Potential Carbon Thickness on Ammonia Content in Nile Tilapia (Oreochromis niloticus) Aquaponics System with Water Spinach (Ipomoea aquatica)

The application of aquaponics aquaculture is needed to improve water quality, especially the addition of filtration materials which act as absorbent planting mediums for ammonia nitrogen content in toxic water. The purpose of the current study was to determine the effect of the carbon thickness on ammonia levels in Nile tilapia in aquaponics systems with Water spinach. The study used an experimental method with a completely randomized design consisting of four treatments and five replications. The main parameter was ammonia level. Supporting parameters in this study included initial and final growth of Water spinach, fish survival rate, specific growth rate, and water quality which included temperature measurement, dissolved oxygen, and pH. Each treatment consisted of variations of carbon thicknesses at P0 (control), P1 (5 cm), P2 (7 cm), and P3 (9 cm). The results revealed that ammonia levels were significantly different at P1, P2, and P3 in the third and fourth weeks. Ammonia levels during the study decreased from 0.3969 ppm to 0.1741 ppm. The reported value of 7.2 was for acidity degree, 29.3°C for the temperature, 5.94 ppm for dissolved oxygen, 8.42 cm for the growth of Water spinach, 0.44% for the specific growth rate, and 90% for the survival rate. Carbon thickness caused a decrease in ammonia levels in Nile tilapia with aquaponics systems through the medium of Water spinach.

Combined NOx and NH3 Slip Reduction in a Stoker Boiler Equipped with the Hybrid SNCR + SCR System FJBS+

The application of secondary NOx control methods in medium to low-capacity furnaces is a relatively new topic on the energy market and thus requires further research. In this paper, the results of full-scale research of SNCR and hybrid SNCR + SCR methods applied into a 29 MWth solid fuel fired stoker boiler is presented. The tests were performed for a full range of boiler loads, from 33% (12 MWth) to 103% (30 MWth) of nominal load. A novel SNCR + SCR hybrid process was demonstrated based on an enhanced in-furnace SNCR installation coupled with TiO2-WO3-V2O5 catalyst, which provides extra NOx reduction and works as an excess NH3 “catcher” as well. The performance of a brand-new catalyst was evaluated in comparison to a recovered one. The emission of NOx was reduced below 180 mg NOx/Nm3 at 6% O2, with ammonia slip in flue gas below 10 mg/Nm3. Special attention was paid to the analysis of ammonia slip in combustion products: flue gas and fly ash. An innovative and cost-effective method of ammonia removal from fly ash was presented and tested. The main idea of this method is fly ash recirculation onto the grate. As a result, ammonia content in fly ash was reduced to a level below 6.1 mg/kg.

Effects of Preparation Conditions on the Efficiency of Visible-Light-Driven Hydrogen Generation Based on Cd0.25Zn0.75S Photocatalysts

Photocatalytic H2 production utilizing H2S, an industrial side-product, is regarded as an environmentally friendly process to produce clean energy through direct solar energy conversion. For this purpose, sulfide-based materials, such as photocatalysts, have been widely used due to their good solar response and high photocatalytic activity. In this work, a ZnS–CdS composite was studied, and special attention was dedicated to the influence of the preparation parameters on its H2 production activity. The ZnS–CdS composite, with an enhanced photoactivity for H2 production, was synthesized both from ammine complexes and, in a conventional way, directly from acetates at various pH values. Deviating from the traditional method, the photoactivity of ZnS–CdS prepared from ammine complexes was not affected by the pH. Besides, the hydrothermal treatment and the ammonia content strongly influenced the rate of H2 production in this system. DRS, TEM, SEM, XRD, and quantum yield measurements prove the dependence of the photoactivity of these catalysts on the structural and morphological properties determined by the preparation conditions. The promising photocatalytic efficiency achieved with the application of these ZnS–CdS catalysts, prepared without any metal deposition, encourages further investigations to enhance the rate of hydrogen generation by optimization of the reaction conditions for practical utilization.

Fish Farm Wastewater Treatment using Moringa oleifera Seed Powder as Natural Coagulant

In view of the huge amount of wastewater being generated from the aquaculture sector in Malaysia, Moringa oleifera seed powder was utilized as effective bio-coagulant to minimize the deterioration of fish farm wastewater quality. In this study, optimization of a coagulation-flocculation process was examined through response surface model toolkit established on a central composite design. A quadratic polynomial model was eventually selected to fit its turbidity removal response. The effect of four crucial parameters, namely pH, coagulant dosage, mixing time and settling time was optimized at pH 10, 400 mg/L coagulant dosage, 15 minutes mixing time and 10 minutes settling time for M. oleifera seed extract at a 47.11% turbidity removal efficiency. M. oleifera seed powder substantially removed (>30%) the concentration of total suspended solids, ammonia content, total volatile solids, and phosphate content as compared with the control group without any coagulant addition.

Cationic Lignin Polymers as Flocculant for Municipal Wastewater

The radical polymerization of acid-washed and unwashed softwood kraft lignin with [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC) was attempted to investigate the production of lignin-based flocculants for simulated wastewater. The incorporation of METAC onto lignin resulted in a cationic charge density (2.3–3.3 meq/g), increased water solubility (89–96% in neutral pH), and increased molecular weight (70,000–210,000 g/mol) of lignin. The lignin–METAC polymers generated from acid-washed lignin had higher molecular weights than those generated from unwashed lignin. The lignin–METAC polymers showed lower resistance to thermal decomposition than unmodified lignin due to the inclusion of PolyMETAC. The unmodified acid-washed lignin samples did not significantly affect the COD of the wastewater, while the unmodified unwashed lignin samples contributed to the COD, implying that unmodified lignin was not suitable for wastewater treatment. The flocculation of wastewater with lignin–METAC led to the chemical oxygen demand (COD) reduction of 17–23% and total organic carbon (TOC) drop of 51–60%. The lignin–METAC polymer with the highest molecular weight (produced from acid-washed lignin) reached the highest COD removal, while lignin–METAC polymer with the highest charge density (produced from unwashed lignin) reached the highest TOC removal. Focused beam reflectance measurement (FBRM) studies revealed that the lignin–METAC polymer produced from acid-washed lignin with a high molecular weight generated larger and more flocs in wastewater than the lignin–METAC polymer produced from unwashed lignin. The comparison of theoretical and experimental dosages required for neutralizing the charges of wastewater demonstrated that charge neutralization was the main flocculation mechanism, although a bridging mechanism was also involved for component removals from wastewater. The use of 1 mg/L of alum along with 65 mg/L lignin–METAC in a dual coagulation–flocculation system led to higher average phosphorous (42%) and COD (44%) removals than the singular flocculation system only using 65 mg/L of lignin–METAC (with phosphorous removals of 3.4% and COD removals of 18.7%). However, lignin–METAC flocculant slightly increased the ammonia–nitrogen content in both singular flocculation and dual coagulation–flocculation systems due to the residual ammonia content of lignin–METAC. The coagulation–flocculation system determined that the use of lignin–METAC (65 mg/L) could reduce the alum dosage significantly while maintaining a similar organic content reduction of 44% for wastewater.

Correlations between the Chemical, Microbiological Characteristics and Sensory Profile of Fungal Fermented Food

Fungal fermented foods are nutritious, environmentally friendly and sustainable protein sources. To develop fungal fermented food with acceptable sensory characteristics, it is important to assess factors that can affect the sensory characteristics of the product. The current study aimed to investigate the correlations between the chemical and microbiological characteristics and sensory characteristics of fungal fermented food. Soybeans were fermented using five local Indonesian strains of the genus Rhizopus sp. and one strain of industrial starter to mimic traditional Indonesian tempe. The chemical (amino acid and ammonia content), microbiological (lactic acid bacteria, proteolytic bacteria and yeast) and sensory characteristics of the fermented products were examined. The results showed that there is a correlation between the chemical properties, particularly glutamic acid and aspartic acid, and the overall liking of different types of tempe. In general, Rhizopus oligosporus-fermented products had better sensory characteristics than those fermented with Rhizopus oryzae and Rhizopus delemar. The sensory characteristics of the fermented products in this work made from isolates are comparable to those made with an industrial starter culture. In addition, taste and texture affect the overall liking of the product. The results of this study contribute to the development of acceptable sensory fungal fermented food and, in particular, the screening of potential starters.

Effects of the Invasive Tree Species Ailanthus altissima on the Floral Diversity and Soil Properties in the Pannonian Region

Tree-of-heaven (Ailanthus altissima) is one of the most dangerous and widespread invasive woody plant species in Europe. Despite the fact that A. altissima is in the focus of an increasing number of research projects, the impact of its mass spread on native vegetation, its diversity, and changes in soil quality are still incomplete. The current study addresses the effects of this invasive species on plant diversity and soil parameters simultaneously. The main objective of our research is to determine the impact of cover and mass of A. altissima on the diversity of each forest layer; the examined soil parameters and on other selected environmental variables. For botanical and pedological investigations we selected nine A. altissima-dominated sites in Central Europe, in the Pannonian Biogeographical Region. Based on our results, it can be stated that fully grown A. altissima-dominated stands can displace other taxa by their shading and allelopathy, thereby reducing canopy layer diversity. The increase in the species richness of the shrub layer had a positive correlation with the diversity of the floor layer and also with the humus and ammonia content of the soil. As the diversity of shrub layer and floor layer positively correlated with many soil parameters, the diverse vegetation of these layers can represent a potential opportunity for the regeneration of areas infected with A. altissima.

Efektifitas Pencampuran Poly Alumunium Chloride (PAC) dan Penyaringan Menggunakan Pasir Zeolit serta Arang Aktif dalam Mengurangi Kandungan Amonia Limbah Cair Industri Kulit

Liquid waste produced by the leather tanning industry is included in the list of hazardous and toxic wastes for the environment because it contains one of the chemicals, namely ammonia. The goal of this study was to minimize ammonia levels in tannery effluent by mixing Poly Aluminum Chloride (PAC) and filtering with activated charcoal and zeolite sand. This research method uses a control group and an experimental group with three repetitions for each type of reagent. After treatment, the ammonia content was tested using a Spectrophotometer. The data was examined using SPSS using the Regression Test to see if there was an effect of treatment on ammonia content reduction, and then the Kruskal Wallis Test in order of mean ranking to find the most effective type and level of treatment. The Mann Whitney test was then used to see how the relationship between the variables affected the results. The result was found that the PAC reagent level of 3.5 grams was the most effective in reducing ammonia to below the specified quality standard. Efforts to reduce ammonia are carried out to prevent the impact of ammonia gas which is harmful to human health. Abstrak: Limbah cair yang dihasilkan oleh industri penyamakan kulit termasuk dalam daftar limbah bahan berbahaya dan beracun bagi lingkungan karena mengandung salah satu bahan kimia yaitu ammonia. Penelitian ini bertujuan untuk meminimalkan kadar amonia pada limbah penyamakan kulit dengan mencampurkan Poly Aluminium Chloride (PAC) dan menyaring dengan arang aktif dan pasir zeolit. Metode penelitian ini menggunakan kelompok kontrol dan kelompok eksperimen dengan tiga kali pengulangan untuk setiap jenis reagen. Setelah perlakuan, kadar amonia diuji menggunakan Spektrofotometer. Hasil dianalisis menggunakan SPSS dengan Uji Regresi untuk mengetahui apakah ada pengaruh pemberian perlakuan terhadap penurunan kandungan amonia, kemudian untuk mengetahui jenis dan kadar yang paling efektif menggunakan Uji Kruskall Wallis pada urutan ranking mean. Kemudian dilakukan uji Mann Whitney untuk mengetahui pengaruh hubungan setiap variabel. Hasilnya ditemukan bahwa reagen PAC kadar 3,5 gram yang paling efektif mengurangi amonia hingga di bawah baku mutu yang ditentukan. Upaya mereduksi amonia dilakukan untuk mencegah dampak gas amonia yang membahayakan bagi kesehatan manusia.

Improper Diving Behavior Affects Physiological Responses of Acropora hyacinthus and Porites cylindrica

Human activities beyond ecosystem capacity have resulted in serious effects on corals worldwide. Nowadays, many studies have focused on the influence of diving activities on coral communities, while the knowledge of physiological changes under corresponding environmental stresses remains largely undetermined. In the study, we aimed to investigate the physiological effects of touching, ammonia nitrogen enrichment (5 μmol⋅L–1), and sediment cover (particle size of less than 0.3 mm), which simulated improper self-contained underwater breathing apparatus (SCUBA) diving behaviors, on Acropora hyacinthus and Porites cylindrica in Wuzhizhou Island, the South China Sea. For A. hyacinthus, continuous touching caused the tentacles to shrink and secrete mucus, which consumed energy and dissolved oxygen. The skeletal growth rate was decreased by 72% compared with the control group. There was a rapid decline of Fv/Fm and alpha under the dual impacts of high ammonia nitrogen and touching, while the Chl a concentration and tissue biomass were decreased by 36 and 28% compared with touching alone, respectively. High ammonia nitrogen and touching increased the concentrations of lipid and protein. Nevertheless, zooxanthellae density was increased by 23% to relieve the effects of a lower concentration of Chl a in a high nutrient environment. Constant touching and sediment cover in diving areas with elevated ammonia content affected the photosynthesis and respiration of corals, and a significant decrease was observed for lipid, zooxanthellae density, and Chl a concentration. Coral bleaching occurred on day 7. For P. cylindrica, the decreasing magnitude of Fv/Fm and alpha under different stresses in the subsequent phase was less compared with A. hyacinthus. The contents of carbohydrate and protein under continuous touching were decreased by 7 and 15% compared with the control group, respectively, causing negative growth. Under the dual influences of high ammonia nitrogen and continuous touching, all energy reserves were significantly lower. Repeated touching and sediment cover in diving areas containing high ammonia content increased the concentrations of lipid and protein compared with the touching and high nutrient treatment group likely because that Porites associated with C15 zooxanthella increased heterotrophic feeding to compensate for restricted symbiodiniaceae photosynthesis. Additionally, P. cylindrica produced mucus to aid the removal of sediment, so that corals didn’t obviously bleach during the experiment. Collectively, P. cylindrica was more resistant to diving activities than A. hyacinthus which only relies on photoautotrophy. To ensure the sustainable development of coral reef dive tourism, it is necessary to strengthen the supervision of diving behaviors, rotate the diving areas, and conduct regular assessments on the coral status.

Application of vermifiltration for sustainable management of septage

The current article presents an innovative technical solution for sustainable management of septage, via a vermifiltration system, in the Republic of Moldova. A technical description of the main components of a demonstration model that was implemented at a household level is presented. The results from the model show an 98.85% reduction of ammonia content, 49,21 % CODMn (an indicator of degradation of easily degradable organic substances) and 85,28% of CODCr (showing degradation of hardly degradable organic substances). Considering the fact that the concentration of ammonium in the effluent was considerable reduced, while that of nitrate nitrogen remained rather low, it was assumed that the activity of earthworms was rather limited, probable the microorganisms, interacting symbiotically and synergistically with earthworms not being well developed in the vermifilter bed. The study suggests that the vermifiltration technology can provide a sustainable wastewater management solution and its application can be promoted in certain settings such as schools and kindergartens in Moldova. However, good insulation should be considered to avoid the freezing problems during winter while the odor nuisance in the septic tank can be reduced by adding lactic acid bacteria can also be applied.