Development Of Wastewater Treatment Research Articles

Tailoring electrospun nanocomposite fibers of polylactic acid for seamless methylene blue dye adsorption applications.

The introduction of biopolymers, which are sustainable and green materials, desegregated nature's water purification proficiency with science and technology, opens a new sustainable methodology in water reclamation. In order to introduce an efficacious adsorbent system for MB dye-toxic pollutant, adsorption, providing robust mechanical properties and facile processability, a facile system was introduced via electrospinning utilizing polylactic acid (PLA) and Ti3C2Tx, viz., PMX. The addition of 3 wt.% Ti3C2Tx led to a 3-fold substantial augmentation in the uptake capacity of the membrane from 197.28 to 307 mg/g when the adsorbate concentration was 100 ppm. The adsorption followed a PSO behavior, proposing that the rate-limiting stage is chemisorption and data best fitted to Freundlich isotherm, indicating heterogeneous adsorption sites and multi-layer adsorption. Further, biodegradability was studied by simulating natural environmental conditions where the nanofibers exhibited 42-64% degradation after 270 days. Based on the result with PLA, it is anticipated that the prepared fibrous system will introduce a new perspective as a potential candidate for MB removal from wastewater, opening new directions toward the research and development in wastewater treatment with electrospun biopolymer fibers using waste PLA.

Degradation of different wastewater by a biological sponge iron system: microbial growth and influencing factors.

The bio-ZVI process has undergone widespread development in wastewater treatment in recent years. However, there has been limited examination of the growth and degradation characteristics of functional microorganisms within the system. In the present research, strains were isolated and identified from the bio-ZVI system constructed by sponge iron (encoded as SFe-M). The consistency of operating conditions in treating different wastewater was explored. Three SFe-acclimated microorganisms exhibiting characteristics of degrading organic pollutants and participating in the nitrogen removal process were isolated. The adaptation time of these microorganisms prolonged as the substrate toxicity increased, while the pollutant degradation was related to their metabolic rate in the logarithmic phase. All these functional bacteria exhibited the ability to treat wastewater in a wide pH range (5-8). However, the improper temperature (such as 10 °C and 40 °C) significantly inhibited their growth, and the optimal working temperature was identified as 30 °C. The iron dosage had a significant impact on these function bacteria, ranging from 1 g L-1 to 150 g L-1. It was inferred that the SFe-acclimated microorganisms are capable of resisting the poison of excessive iron, that is, they all have strong adaptability. The results provide compelling evidence for further understanding of the degradation mechanism involved in the bio-ZVI process.

Quantifying future sanitation scenarios and progress towards SDG targets in the shared socioeconomic pathways

Two main targets of SDG 6 (Sustainable Development Goal), clean water and sanitation, are SDG 6.2, to achieve universal and equitable access to improved sanitation and to phase out unimproved sanitation (include pit latrines without a slab or platform, hanging latrines, bucket latrines and open defecation) and SDG 6.3, to halve the proportion of untreated wastewater by 2030. We compiled a global sanitation database for 200 countries. Starting from recent trends, we constructed a wide spectrum of contrasting future scenarios, i.e. the five Shared Socio-economic Pathways (SSP1-5) whereby the SSP2 scenario is ‘middle of the road’ scenario. The sanitation scenarios differ due to contrasting pathways for population growth and urbanization, economic growth and the SSP narratives.Our results indicate that it will be difficult to achieve the SDG 6 target. Target 6.2 on improved sanitation is expected to be achieved between 2070 and 2090 in SSP1, SSP2 and SSP5, while the target will not be achieved by 2100 in SSP3 and SSP4. Unimproved sanitation is projected to be phased out by 2070 in SSP1 and SSP5, or beyond 2100 in SSP3 and SSP4. The percentage of households with sewerage connection will be between 51% in SSP3 and 75% in SSP5 in 2050, and respectively 60% and 95% in 2100.Target SDG 6.3 on improving wastewater treatment will be reached by 2030 only in SSP1, followed by SSP2 and SSP5 between 2040 and 2050, while in SSP3 and SSP4 this target is not reached by 2100. The developments in wastewater treatment, expressed as percentage nutrient removal, showed an increase from 14% in 2015 to 45% in 2050 and 80% in 2100 in SSP1. But in SSP3, the global percentage is expected to have hardly changed by 2050 and have declined to 12% by 2100 due to the population growth in Sub-Saharan Africa.There is a major contrast between countries and regions. In the period between 2000 and 2015, although globally the percentage of people with unimproved sanitation declined, in 7% of the 200 countries the number of people with unimproved sanitation increased. Also, wastewater treatment globally improved, but in 16 countries it deteriorated. This inequality is particularly important in SSP3 and SSP4 where the lack of improved sanitation will continue till 2100.

Adsorption of malachite green dye over synthesized calcium silicate nanopowders from waste materials

The synthesis of calcium silicate (CS) nanopowders from marble sawing dust and silica fume using microwave irradiation (MWI)-assisted route has been studied. Coalesced tiny cubes and rods with flower-like shapes in the range of ∼ 150 nm in size with a surface area of 18.357 m2g−1 have been obtained as observed from FE-SEM images and detected by BET measurements, respectively. According to the Langmuir isotherms, increasing the temperature from 30 to 45 °C increases the maximum monolayer adsorption capacity, qmax, from 13.44 to 59.95 mg/g. The kinetic studies indicated that the adsorption kinetics of malachite green dye (MG) over calcium silicate nanopowders followed the pseudo-first-order with a high correlation coefficient (R2) of 0.7901. The experimental results also showed that the MG dye adsorption fitted better with the Freundlich model with a high correlation coefficient (R2 = 0.9474) which suggested the multilayer physisorption process. The calculated thermodynamics parameters (ΔG° = 0.019 to − 2.898 kJ mol−1, ΔS° = 109.83 J mol−1 and ΔH = 32.79 kJ mol−1) declared the adsorption feasibility, with degrees of randomness. In our study, adsorption measurements, schemes, and mechanism have been discussed to shed light on the advances in this field. The MWI route using waste raw materials will significantly lower overhead costs of adsorbent synthesis and will allow development in wastewater treatment.

Enhanced Simultaneous Nitrogen and Phosphorus Removal Performance of the AGS-SBR Reactor Based on the Effects of the C/N Ratio and Microbial Community Change

In recent years, the development of AGS technology will likely lead to a new direction in wastewater treatment development in the future. Traditional sewage treatment technology has been unable to meet the increasingly strict quality standards of wastewater treatment and limited land requirements. AGS technology may be a new method to replace traditional sewage treatment technology. However, the stable operation of AGS technology is a major obstacle to the popularization and development of this technology. The C/N ratio is an important parameter affecting the stability and simultaneous nitrogen and phosphorus removal of AGS technology. In order to enhance the nitrogen and phosphorus removal capacity of a low-load aerobic granular sludge SBR (AGS-SBR) system, changes in the morphology, EPS, and simultaneous removal of organic matter, nitrogen, and phosphorus in the AGS system were studied by regulating different C/N ratios (20, 15, 10, 5). The changes in the microbial community in the system were deeply analyzed by high-throughput sequencing technology. The results showed that different C/N ratios have a significant effect on the nitrogen removal rate of AGS but have little effect on the removal rate of organic matter and phosphorus. When the C/N ratio was reduced to 10, it was conducive to the stability of the low-load AGS-SBR system. An effective C/N ratio promoted the secretion of EPS by microorganisms, and the increase in the PN value contributed to the stability of the granular sludge, which became smooth and compact. The main functional genus in the system were norank_f__Saprospiraceae, Tetrasphaera, Ellin6067, and Pseudomonas. In addition, the simultaneous nitrogen removal performance of the system was significantly improved.

Microbial fuel cells for waste nutrients minimization: Recent process technologies and inputs of electrochemical active microbial system

Still, in the current period, non-renewable energy sources have contributed to fulfill the current energy requirement and it causes the deficit of available stocks with emission of pollutant byproducts components. In recent years, efforts were made to harness the sustainable/ renewable fuels from renewable sources/ waste, complex organic matters including biomass at global level. Researchers have put attention on harnessing energy from wastewater and MFCs systems. This MFC approach utilizes the wastewater as feed/ carbon sources to generate bioenergy such as bio- hydrogen and electricity in a sustainable and efficient way via completing the wastewater treatment. This approach consists of anode and cathode electrodes with proton exchange membrane (PEM). Microbial fuel cells are utilized with other effective approaches (anaerobic digestion/ fermentation, local demand-based-MFC approach) that are applied to utilize biowastes for microbial cell growth and electron emission. This review discusses the recent and technologically advanced approach such as microbial fuel cells (MFCs). MFCs can apply to fulfill the increasing trends of global energy demand, found with more utilization in home appliances in urban areas, industrial tasks and transportation sectors. Last few decades, there have been recent modifications in MFCs configurations and design that have improved performance of MFCs. Recent design and configuration of MFCs have shown the removal of maximum chemical oxygen demand (up to 94–97%) with generation maximum current output (up to 5.23 mA) from wastewater. This review presents a comprehensive collection of recent information about technologies and design of MFCs with implementation of microbial electrogene with development of wastewater treatment having sustainable fuel/ energy generation at an effective level.

Using life cycle assessment at an early stage of design and development of zero discharge brine treatment and recovery

It is critical that the development of new technologies to solve environmental problems do not shift the burdens (impacts) to other mediums. Therefore, to ensure the optimum environmental design of water treatment and recovery systems, it is pertinent to apply life cycle assessment (LCA) at an early stage of development. Using LCA at an early developmental stage is known as prospective LCA and is particularly challenging due to the low data availability or quality. The aim of this study is to highlight the opportunities and challenges of using prospective LCA in the development of water treatment and recovery technologies. To do this we utilise two case studies from the EU Zero Brine project and apply LCA at two developmental stages. The treatment systems are specifically tailored for each case to treat the individual brine compositions and selectively recover its constituents. The first stage LCAs are based on laboratory experiments and engineering-based calculations, whilst the second stage assessments use improved input data from pilot plants and simulation. The paper compares the analyses of both stages, identifies key differences and discusses these disparities. In addition, it provides insights on the challenges of applying LCA for the design and development of wastewater treatment and recovery systems.

Wastewater treatment and reuse situations and influential factors in major Asian countries

As Asia is the most populous continent in the world, the contradiction between water supply and demand is increasing. Wastewater treatment and reclaimed water use are important means to solve the contradiction between supply and demand and realize the sustainability of the water management system. Based on the data collected from 48 typical countries and regions in Asia, this study evaluates the possible influential factors on wastewater treatment and reclaimed water use such as Gross Domestic Product (GDP) level, water resource availability, water withdrawn and water stress. It is identified that per capita GDP and water stress are important factors affecting wastewater treatment and reclaimed water use. Although reclaimed water use in most Asian countries is still at the early stage, the development of wastewater treatment is conducive to the development of reclaimed water. The results of this study are believed to be useful in improving water management and sustainability levels in Asian countries.

Drivers of contaminant levels in surface water of China during 2000–2030: Relative importance for illustrative home and personal care product chemicals

Water pollution are among the most critical problems in China and emerging contaminants in surface water have attracted rising attentions in recent years. There is great interest in China's future environmental quality as the national government has committed to a major action plan to improve surface water quality. This study presents methodologies to rank the importance of socioeconomic and environmental drivers to the chemical concentration in surface water during 2000–2030. A case study is conducted on triclosan, a home and personal care product (HPCP) ingredient. Different economic and discharge flow scenarios are considered. Urbanization and wastewater treatment connection rates in rural and urban areas are collected or projected for 2000–2030 for counties across China. The estimated usage increases from ca. 86 to 340 t. However, emissions decreases from 76 to 52 t during 2000–2030 under a modelled Organisation for Economic Co-operation (OECD) economic scenario because of the urbanization, migration and development of wastewater treatment plants/facilities (WWTPs). The estimated national median concentration of triclosan ranges 1.5–8.2 ng/L during 2000–2030 for different scenarios. It peaks in 2009 under the OECD and three of the Intergovernmental Panel on Climate Change (IPCC), A2, B1 and B2 economic scenarios, but in 2025 under A1 economic scenario. Population distribution and surface water discharge flow rates are ranked as the top two drivers to triclosan levels in surface water over the 30 years. The development of urban WWTPs was the most important driver during 2000–2010 and the development of rural works is projected to be the most important in 2011–2030. Projections suggest discharges of ingredients in HPCPs - controlled by economic growth - should be balanced by the major expenditure programme on wastewater treatment in China.

Efficiency estimation of cation-exchange recovery of heavy metals from solutions containing their mixtures

The object of research is the washing waste water of galvanic plants containing heavy metal cations. The most common reagent methods for purification of galvanic drains do not provide the required degree of water purification, are accompanied by the loss of valuable components and the formation of significant amounts of toxic sludge. Ion exchange is promising in development of wastewater treatment of galvanic productions. One of the most important problems of ion-exchange technology is the processes of regeneration of ion exchangers, and, in particular, the recycling of spent regeneration solutions. The most promising in the recovery of regeneration solutions is the electrochemical method. However, electroextraction of zinc and nickel is practically impossible from acidic solutions without separation of the electrode space by the membrane. In addition, effluents from the galvanic industry contain mixtures of heavy metal ions. This complicates the process of wastewater treatment and the return of valuable components to production. In the course of the study, a strongly acidic cation exchanger KU-2-8 in the Na + -form is used to study the processes of combined sorption of heavy metal ions. Regeneration of the cation exchanger is carried out with solutions of sulfuric and hydrochloric acids. Electroextraction of zinc and nickel from acid regeneration solutions is carried out in a two-cell electrolyzer with an anion-exchange membrane MA 41. The obtained results indicate that under conditions of the concentration of heavy metals on cation exchanger KU-2-8, efficient separation can’t be achieved. It is established that ions of heavy metals are sorbed individually and in mixtures with other ions of heavy metals are effectively desorbed by solutions of sulfuric and hydrochloric acids. The use of a two-cell electrolyzer, in contrast to carrying out electrolysis processes without separation of the electrode space, almost completely eliminates zinc and nickel ions from acidic regenerative rods. And to obtain a solution of sulfuric acid in the anode chamber at a concentration of 239–651 meq/dm 3 .

Fabrication of superhydrophobic Pt3Fe/Fe surface for its application

Well-defined Pt3Fe/Fe superhydrophobic materials on iron sheet with special properties, such as corrosion resistance, superhydrophobicity and superoleophilicity, was fabricated. The fabrication process involved etching in hydrochloric acid aqueous solution and simple replacement deposition process without using any seed and organic solvent, and then annealing. The electrochemical measurements show that the resultant surface in 3.5% sodium chloride solution displays good corrosion resistance. Also, it is proved that the obtained surface has better mechanical abrasion resistance via scratch test. The superoleophilicity and low water adhesion force of the obtained surface endow it high oil/water separation capacity. The as-prepared nanocomposites display enhanced catalytic activity and kinetics toward degradation of methyl orange. In particular, it possesses the most efficient degradation capacity (95%) towards methyl orange at a high concentration (17.5mg/L) in 80min. The improved stability and excellent catalytic activity of the Pt3Fe/Fe nanocomposites promise new opportunities for the development of waste water treatment.

Development of waste water Treatment Using Solar Energy

Development of waste water Treatment Using Solar Energy

Regulation and reality: some reflections on 50 years of international experience in water and wastewater

Over 50 years of experience in the water sector is presented through the lens of a practitioner who has worked in over 30 countries mainly on wastewater but also on utility management, privatization and institutional development. This article tracks important developments in wastewater treatment leading to reuse but, more importantly, describes experiences where effective regulation and reality have parted company.

The Latest Applications of Chitin and Chitosan in Wastewater Treatment

Chitosan has multiple applications due to its advantages including availability, biocompatibility and biodegradability in food, agriculture, material science and so on. In recent years, chitosan was frequently chosen as absorbent of wastewater and reached a satisfactory effect. It should be noted that it is one of most important links in the environment enhancement chains using chitosan as absorbent of heavy metal in wastewater treatment. Chitosan-molecularly imprinted polymers with favorable absorption ability can meanwhile absorb many heavy metal including Cu2+, Hg+, Mn2+ion, etc. The aim of this paper is to review their latest development in wastewater treatment for providing helpful guidances for researcher in this field.

Linking sanitation and wastewater treatment: from evaluation on the basis of effluent pollutant concentrations to evaluation on the basis of pollutant removal efficiencies

The evaluation of centralised wastewater treatment plants (WWTPs) in planning and management is sometimes based solely on effluent pollutant concentrations or pollutant loads. For sanitation purposes, the effluent pollutant concentrations/loads of WWTPs are important; of course, but from the point of view of wastewater treatment, the pollutant removal performance should also be evaluated. Focussing on low- and middle-income countries, especially those in tropical regions, published kinetics studies on biological WWTPs (such as oxidation ditches and aerated lagoons) are summarised in this paper. In most studies, effluent pollutant concentrations/loads are described as first-order linear functions of influent pollutant concentrations/loads. Therefore, pollutant removal efficiencies can be expressed as first-order linear functions of the reciprocal of influent pollutant concentrations/loads with negative coefficients. This implies that pollutant removal efficiencies increase with influent pollutant concentration/load increases. Based on pollutant removal efficiency functions, biological or ecological WWTPs when operating with small influent pollutant concentrations/loads should change their management to increase influent pollutant concentrations/loads in order to increase pollutant removal efficiencies. It may, however, be possible for technological development in wastewater treatment to overcome this problem.

Using a GIS transfer model to evaluate pollutant loads in the Lake Kinneret watershed, Israel

Lake Kinneret (Sea of Galilee) is the only large surface water body in Israel, encompassing an area of 167 km2 and supplying some 30% of the country's fresh water. Pollution from anthropogenic sources and water abstraction for domestic and agricultural uses has long been threatening the water quality of the lake. Point-source pollution in the watershed has decreased drastically with the development of wastewater treatment. However, diffuse pollution from agricultural activities is still an unresolved issue. In this paper we present an application of AVGWLF (a GIS-based watershed load model) to the Lake Kinneret watershed. The model allows one to simulate daily stream flows and monthly sediment, nitrogen, and phosphorus loads discharged to the lake from the surrounding watershed. Results from simulations yield a satisfactory correspondence between simulated and measured daily water volume. Partition by source of total phosphorus delivered to the lake in the period of 2000-04 confirms the reduction in point source nutrient contribution due to improvement of wastewater treatment facilities in the area. Future management should focus on reduction of nutrients originating from septic systems (point sources) and pasture and cropland areas (diffuse sources). Results from simulations will enable watershed managers to prioritize effective management alternatives for protecting the water quality in the lake.

A tanks-in-series bioreactor to simulate macromolecule-laden wastewater pretreatment under sewer conditions by Aspergillus niger

Sewers are typically a means of transporting wastewater to a treatment facility, with little biotransformation of the soluble polymeric organic matter by suspended biomass. In the interest of providing an effective pretreatment of wastewater in a sewer network, it is necessary to design an accurate tool simulating sewer conditions and introduce an appropriate biomass for macromolecular pollutant degradation. Such a model reactor was built using a tanks-in-series design and the degradation of a polysaccharide (starch) by Aspergillus niger MUCL 28817 was studied. Starch degradation and the accumulation of intermediates (hydrolysis fragments) in the individual reactors were quantified under transient conditions, at a mean hydraulic residence time of 17 h. Starch was degraded by 90% in this reactor system and an accumulation of oligosaccharides with molecular weight lower than 1000 Da was observed. These results may be helpful in the development of wastewater treatment in sewers and in the alleviation of the burden on undersized wastewater treatment systems.

Development of wastewater treatment in the Pearl Delta: a balancing act

This paper reviews the current state of water pollution in the Pearl Delta, highlights the main problems, and discusses how private participation may serve a catalytic function in the important task of preventing the world's biggest economic boom turning into an environmental disaster.

A fuzzy regression analysis for the construction cost estimation of wastewater treatment plants (I) theoretical development

To achieve the water pollution control policy at both the national and local levels, engineering projects regarding the construction of sewer system and wastewater treatment plants have been launched in many regions. But the fuzzy structure of construction cost, where human estimation is influential, may result in an impediment of economic feasibility in decision making. Therefore, an understanding of the track of previous development of wastewater treatment in Taiwan, and of the related construction and operating cost structures of these facilities, becomes helpful in creating a valuable management strategy. This paper developes a new cost estimation approach: the modified fuzzy goal regression model. It specifically demonstrates how the fuzzy regression analyses can be established through the use of fuzzy goal programming techniques in a flexible manner.

The Development of Waste Water Treatment in the Finnish Pulp and Paper Industry

The recent development of Finnish pulp and paper industry external wastewater treatment has created positive results by reducing the oxygen consuming load (BOD7) of the recipients. This is due to the thirteen activated sludge plants and one anaerobic reactor which have been constructed during the last four years. The target values set in the form of suspended solids (SS) and BOD7 for 1985 (400 t BOD7/d) are expected to be achieved during 1987. Activated sludge plants have also created negative effects in the form of large amounts of surplus biological sludge and increased nutrient discharges, especially phosphorus which with reduced acute toxicity will increase the eutrophication of discharge areas. The share of activated sludge plants for the increased phosphorus discharges remains to be studied. The rapid increase started before the activated sludge plants started operation. In well operated activated sludge plant nutrient discharge is not increased. Although the specific water consumption and specific organic loads continuously decrease in pulp and paper production the increased production and more stringent requirements for pollution control prerequisite investments for external treatment. Therefore it is the time for efficient biological treatment plant construction and before 1995 a good number of mainly activated sludge plants will be constructed, for which time target values and some alternative guidelines to pollution control have been planned but not yet officially issued. Also requirements for CODCr, and total organic chlorine (TOCl) will be among the effluent quality criteria in the near future. When further requirements are issued the basis must be in the requirements of the biota which it is desired to live in the discharge areas. Much research is needed to find out how many of these requirements can be satisfied by modifications of present treatment processes. Thereafter the possibility of removing specific pollutants from the low volume fractions must be identified. The results of these studies must then be compared with the tertiary processes which can be added after the biological treatment plants which process the combined mill effluent. The problem must be regarded as a complex one because any substance removed from the wastewater will be found either in the sludge or in the air. The harmful compounds should be returned to normal ecological circulation or to the least harmful form and location in the most suitable waste stream.