Wyniki wyszukiwania - Biblioteka Nauki

1

Reverse osmosis as one-step wastewater treatment: a case study on groundwater pollution

100%

Ali W. , Rehman W. U. , Younas M. , Ahmad M. I. , Gul S.

Polish Journal of Chemical Technology

|

2015

|

tom Vol. 17, nr 4

42--48

EN

The present case study is focused on performance evaluation of a Reverse Osmosis (RO) membrane based pilot plant to treat the ground/surface drinking water sources polluted by flood, rivers and/or canals. The RO plant was designed, fabricated and then operated with polluted water. Two feed water samples having a TDS of 2.000 mg · L−1 and 10.000 mg · L−1 respectively, were taken and analyzed for physical, chemical and microbiological contaminants. The RO plant was run once through over a span of 100 hrs at an operating pressure of 15 bar. TDS rejections were found to be more than 94% while permeate flux was measured to be 25.82 L · m−2 · hr−1 to 40.55 L · m−2 · hr−1. Results show that RO plant has a potential to remove physical, chemical and microbiological contaminants like Total Coliform and E. Coli in one step.

2

Speciation of heavy metals during co-composting of livestock manure

100%

Gul S. , Naz A. , Fareed I. , Khan A. , Irshad M.

Polish Journal of Chemical Technology

|

2015

|

tom Vol. 17, nr 3

19--23

EN

Heavy metals determination in manures provides beneficial information to predict the availability and the potential contamination of environment. Therefore, a study was carried out to investigate heavy metals changes in livestock manure during a co-composting process. The metals were stepwise fractionated into exchangeable, adsorbed, organically bound, carbonate precipitated and residual forms by extracting with 0.5M KNO3, de-ionized water, 0.5M NaOH, 0.05M Na2EDTA and 4M HNO3, respectively. During the extraction process, the amount of metals remained highly dependent on an extraction method and stage of manure composting. Extractions released heavy metals contents in the final composted manure as Zn > Cu > Pb > Cr > Ni > Cd. Irrespective of the days of composting, extracting agents differed in the order HNO3 > Na2EDTA > NaOH > KNO3 > H2O for all heavy metals. Higher concentrations of heavy metals were observed during the early stages of composting. Conversely, there was a progressive increase in the concentrations of K, Ca and Mg during composting of manure. Total C in the manure reduced with composting days.

3

Radiotracer investigations of municipal sewage treatment stations

86%

Farooq M. , Khan I. , Ghiyas-ud-Din , Gul S. , Palige J. , Dobrowolski A.

|

2003

|

tom Vol. 48, nr 1

57-61

EN

Tracer techniques, which are well-established methods in process dynamics studies in industry, were applied to investigate the dynamics of sewage treatment process. The concept of residence time distribution (RTD) was used to investigate the efficiency of the primary clarifier, aeration tank and secondary clarifier of a sewage treatment plant. Preliminary treatment and modeling of the tracer data was performed using the software DTS Pro Ver. 4.20. A big short - circuiting (by-passing) with a large volume of stagnant zones were found in the primary and secondary clarifiers, while no stagnant zone was detected in the aeration tank.

4

Adsorption characteristics of magnesium-modified bentonite clay with respect to acid blue 129 in aqueous media

72%

Hussain S. , Ullah Z. , Gul S. , Khattak R. , Kazmi N. , Rehman F. , Khan S. , Ahmad K. , Imad M. , Khad A.

Polish Journal of Environmental Studies

|

2016

|

tom 25

|

nr 5

EN

Locally available bentonite clay has been modified by magnesium and used to eliminate acid blue 129 from aqueous solutions. The adsorption was studied under different experimental conditions such as dye concentrations, temperature, and shaking time. The adsorption of the dye increased with time and followed the pseudo-first-order kinetic with rate constant “k” 0.126 min-1 at 283 K. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were calculated from the slope and intercept of the linear plots of ln K against1/T. Analysis of adsorption results obtained at temperatures of 283, 293, 303, and 313 K showed that the adsorption pattern on bentonite seems to follow Langmuir and Freundlih. The increase in temperature reduces adsorption capacity by magnesium-modified bentonite due to the enhancement of the desorption step in the mechanism. The activation energy of the adsorption process was found to be 3.55 kJ mol-1. The Mg-bentonite showed better adsorption than Ba and Al-bentonite. Our study reveals that abundantly available local clay may be used to eliminate dyes from aqueous solutions.