Coagulation for treatment of swine slaughterhouse wastewater

In this study, wastewater taken from the Nam Phong swine slaughterhouse, Ho Chi Minh City, was used to evaluate the treatment efficiency of common coagulants, including Alum (Aluminum Sulfate - Al2(SO4)3.18H2O), Poly-Aluminum Chloride (PAC), and Ferrous Sulfate (FeSO4.7H2O), using a jar-test system. The experiments were conducted using the one-factor-at-a-time method to examine three variables which are pH, stirring speed, and coagulant dosage. The results showed that both Alum and PAC perform over 90% removal of colour, turbidity, COD, and total phosphorus (TP) from slaughterhouse wastewater at pH 7 with a stirring speed of 75 revolutions per minute (RPM) and average coagulant dosages of 450 mg/L for Alum and 550 mg/L for PAC. Meanwhile, under the appropriate conditions of pH equal to 10 and 75 RPM with a chemical dosage of 350 mg/L, COD and TP removal efficiencies by Ferrous Sulfate exceed 87%, but those of turbidity and colour only reach 25%. This finding could be a promising coagulation method as a pre-treatment for the swine slaughterhouse wastewater

Removal of inorganic nutrient and organic carbon from wastewater of Binh Dien market using the green alga Chlorella sp.

Traditional markets play a major role in socio-economics and constitutes a significant aspect of Vietnamese culture. However, wastewater streams discharged from the markets are generally characterized by a lot of inorganic nutrients and organic substances originated from fresh food processing units. They could lead to serious water contamination if discharged without proper treatment. This study applied microalgae Chlorella sp. for eliminating inorganic nutrients (NO3--N, NH4+-N and PO43--P) and organic carbon (Chemical oxygen demand-COD) from wastewater of the Binh Dien market. The removal efficiencies reached for NH4+-N > 86%, for NO3--N > 72%, and for PO43--P > 69%, respectively, at algal density of 49 x 104 cell mL-1, and for COD > 96% at algal density of 35 x 104 cell mL-1 after five cultivating days. The effluence satisfied the Vietnamese standard, column B, of the National technical regulation on industrial wastewater (QCVN 40:2011/BTNMT). The results demonstrated that the culture system composed of green algal Chlorella sp. could be a potential candidate for the removal of nutrients and organic carbon by a wastewater treatment process from the Binh Dien market

Purification and characterization of novel fibrinolytic proteases as potential antithrombotic agents from earthworm Perionyx excavatus

Six protease fractions, namely FI, FII, FIII-1, FIII-2, FIII-3 and FIV, were isolated from Perionyx excavatus earthworm biomass by acetone precipitation, followed by serial chromatography using anion exchange, hydrophobic interaction and size exclusion chromatography. All fractions exhibited strong hydrolytic activity towards casein. The activity of six fractions towards fibrin, determined by fibrin plate assay, ranged from 44 to 831 plasmin unit.mg-1 and ranked as FIII-3 > FIII-2 > FI > FIII-1 > FIV > FII. Casein degradation was optimal at pH 7 and 11, and at 45-60°C. All fractions were considerably stable at high temperature and wide pH range. They were completely inhibited by phenylmethylsulfonyl fluoride (PMSF). The molecular weights (MW) and isoelectric points (pI) determined by 2D-electrophoresis were 27.5-34.5 kDa, and 4.3-5.2, respectively. Tandem mass spectrometry (MS) analysis was used to deduce the amino acid sequences of some peptides from FIII-1 and FIII-2. The sequences shared 16.9% and 13.2% similarity, respectively, with the fibrinolytic enzymes from two related earthworm species, Lumbricus rubellus and Eisenia fetida. The P. excavatus proteases were classified as serine proteases. They could perform rapid hydrolysis on both coagulated fibrous fibrin and soluble fibrinogen monomers without the presence of activators such as tPA or urokinase

Optical Properties of Silicon Nanoparticles Prepared by Laser Ablation Method in Various Media

Bright photoluminescent silicon nanoparticles were successfully fabricated from porous silicon target in air and n-hexane using 532 nm line of YAG:Nd pulsed laser. The whole procedure was carried out at room temperature, in atmosphere. The morphology and composition of as-synthesized nanoparticles were characterized by SEM and EDS measurements. Their optical properties were investigated. The PL peak position of the as-synthesized Si nanoparticle ablated in air is slightly blue-shifted in comparison with those ablated in n-hexane, while it was almost no change of peak position of Si nanoparticles fabricated from p-Si in hexane and original p-Si wafer target. In contrast to PL intensity quenching of original p-Si sample and particles produced in air, those produced in n-hexane solvent exhibited an enhancement. The presence of dangling bonds or energy transfer from excited Si particles to oxygen molecules on the surface can be the cause of the quenching effect

THE AMOUNT AND SPECIATION OF TRACE ELEMENTS TRANSPORTED FROM RICE FIELD TO CANAL DURING A FLOODING EVENT

Trace element pollution of soils, sediments and surface water can pose a risk for the local population and the environment of Vietnam. Rice fields can be affected by storm events, which cause the release of trace elements into surface water and transport them into drinking wells. The aim of this study was to investigate if dissolved and suspended As, Pb and Zn concentrations in surface water of a paddy rice fields and an irrigation canals increased during a flooding event and exceed the Vietnamese Surface Water Quality Standards and WHO Guidelines for Drinking-water Quality. The study site is a rice field area in the Thanh Hoa province in Central Vietnam, which experiences an average of 2.4 storms every year causing overflow of streams and low-order canals. Concentrations of As increased during the flooding event with dissolved As being the prevailing fraction, which followed a late flush behavior. Lead showed no significant difference in concentration over time. Zn concentrations only increased significantly in the canal upstream the field in the morning of the first day. Suspended Zn dominated at that time, following the first flush behavior of TSS concentrations. Concentrations of As, Pb and Zn did not exceed the Vietnamese Surface Water Quality Standards or WHO Guidelines for Drinking-water Quality at any time and they are therefore of no concern for the health of the local populatio

Actionability of Climate Services in Southeast Asia: Findings from ACIS baseline surveys in Vietnam, Lao PDR and Cambodia

The baseline study under the project, “Agro-Climate Information Services for women and ethnic minority (ACIS) farmers in Southeast Asia,” strongly suggests that climate services must better suit farmers’ needs of climate information. In this Info note, the actionability of climate services can be improved by looking at the following factors: availability, accessibility, timeliness, understandability, and usefulness. Based on these factors, the study revealed that climate services are available in all countries covered by the ACIS project. However, issues on accessibility surfaced in the conduct of the study. Ethnic minority women are in the risk of experiencing particular marginalization, in particular due to language and extensionists more often meet men. Aside from accessibility issues, the study found that meteorologists and extension officers lack the necessary skills to package climate services in a more understandable manner for farmers

Evaluation of Xpert MTB/RIF and MODS assay for the diagnosis of pediatric tuberculosis

BACKGROUND: Tuberculosis (TB) in children is rarely confirmed due to the lack of effective diagnostic tools; only 10 to 15% of pediatric TB is smear positive due to paucibacillary samples and the difficulty of obtaining high-quality specimens from children. We evaluate here the accuracy of Xpert MTB/RIF in comparison with the Micoroscopic observation drug susceptibility (MODS) assay for diagnosis of TB in children using samples stored during a previously reported evaluation of the MODS assay. METHODS: Ninety-six eligible children presenting with suspected TB were recruited consecutively at Pham Ngoc Thach Hospital in Ho Chi Minh City Viet Nam between May to December 2008 and tested by Ziehl-Neelsen smear, MODS and Mycobacterial growth Indicator (MGIT, Becton Dickinson) culture. All samples sent by the treating clinician for testing were included in the analysis. An aliquot of processed sample deposit was stored at −20°C and tested in the present study by Xpert MTB/RIF test. 183 samples from 73 children were available for analysis by Xpert. Accuracy measures of MODS and Xpert were summarized. RESULTS: The sensitivity (%) in detecting children with a clinical diagnosis of TB for smear, MODS and Xpert were 37.9 [95% CI 25.5; 51.6], 51.7 [38.2; 65.0] and 50.0 [36.6; 63.4], respectively (per patient analysis). Xpert was significantly more sensitive than smear (P=0.046). Testing of additional samples did not increase case detection for MODS while testing of a second sputum sample by Xpert detected only two additional cases. The positive and negative predictive values (%) of Xpert were 100.0 [88.0; 100.0] and 34.1 [20.5; 49.9], respectively, while those of MODS were 96.8 [83.3; 99.9] and 33.3 [19.6; 49.5]. CONCLUSION: MODS culture and Xpert MTB/RIF test have similar sensitivities for the detection of pediatric TB. Xpert MTB RIF is able to detect tuberculosis and rifampicin resistance within two hours. MODS allows isolation of cultures for further drug susceptibility testing but requires approximately one week to become positive. Testing of multiple samples by xpert detected only two additional cases and the benefits must be considered against costs in each setting. Further research is required to evaluate the optimal integration of Xpert into pediatric testing algorithms

Sensitive Organophosphorus and Carbamate Pesticides Biosensor Based on Acetylcholinesterase and CdZnSe/ZnS Ternary Alloy Quantum Dots

This report presents the results of ternary alloy quantum dots (TQDs) manufacturing and its superior optical properties to fabricate the biosensor for pesticide detection. The explanation for the changes in PL intensity based on the change of electronic charges that alters the pH value of the surrounding environment, and the types of interaction on the surface of CdZnSe/ZnS TQDs were discussed. We show the decomposition process of the indicator (ATCh) with the catalysis from acetylcholinesterase enzyme (AChE) that inhibited by organophosphorus and carbamate pesticides including Trichlorfon (TF), Cypermethrin (CH), Abamectin (AT), and Carbosulfan (CS) with concentrations from 0.05 ppm to 10 ppm

COPPER HEXACYANOFERRATE (II): SYNTHESIS, CHARACTERIZATION, AND CESIUM, STRONTIUM ADSORBENT APPLICATION

Low-cost nanoscale copper hexacyanoferrate (CuHF), a good selective adsorbent for cesium (Cs+) removal, was prepared using the chemical co-precipitation method. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and high-resolution transmission electron microscopy (HR-TEM) were conducted to determine the CuHF morphology. Copper hexacyanoferrate, Cu13[Fe(CN)6]14.(2K).10H2O, has a cubic structure (space group F-43m) in the range of 10-30 nm and a Brunauer-Emmett-Teller (BET) surface area of 462.42 m2/g. The removal of Cs+ and Sr2+ is dependent on pH; the maximum adsorption capacity (qmax) of CuHF is achieved at a pH = 6. From the Langmuir model, qmax = 143.95 mg/g for Cs+ and 79.26 mg/g for Sr2+, respectively. At high concentrations, Na+, Ca2+, and K+ ions have very little effect on Cs+ removal, and Na+ and K+ ions have a higher affinity for removing Sr2+ than Ca2+ at all concentrations. CuHF has a high affinity for alkaline cations in the order: Cs+ > K+ > Na+ > Ca2+ > Sr2+, as proposed and discussed