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The role of Photovoltaic technologies integrated or attached to the building envelope is crucial in managing the building energy demand. In this paper, the performance of PV technologies with the mounting methods of Building integrated and Free-standing (Building attached) is discussed for six different climate zone of the country. A PVGIS program proposed with three PV cell technologies (Crystalline Silicon, Copper indium diselenide, Cadmium Telluride) is used to evaluate monthly energy generation potential and losses of the 2 kWp grid-connected PV system at the latitude and 90°. A 2 kWp PV system is chosen for Economic Weaker Section (EWS) housing schemes depending upon the roof area. From the evaluation, the performance parameter has been estimated. A new parameter Energy Deviation (ED), is proposed to choose the best PV technology in terms of performance. The results of ED agree with the parameters Performance Ratio (PR) and Capacity Factor (CF) defined under the IEC Standard 61724. The potential generation of PV technologies at 90° varies from 41% (Warm and Humid) to 64% (Cold and Sunny) when compared with the latitude. In case of Cold and Sunny and Cold and Cloudy at 90°, the generation performance of Copper indium diselenide is found better in Building integrated and Free-standing mounting methods, respectively. For the remaining zones, Cadmium Telluride technology shows better results. The Percentage loss in the system is found to be minimum in the case of Cold and Sunny, varies between 17% and 25%, and maximum is found for Warm and Humid and varies between 23.2% and 33.4% for the proposed PV technologies. The grid feed-in energy from these EWS houses for all the technologies and climatic zones is found above 45%. It is seen that the combined energy generation from the envelopes (Roof, walls, and facades) makes the houses energy plus in nature. The study has important implications for the government to promote the building integrated Photovoltaic policies in the country.

Integration of photovoltaic (PV) technologies with building envelopes started in the early 1990 to meet the building energy demand and shave the peak electrical load. The PV technologies can be either attached or integrated with the envelopes termed as building-attached (BA)/building-integrated (BI) PV system. The BAPV/BIPV system applications are categorized under the building envelope roof and facades as PV-roof, PV-skin facade, PV-Trombe wall, PV claddings, and louvers. This review covers various factors that affect the design and performance of the BAPV/BIPV system applications. The factors identified are air gap, ventilation rate, a tilt angle of PV shading devices, adjacent shading, semitransparent PV (STPV) glazing design, cell coverage ratio (CCR), transmittance, window to wall ratio (WWR), and glazing orientation. Furthermore, the results of the possible factors are compared to building locations. This review article will be beneficial for researchers in designing the BAPV/BIPV system and provides future research possibilities.

The Phase Change Material (PCM) reduces thermal load and increases comfort inside the building. The paper discusses how and where PCM’s are used in Building Integrated Photovoltaics (BIPV), their impact on the performance of the PV module and built environment. In this review paper, BIPV-PCM system is categorized into two parts either Ventilated or Non-ventilated. Further, the thermophysical properties and temperature reduction in PV modules has been discussed. From the study, it is seen that most of the PCM’s were encapsulated with PV modules and building envelopes at the macro level. A significant reduction in temperature of modules and building envelopes occurs in both the categories is observed. However, the implementation of BIPV-PCM at a large scale and its economic viability is to be examined by the researchers in upcoming years.

One of the applications of PV technology is to either integrate or attach it with the building envelopes. In this paper, a simulation has been performed for Economic Weaker Section (EWS) housing schemes to see the impact of roof attached PV modules on room operative temperature (Topt) and compare it with the base case roof without PV modules. A Non-conditioned building is simulated for the composite climate of Indore in the DesignBuilder software. For thermal comfort analysis, a simulation for the summer months has been performed (April-September). It has been observed that compared to No PV Roof 1 (RCC) as a base case, the maximum reduction in room operative temperature of PV Roof 1 (RCC) case is 3 °C and 3.7 °C for PV Roof 2 (stone). Due to the reduction in Topt, the simple payback period (SPP) calculated for PV Roof 1 (RCC) is 5.77 yrs and for PV Roof 2 (Stone) it is 4.32 yrs. The Net CO2 emission gets reduced by 30% and 50%, respectively, for BAPV Roof 1 and Roof 2 compared to the base case. The BAPV cases achieve the Net CO2 mitigation of 109 tonnes and 113 tonnes. This study shows that PV modules' passive behavior reduces the Topt and provides credibility to the low-cost materials in the building construction.

This paper assessed an Environmental Impact Assessment (EIA) for Municipal Solid waste landfill sites of two different regimes. The study deals with two sites of entirely different geographical areas and waste generation pattern. India enforced Municipal Solid Waste Management and Handling rules,2000 and its subsequent amendments for all the cities and towns having entirely physical and climatically different conditions for solid waste management. Still, MSW dumped in open places without any treatment results in severe environmental impacts in and around the surrounding areas, making it essential to assess its impact. Quantitative assessment of ground water, soil and air quality was determined. Whereas in this study, we used Rapid Impact Assessment Matrix (RIAM), because all the components and parameters can easily be integrated into one platform, applying the criteria that were considered to be the most significant in the evaluated cases to compare the environmental and social impact of the two MSW dump site. The RIAM results revealed that the method could be used for comparison and ranking of separate and distinct areas, based on their negative or positive impact. No significant difference was observed in the scoring of the two sites, i.e.the Indore city landfill obtained slightly more negative scoring (100%) than Srinagar landfill (96.6%). The decomposition of waste seems to be more in Indore than in Srinagar due to cold climatic zone. The paper reveals the adverse impact of dump sites on the nearby areas in both the regions.

Reduction in post-harvest losses of fresh vegetables is a major objective of most of the cold chain programs. Drying is also an effective tool for reducing post-harvest loss. However, the existing industrial drying techniques are energy intensive in operation results emission of high green-house gases. Low-grade waste heat recovered from condenser of refrigeration system could be utilized for drying applications. The process consists an effective utilization of heat, obtained by the condensing unit of a refrigeration system in an intermittent manner with no external energy requirement. An experimental approach of vapour-compression based-refrigeration system has been performed for drying of onion sample. The drying was performed at average temperature of 43 °C. Moisture content was reduced to 12% (wb) after 24 h of drying. Average values of drying rate and SMER were found as 0.013 kg/h and 0.196 kg/kWh, respectively, at the mass flow rate of 0.268 kg/s. The overall drying process is energy efficient. This could be a promising future replacement of current industrial drying systems which are relatively more energy intensive.

The goal of this paper was to evaluate the effectiveness of solar photo-Fenton (Fe2+/H2O2/UV–vis) treatment that is able to degrade heavy metal contents (Cu, Cd, Cr, Fe, Ni, Pb and Zn) and pathogenic microbial population (Fecal Coliform/100 mL) present in municipal wastewater with minimal iron and H2O2 concentrations. Photo-Fenton experiments were performed in a solar parabolic trough reactor (PTR). Three level factorial design and response surface method (RSM) was used for characterization and optimization of the process in which a response of interest is influenced by four key variables (pH, solar exposure time, catalyst dose (Fe2+/Fe3+), and amount of oxidant (H2O2)). The performance of advanced oxidant process was investigated in terms of percentage degradation of heavy metals and Fecal Coliform (FC) bacteria present in municipal wastewater. The result shows that variables have significant effect on the degradation process of municipal wastewater. Photocatalytic degradation efficiency was found to be dependent on optimized catalyst dose (Fe2+ 100 mg/L) and amount of oxidant (H2O2 500 mg/L). Analysis of variance (ANOVA) exhibited a high coefficient (R2 = 0.72–0.89), thereby indicating a satisfactory fit between the experimental results. The statistical model of solar photo-Fenton has shown excellent performance. Excessive hydrogen peroxide and iron have shown scavenging effects on hydroxyl radicals and reduced degradation of micro-pollutants present in wastewater. © 2016 American Institute of Chemical Engineers Environ Prog, 2016

Leather industry generates huge amount of chrome-containing leather solid waste which creates major environment problems to tanners worldwide. Chrome-tanned leather solid waste is primarily chromium complex of collagen protein. The presence of chromium limits its protein application in animal feed industry. The purified protein hydrolysate with zero chromium could be used in poultry feed. In this study, an attempt has been made to assess performance of poultry with purified protein hydrolysate as a feed derived from chrome-tanned leather waste as partial replacement of soyabean meal as a sole source of protein for growing broiler chickens. Growth study was conducted to evaluate the effect of feeding protein hydrolysate on performance and physiochemical characteristics of meat of broiler chickens. Two experimental diets containing various levels of protein hydrolysate (EI-20 % and EII-30 %) were evaluated. The comparative study was performed as control with soyabean meal. Daily feed intake, body weight gain and feed conversion ratio were measured from day 8 to day 35. At the end of the study, birds were randomly selected and slaughtered to evaluate for physiochemical characteristics of meat. Diet had significant effects on feed intake and body weight gain. Birds fed with 20 and 30 % protein hydrolysate consumed 9.5 and 17.5 % higher amount of feed and gained 6.5 and 16.6 % higher than soyabean meal-fed birds. The current study produced evidence that protein hydrolysate can replace up to 75 % of soyabean meal in broiler diets without affecting either growth performance or meat characteristics.

The performance of the Photovoltaic (PV) module as a building material is analyzed by predicting the hourly variation in the room temperature compared to base case (conventional material). A computer simulation model of Fourier admittance method is used for the analysis. The average temperature fluctuation of PV roof and PV wall building compared to base case is 6.58°C and for PV wall 2.91°C respectively. The total daily energy generation from PV wall is found in the range of 6.7 kWh to 11.86 kWh, for PV roof its 17.24 kWh to 22 kWh. Due to temperature fluctuation the max additional daily cooling load obtained in PV roof case is 94.7 kWh and 41.97 kWh for PV wall.

This paper deals with the use of different methods to predict methane generation on an open dump site. Methane recovery data obtained on site as part of a research program being carried out at the Devguradia dumpsite, Indore, is analyzed and used to obtain field methane emission in three seasons. Field data from Municipal solid waste (MSW) dump site are presented and discussed measured in-situ technique i.e. using close chamber methods. The Intergovernmental Panel on Climate Change (IPCC) Default Method (DM) and First order Decay (FOD) method is used to estimate methane generation. It is found that despite the assumptions and the simplicity of the adopted procedures, the values methane obtained are slightly varying to those measured in the field. The values obtained were 4.5, 2.9 and 0.35 Gg/y respectively.

In this study, municipal wastewater was treated by two types of advanced oxidation processes—photocatalytic (solar radiation/TiO2) and photocatalytic with oxidation (solar radiation/TiO2/H2O2). Response Surface Method (RSM) was used for characterization and optimization of both the processes in which a response of interest is influenced by several variables. The factors study includes pH, catalyst dose, and amount of oxidant. The performance of photocatalytic and oxidant process was investigated in terms of percentage degradation of wastewater. The result shows that catalyst dose and amount of oxidant have significant effect on the degradation process of municipal wastewater. Photocatalytic degradation efficiency was found to be dependent on optimized catalyst dose (1 g/L) and amount of oxidant (30 mL/L). Analysis of variance (ANOVA) exhibited a high coefficient (r2 = 0.912–0.996), thereby indicating a satisfactory fit between the experimental results. The statistical model of solar radiation/TiO2/H2O2 has shown excellent performance. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1629–1639, 2015

The combined effects of three independent variables (carrier filling ratio, aeration rate and reactor run time (RRT)) were evaluated in a continuous moving bed biofilm reactor (MBBR) through central composite design (CCD) of the response surface methodology (RSM) for experimental design, analysis and process optimization for municipal wastewater treatment processes. A low-cost polystyrene biocarrier was designed and its efficiency in terms of organic and nutrient removal was evaluated in an MBBR. A mathematical–statistical tool represented by CCD was employed to assess the interactive effects of the three key independent operational parameters, inclusive of biocarrier filling ratio (0–70%), aeration rate (0.21–0.63 m3 h–1) and RRT (1–15 days), on the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total Kjeldahl nitrogen (TKN), total phosphorus (TP) and turbidity. The maximum efficiency obtained was at carrier filling rate 50%, aeration rate 0.42 m3 h–1 and RRT of 9 days, respectively. The results obtained for COD, BOD, TKN, TP and turbidity were 91.6, 92.9, 72.0, 55.0 and 46.0%, respectively. This study provides valuable information about interrelations of process parameters at different values of the operating variables. The results illustrate that this statistical tool could be effectively utilized for effluent organic load, nutrient and turbidity removal.

The present study is targeted on photocatalytic removal of metal ions from wastewater. Photoreduction, deposition, and dark adsorption of Cr 6+ ,C u 2+ ,N i 2+ , and Zn 2+ metal ions have been investigated using TiO2 with UV-irradiated. Also investigated that citric acid as a hole scavenger and hydrogen peroxide as a oxidant at pH values 2, 4, 6‐8, and 10. The modeling of metal species has been performed and speciation is used as a tool for discussing the photoreduction and deposition trends. The modeling of metal species at different pH values has been performed. It was observed that the photocatalytic process was effective in removing most of the metal ions in specific reaction circumstances. The maximum reduction and deposition of Cr and Cu 2+ were found to be favorable at acidic pH 2‐4, while Ni 2+ and Zn 2+ reductions were found to be most suitable at neutral to alkaline pH 10. The photocatalytic reduction and deposition trend of the metal ions prove the theoretical thermodynamic predictions about a reaction time period (5 h). Keyword: Photocatalysis; Citric acid; Hydrogen peroxide; Metal ions; PH; Modeling; Speciation; Adsorption; Reduction; Deposition

Moving bed biofilm reactor (MBBR) incorporates benefits provided by both attached and suspended growth systems. It is an advanced high rate wastewater treatment technology with high treatment efficiency; low capital, operational, maintenance and replacement cost; single reliable and robust operation procedure. Moreover, this technology is applicable to wide range of wastewater flows ranging from 10,000 to 150,000 m3 day−1. The MBBR has proved to be effective in removing up to 90 % chemical oxygen demand and 95 % biochemical oxygen demand with nutrients from the effluent stream at optimum condition, provided there is sufficient retention time. It is a cost-effective way of upgrading existing wastewater treatment system as it is efficient, compact and easy to operate. This process can be provided for new sewage treatment works or for retrofitting existing wastewater treatment plants where a higher treated effluent standard is required without any running and capital cost. The performance of MBBR depends on the percent of media provided in the reactor, surface area of the biocarrier, dissolved oxygen and the organic loading. Various mathematical models are also described in this review paper which is generally used to calculate the reactor volume, effluent organic concentration and substrate removal rate.

The present study is targeted at the feasibility of photocatalytic treatment of wastewater containing metal ions. The relatively newest of which is photo catalysis with titanium dioxide which may also be used, plus hydrogen peroxide as a hole scavenger to improve the treatment rate. In this study, photocatalysis/hydrogen peroxide processes had been employed for the removal of four metal ions Cr, Cu, Ni, and Zn present in the wastewater. Experiments were carried out to find an optimum dose of H2O2, used as hole scavenger. The absorption and reduction of the metal ions at different pH values (7.2, 2, 4, 6, 8 and 10) were also investigated. The detention time was kept constant (300 min). Results indicated that at pH 2, complete reduction was achieved for Cr. However, Cu, and Zn reduced completely even at alkaline and natural pH in a minimum time period; and 94.8% reduction of Ni at the alkaline pH was obtained by solar radiation. On the other side without solar radiation, the percentage of removal of...

The present study is targeted on the feasibility of photocatalytic treatment of industrial wastewater containing metal ions. Photoreductive deposition of metal ions using solar energy irradiated TiO2, has been investigated in presence of citric acid as a hole scavenger. Treatment studies have also been performed at pH values 2, 4, 7, 8, and 10 to determine optimum reaction conditions. Results showed that at the pH value of 2, 100% reduction was achieved for Cr(VI) in a minimum time period. A maximum removal of 95.5% was achieved for Ni(II) at the pH value of 10.

This article describes the photocatalytic reduction and deposition of four metal ions Cr(VI), Ni(II), Zn(II), and Cu(II) present in the wastewater from a chrome plating industry using solar energy irradiated TiO2. A parabolic trough reactor was used to carry out the reaction. Experiments were carried out to find an optimum dose of hole scavenger used (citric acid). The adsorption and reduction of the metal ions at different pH values was also investigated. It was observed that the solar photocatalytic process was effective in removing most of the metal ions in specific reaction conditions. Alkaline pH was found to be more suitable for removal of nickel and zinc. However, Cr(VI) reduced completely even at catalyst concentrations as low as 0.5 mg/L at pH 2. Maximum reaction was completed in the first 4 h of solar exposure. © 2008 American Institute of Chemical Engineers Environ Prog, 2008

The present study is targeted on solar photocatalytic removal of metal ions from wastewater. Photoreductive deposition and dark adsorption of metal ions Cu(II), Ni(II), Pb(II) and Zn(II), using solar energy irradiated TiO 2 , has been investigated. Citric acid has been used as a hole scavenger. Modeling of metal species has been performed and speciation is used as a tool for discussing the photodeposition trends. Ninety-seven percent reductive deposition was obtained for copper. The deposition values of other metals were significantly low [nickel (36.4%), zinc (22.2%) and lead (41.4%)], indicating that the photocatalytic treatment process, using solar energy, was more suitable for wastewater containing Cu(II) ions. In absence of citric acid, the decreasing order deposition was Cu(II) > Ni(II) > Pb(II) > Zn(II), which proves the theoretical thermodynamic predictions about the metals.

A moving bed biofilm reactor (MBBR) coupled with solar parabolic structured system has been designed and developed to get the maximum organic load removal and microbial disinfection from the wastewater. The effluent was first subjected to organic degradation in MBBR (with optimized carrier filling rate of 30%) followed by the bacterial degradation using solar energy in parabolic trough and the changes in values of parameters like pH, turbidity, chemical oxygen demand (COD), bio-chemical oxygen demand (BOD) and microbial count were monitored. The titanium dioxide (TiO 2 ) was used as a photocatalyst for the removal of organic load from the wastewater but in optimized conditions. At optimum dose of 1.0 g/L of TiO 2 and pH value of 7.6, maximum COD removal of 69% and 13% was achieved at sunny days (solar irradiation 400–700 W m −2 ) and cloudy days (solar irradiation 170–250 W m −2 ) respectively within 5–6 h solar irradiation time. The results obtained showed that it is possible to decrease in six logarithms (log) the concentration of TC and FC within only 240 min of solar exposure. Moreover, this process can offer economically reasonable, chemical free and practical solution to the processing of municipal wastewater where solar intensity is readily available and can be used for making zero liquid discharge (ZLD) an effective reality.

A laboratory scale parabolic trough collector has been tested for photocatalytic reaction application to wastewater treatment under different reaction conditions. The photocatalytic reduction of Cr(VI) to Cr(III), using TiO2 suspensions under solar irradiation, has been investigated. The influence of reaction conditions has been illustrated using an organic additive (citric acid) in varying doses and also by performing the reaction at different pH values and doses of TiO2. An attempt has also been made to investigate the reuse performance of the photocatalyst. The rate of reduction was found to increase steadily with increasing concentration of organic additive, TiO2 dose and decreasing pH. Complete reduction of Cr(VI) to Cr(III) was achieved in 2 h and very low catalyst concentration at pH 2. The reuse studies showed that the catalyst can be used 2–3 times for lower Cr(VI) concentrations.

The present study is targeted on the effect of pH on solar photocatalytic removal of metal ions from wastewater. Photoreductive deposition and dark adsorption of metal ions Cu(II), Ni(II), Pb(II) and Zn(II), using solar energy irradiated TiO 2 , has been investigated at pH values 2, 4, 7, 8 and 10. Modeling of metal species at the studied pH values has been performed and speciation is used as a tool for discussing the photodeposition. The decreasing order of metal deposition at pH 2 and 4 was found to be Pb(II) > Cu(II) > Ni(II) ≅ Zn(II). In the neutral and alkaline pH conditions (pH 7, 8 and 10) the order was Cu(II) > Zn(II) > Ni(II) > Pb(II).

Geopolymerization is a developing field of research for utilizing solid waste and by-products. It provides a mature and cost-effective solution to many problems where hazardous residue has to be treated and stored under critical environmental conditions. Geopolymer involves the silicates and aluminates of by-products to undergo process of geopolymerization. It is environmentally friendly and need moderate energy to produce. This review presents the work carried out on the chemical reaction, the source materials, and the factor affecting geopolymerization. Literature demonstrates that certain mix compositions and reaction conditions such as Al2O3/SiO2, alkali concentration, curing temperature with curing time, water/solid ratio and pH significantly influences the formation and properties of a geopolymer. It is utilized to manufacture precast structures and non-structural elements, concrete pavements, concrete products and immobilization of toxic metal bearing waste that are resistant to heat and aggressive environment. Geopolymers gain 70% of the final strength in first 3–4 h of curing.

Aim : To evaluate the antifertility activity of triterpenes isolated from Albizia lebbeck (L.) Benth pods in male albino rats. Methods : Oral administration of triterpenes isolated from Albizia lebbeck pods at the dose level of 50 mg/rat/day for 60 days. Testicular sperm count, epididymal sperm count and motility were assessed. Biochemical and histological analysis were performed in blood samples and reproductive organs. Results : Oral administration of triterpenes did not cause any significant change in the body weights but a significant reduction in the weight of reproductive organs i.e. testis, epididymides, seminal vesicle and ventral prostate were observed. Testicular sperm count, epididymal sperm count and motility were significantly reduced (p

An attempt of response surface methodology (RSM) has been made for more effective utilization and optimization for considerable reduction of operational conditions such as reaction time, aeration time, energy consumption, etc. for municipal wastewater treatment process using moving bed biofilm reactor (MBBR). A mathematical-statistical model was developed for the second-order response surface through the fit of a polynomial function and a central composite design (CCD) in the form of a full factorial design. CCD was employed to assess the interactive effects of the three main independent operational parameters, including biocarrier filling rate (0-70 %), aeration rate (0.21-0.42 m(3) h(-1)), and reactor run time (1-15 days), on the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total Kjeldahl nitrogen (TKN). Analysis of variance expressed a high coefficient of determination (R (2) = 0.84-0.95), thereby indicating that the model is significant. Using a desirability function for the highest COD (93 %), BOD (96 %), and TKN (69 %) removal, the optimum carrier filling rate, aeration rate, and reactor run time were identified to be 40 %, 0.21 m(3) h(-1), and 7 days, respectively. It shows that RSM can be a suitable method to optimize the operational parameters of MBBR with enhanced removal efficiency and less power consumption.

Leather processing discharges enormous amount of chrome containing leather solid waste which creates a major disposal problem. Chrome-tanned leather solid waste is a complex of collagen and chromium. The presence of chromium limits protein application in fertilizer industry. The purified protein hydrolysate with zero chromium could be used as a nitrogen source for fertilizer formulation. In this study, an attempt has been made to employ purified protein hydrolysate derived from chrome-tanned leather shavings (CTLS) in formulation of fertilizer. The formulated fertilizer (1–3 t ha(-1)) is employed as nitrogen source in production of soybean. Plant growth study demonstrates that formulated fertilizer dosage 3 t ha(-1) produced similar effects of commercial fertilizer-treated plants. Application of formulated fertilizer yielded higher seed in plant than commercial fertilizer.

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.

Photocatalysis has been a widely studied technology since the 1970s. Many investigations have been carried out with the aim of understanding the fundamental processes and enhancing photocatalytic efficiencies especially for water, air, and soil pollution control. In this comprehensive paper, studies focused on the treatment of hazardous wastewater (bearing heavy metals and organic compounds) by photocatalysis and the effects of various parameters such as pH, light intensity, dissolved oxygen, etc., are reviewed. In addition, the design features and efficiencies of various photoreactors used for this process are discussed. Some studies on the economic analysis of photocatalytic systems are also included. It can be concluded that the photocatalysis process is suitable for the treatment of drinking water and industrial wastewater. Also, harvesting the energy of the sun for photoreactions would make it a cleaner and more cost-effective treatment method.

This paper presents the study of the immobilization of heavy metals like Pb, Fe, Mn, Cu and Zn by fly ash based geopolymers. The purpose of this study was to investigate the effectiveness of fly ash based geopolymeric solidification/stabilization technology. For S/S of waste, geopolymer as a binding agent was mixed with waste at different ratios. For initial waste characterization, contaminants concentration and some physical waste characterization such as dry density, bulk density, specific gravity, porosity, moisture holding capacity, and moisture content were determined. Waste and geopolymer mixture were cured for 7 and 28 days to study the effect of curing days on the solidified/ stabilized product. Diffusion leaching test was performed on the geopolymers containing industrial sludge to determine the leaching mechanism of binders to entrap the waste constituents within their matrix. Movement of the elements was identified with the help of leachability index. S/S through geopolymer was found to be effective in immobilizing toxic metals present in the sludge. Zn was 100% and other metals like Pb, Fe, Mn and Cu were in the range 80-99% immobilized. The order of fixation of metals was ZnCuFeMnPb.

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.

In this paper, an effort has been made to understand the factors, which affect fixation of heavy metals in solidified/stabilized matrix. Various aspects related to the solidification/stabilization of different heavy metals (Ar, Ba, Cu, Cr, Pb, Zn, Hg) are reviewed. A comparative study of different binders for the fixation of each metal has also been carried out to suggest the most suitable binder, pretreatment required for the metal. Valence, speciation, pH and other factors are also considered while reviewing metal retention capacity of different matrix.

The current work is related to inorganic species in sludge generated from Common Effluent Treatment Plant contaminated with hazardous wastes at relatively high concentration. The environmental sensitive metals studied in the sludge are Pb, Fe, Ni, Zn and Mn. The solidification/stabilization (S/S) of heavy metals within fly ash-cement-based matrix was conducted for low cost treatment and reuse of sludge. The study examines the strength of the S/S product by predicting the effect of supplementary cementing material from efficiency factor (k) at 60 degrees C curing temperature. The leaching test was performed at two different pH 7 and 4 to determine the efficiency of heavy metal immobilization. It was observed that replacing 76% OPC by 56% fly ash and 20% sludge for 28 days curing period shows increase in strength as well as rate of stabilization for zinc, iron and manganese at pH 7, lead and nickel were stabilized by 79 and 82%, respectively. Environmental stress test was performed to evaluate the tolerance of extreme adverse environmental condition.

Solidification/stabilization (S/S) of hazardous sludge from steel processing plant has been studied. Mechanical strength and leaching behavior test of solidified/stabilized product was performed. Mechanical strength decreases with increase in waste content. Pb, Zn, Cu, Fe and Mn could be considerably immobilized by the solidification/stabilization process. The elements least immobilized were Na, K, and Cl. Leaching of heavy metals in the S/S matrix can be considered as pH dependent and corresponding metal hydroxide solubility controlled process. Geochemical modeling was performed for the prediction of speciation. On the basis of test results, mobility and mechanism of leaching was assessed. Dominant leaching mechanism was surface wash off in the initial stages followed by diffusion for Pb, Zn, Cu, Fe and Mn. Diffusion coefficient was above 11.5 indicating low mobility in the cement matrix.

Solidification/stabilization is accepted as a well-established disposal technique for hazardous waste. As a result many different types of hazardous wastes are treated with different binders. The S/S products have different property from waste and binders individually. The effectiveness of S/S process is studied by physical, chemical and microstructural methods. This paper summarizes the effect of different waste stream such as heavy metals bearing sludge, filter cake, fly ash, and slag on the properties of cement and other binders. The factors affecting strength development is studied using mix designs, including metal bearing waste alters the hydration and setting time of binders. Pore structure depends on relative quantity of the constituents, cement hydration products and their reaction products with admixtures. Carbonation and additives can lead to strength improvement in waste-binder matrix.

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.

An attempt has been made to treat the wastewater containing a combination of inorganic contaminants to take the advantage of solar photocatalytic redox reactions. Synthetic wastewater is prepared containing substantial heavy metals to obtain a simultaneous reduction of both the wastewater components. The reaction is also attempted at different pH values to optimize the same. The metals in the waste combination are Cr, Ni, Zn, and Cu. Dark adsorption reactions are also performed along with the sunlight irradiation, in order to understand the process in detail. Results show that significant chromium and copper are the metals which are significantly reduced as compared to the other two metals studied. Chromium showed maximum reduced in the acidic pH range whereas the other metals were reduced in the alkaline and neutral pH ranges. The results provide a cost-effective method to remove organic and inorganic pollutants simultaneously in the simulated wastewater through photocatalytic.

There are great interests in photocatalytic oxidation of contaminants using advanced oxidation processes (AOP) based on photocatalytic oxidation in recent years. The main aim of the paper is to develop a method which takes care of energy and water conservation together. The study was performed on photocatalytic disinfection of total coliform (TC) bacteria as water microbial pollution and reducing the chemical oxygen demand (COD) as organic pollution index using catalytic and oxidant in present of sun light. The municipal wastewater was monitored for TC and in then was irradiated with solar light, solar light/TiO2, and solar light/TiO2/H2O2. Various parameters such as contact time, pH, and different concentration of TiO2 and H2O2 were studied for their effect on reaction process. The result showed that in presence of solar light, catalyst, and oxidant, very effective disinfection and reduction of TC and COD took place. 95.2% and 97% of TC and COD were reduced by irradiation for 240-300 min. Based on the re...

This study has focused on treatment of the metal ions, which have infinite lifetimes and build up their concentrations in food chains to toxic levels. Many researches have been performed about use of photocatalysis processes in treatment of industrial wastewater. The additional advantage is coming from sensitivity of the Cr(VI) photo reduction to the surface catalytic effects or to the presence of an additional electron donor and acceptors; then, a synergistic effect was observed in two- or multi-component systems. The efficiency of total chromium reduction by photo catalytic treatment under UV-light in different degradation systems, UV, TiO2/UV, H2O2/UV, TiO2/citric acid/UV, and TiO2/H2O2/UV, was studied and compared. Even when the TiO2/citric acid/H2O2/UV reaction happened to be the most efficient process, both homogeneous and heterogeneous photocatalysis can be considered as suitable methods to reach the complete mineralization of the solutions. Maximum treatment efficiency of total chromium reduction with increasing citric acid concentration from 20 to 80 mg/l was reduced to 62%, 76.7%, 77.91%, and 100%, and with increasing H2O2 concentration from 20 to 100 ml/l was reduced to 40.57%, 41.84%, 50.77%, 61.03%, and 100%, which is more efficient than the H2O2/UV process. Finally, the combination of TiO2/citric acid/H2O2/UV result was observed more efficient than the TiO2/citric acid and TiO2/H2O2/UV processes in the solutions.

Photocatalysis process, as an environmental application, is a relatively novel subject with tremendous potential in the near future. A number of studies determine the economic viability of applying various ultraviolet advanced oxidation processes for the purpose of degradation and destroying of various pollutant solutions. The present paper reviews the treatment of hazardous wastewater bearing organic compounds and the effects of various parameters such as pH, initial concentration, mass of catalyst, wavelength, light intensity, electron acceptor, temperature, etc., with the treatment cost for different reactor type. This study investigates the effect of various types of waste-water treatment parameters and the treatment cost for various designs of photocatalytic reactors, using both solar and artificial light, have been proposed for their different types of pollutants.

Department of Industrial Chemistry, Guru Nanak Khalsa College, Yamuna Nagar-135 001, Haryana, India Department of Chemistry, Haryana Engineering College, Jagadhari-135 003, Haryana, India Manuscript received 26 February 2008, revised 15 October 2008, accepted 12 November 2008 A simple and rapid extractive spectrophotometric method for micro determination of molybdenum using thiocyanate as a complexing agent has been worked out for industrial, environmental and soil samples. The Mov- thioqanate complex is extracted into 2,2' -dipyridyl in chloroform. The vermilion colour of the extract is measured at λmax505 nm against a similarly prepared reagent blank. The 1: 4 (Mo : SCN) complex is found to be ~table for more than one hour in the extract and obeys Beer's law over the concentration range of 0-11 µg Mo ml-1. The molar absorptivity and Sandell's sensitivity of the proposed method are found to be 1.24 x 104 dm3 mol-1 cm-1 and 0.0075 µg Mo cm-2, respectively. A large number of cations, anionsand complexing agents of major analytical importance such as Revll, Crlll,VI, Cull, Zrlv, Mnll, Nill, Fcll,lll, Wvl, Uvl, Vv and platinum metals, sulphate, chloride, fluoride, bicarbonate, phosphate. tartrate and EDTA do not interfere. Only oxalate, acetate, hydrogen peroxide, tin, cobalt, bismuth, titanium, osmium and ruthenium interfered in the procedure. The method has been applied satisfactorily for the determination of molybdenum in varieties of samples.