Effluent outfalls are an important exit for pollutants discharged from the source flowing into environmental water bodies,as well as an important guarantee for the ecological environment of natural water bodies.In res...Effluent outfalls are an important exit for pollutants discharged from the source flowing into environmental water bodies,as well as an important guarantee for the ecological environment of natural water bodies.In response to main problems of large and diverse effluent outfalls,as well as their monitoring analysis,tracing and regulation in China,classification and regulation countermeasures were proposed based on the characteristics of effluent outfalls.It is suggested that a comprehensive management and control system should be built by improving the management and control system,upgrading monitoring techniques and strengthening social supervision and public education,so as to provide a scientific basis for the supervision and management of effluent outfalls in China and help promote the improvement of water quality and the sustainable development and utilization of water resources.展开更多
In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcom...In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.展开更多
The use of modeling and simulation has developed into a critical tool for the sustainable management of wastewater, especially when it comes to replicating the complex biochemical procedures required for fertilizer ef...The use of modeling and simulation has developed into a critical tool for the sustainable management of wastewater, especially when it comes to replicating the complex biochemical procedures required for fertilizer effluent treatment, which calls for a significant amount of wastewater-related data. The biological improvement of a urea fertilizer effluent via GPS* simulation was carried out in this work using a methodical process. Using established analytical techniques, temperature, total suspended solids (TSS), biochemical oxygen demand (BOD), total phosphorus (T/), chemical oxygen demand (COD), total nitrogen (TN), total nitrate (NO<sub>3</sub>), electric conductivity (EC), turbidity, residual chlorine, urea, NH<sub>3</sub>, and heavy metals (Cu, Cd, Cr, Pb, Ni, and Fe) were assessed. The research revealed that the measured values from the fertilizer factory outfall effluent had high concentrations of all the physicochemical water quality indicators, with the exception of TSS, PO<sub>4</sub><sup>-</sup>, SO<sub>4</sub><sup>-</sup>, and NO<sub>3</sub><sup>-</sup>. These concentrations are higher compared to the authorized limits or suggested values by the Federal Environmental Protection Agency (FEPA). To improve the therapy biologically, however, a modeling and simulation program (GPS-X, version 8.0) was used with the physicochemical information gathered from the studied sample. The results of the treated water simulation showed that the concentrations of BOD<sub>5</sub> and COD had been significantly reduced by 35% and 44%, respectively. Additionally, it was discovered that total phosphorus (TP), nitrate (N), and total nitrogen (TN) were all within the permitted FEPA limit. The results revealed good treatment performance of the wastewater with increasing concentration of acetic acid and sodium hydroxide. Hence, the results of this research work identify the need for proper treatment of fertilizer industry effluents prior to their release into the environment.展开更多
Pollution in recent times has become prevalent due to industrial expansion,hence,releasing pollutants into the environ-ment.Thus,this study aimed at investigating the effects of effluents from electroplating companies...Pollution in recent times has become prevalent due to industrial expansion,hence,releasing pollutants into the environ-ment.Thus,this study aimed at investigating the effects of effluents from electroplating companies on growth,heavy metals accumulation and concentrations in Amaranthus viridis.Seeds of A.viridis were obtained from the National Institute of Hor-ticulture,Ibadan.Loam soils were collected from Lagos State University and two samples of electroplating effluents were obtained from Oregun,Lagos.Seeds were sown,nursed,and transplanted in a uniform bucket filled with 5 kg loam soil and transplanted seedlings were treated with Effluent A(5 and 10%conc.)and Effluent B(5 and 10%conc.)and control respec-tively.Growth parameters such as plant height and so on were measured and plant samples harvested were analyzed for heavy metal concentrations using Atomic Absorption Spectrophotometer.Data collected were subjected to a one-way analysis of variance.Results revealed that Effluents A and B are highly acidic and above discharge limits.Also,the result revealed that 5%conc.of Effluents A and B had more effects on growth(p<0.05)of A.viridis across the harvests than 10%conc.in relation to control.This result showed that the effluent samples affect the growth rhythms of plants.Results further revealed vigorous–1–1 accumulation of the heavy metals:Zn(241.66µg kg±0.10 at third harvest in Effluent A:10%),Cu(68.25µg kg±0.23 at–1–1 first harvest in Effluent B:5%),Cr(500µg kg±0.90 in harvests at all concentrations.)and Ni(500µg kg±0.90 at third harvest in Effluent B:5%)and all these metals are far above the control and permissible limits of WHO/FAO recommenda-tions.From this study,it could be concluded that electroplating effluents had adverse effects on growth and increased metals’bioaccumulation in A.viridis.Therefore,the treatment of effluents to enhance an eco-friendly environment should be done.展开更多
There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds pe...There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds per day or pounds per unit of output).Concentration-based emission standard(e.g.milligrams per liter of wastewater) as one important form of environmental standard has not been given much attention.In this article,comparable estimates of their probable effect on enterprise pollution reduction will be developed for concentrationbased effluent standards,effluent taxes,and a combination of both.A linear simulation model is used to clearly and obviously compare the effects of effluent taxes and concentration-based standards within the same figure.With one detailed application to the paper industry,some enlightenment and conclusions-as well as the general applicability of these principles-are then provided:Under the same effluent tax rate,enterprises,groups,and industries that are cleaner will reduce more pollutants than those that have higher pollutant abatement costs.It is recommended that effluent taxes are set by avoiding cutting it even at one stroke and considering the feasibility of pollution-reducing technology in various industries.It is necessary to reduce MAC of enterprises to better stimulate enterprises' or industries' emission reduction by preferential measures,such as high tax rate coordinated by speeding up the depreciation of environmental protection equipment.展开更多
The overall objective of this study was to establish the effects of steel industrial effluent on Nairobi metropolitan water system and its impact to the society. The study sought to identify various types of wastes pr...The overall objective of this study was to establish the effects of steel industrial effluent on Nairobi metropolitan water system and its impact to the society. The study sought to identify various types of wastes produced by factories, assess how the waste generated is managed and disposed</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> examine the effects of effluent discharge on Nairobi River and finally propose mitigation measures. The research adopted a qualitative design and employed a number of methods: direct observations, document reviews to content analysis of the past studies, which in the end generated invaluable data. The study revealed that there are four categories of waste generated</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">:</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> solid waste, liquid waste, footbath chemicals as well as thermal wastes. It was also found that waste management in place w</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> not effective enough leading to water and soil pollution. Other causes of pollution were found out to emanate from gasses contamination to the air and chemicals used during steel processing. The findings will inform the community of the harmful effects of untreated water and how it impacts on their health and productivity. It will also help the stakeholders in the environmental conservation to articulate issues of policy and influence agenda setting in the national and sub-national levels.展开更多
Electrocoagulation process using high current intensity to treat palm oil mill effluent(POME) was investigated in this study.Various operating parameters such as electrolysis time, inter-electrode distance and initial...Electrocoagulation process using high current intensity to treat palm oil mill effluent(POME) was investigated in this study.Various operating parameters such as electrolysis time, inter-electrode distance and initial pH were carried out to determine the efficient process condition on the removal of chemical oxygen demand(COD),biological oxygen demand(BOD) and suspended solids(SS).The highest treatment was achieved at 50 min with the removal efficiencies for COD, BOD and SS obtained as 85%, 83%, and 84%, respectively.More than 50 min treatment showed the fluctuated trends of removal efficiencies which can be considered insignificant.The application of higher current resulted in higher removals of organics while the gas bubbles also assisted in removing the pollutant particles by floatation.In an inter-electrode distance study, the removal efficiency decreased when inter-electrode distance was either higher or lower than 10 mm due to the increase of solution resistance and the decrease of anode active surface area.In initial pH study, it was found that high removal efficiencies were achieved in slightly acidic POME sample rather than in neutral or basic condition.An electrocoagulation process by using the optimum operating parameters was able to remove COD, BOD and SS up to 95%, 94% and 96% respectively.The experimental results confirm that application of high current intensity in electrocoagulation provided high treatment efficiency at a reduced reaction time.展开更多
One of the challenges in effluent transport modeling in coastal tidal environments is the proper specification of initial dilution in connection with the far-field transport phenomena. An approach of external linkage ...One of the challenges in effluent transport modeling in coastal tidal environments is the proper specification of initial dilution in connection with the far-field transport phenomena. An approach of external linkage of far-field and near-field effluent transport models is presented, and applied to simulating the effluent transport in the Port Angeles Harbor, Washington in the Strait of Juan de Fuca. A near-field plume model was used to calculate the effluent initial dilution and a three-dimensional (3-D) hydrodynamic model was developed to simulate the tidal circulation and far-field effluent transport in the Port Angeles Harbor. The hydrodynamic model was driven by tides and surface winds. Observed water surface elevation and velocity data were used to calibrate the model over a period covering the neap-spring tidal cycle. The model was also validated with observed surface drogue trajectory data. The model successfully reproduced the tidal dynamics in the study area and good agreements between model results and observed data were obtained. It is demonstrated that the linkage between the near-field and far-field models in effluent transport modeling can be achieved through iteratively adjusting the model grid sizes such that the dilution ratio and effluent concentration in the circulation model grid cell match the concentration calculated by the near-field plume model.展开更多
The paper has focused on the challenges/impacts of tannery effluent and evaluates the alternative treatment options used to treat, recover or recycle chromium from the waste water. The paper was done entirely on secon...The paper has focused on the challenges/impacts of tannery effluent and evaluates the alternative treatment options used to treat, recover or recycle chromium from the waste water. The paper was done entirely on secondary data by consulting literature sources including scientific journals, chapters of books, conference report papers and websites. The results of this review paper indicated that chromium is highly toxic and carcinogenic to human beings, animals, plants and the general environment (soil and water sediment). It is found out that chrome is the primary threat when ever tanning industry comes in to practice. Though many treatment options were evaluated to prevent its consequence on the environment, neither of them could achieve to treat or recover chrome 100%. Treatment options are either;inef-ficient, complicated, energy demanding, costly or applicable to a certain parts of the world due to technology or skilled man power demand. Therefore, to tackle this serious challenge stringent environmental regulation with law enforce-ment has to be exercised to use better treatment system which is widely applicable. Polluters must also know the envi-ronmental cost of their industry and treated according to polluter pay or precautionary principles. Moreover, the gen-eral public has to be aware of it and all concerned organizations and governments has to work hand in hand to reach zero discharge level or at least to attain the EPA chrome discharge展开更多
Following the need for the use of environmentally friendly, renewable resource in industrial processes, this work explores the potential of an effective application in pilot scale of Afzelia bella seed as a coag-flocc...Following the need for the use of environmentally friendly, renewable resource in industrial processes, this work explores the potential of an effective application in pilot scale of Afzelia bella seed as a coag-flocculant. The study evaluates the coag-flocculation efficiency and functional kinetic parameter response to varying pH and dosage of coal washery effluent and ABC respectively. The maximum coag-flocculation performance is recorded at rate constant, K of 3.3333 x 10-3m3/kg.s, dosage of (0.3 and 0.2kg/m3);pH of 2 and coagulation period, τ1/2of 28.1216 s while the minimum is recorded at K of 1.6667 x 10-4m3/kg.s, dosage of 0.2kg/m3, pH of 10 and τ1/2 of 562.365 s. The least value of coag-flocculation efficiency, E (%)>89.00. Simulated and unsimulated values of rate constants Ks and K respectively are in close agreement, validating the concept of perikinetics. The potential of ABC as an effective organic coag-flocculant has been established. The results confirm that theory of rapid coagflocculation holds for the aggregation of coal washery effluent using ABC and at the conditions of the experiment.展开更多
The components of the effluent from the chemical pretreatment of poplar alkaline peroxide mechanical pulp(APMP) were analyzed in this study. The main dissolved organics were low-molecular weight(LMW) lignin, oligosacc...The components of the effluent from the chemical pretreatment of poplar alkaline peroxide mechanical pulp(APMP) were analyzed in this study. The main dissolved organics were low-molecular weight(LMW) lignin, oligosaccharides, and monosaccharides. The lignin and sugar concentrations in the effluent obtained using different chemical pretreatment conditions and chemical dosages were analyzed using ultraviolet(UV) spectroscopy. This analysis provided a theoretical basis for the subsequent treatment and utilization of APMP effluent. The experimental results showed that the dosages of Na OH, H_2O_2, and Na_2 SiO_3 in the chemical pretreatment process affected the lignin and sugar concentrations in the effluent and that different chemicals had differing degrees of influence. The degree of influence exhibited the following order: Na OH>H_2O_2>Na_2SiO_3. More specifically, the dosages of Na OH and H_2O_2 had stronger influences on the lignin and sugar concentrations than that of Na_2 SiO_3. Indeed, the Na_2 SiO_3 dosage hardly affected the lignin and sugar concentrations in the effluent, but Na_2 SiO_3 could stabilize the chemical pretreatment system and improve the reactive efficiency of Na OH and H_2O_2. The pretreatment temperature and time also affected the organic components, and the influence of the temperature was stronger than that of time.展开更多
The presence of polycyclic aromatic hydrocarbons (PAH) in produced water is of environmental concern due to their toxic properties. PAH analysis in complex samples requires pre-treatment to enrich the fraction con- ta...The presence of polycyclic aromatic hydrocarbons (PAH) in produced water is of environmental concern due to their toxic properties. PAH analysis in complex samples requires pre-treatment to enrich the fraction con- taining analytes, and eliminate matrix interferences. The objective of this work was to develop and validate an analytical methodology for determination of PAH in produced water, using solid phase extraction (SPE) and analysis by gas chromatography with flame ionization detection (GC-FID). Average recoveries of PAH from produced water enriched at two concentration levels varied from 30.9% for naphthalene to 119.1% for chrysene (RSD between 3.8% and 22.2%). The linear range was between 0.5 and 50.0 μg?mL–1, with regres- sion coefficients better than 0.998. Detection limits were between 0.01 and 0.04 μg?L–1, and quantitation lim- its were between 0.05 and 0.16 μg?L–1. The validated method was applied to samples of produced water treated for disposal, in which concentrations varied from 3.5 μg?L–1 for phenanthrene to 44.3 μg?L–1 for naphthalene ( = 177.7 μg?L–1). The method was also applied to seawater samples, in which 13 PAH compounds were detected ( = 60.27 μg?L–1), probably derived from pyrogenic sources.展开更多
Oil palm currently occupies the largest acreage of farm land in Malaysia. In 2011, the production of palm oil in Malaysia was recorded as 19.8 million tons which has led to a huge amount of wastewater known as palm oi...Oil palm currently occupies the largest acreage of farm land in Malaysia. In 2011, the production of palm oil in Malaysia was recorded as 19.8 million tons which has led to a huge amount of wastewater known as palm oil mill effluent (POME). This work focuses on the ponding system which acts as wastewater treatment plant in order to treat POME. The conventional ponding system applied in mills consists of a series of seven ponds. The maintenance costs of the pond are expensive thus study of alternative methods is needed. POME treatment using zeolite shows a potential to overcome the problem. Samples collected from selected ponds are tested and analyzed using water analyzer method. Result from adsorption by zeolite shows a significant reduction of COD, BOD, Fe, Zn, Mn and turbidity. This shows that zeolite is highly potential to be applied as adsorbent in the POME treatment plants. The results here may lead to lower maintenance cost, lower quantity of treatment ponds and lesser land occupied for the treatment of POME in Malaysia.展开更多
The study aims to investigate the current extent of physicochemical parameters and heavy metal contamination in the effluent of the Jaganpur sewage treatment plant (STP), Dayalbagh, Agra India. Majority of the nearby ...The study aims to investigate the current extent of physicochemical parameters and heavy metal contamination in the effluent of the Jaganpur sewage treatment plant (STP), Dayalbagh, Agra India. Majority of the nearby farmers have access to use of STP effluent in irrigation purposes for growing major edible crops. The problems of using STP effluent for irrigation purpose, continuous water quality analysis required. To check the quality of irrigation water, substantial physicochemical parameters accordance to Indian Standards (IS-Reaffirmed 2002/2003) analysed to calculate Sodium absorption ratio (SAR) and Residual sodium carbonate (RSC). To estimate the heavy metal pollution index (HPI) and metal quality index (MQI), toxic Heavy metals such as As, Cr, Mn, Fe, Ni, Cu, Zn, Pd, Cd, Co, and B also determined in the STP effluent with an AAS and results verified with ICP-OES against certified standards. The high value of SAR (range 13 to 20) and RSC (range -10 to 11) in STP effluent exceeded the permissible limit for irrigation purpose. On the other hand, HPI and MQI values (1692.4 and 58.1, respectively) show that high metal contamination mainly due to industrial and domestic wastewater does not treat appropriately in the sewage treatment plant. Thus it is suggested that further studies are carried out on the STP effluents to improve the water quality through proper treatment. Treated wastewater used for irrigation purposes needs to analyse the contamination like heavy metals and pinpoint the pollution sources.展开更多
The growth performance,nutrient removal,lipid accumulation and morphological changes of Cyanobacterium aponinum OUC1 and Scenedesmus obliquus which were cultured in secondary effluents from two wastewater treatment pl...The growth performance,nutrient removal,lipid accumulation and morphological changes of Cyanobacterium aponinum OUC1 and Scenedesmus obliquus which were cultured in secondary effluents from two wastewater treatment plants:Tuandao Wastewater Treatment Plant(ETD)and Licun River Wastewater Treatment Plant(ELR)were investigated.The results showed that both C.aponinum OUC1 and S.obliquus have superior growth performances in both undiluted effluents,while the better of them was that in ETD effluent,with cell densities of C.aponinum OUC1 and S.obliquus increased by 159%and 66%over that of BG11(control),respectively.Regarding nutrient removal,S.obliquus could completely remove inorganic phosphorus,and decrease ammonia nitrogen in ETD effluent by 81%.In addition,both C.aponinum OUC1 and S.obliquus cultivated in ETD exhibited extraordinary potential for biofuel production,increasing lipid productivities by 133%and 89%of that cultivated in ELR,respectively.As to ultrastructural changes,the differences in the lipoidal globules and glycogen granules of S.obliquus and C.aponinum OUC1 among the ETD and ELR treatments were mostly related to phosphorus limitations.The findings from this research reveal the probability using the secondary effluents as cultivation media to enhance algal biomass,nutrient removal and lipid productivity.展开更多
The aim of the present work was to isolate <em>Bacillus</em> spp. With high lipase activity;to characterize the isolates using both biochemical and molecular methods;to produce lipase using <em>Bacil...The aim of the present work was to isolate <em>Bacillus</em> spp. With high lipase activity;to characterize the isolates using both biochemical and molecular methods;to produce lipase using <em>Bacillus</em> isolates and to study the biochemical and biophysical characteristics of the produced lipase. Sixty five <em>Bacillus</em> isolates were isolated from soil 20 isolates from guar field soil (G), 15 isolates from Abusabein field soil (B), 15 isolates from sun flower field soil (S) and 15 isolates from oil effluent (O). Lipase producing isolates were screened;a Chromogenic plate’s method was used. Enzyme activity was quantitatively assayed. Lipase production under submerged fermentation (SMF) conditions using a production medium that contained metal salts, Tween-20 and olive oil as substrate at different period 24, 48, 72 and 96 h, the optimum pH, temperature for lipase activity was determinated and kinetics as well. The isolates showed the highest lipase activity which was identified as Bacillus sp. The optimum pH, temperature, thermostability and kinetic of the produced enzymes were found in three isolates G14, O1 and B10 with the highest enzyme activity and best stability. The isolates G14, O1 and B10 revealed the highest lipase activity of 63.4, 41.2 and 28.3 U/ml, respectively. The results showed optimum pH of the lipase activity from isolates G14, O1 and B10 8.0, 6.0 and 6.0 and the optimum temperature 40, 60 and 75<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span></span></span>C, respectively. Lipase enzymes from isolates O1 and B10 were found to be more thermostable after incubation time for 120 min at 90<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span></span></span>C. The V<sub>max</sub> and K<sub>m</sub> values of lipase for isolates G14, OI and B10 were 17.6, 135 and 24.4 μmole<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span></span></span>min<span style="white-space:nowrap;"><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span></sup></span><sup>1</sup> and 1.3, 1.6 and 0.681 mM, respectively. According to these results <em>Bacillus</em> spp. with high lipase activity and thermostability can be used to promote food, pharmaceuticals, paper, detergents agrochemicals industries and pollution control in Sudan.展开更多
Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to deter...Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to determine the optimum incubation period of purple non-sulphur bacterium (PNSB) in reduction of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in settled POME and to determine the dry cell weight, TN, TP and cell yield of PNSB. Pure isolate of Rhodobacter sphaeroides strain UMSFW1 was cultured in settled POME under anaerobic condition at 2500 lux illumination on light intensity at a temperature of 30°C ± 2°C for 144-h. Parameters such as COD (mg/L), dry cell biomass (g/L), TP (mg/L) and TN (mg/L) in settled POME and bacterial cells were analyzed. A total reduction of TN (43.9%) in settled POME and a total increase of TN (43.2%) in bacterial cell were recorded at the end of experiment. At the same time the reduction of 51.5% chemical oxygen demand was determined from the POME. The highest dry cell weight of 2.44 g/L with cell yield 0.39 (mg/cell/mg COD) was achieved at the end of experiment. A total 24.7% of TP reduction in settled POME was achieved in 144-h culture, but while a maximum 10% of TP in bacterial cell was achieved in 48-h culture. This study shows that PNSB Rhodobacter sphaeroides strain UMSFW1 grows well by using settled POME as substrate and is capable to remove TN in the settled POME and assimilate into bacterial biomass. This study could provide us a further insight in the nutrient removal and COD removal in the bioremediation process by bacterium Rhodobacter sphaeroides strain UMSFW1.展开更多
A chromate-removing strain was isolated from spent chrome effluent and identified as Bacillus circulans strain MN1. The isolated strain was studied for resistance to Cr (VI) and its ability to remove Cr (VI). The stra...A chromate-removing strain was isolated from spent chrome effluent and identified as Bacillus circulans strain MN1. The isolated strain was studied for resistance to Cr (VI) and its ability to remove Cr (VI). The strain was found to tolerate Cr (VI) concentration as high as 4500 mg/L, but the cells growth was heavily influenced when initial Cr (VI) concentration was increased between 1110 mg/L and 4500 mg/L while Cr(VI) at 500 mg/L to 1110 mg/L did not suppressed the cells growth. The experiments also demonstrated that the cells removed toxic Cr (VI) more efficiently at 30?C compared with that at 25?C and 35?C. The optimum initial pH for Cr (VI) removal was 5.6 and final pH values of 5.1-5.6 were observed for initial pH 5.2-5.7.展开更多
This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent and the consequent solution of the problem by installation of effluent treatment plant. Though the medium a...This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent and the consequent solution of the problem by installation of effluent treatment plant. Though the medium and small-scale industrial activities have a positive impact on the economy of our country, the increasing industrialization is contributing severe pollution to the environment by the toxic waste discharge. The liquid effluents from industries are causing a major havoc to the environment, ecology, agriculture, aquaculture and public health since the development of textile industries in the country. So, it is time to give a pause to the pollution and phase it out gradually to protect the river system. It had become a prerequisite to set up ETP in each industrial establishment, particularly at dyeing industries that were discharging huge amount of liquid waste to the rivers every day. Since the highest number of factories is of textile category and these types of factories play a major role in polluting the nature, Government’s main focus is on the textile mills and industries related to textile. But, for the successful implementation of ETPs, industry owners will have to be socially responsible and at the same time, government should provide the factory owners with logistic supports and relaxed timeframe to set up ETPs.展开更多
Dyes mostly used in the textile industry end up in their wastewater. The treatment of textile effluent has become necessary because of its associated environmental and health problems. In this study, five bacterial is...Dyes mostly used in the textile industry end up in their wastewater. The treatment of textile effluent has become necessary because of its associated environmental and health problems. In this study, five bacterial isolates were obtained from textile effluent. The isolated bacteria were used to decolourise effluent samples in a time-dependent manner and the change in colour was observed using an Ultraviolet-visible spectrophotometer. After 24 hours, decolourisation efficiencies of the five isolates were calculated and the highest decolourisation efficiency (78.5%) was observed with one of the isolates (E12). Isolate E23 recorded 64.7% followed by isolate E9 (62.0%) and E21 (53.7%). Isolate E19 had the lowest decolourisation efficiency (2.6%). The isolated bacteria were identified with E9 as <i>Aeromonas hydrophilia</i>, E12 as <i>Aeromonas hydrophilia</i>, E19 as <i>Pseudomonas aeruginosa</i>, E21 as <i>Aeromonas hydrophilia</i> and E23 as <i>Pseudomonas fluorescens</i>. To achieve a decolourisation efficiency of 78.5%, 25 ml of textile wastewater should be inoculated with 1 ml of the isolate (E12) culture. Thus, Isolate E12 (<i>Aeromonas hydrophilia</i>) is considered a promising candidate for biological textile wastewater treatment followed by isolate E23 (<i>Pseudomonas fluorescens</i>).展开更多
文摘Effluent outfalls are an important exit for pollutants discharged from the source flowing into environmental water bodies,as well as an important guarantee for the ecological environment of natural water bodies.In response to main problems of large and diverse effluent outfalls,as well as their monitoring analysis,tracing and regulation in China,classification and regulation countermeasures were proposed based on the characteristics of effluent outfalls.It is suggested that a comprehensive management and control system should be built by improving the management and control system,upgrading monitoring techniques and strengthening social supervision and public education,so as to provide a scientific basis for the supervision and management of effluent outfalls in China and help promote the improvement of water quality and the sustainable development and utilization of water resources.
文摘In the present study, polyethersulfone based nanohybrid membranes were effectively fabricated by incorporating graphene oxide(GO) and hydrotalcite(HT) nanosheets into the membrane structure. HT was prepared to overcome the irreversible agglomeration behavior of GO at a high concentration which affects the performance of the membranes. In particular, the shedding of HT in formamide provides a two-dimensional nanosheet with a higher positive charge density to prevent the restacking of GO nanosheets. Here, exfoliated GO and HT with different combinations(1:1, 1:2 and 1:3) were infused in the membrane matrix to treat lead-acid battery effluent effectively. Finally, the hybrid membranes were characterized for hydrophilicity, mechanical strength and pure water flux. In combination with the superior properties of GO and HT, the prepared hybrid membranes can be used as effectively to improve the separation and permeation performance. The phase inversion process eliminated the leaching of nanoparticles from the membrane matrix. The reusability of the hybrid membrane was achieved using0.1 mol·L^(-1)NaOH solution and reused without significant reduction in lead removal efficiency. The cost analysis of the membrane was also estimated from the lab study. Therefore, the present study suggested the selective and sustainable treatment of lead from a real-life effluent.
文摘The use of modeling and simulation has developed into a critical tool for the sustainable management of wastewater, especially when it comes to replicating the complex biochemical procedures required for fertilizer effluent treatment, which calls for a significant amount of wastewater-related data. The biological improvement of a urea fertilizer effluent via GPS* simulation was carried out in this work using a methodical process. Using established analytical techniques, temperature, total suspended solids (TSS), biochemical oxygen demand (BOD), total phosphorus (T/), chemical oxygen demand (COD), total nitrogen (TN), total nitrate (NO<sub>3</sub>), electric conductivity (EC), turbidity, residual chlorine, urea, NH<sub>3</sub>, and heavy metals (Cu, Cd, Cr, Pb, Ni, and Fe) were assessed. The research revealed that the measured values from the fertilizer factory outfall effluent had high concentrations of all the physicochemical water quality indicators, with the exception of TSS, PO<sub>4</sub><sup>-</sup>, SO<sub>4</sub><sup>-</sup>, and NO<sub>3</sub><sup>-</sup>. These concentrations are higher compared to the authorized limits or suggested values by the Federal Environmental Protection Agency (FEPA). To improve the therapy biologically, however, a modeling and simulation program (GPS-X, version 8.0) was used with the physicochemical information gathered from the studied sample. The results of the treated water simulation showed that the concentrations of BOD<sub>5</sub> and COD had been significantly reduced by 35% and 44%, respectively. Additionally, it was discovered that total phosphorus (TP), nitrate (N), and total nitrogen (TN) were all within the permitted FEPA limit. The results revealed good treatment performance of the wastewater with increasing concentration of acetic acid and sodium hydroxide. Hence, the results of this research work identify the need for proper treatment of fertilizer industry effluents prior to their release into the environment.
文摘Pollution in recent times has become prevalent due to industrial expansion,hence,releasing pollutants into the environ-ment.Thus,this study aimed at investigating the effects of effluents from electroplating companies on growth,heavy metals accumulation and concentrations in Amaranthus viridis.Seeds of A.viridis were obtained from the National Institute of Hor-ticulture,Ibadan.Loam soils were collected from Lagos State University and two samples of electroplating effluents were obtained from Oregun,Lagos.Seeds were sown,nursed,and transplanted in a uniform bucket filled with 5 kg loam soil and transplanted seedlings were treated with Effluent A(5 and 10%conc.)and Effluent B(5 and 10%conc.)and control respec-tively.Growth parameters such as plant height and so on were measured and plant samples harvested were analyzed for heavy metal concentrations using Atomic Absorption Spectrophotometer.Data collected were subjected to a one-way analysis of variance.Results revealed that Effluents A and B are highly acidic and above discharge limits.Also,the result revealed that 5%conc.of Effluents A and B had more effects on growth(p<0.05)of A.viridis across the harvests than 10%conc.in relation to control.This result showed that the effluent samples affect the growth rhythms of plants.Results further revealed vigorous–1–1 accumulation of the heavy metals:Zn(241.66µg kg±0.10 at third harvest in Effluent A:10%),Cu(68.25µg kg±0.23 at–1–1 first harvest in Effluent B:5%),Cr(500µg kg±0.90 in harvests at all concentrations.)and Ni(500µg kg±0.90 at third harvest in Effluent B:5%)and all these metals are far above the control and permissible limits of WHO/FAO recommenda-tions.From this study,it could be concluded that electroplating effluents had adverse effects on growth and increased metals’bioaccumulation in A.viridis.Therefore,the treatment of effluents to enhance an eco-friendly environment should be done.
基金supported by Beijing Natural Science Foundation(9154036)"Water Pollution Control Strategy and Decision Support Platform"[grant No.2009ZX07631-02-03]"Water Pollution Accident Damage Assessment Technology Research[grant No.201309060]"
文摘There are numerous studies comparing different kinds of environmental taxes and standards.However,forms of environmental standards focused by former researchers are usually quantitybased limits/standards(e.g.pounds per day or pounds per unit of output).Concentration-based emission standard(e.g.milligrams per liter of wastewater) as one important form of environmental standard has not been given much attention.In this article,comparable estimates of their probable effect on enterprise pollution reduction will be developed for concentrationbased effluent standards,effluent taxes,and a combination of both.A linear simulation model is used to clearly and obviously compare the effects of effluent taxes and concentration-based standards within the same figure.With one detailed application to the paper industry,some enlightenment and conclusions-as well as the general applicability of these principles-are then provided:Under the same effluent tax rate,enterprises,groups,and industries that are cleaner will reduce more pollutants than those that have higher pollutant abatement costs.It is recommended that effluent taxes are set by avoiding cutting it even at one stroke and considering the feasibility of pollution-reducing technology in various industries.It is necessary to reduce MAC of enterprises to better stimulate enterprises' or industries' emission reduction by preferential measures,such as high tax rate coordinated by speeding up the depreciation of environmental protection equipment.
文摘The overall objective of this study was to establish the effects of steel industrial effluent on Nairobi metropolitan water system and its impact to the society. The study sought to identify various types of wastes produced by factories, assess how the waste generated is managed and disposed</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> examine the effects of effluent discharge on Nairobi River and finally propose mitigation measures. The research adopted a qualitative design and employed a number of methods: direct observations, document reviews to content analysis of the past studies, which in the end generated invaluable data. The study revealed that there are four categories of waste generated</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">:</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> solid waste, liquid waste, footbath chemicals as well as thermal wastes. It was also found that waste management in place w</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> not effective enough leading to water and soil pollution. Other causes of pollution were found out to emanate from gasses contamination to the air and chemicals used during steel processing. The findings will inform the community of the harmful effects of untreated water and how it impacts on their health and productivity. It will also help the stakeholders in the environmental conservation to articulate issues of policy and influence agenda setting in the national and sub-national levels.
基金Supported by Universiti Malaysia Pahang Research Grant(RDU1803143)
文摘Electrocoagulation process using high current intensity to treat palm oil mill effluent(POME) was investigated in this study.Various operating parameters such as electrolysis time, inter-electrode distance and initial pH were carried out to determine the efficient process condition on the removal of chemical oxygen demand(COD),biological oxygen demand(BOD) and suspended solids(SS).The highest treatment was achieved at 50 min with the removal efficiencies for COD, BOD and SS obtained as 85%, 83%, and 84%, respectively.More than 50 min treatment showed the fluctuated trends of removal efficiencies which can be considered insignificant.The application of higher current resulted in higher removals of organics while the gas bubbles also assisted in removing the pollutant particles by floatation.In an inter-electrode distance study, the removal efficiency decreased when inter-electrode distance was either higher or lower than 10 mm due to the increase of solution resistance and the decrease of anode active surface area.In initial pH study, it was found that high removal efficiencies were achieved in slightly acidic POME sample rather than in neutral or basic condition.An electrocoagulation process by using the optimum operating parameters was able to remove COD, BOD and SS up to 95%, 94% and 96% respectively.The experimental results confirm that application of high current intensity in electrocoagulation provided high treatment efficiency at a reduced reaction time.
文摘One of the challenges in effluent transport modeling in coastal tidal environments is the proper specification of initial dilution in connection with the far-field transport phenomena. An approach of external linkage of far-field and near-field effluent transport models is presented, and applied to simulating the effluent transport in the Port Angeles Harbor, Washington in the Strait of Juan de Fuca. A near-field plume model was used to calculate the effluent initial dilution and a three-dimensional (3-D) hydrodynamic model was developed to simulate the tidal circulation and far-field effluent transport in the Port Angeles Harbor. The hydrodynamic model was driven by tides and surface winds. Observed water surface elevation and velocity data were used to calibrate the model over a period covering the neap-spring tidal cycle. The model was also validated with observed surface drogue trajectory data. The model successfully reproduced the tidal dynamics in the study area and good agreements between model results and observed data were obtained. It is demonstrated that the linkage between the near-field and far-field models in effluent transport modeling can be achieved through iteratively adjusting the model grid sizes such that the dilution ratio and effluent concentration in the circulation model grid cell match the concentration calculated by the near-field plume model.
文摘The paper has focused on the challenges/impacts of tannery effluent and evaluates the alternative treatment options used to treat, recover or recycle chromium from the waste water. The paper was done entirely on secondary data by consulting literature sources including scientific journals, chapters of books, conference report papers and websites. The results of this review paper indicated that chromium is highly toxic and carcinogenic to human beings, animals, plants and the general environment (soil and water sediment). It is found out that chrome is the primary threat when ever tanning industry comes in to practice. Though many treatment options were evaluated to prevent its consequence on the environment, neither of them could achieve to treat or recover chrome 100%. Treatment options are either;inef-ficient, complicated, energy demanding, costly or applicable to a certain parts of the world due to technology or skilled man power demand. Therefore, to tackle this serious challenge stringent environmental regulation with law enforce-ment has to be exercised to use better treatment system which is widely applicable. Polluters must also know the envi-ronmental cost of their industry and treated according to polluter pay or precautionary principles. Moreover, the gen-eral public has to be aware of it and all concerned organizations and governments has to work hand in hand to reach zero discharge level or at least to attain the EPA chrome discharge
文摘Following the need for the use of environmentally friendly, renewable resource in industrial processes, this work explores the potential of an effective application in pilot scale of Afzelia bella seed as a coag-flocculant. The study evaluates the coag-flocculation efficiency and functional kinetic parameter response to varying pH and dosage of coal washery effluent and ABC respectively. The maximum coag-flocculation performance is recorded at rate constant, K of 3.3333 x 10-3m3/kg.s, dosage of (0.3 and 0.2kg/m3);pH of 2 and coagulation period, τ1/2of 28.1216 s while the minimum is recorded at K of 1.6667 x 10-4m3/kg.s, dosage of 0.2kg/m3, pH of 10 and τ1/2 of 562.365 s. The least value of coag-flocculation efficiency, E (%)>89.00. Simulated and unsimulated values of rate constants Ks and K respectively are in close agreement, validating the concept of perikinetics. The potential of ABC as an effective organic coag-flocculant has been established. The results confirm that theory of rapid coagflocculation holds for the aggregation of coal washery effluent using ABC and at the conditions of the experiment.
基金financial support provided by the Guangxi Science Foundation for the Youth (Grant No.2014GXNSFBA118060)the National Science Foundation of China (Grant Nos.31270627,31370580,and 31470602)the Provincial Key Scientific and Technological Project (2014zzcx09101)
文摘The components of the effluent from the chemical pretreatment of poplar alkaline peroxide mechanical pulp(APMP) were analyzed in this study. The main dissolved organics were low-molecular weight(LMW) lignin, oligosaccharides, and monosaccharides. The lignin and sugar concentrations in the effluent obtained using different chemical pretreatment conditions and chemical dosages were analyzed using ultraviolet(UV) spectroscopy. This analysis provided a theoretical basis for the subsequent treatment and utilization of APMP effluent. The experimental results showed that the dosages of Na OH, H_2O_2, and Na_2 SiO_3 in the chemical pretreatment process affected the lignin and sugar concentrations in the effluent and that different chemicals had differing degrees of influence. The degree of influence exhibited the following order: Na OH>H_2O_2>Na_2SiO_3. More specifically, the dosages of Na OH and H_2O_2 had stronger influences on the lignin and sugar concentrations than that of Na_2 SiO_3. Indeed, the Na_2 SiO_3 dosage hardly affected the lignin and sugar concentrations in the effluent, but Na_2 SiO_3 could stabilize the chemical pretreatment system and improve the reactive efficiency of Na OH and H_2O_2. The pretreatment temperature and time also affected the organic components, and the influence of the temperature was stronger than that of time.
文摘The presence of polycyclic aromatic hydrocarbons (PAH) in produced water is of environmental concern due to their toxic properties. PAH analysis in complex samples requires pre-treatment to enrich the fraction con- taining analytes, and eliminate matrix interferences. The objective of this work was to develop and validate an analytical methodology for determination of PAH in produced water, using solid phase extraction (SPE) and analysis by gas chromatography with flame ionization detection (GC-FID). Average recoveries of PAH from produced water enriched at two concentration levels varied from 30.9% for naphthalene to 119.1% for chrysene (RSD between 3.8% and 22.2%). The linear range was between 0.5 and 50.0 μg?mL–1, with regres- sion coefficients better than 0.998. Detection limits were between 0.01 and 0.04 μg?L–1, and quantitation lim- its were between 0.05 and 0.16 μg?L–1. The validated method was applied to samples of produced water treated for disposal, in which concentrations varied from 3.5 μg?L–1 for phenanthrene to 44.3 μg?L–1 for naphthalene ( = 177.7 μg?L–1). The method was also applied to seawater samples, in which 13 PAH compounds were detected ( = 60.27 μg?L–1), probably derived from pyrogenic sources.
文摘Oil palm currently occupies the largest acreage of farm land in Malaysia. In 2011, the production of palm oil in Malaysia was recorded as 19.8 million tons which has led to a huge amount of wastewater known as palm oil mill effluent (POME). This work focuses on the ponding system which acts as wastewater treatment plant in order to treat POME. The conventional ponding system applied in mills consists of a series of seven ponds. The maintenance costs of the pond are expensive thus study of alternative methods is needed. POME treatment using zeolite shows a potential to overcome the problem. Samples collected from selected ponds are tested and analyzed using water analyzer method. Result from adsorption by zeolite shows a significant reduction of COD, BOD, Fe, Zn, Mn and turbidity. This shows that zeolite is highly potential to be applied as adsorbent in the POME treatment plants. The results here may lead to lower maintenance cost, lower quantity of treatment ponds and lesser land occupied for the treatment of POME in Malaysia.
文摘The study aims to investigate the current extent of physicochemical parameters and heavy metal contamination in the effluent of the Jaganpur sewage treatment plant (STP), Dayalbagh, Agra India. Majority of the nearby farmers have access to use of STP effluent in irrigation purposes for growing major edible crops. The problems of using STP effluent for irrigation purpose, continuous water quality analysis required. To check the quality of irrigation water, substantial physicochemical parameters accordance to Indian Standards (IS-Reaffirmed 2002/2003) analysed to calculate Sodium absorption ratio (SAR) and Residual sodium carbonate (RSC). To estimate the heavy metal pollution index (HPI) and metal quality index (MQI), toxic Heavy metals such as As, Cr, Mn, Fe, Ni, Cu, Zn, Pd, Cd, Co, and B also determined in the STP effluent with an AAS and results verified with ICP-OES against certified standards. The high value of SAR (range 13 to 20) and RSC (range -10 to 11) in STP effluent exceeded the permissible limit for irrigation purpose. On the other hand, HPI and MQI values (1692.4 and 58.1, respectively) show that high metal contamination mainly due to industrial and domestic wastewater does not treat appropriately in the sewage treatment plant. Thus it is suggested that further studies are carried out on the STP effluents to improve the water quality through proper treatment. Treated wastewater used for irrigation purposes needs to analyse the contamination like heavy metals and pinpoint the pollution sources.
基金This work was supported by the National Marine Hazard Mitigation Service,Ministry of Natural Resources of the People’s Republic of China through its Commissioned Research Scheme(No.2019005AC).
文摘The growth performance,nutrient removal,lipid accumulation and morphological changes of Cyanobacterium aponinum OUC1 and Scenedesmus obliquus which were cultured in secondary effluents from two wastewater treatment plants:Tuandao Wastewater Treatment Plant(ETD)and Licun River Wastewater Treatment Plant(ELR)were investigated.The results showed that both C.aponinum OUC1 and S.obliquus have superior growth performances in both undiluted effluents,while the better of them was that in ETD effluent,with cell densities of C.aponinum OUC1 and S.obliquus increased by 159%and 66%over that of BG11(control),respectively.Regarding nutrient removal,S.obliquus could completely remove inorganic phosphorus,and decrease ammonia nitrogen in ETD effluent by 81%.In addition,both C.aponinum OUC1 and S.obliquus cultivated in ETD exhibited extraordinary potential for biofuel production,increasing lipid productivities by 133%and 89%of that cultivated in ELR,respectively.As to ultrastructural changes,the differences in the lipoidal globules and glycogen granules of S.obliquus and C.aponinum OUC1 among the ETD and ELR treatments were mostly related to phosphorus limitations.The findings from this research reveal the probability using the secondary effluents as cultivation media to enhance algal biomass,nutrient removal and lipid productivity.
文摘The aim of the present work was to isolate <em>Bacillus</em> spp. With high lipase activity;to characterize the isolates using both biochemical and molecular methods;to produce lipase using <em>Bacillus</em> isolates and to study the biochemical and biophysical characteristics of the produced lipase. Sixty five <em>Bacillus</em> isolates were isolated from soil 20 isolates from guar field soil (G), 15 isolates from Abusabein field soil (B), 15 isolates from sun flower field soil (S) and 15 isolates from oil effluent (O). Lipase producing isolates were screened;a Chromogenic plate’s method was used. Enzyme activity was quantitatively assayed. Lipase production under submerged fermentation (SMF) conditions using a production medium that contained metal salts, Tween-20 and olive oil as substrate at different period 24, 48, 72 and 96 h, the optimum pH, temperature for lipase activity was determinated and kinetics as well. The isolates showed the highest lipase activity which was identified as Bacillus sp. The optimum pH, temperature, thermostability and kinetic of the produced enzymes were found in three isolates G14, O1 and B10 with the highest enzyme activity and best stability. The isolates G14, O1 and B10 revealed the highest lipase activity of 63.4, 41.2 and 28.3 U/ml, respectively. The results showed optimum pH of the lipase activity from isolates G14, O1 and B10 8.0, 6.0 and 6.0 and the optimum temperature 40, 60 and 75<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span></span></span>C, respectively. Lipase enzymes from isolates O1 and B10 were found to be more thermostable after incubation time for 120 min at 90<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">˚</span></span></span></span>C. The V<sub>max</sub> and K<sub>m</sub> values of lipase for isolates G14, OI and B10 were 17.6, 135 and 24.4 μmole<span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">∙</span></span></span></span>min<span style="white-space:nowrap;"><sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span></span></span></sup></span><sup>1</sup> and 1.3, 1.6 and 0.681 mM, respectively. According to these results <em>Bacillus</em> spp. with high lipase activity and thermostability can be used to promote food, pharmaceuticals, paper, detergents agrochemicals industries and pollution control in Sudan.
文摘Sustainable use of palm oil mill effluent (POME) has been the major focus in the recent development in palm oil industry due to the fact that environmental issue brought by POME. The purpose of this study was to determine the optimum incubation period of purple non-sulphur bacterium (PNSB) in reduction of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in settled POME and to determine the dry cell weight, TN, TP and cell yield of PNSB. Pure isolate of Rhodobacter sphaeroides strain UMSFW1 was cultured in settled POME under anaerobic condition at 2500 lux illumination on light intensity at a temperature of 30°C ± 2°C for 144-h. Parameters such as COD (mg/L), dry cell biomass (g/L), TP (mg/L) and TN (mg/L) in settled POME and bacterial cells were analyzed. A total reduction of TN (43.9%) in settled POME and a total increase of TN (43.2%) in bacterial cell were recorded at the end of experiment. At the same time the reduction of 51.5% chemical oxygen demand was determined from the POME. The highest dry cell weight of 2.44 g/L with cell yield 0.39 (mg/cell/mg COD) was achieved at the end of experiment. A total 24.7% of TP reduction in settled POME was achieved in 144-h culture, but while a maximum 10% of TP in bacterial cell was achieved in 48-h culture. This study shows that PNSB Rhodobacter sphaeroides strain UMSFW1 grows well by using settled POME as substrate and is capable to remove TN in the settled POME and assimilate into bacterial biomass. This study could provide us a further insight in the nutrient removal and COD removal in the bioremediation process by bacterium Rhodobacter sphaeroides strain UMSFW1.
文摘A chromate-removing strain was isolated from spent chrome effluent and identified as Bacillus circulans strain MN1. The isolated strain was studied for resistance to Cr (VI) and its ability to remove Cr (VI). The strain was found to tolerate Cr (VI) concentration as high as 4500 mg/L, but the cells growth was heavily influenced when initial Cr (VI) concentration was increased between 1110 mg/L and 4500 mg/L while Cr(VI) at 500 mg/L to 1110 mg/L did not suppressed the cells growth. The experiments also demonstrated that the cells removed toxic Cr (VI) more efficiently at 30?C compared with that at 25?C and 35?C. The optimum initial pH for Cr (VI) removal was 5.6 and final pH values of 5.1-5.6 were observed for initial pH 5.2-5.7.
文摘This work is aimed at giving emphasis on the present pollution scenario in Bangladesh due to textile effluent and the consequent solution of the problem by installation of effluent treatment plant. Though the medium and small-scale industrial activities have a positive impact on the economy of our country, the increasing industrialization is contributing severe pollution to the environment by the toxic waste discharge. The liquid effluents from industries are causing a major havoc to the environment, ecology, agriculture, aquaculture and public health since the development of textile industries in the country. So, it is time to give a pause to the pollution and phase it out gradually to protect the river system. It had become a prerequisite to set up ETP in each industrial establishment, particularly at dyeing industries that were discharging huge amount of liquid waste to the rivers every day. Since the highest number of factories is of textile category and these types of factories play a major role in polluting the nature, Government’s main focus is on the textile mills and industries related to textile. But, for the successful implementation of ETPs, industry owners will have to be socially responsible and at the same time, government should provide the factory owners with logistic supports and relaxed timeframe to set up ETPs.
文摘Dyes mostly used in the textile industry end up in their wastewater. The treatment of textile effluent has become necessary because of its associated environmental and health problems. In this study, five bacterial isolates were obtained from textile effluent. The isolated bacteria were used to decolourise effluent samples in a time-dependent manner and the change in colour was observed using an Ultraviolet-visible spectrophotometer. After 24 hours, decolourisation efficiencies of the five isolates were calculated and the highest decolourisation efficiency (78.5%) was observed with one of the isolates (E12). Isolate E23 recorded 64.7% followed by isolate E9 (62.0%) and E21 (53.7%). Isolate E19 had the lowest decolourisation efficiency (2.6%). The isolated bacteria were identified with E9 as <i>Aeromonas hydrophilia</i>, E12 as <i>Aeromonas hydrophilia</i>, E19 as <i>Pseudomonas aeruginosa</i>, E21 as <i>Aeromonas hydrophilia</i> and E23 as <i>Pseudomonas fluorescens</i>. To achieve a decolourisation efficiency of 78.5%, 25 ml of textile wastewater should be inoculated with 1 ml of the isolate (E12) culture. Thus, Isolate E12 (<i>Aeromonas hydrophilia</i>) is considered a promising candidate for biological textile wastewater treatment followed by isolate E23 (<i>Pseudomonas fluorescens</i>).