Biological Treatment Techniques Research Articles

Mathematical Model Development and 3D Printing of Cylindrically Shaped Biofilm Carrier Media from Recycled Plastic Waste for Wastewater Treatment

Wastewater management and purification remain one of the greatest problems of mankind. The biological wastewater treatment technique uses a biofilm media carrier where microorganisms attach themselves to the surface. This biofilter is usually made from virgin plastic pellets and can also be produced from recycled waste plastic and used in wastewater treatment. The need to treat water using low-cost carrier media has led to finding alternative sources of materials for biofilter manufacturing. Therefore, this work is centered on the recycling of waste plastic to make filaments which are then used for 3D printing of a high specific surface area (SSA) less clogging biofilm carrier through the parametric redesign. In the current study, the polypropylene material was recycled to make a 2.85 mm diameter filament compatible with the Ultimaker S3. Moreover, analytical models and governing equations were developed for the design of the K3 Kaldnes and MB3 media. Empirical surface area (SA), specific surface area, and volume of the respective carriers were determined using the model developed. SolidWorks was used to design and evaluate the same parameters which were then compared to model results. The errors in SSA obtained from the model with respect to the SolidWorks results for both the K3 Kaldnes and MB3 media were 0.34% and 0.76% respectively. With these small error margins, the model can serve as a tool and guideline for the designing of cylindrically shaped carriers. By transforming plastics into biofilters, waste plastics are mopped up reducing pollutions. Consequently, the deployment of such biofilters will enhance efficient wastewater treatment for a cleaner environment and the wellbeing of human race.

Characterization and Treatment Technologies Applied for Produced Water in Qatar

Qatar is one of the major natural gas (NG) producing countries, which has the world’s third-largest NG reserves besides the largest supplier of liquefied natural gas (LNG). Since the produced water (PW) generated in the oil and gas industry is considered as the largest waste stream, cost-effective PW management becomes fundamentally essential. The oil/gas industries in Qatar produce large amounts of PW daily, hence the key challenges facing these industries reducing the volume of PW injected in disposal wells by a level of 50% for ensuring the long-term sustainability of the reservoir. Moreover, it is important to study the characteristics of PW to determine the appropriate method to treat it and then use it for various applications such as irrigation, or dispose of it without harming the environment. This review paper targets to highlight the generation of PW in Qatar, as well as discuss the characteristics of chemical, physical, and biological treatment techniques in detail. These processes and methods discussed are not only applied by Qatari companies, but also by other companies associated or in collaboration with those in Qatar. Finally, case studies from different companies in Qatar and the challenges of treating the PW are discussed. From the different studies analyzed, various techniques as well as sequencing of different techniques were noted to be employed for the effective treatment of PW.

Recent developments in physical, biological, chemical, and hybrid treatment techniques for removing emerging contaminants from wastewater

Emerging contaminants (ECs) in wastewater have recently attracted the attention of researchers as they pose significant risks to human health and wildlife. This paper presents the state-of-art technologies used to remove ECs from wastewater through a comprehensive review. It also highlights the challenges faced by existing EC removal technologies in wastewater treatment plants and provides future research directions. Many treatment technologies like biological, chemical, and physical approaches have been advanced for removing various ECs. However, currently, no individual technology can effectively remove ECs, whereas hybrid systems have often been found to be more efficient. A hybrid technique of ozonation accompanied by activated carbon was found significantly effective in removing some ECs, particularly pharmaceuticals and pesticides. Despite the lack of extensive research, nanotechnology may be a promising approach as nanomaterial incorporated technologies have shown potential in removing different contaminants from wastewater. Nevertheless, most existing technologies are highly energy and resource-intensive as well as costly to maintain and operate. Besides, most proposed advanced treatment technologies are yet to be evaluated for large-scale practicality. Complemented with techno-economic feasibility studies of the treatment techniques, comprehensive research and development are therefore necessary to achieve a full and effective removal of ECs by wastewater treatment plants.

Treatment of Natural Fiber for Application in Concrete Pavement

Concrete crack is one of the main problems observed in concrete technology due to drying shrinkage. Incorporating fibers in concrete production is one of the mechanisms implemented to mitigate cracks. Nowadays, investigators concentrate on different techniques to replace human-made fiber with existing natural fibers for fiber-reinforced composite material. Utilization of natural fiber has an initiation for the development of eco-friendly materials by reducing damages caused by human-made materials and saving nonrenewable resources. Natural fibers are readily and abundantly available, sustainable, and biodegradable, with low cost and low density, and have superior specific properties. Nevertheless, there are some limitations of natural fiber compared to human-made fiber. Consequently, significant energy was applied to alter natural fiber’s surface and morphology using physical, chemical, and biological treatment techniques to overcome the limitation. The primary intention of surface treatment is to modify the bond between the fiber surface and the polymer matrix. However, based on this literature review, there were no specific treatment techniques to be followed to select the best one from the others as criteria. It should include all parameters to consider starting from the stage from the cradle to the grave, cost of chemicals, transportation, and labors, including energy consumption and effluent energy. Additionally, their environmental effect also investigated in detail to compare each other.

Chemo-metric engineering designs for deciphering the biodegradation of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are non-polar organic compounds that are omnipresent in the environment and released due to anthropogenic activities through emissions and discharges. PAHs, being xenobiotic and exerts health impacts, thus they attract serious concern by the environmentalists. The stringent regulations and the need of sustainable development urges the hunt for a technically feasible and cost-effective wastewater treatment. Although the conventional physico-chemical treatment are widely preferred, they cause secondary pollution problems and demand subsequent treatment options. This comprehensive review intends to address the (a) different PAHs and their associated toxicity, (b) the remedial strategies, particularly biodegradation. The biological wastewater treatment techniques that involve microbial systems are highly influenced by the different physio-chemical and environmental parameters. Therefore, suitable optimization techniques are prerequisite for effective functioning of the biological treatment that sustains judiciously and interpreted in a lesser time. Here we have aimed to discuss (a) different chemo-metric tools involved in the design of experiments (DoE), (b) design equations and models, (c) tools for evaluating the model’s adequacy and (d) plots for graphically interpreting the chemo-metric designs. However, to best of our knowledge, this is a first review to discuss the PAHs biodegradation that are tailored by chemo-metric designs. The associated challenges, available opportunities and techno-economic aspects of PAHs degradation using chemo-metric engineering designs are explained. Additionally, the review highlights how well these DoE tools can be suited for the sustainable socio-industrial sectors. Concomitantly, the futuristic scope and prospects to undertake new areas of research exploration were emphasized to unravel the least explored chemo-metric designs.

Combined treatment of synthetic textile effluent using mixed azo dye by phyto and phycoremediation

Phytoremediation is one of the biological approaches for remediating textile dyeing effluents. The objective of this study is the use of Pistia stratiotes, an aquatic macrophyte, which was found to degrade the maximum of 83% of mixed azo dye. A phytoreactor was designed and constructed to scale up the process of phytoremediation by P. stratiotes to treat 40 mg/l of synthetic textile effluent. Continuous flow phytoreactor fed with 40 mg/l (cycle 1) which showed maximum decolorization of 84%, COD removal was about 61%, BOD which was reduced up to 71.9%, and TDS removal was about 72% respectively. Further to remove the residual color and toxic effects of the dyes, Phycoremediation was followed for the mixed azo dyes using the microalgae Chlorella vulgaris which showed a maximum decolorization of 99% in the batch study and 74% in the scale-up study where the treated effluent was at the most minimal discharge. Phytotoxicity tests showed 80% of germination in treated effluent, and the plants in untreated wastewater had inhibited growth that indicates only 30% of germination. Such combined biological treatment techniques were put forward to be the most eco-friendly technology, which is cost-effective and attain zero discharge of the textile effluent.

Karakteristike otpadnih voda iz rafinerija, tehnike prečišćavanja i njihova ograničenja - pregled

Large quantities of wastewater generate from refineries in the process of crude oil usage, distillation, and cooling systems. The wastewater samples need to be treated before disposing into the environment. Disposal of the untreated refinery wastewater causes problems for the water sources and environment. The aim of this work was to study the characteristics, treatment techniques, and limitations of refinery wastewater treatment. A number of tables were prepared to summarize and review wastewater characteristics, treatment process, and the operational limitations. Results revealed that values of some parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), phenols, oil and grease, and total suspended solids (TSS) were 40.25 mg/L to 8,000 mg/L, 80 mg/L to 21,000 mg/L, 3.5 mg/L to 128 mg/L, 12.7 mg/L to 50,000 mg/L, and 22.8 to 2,580 mg/L, respectively. Numerous treatment technologies were used for the treatment of refinery wastewater. Treatment techniques have benefits, weaknesses, and operational limitations. Most amount of the TSS, oil and grease, organic materials are eliminated in the primary and secondary treatment units. Tertiary/Advanced treatment units are necessary for removal of the remaining portions of the contaminants, heavy metals, nitrogen compounds, and phosphorus. Combination of physical, chemical and biological treatment techniques increase removal efficiency of the contaminants.

Integration of submerged microfiltration and cold plasma for high-strength livestock excreta

Numerous biological treatment techniques have been studied for better management of high-strength livestock urine and manure (LUM) but it is still challenging. To gain an advanced option for LUM management, this study proposes a physicochemical process combining microfiltration (MF) and cold plasma (CP). Experimental design applying single CP, single MF, and the integrated system coupling CP and MF (CP + MF) evaluates the performances of the configurations while reducing hydraulic retention time (HRT) from 3 d to 1 d. Results demonstrate that the CP + MF can maximize the removal efficiencies of total nitrogen (72.4 %), total phosphorus (57.8 %), NH4-N (73.3 %), turbidity (99.1 %), dissolved organic carbon (71.3 %), suspended solids (98.7 %) at HRT 3 d. It was verified that CP, even at the lowest HRT (1 d), significantly reduces membrane resistance (0.4 × 1014 m−1) compared to the control (1.5 × 1014 m−1) which leads to lower transmembrane pressure (TMP, 45.6 kPa) and inclined flux (4.4 L/m2/h) than those of the control (45.6 kPa TMP and 2.2 L/m2/h). These results contribute to the advanced treatment of LUM with a cost-effective and environmentally friendly strategy via technical convergence.

Applicability and new trends of different electrode materials and its combinations in electro coagulation process: A brief review

Differenttechnologiessuchasphysical,chemical,biological,advancedoxidationsand electro-chemical methods areinvolvedinthetreatmentofindustrialeffluent. The widely followed biological treatment techniques are required more time, wide operational space and are not effective for wastewater contains heavy metal and hazardous elements. The advanced oxidation process needs tremendous operational cost and is usually procure high immaculate water. The chemical coagulation process is time delaying and brings about a huge volume of sludge. In the electrostatic coagulation process, the electrode plates are dissolved in the wastewater by a direct current source of metal electrodes immersed in the effluent. Electrocoagulation (EC) has a newly followed method used for treating industrial effluent due to its adaptability and cost-effective eco-friendly method. EC has been used for treating a wide range of industrial effluent. These metal ions combine with hydroxide ions to form metal hydroxide which acts as the coagulant for the destabilization of suspended as well as dissolved pollutants in the industrial wastewater. Therefore, the intention of this review paper is the possibility of EC for the treatment of industrial effluents as well as energy consumption in the EC.

Environmental performance of building integrated grey water reuse systems based on Life-Cycle Assessment: A systematic and bibliographic analysis

The increasing demand for fresh water has been a global concern for decades. Desalination and water transportation systems consume an ample amount of energy, which also adds to the environmental pollution. This has led to a constant look-out for more viable options to conserve freshwater resources without compromising the environmental quality. The building sectors are remarkably the largest consumers of fresh water in the world; thus, the reclamation and reuse of greywater for non-potable purposes helps to reduce a significant amount of water consumed within a building. This study critically reviews the environmental performance of building-integrated greywater treatment systems compared to the conventional treatment systems deployed. Life-Cycle Assessment (LCA) is the method used to identify the environmental impacts associated with both the systems during their entire life span. The greywater treatment techniques and the guidelines for its reuse are also investigated. The bibliographic analysis was systematic, and the resources for this study were chosen after three stages of quality assessment. The study found physical and biological treatment techniques to be beneficial as they produce excellent quality of treated greywater for reuse. The environmental assessment by various studies prefers the reuse of greywater over its disposal. Guidelines for the reuse of treated greywater have recently been proposed by various countries and building rating systems. This study aims to address the policymakers, governmental and environmental organizations, mainly situated in the water-stressed areas such as the Middle East and North Africa (MENA) region, to raise awareness and initiate greywater reuse techniques within residential and commercial building sectors.

Proportional studies of liquefied samples- Sewage, Hygienic and treated sewage water – case study of Gwagwalada, Abuja.

This study is on comparative study of three liquefied (sewage, hygienic and treated sewage water) Gwagwalada, Abuja, Nigeria. Actuated sludge system was utilized as an example of the biological treatment technique, whereas wastewater from the estate septic cistern, actuated sludge treatment plant treated water from the ejection was acquired and physicochemical features of the mixing liquefied samples was carried out in the laboratory so as to ascertain the amount of Ammonia (NH3), calcium oxygen demand (COD), Sulphate (SO4), Biological Oxygen demand (BOD), Chlorine (Cl), Total dissolved solid (TDS), temperature(T°C), Salinity and PH of the sewage, hygienic and the treated sewage water. Domestic wastewater treatment plant of five hundred cubic meters per day per capacity (500m3/day/cap) has efficient treatment proficiency and every parameter treated is within FME standard. This study will display the significance, viability of recovery and reprocess of organic waste in region with no comprehensive application besides, decreasing environmental impact, reused sewage effluent for drinking, cooking and agricultural purposes.

Impacts of environmental factors on AHL-producing and AHL-quenching activities of aerobic granules

Aerobic granule is widely recognized as a promising biological wastewater treatment technique. Acyl-homoserine lactone (AHL)-mediated quorum sensing and quenching are reported to be involved in the formation of aerobic granules. However, little is known about how environmental factors affect the AHL-producing and AHL-quenching communities and their activities in aerobic granules. Therefore, in this work, the bacterial community of aerobic granules was explored and the impacts of substrate, electron acceptor, sludge concentration, pH, and temperature on the AHL-related communities and activities of aerobic granules were examined. These factors were found to affect the AHL-related activities, and thereby change the AHL level. The AHL-producing activities were observed to be more sensitive to the variation of these factors than the AHL-quenching activities. These findings help to establish the links between environmental factors and AHL-related activities and thus provide useful guides for the operation of aerobic granule systems.

The landfill biocell as an ecofilter for recycling of bio-energy and nutrients from residual wastes

Anaerobic fermentation in landfill reactorcells is a biological waste treatment technique where both energy and nutrients can be recovered. The landfill reactorcell ("biocell") serves as an ecological filter, where energy is extracted as biogas while nutrients are recovered through the leachates and can be used as fertilizer in e.g. energy forests, and thus brought back to an ecological cycling. At the same time anaerobic conditions result in an effective immobilization of heavy metals and other pollutants e.g. as insoluble metal sulphides, which are immobilized in the fermentation rest. The long-lived fraction, remaining after the fermentation process has declined, containing a high content of lignin, serves as a water-holding matrix, which helps to enforce a sustainable high moisture level, and thus sustainable anaerobic conditions with heavy metals retained on a longterm bases. Also non-degradable products, like plastics, help to shield off oxygen and maintain reliable anaerobic conditions. Landfilling of organic matter is a measure to counteract the increasing concentrations of CO2 in the atmosphere, resulting from different human activities. Landfilling at anaerobic conditions means that a small fraction of the organic matter is long-term accumulated in the landfill. Accordingly landfills have similar carbon accumulating effects as natural peatlands and lake or sea sediments. With low investment costs it is possible to convert traditional landfills to well controlled biological treatment facilities. Thus the technique can be performed both in large and small scale, avoiding energy demanding road transportation.

Molecular detection and genotypic characterization of enteric adenoviruses in a hospital wastewater.

Hospital wastewater (HWW) represents a major source of the diffusion of many antibiotics and some toxic pathogenic microorganisms in the aquatic environment. Sanitation services play a critical role in controlling transmission of numerous waterborne pathogens, especially enteric human adenoviruses (HAdVs) that can cause acute gastroenteritis. This study intended to evaluate the human adenoviruses (HAdVs) detection rates, to determine the genotype of these viruses and to assess the efficiency of HAdVs removal in hospital pilot wastewater treatment plant (PWWTP) in Tunis City, Tunisia. Therefore, hospital wastewater samples (n= 102) were collected during the study year from the two biological wastewater treatment techniques: natural oxidizing ponds and the rotating biological disks or biodisks. Nested polymerase chain reaction (Nested PCR) was used to evaluate the HAdVs detection rates. The genotype of HAdVs positive samples was achieved by the sequencing of the PCR products. HAdVs were detected in 64% (65/102) of positive wastewater samples. A substantial increase in the frequencies of HAdVs was observed at the exit of the two wastewater treatment techniques studied. The typing of HAdVs species F showed the occurrence of only HAdVs type 41. This data acquired for the first time in Tunisia showed high persistence and survival of HAdVs in the two biological wastewater treatment techniques experienced, and mainly highlighted the poor virological quality of the treated wastewater intended for recycling, agriculture reuse, and discharges into the natural receiving environments. Consequently, tertiary wastewater treatment appeared necessary in this case to decrease the load of enteric viruses flowing in the water environment.

The Detoxification of Heavy Metals in the Phosphate Tailing-contaminated Soil through Sequential Microbial Pretreatment and Electrokinetic Remediation

ABSTRACTIn this paper, the heavy metals (HMs) in the phosphate tailing-contaminated soil were detoxified using the microbial pretreatment in combination with electrokinetic remediation (EKR).. This study provides compelling evidence that the sequential usage of the bioleaching and electrokinetics is superior to the individual method for the detoxification of Pb, Cu, Zn, Cd, and As from the contaminated soil. In the sequential system, the detoxification efficiency of Zn was the highest and that of As was the lowest. Except the element As, the detoxification efficiencies of HMs in the sequential system were generally higher than that using the single biological treatment and EKR technique. Bioleaching, generation of the passivation, and migration direction of the ions are concluded as the factors attributable to the final results; and, the initial increase in the inoculation doping of Thiobacillus ferrooxidans considered has no obvious impact on improving the final detoxification efficiency rates.

Application ro techniques with "open channel" membranes to treat wastewater for recycling and reuse: modern methods of environmental protection and water resources management

The solution to contemporary ecological problems such as wastewater reuse requires rational water resources management, and in turn, rational water resources management requires the development of new, more efficient techniques. The modern concept of rational water resources management requires the development of new efficient techniques that provide wastewater treatment and reuse. For many local industries, the problem of wastewater treatment and discharge into surface reservoirs can’t be solved through the use of conventional biological treatment techniques. Current discharge standards require very strict removal of a number of impurities such as ammonia, nitrates, phosphate, etc. To reach this level of removal, expensive reagents and sorbents are used. As RO membranes simultaneously reject all dissolved impurities such as BOD, TDS, ammonia, phosphates etc., they become very attractive for the direct treatment of wastewater without biological stage. To treat wastewater, specially designed membrane "open channel" modules are used that do not possess "dead areas" that cause fouling or require pretreatment. A solution to the concentrate disposal problem is presented that consists of reducing of initial wastewater volume by 100 times. Concentrate is withdrawn from membrane unit as sludge humidity. Local utilities and privately-held industrial sites are encouraged to reuse wastewater and reduce freshwater intake, thereby prompting rational water management and reducing environmental pollution.

Evaluation of Wastewater Treatment Plants in El-Gharbia Governorate, Egypt

The present study has been undertaken to evaluate performance efficiency of wastewater treatment plants in El-Gharbia governorate in Egypt. The wastewater treatment plants using different biological treatment techniques (conventional activated sludge, oxidation ditch, extended aeration, rotating biological contactors and aerated lagoons processes). Wastewater samples were collected from both influent and effluent of each plant and the wastewater quality were determined at central laboratory of Garbyia Water Co. The performance of each plant was estimated based on the treated wastewater quality data. Correlations between influent and effluent TSS, COD and BOD5 were developed. Kotour WWTP operates with the oxidation ditch technology exhibits the highest performance efficiency, while Tanta WWTP operates with conventional activated sludge technology exhibits the lowest one. The results show that, all collected samples from Tanta, and El Mehala El Kobra WWTPs were exceeding the Egyptian Permissible limits (COD: 80 mg/l) while the samples collected from Mehalet Marhom, Mehalet Menof, Kotour, El Santa, Shernak and Zefta were complying the Egyptian regulations.

Emission factor for atmospheric ammonia from a typical municipal wastewater treatment plant in South China

Atmospheric ammonia (NH3), a common alkaline gas found in air, plays a significant role in atmospheric chemistry, such as in the formation of secondary particles. However, large uncertainties remain in the estimation of ammonia emissions from nonagricultural sources, such as wastewater treatment plants (WWTPs). In this study, the ammonia emission factors from a large WWTP utilizing three typical biological treatment techniques to process wastewater in South China were calculated using the US EPA's WATER9 model with three years of raw sewage measurements and information about the facility. The individual emission factors calculated were 0.15 ± 0.03, 0.24 ± 0.05, 0.29 ± 0.06, and 0.25 ± 0.05 g NH3 m−3 sewage for the adsorption-biodegradation activated sludge treatment process, the UNITANK process (an upgrade of the sequencing batch reactor activated sludge treatment process), and two slightly different anaerobic-anoxic-oxic treatment processes, respectively. The overall emission factor of the WWTP was 0.24 ± 0.06 g NH3m−3 sewage. The pH of the wastewater influent is likely an important factor affecting ammonia emissions, because higher emission factors existed at higher pH values. Based on the ammonia emission factor generated in this study, sewage treatment accounted for approximately 4% of the ammonia emissions for the urban area of South China's Pearl River Delta (PRD) in 2006, which is much less than the value of 34% estimated in previous studies. To reduce the large uncertainty in the estimation of ammonia emissions in China, more field measurements are required.

Impact of Biological Treatment Techniques on Perfluoroalkyl Acids Emissions in Municipal Sewage

To study the impact of biological treatment techniques on perfluoroalkyl acids (PFAAs) emissions in municipal sewage, high-performance liquid chromatography-tandem mass spectrometry was combined with WAX extraction enrichment to analyze the content and distribution of 14 PFAAs in the influent and effluent of 10 municipal sewage treatment plants that adopted 3 biological treatment techniques including sequencing batch reactor (SBR), oxidation ditch, and A/O-involved processes in Shenzhen, China. The mass flow of PFAAs under different biological treatment techniques was also compared. Results showed that average ΣPFAAs of the ten sewage treatment plants decreased from 32 to 26 ng/L after treatment, showing no significant difference, but average daily ΣPFAAs mass flow significantly decreased from 8.1 to 6.1 g/day (p < 0.05). Through treatment, short-chain PFAAs and perfluoroalkyl carboxylic acids (PFCAs) with removal rates of 43 and 29 % decreased significantly (p < 0.01), but long-chain PFAAs and perfluorosulfonates (PFSAs) with removal rates of −0.68 % and −21 % did not. The plants using SBR had an average ΣPFAAs removal rate of 35 %, comparable to those using A/O-involved processes (27 %). However, the plants using oxidation ditch technique had an average long-chain PFAAs removal rate of −51 %, making their average ΣPFAAs removal rates reaching −25 %, significantly lower than the other two techniques (p < 0.05).

Enhanced dephenolization using sequential biological and photocatalytic treatment

Novel eco-preserving system was developed by combining biological and photocatalytic treatment techniques for synergistic removal of phenol from aqueous media. Penicillium chrysogenum a filamentous fungus was able to remove 77.3 % out of 125 mg/l phenol within 168 h. On the other hand, ZnO nanoparticles that were developed within low density polyethylene(LDPE)-g-(styrene(Sty)-co-acrylic acid(AAc)) sheets, prepared by γ-radiation induced graft copolymerization, were able to remove 77.6 % out of 125 mg/l phenol within 24 h. Combining both techniques via the employment of the developed LDPE-g-(Sty-co-AAc)/ZnO nanocomposite for 6 h prior to 18 h of biological treatment resulted in the removal of 89.5 % out of 125 mg/l phenol. The degradation products were assayed using fourier transform infrared spectroscopy (FT-IR), while enzyme assay was performed to propose a pathway for degradation. A phytotoxicity test showed that the synergistic degradation products were less toxic than phenol. Moreover, LPDE-g-(Sty-co-AAc)/ZnO nanocomposite sheets were used three times with the same efficiency. The aforementioned results recommend biological/photocatalytic combined treatment technique as a promising eco-preserving system that reduce the potential toxicity of the treated waste water that offer a bonus of practicality and cost-effectiveness.