Volumen 3, Asunto 5 (2012)

Artículo de investigación

Adsorption of Methylene Blue from Aqueous Solutions using Fe3O4/ Bentonite Nanocomposite

Hashem FS

Magnetic Fe3O4/bentonite nanocomposite was prepared by chemical co-precipitation method. The product was characterized by X-ray diffraction and Scanning electron microscope. Batch adsorption experiments were carried out for the removal of methylene blue from aqueous solutions using Fe3O4/bentonite nanocomposite. Effects of pH of the initial dye solution, mass of the adsorbent and the contact time on the adsorption capacity were studied. The results showed that the adsorption capacity for the dye increased by increasing the contact time and initial pH of the solution. However, it decreased with increasing the mass of the adsorbent. The adsorption behaviors of the nanocomposite showed that the adsorption kinetics and isotherms were in good agreement with pseudo 2nd order kinetic equation and L angmuir equation, respectively, and the maximum adsorption capacity was 1600 mg/g. For this the prepared nanocomposite could be regarded as a potential adsorbent for MB removal in a wastewater treatment.
Artículo de investigación

Optimal Well Design for Enhanced Stimulation Fluids Recovery and Flowback Treatment in the Marcellus Shale Gas Development Using Integrated Technologies

Richard Olawoyin, Christian Madu and Khaled Enab

A typical well was designed with formation properties in Springfield Township, Bradford County, Pennsylvania using computer modeling group (CMG) software to analyze the production potential in the area over 40 years. Multilateral wells gave the highest initial gas production rate and cumulative production of 1.18E+07 ft3/day and 2.6E+10 ft3 respectively. FracPro® software was used for the fracture design. The simulation demonstrates that hydraulic fracturing can appreciably increase cumulative production and production rate in the well, with an estimated 3.6 Million gallons (of water) per well required to fracture open the formation for the free flow of gas. Due to the efficient well design and stimulation design, a load recovery of approximately 86% of the injected fluid is achievable which amount to 73,714 bbls of waste water to be treated per stimulation job. The system capacity of the forward osmosis integrated process, operating on hydraulic fracturing flow-back water will treat 604,800 gallons per day (gal/d). The novel design takes into consideration the flow-back recovery per hour in the system, which is 600 bbl/ hr for the centralized system, but 150 bbl/hr for a single well pad. The tank size required would be a 25,000 gallon tank, covering approximately 1,202 square feet and cost $52,255. The forward osmosis (FO) system uses a thin-film composite (TFC) membrane system based on efficiency and power generation capabilities. The capital cost of each system is about $100,000. The annual operating cost of the FO system would be about $ 0.60/kgal of produced water. A cost estimate savings of over one million dollars ($1,000,000) is expected if the integrated forward osmosis system is implemented. Aside cost savings, the emission generated from the system is minimal, which makes it considerably environmentally friendly compared to other types of treatments.

Artículo de revisión

Innovative Application of Scientific Fact for Nutrient Recovery from Waste Water Streams for Sustainable Agriculture and Protection of Environment: A Review

Yadav RC

Organic manure is an essential component of nutrient management for sustainable agriculture, where in use of slurry extracted from the waste water streams becomes a reliable, accessible and cheap source of such nutrient rich materials. This study presents a scientific fact of sulphur cycle that governs aerobic and anaerobic decomposition of wastes which have adverse impact on environment. Working of scientific fact is substantiated in the study. Review was carried out on use of the scientific fact in the existing practices for nutrient and water use and capitalizing the waste materials. It is found that although benefits are realized, the working of scientific fact of sulphur cycle is not visualized. Relevant application of the scientific fact of sulphur cycle viz. aerobic decomposition works well in practice of NADEP composting prevalent in India. Further, usage of the innovation of aerobically decomposed green manuring will serve as an engine for driving the recovery of nutrients from waste streams. The innovative products so far developed still have some limitations of use. Several manifestations of the scientific fact are presented that are in practice and some in perspective to bring sustainable agriculture. It warrants conducting studies on optimization under generation II (2G) of factors those found promising under generation I (1G). Some prominent research areas are also chalked out whose results when implemented will bring sustainable agriculture and promote clean and green environment conservation.

Artículo de investigación

Restoration versus Re-flooding: Mesopotamia Marshlands

Ali Abdul Zahra Douabul, Nadia A. Al-Mudhafer Abdulzahra A. Alhello1, Hamid Talib Al-Saad and Sama Sameer Al-Maarofi

The current water physiological and chemical parameters in the re-flooded marshes of the Mesopotamia are investigated from March 2005 to August 2008. Generally, desiccation, among the several natural and anthropogenic activities (water shortage, dams’ constructions), had the worst damage sequences that led to destroy the Mesopotamian’s ecosystem. Understanding the current physicochemical structure of the re-flooded marshes are important in order to evaluate the ecological function of the newly wetlands. This study will assess the ecological function of some of the re-flooded marshes based on their historical status in the 1970’s. The assessment will observe the overtime changes of water quality parameters, nutrients and major ions concentrations of the Mesopotamian marshlands before and after desiccation in thirty re-flooded marshes. During the study period, and under the stagy hydrological situation of Iraq, the average salinity concentration of the marshes was increased from 0.5 ppm to 1.6 ppm. The pH values were mostly in the basic range which is similar to previous studies. High range of dissolved oxygen concentrations were recorded that mostly related to the seasonal differences and photosynthesis. The significant differences between the major ions concentrations among the three marshlands indicate the differences in the water resources of each marshland, which mainly related to the tidal effect of Arabian Gulf via Shatt Al-Arab River. The early monitoring of PO4, NO2, NO3, and SiO2 concentrations were high and then their concentrations started to decline overtime, which is good indicator that the marshlands are naturally are recycle and remove the extra concentrations of nutrients and avoid nitrification. Also the principal component analysis indicates that the historical conditions of the marshlands were changed dramatically overtime even before the desiccation period.

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