F.M. Muvea; G.M. Ogendi; S.O. Omondi
Abstract
The use of constructed wetlands for purifying pre-treated wastewater is a cost effective technology that has been found to be more appropriate for many developing countries. The technology is also environmentally friendly with the wetlands being habitats for many water birds and other aquatic organisms. ...
Read More
The use of constructed wetlands for purifying pre-treated wastewater is a cost effective technology that has been found to be more appropriate for many developing countries. The technology is also environmentally friendly with the wetlands being habitats for many water birds and other aquatic organisms. This study assessed nutrient removal efficiency of two floating macrophytes (Lemna minor and Azolla pinnata). The data generated was analyzed using both descriptive and inferential statistics. The significance level was maintained at 0.05. The results showed that the wastewater physicochemical parameters did not vary during the study period. The concentrations of nitrites and nitrates increased over the experimental period in all the treatments (Azolla pinnata, Lemna minor and control), and the increase between the sampling occasions was statistically significant for the two nutrients (Nitrates: F=24.78, P= 0.00; Nitrates: F=198.26, P= 0.00). To the contrary, in all the treatments the concentrations of ammonia, total phosphorous, soluble reactive phosphorous and total nitrogen, decreased over the experimental period. The decrease in concentration for these nutrients between the sampling occasions was statistically significant (ammonia: F=195.57, p= 0.00; total phosphorous: F= 56.50, p= 0.00; soluble reactive phosphorous: F= 37.11, p= 0.00; total phosphorous: F= 104.025, p= 0.00). Azolla pinnata proved to be better than Lemna minor in the uptake of the nutrients particularly for the soluble reactive phosphorous (F= 35.18, P= 0.044). We conclude that the two macrophytes are good for wastewater treatment. It is recommended introduction and/or multiplication of Azolla pinnata in the constructed wetlands meant for wastewater treatment especially within the tropics.
J. Samaniego; M.A.N. Tanchuling
Abstract
The use of amalgamation process to recover gold from mined ores by the small-scale gold miners in the Philippines and other developing countries produces and dispose of untreated wastewater to the receiving water bodies. In this study, a field-scale filter bed system was constructed to treat heavy metal ...
Read More
The use of amalgamation process to recover gold from mined ores by the small-scale gold miners in the Philippines and other developing countries produces and dispose of untreated wastewater to the receiving water bodies. In this study, a field-scale filter bed system was constructed to treat heavy metal metal-laden wastewater collected from small-scale gold mining site in Paracale, Camarines Norte, Philippines. The filter bed system was consists of sedimentation tank and filter bed with Cocopeat, a by-product of coconut husk, as adsorbent. Physico-chemical parameters (temperature, pH, oxidation-reduction potential, electrical conductivity, turbidity, dissolved oxygen, total dissolved solids, salinity, total suspended solids, color) and heavy metal (As, Ba, Cd, Hg, Pb) concentrations were monitored during the 50 days experiment at a flow rate of 40 Liter per hour for 3 hours daily wastewater application. Significant reduction was achieved on heavy metals; As (97.11%), Ba (39.75%), Cd (74.24%), Hg (97.02%), Pb (98.82%) from small-scale gold mining (SSGM)wastewater in sedimentation phase and further reductions on As (1.39%), Ba (28.00%), Cd (4.95%), Hg (2.91%), Pb (0.97%) were achieved by adsorption in the Cocopeat filter bed. Measured effluent physico-chemical parameters and heavy metal concentrations were within the respective regulatory limits. Other effluent parameters with strong correlation with total suspended solids such as turbidity and color, though not regulated, were reduced significantly. All adsorbed heavy metals accumulated in the upper 25 cm of the Cocopeat column in the filter bed. Measured heavy metal concentrations in Cocopeat suggest that the adsorbent was not saturated and further application of small-scale gold mining wastewater is recommended to determine its useful life.
A. Cruz-Salomón; E. Ríos-Valdovinos; F. Pola-Albores; S. Lagunas-Rivera; R. Meza-Gordillo; V.M. Ruíz-Valdiviezo; K.C. Cruz-Salomón
Abstract
The expanded granular sludge bed bioreactor appears today as a cheap, robust and more popular technology because it operates using a fluidized bed, which allows increasing in organic load and in cell retention times, generating higher treatment efficiencies (up to 95 %) and renewable energy (i.e., biogas, ...
Read More
The expanded granular sludge bed bioreactor appears today as a cheap, robust and more popular technology because it operates using a fluidized bed, which allows increasing in organic load and in cell retention times, generating higher treatment efficiencies (up to 95 %) and renewable energy (i.e., biogas, biomethane, and biohydrogen). Nevertheless, the efficiency of this bioreactor mainly depends on the operating conditions. Thus, the content presented in this review paper focuses on the analysis of the operating conditions and performance of expanded granular sludge bed bioreactor for treating different types of industrial, agro-industrial and domestic wastewaters (e.g., agro-food, beverage, alcohol distillery, tannery, slaughterhouse, chemical, pharmaceutical, municipal sewage, among others). Because of this reason, this study aimed to analyze the operating conditions and type of substrate, which has been used in these bioreactors to improve future research to wastewater treatment and renewable energy production. According to the review, it is concluded that the EGSB bioreactor is a novel sustainable alternative to treat different types of wastewaters and consequently change the paradigm of wastewater management from "treatment and disposal" to "beneficial use" as well as "profitable effort".
D. Sivakumar; J. Nouri; T.M. Modhini; K. Deepalakshmi
Abstract
Water is prime requirement for surviving of any living beings. The existence of surface water and groundwater sources are used for domestic, agriculture and industrial purposes in all over the world. Fresh water from both the water sources is highly contaminated in recent years because of rapid ...
Read More
Water is prime requirement for surviving of any living beings. The existence of surface water and groundwater sources are used for domestic, agriculture and industrial purposes in all over the world. Fresh water from both the water sources is highly contaminated in recent years because of rapid population growth, modern agriculture and industrial growth. Among them, contamination of water sources due to industrialization is high and it requires more attention to protect those water sources. In this study, nickel removal from electroplating industry wastewater was done with the help of bamboo activated carbon. The nickel removal from electroplating industry wastewater by bamboo activated carbon was done in this study at various adsorbent dosages (0.5, 1.0, 1.5 and 2.0 g/L), agitation speeds (25, 50, 75 and 100 rpm), particle sizes (2.36, 1.18, 0.6 and 0.3 mm), and concentration dilutions (0, 25, 50, 75 and 100%). The maximum removal percentage of nickel from electroplating industry wastewater using bamboo activated carbon was found to be 98.7 % at an optimum adsorption dosage 1.5 g/L, agitation speed 25 rpm, particle size 0.6 mm and concentration dilution 75 % with 110 min. contact time and 5.5 pH. Functional groups available in a bamboo activated carbon before and after treatment were determined by fourier-transform infrared spectroscopy analysis. Fourier-transform infrared spectroscopy analysis specified that alkanes, carboxylic acids, esters, amides, amines, aromatic compounds, alkyl halides, ethers, alcohols, carboxylic acids, aldehydes functional groups in bamboo activated carbon was contributed for removing nickel from the electroplating industry wastewater. Isotherm models were used to know the adsorption behaviour of bamboo activated carbon for removing nickel from electroplating industry wastewater. Isotherm results revealed that Langmuir model was best suited with the equilibrium data than Freundlich model. Finally, this study concluded that bamboo activated carbon was best suited for removing nickel from electroplating industry wastewater.
M. Keshvardoostchokami; L. Babaei; A.A. Zamani; A.H. Parizanganeh; F. Piri
Abstract
In this study, an easy synthesized method for preparation of chitosan/iron oxide nanocomposite as a bio-sorbent has been applied. Analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction; Field emission scanning electron microscopy and transmission electron microscopy ...
Read More
In this study, an easy synthesized method for preparation of chitosan/iron oxide nanocomposite as a bio-sorbent has been applied. Analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction; Field emission scanning electron microscopy and transmission electron microscopy were utilized to survey of morphological structure and the functional groups characterization. The histogram of frequency of particle size confirmed that medium size of the synthesized nanoparticles was 50 nm. Beside the obtained nanocomposite, application of chitosan as the precursor and shrimp shell as natural chitin and a natural polymer were assessed as adsorbents for decontamination of Ni2+, Cd2+ and Pb2+ as examples of heavy metals from drinking water. Batch studies were performed for adsorption experiments by changing variables such as pH, contact time and adsorbent dose. Based on the experimental sorption capacities, 58, 202 and 12 mg of Ni, Cd and Pb per g of Chitosan-Fe2O3 nanocomposite as adsorbent respectively, confirm that combination of Fe2O3 nanoparticles with chitosan makes a more efficient adsorbent than chitosan and chitin. Adsorbents in uptake of the mentioned heavy metals are in the order of Chitosan-Fe2O3 nanocomposite > chitosan> chitin. In addition, the kinetics and isotherm investigations were surveyed. Moreover, it has been shown that the synthesized nanocomposite significantly reduces the amount of the mentioned ions from the real wastewater sample.
