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Pulp and Paper Mill Effluent Treated by Combining Coagulation-Flocculation-Sedimentation and Fenton Processes
2018
Grötzner, Mariana | Melchiors, Emeline | Schroeder, Luiz Henrique | dos Santos, Alexandre Renato | Moscon, Kethlyn Ghellere | de Andrade, Marco Antonio | Martinelli, Sérgio Henrique Saavedra | Xavier, Claudia Regina
Pulp and paper industries face serious environmental challenges, especially with regard to the conservation of water resources. Chemical thermal mechanical pulping (CTMP) is a process of pulping that combines chemical and mechanical pulping. This reduces the volume of water used in the process. But on the other hand, CTMP generates an effluent with high concentration of organic matter and is difficult to treat. This study evaluated the efficiency in the combination of physicochemical pretreatment by coagulation-flocculation-sedimentation (CFS) process and advanced oxidation process (AOP) by Fenton in sequence to treat CTMP effluent of a Brazilian industry. At first, the best treatment conditions for this type of effluent were determined. To evaluate the efficiency, pH, chemical oxygen demand, biochemical oxygen demand, total organic carbon, lignin contents, color, total phenolic contents, turbidity, and solids were measured before and after treatment. The acute toxicity on Daphnia magna was also determined. The treatment with CFS showed better results in the removal of solids and Fenton in the removal of recalcitrant compounds, such as lignin, demonstrating the need to use them in sequence. Combining CFS and Fenton to treat CTMP effluent allowed to achieve a removal efficiency of 95% for TOC, 61% for COD, and 76% for lignin contents.
Show more [+] Less [-]Dynamics of Clay Particles in Non-vegetated Stormwater Biofilters
2018
Subramaniam, Daniel N. | Logeswaran, T. | Tharshikka, V. | Nilakshan, B.
Stormwater biofilters manage quantity and quality of urban stormwater runoff. Particulate solids from natural and anthropogenic sources accumulate on paved surfaces and eventually reach receiving waters. Retention of suspended solids in stormwater management systems ensures the quality of stormwater runoff to water resources. Stormwater biofilters are similar in most of design parameters to sand filters employed in water treatment systems. The understanding and design of stormwater biofilters are often based on generic models of sand filters. Unlike water treatment sand filters, which are continuously fed, stormwater biofilters operate intermittently with spontaneously alternating wetting and drying cycles. This results in dynamic pollutant removal pattern that employs different mechanisms during and across rainfall events. As such, pilot scale biofilter columns fabricated with a layer of organic material were operated. Removal of suspended solids was very dynamic, where impact of age of filter, antecedent dry days, and inflow quality varied during and across events. Flush of retained solids and filter material occurred during the stabilisation period during each event while very high removal percentages (more than 90%) were observed after stabilisation, during an event. Clogging was not observed due to re-entrainment, re-distribution, and flush of retained solids during intermittent wetting and drying cycles.
Show more [+] Less [-]Effect of salinity stress on phenotypic plasticity, yield stability, and signature of stable isotopes of carbon and nitrogen in safflower
2018
Hussain, Muhammad Iftikhar | Al-Dakheel, Abdullah J.
Salinity is one of the major factors contributing in land degradation, disturbance of soil biology, a structure that leads to unproductive land with low crop yield potential especially in arid and semiarid regions of the world. Appropriate crops with sufficient stress tolerance capacity and non-conventional water resources should have to be managed in a sustainable way to bring these marginal lands under cultivation for future food security. The goal of the present study was to evaluate salinity tolerant potential (0, 7, and 14 dS m⁻¹) of six safflower genotypes that can be adapted to the hyper arid climate of UAE and its marginal soil. Several agro-morphological and physiological traits such as plant dry biomass (PDM), number of branches (BN), number of capitula (CN), seed yield (SY), stable isotope composition of nitrogen (δ¹⁵N) and carbon (δ¹³C), intercellular CO₂ concentration from inside to ambient air (Ci/Ca), intrinsic water use efficiency (iWUE), carbon (C%) and nitrogen (N %), and harvest index (HI) were evaluated as indicative of the functional performance of safflower genotypes under salt stress. Results indicated that salinity significantly affected the seed yield at all levels and varied significantly among genotypes. The BN, PDM, CN, and δ¹³C attributes showed clear differentiation between tolerant and susceptible genotypes. The δ¹³C results indicate that the tolerant genotypes suffer less from stress, may be due to better rooting. Tolerant genotypes showed lower iWUE values but possess higher yield. Safflower genotypes (PI248836 and PI167390) proved to be salt tolerant, stable, and higher seed and biomass yielder. There was no G × E interaction but the genotypes that produce higher yield under control were still best even under salt stress conditions. Although salinity reduced crop yield, some tolerant genotypes demonstrate adaptation and good yield potential under saline marginal environment.
Show more [+] Less [-]Bioremediation of Phenol-Contaminated Industrial Wastewater Using a Bacterial Consortium—from Laboratory to Field
2017
Poi, Gregory | Aburto-Medina, Arturo | Mok, Puah Chum | Ball, A. S. | Shahsavari, Esmaeil
Singapore is an island city state with an economy dependent on petrochemicals and shipping, but with severely limited water resources. This study aimed to establish a suitable methodology specifically for the translation of a laboratory-scale system to an industrial scale for the treatment of phenol-contaminated wastewater. A habitat-specific microbial consortium was developed and reconstituted from 22 pure cultures dominated by Acinetobacter sp., Bacillus sp. and Pseudomonas sp. to form a synthetic biofilm-forming community with the capacity to degrade phenol-contaminated wastewater. The laboratory experiment was scaled-up to 400 m³ by using biotrickling reactors to reduce the phenol level from 407 mg L⁻¹ to below detection limit over 104 days incubation. The results showed that the microbial consortia could also reduce the toxicity of the wastewater while degrading the phenol and lowering the wastewater COD. Further, this approach could be translated into the field without the need for a purpose-built primary treatment facility preventing the generation of excessive biomass and eliminating the need for sludge disposal.
Show more [+] Less [-]Clustering of the Districts of West Bengal Based on Spatial and Temporal Distribution of Groundwater Table Depth Towards Effective Monitoring and Management of the Valuable Water Resources
2015
Vishwajith K. P. | Sahu P. K. | Noman Md. | Dhekale B. S. | Narasimhaiah L.
Fluctuations of groundwater table (GWT) has great role in agriculture through assured supply of irrigation in industry and other fronts. As such, probability of possible GWT also plays an important role in terms of efficient usages of this valuable resource. An attempt has been made to find probability distributions taking seasonal (January, May, August and November for 2005 to 2013) information on GWT for the districts under five agro-climatic zones of West Bengal. The study reveals that 17 districts of West Bengal, India, can be categorised into 6 probability model groups: Weibul, Normal, Weibul (3P), Log Logistic (3P), Log Normal (3P) and Gamma (3P). These models can be used to ascertain the probability of occurrences of GWT in specific district. Cluster analysis, using GWT figures for various seasons over the period of study reveals that the districts could be grouped into four clusters, which in-turn may facilitate clusterwise strategy for restricting the depletion of GWT depth or maintenance of the same. These techniques can be used for intradistrict GWT analysis for efficient monitoring of GWT.
Show more [+] Less [-]Kinetic Study of BTEX Removal Using Granulated Surfactant-Modified Natural Zeolites Nanoparticles
2011
Seifi, Laleh | Torabian, Ali | Kazemian, Hossein | Bidhendi, Golamreza Nabi | Azimi, Ali Akbar | Farhadi, Farshid | Nazmara, Shahrokh
Increasing release of organic pollutants to the environment has caused one of the largest world crises for water resources. Volatile organic compounds are toxic monoaromatic pollutants of soil and water. In this research, natural zeolite nanoparticles were produced mechanically by means of a milling technique, modified using two cationic surfactants of hexadecyltrimethylammonium chloride and n-cetyl pyridinium bromide and formed as granules using a novel technique already developed by our group. The granulated adsorbents were used to uptake benzene, toluene, ethylbenzene, and xylenes (BTEX) from contaminated water. Two intra-particle diffusion models (i.e., Weber and Morris and Vermeulen models) and three surface reaction models (i.e., pseudo-first order, pseudo-second order, and Elovich) were applied to evaluate the kinetics of adsorption and the best fitted model was chosen. Results of the adsorption kinetic evaluations were shown that uptake of granulated nanozeolites are higher than natural zeolites (in the order of four). Kinetic results revealed that the adsorption follows a pseudo-second order indicating existence of chemisorption in the studied conditions. It was noticed that the intra-particle diffusion is prevailing in the first stage of adsorption for a relatively short time (i.e., first 25Â min).
Show more [+] Less [-]Consumers’ knowledge, attitude and behavioural patterns towards the liquid wastes (cooking oil) in Istanbul, Turkey
2019
Gurbuz, Ismail Bulent | Ozkan, Gulay
This study was carried out to reveal the people’s knowledge level about the harmful effects of waste oils, especially waste cooking oil, on the environment. It also aims to understand the attitude and behavioural patterns related to the safe disposal of them. Istanbul is chosen because it represents the entire country with its diverse socio-demographic and socio-cultural structure. A total of 408 respondents were randomly chosen and interviewed in the designated regions. The research data were obtained by using a structured survey consisting demographic and Likert scale questions. SPSS 23.0 statistical software was used to analyse the survey data. Results suggest that despite the high educational level, participants did not know that household liquid waste has a negative impact on the environment. They disagreed on the statement that liquid waste can damage water resources. Public spots, and formal and informal education were not found effective and failed to make the desired impact. Majority of participants did not know their duties in the disposal of waste. They also did not know where the liquid waste collection units were and what projects were being implemented in their neighbourhood. Fewer participants were concerned at what point and how the hazardous liquid wastes collected by municipalities were disposed of after leaving their habitat and whether these methods were reliable or acceptable. This research concludes that user behaviour was disappointing in cooking oil usage and waste oil disposal. The collection of waste cooking oils remains far below the developed countries.
Show more [+] Less [-]Toxicological Effects of Surface Water Exposed to Coal Contamination on the Test System Allium cepa
2018
Artico, Leonardo Luís | Kommling, Gizele | Migita, Natacha Azussa | Menezes, Ana Paula Simões
Process related to power generation, i.e., extraction and burning of coal, strongly affects the soil, water resources, and air quality. Pollutants generated by the coal mining can lead to a number of environmental problems and has become matter of global concern. This study has focused on to evaluate the cytotoxicity and phytotoxicity of surface waters collected in the surroundings of the Thermoelectric Power Plant President Médici-UTPM (Candiota, Brazil), through Allium cepa bioassay and physicochemical analyzes. Three water samples collected at points P1, P2, and P3 were compared to the negative control (NC) for all variables analyzed. The P2 sample resulted in the lowest mitotic index (MI) values (23, 33.1, and 40.7%), followed by P1 (23, 33.1, and 40.7%). However, the P3 sample had the highest MI values (50.2, 40.1, and 36.3%) and was the most mutagenic sample compared to NC and other treatments. Samples P1, P2, and P3 were phytotoxic to A. cepa, resulting in abnormal seedlings. Through physicochemical analysis, all collected water samples showed high electrical conductivity and turbidity, indicating an increase in the deposition of metallic ions and organic compounds in these samples. Based on these findings, we can conclude that the analysis of surface water is an important step for screening mining areas potentially contaminated by coal compounds. Therefore, our study points out some consequences of mining process, in terms of A. cepa bioassay as well as their harmful effect on physicochemical constituents of surface waters, indicating the need for environmental monitoring of this region.
Show more [+] Less [-]Effects of Salinity on Herbicide Lactofen Residues in Soil
2018
Jing, Xu | Yang, Jiali | Wang, Tengfei
Soil salinization is an increasing problem in agricultural soils on a worldwide scale. To assess the effects of salinity on the fate of herbicide lactofen in soil, laboratory degradation experiments were performed using soil with and without additional salinity. Lactofen and two major metabolites desethyl lactofen and acifluorfen were analyzed using HPLC-MS/MS. The degradation of lactofen and metabolites followed first-order kinetics with rate constants ranged from 0.30 to 0.35 day⁻¹ (estimated half-lives from 1.99 to 2.30 days) when additional salinity was not present. Lactofen concentration was greater in the salinized soil than in the control soil. The maximum concentrations of metabolites desethyl lactofen and acifluorfen were increased by 6.9 and 53% in salinized soil compared to control soil, respectively. The degradation of lactofen and metabolites was restrained by the application of salts and residues remained for a longer time in the salinized soil. Inappropriate management of soil and water resources may lead to the increase of salinity, which has the potential to enhance pesticides residues risk in soil.
Show more [+] Less [-]The effects of groundwater depth on water uptake of Populus euphratica and Tamarix ramosissima in the hyperarid region of Northwestern China
2016
Chen, Yapeng | Chen, Yaning | Xu, Changchun | Li, Weihong
Knowledge of the water sources used by desert trees and shrubs is critical for understanding how they function and respond to groundwater decline and predicting the influence of water table changes on riparian plants. In this paper, we test whether increased depth to groundwater changed the water uptake pattern of desert riparian species and whether competition for water resources between trees and shrubs became more intense with a groundwater depth gradient. The water sources used by plants were calculated using the IsoSource model, and the results suggested differences in water uptake patterns with varying groundwater depths. At the river bank (groundwater depth = 1.8 m), Populus euphratica and Tamarix ramosissima both used a mixture of river water, groundwater, and deeper soil water (>75 cm). When groundwater depth was 3.8 m, trees and shrubs both depended predominantly on soil water stored at 150–375 cm depth. When the groundwater depth was 7.2 m, plant species switched to predominantly use both groundwater and deeper soil water (>375 cm). However, differences in water acquisition patterns between species were not found. The proportional similarity index (PSI) of proportional contribution to water uptake of different water resources between P. euphratica and T. ramosissima was calculated, and results showed that there was intense water resource competition between P. euphratica and T. ramosissima when grown at shallow groundwater depth (not more than 3.8 m), and the competition weakened when the groundwater depth increased to 7.2 m.
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