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1

Anaerobic treatment of industrial wastewater by UASB reactor integrated with chemical oxidation processes; an overview

100%
Yasar A., Tabinda A. B.
Polish Journal of Environmental Studies
|
2010
|
tom 19
|
nr 5
In order to upgrade the quality of anaerobically treated effluent to a level recommended for irrigation, integration of a UASB reactor with UV and AOPs (advanced oxidation processes) (Ozone, H2O2/UV, Fenton, and photo-Fenton) could be a better option for almost complete colour, COD removal, and disinfection of pathogens. High efficiency of the UASB can be maintained by proper process conditions, including temperature, sludge age, pH, hydraulic retention time, and gas-liquid-solid separator (GLSS) design. A fraction of the COD and colour is usually non-biodegradable and renders difficulty for anaerobic digestion. AOPs degrade the organic molecules and converting completely the organic compounds to non-toxic components such as CO2 and/or water. As far as disinfection is concerned, advanced oxidation processes are proved to be extremely effective in killing pathogens (total coliform, fecal coliform, fecal streptococci, salmonella, and E. coli) due to their strong oxidative characters. Although AOPs effectively accomplish pathogen elimination, re-growth of pathogenic microorganisms can take place in the treated effluent. Re-growth potential of pathogens provides helpful information about the quality of the treated water, which is very important in all possible reuse options. The combined application of AOPs with anaerobic treatment minimizes the chances of regrowth due to irreparable damage to nucleic acid. This review paper focuses primarily on the process conditions and treatment efficiency for UASB treatment systems, and to evaluate the advanced oxidation processes (AOPs) as an option for post treatment.
2

Urban emission patterns at a semi-arid site in Lahore, Pakistan

81%
Haider R., Yasar A., Tabinda A. B.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 1
The current research is an attempt to find out diurnal and monthly mean patterns of air pollutants, their interrelationships, and their dominant sources through hourly and monthly data analysis. Lahore is a semiarid region with low rainfall, hot and humid summers, and cold dry winters. Annually, the highest air quality index (AQI) (132 to 185) is observed from November to February due to inversion at low wind speeds (<1.5 m/s monthly average), low temperature (15ºC to 21ºC monthly average), and low solar radiation (104 to 140 W m-2 monthly averages). AQI remained low (74 to 85) from June to August due to relatively heavy rain, relatively high wind speed (1.59 to 1.85 monthly averages), dispersion due to high temperatures, high solar radiation, and summer vacations to schools. With an analogous diurnal trend, the AQI remains stumpy in daytime. The high CO/NOx ratio indicates that mobile sources are dominant contributors to NOx; and the low SO₂/NOx ratio indicates that point sources are dominant contributors to SO₂. CO has a significant positive correlation with NO, NO₂, NOx, CH₄, SO₂, and RH, and a negative correlation with O₃ and temperature. This explains why four-stroke petrol engines are common sources for CO, NO, NO₂, and NOx. PM₂.₅ has a significant positive correlation with SO₂, which explains why diesel engines are a common source for PM₂.₅ and SO₂. O₃ has a significant negative correlation with NO, NO₂, NOx, CH₄, CO, and RH; and has a significant positive correlation with temperature and solar radiation.
3

Heavy metal uptake and toxicity in tissues of commercially important freshwater fish (Labeo rohita and Wallago attu) from the Indus river, Pakistan

81%
Iqbal A., Tabinda A. B., Yasar A., Mahfooz Y.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 2
The purpose of this study was to evaluate the accumulation of heavy metals in the liver, skin, gills, and muscles of two freshwater edible fish species (Labeo rohita and Wallago attu) collected from Taunsa barrage of the Indus River in Pakistan. Fish samples were collected on a seasonal basis and were analyzed by atomic absorption spectroscopy. Gills and liver accumulated relatively higher heavy metal concentrations. All fish organs accumulated the highest metal content in winter and the lowest in summer. Heavy metals accumulated in the order Fe>Zn>Ni>Cu>Pb>Cr>As in the body of Labeo rohita and the tissues with the abundance were liver>gills>skin>muscles. Similarly, the sequence of heavy metal accumulation in Wallago attu was Fe>Zn>Cu>Ni>Cr>Pb>As, and the targeted tissues were gills>liver>skin>muscles. Heavy metal bioaccumulation was different in both species. Fe was the highest and As was the least accumulated heavy metal in both of these fish species. The tissues of Wallago attu accumulated higher concentrations of Ni (83%), Cu (64%), Cr (50%), Fe (2.95%), and Zn (26%) compared to tissues of Labeo rohita. However, Pb (67%) and As (22%) accumulation in tissues of Labeo rohita were higher compared to their concentrations in tissues of Wallago attu. Overall metal burden was 10% higher in Wallago attu compared to Labeo rohita. Heavy metal concentration in fish tissues were compared with FAO threshold values.
4

Biogas synthesis from leather industry solid waste in Pakistan

71%
Ijaz M., Tabinda A. B., Ahmad S. R., Khan W. U., Yasin N. A.
Polish Journal of Environmental Studies
|
2020
|
tom 29
|
nr 5
5

A comparison of engine emissions from heavy, medium, and light vehicles for CNG, diesel, and gasoline fuels

71%
Yasar A., Haider R., Tabinda A. B., Kausar F., Khan M.
Polish Journal of Environmental Studies
|
2013
|
tom 22
|
nr 4
Like other developing countries (Brazil, Argentina, and India) compressed natural gas (CNG) is becoming a popular vehicular fuel in Pakistan. Rapid shifting of diesel and gasoline vehicles to CNG has brought Pakistan the highest number of CNG vehicles in the world. To quantify a possible decrease in vehicular emissions for different types of vehicles, engine and fuel types were monitored for five parameters: SO2, CO, NO, hydrocarbons, and smoke opacity. Emissions from heavy vehicle engines shifting from diesel to CNG showed a decrease in HC (14 times), NO (2.8 times), and smoke opacity (3.2 times), while shifting diesel car engines to CNG resulted in reduced emissions of HC (24.6 times), NO (2.8 times), and smoke opacity (6 times). However, switching of light vehicles such as gasoline car engines to CNG released low emissions of HC (4.6 times), smoke opacity (1.2 times), SO2 (1.2 times), and CO (1.1 times), but an increase in NO (1.2 times) was observed. Similarly, a 4-stroke CNG rickshaw engine increased NO emissions by 1.4 times over a 4-stroke gasoline rickshaw engine.
6

Ozonation and photo-driven oxidation of ciprofloxacin in pharmaceutical wastewater: degradation kinetics and energy requirements

71%
Wajahat R., Yasar A., Khan A. M., Tabinda A. B., Bhatti S. G.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 3
Pharmaceutical wastewater has become an important source for emitting antibiotics into aquatic environments. However, this study aims to evaluate the potential of different advanced oxidation processes like ozonation, photolysis, and photo-catalysis for degrading a fluoroquinolone antibiotic ciprofloxacin (CIP) in real pharmaceutical wastewater. The raw wastewater contains a high concentration of organic content (COD: 603 mg/L, BOD: 116 mg/L) and significant concentration of CIP (7.91 mg/L). In ozonation, compared with the acidic and basic conditions, the degradation rate was faster under basic conditions and showed a competently degraded CIP (up to 98.7%) under the optimum pH 9 within 30 min, whereas photo-catalysis by using commercial anatase (TiO₂) is considered to be the most effective technique for decreasing the concentration of CIP up to 100% within 30 min under the optimized TiO₂ dose (1000 mg/L). The degradation rate was quicker and found to be several times faster than in direct photolysis. Furthermore, electrical energy per order was also calculated for all processes and was obvious by the results that photo-catalysis consume less energy of about 8.7 kWh/m3, for almost complete deduction of CIP.
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