Heavy Organic Load Research Articles

Investigation of graphene oxide as highly selective adsorbent in recovery of hydroxytyrosol from olive mill wastewater

Olive mill wastewater (OMW) is produced in large quantities in the production of olive oil with the three-phase method. This waste, which is not biodegradable and characterized by a heavy organic load containing toxic components (such as phenols), is usually given to aqueous receptors or soil, either directly (untreated) or treated inadequately. Biologically active phenolic compounds that inhibit biodegradation of this waste are toxic at high concentrations, especially for microorganisms, but have positive effects with strong antioxidant properties on human health when properly isolated and properly concentrated. Hydroxytyrosol (HT) is one of the most interesting and abundant compounds among the biophenols present in OMW. According to this study, a newly synthesized nanomaterial, graphene oxide (GO), has been utilized for the separation of HT and total biophenolic substance from OMW. Graphene oxide from graphite oxidation was synthesized using a modified Hummer’s method. In order to understand how GO behaves during thermal degradation, thermogravimetric/differential scanning calorimetry analyses were performed. Two-parameter and three-parameter equilibrium isotherm models and kinetic models have been used to determine the mechanism of kinetic sorption and adsorption type. Thermodynamic data indicate that the adsorption process is exothermic, applicable and spontaneous.

A comparative study on the treatment of gelatin production plant wastewater using electrocoagulation and chemical coagulation

Effluents from gelatin production plants are highly complex and difficult to treat by conventional methods. The Electrocoagulation (EC) technique was evaluated to treat effluents that contain a heavy load of Chemical Oxygen Demand (COD) and a large quantity of suspended solids. This paper presents results of laboratory scale studies that compare the performance of Chemical Coagulation (CC) with aluminum salts and EC with aluminum electrodes. The heavy organic load and suspended solids in this kind of wastewater lead to low performance in the secondary treatment. SEM-EDS were used to analyze the sludge formed in the EC process and the removal mechanism of pollutants from the wastewater. The structure and composition of the precipitates at different operation conditions, such as pH, show that EC has increased efficiency of COD removal, compared to CC with the same dose of aluminum (Al+3) as coagulant. The efficiency of COD removal was 73.6% with EC and 55.6% with CC. The in-situ formation of zeolites in the EC process explains the high efficiency of this treatment compared to the CC process. The zeolite formation during the EC process in the wastewater of the gelatin production plant has not been reported until now.

Variations in the reproductive cycle of the oyster crassostrea virginica (gmelin, 1791), pueblo viejo lagoon, veracruz, mexico

1 - Mexican oyster production in the Gulf of Mexico has fallen drastically in most coastal lagoons, whereas Pueblo Viejo Lagoon production (state of Veracruz) has been sustained, providing a source of seed for the restocking of other lagoons. This has been achieved due to bed management carried out by local fishermen. This management is based on empirical knowledge of seed collection from planted shell beds. 2 - This study describes variations in gametogenic activity and the reproductive cycle during the year 2002, with a view to improving shell laying programs. Samples were taken from two beds, subject to different environmental and pollution conditions. Malagana point, with a heavy organic load and a strong tidal current, and Matacuaya Island, with a low organic load and no current. 3 - Thirty oysters over 8 cm shell length were sampled monthly from each bed for histological analysis of the gonad tissue. 4 - There were variations in gonad activity between localities, which are reflected in the gametogenic cycle and spawning. At both stations spawning extends throughout the year, but in larger numbers from June to October at Malagana, contrasting with a low frequency for most of the year and one intense spawn during July and August at Matacuaya. 5 - These differences in the gametogenic cycles and spawning periods are a result of population recovery capacities under different environmental conditions. The Malagana population is exposed to a higher organic load from the Panuco River in addition to urban discharge, resulting in shorter post-spawn and rest periods, faster gametogenesis, and a well defined mature stage with a high intensity spawning period and three peaks. Meanwhile, the oyster population from Matacuaya presented longer, more intense post-spawn and rest stages; gametogenesis extended longer, in a lower percentage of the population, with a brief maturity period. 6 - This differential reproductive behaviour has positive implications in recruitment, giving the oyster populations from Pueblo Viejo lagoon the opportunity to take advantage of every settlement possibility throughout the year. However, the higher organic load that enhances reproduction at Malagana poses a health risk, given the high fecal bacteria count and heavy metal concentration in the sediment, constantly re-suspended by the tidal current flux.

Efficacy of Sanitizers To Inactivate Escherichia coli O157:H7 on Fresh-Cut Carrot Shreds under Simulated Process Water Conditions

Chlorine is widely used as a sanitizer to maintain the microbial quality and safety of fresh-cut produce; however, chlorine treatment lacks efficacy on pathogen reduction, especially when the fresh-cut processing water contains heavy organic loads. A more efficacious sanitizer that can tolerate the commercial processing conditions is needed to maintain microbial safety of fresh-cut produce. This study evaluated the efficacy of Escherichia coli O157:H7 reduction on fresh-cut carrots using new and traditional sanitizers with tap water and fresh-cut processing water scenarios. Fresh-cut carrot shreds inoculated with E. coli O157:H7 were washed in sanitizer solutions including 200 ppm chlorine, citric acid–based sanitizer (Pro-San), 80 ppm peroxyacetic acid-based sanitizer (Tsunami 100), and 1,000 ppm acidified sodium chlorite (SANOVA) prepared in fresh tap water or simulated processing water with a chemical oxygen demand level of approximately 3,500 mg/liter. Samples were packaged and stored at 5°C. Microbial analyses performed at days 0, 7, and 14 indicate that the organic load in the process water significantly affected the efficacy of chlorine on pathogen removal and was especially evident on samples tested during storage. Acidified sodium chlorite provided a strong pathogen reduction even under process water conditions with up to a 5.25-log reduction when compared with the no-wash control. E. coli O157:H7 was not recovered on acidified sodium chlorite–treated samples during the entire 14 days of storage, even following an enrichment step. These results suggest that acidified sodium chlorite holds considerable promise as an alternative sanitizer of fresh-cut produce.

Exponential Collapse of Benthic Depurative Capacity in A Eutrophic Tropical Marine Ecosystem: A Threshold Response to Organic Nitrogen Loading

Microbial decomposition of particulate organic matter in sediments can substantially modulate eutrophication of nearshore marine environments. Flux budgets for nitrogen compounds and quantification of rates of microbial transformation can provide important information on the process of eutrophication. This survey documents sediment nitrogen budgets for a eutrophic nearshore marine environment at La Parguera on southwest coast of Puerto Rico, including consideration of the organic fraction in addition to microbial transformations. Sediments of the inshore channel at La Parguera denote the input of heavy organic loads with low redox potentials and high ammonium contents. Benthic fluxes of dissolved organic nitrogen are below those recorded for ammonium. These observations suggest that nearshore tropical sediments subject to heavy nitrogen loads act as a sink for organic nitrogen and that ammonification is a key process in the release of nitrogen from sediments to the water column. Nitrification and denitrification rates are low overall and inversely related to the redox potential. Depuration of excess nitrogen through denitrification is ineffective in these sediments. in contrast to more robust temperate environments, our work demonstrates that tropical marine systems are particularly susceptible to eutrophication given their limited capacity for depuration of excess nitrogen.

River‐Groundwater Exchanges, Bank Filtration, and Groundwater Quality: Ammonium Behavior

AbstractIn many countries, bank‐filtrated water is an important component of the drinking water production. In this case, most of the water pumped from the alluvial aquifers originates from the adjacent river. Bank‐filtration is generally considered beneficial both quantitatively and qualitatively. However, in some cases bank filtration can cause deleterious effects to groundwater quality. This paper describes such a case, focusing on ammonium (NH4) concentrations. The data were gathered at an experimental bank‐filtration site which is part of a large well field along the Seine River (France). At this site, groundwater was sampled along a flow line path and pore water of river bed sediments was collected with peepers or by centrifuging core samples. The pore waters of the superficial river bed sediments have high ammonium concentrations (>30 mg NH4 L−1) whereas, in the groundwater, these concentrations are lower (≤20 mg NH4 L−1), with higher concentrations near the bank. The high NH4 concentration in the sediment is related to the heavy organic load in the river and the mineralization of this organic matter by benthic microflora. Among the different mechanisms that influence NH4 transport and retention in the porous medium, it emerges that sorption by the alluvial sediments (Kd = 1 − 10 × 10−3 m3 kg−1), or even the chalk (Kd = 48 × 10−3 m3 kg−1) seems to be effective in retaining NH4. This is illustrated by a model of NH4 transfer with retardation adapted to the conditions of the site. Precipitation of NH4 salts is probably not involved in regulating NH4 concentrafion at this site.

Detection ofAeromonasand microbiological indicators in fish marketed in Israel

This study was conducted to determine the microbial and enteric virus quality of fresh fish sold on the open market in Israel. Three species of fish were studied: bottom feeders carp and tilapia, which tolerate heavy organic loads, and trout growing in high quality fresh water. Samples of liver, spleen, skin and muscle were assayed for Aeromonas, E. coli and F+ coliphages; digestive tract (DT) samples were assayed also for enteric viruses. The highest concentration of microorganisms was found in carp followed by tilapia and trout. Aeromonas was highest in the DT and lowest in muscle. E. coli and F+ coliphages were not detected in trout tissue other than skin. Enteric viruses were detected only in the DT of the carp (15%), indicating the presence of wastewater of human origin in the growth ponds. The results show that the degree of contamination reflected the quality of water in which the fish were grown. Caution in handling and preparing fish is recommended to avoid cross‐contamination of other tissues by...

Impact of Mosul textile factory effluents on Tigris River water quality

Abstract Industrial wastes are frequently a source of troubles and expences at municipal sewage treatment plants. Their volumes may add to the capacity of the plants. They may impose heavy organic loads or may be of such nature that will upset the normal operation of the plants. When discharged to the watercourses, they give rise to heavy pollution from which humans, animals, plants and equatic life suffer its consequences. Industries are used to consume a huge quantities of water for their different process purposes. A considerable amount of this water may be unjustifiably wasted. This last case is evidently noticed at Mosul Textile Factory (MTF). The water used for production exceeds the amount actually needed. The characteristics of textile wastes were studied in term of BOD, S.S., hardness and other parameters. The study concluded that such wastes were generally colored, highly alkaline, high in BOD contents, high in suspended solids and hot. Effluents might contain some chemicals which might be toxic...

THE STABILITY IN WATER OF A NEW CHLORAMINE DISINFECTANT AS A FUNCTION OF pH, TEMPERATURE, AND WATER QUALITY1

ABSTRACTThe stabilities in water and dry storage of two solid‐state disinfectants (3‐chloro‐4, 4‐dimethyl‐2‐oxazolidinone, agent I, and calcium hypochlorite) have been compared under a variety of conditions. Variables in the study included pH, temperature, and water quality. Agent I is considerably more stable in dry storage and in water, especially at pH 4.5 and 7.0, than is calcium hypochlorite. This is true for solutions of the two compounds in sterile, distilled, deionized, demandfree water or in a synthetic water containing heavy organic load. Prior work in these laboratories concerning use of agent I as a disinfectant for lake water in a laboratory‐scale treatment plant had suggested that agent I has considerable potential for use as an alternative to cholorine gas for water disinfection. The present work suggests that agent I is of sufficient stability to be of use as a solid‐state disinfectant for swimming pools and for potable water for remote areas.