Real time remote monitoring of air pollutants and their online transmission to the web using internet protocol

Recent advances in both information and sensor technologies have enabled the development of Real Time Remote Monitoring (RTRM) capabilities for environmental management. An online and real time remote monitoring system for air pollution has been designed and installed at a traffic police station at Punjagutta in Hyderabad, India. The system is optimized using electrochemical sensors and a real time particulate matter analyzer. The system also monitors meteorological parameters such as temperature, humidity, rainfall, barometric pressure, wind speed and wind direction. The system periodically monitors both pollution and meteorological parameters at pre- programmed intervals of hr during peak periods and 1 hr during non peak periods of the day and continuously uploads to a predestinated web site (www.appcb.org/home.htm) using File Transfer Protocol. The web site renders a quick, simple and graphical display of air pollution levels and meteorological parameters and their significance to humans. The present paper highlights design considerations of a pollution monitoring system, system hardware and software requirements and practical limitations and future directions for real time remote monitoring of air pollution.     

Concentrations of cadmium and lead heavy metals in Dardanelles seawater

Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary experiments the optimal analytical condition for oxine concentration was found to be 2.10⁻⁵ M, at pH 7.7, the accumulation potential was −1.1 V, and the initial scannig potential was −0.8 V. The peak potentials were found −0.652 V for Cd and −0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification (LOQ) were found to be by voltammetry as 0.588 and 1.959 μg l⁻¹ (RSD, 5.50%) for Cd and 0.931 and 3.104 μg l⁻¹ (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained.     

Serial Correlation and Inter-annual Variability in Relation to the Statistical Power of Monitoring Schemes to Detect Trends in Fish Populations

We studied the effects of inter-annual variability and serial correlation on the statistical power of monitoring schemes to detect trends in biomass of bream (Abramis brama) in Lake Veluwemeer (The Netherlands). In order to distinguish between 'true' system variability and sampling variability we simulated the development of the bream population, using estimates for population structure and growth, and compared the resulting inter-annual variabilities and serial correlations with those from field data. In all cases the inter-annual variability in the field data was larger than in simulated data (e.g. for total biomass of all assessed bream sigma = 0.45 in field data, and sigma = 0.03-0.14 in simulated data) indicating that sampling variability decreased statistical power for detecting trends. Moreover, sampling variability obscured the inter-annual dependency (and thus the serial correlation) of biomass, which was expected because in this long-lived population biomass changes are buffered by the many year classes present. We did find the expected serial correlation in our simulation results and concluded that good survey data of long-lived fish populations should show low sampling variability and considerable inter-annual serial correlation. Since serial correlation decreases the power for detecting trends, this means that even when sampling variability would be greatly reduced, the number of sampling years to detect a change of 15%.year(-1) in bream populations (corresponding to a halving or doubling in a six-year period) would in most cases be more than six. This would imply that the six-year reporting periods that are required by the Water Framework Directive of the European Union are too short for the existing fish monitoring schemes.     

Review of state of the art methods for measuring water in landfills

In recent years several types of sensors and measurement techniques have been developed for measuring the moisture content, water saturation, or the volumetric water content of landfilled wastes. In this work, we review several of the most promising techniques. The basic principles behind each technique are discussed and field applications of the techniques are presented, including cost estimates. For several sensors, previously unpublished data are given. Neutron probes, electrical resistivity (impedance) sensors, time domain reflectometry (TDR) sensors, and the partitioning gas tracer technique (PGTT) were field tested with results compared to gravimetric measurements or estimates of the volumetric water content or moisture content. Neutron probes were not able to accurately measure the volumetric water content, but could track changes in moisture conditions. Electrical resistivity and TDR sensors tended to provide biased estimates, with instrument-determined moisture contents larger than independent estimates. While the PGTT resulted in relatively accurate measurements, electrical resistivity and TDR sensors provide more rapid results and are better suited for tracking infiltration fronts. Fiber optic sensors and electrical resistivity tomography hold promise for measuring water distributions in situ, particularly during infiltration events, but have not been tested with independent measurements to quantify their accuracy. Additional work is recommended to advance the development of some of these instruments and to acquire an improved understanding of liquid movement in landfills by application of the most promising techniques in the field.     

Use of inert C&D materials for seawall foundation: quality control measures

The technical viability of using inert construction and demolition (C&D) materials for the construction of seawall and breakwater foundations has been established by laboratory testing of the materials, numerical analysis of foundation stability, and a pilot field-scale engineering performance evaluation. However, quality control measures are still required so that only suitable materials are used for seawall and breakwater foundation construction. The development of different quality control measures for different site conditions is presented in this paper. The rationale, practicality, and implementation of these quality control measures are also discussed.     

Pilot installation for the thermo-chemical characterisation of solid wastes

The increasing production and the large variety of wastes require operators of thermal treatment units to continuously adapt the installations or the functioning parameters to the different physical and chemical properties of the wastes. Usually, the treated waste is encountered in the form of heterogeneous mixtures. The classical tests such as thermogravimetry and calorimetric bomb operate component by component, separately. In addition to this, they can analyse only small quantities of waste at a time (a few grams). These common tests are necessary but insufficient in the global waste analysis in the view further thermal treatment. This paper presents an experimental installation, which was designed and built at the CNRS Science Division, Department of Industrial Methods, Compiègne University of Technology, France. It allows the determination of waste thermal and chemical properties by means of thermal treatment. Also, it is capable of continuously analysing significant quantities of waste (up to 50kg/h) as compared to the classical tests and it can work under various conditions: The installation reproduces the process conditions from incinerators or pyrolysis reactors. It also provides complete information on the kinetics of the waste thermal degradation and on the pollutant emissions. Using different mixtures of components present in the municipal solid waste and also in the reconstituted MSW samples, we defined a series of criteria for characterising waste behaviour during the stages of the main treatment process such as: feeding, devolatilisation/oxidation, advancement, solid residue evacuation, and pollutants emission.     

Leachate recirculation effects on waste degradation: study on columns

The purpose of this study is to determine the impact of leachate recirculation on the degradation of municipal solid wastes (bioreactor concept). The study was carried out using columns containing approximately 50 kg of waste, in order to follow waste degradation over a limited time. Three types of waste were studied: fresh waste of standard composition, fresh waste of fermentable composition and some 8-yr-old waste extracted from a site in France. Measurement of the global parameters, such as chemical oxygen demand (COD), volatile acidity, alkalinity, leachate conductivity, methane potential of the wastes and biogas production monitoring (volume of CO2 and CH4 produced), were carried out. The quantity of oxydizable matter and biogas production was increased by the leachate recirculation, and the duration of the first degradation phases was reduced in all cases. Chloride, ammonium and organic pollution accumulation was observed according to the duration of recirculation. After 400 days of degradation, waste stabilization seemed to be reached for all of the recirculated columns (COD<300 mg/L O2, and methane potential reached).     

Biodegradability and ecotoxicity of amine oxide based surfactants

The aerobic and anaerobic biodegradability as well as the aquatic toxicity of two fatty amine oxides and one fatty amido amine oxide were investigated. Aerobic biodegradation was evaluated using the CO(2) headspace test (ISO 14593) and biodegradation under anaerobic conditions was assessed employing a standardised batch test. The three amine oxide based surfactants tested were readily biodegradable under aerobic conditions but only the alkyl amido amine oxide was found to be easily biodegradable under anaerobic conditions. Toxicity to Photobacterium phosphoreum and Daphnia magna was evaluated. Bacteria (EC(50) from 0.11 to 11 mg l(-1)) proved to be more sensitive to the toxic effects of the amine oxide based surfactants than crustacea (IC(50) from 6.8 to 45 mg l(-1)). The fatty amido amine oxide showed the lowest aquatic toxicity.     

Heavy metals in untreated/treated urban effluent and sludge from a biological wastewater treatment plant

Background, Aim and Scope

The presence of heavy metals in wastewater is one of the main causes of water and soil pollution. The aim of the present study was to investigate the removal of Cd, Cu, Pb, Hg, Mn, Cr and Zn in urban effluent by a biological wastewater treatment, as well as to quantify the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn in dewatering sludge from the Biological Wastewater Treatment Plant to Ribeirão Preto (RP-BWTP), Brazil.

Materials and Methods

Concentrations of Cd, Cr, Cu, Mn and Pb in wastewater and those of Ni in sludge were determined by atomic absorption spectrophotometry with graphite furnace atomization. Mercury concentrations in wastewater were measured by hydride generation atomic spectrophotometry, and Zn levels were determined by atomic absorption spectrophotometry using acetylene flame. In sludge, the levels of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Sn, Tl, V and Zn were determined by inductively coupled plasma-mass spectrometry.

Results

The percentages of removal efficiency (RE) were the following: Hg 61.5%, Cd 60.0%, Zn 44.9%, Cu 44.2%, PB 39.7%, Cr 16,5% and Mn 10.4%. In turn, the mean concentrations (mg/kg) of metals in dewatering sludge followed this increasing order: Tl (<0.03), Hg (0.31), Be (0.43), As (1.14), Cd (1.34), V (59.2), Pb (132.1), Sn (166.1), Cr (195.0), Mn (208.1), Ni (239.4), Cu (391.7), Zn (864.4) and Fe (20537).

Discussion

The relationship between metal levels in untreated wastewater, as well as the removal efficiency are in agreement with previous data from various investigators, It is important to note that metal removal efficiency is not only affected by metal ion species and concentration, but also by other conditions such as operating parameters, physical, chemical, and biological factors.

Conclusions

Metal values recorded for treated wastewater and sludge were within the maximum permitted levels established by the Environmental Sanitation Company (CETESB), São Paulo, Brazil.

Recommendations

There is an urgent need for the authorities who are responsible for legislation on sludge uses in agriculture of establishing safety levels for As, Be, Hg, Sn, Tl and V.

Perspectives

According to the current metal levels, RP-BWTP sludge might be used for agriculture purposes. However, for an environmentally safe use of sewage sludge, further studies including systematic monitoring are recommended. Annual metal concentrations and predicted variations of those elements in the sludge should be monitored.

     

A batch study on the bio-fixation of carbon dioxide in the absorbed solution from a chemical wet scrubber by hot spring and marine algae

Carbon dioxide mass transfer is a key factor in cultivating micro-algae except for the light limitation of photosynthesis. It is a novel idea to enhance mass transfer with the cyclic procedure of absorbing CO(2) with a high performance alkaline abosorber such as a packed tower and regenerating the alkaline solution with algal photosynthesis. Hence, the algae with high affinity for alkaline condition must be purified. In this study, a hot spring alga (HSA) was purified from an alkaline hot spring (pH 9.3, 62 degrees C) in Taiwan and grows well over pH 11.5 and 50 degrees C. For performance of HSA, CO(2) removal efficiencies in the packed tower increase about 5-fold in a suitable growth condition compared to that without adding any potassium hydroxide. But ammonia solution was not a good choice for this system with regard to carbon dioxide removal efficiency because of its toxicity on HSA. In addition, HSA also exhibits a high growth rate under the controlled pHs from 7 to 11. Besides, a well mass balance of carbon and nitrogen made sure that less other byproducts formed in the procedure of carboxylation. For analysis of some metals in HSA, such as Mg, Mn, Fe, Zn, related to the photosynthesis increased by a rising cultivated pH and revealed that those metals might be accumulated under alkaline conditions but the growth rate was still limited by the ratio of bicarbonate (useful carbon source) and carbonate. Meanwhile, Nannochlopsis oculta (NAO) was also tested under different additional carbon sources. The results revealed that solutions of sodium/potassium carbonate are better carbon sources than ammonia carbonate/bicarbonate for the growth of NAO. However, pH 9.6 of growth limitation based on sodium was lower than one of HSA. The integrated system is, therefore, more feasible to treat CO(2) in the flue gases using the algae with higher alkaline affinity such as HSA in small volume bioreactors.