Effects of Hypoxia on the Distribution of Calanoid Copepod Eggs in the Seabed Sediments of the Eutrophic Masan Bay, Korea

In this study, we investigate the distribution of calanoid copepod eggs in the sediments of Masan Bay (South Sea, Korea), in which hypoxic conditions occur every summer. In August (2011), hypoxia was observed at all stations, while normoxia was observed in April (2012). The pH and hydrogen sulphide concentration at the sediment-water interface in the inner bay during August were 7.7 and >20 mol L−1, respectively, and there was no significant difference between the stations in April. The abundance of eggs in the sediment ranged from 0.69 to 1.49 × 106 eggs m−2 in August, and from 0.59 to 1.08 × 106 eggs m−2 in April. Notably, the proportion of abnormal eggs was high (a maximum of 77.1%) in August, and a uniform distribution of normal eggs (>80%) was observed in April. A generation of abnormal eggs hatched with deformed nauplii in Masan Bay during the summer, and a failure to hatch was likely due to the high H2S concentration and low pH caused by hypoxia. In this paper, we discuss the effects of hypoxia and seabed environments on the hatching success of calanoid copepod eggs.

Examination of hydrogen cross-feeders using a colonic microbiota model

Background Hydrogen cross-feeding microbes form a functionally important subset of the human colonic microbiota. The three major hydrogenotrophic functional groups of the colon: sulphate-reducing bacteria (SRB), methanogens and reductive acetogens, have been linked to wide ranging impacts on host physiology, health and wellbeing. Results An existing mathematical model for microbial community growth and metabolism was combined with models for each of the three hydrogenotrophic functional groups. The model was further developed for application to the colonic environment via inclusion of responsive pH, host metabolite absorption and the inclusion of host mucins. Predictions of the model, using two existing metabolic parameter sets, were compared to experimental faecal culture datasets. Model accuracy varied between experiments and measured variables and was most successful in predicting the growth of high relative abundance functional groups, such as the Bacteroides, and short chain fatty acid (SCFA) production. Two versions of the colonic model were developed: one representing the colon with sequential compartments and one utilising a continuous spatial representation. When applied to the colonic environment, the model predicted pH dynamics within the ranges measured in vivo and SCFA ratios comparable to those in the literature. The continuous version of the model simulated relative abundances of microbial functional groups comparable to measured values, but predictions were sensitive to the metabolic parameter values used for each functional group. Sulphate availability was found to strongly influence hydrogenotroph activity in the continuous version of the model, correlating positively with SRB and sulphide concentration and negatively with methanogen concentration, but had no effect in the compartmentalised model version. Conclusions Although the model predictions compared well to only some experimental measurements, the important features of the colon environment included make it a novel and useful contribution to modelling the colonic microbiota.

Development of Numerical Eulerian-Eulerian Model for Computational Analysis of Potential in Chemical Process Intensification from Trickle Bed Reactors

The computational fluid dynamics techniques keep a paramount role by evaluating a reactor performance. The transitory performance of a Trickle bed reactor is readily monitored from its three phase’s flow conditions. This research review study corresponds towards the formation of boundaries in this Trickle bed reactors system to designate its comprehensive methodology with an optimized solution. The main paramount significance of computational fluid dynamics techniques is to observe the validity and an effective significance of the experimental result. The catalyst bed is modelled with the help of dynamic and steady state models by introducing mass and energy conservation equations. The Eulerian-Eulerian multiphase modelling technique is designed for hydro-desulfurization (HDS) and hydro-dearomatization (HDA) chemical process change from interactive momentum models. The effect in bed porosity on the HDS reaction process is observed from interactive mass transfer with solid bed condition in Trickle bed reactor. The congregated results from computational fluid dynamics codes show that wetting efficiency increases with increase in both hydrogen sulphide concentration and HDS conversion. The conversion of HDS reaction decreases with increase in hydrogen disulphide (H2S) concentration at both partially wetted and wetted bed conditions. On the other hand, there is small decrease in HDS conversion from 72% to 63.75% at H2S volumetric concentration of 0 to 8%. These observations also indicate that computational fluid dynamics provides random accessibility of liquid flow in Trickle bed reactor. There results also reveal that there is periodic variation in saturated liquid phase. The regions which are close to its wall are less irrigated. These characteristics can be changed and have effect on the reactor performance. Hence, the present review study presents the unprecedented results with high accuracy.

Treatment of hide liming wastewater by carbon dioxide

Results of the investigation of hide liming process wastewater treatment by carbon dioxide are presented in a paper. Comparison of the wastewater characteristics before and after the treatment by carbon dioxide was carried out. It was attempted to regenerate sodium sulphide using three different solutions: 10% solution of sodium carbonate and 5% or 10% solution of sodium hydroxide. The kinetic of sodium sulphide concentration, general alkalinity and pH was established. The solutions with the regenerated sodium sulphide were explored for unhairing of hide. The solution of 10% sodium hydroxide with regenerated sulphides was the mostly suitable for this aim. The properties of unhaired pelt were determined and assessed.

Sulphide formation in sewage pipes and influence of H2S to aerobic activated sludge microorganisms

The object of this work is to research the sulphide formation process in pressure pipesand how the sulphur rich wastewater influences treatment process in Kohtla-Jiirvewastewater treatment plant (WWTP),In this work the ISO 8192 standard test has been used to estimate the inhibition of oxygendemand of activated sludge microorganisms in different sulphide concentrations and pHvalues, Two wastewaters has been investigated - leachate from coke- and ash hills andwastewater from inflow ofKohtla-Jii.rve WWTP,The leachate from coke- and ash hills, rich of sulphates and sulphides, with high pHvalues from l O+ 12, did not cause significant inhibition of oxygen demand of activatedsludge microorganisms, After the leachate has been mixed with other sulphate andsulphide rich wastewaters with lower pH values, the mixed wastewater inhibits theoxygen demand of microorganisms in activated sludge process. One of the reasons is theincreased sulphide concentration but the essential factor is also decreasing of pH.

PENGARUH PEMBERIAN ENZIM DENGAN KONSENTRASI BERBEDA PADA PAKAN IKAN NILA (Oreochromis niloticus) TERHADAP KONSENTRASI AMONIAK, NITRIT, DAN SULFIDA DALAM MEDIA PEMELIHARAAN (The Influence of Enzime Provision with Different Concentration of Enzimes on Tilapia Fish Feed (Oreochromis niloticus) Towards The Concentration of Ammonia, Nitrite, and Sulfide in Media Maintenance)

Kegiatan budidaya pada setiap prosesnya menghasilkan limbah yang dihasilkan dari sisa-sisa pakan dan kotoran yang berasal dari ikan budidaya, terutama budidaya Ikan Nila yang merupakan salah satu jenis ikan tawar yang sudah di budidaya secara komersial oleh masyarakat indonesia. Penelitian dilaksanakan pada Mei-Juni 2017 di Laboratorium Pengelolaan Sumberdaya Ikan dan Lingkungan, Departemen Sumberdaya Akuatik, Fakultas Perikanan dan Ilmu Kelautan, Universitas Diponegoro. Pada penelitian ini ditambahkan enzim pada pakan ikan, suatu enzim yang mengandung protease, lipase, amilase, pepsin, tripsin, dan kemotripsin dalam dosis yang sudah ditentukan untuk memaksimalkan proses pencernaan. Ikan Nila yang digunakan berukuran 7-9 cm dipelihara di dalam akuarium dengan kapasitas 2 ekor Ikan Nila dalam 1 akuarium dengan volume air 9 l. Tujuan penelitian untuk mengetahui konsentrasi amoniak, nitrit, dan sulfida (H2S) dan membandingkan pengaruh pemberian enzim dengan konsentrasi yang berbeda didalam pakan terhadap konsentrasi amoniak, nitrit, dan sulfida (H2S). Metode yang digunakan adalah metode eksperimental skala laboratorium. Desain penelitian berdasarkan rancangan acak lengkap (RAL), dengan menggunakan lima perlakuan yaitu dengan perbedaan konsentrasi enzim. Setiap perlakuan dilakukan 3x pengulangan. Analisis data menggunakan uji two way anova. Hasil penelitian menunjukkan bahwa pemberian enzim dengan konsentrasi berbeda tidak berpengaruh nyata, lama waktu pemeliharaan berpengaruh nyata terhadap konsentrasi amoniak, dan sulfida, kombinasi dari keduanya tidak berpengaruh nyata terhadap konsentrasi amoniak, nitrit, dan sulfida. Cultivation activities in each process produce waste generated from the remnants of feed and feces from the fish cultivated, especially the cultivation of tilapia which is one type of fresh bonds that have been cultivated commercially by the people of Indonesian. The research was conducted in May-June 2017 at the Fish and Environmental Resource Management Laboratory, Aquatic Resources Department, Fisheries and Marine Science Faculty, Diponegoro University. The materials on this research are combining the fish feed with an enzime which contains protease, lipase, amylase, pepsin, trypsin, and chemotrypsin in prescribed doses to maximised the digestion process. Tilapia as research object has length of 7 to 9 cm and its kept in an aquarium with capacity (water volumes) of 9 ls which contains of 2 tilapias. The purposes of this research are to know the concentration of ammonia, nitrite and sulfide (H 2 S) in and to compare the effect of the enzyme provision with different concentration in fish feed with the concentration of ammonia, nitrite and sulfide (H 2 S). This research used laboratory-scale experimental method. The study design was based on Complete Randomized Design (RAL), using five treatments with different enzyme concentrations. Each treatments was done by three repetitions. The data was analysed using two-way ANOVA test. The results showed that enzyme with different concentration had no significant effect, maintenance time had significant effect on ammonia concentration, and sulfide, the combination of both did not significantly affect the ammonia, nitrite and sulphide concentration.

Treatment of discontinuous emission of sewage sludge odours by a full scale biotrickling filter with an activated carbon polishing unit

A SULPHUSTM biotrickling filter (BTF) and an ACTUSTM polishing activated carbon filter (ACF) were used at a wastewater treatment plant to treat 2,432 m3·h−1 of air extracted from sewage sludge processes. The project is part of Thames Water's strategy to reduce customer odour impact and, in this case, is designed to achieve a maximum discharge concentration of 1,000 ouE·m−3. The odour and hydrogen sulphide concentration in the input air was more influenced by the operation of the sludge holding tank mixers than by ambient temperature. Phosphorus was found to be limiting the performance of the BTF during peak conditions, hence requiring additional nutrient supply. Olfactometry and pollutant measurements demonstrated that during the high rate of change of intermittent odour concentrations the ACF was required to reach compliant stack values. The two stage unit outperformed design criteria, with 139 ouE·m−3 measured after 11 months of operation. At peak conditions and even at very low temperatures, the nutrient addition considerably increased the performance of the BTF, extending the time before activated carbon replacement over the one year design time. During baseline operation, the BTF achieved values between 266–1,647 ouE·m−3 even during a 6 day irrigation failure of the biofilm.

Investigations on Corrosion Behaviors of Super-Strength Sucker Rod Steel in High SO42- Environment

In some sour reservoirs and tertiary oil recovery blocks, SO42- in solution can cause the corrosion and corrosion fatigue of the sucker rods. In this paper, the corrosion behaviors of super-strength sucker rod FG20 (16Mn2SiCrMoVTiA) steel in the well fluid are investigated by electrochemical measurements, and electron probe micro-analyzer (EPMA) analysis. The results show that FG20 steel has a favorable corrosion resistance in neural solutions. When the hydrogen ion content increases, the hydrolysis of SO42- greatly accelerates the corrosion of FG20 steel. The energy dispersive X-ray(EDX)results demonstrate that the corrosion process of FG20 steel in neural well liquid is an oxygen concentration process, and the protective FeCO3 and Fe2O3 on the surface of the samples can prevent further corrosion. With the increase of the acidity in the well liquid, the corrosion process converts into a sulphide concentration process, and the sloppy FeS and mackinawite film cannot provide effective protection for the specimens, resulting in the increase of corrosion rate.