has been on the development of the desired microbial system without any external seed and comparative evaluation of the two types of multistage reversing flow bioreactor (MRB) systems. Biological vessels (BVs) in the MRB systems simulate conditions which correspond to configurations described as upflow sludge blanket and stationary fixed film. Two bench-scale models – one designed to achieve self granulation of sludge (SGS), and the second designed to promote growth of SRB/SOB on additional nonreactive surface – were set up and operated over a period of 4 months. Domestic wastewater supplemented with organic matter from sugar cane molasses was used as feed to develop the desired microbial population. Several visual and microscopic observations confirmed the presence of a significant number of SRB and SOB in all the biological vessels. Results indicated that it is possible to develop SGS and a microbial population of SRB and SOB which could attach to the nonreactive surface without any external seeding. Domestic wastewater could serve as a source of these organisms. Immobilized growth conditions and suspended growth conditions in BVs yield similar results in terms of organic matter utilization. The empirical formula for MRB biomass can be expressed as C11O12H36N5S.

Elena Diaz, Victor Monsalvo, Jose Palomar et al.

Encyclopedia of Inorganic and Bioinorganic Chemistry • 2016

Abstract Ionic liquids (ILs) are probably the kind of chemical compounds that have been most intensively investigated in the past 10 years. The potential applications of ILs cover practically all disciplines of chemistry, having received particular attention in separation processes, catalysis, electrochemistry, nanotechnology, and material science. This increasing use promotes the synthesis and application of the new IL compounds at larger scales. As a consequence, a parallel effort has been made by the scientific community to evaluate the potential environmental hazards of ILs. With equal focus, several researches have also made relevant progress in the development of effective treatments to recover or remove ILs from wastewaters and soils. Certainly, the current state of art in the field of ILs results from the cooperative and multidisciplinary work of experts from different scientific fields. In this work, the toxicity and biodegradability of ILs have been revised from the point of view of environmental engineers, centering the analysis on the expected need of managing ILs in a wastewater treatment plant (WWTP). For this purpose, the available standard tests and other methods to evaluate the toxicity of potential xenobiotic compounds are summarized. An overview of the reported toxicities of ILs toward different assays is presented, with particular emphasis in the available guidelines for designing ILs with low toxicity. The standardized tests for determining the biodegradability of xenobiotics are also collected and described. Lastly, the biodegradation behavior of ILs have been summarized, as evidenced in the bibliography, depending on their structural features and the biological systems used in the bioassays. Preliminary analysis, focused on relevant aspects on the toxicity and biodegradability of ILs, was performed in our laboratory using activated sludge. The main aim is to provide useful guidelines for the future development of biological processes for treating wastewater contaminated with ILs in a WWTP.

Luboš Stříteský, Radka Pešoutová, Petr Hlavínek

Water Science and Technology • 2015

This paper deals with biological treatment of malt house wastewater using algal-bacterial flocs. During three months of testing, optimisation of growth conditions and biomass separation leads to maximisation of biomass production, improved flocs settleability and increased pollutant removal efficiency while maintaining low energy demand. At a high food to microorganism ratio (0.16 to 0.29 kg BOD5 kg−1 TSS d−1), the biological oxygen demand (BOD5), chemical oxygen demand (CODCr), total phosphorus (Ptot) and total suspended solids (TSS) removal efficiencies were all higher than 90%. At a food to microorganism ratio of 0.06 kg BOD5 kg−1 TSS d−1, BOD5, CODCr, total nitrogen (Ntot), Ptot and TSS removal efficiencies of 99.5%, 97.6%, 91.5%, 97.8% and 98.4%, respectively, were achieved. The study also proved a strong dependence of removal efficiencies on solar radiation. The results suggest the algae-bacteria system is suitable for treatment of similar wastewater in locations with available land and sufficient solar radiation and temperature during the whole year.

J. B. Carberry, R. W. Greene

Water Science and Technology • 1992

A computer model is presented for an innovative wastewater treatment process known as the Algae-Bacterial-Clay Treatment (ABCT) system. In this process the photosynthetic production of dissolved oxygen by algae supports the bacterial breakdown of organic matter in wastewater. Clay is added to the plug flow reactor to dampen input BOD variation. The model was developed to gain an improved understanding of transient behavior of dissolved oxygen and pH in the treatment reactor during typical operation. The model consists of five nonlinear ordinary differential equations describing the time rate of change of algae mass, bacterial mass, organic substrate, dissolved oxygen, and dissolved carbon dioxide. A fourth-order Runge-Kutta integration technique was used to predict system response at discrete time steps. The pH variation expected from changes in dissolved carbon dioxide was based upon presumptions that the system is buffered by the carbonic acid system, and that alkalinity does not change appreciably during the course of time. These assumptions were confirmed by experimental results. The model successfully predicted diurnal fluctuations in dissolved oxygen, carbon dioxide, and pH in the ABCT process. The model predicted that algae will supply sufficient oxygen during sunny and partly sunny days to eliminate the need for continuous mechanical aeration. This feature should result in significant cost savings over conventional secondary wastewater treatment schemes. Surplus dissolved oxygen produced by algae during the day should be completely depleted at night due to bacterial respiration. This lack of oxygen, in turn, resulted in reduced substrate utilization and potential effluent discharge violations. Mechanical aeration during the night might be one possible remedial strategy. Despite its dynamic behavior, the ABCT process would be a viable and potentially cost efficient wastewater treatment strategy.

Fuad Ameen

Biology • 2023

Environmental pollutants such as toxic heavy metals and oxygen-demanding solids are generated by leather manufacturing. In most tanneries, wastewaters are treated with physico-chemical methods but overly high levels of pollutants remain in surface waters. The efficiency of tanning wastewater treatment with conventional techniques was evaluated in four tanneries in Saudi Arabia. It was observed that the wastewaters contained high amounts of pollutants, needing further treatment. We isolated microorganisms from the wastewaters and carried out experiments to treat the effluents with different bacteria, fungi, and their consortia. We hypothesized that a consortium of microorganisms is more efficient than the single microorganisms in the consortium. The efficiency of five single bacterial and five fungal species from different genera was tested. In a consortium experiment, the efficiency of nine bacterial–fungal consortia was studied. The bacterium Corynebacterium glutamicum and the fungus Acremonium sp. were the most efficient in the single-microbe treatment. In the consortium treatment, the consortium of these two was the most efficient at treating the effluent. The factory wastewater treatment reduced total dissolved solids (TDS) from 1885 mg/L to 880 mg/L. C. glutamicum treatment reduced TDS to 150 mg/L and Acremonium sp. to 140 mg/L. The consortium of these two reduced TDS further to 80 mg/L. Moreover, the factory treatment reduced BOD from 943 mg/L to 440 mg/L, C. glutamicum to 75 mg/L, and Acremonium sp. 70 mg/L. The consortium reduced BOD further to 20 mg/L. The total heavy-metal concentration (Cd, Cr, Cu, Mn, and Pb) was reduced by the factory treatment from 43 μg/L to 26 μg/L and by the consortium to 0.2 μg/L. The collagen concentration that was studied using hydroxyproline assay decreased from 120 mg/L to 39 mg/L. It was shown that the consortium of the bacterium C. glutamicum and the fungus Acremonium sp. was more efficient in reducing the pollutants than the single species. The consortium reduced almost all parameters to below the environmental regulation limit for wastewater discharge to the environment in Saudi Arabia. The consortium should be studied further as an additional treatment to the existing conventional tannery wastewater treatments.

Bahareh Pirzadeh

Wastewater Treatment • 2022

Water is a valuable material. Water used to dispose of nature or enter the consumption cycle requires disinfection and purification to conserve water resources as well as to provide drinking water. Different processes are carried out on the water to increase water quality as much as possible. In general, the filtration process can be divided into two general categories. In the first process, harmful substances are removed from the water. In the second group, the processes are specifically designed to improve the quality and control parameters such as the pH value. The stages of water purification can be divided into different steps more in detail, which physical purification is one of these steps and has been discussed in this chapter.

Franck Michael ZAHUI, Jean-Marie Pétémanagnan Ouattara, Mahamadou Kamagaté et al.

Research Square • 2021

Abstract Bacteria are frequently studied in constructed wetlands (CWs) due to their effective involvement in pollutants purification processes. In this study, aerobic, anaerobic and total bacteria densities and their vertical distribution profile within pilot-scale vertical flow CWs planted with different plant species were investigated. Five beds were planted in monoculture with Andropogon gayanus, Chrysopogon zizanioides, Echinochloa pyramidalis, Pennisetum purpureum and Tripsacum laxum , and one unplanted bed was used as control. At the end of the treatment trial, bacteria were collected by taking cores of sediment samples at the corners and the center of each bed following six layers in the vertical profile. In fact, the presence of plants on CWs improved the bacterial density and removal efficiencies in the system, with yields from 5.9 to 24.1% regardless the pollutant. However, few anaerobic bacteria were obtained in the different wetlands, and unable to reduce NO 3 − , excluding for beds planted with T. laxum and P. purpureum . Besides, the number of aerobic bacteria determined decreased ( i.e. , 17.4 10 6 to 0.1 10 6 CFU.g − 1 ), while that of anaerobic bacteria increased ( i.e. , 0.1 10 6 to 2.1 10 6 CFU.g − 1 ) from the upper to the bottom layers in the planted beds. Otherwise, anaerobic bacteria were more abundant in the control than in planted beds. Then, total bacteria were dominated by aerobic bacteria, and decreased from surface toward the bottom. As P purpureum promotes the best performance, CWs with this type of plant could be a cost-effective alternative method of treating wastewater.

J. Han, L. Y. Wang, B. Y. Cai

Water Science and Technology • 2013

The bacterial diversity of an antibiotic industrial wastewater treatment system was analyzed to provide the information required for further optimization of this process and for identification of bacterial strains that perform improved degradation of antibiotic industrial wastewater. The total bacterial DNA of samples collected at three stages (aeration, precipitation, and idle) during the sequencing batch reactor (SBR) process were analyzed by polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) of the 16 s rDNA V3 regions. Community analysis was conducted in terms of the richness value (S), the dominance degree and the Shannon–Wiener diversity index (H). Rich bacterial diversity was apparent in the aeration stage of the SBR process, and the number of bands in the aeration stage was more abundant than that in the precipitation and idle stages. The DGGE analysis showed 15 bands, six of which were uncultured bacteria, and included one anaerobic and five aerobic bacteria. The microbial community in the aeration stage was the most complex of the whole SBR process, while the dominant bacteria differed in each reaction stage. These results demonstrate the cyclical dynamic changes in the bacterial population during the SBR process for the treatment of antibiotic industrial wastewater.

K. Sankaran, Lakshmi Pisharody, G. Suriya Narayanan et al.

RSC Advances • 2015

Treatment of ADSW with culture rich in Pseudomonas sp. resulting benefits such as improved physico-chemical characteristics; biomass availability for energy generation; easy operation of subsequent downstream units of effluent treatment plant.

A. Rada-Ariza, C. Lopez-Vazquez, N. P. Van der Steen et al.

Algal Systems for Resource Recovery from Waste and Wastewater • 2023

Abstract Nitrogen-rich wastewaters (10–400 mg N/L) are produced by municipal, industrial and agricultural wastes, including effluents from anaerobic treatment processes. These represent a risk to the environment due to the high nutrient concentrations (nitrogen and phosphorous), which can cause eutrophication of water bodies, deteriorating the quality of the ecosystems. As a solution, the nitrogen removal capacity of a novel bio-treatment system, the photo-activated sludge (PAS), composed of microalgae and bacteria consortia can be applied. Photobioreactors used for the simultaneous cultivation of microalgae and bacteria under sequencing batch conditions showed that microalgal–bacterial consortia can remove ammonium 50% faster than solely microalgal consortia. The increase in ammonium removal rates is due to the action of nitrifying bacteria, supplied with oxygen produced by the algae. The microalgal–bacterial system offers the possibility of reducing the hydraulic retention time, which can decrease the large area requirements often demanded by algal systems. The SRT is the main parameter to control the efficiency of the technology. The control of the suspended solids concentration, by adjusting the SRT, influences the light penetration within the reactor, which can limit or enhance the oxygen production of the algae. The photo-activated sludge system using microalgal–bacterial consortia is a sustainable treatment option for ammonium-rich wastewaters, providing clean effluents and opening reuse options for the biomass.

Donghan Kang, Keugtae Kim

Processes • 2021

Algal–bacterial consortium is a promising technology, combined with wastewater treatment plants, because algae produce molecular oxygen for nitrification and organic removal and reduce carbon dioxide emissions. However, algal–bacterial consortia based on suspended growth require a relatively long hydraulic retention time (HRT) of 4 d to 6 d for removal of organic matter and nutrients. For the algal–bacterial consortia in a photobioreactor (PBR) containing a moving bed, the organic matter and nutrient removal and the community structure of algal–bacterial consortia were investigated to determine the performance under a relatively short HRT of 2.5 d. Moving media containing algal–bacterial consortia enhanced the photosynthetic oxygen concentration (0.2 mg dissolved oxygen (DO)·L−1 to 5.9 mg DO·L−1), biochemical oxygen demand removal (88.0% to 97.2%), ammoniacal nitrogen removal (33.8% to 95.3%), total nitrogen removal (61.6% to 87.7%), total phosphate removal (66.4% to 88.7%), algal growth (149.3 mg algae·L−1 to 285.4 mg algae·L−1), and settleability (algae removal efficiency of 20.6% to 71.2%) compared with those of a PBR without moving media (SPBR). Although biomass uptake was the main mechanism for nutrient removal in the SPBR, both biomass uptake and denitrification were the main mechanisms in the PBR with moving media (MBPBR). The bacterial community also changed under the moving media condition. This study shows that moving media might be an essential parameter for PBRs with a short HRT to enhance nutrient removal and settleability.

Yongfeng Wang, Qiang He

Encyclopedia of Water • 2019

Abstract Anaerobic treatment technology, represented by anaerobic digestion, is an important microbial process for wastewater treatment. Anaerobic treatment is superior to aerobic processes with reduced energy demand, lower excess sludge production, and the generation of methane as a source of renewable energy. In anaerobic treatment, organic waste is converted into methane and carbon dioxide via four successive steps – hydrolysis, acidogenesis, acetogenesis, and methanogenesis. The interactions between microbial populations have major impacts on the performance of anaerobic treatment processes. The competition between populations of Firmicutes and Bacteroidetes is closely correlated to process stability. Similarly, the competition between two acetoclastic methanogens with distinct kinetics characteristics, i.e. Methanosaeta and Methanosarcina , is linked to changes in the level of acetate as a metabolic intermediate associated with process perturbations. Further, syntrophic interactions between the Bacteria and Archaea play central roles in maintaining process balance. Indeed, syntrophic interactions are required for the conversion of diverse intermediates and substrates, including organic acids, alcohols, and aromatics, in anaerobic treatment. The microbial interactions underlying anaerobic treatment are critical to process performance. The availability of new tools, such as high‐throughput sequencing technologies, makes it possible to gain further understanding of population interactions at the microbiome level in order to develop more robust anaerobic treatment processes for broader applications as sustainable alternatives.

Victor Odhiambo Shikuku, Wilfrida N. Nyairo, Chrispin O. Kowenje

Advances in Environmental Engineering and Green Technologies • 2019

Biochars have been extensively applied in soil remediation, carbon sequestration, and in climate change mitigation. However, in recent years, there has been a significant increase in biochar research in water treatment due to their stupendous adsorptive properties for various contaminants. This is attributed to their large surface areas, pore structures, chemical compositions, and low capital costs involved making them suitable candidates for replacing activated carbons. This chapter discusses the preparation methods and properties of biochars and their removal efficacy for organic contaminants and microbial control. Factors affecting adsorption and the mechanisms of adsorption of organic pollutants on biochars are also concisely discussed. Biochars present environmentally benign and low-cost adsorbents for removal of both organic pollutants and microbial control for wastewater purification systems.

Sania Sahreen, Hamid Mukhtar

Microbial Bioremediation and Multiomics Technologies for Sustainable Development • 2024

Water pollution is continuously on the rise due to industrialization, rapid urbanization, agricultural activities, and global economic development. Developing countries directly discharge 80% of their untreated water, including industrial effluents, into water bodies without prior treatment. Finding a cost-effective, efficient, and environmentally friendly solution for industrial wastewater treatment remains a challenge. Floating treatment wetlands (FTW) offer an effective and sustainable technology for water treatment. This chapter presents a comprehensive overview of FTW as a promising solution for industrial wastewater treatment. The chapter begins by emphasizing the importance of sustainable industrial wastewater treatment and introduces FTW as a viable approach. Next, FTW classification, principal components, and basic structural and design considerations are discussed in detail. The chapter further addresses the significance and working mechanism of plant–bacteria partnership in wastewater treatment as crucial aspects of FTW. Additionally, FTW as sustainable industrial wastewater management tools are also discussed through supporting case studies. Lastly, care, maintenance, and associated challenges in FTW implementation for wastewater treatment and enhancement strategies to overcome these challenges were briefed. In conclusion, FTW present a valuable opportunity for transforming industrial wastewater treatment into a more ecologically balanced and sustainable practice.