Biological Water Treatment Research Articles

Immobilization of microbial cells for the biotreatment of wastewater: A review

Industrial wastewater often contains different complex impurities that are hazardous to the environment and human health, making wastewater treatment a necessity prior to its disposal. This review focuses on cell immobilization in the biological wastewater treatment, in which microorganisms are utilized for the biodegradation and removal of different types of contaminants, depending on the type of contaminat. Cell immobilization provides the ability to successfully limit the mobility of the cells using synthetic or natural polymers, which can then be used as biocatalysts instead of free cells. We provide a comprehensive evaluation of major cells immobilization aspects, starting from the definition of the technology and focusing on a critical and technical analysis of the currently used immobilization techniques including adsorption, covalent binding, entrapment and encapsulation. Biological water treatment systems using immobilized cells have the potential to be utilized in the degradation of various types of wastewater contaminants. This resulted in remarkable advances in the immobilization techniques, used materials, and properties of immobilized systems. Cell immobilization techniques are becoming well developed, new techniques are being studied by researchers, and the trend of advances in this area is expected to continue increasing in the coming years. Studies proved that immobilization is an effective and promising technique to enhance biological wastewater treatment processes. Immobilized cells could increase the removal efficiency of water contaminants, particularly nutrients, by more than 60%. In this review, the main factors in the development of immobilized cells are highlighted, starting from the selection of immobilization support and providing a detailed description of the immobilization techniques. The application of cells immobilization for different wastewater treatment processes is illustrated. Different examples of wastewater biotreatment are presented, including refractory organics wastewater, wastewater containing heavy metal ions, nitrogen and phosphorous wastewater as well as the removal of dye and color in textile industry wastewater. The review ends with a brief overview of future perspectives of research on cells immobilization.

Degradation kinetics, mechanism and toxicology of tris(2-chloroethyl) phosphate with 185 nm vacuum ultraviolet

Organophosphorus esters (OPEs), a series of high production volume chemicals, receive increasing concerns due to their occurrence in worldwide aquatic environment and resistance to conventional biological water treatment processes. Degradation of tris(2-chloroethyl) phosphate (TCEP) was tested with 185 + 254 nm ultraviolet irradiation treatment. Transformation of TCEP followed a pseudo-first order kinetics with an apparent rate constant at 1.65 × 10−3 s−1 when [TCEP]0 = 3.51 μM, 185 vacuum ultraviolet (VUV) irradiation intensity = 0.24 mW cm−2. Degradation experiments with wavelength screening, radical scavenging and kinetic calculation revealed that the radical-based oxidation induced by 185 nm VUV was the dominant mechanism with a reaction rate constant kOH-TCEP at (3.2 ± 0.3) × 108 M−1 s−1. Radical-based addition and substitution of TCEP generated intermediate products with phosphate backbone at early stage (0–20 min). Based on the toxicology analysis including reactive oxygen species and apoptosis of Escherichia coli, these early stage products have lower toxicity than TCEP or their further small molecule products. Variable pH value and natural organic matters/anions affected the efficiency of VUV, while intrinsic VUV screening and radicals scavenging were two key inhibition mechanisms. VUV induced a radical-based oxidation of TCEP, and it will be a promising treatment method for transforming and detoxifying micro-pollutants from water.

The Rationale for the Fish Farms Circulating Water Biological Treatment Intensification

Aerobic biological treatment of waters in artificial conditions is carried out by symbiotic algobacterial community of attached and free-floating organisms in various types of aerotank and biofilters. With the blowers and mixers of different designs, the biomass is saturated with oxygen. Controlled air supply provides the necessary concentration of dissolved oxygen and stimulates the oxidation of organic and inorganic water pollutants symbiotic community.

Effects of pH on biological treatment of paper mill white water with the addition of dominant bacteria

Virgibacillus pantothenticus, Bacillus cereus, and B. subtilis were screened from an activated sludge that had become acclimated to white water in the laboratory. The effects of the pH on the ability of biological treatment to reduce the biological oxygen demand of white water was studied for three dominant bacteria. The pH ranged from 4 to 8, and the optimum treatment efficiencies for white water treatments with the single dominant bacterium V. pantothenticus, B. cereus, and B. subtilis occurred at pH values of 5, 6, and 6, respectively. The results also indicated that the best treatment effect was achieved at a hydraulic retention time of 14 h. When each dominate species was tested under their optimum pH value and hydraulic retention time, the chemical oxygen demand removal rate was 67.7%, 77%, and 75.4%; the electrical conductivity decreased by 0.18 mS/cm, 0.93 mS/cm, and 0.51 mS/cm; and the cationic demand decreased by 69.7%, 70.0%, and 70.9% for V. pantothenticus, B. cereus, and B. subtilis, respectively. These results are helpful for promoting the practical application of dominant bacteria in white water treatment.

АНАЛІЗ ЕФЕКТИВНОСТІ ЗАСТОСУВАННЯ РОТОРНИХ АЕРАТОРІВ ПРИ ОЧИЩЕННІ ВОДИ У СИСТЕМАХ З ОБОРОТНИМ ВОДОПОСТАЧАННЯМ

Purpose of the research is to substantiate the feasibility of rotary type aerators usage at biological water treatment plants with recirculation

Effect of salinity in heterotrophic nitrification/aerobic denitrification performed by acclimated microbiota from oil-produced water biological treatment system

Mixed cultures salt acclimated showed high efficiency in heterotrophic nitrification/aerobic denitrification process in hypersaline conditions. They were able to remove 80% of ammonium in Heterotrophic Nitrification Medium (HNM) with 12 and 14% of salt. Above these salinity, the process still had 40% ammonium removal up to 20% of salt. Chromatography analysis validated the occurrence of the heterotrophic nitrification/aerobic denitrification process in all studied salinities (6%–20% of NaCl). However, with increasing salinity, the N2 production was smaller and took longer than the unsalted control. Microbial diversity analysis of mixed cultures showed that different groups of nitrifying microorganisms were involved in ammonium removal, including heterotrophic nitrifying/aerobic denitrifying genera such as Pseudomonas, Paracoccus, Bacillus, Halomonas, Acinetobacter and Klebsiella. In addition, this analysis also revealed that the acclimation process allowed the adaptation of the microorganisms to high saline conditions and ammonium removal up to 20% of salt. This work showed that heterotrophic nitrification/aerobic denitrification process could occur in high salinity after microbiota acclimation step, and these mixed acclimated cultures have a potential for application in hypersaline effluent treatment.

Using Myriophyllum aquaticum (Vell.) Verdc. to remove heavy metals from contaminated water: Better dead or alive?

This study aimed to investigate the potential of the invasive macrophyte Myriophyllum aquaticum to remove heavy metals. The elements tested were Cd, Cr, Ni, and Zn, in single-metal trials, and experiments were performed with both the living and dead biomass of the plant.In respect of metal removal by living plants, the element that was removed the most was Zn, though Cd showed the highest concentration in plant shoots. The metal negative effect on plant growth was, therefore, more important than the level of metal concentration in plant tissue in determining the removal percentages. All the metals were mostly accumulated in the roots, where a considerable fraction of the element was simply adsorbed to root cell wall, except in the case of Cr. In shoots, the fraction of the adsorbed metal was extremely low in respect to roots, thereby implying a lower apoplastic binding capacity.As regards a possible use of the dead biomass for metal removal, we proposed the generation of a hybrid biosorbent enclosing the dried and grounded plant biomass in cotton bags to improve its handling and its adsorption capacity, in view of a valid alternative to reduce the problems of packed beds. Cadmium—and especially Zn—were the elements removed most efficiently with respect to the other metals.On comparing the removal percentages of the living biomass and the hybrid biosorbent, our data deposed in favour of the use of M. aquaticum as dead biomass for a possible application of this invasive macrophyte in the biological treatment of metal-contaminated water. Our findings may be beneficial to metal removal application accompanying wetland management, devising a possible use of M. aquaticum waste material after its removal from the invaded habitats.

Microbial electrolytic disinfection process for highly efficient Escherichia coli inactivation

Water quality deterioration caused by a wide variety of recalcitrant organics and pathogenic microorganisms has become a serious concern worldwide. Bio-electro-Fenton systems have been considered as cost-effective and highly efficient water treatment platform technology. While it has been extensively studied for recalcitrant organics removal, its application potential towards water disinfection (e.g., inactivation of pathogens) is still unknown. This study investigated the inactivation of Escherichia coli in a microbial electrolysis cell based bio-electro-Fenton system (renamed as microbial electrolytic-Fenton cell) with the aim to broad the application of microbial electrochemistry. Results showed that a 4-log reduction of Escherichia coli (107 to hundreds CFU/mL) was achieved with an external applied voltage of 0.2 V, 0.3 mM Fe2+ and cathodic pH of 3.0. However, non-notable inactivation was observed in the control experiments without external voltage or Fe2+ dose. The disinfection effect was enhanced when cathode air flow rate increased from 7 to 41 mL/min and was also in proportion to the increase of Fe2+ concentration from 0.15 to 0.45 mmol/mL. Fatal cell membrane destruction by OH was identified as one potential mechanism for disinfection. This study successfully demonstrated the feasibility of bio-electro-Fenton process for pathogens inactivation, which offers insight for the future development of sustainable, efficient, and cost-effective biological water treatment technology.

Design and Optimisation of Home Scale Greywater Recycling Package

Water crisis is becoming one of the biggest challenges in some countries due to over population and drought. Therefore, government and non-government organisations in well-developed countries are encouraging industries to install water recycling package to reduce water usage and consume greywater instead. However the home scale is not yet available in the market. This research focuses on design a home scale greywater treatment system for toilet flushing within 3,000 to 5,000 USD as a collaboration with DD Techniche Sdn Bhd. Greywater is the waste water produced from laundry, kitchen and bathroom except the toilet waste and contains suspended solids, microorganisms, oil, nitrates and phosphorus which needs to be treated using suitable types of treatment for safe reuse. The treatments include physical, chemical and biological water treatment in which in this study the proposed system is a combination of all three. The design is evaluated using experimental methods to meet the standard of toilet flushing quality. The greywater system consists of the mechanical parts to control the flow of greywater and store the treated water including pumps, sand filtration tank, wire mesh chassis and collection tank. The final design has dimension of 6 m3 and optimised price within the budget.

Can Induced Magnetic Field Enhance Bioprocesses? - Review

This review presents a compilation of works with particular interest in the application of static magnetic field (SMF) to biological systems, wastewater treatment and few available reports on microbial granulation technology. It also highlights the effects of SMF on biological systems and wastewater treatment process. With an increasing need for environmentally conscious solutions to water purification and disinfection, wastewater treatment, bioremediation and other cheap alternative means, the application of SMF in biological water and wastewater treatment without increase in chemicals required may become an attractive option. Application of SMF has been reported to be successful in a number of fields including treatment of wastewater. However, there are sparse reports on SMF application in the formation and development of microbial granule and production of extracellular polymeric substances (EPS). Achieving a short start-up time in a bioreactor towards the development of microbial granule is of paramount importance in granulation technology. Ascertaining how effective varying strength of SMF and other input variables may enhance the microbial granule with respect to its physical, chemical and biological characteristics requires further research.

Biological Treatment of Real Oilfield-Produced Water by Bioaugmentation with Sophorolipid-Producing Candida catenulata

This study focuses on biological removals of petroleum hydrocarbons from an oilfield-produced water generated in Naft Shahr resource by natural attenuation, biostimulation, and bioaugmentation processes. The results of the natural attenuation experiments indicated low population of existing environmental bacterial cells which could not remove total petroleum hydrocarbon (TPH) and initial chemical oxygen demand (COD) at 30 °C and 180 rpm. However, biostimulation by adding nitrogen, sulfur, and phosphorus sources resulted to 19.9% removal of TPH, mainly corresponding to the low chain n-alkanes, and 15.9% removal of COD in 6 days. Degradation of hydrocarbons with longer chain than C20 was limited mainly due to the low solubility of the hydrophobic compounds in the process. Bioaugmentation with the locally-isolated biosurfactant-producing Candida catenulata provided a companionship of the yeast with existing bacterial environmental cells and resulted in increase of the biodegradability of TPH by 16.1% even in the absence of the additional nutrient. A uniform degradation for all hydrocarbon fractions was only observed in the combination of biostimulation with bioaugmentation processes. The study on initial pH yielded the highest removals of 93.39% of TPH and 66.85% of COD in the combined process when initial pH was set at 5.0.

Study of chloride concentration of Nira River, Pune, Maharashtra, India.

The present work deals with the study of Chloride concentration of Nira River in the year 2016. Fresh water is essential to existence of life. Acceptable quality water is essential not only for drinking and domestic purposes but also for agriculture, industrial and commercial uses. Chloride occurs naturally in all types of water. In natural fresh water, the concentration is quite low. The important source of chloride in the water is the discharge of domestic sewage. Chlorides are highly soluble in water so they do not get precipitate and cannot be removed by biological treatment of water. If the amount of chloride is beyond the permissible limit then it can corrode by extracting calcium in the form of calcide. Here in the present work the amount of chloride observed is within the permissible limit for Nira river.

Effect of residual H2O2 from advanced oxidation processes on subsequent biological water treatment: A laboratory batch study

H2O2 residuals from advanced oxidation processes (AOPs) may have critical impacts on the microbial ecology and performance of subsequent biological treatment processes, but little is known. The objective of this study was to evaluate how H2O2 residuals influence sand systems with an emphasis on dissolved organic carbon (DOC) removal, microbial activity change and bacterial community evolution. The results from laboratory batch studies showed that 0.25 mg/L H2O2 lowered DOC removal by 10% while higher H2O2 concentrations at 3 and 5 mg/L promoted DOC removal by 8% and 28%. A H2O2 dosage of 0.25 mg/L did not impact microbial activity (as measured by ATP) while high H2O2 dosages, 1, 3 and 5 mg/L, resulted in reduced microbial activity of 23%, 37% and 37% respectively. Therefore, DOC removal was promoted by the increase of H2O2 dosage while microbial activity was reduced. The pyrosequencing results illustrated that bacterial communities were dominated by Proteobacteria. The presence of H2O2 showed clear influence on the diversity and composition of bacterial communities, which became more diverse under 0.25 mg/L H2O2 but conversely less diverse when the dosage increased to 5 mg/L H2O2. Anaerobic bacteria were found to be most sensitive to H2O2 as their growth in batch reactors was limited by both 0.25 and 5 mg/L H2O2 (17–88% reduction). In conclusion, special attention should be given to effects of AOPs residuals on microbial ecology before introducing AOPs as a pre-treatment to biological (sand) processes. Additionally, the guideline on the maximum allowable H2O2 concentration should be properly evaluated.

The problem of dephosphorization using waste recycling.

The article considers optimizing methods for wastewater treatment systems. Nutrients (nitrogen and phosphorus) are discharged from the river basin of the northwest Russia. Disruption of ecological safety and healthy state of water basins takes place when excess amount of nitrogen and phosphorus is discharged from wastewater. This results in eutrophication that is increased growth of seaweeds and, therefore, in ecological system disruption. The cities of the northwest region are short of funds for renovation of water treatment systems. However, the new solution lies in improvement of biological water treatment system by means of chemical injection. The main research task is implementation of methods for enhanced biological phosphorus removal from domestic sewage. The problem of recycling and ecological safety of rivers within the northwest of Russia and the Baltic Sea is not solved completely. That is why for wastewater dephosphorization, the authors suggest using sulfuric acid production waste at chemical plant "Ammophos," Cherepovets (ferrous sulfate FeSO4·7H2O and phosphogypsum СаSO4·Р2О5), as reagents. The advantage of these reagents is their low cost. The authors show the efficiency of the new optimal reagent's combination. Filtering the wastewater through sand filters after secondary settlers increases the total phosphorus removal efficiency up to 90%. The high effect of all types of phosphorus and total nitrogen removal from wastewater can be resulted from the features of micelle creation during coagulation.

Biological Water Treatment Removes Contaminants for Direct Potable Use

Finished Water is a photo feature that profiles working operators and utilities in the news, particularly new and renovated facilities.

From urban municipalities to polar bioremediation: the characterisation and contribution of biogenic minerals for water treatment.

Minerals of biological origin have shown significant potential for the separation of contaminants from water worldwide. This study details the contribution of biologically derived minerals to water treatment operations, with a focus on filtration media from urban municipalities and remote cold regions. The results support biofilm-embedded iron and manganese to be the building blocks of biogenic mineral development on activated carbon and nutrient-amended zeolites. The presence of similar iron and manganese oxidising bacterial species across all filter media supports the analogous morphologies of biogenic minerals between sites and suggests that biological water treatment processes may be feasible across a range of climates. This is the first time the stages of biogenic mineral formation have been aligned with comprehensive imaging of the biofilm community and bacterial identification; especially with respect to cold regions. Where biogenic mineral formation occurs on filter media, the potential exists for enhanced adsorption for a range of organic and inorganic contaminants and improved longevity of filter media beyond the adsorption or exchange capacities of the raw material.

Nanomaterial processing strategies in functional hybrid materials for wastewater treatment using algal biomass

AbstractAlgal cultivation has tremendous potential in wastewater treatment, and its simultaneous biomass production has advantages for the production of value added products such as biodiesel, fertilizers and pharmaceuticals. Some obstacles to obtaining a productive biological water treatment and bioenergy system are the harvesting and processing of biomass. Such issues can be addressed using nano‐bio hybridization approaches by simplifying the microbial harvesting step along with increasing the efficiency of wastewater treatment. This review highlights studies within our research group that are based on the fabrication of functional hybrid materials using algal biomass, including: (i) electrospun nanofibers; (ii) laminar nanomaterials; and (iii) magnetic nanoparticles impregnated in a polymer. All of these techniques have been used for the removal of waste pollutants such as nitrate and phosphate ions. The multidisciplinary techniques have potential to provide effective algal culture systems for industrial applications, while having a significant impact on wastewater treatment. © 2017 Society of Chemical Industry

Biological Treatment of Synthetic Oilfield-Produced Water in Activated Sludge Using a Consortium of Endogenous Bacteria Isolated from A Tropical Area

The aim of this study was to investigate the biological treatment of synthetic oilfield-produced water in activated sludge in an attempt to remove the organic compounds using endogenous bacteria; we also hope to determine the biokinetic coefficients. The activated sludge was operated with various hydraulic retention times (HRT=20 hours, 12 hours, 8 hours), solid retention times (SRT=25 days, 20 days, 15 days, 10 days), and substrate concentrations (500 mg L-1 to 1,100 mg L-1). The endogenous bacterial strains, which were isolated from existing wastewater treatment facilities, were identified as Pseudomonas sp., Enterobacter sp., Bacillus sp1., and Bacillus sp2. It was observed that the highest COD removals were obtained in reactors A (80.7%) and B (82.4%), which had high SRTs (25 days and 20 days) and HRT (20 hours). At shorter SRTs (15 days and 20 days), the concentration of the COD effluent did not comply with the Indonesian regulations for oilfield-produced water quality standards, which means that these SRTs were not recommended as appropriate operational conditions. Furthermore, the results showed that the yield (Y), decay coefficient (kd), maximum specific growth rate (k), and saturation constant (Ks) were 0.533 mg MLVSS mg-1 COD, 0.167 day-1, 0.985 day-1, and 255.46 mg COD L-1, respectively. These biokinetic coefficients (obtained from the Y and Ks values) indicated that although the strains of bacteria can grow well in the reactor, they had low affinities to the substrate, which caused the concentration of the COD effluent to be relatively high.

Passive Biological Treatment of Mine Water to Reduce Conductivity: Potential Designs, Challenges, and Research Needs

The remediation of mine water to preserve receiving water quality has advanced substantially over the past half century, but prospective regulations to limit the conductivity of mining-impacted waters pose a significant new challenge. Conventional approaches to reduce high levels of conductivity in these mine waters are often costly, requiring high levels of maintenance and significant inputs of energy and refined chemicals. In contrast, passive biological treatment (PBT) systems are a relatively low-cost, low-maintenance treatment technology for mine waters that have been used for over three decades. However, their practical ability to reduce conductivity is unclear, given previous research reports focused on the removal of metals, acidity, and solids. A systematic literature review to identify previous reports of PBT systems at the laboratory or field scale that include evaluations of changes in conductivity suggests that decreases in conductivity of 30 to 40% are achievable. Substantial variability in performance is common, however, and conductivity increased markedly in some systems. This variation may be associated with the dissolution of limestone, which is a key treatment material in some systems. Although the development of PBT to serve as pre-, post-, or stand-alone treatment systems targeting conductivity may reduce overall treatment cost in some settings, optimization of these designs requires an increase in the number of published conductivity datasets from similar systems, detailed reports on the key ions contributing to elevated conductivity region to region, and further investigation of the underlying biochemical processes responsible for conductivity reductions.

Photolytic AND Catalytic Destruction of Organic Waste Water Pollutants

The system: water supply source – potable and industrial water – wastewater – sewage treatment – water supply source is necessary for water supply and efficient utilization of water resources. Up-to-date technologies of waste water biological treatment require for special microorganisms, which are technologically complex and expensive but unable to solve all the problems. Application of photolytic and catalytically-oxidizing destruction is quite promising. However, the most reagents are strong oxidizers in catalytic oxidation of organic substances and can initiate toxic substance generation. Methodic and scientific approaches to assess bread making industry influence on the environment have been developed in this paper in order to support forecasting and taking technological decisions concerning reduction of this influence. Destructive methods have been tested: ultra violet irradiation and catalytic oxidation for extraction of organic compounds from waste water by natural reagents.