TWO-STAGE DEGRADATION OF SOLID ORGANIC WASTE AND LIQUID FILTRATE

The accumulation of solid and liquid organic waste requires their treatment to develop energy biotechnologies and prevent environment pollution. Aim. The goal of the work was to study the efficiency of the purification of the filtrate from dissolved organic compounds by aerobic oxidation and methane fermentation. Methods. The standard methods were used to determine рН and redox potential (Eh), the gas composition, the content of short-chain fatty acids, the concentration of dissolved organic compounds counting to the total сarbon. The efficiency of two types of microbial metabolism for the degradation of soluble organic compounds of filtrate was compared. Results. The aerobic oxidation was established to provide 1.9 times more efficient removal of dissolved organic compounds, compared with the anaerobic methane fermentation. However, it provided CH4 yield 1 L/dm3 of filtrate (сarbon concentration — 1071 mg/L). The necessity to optimize the methods for purifying filtrate to increase the efficiency of the process was determined. Conclusions. The obtained results will be the basis to develop complex biotechnology providing not only the production of environmentally friendly energy H2 via the fermentation of solid food waste, but also the purification of filtrate to solve the ecological and energy (CH4 production) problem of society.

Toward a Microscopic Model of Light Absorbing Dissolved Organic Compounds in Aqueous Environments: Theoretical and Experimental Study

Water systems often contain complex macromolecular systems that absorb light. In marine environments, these light absorbing components are often at the air-water interface and can participate in the chemistry of...

Membrane Filtration Enhanced Hydrometallurgical Recovery Process of Indium from Waste LCD Panels

Insufficient recycling of a continuously increasing amount of liquid crystal display (LCD) waste leads to the waste of potentially recyclable materials, especially rare and critical indium. Moreover, landfilling of LCD waste increases the potential for environmental risk. This paper describes a recycling process combining membrane filtration unit processes to hydrometallurgical indium recovery process. The LCD panels were crushed and leached with 1 M H2SO4. 97.4% yields on average were obtained, and a novel finding was made about fast kinetics (2 min for the maximum indium yield). Ultrafiltration was used to remove the dissolved organic material from the leachate, which was concentrated with nanofiltration before liquid–liquid extraction for indium purification. The results showed that commercial polymeric membranes removed more than 90% (from over 3000 mg/L to under 200 mg/L) of the dissolved organic compounds, thus potentially significantly diminishing the detriments caused by these compounds in the liquid–liquid extraction step. The concentration of the leachate with nanofiltration enables the use of smaller processing equipment and to save chemicals in the further steps of the process. The indium content in the leachate was more than five times higher after nanofiltration than after leaching (126 mg/L vs. 677 mg/L). In liquid–liquid extraction, the phase separation took place in only 34 s with the membrane-treated leachate, while with the untreated leachate it remained incomplete even after three hours. The purity of indium was increased from 10 to 74%. From the obtained HCl solution, a 95.5% pure indium product with 69.3% yield was obtained by cementation. Graphical Abstract

Symmetrical Analysis of Low-Cost Filter Media and Their Efficiency in Treatment of Water

Separating is a compelling procedure in expelling particles from water because utilization of sand become nowadays is very challenging in filtration process. It is a necessity to find an alternative media which must satisfy the low cost, easy availability, high durable with less zone required and discharge of water. Many ponds are contaminated mostly in high level of turbidity. In this work it is identified the various synthetic filter media taken examined for the replacement sand. The high level of turbid water may contain slit, dissolved organic compounds, and other microscopic organisms. So, in this method all contaminants are removed. The filtration procedure was created to break down and filtration of lab scale arrangement was planned. The performance as concerns lab scale reactor was optimized by using HDPE (High Density Polyethylene) granules are easily available in all polymer industries are used as a filter media. A proportional study of natural filter media sand and synthetic filter media HDPE granules was undergone for investigation. This two-filter media were selected because of its locally available and two different size of media (sand 2.5 mm, HDPE 3.5 mm) were evaluated. Bentonite (20mg/l ≈ 120 NTU). Identified two parameters were influenced the filtration recital i.e. media depth, filtration velocity. The outcomes uncovered to evacuate turbidity in best conditions where start to be low filtration rate (10.62 l/m² min), extended media midst (240mm). The removal of turbidity in sand was 70% and in plastic media was 55%. Nevertheless, headloss was achieved in higher manner comparing to plastic media. The treated water used as agriculture purpose.

Osmotrophic glucose and leucine assimilation and its impact on EPA and DHA content in algae

The uptake of dissolved organic compounds, that is, osmotrophy, has been shown to be an efficient nutritional strategy for algae. However, this mode of nutrition may affect the biochemical composition, for example, the fatty acid (FA) contents, of algal cells. This study focused on the osmotrophic assimilation of glucose and leucine by selected seven algal strains belonging to chlorophytes, chrysophytes, cryptophytes, dinoflagellates and euglenoids. Our laboratory experiments with stable isotope labeling showed that osmotrophy occurred in four of the selected seven strains. However, only three of these produced long chain omega-3 FAs eicosapentaenoic acid (EPA; 20:5ω3) and docosahexaenoic acid (DHA; 22:6ω3). High glucose content (5 mg L−1) affected negatively on the total FAs of Mallomonas kalinae and the total omega-3 FAs of Cryptomonas sp. Further, glucose assimilation explained 35% (negative effect) and leucine assimilation 48% (positive effect) of the variation of EPA, DHA and the FAs related to their synthesis in Cryptomonas sp. Moderate glucose concentration (2 mg L−1) was found to enhance the growth of Cryptomonas ozolinii, whereas low leucine (20 µg L−1) enhanced the growth of M. kalinae. However, no systematic effect of osmotrophy on growth rates was detected. Our study shows that osmotrophic assimilation of algae is species and compound specific, and that the effects of the assimilated compounds on algal metabolism also varies depending on the species.

Serious interference of dissolved organic compounds in the laser induced fluorimetric determination of uranium in water: a selective & sensitive method for the laser induced fluorimetric determination of uranium in water

In this report, serious negative interference of Dissolved Organic Compounds (DOCs) in the laser/LED fluorimetric determination of uranium in natural and waste waters has been amply demonstrated.

Removal of Dissolved Organic Compounds and Contaminants from Wastewater of a Petroleum Refinery by Ion Exchange

The efficient removal of dissolved organic compounds (DOC) from wastewater has become a major environmental concern because of its high toxicity even at low concentrations. Therefore, a technique was needed to reduce these pollutants. Ion exchange technology (IE) was used with AmberliteTM IR120 Na, AmberliteTM IR96RF, and AmberliteTM IR402, firstly by using anion and mixed bed system, where the following variables are investigated for the process of adsorption: The height of the bed in column (8,10 and 14 cm), different concentrations of (DOC) content at constant flow rate. The use of an ion exchanger unit (continuous system) with three columns (cation, anion, and mixed bed) was studied. The effect of the following variables, such as a change in temperatures (23,30 and 40 Co) and the change in flow rate (2,4,6 L/min) was studied. The results showed that the adsorption capacity decreased with increasing the flow rate. The linear equation models of (Langmuir, Freundlich, Timken, and Dubinin-Radushkevich) were used. The results were analyzed using three known models for equilibrium and temperature constant. Graphically, the Langmuir model was the most consistent with the adsorption results because it has the highest adsorption capacity and the highest correlation value of R2 = 0.97. The ion exchange column dynamics were studied using models such as (Thomas model). The results showed that the experimental results were well correlated with the model equations. While the tests showed that the removal rate of pollutants was up to 90% for organic compounds.