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H. Muthukumar, M. K. Shanmugam, S. S. Dash et al.
Biological Treatment of Industrial Wastewater · 2021
Massive amounts of (anthropogenic) organic compounds have been released into the environment by industry, generating serious issues of environmental pollution. Currently, pharmaceuticals and personal care products are known as emerging organic pollutants and are the main contaminants of concern. Among the pollutants, caffeine is one of the obstinate compounds with a noxious effect on biological systems and it is necessary to eliminate caffeine from water. Caffeine is also considered an anthropogenic indicator for contamination of surface waters. In the past few years, physicochemical (advanced oxidation process, adsorption and filtration) and biological wastewater treatment methods have been developed and extensively used for the removal of pollutants. Currently, biological treatments and nanoparticle mediated photocatalytic processes have gained popularity for the removal of caffeine with high efficiency and low capital requirement. This chapter attempts to explain the challenges, pros, cons, multifaceted operation and time consumption involved in the physicochemical and biological treatment of caffeine.
Chatchada Ratanachan
· 2009
Biological treatment is an appropriate method used in treating organiccontaining wastewaters because of its environment safe and low treatment cost. In this research, two units of sequencing batch reactors (SBR) were used to study the biodegradation of biodiesel wastewater obtained from Bangchak Public Company Limited by using the sludge obtained from the activated sludge treating biodiesel wastewater. The SBR units, having an effective volume of 1.5 L, were operated on a fill-and-draw basis with four cycles per day at different chemical oxygen demand (COD) loading rates (0.05-0.60 kg/m³d) at room temperature. Since the studied wastewater lacked of nitrogen and phosphate, ammonium hydrogen carbonate (NH₄HCO₃) and di-potassium hydrogen orthophosphate (K₂HPO₄) were added as nutrients for the enhancement of biodiesel wastewater biodegradation. The results showed that when the COD loading rate increased, the removal efficiency decreased. Under the studied conditions, a maximum COD removal of 91.4% and TOC removal of 35.7% were achieved at the lowest COD loading rate of 0.05 kg/m³d. Moreover, the minimum F/M ratio and the highest MLSS were found to correspond to the lowest COD loading rate.
Aparna Yadu, Biju Prava Sahariah, J. Anandkumar
Biological Treatment of Industrial Wastewater · 2021
Water is a precious element on earth which was easily available in pure form a few decades ago. However, with the passage of time the scenario has changed and procurement of clean as well as safe water is become a challenging issue worldwide. This is mainly due to the huge amount of wastewater generated from various industrial activities which has gained significant attention all over the world. Industry uses a huge amount of freshwater for various activities and releases wastewater as a by-product. The wastewater produced from industry is of major environmental concern owing to the toxic and hazardous nature of pollutants which are a serious threat to the ecosystem. It is therefore imperative to make a concerted effort towards the reduction of water utilization and treatment of wastewater to make it reusable and suitable for safe discharge into the environment. This chapter focuses on providing information about various futuristic industrial wastewater treatments and management strategies to make it environmentally benign.
Hui Xu, Bo Yang, Yanbiao Liu et al.
Biological Treatment of Industrial Wastewater · 2021
Due to the high concentration of dissolved organic matter in wastewater and the limited efficiency of traditional physicochemical technology, high-salt wastewater has been regarded as one of the most difficult-to-treat industrial wastewaters. Alternatively, biological technology has been considered as a promising solution. However, due to the high-salt concentration, it can inhibit the growth of microorganisms in the biological treatment process, thus limiting its wide application in engineering. To date, some challenging issues still need to be solved, such as long start-up time and the complex processes of the biological technologies. This chapter summarizes the recent advances in the biological treatment of high-salt wastewater, especially the current limitations of the biological technologies and research into halophilic microorganisms.
Ranjana Das, Chiranjib Bhattacharjee
Biological Treatment of Industrial Wastewater · 2021
A membrane bioreactor (MBR) is a robust device in the biological wastewater treatment field, which has been applied in treating municipal as well as industrial wastewater, with its distinct advantages such as high treatment efficiency, small footprint, simpler operation, as well as high-quality solid-free effluent. MBR technology is well recognized as a promising alternative to the conventional activated sludge (CAS) process of wastewater treatment. MBRs provide the prospect of producing high-quality effluent for sensitive receiving water bodies and offers water recycling and reuse benefits. The MBR has also been categorised as the perfect pre-treatment operation in industrial applications as an alternative to nanofiltration or the reverse osmosis process. The advanced MBR technology has the potency to be applied both in municipal and industrial waste water treatment with optimization of operational cost and superior effluent quality. This chapter presents a comprehensive review of MBR technology, advanced and hybrid membrane bioreactor devices, and applications of MBR in major high-strength industrial wastewater treatment sectors, highlighting treatment performances, membrane-fouling control strategies, hybrid MBR systems for enhanced treatment performance, and MBR life-cycle assessment in various applications.
Aennes Abbas
· 2022
Clean water is fundamental to human health and ecosystem integrity. However, water quality deteriorates due to novel anthropogenic pollutants present at microgram per liter concentrations in urban water cycles (termed micropollutants). Wastewater treatment plants (WWTP) have been identified as major point sources for aquatic (micro-)pollutants. Chemical and ecotoxicological analyses have shown that conventional biological WWTPs do not fully remove micropollutants and associated toxicities, which is often because of mobile, polar and/or recalcitrant compounds and transformation products (TPs). To minimize possible environmental risks, advanced wastewater treatment (AWWT) technologies could be a promising mitigation measure. Multiple processes are therefore being developed and evaluated such as ozonation and ozonation followed by granulated activated carbon (GAC) or biological filtration. Assessing the performance of these combined AWWTs was the focus the TransRisk project. Within this project, this thesis accomplished four major goals. Firstly, the preparation of (waste)water samples was optimised for in vitro bioassays. Acidification, filtration and solid phase extraction (SPE) were tested for their impact on environmentally relevant in vitro endocrine activities, mutagenicity, genotoxicity and cytotoxicity. Significantly different outcomes of these assays were detected comparing neutral and acidified samples. Sample filtration had a lesser impact, but in some cases retention of particle-bound compounds could have caused significant toxicity losses. Out of three SPE sorbents the Telos C18/ENV at sample pH 2.5 extracted highest toxicity, some undetected in aqueous samples. These results indicate that sample preparation needs to be optimised for specific sample matrices and bioassays to avoid false-positive or -negative detects in effect-based analyses. Secondly, the above listed in vitro toxicities were monitored in a protected region for drinking water production in South-West Germany (2012-2015). Out of 30 sampling sites surface water and groundwater were the least polluted. Nonetheless, a few groundwater samples induced high anti-estrogenic activity that prompted further monitoring. The latter included a waterworks in which no toxicity was detected. Hospital wastewater also had elevated in vitro toxicities and hospitals are, thus, relevant intervention points for source control. The biological WWTPs were effective in removing most of the detected toxicity, and the selected bioassays proved to be pertinent tools for water quality assessment and prioritisation of pollution hotspots. Thirdly, the in vivo bioassay ISO10872 based on Caenorhabditis elegans (C. elegans) was adapted for this thesis. Using this model, a median effect concentration (EC50) for reproductive toxicity of the polycyclic aromatic hydrocarbon β-naphthoflavone (β- NF) of 114 µg/L was computed which is slightly lower than reported in the scientific literature. β-NF induced cyp-35A3::GFP (a biomarker in transgenic animals) in a time and concentration dependent manner (≤ 21.3–24 fold above controls). β-NF spiked wastewater samples supported earlier hypotheses on particle-bound pollutants. Reproductive toxicity (96 h) and cyp-35A3 induction (24 h) of biologically treated and/or ozonated wastewater extracts and growth promoting effects of GAC/biologically filtered ozonated wastewater extracts were observed. This suggested the presence of residual bioactive/toxic chemicals not included in the targeted chemical analysis. It also highlighted the importance of integrating multiple (apical and molecular) endpoints in wastewater assessments. Fourthly, five in vitro and the adapted C. elegans bioassay were integrated into a wastewater quality evaluation (developed within TransRisk). Out of the five AWWT options, ozonation (at 1 g O3,applied/g DOC, HRT ~ 18 min) combined with nonaerated GAC filtration was rated most effective for toxicity removal. All five AWWTs largely removed estrogenic and (anti-)androgenic activities, but not anti-estrogenic activity and mutagenicity, which even increased during ozonation. This has been observed in related studies and points towards toxic TPs. These results also emphasized the need for implementing an effective post-treatment for ozonation. The results from a parallel in vivo study with Lumbriculus variegatus and Potamopyrgus antipodarum conducted on site at the WWTP (using flow through systems) were in accordance with the C. elegans results. In this context, it is suggested to further implement C. elegans as sensitive, feasible and ecologically relevant model. In conclusion, this thesis shows how optimised sample preparation, long-term (in vitro) environmental monitoring, sensitive and ecologically relevant (in vivo) bioassays as well as innovative evaluation concepts, are pivotal in improving the removal of micropollutants and their toxicities with AWWTs. Future research should further develop and evaluate measures at sewer systems, conventional biological, tertiary and other advanced treatment technologies, as well as sociopolitical strategies (e.g., source control or natural conservation) and restoration projects. The effect-based tools optimised in this thesis will support assessing their success.
Shuang Xu, Junqin Yao, Meihaguli Ainiwaer et al.
BioMed Research International · 2018
Activated sludge bulking is easily caused in winter, resulting in adverse effects on effluent treatment and management of wastewater treatment plants. In this study, activated sludge samples were collected from different wastewater treatment plants in the northern Xinjiang Uygur Autonomous Region of China in winter. The bacterial community compositions and diversities of activated sludge were analyzed to identify the bacteria that cause bulking of activated sludge. The sequencing generated 30087–55170 effective reads representing 36 phyla, 293 families, and 579 genera in all samples. The dominant phyla present in all activated sludge were Proteobacteria (26.7–48.9%), Bacteroidetes (19.3–37.3%), Chloroflexi (2.9–17.1%), and Acidobacteria (1.5–13.8%). Fifty-five genera including unclassified_f_Comamonadaceae, norank_f_Saprospiraceae, Flavobacterium, norank_f_Hydrogenophilaceae, Dokdonella, Terrimonas, norank_f_Anaerolineaceae, Tetrasphaera, Simplicispira, norank_c_Ardenticatenia, and Nitrospira existed in all samples, accounting for 60.6–82.7% of total effective sequences in each sample. The relative abundances of Saprospiraceae, Flavobacterium, and Tetrasphaera with the respective averages of 12.0%, 8.3%, and 5.2% in bulking sludge samples were higher than those in normal samples. Filamentous Saprospiraceae, Flavobacterium, and Tetrasphaera multiplied were the main cause for the sludge bulking. Redundancy analysis (RDA) indicated that influent BOD5, DO, water temperature, and influent ammonia had a distinct effect on bacterial community structures.
M. Ikram, M. Zahoor, Gaber El-Saber Batiha
Zeitschrift für Physikalische Chemie · 2020
Abstract Textile industry releases large quantities of toxic dyes, which is a threat to public health and needs proper management before their release into environment. Out of the different approaches used these days, biodegradation and bio-decolorization is considered an eco-friendly and effective technique as this involves the use of microbes. This technique has the potential to be used effectively for a wide variety of dyes. In biological methods, mainly bacteria, fungi, and some algae are usually employed to remove or decolorize dyes present in textiles effluents and wastewaters. A number of researchers have used bacterial strains and relevant isolated enzymes successfully to decolorize a number of dyes. In this review article, various biological methods that have been used for the biodegradation and decolorization of textile dyes have been described. The review will also revive the significance of biological methods over other physical and chemical treatment methods that would be helpful in ensuring clean environment if used on large scale. Out of these methods, biodegradation through bacterial strains is considered as the best alternative to control water pollution as the growth rate of bacteria is considerably high as compared to other microorganisms. Thus if used the required biomass needed for biodegradation can be obtained in comparatively short interval of time.
Xueli Ma, Xu Dong, Jiabei Cai et al.
Frontiers in Microbiology · 2022
The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in hospital wastewater poses a great threat to public health, and wastewater treatment plants (WWTPs) play an important role in reducing the levels of ARB and ARGs. In this study, high-throughput metagenomic sequencing was used to analyze the bacterial community composition and ARGs in two hospitals exposed to different antibiotic use conditions (an eye specialty hospital and a general hospital) before and after wastewater treatment. The results showed that there were various potential pathogenic bacteria in the hospital wastewater, and the abundance and diversity of the influent ARGs in the general hospital were higher than those in the eye hospital. The influent of the eye hospital was mainly composed of Thauera and Pseudomonas, and sul1 (sulfonamide) was the most abundant ARG. The influent of the general hospital contained mainly Aeromonas and Acinetobacter, and tet39 (tetracycline) was the most abundant ARG. Furthermore, co-occurrence network analysis showed that the main bacteria carrying ARGs in hospital wastewater varied with hospital type; the same bacteria in wastewater from different hospitals could carry different ARGs, and the same ARG could also be carried by different bacteria. The changes in the bacterial community and ARG abundance in the effluent from the two hospitals showed that the activated sludge treatment and the direct chlorination disinfection can effectively remove some bacteria and ARGs in wastewater but have limitations. The species diversity increased significantly after the activated sludge treatment, while the direct chlorination disinfection did not increase the diversity. The activated sludge treatment has a better effect on the elimination of ARGs than the direct chlorination disinfection. In summary, we investigated the differences in bacterial communities and ARGs in wastewater from two hospitals exposed to different antibiotic usage conditions, evaluated the effects of different wastewater treatment methods on the bacterial communities and ARGs in hospital wastewater, and recommended appropriate methods for certain clinical environments.
I. Papajová, J. Šmigová, G. Gregová et al.
International Journal of Environmental Research and Public Health · 2022
Wastewater and wastewater treatment plants serve as urban reservoirs of pathogenic microorganisms. Wastewaters frequently contain bacteria, antibiotic-resistant bacteria, and developmental stages of parasites with significant zoonotic potential. Five wastewater treatment plants in the central part of Slovakia were investigated to determine the effect of treatment on bacterial community, antibiotic-resistant bacteria, and the occurrence of helminth eggs. Although all monitored chemical factors (chemical oxygen demand, biochemical oxygen demand, N-NH4, total nitrogen, and total phosphorus) in the effluent were in line with the legislative standards for discharge into public waterways, the results of minimal inhibitory concentrations show that reclaimed water harbors E. coli resistant to several commonly used antibiotics (ampicillin, piperacillin, and tazobactam, combine ampicillin and sulbactam, cefotaxime, tetracycline). The presence of endoparasite developmental stages in wastewater and sludge (Ascaris spp., Hymenolepis nana, eggs from the Ancylostomatidae family, Giardia duodenalis) indicates potential health risks for humans and workers at these sites. Treatment such as composting before applying sludge to land is necessary to reduce human pathogens.
Jiawen Xie, Ling Jin, Dong Wu et al.
Environmental Science & Technology · 2022
Antibiotic resistance genes (ARGs) are commonly detected in the atmosphere, but questions remain regarding their sources and relative contributions, bacterial hosts, and corresponding human health risks. Here, we conducted a qPCR- and metagenomics-based investigation of inhalable fine particulate matter (PM2.5) at a large wastewater treatment plant (WWTP) and in the ambient air of Hong Kong, together with an in-depth analysis of published data of other potential sources in the area. PM2.5 was observed with increasing enrichment of total ARGs along the coastal-urban-WWTP gradient and clinically relevant ARGs commonly identified in urban and WWTP sites, illustrating anthropogenic impacts on the atmospheric accumulation of ARGs. With certain kinds of putative antibiotic-resistant pathogens detected in urban and WWTP PM2.5, a comparable proportion of ARGs that co-occurred with MGEs was found between the atmosphere and WWTP matrices. Despite similar emission rates of bacteria and ARGs within each WWTP matrix, about 11-13% of the bacteria and >57% of the relevant ARGs in urban and WWTP PM2.5 were attributable to WWTPs. Our study highlights the importance of WWTPs in disseminating bacteria and ARGs to the ambient air from a quantitative perspective and, thus, the need to control potential sources of inhalation exposure to protect the health of urban populations.
Hebin Liang, Dongdong Ye, Pan Li et al.
RSC Advances · 2016
PCR-DGGE and Illumina HiSeq revealed the composition of bacterial communities in tannery sewage treatment and their linkages with the physicochemical characteristics of wastewater.
Sivakumar Kumaraguru, Rajesh Pandiyan
Nano LIFE · 2026
Hydrothermal synthesis stands out as a highly effective method for creating nanostructures due to its eco-friendly and straightforward process. In this study, we successfully produced sodium nitrate and nickel(II) chloride nanoparticles using hydrothermal methods. Sodium nitrate (NaNO[Formula: see text] and nickel(II) chloride hexahydrate (NiCl 2 ⋅6H 2 O) were synthesized through precise chemical methods. The resulting samples underwent thorough characterization and analysis using a range of advanced techniques, including UV–visible spectroscopy, microscopic analysis, FTIR, anti-bacterial activity testing, zeta potential measurement and SEM. The UV–visible spectroscopy results confirmed that the synthesized bimetallic Na–Ni nanoparticles possessed a size range of 300–600 nm. FTIR analysis identified the functional groups of the bimetallic Na–Ni nanoparticles, with peaks at 2853.016, 2080.025, 1607.706, 1363.261 and 834.847 cm[Formula: see text], corresponding to C–H stretching, C[Formula: see text]O stretching, N–H bending, O–H bending and C–H bending. Anti-bacterial activity tests demonstrated the effectiveness of the synthesized bimetallic Na–Ni nanoparticles against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacterial strains. Additionally, the study decisively showcased the capabilities of these bimetallic nanoparticles in dye degradation. Our findings revealed that these bimetallic nanoparticles can efficiently remove pollutants from highly contaminated water, rendering the treated water suitable for various applications, including agricultural use. Furthermore, we rigorously evaluated their performance as fertilizers. In seed germination experiments, they affirmed their potential in sustainable agriculture.
Mansi Mahajan, Alka Prakash
International Journal of Advancement in Life Sciences Research · 2025
Bioremediation has become a crucial technology to combat environmental pollution and waste management. This review amalgates the findings from several studies on the use of microorganisms precisely the immobilized bacterial consortia for the bioremediation of pollutants present in wastewater. The review features a variety of techniques such as use of electro spun bacterial nanofibers, microalgae predominant microbial consortia (MPMC) and other novel approaches to improve the efficiency of different bioremediation processes. This review also discusses the key challenges and future directions to present a thorough understanding of the existing condition and possible improvements in this field in the near future.
Lei Zhang, Yanan Cheng, Chang Qian et al.
Journal of Water and Health · 2020
Abstract Sewage pollution is a major threat to public health because sewage is always accompanied by pathogens. Generally, wastewater treatment plants (WWTP) receive and treat sewage to control pathogenic risks and improve environmental health. This study investigated the changes in the bacterial community over the course of treatment by a WWTP. Illumina MiSeq high-throughput sequencing was performed to characterize the bacterial communities in the WWTP. This study found that potential pathogens in the WWTP, especially the genera Arcobacter and Acinetobacter, were greatly reduced. In addition, high chemical oxygen demand levels provided excessive growth substrates for the genera Hyphomicrobium and Rhodoplanes, the abundance of which could exceed autotrophic bacteria, increasing the ammonium removal. According to the network analysis, the bacterial assemblage was not randomly arranged in the WWTP, and various defined processes led to higher intra-phylum (such as Proteobacteria) coexistence than expected. Moreover, the metabolic functions of bacterial communities significantly improved in the WWTP compared with the influent. Together, the data in this study emphasize the need to understand the bacterial community of WWTPs better. When analyzing the risks of WWTP drainage systems to the environment and human health, these data should be considered.
Feng Ju, Tong Zhang
The ISME Journal · 2015
Abstract Understanding environmental and biological influences on the dynamics of microbial communities has received great attention in microbial ecology. Here, utilizing large time-series 16S rRNA gene data, we show that in activated sludge of an environmentally important municipal wastewater treatment plant, 5-year temporal dynamics of bacterial community shows no significant seasonal succession, but is consistent with deterministic assemblage by taxonomic relatedness. Biological interactions are dominant drivers in determining the bacterial community assembly, whereas environmental conditions (mainly sludge retention time and inorganic nitrogen) partially explain phylogenetic and quantitative variances and indirectly influence bacterial assembly. We demonstrate a correlation-based statistical method to integrate bacterial association networks with their taxonomic affiliations to predict community-wide co-occurrence and co-exclusion patterns. The results show that although taxonomically closely related bacteria tend to positively co-occur (for example, out of a cooperative relationship), negative co-excluding correlations are deterministically observed between taxonomically less related species, probably implicating roles of competition in determining bacterial assembly. Overall, disclosures of the positive and negative species–species relations will improve our understanding of ecological niches occupied by unknown species and help to predict their biological functions in ecosystems.
Peter C. Pollard
Water Environment Research · 2006
Reliable design and operation of biological wastewater treatment systems demand robust models of biological degradation processes. However, methods to directly measure key bacterial growth kinetics have not been readily available. Those methods that are available rely on the classic measurement of aerobic respiration using oxygen uptake take rates. This paper shows how the thymidine assay can be used as a rapid and direct measurement of bacterial specific growth rates (μ) in situ for an anaerobic treatment process, independent of aerobic respiration. A filtration‐based assay is applied and evaluated a dispersed‐phase high‐rate anaerobic treatment process, with results obtained in less than an hour. The chemical oxygen demand (COD) biomass in the reactor was 0.52 kg COD m −3 and the specific growth rate of these anaerobic bacteria was 0.8 ± 0.2 d −1 . It took the bacterial populations 21.6 hours to double. This is an important advancement from existing methods that use aerobic respiration as a pseudo measurement of bacterial specific growth rates. The method allows rapid and direct measures of microbial growth rates for anaerobic treatment processes. Water Environ. Res. ,
Senthilkumar Sivaprakasam, Surianarayanan Mahadevan, Sudharshan Sekar et al.
Microbial Cell Factories · 2008
Abstract Background High salinity (1–10% w/v) of tannery wastewater makes it difficult to be treated by conventional biological treatment. Salt tolerant microbes can adapt to these saline conditions and degrade the organics in saline wastewater. Results Four salt tolerant bacterial strains isolated from marine and tannery saline wastewater samples were identified as Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and Staphylococcus aureus . Growth factors of the identified strains were optimized. Tannery saline wastewater obtained from a Common Effluent Treatment Plant (CETP) near Chennai (southern India) was treated with pure and mixed consortia of four salt tolerant bacterial strains. Experiments with optimized conditions and varying salt content (between 2 and 10% (w/v) were conducted. Salt inhibition effects on COD removal rate were noted. Comparative analysis was made by treating the tannery saline wastewater with activated sludge obtained from CETP and with natural habitat microbes present in raw tannery saline wastewater. Conclusion Salt tolerant bacterial mixed consortia showed appreciable biodegradation at all saline concentrations (2%, 4%, 6%, 8% and 10% w/v) with 80% COD reduction in particular at 8% salinity level the consortia could be used as suitable working cultures for tannery saline wastewater treatment.
Suhuttaya Jiranuntipon
· 2008
Distillery effluent from sugarcane molasses leads to an environmental pollution due to its large volume and the presence of dark brown colored compounds, known as melanoidins. In this study, a bacterial consortium CONS8 isolated from waterfall sediments in Maehongsorn province was selected as a molasses-decolorizing consortium. Consortium CONS8 was able to decolorize, only within 2 days, in Erlenmeyer flasks, three different synthetic wastewaters containing either Viandox sauce (13.5% v/v), beet molasses wastewater (41.5% v/v) or sugarcane molasses wastewater (20% v/v) at 9.5, 8.0 and 17.5%, respectively. Four predominant bacteria present in the consortium CONS8 were identified by the 16S rDNA analysis. To achieve the highest decolorization, the artificial bacterial consortium MMP1 comprising Klebsiella oxytoca, Serratia mercescens (T2) and unknown bacterium DQ817737 (T4), was constructed. Under optimized conditions (aeration, pH), the bacterial consortium MMP1 was able to decolorize the synthetic melanoidins-containing wastewater at 18.3% within 2 days. The comparison of decolorization by the consortium MMP1 with abiotic control proved that the color removal for synthetic melanoidins-containing wastewater medium was mainly due to biotic activity of bacterial cells, without any adsorption phenomena. Supplement of nutrients and vitamin B did not promote melanoidins decolorization by bacterial consortium MMP1. Finally, the performance of a membrane bioreactor (MBR) for synthetic melanoidins-containing wastewater treatment was investigated at laboratory scale, with a mineral membrane. The reactor seeding was made with the MMP1 bacterial consortium inoculum. The reactor was performed with several hydraulic retention times (HRT) of 15, 20, and 40 hours. The performances were analyzed in terms of COD, color removal and biomass in the reactor. The results indicated that the higher COD and color removal efficiency were achieved with the longer HRT.
Melody Johnson
· 2024
This work presents a comprehensive assessment of the environmental impact of winery wastewater (WWW) and methods to optimize its co-treatment at municipal wastewater treatment plants (WWTPs). A comprehensive review of full-scale treatment at 53 wineries in Niagara Region, Canada finds constructed wetlands are the most common type of on-site treatment. On-site systems do not address all treatment needs, requiring a portion of the WWW to be co-treated at WWTPs. From freshwater resource impact perspective, the grey water footprint (WF) associated with treated WWW effluents is often neglected from wine-making WF assessments. However, co-treated WWW effluents from WWTPs in Niagara Region are found to exert a substantial grey WF equivalent to over 960 times their volume. While full-scale operating data indicate that anaerobic co-digestion with municipal sludges is effective (89% chemical oxygen demand (COD) removal), co-digestion capacity is limited. Bench-scale co-treatment trials confirm that WWTPs’ aerobic activated sludge systems can effectively co-treat WWW provided organic loading rates are limited. A combined Michaelis-Menten-University of Cape Town kinetic model is found to best describe the pH-inhibited oxidation by heterotrophs, and the associated specific rate of substrate consumption is highest in biomass that had been exposed to WWW (57.3 mg COD/g MLVSS·h) compared to biomass that had not (20.7 mg COD/g MLVSS·h). The feasibility of using the Fenton-like process to pre-treat WWW to enhance co-treatment is assessed. Solubilization of particulate COD and total organic carbon (TOC), and sample handling requirements prior to analysis, are identified as factors affecting their apparent removal rates. Inert suspended solids generated during sample handling is found to be the variable best suited to quantifying the extent of reaction. However, the Fenton-like process provides limited opportunity to optimize co-treatment at WWTPs. A novel pre-treatment method, the Waste Activated Sludge-High Rate (WASHR) process, is proposed to optimize the co-treatment. The WASHR process combines the contact stabilization and sequencing batch reactor processes. It utilizes waste activated sludge from the WWTP as its biomass source, allowing rapid start-up. Bench-scale trials confirm that the WASHR process, vs. direct co-treatment, can reduce COD and total suspended solids loadings to the WWTP’s liquid treatment train by more than 81% and 92%, respectively, and to the solids treatment train by more than 59% and 30%, respectively. A case study is used to confirm the economic viability and environmental sustainability of the WASHR process compared with direct co-treatment. Finally, robust correlations between easily measured parameters and key organic and nutrient parameters are developed. The correlations provide a promising, rapid and cost-effective means of characterising WWW to allow improved process control.
M. Arnaldos, K. R. Pagilla
Water Science and Technology · 2015
The paper presents research on hemoglobin (Hb)-expressing bacteria in biological wastewater treatment systems. The outcome(s) will greatly reduce the aeration needs of wastewater treatment plants (WWTPs) and provide insight into emerging biological nitrogen removal processes using low dissolved oxygen (DO) conditions. In anthropogenic terms, the bacteria that express Hb could be considered as ‘bacterial sherpas’ that can function under low DO conditions. Hitherto, this functionality of bacteria has not been realized due to the initial response of the aerobic treatment stage: namely, morphology change by bacteria to filamentous forms to overcome oxygen mass transfer limitations causing bulking/foaming and nitrification inhibition. There is evidence, however, of the potential expression of Hb proteins by activated sludge (AS) bacteria. First, bacteria known to possess genes coding Hb proteins have been isolated from AS systems. Secondly, there is evidence that WWTPs are able to operate their biological processes at low DO without sludge bulking or incomplete nitrification. Our research has focused on nitrifying systems and has shown that this is due to prolonged operation at low DO conditions (0.1 mg O2/L), which allows sufficient time for bacterial acclimation. Additionally, it has been shown that enhanced Hb expression is linked to acclimation to low DO conditions.
Ashita Rai, Virendra Kumar Yadav, Daoud Ali et al.
Environmental Research Communications · 2024
Abstract Common Effluent Treatment Plant (CETP) wastewater poses significant environmental and health risks, necessitating advanced treatment technologies to meet discharge standards. This study focuses on the collection and characterisation of wastewater from CETP Vatva, Ahmedabad, to evaluate physicochemical parameters heavy metal concentrations, and identify indigenous bacterial species. Using Taguchi’s systematic orthogonal array, an effective indigenous bacterial consortium (EIBC) was created for bioreactor-based CETP wastewater treatment. The 16S rDNA analysis revealed the presence of various bacterial strains, including the newly reclassified bacteria Stutzerimonas stutzeri. The analysis of the SI sample indicated substantial reductions in the concentrations of total dissolved solids (1090 mg L −1 ), biological oxygen demand (28 mg l −1 ), chemical oxygen demand (180 mg l −1 ), and total phosphorus (1.4 mg l −1 ) compared to their initial values of 7504 mg l −1 , 29 6 mg l −1 , 58 8 mg l −1 , and 3.04 mg l −1 , respectively, with a similar trend observed in samples SII and SIII. While turbidity was significantly reduced from initial concentrations ranging between 36–42 NTU to 4 NTU in SI, 5 NTU in SII, and 3 NTU in SIII samples, resulting in clear water, odour remained a persistent concern throughout the study. Heavy metal concentrations were within permissible discharge limits, with notable removal rates for Cu, Fe, and Cd. The study concludes that integrating systematic design modelling with bioreactor-based remediation effectively mitigates water pollution and safeguards human well-being.
Ahmad Hussaini Jagaba
ChemBioEng Reviews · 2025
Abstract Bacterial granular sludge (BGS) process is currently believed to be feasible biological technique for wastewater treatment. However, several shortcomings have been identified. Hence, it became critical to employ environment‐friendly microalgae in the granulation process. The microalgal‐bacterial granular sludge (M‐BGS) technique for nutrient removal relies mostly on microbial absorption. The peculiar shape of M‐BGS can give rise to improved separation among sludge and treated wastewater. Hence, this article provides a review of the literature on the several developments in the applications microalgae for aerobic granulation and wastewater treatment. The review emphasized the current state of M‐BGS use for wastewater treatment and discussed the effects of physical, environmental, operational, and microbiological factors on M‐BGS system. The review identified inhibitory effect of various xenobiotic compounds that could induce decoupling of symbiosis in M‐BGS systems. M‐BGS has proven to be effective as it provides ecologically beneficial and sustainable remedies for the challenges faced during wastewater treatment.
Philips O Akinwole, Amerti Guta, Madeline Draper et al.
Research Square · 2021
Abstract The effluents of wastewater treatment plants (WWTPs) represent a complex mixture of nutrients and toxic substances, thus, the potential exists for the effluents to significantly impact the biochemical characteristics and bacterial communities of the receiving water. We examined spatial and seasonal patterns, and the impact of effluents on microbial biomass, bacterial community structure, and metabolic diversity on a fourth-order stream. We took triplicate sediment samples at five different locations along a 5,000m transect over three sampling periods. We quantified bacterial community structure as community-level physiological profiles and biomass with phospholipid phosphate analysis. Our findings highlight the worrisome impacts of effluents on microbial biomass and bacterial metabolic diversity on the receiving water. Microbial biomass was significantly higher at the WWTP outfall compared to upstream and downstream sites and correlated positively with sediment physicochemical parameters. Furthermore, our data revealed significant spatial differences in bacterial community structure in the context of WWTP impact. High nutrient availability (lower carbon/nitrogen ratios) at the outfall increased site-specific bacterial metabolic diversity in winter but decreased the same in fall. Seasonal changes in the sedimentary microbial biomass and bacterial carbon substrate utilization were evident regardless of the spatial variations or impacts of the wastewater effluents. Communities in fall showed more versatile substrate utilization patterns than the winter communities. These results suggest that WWTP effluents significantly increased microbial biomass and highlight its mixed effects on bacterial community structure and metabolic diversity. Also, our data underscore a close association between sedimentary physicochemical parameters and the associated microbial functional activities.
Nilesh Sonune, Anil Garode
Current World Environment · 2015
The potential of bacteria for the treatment of municipal wastewater was investigated in present study. Total eight bacterial isolates were used for this study that showed growth on wastewater agar medium. These isolates were identified on the basis of morphological and biochemical test and identified as Bacillus licheniformis NW16, Pseudomonas aeruginosa NS19, Pseudomonas sp. NS20, Planococcus salinarum NS23, Stenotrophomonas maltophilia NS21, Paenibacillus sp. NW9, Paenibacillus borealis NS3 and Aeromonas hydrophilia NS17. The B. licheniformis NW16 showed highest potential to reduce all parameter under study than other isolates except Ammonical nitrogen. B. licheniformis NW16 and Aeromonas hydrophilia NS17 showed maximum reduction (42.86%) in BOD each. B. licheniformis NW16 and Paenibacillus sp. NW9 showed 82.76% and 81.61% reduction in COD respectively. B. licheniformis NW16, P. salinarum NS23 and Aeromonas hydrophilia NS17 showed reduction in nitrate ranging from 17.36%-63.64%. All the isolates have potential to reduced phosphate from 17.55% -72.3%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, Paenibacillus sp. NW9 and Aeromonas hydrophilia NS17 showed reduction in TSS ranging from 42.69%-79.94%. B. licheniformis NW16, Ps. aeruginosa NS19, Pseudomonas sp. NS20, S. maltophilia NS21 and Paenibacillus sp. NW9 showed reduction in TDS ranging from 14%-81.4%.
Luz Chacon, Keilor Rojas-Jimenez, Maria Arias-Andres
bioRxiv (Cold Spring Harbor Laboratory) · 2023
Abstract Benzalkonium chloride (BAC) is a quaternary ammonium compound (QAC) widely used as the active ingredient of disinfectants. Its excessive discharge in wastewater is constant and in high concentrations, likely affecting the physiology of microbial communities. We compared the community physiological profile of activated sludge bacteria with and without in vitro previous exposure to a high concentration of BAC (10 mg/L). We measured the community functional diversity (FD), carbon substrate multifunctionality (MF), and the median effective concentration that inhibits carbon respiration (EC 50 ) using Biolog® EcoPlatesTM supplemented with a gradient of 0 to 50 mg/L of BAC. Surprisingly, we did not find significant differences in the physiological parameters between treatments. Certain abundant bacteria, including Pseudomonas, could explain the community’s tolerance to high concentrations of BAC. We suggest that bacterial communities in wastewater treatment facilities’ activated sludge (AS) are “naturally” adapted to BAC due to frequent and high-dose exposure. We highlight the need to understand better the effects of QACs in wastewater, their impact on the selection of tolerant groups, and the alteration in community metabolic profiles.
Manjiri Patil, Pranav Kshirsagar, Prashant Dhakephalkar et al.
Research Square · 2025
Abstract The dairy industry generates wastewater characterized by organic components, predominantly composed of proteins and fats, which can be effectively treated through biological processes. The present study aimed to develop a bacterial consortium for bioaugmentation to enhance the treatment of simulated dairy wastewater. A total of 75 bacterial isolates were obtained using Direct Isolation (DI) and Enrichment Isolation (EI) methods. Among these, four strains exhibiting the highest proteolytic and lipolytic activities within 24 hours were selected for further investigation. The isolates were screened based on their extracellular enzyme activities (proteinase and lipase), as well as their maximum lipolytic (0.3–0.7 mm/h) and proteolytic activity (0.67–0.83 mm/h) by a novel approach of rate of diffusion on Tributyrin Agar (TA) and Modified Skimmed Milk Agar (MSMA), respectively. The selected strains were identified by 16S rRNA gene sequencing as Massilia haematophila (DSSC1) , Brevibacillus agri (ENAT1) , Pseudomonas guguanensis (ENOG5) , and Lysinibacillus fusiformis (ETOG2 ) . The biodegradation potential of individual strains and their consortium was assessed through Chemical Oxygen Demand (COD) reduction in simulated dairy wastewater. The individual bacterial strains achieved COD reductions from an initial concentration of 3815 mg/L to 2950, 2813, 2480, and 2893 mg/L. In contrast, bioaugmentation with the bacterial consortia reduced COD to 2190 mg/L, resulting in a 26–86% higher reduction compared to the individual strains. This study presents the first report on the use of a novel approach of diffusion-based assay to develop an effective and innovative bacterial consortium for efficient dairy wastewater treatment. These findings highlight the potential of this approach towards enhancing biodegradation efficiency and advancing sustainable wastewater management practice.
Hossam Abdel Rahman
· 2021
The activated sludge process in Wastewater Treatment Plant (WWTPs) relies on the activities of microbes to reduce the organic and inorganic matter and produce effluent that is safe to discharge into receiving waters. This research examined the effects of non-steroidal antiinflammatory drug (NSAID) ibuprofen and the antibiotic tetracycline on the microbial population in activated sludge from the Humber WWTP. The current investigation was designated to observe the impact of these contaminants, at low (environmentally relative concentrations) as well as extremely high concentrations of tetracycline and ibuprofen. Using 16S and 18S rRNA gene primer sets, and qPCR the abundance of each population was monitored as well as the relative abundance of two populations under the various conditions. It was found that current environmental concentrations of ibuprofen stimulated protozoan growth but higher concentrations reduced their numbers especially in the presence of tetracycline. Finally using DGGE, the identity for some of the more abundant protozoa were identified and it was noted that high ibuprofen and tetracycline concentrations favored the abundance of some genera.
Christopher J.O. Baker, Roberta R. Fulthorpe, Kimberley Gilbride
· 2023
<p>The DNA fingerprinting techniques, 16S-restriction fragment length polymorphism (16S-RFLP), ribosomal intergenic spacer analysis (RISA) and repetitive extragenic palindrome PCR (Rep-PCR), were used for analyzing the bacterial communities of seven pulp and paper wastewater treatment systems. All three methods generate DNA fingerprints that can be compared using the computerassisted program, Gelcompar©. Community similarity coefficients were based on quantitative determinations of both the positions of the DNAbands and the band intensities in order to compare the relative differences in the populations. Unique 16S-RFLP DNA fingerprints were observed for each mill suggesting that individual mills contained phylogenetically different communities. However this method was not sensitive enough to detect differences within a mill treatment system from different locations or from different sampling times. The RISA method, which generated more complex fingerprints than 16S-RFLP, could, for some mills, discern differences between samples. The Rep-PCR technique, however, showed the highest degree of resolution and produced not only distinct patterns for each mill but also distinct fingerprints for the temporal and spatial samples from some of the treatment systems. The sensitivity of this method might potentially be used to monitor the stability of the bacterial community within a secondary treatment system.</p> <p><br></p>
Mauricio Barrera
· 2021
The reduction and degradation of total organic carbon (TOC) and bacteria inactivation efficiency using Vacuum-Ultraviolet (VUV) oxidation process Ultraviolet-C (UV-C) photolytic process, and their combination (UV-C/VUV and VUV/UV-C) from synthetic slaughterhouse wastewater was investigated. TOC removal rates achieved during continuous mode operation were 6.2%, 5.5%, 5.8%, and 6.1%, respectively. In a second stage, H₂O₂ was added to both processes, UV-C/H₂O₂ and VUV/H₂O₂, and it was found that TOC removal rates were increased twice as much during continious flow operation to 10.8% and 12.2%, respectively. The optimum molar ration of H₂O₂/TOC was found to be 2.5 and 1.5 for each process respectively. Finally, it was observed that all photochemical processes achieved over 99.999% (five logs) of bacteria inactivation in a short period of irradiation time, 27.6 sec.
Amir H. Tehrani, Kimberley Gilbride
· 2023
<p>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.</p> <p><br></p>
Κωνσταντίνος Παπαδόπουλος
· 2022
Η ανάπτυξη τεχνολογιών που επιτρέπουν την ανάκτηση ενέργειας και φυσικών πόρων είναι το κλειδί για την επίτευξη της βιωσιμότητας και της αποδοτικότητας στον τομέα της επεξεργασίας αποβλήτων. Η ενσωμάτωσή φωτοσυνθετικών μικροοργανισμών σε αερόβιες μικροβιακές κοινότητες μπορεί να αποτελέσει ένα βήμα προς αυτή την κατεύθυνση: η φωτοσύνθεση αντικαθιστά τον μηχανικό αερισμό του συστήματος, και οι φωτοσυνθετικοί μικροοργανισμοί καταναλώνουν τον παραγόμενο ανόργανο άνθρακα, μετατρέποντάς τον σε αξιοποιήσιμη βιομάζα. Η παρούσα εργασία επιχειρεί να αναπτύξει μια διεργασία που χρησιμοποιεί κοινότητες μικροφυκών-βακτηρίων για την επεξεργασία υγρών αποβλήτων, και μπορεί να αποτελέσει μία βιώσιμη εναλλακτική συμβατικών τεχνολογιών επεξεργασίας αποβλήτων.Χρησιμοποιώντας απόβλητα ζυθοποιίας ως σύστημα υπό μελέτη, αξιολογούνται δύο μικροβιακές κονότητες: (α) μία κοινότητα που απομονώθηκε από ενεργό ιλύ και (β) μία κοινότητα κυριαρχούμενη από το κυανοβακτήριο Arthrospira platensis. Παρόλο που και οι δύο κοινότητες επιβίωσαν στο απόβλητο, υψηλότεροι ρυθμοί ανάπτυξης, αφαίρεσης ρύπων, και ηπιότερες διακυμάνσεις στην σύσταση των μικροβιακών πληθυσμών παρατηρήθηκαν στην περίπτωση (α). Η ποικιλομορφία της μικροβιακής κοινότητας, τα μεταβολικά χαρακτηριστικά του κυανοβακτηρίου Leptolyngbya sp. που κυριάρχησε στις καλλιέργειες, και η συμβίωση με ετερότροφα βακτήρια επέτρεψε την αφαίρεση ανόργανων και οργανικών ρύπων, και τον σχηματισμό μεγάλων συσσωματωμάτων που μπορούν να διαχωριστούν με καθίζηση.Στη συνέχεια, αναπτύσσεται μια ημι-συνεχής διεργασία που αξιοποιεί τα χαρακτηριστικά των συσσωματωμάτων μικροφυκών-βακτηρίων. Οι στοιχειώδεις λειτουργικές αρχές της διεργασίας ενεργού ιλύος (καθίζηση και ανακυκλοφορία βιομάζας) διατηρούνται, ενώ ο αερισμός του συστήματος πραγματοποιείται αποκλειστικά μέσω της φωτοσύνθεσης. Τα αποτελέσματα υποδεικνύουν ότι η απόδοση της διεργασίας είναι σταθερή σε διαδοχικούς καλλιεργητικούς κύκλους, ενώ η ανακυκλοφορία της βιομάζας ευνοεί τον σχηματισμό μεγάλων συσσωματωμάτων που επιτρέπουν αποδοτικότερο διαχωρισμό βιομάζας και αφαίρεση ρύπων. Επιπλέον, η παραγωγή βιοαιθανόλης αξιολογείται ως στρατηγική αξιοποίησης της βιομάζας. Η παραγωγή βιοαιθανόλης, σε συνδυασμό με αποδοτική επεξεργασία αποβλήτων ζυθοποιίας αποδείχθηκε εφικτή, αλλά λιγότερο αποδοτική σε σχέση με συστήματα αποκλειστικά σχεδιασμένα για παραγωγή βιοκαυσίμων και συμβατικές τεχνολογίες παραγωγής βιοενέργειας, όπως η αναερόβια χώνευση.Τα πειραματικά αποτελέσματα προσεγγίστηκαν και αναλύθηκαν χρησιμοποιώντας μαθηματικά μοντέλα που αναπτύχθηκαν με το πακέτο ASM της IWA ως βάση και έμπνευση. Αποκαλύπτεται ότι η ένταση του φωτός και η σκίαση αποτελούν τους κύριους ρυθμιστικούς παράγοντες του συστήματος. Επιπλέον, υπογραμμίζεται περαιτέρω ο ρόλος της συσσωμάτωσης: δεν αποτελεί μόνο ένα μέσο διαχωρισμού της βιομάζας, αλλά επιτρέπει αποδοτικότερη διείσδυση της φωτεινής ακτινοβολίας σε πυκνές καλλιέργειας και προστατεύει τους μικροβιακούς πληθυσμούς από τη θήρευση. Το μοντέλο χρησιμοποιήθηκε επίσης για την εκτίμηση του λειτουργικού κόστους της διεργασίας σε μεγάλη κλίμακα. Αποδεικνύεται ότι ο συνδυασμός επεξεργασίας αποβλήτων με συσσωματώματα μικροφυκών-βακτηρίων και αξιοποίησης της βιομάζας με αναερόβια χώνευση μπορεί να εξαλείψει το λειτουργικό κόστος, αν και οι αυξημένες εδαφικές απαιτήσεις σε σχέση με άλλες συμβατικές τεχνολογίες πρέπει να ληφθούν υπόψιν.
Deniz Demirbilek, Ubeyde İpek, Ülkü Yetiş
Research Square · 2022
Abstract Activated sludge processes contains various groups of microorganisms with different metabolic properties, which are responsible for contaminants removal. Therefore, it is important to elucidate the general structure and functional properties of biomass in activated sludge processes. For this purpose, a full-scale domestic biological wastewater treatment plant in Tunceli (Turkey), Tunceli WWTP, was monitored to observe seasonal variations in process performance and biomass properties for a year. It was observed that nitrifying bacteria developed abundantly in the rainy and cool spring season as they were suppressed in summer because their large losses took placed due to an environment containing high alkalinity values. In September, aerobic heterotrophic, nitrify, denitrify, and anaerobic activities increased. It can be said that mature biomass contained young and active levels in an environment in which the sludge volume index (SVI) value increased to 196 mL/g. As a result of the improvement in the structural and functional properties of biomass, the nitrogen removal efficiency reached to 99%. Throughout whole study, the structural improvement observed in biomass reflected in its removal activity. The amount of biomass and removal activity decreased with the abundance of organic matter in the influent at the period in which biomass was closer to being categorized in the aged sludge class. The results showed that as the lowest mixed liquid volatile suspended solids (MLVSS) value of the year was 400 mg/L in November, MLVSS value reached the highest amount (1,400 mg/L) in December which aerobic heterotrophic activity accelerated with a decrease in organic matter level.
Ritesh Pattnaik, Lopamudra Ray, Koustav Saha et al.
Ammonia Oxidizing Bacteria · 2023
Although nitrogen fixation is essential for the continuation of life, excessive reactive nitrogen in surface and constructed water bodies as a consequence of limited tertiary wastewater treatment practices potentially harms the environment. At present, the majority of wastewater treatment units depend on various chemical approaches for the ready removal of reactive nitrogen species. However, because of both environmental and economic advantages, a significant shift towards the application of biological methods involving a specific group of microorganisms is under current emphasis. Excessive reactive nitrogen, besides having a negative impact on human health, also causes the pollution of water bodies triggering imbalances in aquatic ecosystems. Therefore, efficient strategies need to be adopted in order to remove excessive reactive nitrogen from different sources, including wastewater treatment plants. Globally, various technologies are in use to increase the efficacy of nitrogen removal treatment at an economic cost. The present chapter is aimed at outlining the different approaches for efficient nitrogen recovery and its multitude of sustainable applications.
Srishti Mishra, Brajesh K. Dubey, Makarand M. Ghangrekar
· 2025
The bioelectrochemical systems are sustainable solutions to face energy, water, and wastewater-related challenges. A three-chambered bioelectrochemical system, known as a microbial desalination cell (MDC), operates on the combined principles of a microbial fuel cell and electrodialysis. This self-powered system is capable of simultaneously treating wastewater and desalinating seawater. In the anodic compartment, microbial digestion of organic substrate treats wastewater. At the same time, the potential generation across the anode and cathode, resulting from electron production during the degradation process, leads to seawater desalination. Additionally, the oxygen reduction reaction (ORR) in the cathodic chamber significantly contributes to the overall performance of the system. Enhancing the ORR of the cell through catalyst incorporation has been shown to improve the system’s performance. The addition of a Sr-Mn-based perovskite, an abundant transition metal oxide compound, was synthesized using a facile method to be used as a cathode catalyst. The performance of the catalyzed reactor was compared to a non-catalyzed system with carbon electrodes. The addition of a catalyst resulted in a COD removal of 81.1 ± 0.5%, which was 35.5% higher than that recorded in the scenario without a catalyst. Similarly, in terms of desalination, the MDC with catalyzed cathode exhibited an 83.3 ± 1.2% desalination efficiency compared to the control MDC (45.76 ± 1.4%). This improved electrocatalytic performance of the system due to the catalyst was explained through the electrochemical analysis of the synthesized perovskite. The non-reliance of the MDC system on any external power source makes it a self-sustained and green technology for performing wastewater treatment and saltwater desalination, contributing to the Sustainable Development Goal 6 of clean water and sanitation.
Khaya Pearlman Shabangu, Babatunde Femi Bakare, Joseph Kapuku Bwapwa
Preprints.org · 2022
This study develops into the application of a combined MFC unit with chemical coagulation for total treatment of inert contaminants in complex substrates. Microbial Fuel Cell (MFC) technology converts chemical energy in the form of organic matter, into bioelectricity in an environmentally friendly and effi-cient manner, reducing carbon emissions and increasing bioenergy production. An evaluation of a la-boratory scale chemical coagulation using an aluminum and poly-based coagulant on how effective it can remove bulk impurities such as particulate COD and turbidity to obtain the purest and most cost-effectively treated wastewater using a jar test is being conducted in this current study. This study aims to find the most effective treatment technologies for wastewater recovery in breweries in order to achieve zero liquid effluent discharge (ZLED). The preliminary results showed that adding a modest amount of poly and a 50 % alum alone treatment improved COD, color, and turbidity reduction. The turbidity removal efficiency achieved after chemical coagulation treatment was 90.50 % and 59.36 % COD removal, demonstrating the benefits of adopting an alum/poly based technique. To determine ZLED, this study clearly advised a combined treatment technique, specifically the MFC-flocculator unit for efficient organics and inorganics removal.
Kiryl Hubchyk, Alena Hlushen, R. Birukou
5th International Scientific Conference on Microbial Biotechnology · 2022
Massive volumes of effluents discharged by the poultry-processing plants contain elevated levels of pollutants (dissolved keratins, blood, lipids and proteins), and are distinguished by high BOD and COD values, as well as by large concentrations of suspended particles [1]. Therefore, there is an urgent need to develop effective and eco-safe methods protecting the environment from contamination. Among such methods the application of efficient microbial degraders of toxicants, possessing enhanced flocculating and decomposing activity, that can be introduced into the decontamination units to supplement the microbiota of the activated sludge at various stages of treatment, seems to be especially promising. Currently, biopreparations of microbial consortia intended for remediation of the environments exposed to organic pollutants are widely spread. The most common constituents of such consortia represent such genera as Rhodococcus, Bacillus, Pseudomonas, Arthrobacter, etc. [2]. Our study was focused on the microorganisms of the Rhodococcus and Bacillus genera, which are able to utilize the organic compounds in the poultry processing wastewater. There were selected 14 variants out of 145 screened strains that were either deposited in the laboratory of environmental biotechnologies, Institute of Microbiology, NAS of Belarus, or isolated from effluents of poultry-processing plants. They were tested for the COD degradation activity in poultry-processing wastewater, assayed for the proteolytic and lipolytic activities [3], and estimated for the biosurfactant forming potential [4]. The degradation activity of the selected microbial cultures was investigated using poultry-processing effluents with initial COD value of 1144 O2/dm3. It was found that the top COD reduction was by B. subtilis 6/2-APF1, B. coagulans 1710, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1, R. ruber 30P, R. ruber 200N, R. ruber 1NG – 52,3-71,6%. The maximum proteolytic activity toward milk proteins was observed for B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5. The lipolytic activity on the tributyrin-containing medium was detected in all 14 tested strains – B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1, R. erythropolis 7D, R. erythropolis 23F, R. erythropolis 70F, R. ruber 2B, R. ruber 1NG, R. ruber 30P, Rhodococcus sp. P1, Rhodococcus sp. G13, R. ruber 200N with the last two being especially active. The highest capacity to produce biosurfactants in the specific nutrient medium with methylene blue was displayed by B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5. In addition, the ability to produce surface active agents was observed for the bacterial cultures of Bacillus sp. PF1, R. ruber 2B, Rhodococcus sp. R1-3FN, Rhodococcus sp. G13 and R. erythropolis 7D. Among the tested bacterial strains, the following cultures proved to be the most effective in decontamination of the poultry-processing wastewater: B. coagulans 1710, B. subtilis 6/2-APF1, Bacillus sp. FL-9MV, Bacillus sp. FL X-5, Bacillus sp. PF1. The above-listed microorganisms may act as promising components of the biopreparations promoting decontamination of the poultry-processing effluents.
Jerzy J. Ganczarczyk
Water Science and Technology · 1994
Basic forms of microbial aggregates generated in wastewater treatment and techniques used to study them, are described and discussed. The role of the free-setting velocity in evaluation of some physical properties of activated sludge flocs is emphasized. Several regression models were applied to correlate the flocs' settling velocity with flocs' size values. For the studied samples a simple linear model proved to be superior to a multiplicative one, and an introduction to this model of a settling shape factor function instead of constant intercepts, provided a very good correlation of the experimental data. It is expected that a difference between shape factors for the most stable conditions of the flocs and those for the flocs under the settling conditions will make it possible to determine softness or stiffness of these microbial aggregates.
Ιωάννης Σταυρακάκης
· 2025
Η παρούσα έρευνα εξετάζει καινοτόμες προσεγγίσεις για την ελαχιστοποίηση της περίσσειας ιλύος, με έμφαση στην εφαρμογή χημικών αποσυζευκτών και οζόνωσης σε συστήματα βιοαντιδραστήρων μεμβρανών (MBR). Οι χημικοί αποσυζευκτές, όπως η 3-χλωροφαινόλη (m-chlorophenol - mCP), η 4-νιτροφαινόλη (p-nitrophenol - pNP) κ.ά., έχει αποδειχθεί ότι μειώνουν αποτελεσματικά την περίσσεια ιλύος επηρεάζοντας την οξειδωτική φωσφορυλίωση, αποσυνδέοντας την παραγωγή ενέργειας από τη σύνθεση μικροβιακής βιομάζας. Αυτή η βιοχημική παρέμβαση όχι μόνο μειώνει την απόδοση της ενεργού ιλύος που παράγεται, αλλά επηρεάζει επίσης τα μικροβιακά μεταβολικά μονοπάτια, οδηγώντας στη προσαρμογή εξειδικευμένων μικροβιακών ομάδων και εντέλει σε αλλαγή της δομής της μικροβιακής κοινότητας. Η αλληλούχηση υψηλής απόδοσης γονιδίων 16S rRNA αποκάλυψε δυναμικές αλλαγές στον πληθυσμό βακτηρίων κατά την εφαρμογή των εξεταζόμενων χημικών αποσυζευκτών, επάγοντας σημαντικές επιπτώσεις στη μικροβιακή ποικιλότητα και στη μεταβολική δραστηριότητα της ιλύος. Η οζόνωση, μια συμπληρωματική χημική μέθοδος επεξεργασίας σε μονάδες επεξεργασίας υγρών αποβλήτων, περιλαμβάνει την εφαρμογή όζοντος στο μικτό υγρό, οδηγώντας στην οξειδωτική διάσπαση σύνθετων οργανικών ενώσεων. Η διαδικασία αυτή όχι μόνο ενισχύει τη βιοαποδομησιμότητα της ιλύος, οδηγώντας σε υψηλή μείωση της παραγόμενης ιλύος, αλλά συμβάλλει επίσης σε αλλαγή της δομής της μικροβιακής κοινότητας αναστέλλοντας επιλεκτικά ορισμένες ταξινομικές ομάδες βακτηρίων, ενώ προωθεί την ενίσχυση γενών ανθεκτικών στην οζόνωση. Μικροβιακές αναλύσεις έδειξαν ότι η προσθήκη οζονισμένης ιλύος μείωσε τις εξωκυτταρικές πολυμερείς ουσίες (Extracellular Polymeric Substances - EPS) και τα διαλυτά μικροβιακά προϊόντα (Soluble Microbial Products - SMP), που συμβάλλουν στο σχηματισμό βιοϋμενίου και στην έμφραξη της μεμβράνης. Ο συνδυασμός της οζόνωσης με την τεχνολογία MBR οδήγησε σε καλύτερη απόδοση επεξεργασίας διατηρώντας υψηλή ποιότητα εκροής, ενώ ελαχιστοποίησε την παραγόμενη περίσσεια βιοστερεών και τη μικροβιακή έμφραξη της μεμβράνης. Η υιοθέτηση αυτών των προσεγγίσεων βιοχημικής μηχανικής στην τεχνολογία MBR μπορεί να αντιμετωπίσει βασικές λειτουργικές προκλήσεις, όπως η έμφραξη των μεμβρανών των συστημάτων αυτών. Η παρακολούθηση των φυσικοχημικών παραμέτρων έπαιξε σημαντικό ρόλο στην αξιολόγηση της σταθερότητας και της απόδοσης του συστήματος MBR. Πραγματοποιήθηκε παρακολούθηση σε σταθερή βάση του διαλυμένου οξυγόνου (Dissolved Oxygen - DO), του χημικά απαιτούμενου οξυγόνου (Chemical Oxygen Demand - COD), του ολικού κατά Kjeldahl αζώτου (Total Kjeldahl Nitrogen - TKN) και του pH για τη βελτιστοποίηση των λειτουργικών παραμέτρων. Επιπλέον, η παρακολούθηση των συγκεντρώσεων EPS και SMP παρείχε χρήσιμες πληροφορίες για τυχόν έμφραξη της μεμβράνης και τη μεταβολική απόκριση του μικροβιακού πληθυσμού. Με τη βελτιστοποίηση της ηλικίας ιλύος (Sludge Retention Time - SRT) και τη εφαρμογή ελεγχόμενων επιπέδων διαλυμένου οξυγόνου, μεγιστοποιήθηκαν οι επιδόσεις του συστήματος MBR όσον αφορά την απομάκρυνση θρεπτικών ουσιών, την πρόληψη της βιολογικής έμφραξης της μεμβράνης και τη μείωση της παραγόμενης περίσσειας ιλύος. Η μείωση της διαμεμβρανικής πίεσης (Transmembrane Pressure - TMP) μετά την προσθήκη οζονισμένης ιλύος ανέδειξε τη θετική επίδραση της οξειδωτικής αυτής μεθόδου στην αντιμετώπιση της έμφραξης της μεμβράνης. Επιπλέον, η βελτιστοποίηση της ηλικίας ιλύος ενίσχυσε συνεργιστικά την αποτελεσματικότητα των εφαρμοζόμενων χημικών μεθόδων. Παρατηρήθηκε δραστική μείωση της συγκέντρωσης των βιοστερεών από 6500 mg/L και 5650 mg/L πριν από την προσθήκη pNP και mCP, σε 4070 mg/L και 3540 mg/L αμέσως μετά την προσθήκη αυτών των μεταβολικών αποσυζευκτών, η οποία συγκέντρωση βιοστερεών, ωστόσο, επανήλθε στις αρχικές τιμές μέσα σε διάστημα 10-12 ημερών, ενδεχομένως μέσω επιλεκτικής ανθεκτικότητας (ή/και μηχανισμούς αποδόμησης στην περίπτωση του pNP) ως τρόποι προσαρμογής στην παρουσία pNP και mCP. Η προσαρμογή αυτή υποδηλώνει ότι οι μικροβιακές κοινότητες της ιλύος προσαρμόστηκαν και εμφάνισαν ανθεκτικότητα κατά την έκθεση σε αυτούς τους μεταβολικούς αποσυζευκτές, παρατηρώντας ανάκαμψη στη σύνθεση της βιομάζας μετά από μια σύντομη περίοδο αναστολής. Η προσθήκη pNP δεν επηρέασε την απόδοση απομάκρυνσης COD (μέση απόδοση απομάκρυνσης COD ίση με 98% πριν και μετά την προσθήκη pNP), αν και η προσθήκη mCP οδήγησε σε σημαντική αύξηση της συγκέντρωσης COD τόσο στην εισροή όσο και στην εκροή του συστήματος, λόγω της πιο ανθεκτικής δομής αυτού του μορίου, το οποίο φαίνεται να ανθίσταται στη μικροβιακή διάσπαση σε σύγκριση με την pNP. Ωστόσο, κατά μέσο όρο 672 mg/L και 669 mg/L, καθώς και 847 mg/L και 642 mg/L COD πριν και μετά την προσθήκη αποζευκτή απομακρύνθηκαν στις περιπτώσεις της προσθήκης pNP και mCP αντίστοιχα, υποδεικνύοντας ότι η απομάκρυνση του COD του υπό επεξεργασία υγρού αποβλήτου (εξαιρουμένου του προστιθέμενου mCP) δεν επηρεάστηκε από την προσθήκη του αποζευκτή. Στην περίπτωση της pNP, η αποτελεσματικότητα απομάκρυνσης TKN και NH₄⁺-N μειώθηκε σημαντικά αμέσως μετά την προσθήκη του αποσυζευκτή, αν και με αντιστρεπτό τρόπο, καθώς οι νιτροποιητές αποκατέστησαν τη δραστηριότητα οξείδωσης της αμμωνίας μία εβδομάδα μετά την εφαρμογή της pNP. Όσον αφορά την προσθήκη mCP, σημειώθηκε εντονότερη αναστολή της νιτροποιητικής δραστηριότητας, αλλά επίσης με αντιστρεπτό τρόπο, μετά όμως από πιο παρατεταμένο χρονικό διάστημα. Όσον αφορά την προσθήκη pNP, παρατηρήθηκε μια αρχική μείωση των συγκεντρώσεων των πρωτεϊνικών SMP και EPS, η οποία σταδιακά σταθεροποιήθηκε, υποδεικνύοντας μικροβιακή διαταραχή που ακολουθήθηκε από προσαρμογή. Συγκριτικά, η προσθήκη mCP οδήγησε σε ακόμη πιο έντονη επίδραση στα εκλυόμενα SMP και EPS, ιδίως εκείνων πρωτεϊνικής φύσεως. Η προσθήκη pNP και mCP οδήγησε σε σημαντικές μεταβολές στη δομή των μικροβιακών κοινοτήτων, αν και αυτές διέφεραν σημαντικά ως προς την έκταση και τις μικροβιακές ομάδες που επηρεάστηκαν. Για την pNP, παρατηρήθηκαν μεταβολές κυρίως στη σχετική αφθονία των Bacteroidota (συν. Bacteroidetes), των Gammaproteobacteria και των Bacillota (συν. Firmicutes). Ειδικότερα, τα νιτροποιητικά βακτήρια διατήρησαν τη σχετική αφθονία τους, ακόμη και όταν η δραστηριότητά τους αναστάλθηκε προσωρινά. Η εκτίμηση της β-ποικιλότητας έδειξε σημαντική αλλαγή στη δομή της κοινότητας βακτηρίων μετά την προσθήκη pNP, γεγονός που αποδίδεται στην παροδική αναστολή που προκάλεσε η προσθήκη pNP. Γένη βακτηρίων που συμμετέχουν στην αποδόμηση της νιτροφαινόλης, όπως μέλη των γενών Clostridium, Cytophaga και Pseudomonas, ενισχύθηκαν μετά την προσθήκη pNP. Συγκριτικά, η προσθήκη mCP οδήγησε σε πιο έντονες αλλαγές στη μικροβιακή ποικιλότητα και δομή, όπως αποδεικνύεται από τη σημαντική μείωση των δεικτών βιοποικιλότητας. Επίσης, σημειώθηκε εντονότερη αναστολή των νιτροποιητών. Ειδικότερα, δεν ανιχνεύθηκαν μέλη των γενών Nitrosomonas και Nitrospira μετά την προσθήκη mCP, υποδεικνύοντας ότι η mCP προκάλεσε σοβαρή αναστολή στις ταξινομικές αυτές ομάδες βακτηρίων. Η προσθήκη mCP ευνόησε τα ανθεκτικά σε αυτήν γένη, όπως είναι μέλη των γενών Pseudomonas και Arcanobacterium, αναδεικνύοντας την επιλεκτική πίεση που ασκείται στις μικροβιακές κοινότητες της ενεργού ιλύος από την mCP, οδηγώντας στην επιβίωση και κυριαρχία των πιο ανθεκτικών στις χλωροφαινόλες, ταξινομικών ομάδων. Η οζόνωση οδήγησε στην οξειδωτική διάσπαση ανθεκτικών συστατικών της οργανικής ύλης, ενισχύοντας τη βιοαποδομησιμότητα της ιλύος και τη διάσπαση θρεπτικών συστατικών. Τα αποτελέσματα έδειξαν μείωση κατά 38% των εξωκυτταρικών πολυμερών ουσιών (EPS) και μείωση κατά 32% των διαλυτών μικροβιακών προϊόντων (SMP), βασικών παραγόντων που συμβάλλουν στο σχηματισμό βιοϋμενίου και στην έμφραξη της μεμβράνης. Ο συνδυασμός της οζόνωσης και της τεχνολογίας MBR βελτίωσε την απόδοση του συστήματος, επιτυγχάνοντας ποσοστά απομάκρυνσης COD και TKN άνω του 95%. Η οζόνωση της περίσσειας ιλύος και η επιστροφή της στον MBR τμηματικά επέτρεψε τη μείωση των βιοστερεών του μεικτού υγρού από μια μέγιστη τιμή 9,8 g/L πριν από την προσθήκη, σε μια μέση συγκέντρωση βιοστερεών 5,5 ± 0,2 g/L μετά την προσθήκη οζονισμένης ιλύος, διατηρώντας μια σταθερή συγκέντρωση βιοστερεών για παρατεταμένη χρονική περίοδο. Όσον αφορά την προσθήκη οζονισμένης ιλύος, τα κυρίαρχα φύλα στον MBR ήταν τα Pseudomonadota και Bacteroidota, ακολουθούμενα από τα Planctomycetota, Actinomycetota και Chloroflexota. Τα γένη Lewinella και Methylophilus ήταν κυρίαρχα πριν από την προσθήκη οζονισμένης ιλύος, ωστόσο, μετά την προσθήκη, εντός του φύλου Bacteroidota, παρατηρήθηκε σημαντική διαδοχή, με τα Aureliella, Flavobacterium και Chryseosolibacter να γίνονται κυρίαρχα, σε σχέση με τα Lewinella. Η ανάλυση β-ποικιλότητας αποκάλυψε μια σημαντική μετατόπιση στη δομή της κοινότητας βακτηρίων, η οποία σταθεροποιήθηκε εντός 10 ημερών μετά την τμηματική προσθήκη οζονισμένης ιλύος. Αξίζει να σημειωθεί ότι οι νιτροποιητικές κοινότητες παρέμειναν ανεπηρέαστες, γεγονός που υποδηλώνει ότι είναι ανθεκτικές σε μέτριες συγκεντρώσεις όζοντος. Τα ευρήματα αυτά υπογραμμίζουν τη δυνατότητα εφαρμογής χημικών αποσυζευκτών και τμηματικής προσθήκης οζονισμένης ιλύος για την προώθηση της τεχνολογίας MBR. Ο έλεγχος της βιοεπεξεργασίας σε συνδυασμό με τις γνώσεις που αποκτήθηκαν για τις μικροβιακές κοινότητες κατά την εφαρμογή των παραπάνω μεθόδων ελέγχου της περίσσειας ιλύος συνέβαλαν στην επίτευξη βελτιωμένης απόδοσης επεξεργασίας, μειωμένης παραγωγής βιοστερεών και βελτιωμένης σταθερότητας του συστήματος MBR, ανοίγοντας το δρόμο για πιο βιώσιμες και οικονομικά αποδοτικές λύσεις επεξεργασίας υγρών αποβλήτων.
GM Itheshamul Islam
· 2021
Nitrification is an essential microbial process in the global nitrogen cycle. The first step of nitrification is ammonia oxidation which is achieved by bacteria and archaea and is crucial in decreasing ammonia concentrations that are persistently high in wastewater. This study examined the composition, abundance and identity of the microbial community in activated sludge with a focus on characterizing ammonia oxidizing bacteria and archaea in a full-scale municipal wastewater treatment plant (MWTP). Specifically, two pharmaceutical compounds Tetracycline and Ibuprofen, and their effects on the community composition of bacteria and protozoa in activated sludge was investigated using PCR coupled with denaturing gradient gel electrophoresis (DGGE). In addition, the composition, abundance and activity of the ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) were analyzed from aerobic activated sludge, recycled sludge and anaerobic digesters of the Humber MWTP using molecular techniques such as PCR, Quantitative PCR, Reverse Transcription-PCR and DGGE. The findings demonstrated that Tetracycline did not appear to alter community composition of bacteria in the activated sludge, rather, the operational parameters of the sequencing batch reactors such as feeding rates and SRT have shown to alter the richness of bacterial communities. However, Ibuprofen affected some members in the protozoan community in activated sludge. In the full-scale Humber MWTP using the conventional activated sludge system, the aeration tanks contained 1.8 × 105 copies of the AOB amoA gene per 100 ng of DNA. In contrast, the anaerobic digester tanks contained 7.3 × 102 copies of the AOA amoA gene per 100ng of DNA. This study also found that AOB were dominant in activated sludge samples, regardless of the operational parameters. The quantification of cDNA transcripts of the amoA gene also indicated that AOB may be more active than AOA in the activated sludge system. Overall, it appears that AOA are very niche specific and thrive in very low oxygenated environments, while AOB proliferate and play a major role in aerobic ammonia oxidation occurring in MWTPs.