Study of non-revenue water status and enforcement measures to reduce water loss: case study in villages of Kermanshah Province of Iran

In this study, the volume and the cash value of water loss, and reduction of water loss as a result of enforcement action during 2011–2013 in the drinking water network of villages in Kermanshah Province, Iran, have been investigated. Date collected by referring to the different parts of rural water and waste water company of Kermanshah Province and checklist were completed. The study showed the volume of produced water and sold water has increased and the water loss percentage has decreased. High cost of water production compared to revenue of sold water and water loss resulted in significant detriments in terms of the water production costs. Water loss level decreased from 33% to 30% as result of measures taken to reduce water loss but, it is still 15% higher than the world average level. Also the reduction in number of water resources and increase in the number and volume of reservoirs indicates a lack of water and a growing need. As result of high water loss, waste of costs in the contrast of water production cost and also because physical water loss accounts for most of the water loss of villages, necessary measures can be effective in reducing loss and have economic justification.     

Biodegradation of phenol by Ralstonia eutropha in a Kissiris-immobilized cell bioreactor

This study examined the biodegradation of phenol by Ralstonia eutropha in a Kissiris-immobilized cell bioreactor (ICB), operated in a repeated batch recycling mode. The steady biodegradation rate of 23.7 mg/g/h, over a wide range of the initial phenol concentrations up to 1400 mg/L in the ICB, indicated an increased tolerance limit of the Kissiris-immobilized cells towards phenol. Both Haldane and Luong substrate inhibition models were used to describe biodegradation kinetic of free cells system. The Haldane equation gave the following values for the biokinetic parameters: micro(max) = 0.36 h(-1), Ks = 40.48 mg/L, and Ki = 181.9 mg/L. However, according to the Luong model, these parameters were micromax) = 0.23 h(-1), Ks = 24.8 mg/L, Sm = 1018 mg/L, and n = 1.3. By following appropriate operational conditions and use of the ICB, it was found to be possible to extend the efficiency of the highly porous structure of the siliceous mineral Kissiris in cell immobilization. This holds significant promise for pollutant biodegradation issues.     

Dimensional Stability and Water Uptake Properties of Cement-Bonded Wood Composites

This study was carried out to explore the possibility of making cement-bonded composite building products using eucalypt (Eucalyptus camaldulensis) and poplar (Populus deltoides). The experimental design consisted of three treatments—mixture of fibrous materials, cement and calcium chloride (CaCl₂) contents. Some physical properties, vis. water absorption (WA) and thickness swelling (TS), were investigated. The ratio of woodwool : cement was 40:60 and 60:40 by weight. Results showed that, water uptake increased with increasing woodwool content. In addition, boards fully made with poplar woodwools had superior properties compared to the eucalypt and mixed woodwools. The presence of eucalypt woodwools in mixture of fibrous materials typically resulted in increase in TS and WA. It is interesting to note that a dose of 5% of CaCl₂ by weight of cement can enhance the effect of cement. Application of Duncan’s Multiple Range Test for the mean values of the results showed that the effects of all variables and their interactions on the mechanical properties in terms of TS and WA were highly significant.     

Simple Arrhenius-type function accurately predicts dissolved oxygen saturation concentrations in aquatic systems

A sufficient supply of dissolved oxygen (DO) is vital for life in higher organisms. In aquatic systems, oxygen regulates respiratory metabolism, mediates biogeochemical cycles, and is an integral component of water quality. In this work, a simple predictive tool for dissolved oxygen saturation concentrations in aquatic systems as a function of chloride concentration and temperature using a novel Arrhenius-type asymptotic exponential function has been formulated. The proposed method predicts the amount of dissolved oxygen saturation concentrations for temperatures up to 50 °C and chloride concentrations up to 25 g/l. Estimations are found to be in excellent agreement with the reliable data in the literature with average absolute deviation being 3%. The tool developed in this study can be of immense practical value for the engineers and scientists to have a quick check on the oxygen saturation concentrations in aquatic systems at various conditions without opting for any experimental measurements. In particular, environmental science experts would find the proposed approach to be user-friendly with transparent calculations involving no complex expressions.     

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width $(r/\emph{w})$ . The experimental results indicated that the convex pattern with $r/\emph{w}=0.35$ produced minimum bed scouring depth at the center line whereas the concave pattern with $r/\emph{w}=0.23$ produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.     

Petroleum pollution in mangrove forests sediments from Qeshm Island and Khamir Port—Persian Gulf, Iran

The concentrations of total polycyclic aromatic hydrocarbons (?PAHs) and 22 individual PAH compounds in 42 surface sediments collected from the mangrove forest of Qeshm Island and Khamir Port (Persian Gulf) were analyzed. ?PAHs concentrations ranged from 259 to 5,376 ng?g^?1 dry weight with mean and median values of 1,585 and 1,146 ng?g^?1, respectively. The mangrove sediments had higher percentages of lower molecular weight PAHs and the PAH profiles were dominated by naphthalene. Ratio values of specific PAH compounds were calculated to evaluate the possible source of PAH contamination. This ratios suggesting that the mangrove sediments have a petrogenic input of PAHs. Sediment quality guidelines were conducted to assess the toxicity of PAH compounds. The levels of total PAHs at all of stations except one station, namely Q₆, were below the effects range low. Also, concentrations of naphthalene in some stations exceeded the effects range median.