Review on the progress of building-applied/integrated photovoltaic system

Environmental Science and Pollution Research - Integration of photovoltaic (PV) technologies with building envelopes started in the early 1990 to meet the building energy demand and shave the peak...     

Determination of toxic inorganic elements pollution in ground waters of Kahuta Industrial Triangle Islamabad, Pakistan using inductively coupled plasma mass spectrometry

The present study deals with the ground water quality assessment in Kahuta Industrial Triangle Islamabad, Pakistan. The objective of the study was to assess ground water quality against the drinking water standards for various toxic inorganic elements. Representative groundwater samples were collected and analyzed in the Water Quality Laboratory of Pakistan Council of Research in Water Resources (PCRWR) at Islamabad, Pakistan. The samples were run on ICP-MS (Inductively coupled plasma mass spectrometry), which has the capability to separate and quantify 70 elements at a time. One of the finding of study is that ICP-MS is a very good tool to analyze broad range of toxic inorganic elements to the level of parts per billion (ppb). World Health Organization drinking water standards shows that these toxic inorganic elements such as heavy metals even at this concentration level (ppb) are injurious to human health. This analysis indicated pollution of various toxic elements including Selenium. Vertical leachate through industrial waste septic tanks is identified as major cause of groundwater pollution in the Industrial Triangle. Monitoring of the septic tanks and groundwater quality in study area is suggested along with remedial measures.     

Evaluation of leaching characteristics and environmental compatibility of solidified/stabilized industrial waste

An attempt was made to judge the environmental compatibility, the governing leaching mechanism, and mobility patterns in a waste–cement solidified/stabilized matrix after 21 days of curing. The mixed sludge from a steel pickling facility was stabilized by ordinary Portland cement. Iron was the major leachable metal, along with Pb, Zn, and Mn. To characterize the leaching behavior, the mobility and mechanism of leaching were determined by diffusion leaching tests. In the solidified/stabilized matrix, the mobility of all the elements studied was reduced, and average to low mobility was observed. Values for the negative log of the effective diffusion coefficient of more than 12.5 were obtained for the metals. The dominant leaching mechanisms were surface wash off in the initial stage, followed by diffusion. The environmental performance of the solidified/stabilized product when considered in terms of mass leached over 64 days was found to be satisfactory for consideration for the safe disposal and reuse of waste.     

Indoor aerobiological pollution in certain indian domestic environments

The paper deals with bacterial and fungal populations and other pollutants in the indoors of slums, middle class, and upper class dwellings. Both allergenic and nonallergenic organisms have been observed to be higher in slums than in other dwellings. Further, females were more susceptible to various kinds of allergies than males.     

Study of the treatment effectiveness of a solidification/stabilization process for waste bearing heavy metals

The sludge from a steel processing unit bearing zinc, lead, iron, and manganese was solidified with ordinary Portland cement. The waste was stabilized in the specimens with a waste/binder ratio range of 0.16–4.0. On the basis of the available leaching and unconfined compressive strength, the performance of the solidified/stabilized waste was compared for different numbers of curing days. It was found that curing up to 28 days resulted in a performance improvement, as shown by less leaching of heavy metals and the increased unconfined compressive strength of the specimen. The treatment effectiveness of the solidification/stabilization process was assessed for the metals Pb, Zn, Fe, and Mn, and was found to be 89%, 95%, 74%, and 90%, respectively, for an optimum ratio of 4.0 after 28 days of curing.     

A review on management of chrome-tanned leather shavings: a holistic paradigm to combat the environmental issues

Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs.     

Implications of depletion of groundwater levels in three layered aquifers and its management to optimize the supply demand in the urban settlement near Kahota Industrial Triangle area, Islamabad, Pakistan

This study deals with the implications of depletion of groundwater levels in three layered aquifers and its management to optimize the supply demand in the urban settlement near Kahota Industrial Triangle area, located adjacent to the Soan River, Islamabad Pakistan. Initially, a groundwater 3-D steady-state flow model has been developed, calibrated to the known observed heads of 24 water wells, verified, and confirmed that convergence has actually arrived and hydraulic heads are no more changing. Later, the transient simulation was carried out with the constant discharge rates of groundwater by means of pumping wells, storage factor, porosity, and observed drawdown matched with the simulated drawdown that appears to fall in close agreement with a difference of 0.25 m. As such, the developed groundwater model has facilitated to understand, evaluate, and to predict regional trends of groundwater flow regimes and their ultimate utilization at a maximum rate of 4.5 million gallons/day for the growing urban settlement. The calibrated and verified model was then used to simulate the depletion of groundwater level, annual water balance, discharge versus time drawdown, and a temporal behavior of the system over an extended period of pumping. The modeling results indicate that, due to the pumping, the direction of flow has changed: first from groundwater regimes to the Soan River and then it is entirely reversed from the Soan River to the groundwater regimes as the drawdown started to deepen.     

Highlighting the implications of selenium dispersion from disposal of Kahota Industrial Triangle area, Islamabad, Pakistan using three-dimension solute transport model

This study highlights the implications of selenium (Se) dispersion in groundwater flow regimes of Kahota Industrial Triangle area located adjacent to the Soan River, Islamabad. Initially, a regional groundwater 3-D flow model has been developed, calibrated to the known observed heads of 24 water wells, verified, and confirmed that convergence has actually arrived to satisfy the steady state condition. Later, the transient simulation was carried out adding in the known recharge, storage factor, porosity, and observed drawdown matched with the simulated drawdown that appears to fall in close agreement with a difference of 0.25 m. As such the steady state groundwater model has facilitated to understand the mechanism of groundwater flow regimes in reference to the implications of selenium dispersion from disposal of Kahota Industrial Triangle area. Thirty-five water samples were collected mainly from the industrial water wells for the evaluation of heavy metals. Selenium being the major contributor of pollution has been short listed to monitor its dispersion using a solute transport model modular three-dimensional transport model (MT3D). Chemical parameters related to selenium characteristics including horizontal and vertical transverse dispersivity/longitudinal dispersivity, effective molecular diffusion coefficient and bulk density of the porous medium of aquifers have been used in MT3D contaminant transport model. MT3D is run for 30 years in steady state condition. As usual first run did not produce the exact field conditions. Therefore, the contaminant transport model is calibrated against the 32 values of observed selenium concentrations in boreholes by minor adjustments in the chemical parameter values. The final calibration has been achieved with residual value of 3.88 × 10^???5 Kg/m³. Seven hypothetical observation wells are used to monitor the selenium concentrations over a long-term period of time.     

Studies on lethal concentrations and toxicity stress of some xenobiotics on aquatic organisms

Three widely used xenobiotics pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (Butachlor) are evaluated for acute toxicity and stress behavior on freshwater fish (Heteropneustes fossilis, Clarias batrachus, Channa punctatus) and mosquito larvae (Culex pipiens fatigans). The experiment was carried out by medium treatment using intermittent flow-through system. Median lethal concentrations (LC50) were calculated by probit analysis. The LC50 values and 95% confidence intervals showed variable range for tested chemicals. Mosquito larvae generally appeared resistant than fish, while H. fossilis was found to be most sensitive. Stress signs in the form of behavioral changes are also observed. Both types of organisms are recommended as good bioindicator for the risk assessment of aquatic environment due to chemicals tested.