Fish Wastewater Research Articles

Optimization of CW-MFC System for Fish Wastewater Treatment by Response Surface Methodology

Optimization of CW-MFC System for Fish Wastewater Treatment by Response Surface Methodology

To Study the Need of Systemic Formwork for Waste Water Treatment at Fish Processing Plant' (A Review)

Waste water from angle preparation enterprises originates from several sources, including emptying angles, dressing, liquefying water from ice dissolution, washing equipment and utensils, treating with additional substances, and cleaning and disinfecting offices and spaces. Water is used not only to clean angles but also to wash blood, sludge, and offal from the surfaces of various handling equipment, utensils, floors, and sump pumps. The majority of computerized handling supplies come with a water shower framework that may clean hardware and remove offal. The emergence of these forms in tall water use also leads to the mixing of blood and offal in the wash water. Fish handling waste water is full of significant pollutants that are colloidal, soluble, and particulate. Features of waste water produced depend on the type of angle used for preparation, the preparation method, and the final object placed. When handling operations such as minor (angle washing or cleaning), mild (angle filet preparation), and severe (surimi planning), the degree of defilement can change. Fish waste water must have exceptionally high levels of nitrogen, fat, oil, and oil (Mist), as well as biochemical oxygen demand (BOD). In order to reduce shameful waste transfer in the environment, this extended show introduces angle waste management processors to the concepts of fishery waste categorization and the many types of treatment used. This topic includes many aspects of angle waste, separate management of fluid angle waste and strong waste using chemicals, Indore composting technique, and suitable transfer.

Amazon tropical fishes of commercial interest show human-cell contamination but no SARS-CoV-2 in a real-life scenario.

Amazonas was one of the most impacted Brazilian states by the COVID-19 pandemic. Mortality rates were high, and the health systems collapsed. It is important to identify possible intermediate reservoirs to avoid animal-to-human contamination. Several tropical fish are of commercial interest and are sold in large open-air markets in the region, representing a large economic and dietary importance. This study aimed to verify if fish species of commercial importance, aerosols, and fish wastewater in local open-air markets, at a major capital city in the western Brazilian Amazon, are contaminated by SARS-CoV-2. 488 fish, 50 aerosol, and 45 wastewater samples were analyzed for the presence of SARS-CoV-2. The samples were subjected to extraction using the BIOGENE Viral DNA/RNA Extraction kit, and the molecular diagnosis was tested for SARS-CoV-2 using the Bio-Manguinhos SARS-CoV-2 (EDx) Molecular Kit. It was not possible to detect the virus (Ct≤40, for Gene E) in these samples, however, in 181 samples of fish it was possible to detect the human RP gene (Ct≤35, for the RP Gene), indicating human contact. There was a high number of COVID-19 diagnoses in all city districts in which the samples were collected, showing that SARS-CoV-2 was circulating. This study indicates that fish of local commercial importance do not carry SARS-CoV-2 viral particles, despite circulation of SARS-CoV-2, and are not an important source of animal-to-human contamination. Despite these results, the human RP gene was found detectable in fish, air, and fish wastewater, showing that such places may carry human pathogens.

Greenhouse production of baby leaf vegetables using rainbow trout wastewater in a high-tech vertical decoupled aquaponic system

IntroductionAquaponics is an integrated food production system that links recirculating aquaculture with hydroponics, leading to higher water use efficiency than conventional food production systems while also saving on fertilizers. In the present study, baby lettuce and baby rocket plants cultivated hydroponically in a deep water culture system using wastewater from rainbow trout were evaluated as part of a vertical decoupled aquaponic system.Materials and methodsMore specifically, three different nutrient solutions were supplied: a) using fish wastewater only (designated as Fish); b) fish wastewater enriched with synthetic fertilizers (Mix); and c) a typical nutrient solution (Hoagland) as the control. Both lettuce and rocket plants were monitored in these nutrient solutions and in two different substrates, peat and perlite, as an organic and an inert substrate, respectively. The purpose of this study was to assess a vertical decoupled aquaponic system with regard to the resource use efficiency, such as water, land, and energy, while evaluating plant cultivation in the different treatments in terms of yield, growth, nitrate concentration on the leaf tissue, and foliar analysis. The photosynthetic rate and leaf color indices were also considered in the plant evaluation.ResultsThe Mix–Peat treatment was the most efficient growing combination in terms of land and water use efficiency, with approximately 7% better land use efficiency while using 38% less water and 10% less fertilizer than Hoagland–Peat. Moreover, lettuce plants had the highest yield in the Mix–Peat treatment, at 2,497 g m−2, which was approximately 6% higher than that of Hoagland–Peat while not being inferior in the quality measures. On the other hand, the yield of rocket was significantly higher in the Hoagland–Peat treatment, being 18% higher than that of Mix–Peat and 30% higher than that of Fish–Peat. Overall, the study confirmed that aquaponic systems could lead to higher water use efficiency and savings in fertilizers without undermining the yield and quality of lettuce, while the vertical arrangement developed within the scope of this study can increase the land useefficiency of the system.

Pengaruh pemberian air kotoran ikan dan biourin domba terhadap karakteristik fisiologi tanaman padi (Oryza sativa L.) Varietas inpari 32

One of the factors that influences plants physiological processes is the absorption of nutrients obtained from both organic and inorganic fertilizers. Some organic fertilizers that can be given are fish waste water and sheep urine fertilizer. The aim of this research is to obtain information regarding the effect of fish waste water and sheep biourine on the physiological characteristics of rice plants (Oryza sativa L.) such as leaf chlorophyll content, Net Assimilation Rate (NAR) and Crop Growth Rate (CGR). This research was conducted on Agricultural Extension Field, Majalaya District, Karawang Regency, from January to April 2022. This experiment used an experimental method with a split plot design (Split Plot Design) with 10 treatment combinations which were repeated 3 times. The main plots are fish waste water (A): A1 (fish waste water), and A2 (ordinary irrigation water). As subplots for Sheep Biourine (P): P0 (Control), P1 (Factory Biourine 100 ml/l), P2 (Sheep Biourine 100 ml/l), P3 (Sheep Biourine 150 ml/l) and P4 (Sheep Biourine 200 ml /l). The research results showed that there was no interaction between biourine fertilizer treatment and fish waste water on the physiology characteristics of the rice plants (Oryza sativa L.).

Effects of Salts and Other Contaminants on Ciprofloxacin Removal Efficiency of Green Synthesized Copper Nanoparticles.

Ciprofloxacin (CIP), a broad-spectrum fluoroquinolone antibiotic, is commonly used in aquaculture to prevent and treat bacterial infections in aquatic animals. For this reason, aquatic environments contain CIP and its derivatives, which lead to the development of drug-resistant bacteria. In the present study, copper nanoparticles were prepared using Garcinia mangostana extract (GME-CuNPs) as a reducing agent and evaluated for their CIP removal efficiency (CRE). The results demonstrate that within 20 min, GME-CuNPs at 25 mM possess a CRE of 92.02 ± 0.09% from CIP-containing aqueous media with pH 6-7. The CRE is influenced by both monovalent and divalent salts. A high salt concentration significantly reduces the CRE. Contaminants in fish wastewater can reduce the CRE, but phenolics, flavonoids, tannins, and ammonia do not affect the CRE. Our results reveal that the CRE is controlled by electrostatic attraction between the negatively charged GME-CuNPs and the cationic species of CIP. The CRE is reduced by wastewater with a pH higher than 8.0, in which the CIP molecules have a negative charge, resulting in a repulsive force due to the negative charge of GME-CuNPs. In fish wastewater with a pH lower than 7.0, GME-CuNPs show the potential to achieve a CRE above 80%. Therefore, pH adjustment to a range of 6-7 in fish wastewater before treatment is deemed imperative. It is concluded that the newly developed GME-CuNPs possess excellent activity in CIP elimination from actual fish wastewater samples. Our findings suggest that GME-CuNPs can be a promising tool to effectively eliminate antibiotics from the environment.

Growth and Yield Performance of Lactuca sativa L. Grown in Hydroponics using Fish Effluents and Inorganic Fertilizer

Aquaponics is an emerging sustainable food production technique where waste from fish culture is used as a source of nutrients for crops grown in hydroponics system. The present study was conducted at the Agriculture Research and Development Center, Sita Eliya, Nuwara Eliya, Sri Lanka during November 2015 to January 2016, to compare the yield of lettuce (Lactuca sativa L.) grown in hydroponics using fish effluents and inorganic fertilizer. The experiment was laid in a Completely Randomized Design with 5 treatments and 4 replicates. The different nutrient solutions used as the treatments of this experiment were water (T1), Albert’s solution (T2), Catla waste water (T3), Common Carp waste water (T4) and Tilapia waste water (T5). Each nutrient solution was tested for its nutrient composition, temperature, pH and electrical conductivity throughout the experimental period. The plant growth and yield parameters measured were plant height (cm), number of leaves, canopy diameter (cm), root length (cm), fresh weight of plant, leaves and roots (g), dry weight of leaves and roots (g) and, yield (ton/ha). The fish related parameters measured were body weight (g), initial and final stocking density (g/m3) and the mortality percentage. The results showed that T2 stood out (p<0.05) with the highest plant height (12.27cm), canopy diameter (14.80cm), number of leaves (12) and root length (15.04cm), exhibiting a vigorous growth compared to the other treatments. A remarkable yield and shoot and root weight (fresh and dry) were also shown by T2 over the other treatments. Fish waste water in T3, T4 and T5 did not fulfill the nutrient requirement of lettuce due to the limited nutrients; nitrogen, phosphorus and potassium) produced by fingerlings. Therefore, these fish waste solutions need to be improved by increasing the feed quality and selecting fish within a suitable age range in order to obtain a yield comparable to T2, which is the commercially available Albert’s solution.

Biodegradability and bioavailability of dissolved substances in aquaculture effluent: Performance of indigenous bacteria, cyanobacteria, and green microalgae

Aquaculture is a controlled aquatic farming sector and one of the most important human food sources. Fish farming is one of the predominant, fast-growing sectors that supply seafood products worldwide. Along with its benefits, aquaculture practices can discharge large quantities of nutrients into the environment through non-treated or poorly treated wastewater. This study aims to understand the nutrient composition of fish wastewater and the use of indigenous bacteria, cyanobacteria, and microalgae as an alternative biological treatment method. Wastewater samples from a local fish farming facility were collected and treated using six different species of cyanobacteria and microalgae include Chroococcus minutus, Porphyridium cruentum, Chlorella vulgaris, Microcystis aeruginosa, Chlamydomonas reinhardtii, and Fischerella muscicola. All the samples were incubated for 21 days, and the following parameters were measured weekly: Chemical oxygen demand (COD), phosphate, total dissolved nitrogen, and dissolved inorganic nitrogen. In addition, dissolved organic nitrogen (DON), bioavailable DON (ABDON), and biodegradable DON (BDON) were calculated from the mass-balance equations. Colorimetric and digestive methods were used for the parameter measurements. The results showed that C. reinhardtii reduced the soluble COD concentration by 74.6 %, DON by 94.3 %, and phosphorous by more than 99 %. Moreover, M. aeruginosa, and C. minutus significantly reduced inorganic nitrogen species (>99 %). This alternative fish wastewater treatment method was explored to gain insight into fish wastewater nutrient composition and to create a sustainable alternative to conventional fish wastewater treatment methods.

Insect-based fish feed in decoupled aquaponic systems: Effect on lettuce production and resource use.

The utilisation of insect meal-based fish feed as a substitute for conventional fish meal-based fish feed is considered as a promising innovative alternative to boost circularity in aquaculture and aquaponics. Basic research on its use in aquaponics is limited. So far, no reports on the effects of fish waste water, derived from a recirculating aquaculture system using Black Soldier Fly (BSF) meal-based diets, were available on the growth performance of lettuce. Therefore, this study aimed to compare the effect of reusing fish waste water from tilapia culture (as a base for the nutrient solution) fed with a fish meal-based diet (FM) and a BSF meal-based diet on resource use and lettuce growth in decoupled aquaponic systems. A conventional hydroponics nutrient solution (HP) served as control, and inorganic fertilisers were added to all nutrient solutions to reach comparable target concentrations. The experiment was conducted in a controlled climate chamber in nine separate hydroponics units, three per treatment. Lettuce fresh and dry weight, number of leaves, relative leaf chlorophyll concentration, water consumption, and the usage of inorganic fertilisers were measured. Micro- and macronutrients in the nutrient solutions were monitored in time series. Similar lettuce yield was seen in all treatments, with no significant effects on fresh and dry weight, the number of leaves, and relative chlorophyll values. Water use per plant was also similar between treatments, while the amount of total inorganic fertiliser required was 32% lower in FM and BSF compared to HP. Higher sodium concentrations were found in the FM nutrient solutions compared to BSF and HP. The results confirm that BSF-based diet is a promising alternative to FM-based diet in aquaponics with no negative effects on lettuce growth. Additionally, BSF-based diet might be beneficial in intensive, professional aquaponics applications due to the lower sodium concentration in the nutrient solution.

Utilizing fish wastewater in aquaponic systems to enhance anti-inflammatory and antioxidant bioactive compounds in Sarcodia suae

Aquaculture wastewater, rich in organic nutrients, is an essential environmental factor. When applied to seaweed cultivation systems, this wastewater holds the potential to notably increase the growth rate and carbon capture of Sarcodia suae. Sarcodia suae has the potential to be a healthy food due to its various biological activities; however, its chemical composition has yet to be completely defined. In this study, we applied a UHPLC-HRMS-based foodomics strategy to determine and classify possible bioactive metabolites in S. suae. From pooled seaweed samples (S. suae cultured in filtered running, FR, aquaponic recirculation, AR systems), we identified 179 and 146 compounds in POS and NEG modes, respectively. These compounds were then classified based on their structures using the Classyfire classification. Results show that S. suae in AR exhibited higher growth performance, and ten upregulated metabolites were determined. We also validated the anti-inflammatory and antioxidative bioactivities of some selected compounds. Our study provided important insights into the potential use of fish wastewater in aquaponic systems to profile and produce bioactive compounds in S. suae comprehensively. This has significant implications for the development of sustainable food and the promotion of environmental health.

Fish Wastewater and Fish Scale: A Corn Soil Enhancer

This study was conducted to determine the effects of fish waste water and fish scale as soil enhancer for the growth of sweet corn. The Experimental Research design with different treatments such as treatment 1 for 100% fish scale, treatment 2 for 100% fish waste water, treatment 3 for 50% fish scale and 50% fish water waste, and treatment 4 for commercialized fertilizer were employed for the growth of corn plants in terms of height, girth of stem, number of leaves and length of leaves. Mean and Post hoc analysis were used for the data analysis. It was found out that treatment 3 which was 50% fish scale and 50% fish water waste and treatment 4 which was commercialized fertilizer had the highest average growth of corn plants in all parameters. However, 100% fish scale and 100% fish water waste had the lowest average growth of corn plants in all parameters. Meanwhile, it was found out also that there was a highly significant difference in the effect of treatment 1 as contrasted among the other treatments of fertilizer. The same with treatment 2 as contrasted with treatment 3 and 4. However, the analysis found no significant difference on the effect of treatment 3 and 4 on the growth response of corn plants in all parameters.

Plant nutritional value of aquaculture water produced by feeding Nile tilapia (Oreochromis niloticus) alternative protein diets: A lettuce and basil case study

Societal Impact StatementRefining circular multitrophic food production methods, which integrate plant, fish, and insect outputs, is imperative for environmental sustainability. Our findings suggest that the right protein choices in fish feed, like black soldier fly meal and poultry meal, can notably enhance the nutrient profile of fish waste water. This, in turn, is conducive for hydroponic cultivation, enhancing the nutritional attributes of plants like basil and lettuce. As we reduce environmental impact and optimize resource use, it is evident that our food ecosystems are deeply intertwined. Harnessing these synergies could redefine our approach to food production, paving the way for a more sustainable global future.Summary Optimization of nutrient use efficiencies in circular multitrophic food production systems (i.e., plant, fish, and insect production) is crucial for sustainability. This study tested how protein ingredient choice in fish feed influences the plant nutritional value of the fish waste water when used for hydroponic crop production. Waste water samples were obtained from recirculating aquaculture systems (RAS) in which Nile tilapia (Oreochromis niloticus) were fed different single protein source diets—black soldier fly meal (BSFM), poultry by‐product meal (PM), poultry blood meal (PBM), and fish meal. Water was analyzed for plant nutrients and used for lettuce and basil cultivation to evaluate their suitability for hydroponic crop production—viz. yield, mineral nutrient, and selected secondary metabolite levels. BSFM RAS water had the highest concentrations of K, Mg, and micronutrients (Cu, Mn, Mo, Zn) of the RAS waters, whereas PM RAS water contained the highest P concentration and had a mean pH of 6.5 closer to the optimum pH for hydroponic plants. These RAS waters consequently lead to the highest yields in basil and lettuce indicating the importance of the aforementioned factors. From a plant production perspective, BSFM appears promising as a protein source in fish feeds for aquaponics. Usage of RAS waters for plant production helps reduce (i) environmental impact of RAS water and (ii) resource input in plant production. Longer term RAS trials should be conducted to determine the maximum nutrient concentrations achievable during fish production with diets including BSFM as the main protein source.

Characterisation of key components of biofertiliser produced from mackerel wastewater and commercialisation feasibility analysis of the biofertiliser production process for wastewater valorisation

Microbial production of biofertiliser attracts much attention due to complete reuse of fish wastewater and enhanced yields in agriculture. Herein, key components of biofertiliser (cells and hydrolysates) were characterised to determine the quality of biofertiliser from mackerel wastewater (MWW). Through fed-batch biodegradation, a high number (5.33 × 109 CFU/mL) of viable cells and rich low-molecular-weight hydrolysates were obtained with a high degree of hydrolysis (48.1%). Cells exhibited plant growth-promoting activities, while hydrolysates (<2 kDa) exhibited high antioxidant activities of 84.17% for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 98.45 for 2,2′-azino-bis(ethybenzthiazoline-6-sulfonic acid) (ABTS). During hydroponics cells colonised wheat roots, enhancing wheat growth, health and antioxidant activities. Synergistic effects of key components on plant growth, health and functionality were observed in lettuce after 30 days of hydroponic growth, significantly higher than those of controls and comparable with those of a commercial fertiliser. Economic analysis of the commercial feasibility of biofertilser production revealed the effects of scale-up, and the predicted profitability of biofertiliser production from raw MWW in 150 L was $14,796.13/year. Therefore, MWW reuse could be beneficial for decreasing the environmental impacts and improving the efficiency of sustainable agriculture.

Treatment of Fish-Processing Wastewater Using Polyelectrolyte and Palm Anguish

Fish-process wastewater industries are a significant source of environmental pollutions and biohazard to humans and other living organisms due to suspended organics, phosphorus, and nitrate that causes environmental damage. In this study, the treatment of two types of fish wastewater was examined by applying chemical and physical methods. The chemical treatments using positive polyelectrolyte with a concentration of 25 ppm reduced the turbidity of fish wastewater by 50%; conductivity was reduced by 50% and pH was reduced from 8 to 7.2. Meanwhile, using negative polyelectrolyte and mixed polymers reduced the turbidity of fish wastewater by 30%. For applying natural material as a physical adsorbent, several natural materials were examined: ocimum leaves, Boswellia sacra leaves, Al-Shakher leaves, tephrosia leaves, neem leaves, mentha leaves, jand peel, neem wood, ocimum fruit, olive fruit peel, and palm anguish for the treatment of the fish wastewater. The initial tests indicated that the best material was palm anguish. FTIR, SEM, and EDS were used for the characterization of palm anguish. The selected material was treated with 1 M of NaOH solution. Different bed heights (10, 20, and 30 cm) of Palm anguish were applied. The results showed 80% and 85% reduction in the turbidity in both types of fish wastewater, especially with a bed height of 30 cm of the fish wastewater treated with NaOH, respectively. Notably, this study distinguishes itself by utilizing polyacrylamide flocculants of varying densities and by employing palm anguish as a natural adsorbent, which can sufficiently improve the treatment of fish-processing wastewater.

Performance of Sediment Microbial Fuel Cells in Generating Electricity using Fish Wastewater and Shrimp Wastewater as a Nutrient and Their Effect on Waste Quality

Sediment Microbial Fuel Cell (MFC) is a technology that can convert chemical energy into electrical energy through the process of nutrient degradation by microbes. Sediment taken from the bottom of shrimp ponds was added as a source of microbes, while fish and shrimp wastewater were used as a source of nutrients for microbes. This study aims to measure the performance of the SMFC system on fish effluent and shrimp effluent to produce bio-electricity while reducing the waste load. The research method was experimental laboratories. The treatment given was the different types of electrodes, namely zinc-copper and aluminum-copper. In addition, 0.2 M KMnO4 electrolyte solution was used. This study consisted of four stages: the manufacture of nutrients from fish and shrimp wastewater, the manufacture of a dual chamber MFC bioreactor, the measurement of electrical values, and the analysis of waste quality. Experiments were carried out for 30 days by measuring electricity every 24 hours. The average value of electricity generated in the nutrients of fish wastewater with Zn/Cu electrodes was 0.705 V and Al/Cu was 0.472 V. Meanwhile, the average value of electricity in shrimp wastewater nutrients with Zn/Cu electrodes was 0.630 V and Al/Cu was 0.625 V. The number of colonies after adding sediment in the shrimp wastewater sample were 8.9 x 106 CFU/mL, the fish wastewater sample was 9.5 x 106 CFU/mL. It indicates the presence of microorganisms that play a role in the SMFC system

Studi Pemanfaatan Limbah Cair Ikan dan Udang sebagai Substrat dalam Produksi Listrik pada Sistem Microbial Fuel Cell (MFC)

Microbial fuel cell (MFC) is a technology that utilizes bacteria in organic medium that can convert chemical energy into electrical energy. This technology can be used to treat fishery waste and shrimp waste which is rich in organic matter. This study aimed to measure the performance of the MFC system on fishery wastewater and shrimp wastewater as a means of producing bio-electricity while reducing the waste load. This study used different types of electrodes, including zinc, aluminum, copper, and carbon graphite. This technology used 0.2 M KMNO4 electrolyte solution. The research method includes three stages; production of fishery wastewater and shrimp wastewater, assembly of a dual chamber MFC bioreactor, and measurement of waste electrical energy produced. The value of electricity production with the highest average in fishery wastewater was obtained by adding electrolyte solution to the Zn/Cu electrode during 117 hours of observation were 6.86 mA with a potential difference of 1.469 V meanwhile in shrimp wastewater was obtained by adding electrolyte solution to the Al/Cu electrode were 4.38 mA with a potential difference of 1.335 V.This study can be concluded that higher electricity production is obtained from the utilization of fish wastewater using Zn/Cu electrode.

Effect of Fish Water Waste Liquid Organic Fertilizer on Strawberry Flowering (Fragaria Sp)

Strawberry plant (Fragaria sp) is one of the fruit plants grown in Indonesia, although it is not native to Indonesia. The growth of strawberry farmers continues to increase from year to year, especially those outside Lombok Island. This research was conducted at the Green house of the Jeruk Manis Farmer Group, Pejeruk Village, Mataram City. This research was conducted for 4 months starting from April 2022 to August 2022. This research was carried out experimentally using a complete randomized design with 6 treatments and 3 replications so that 18 experimental units were obtained, and each polybag consisted of 2 plants so that there were 36 plant units in total . The treatment given was the difference in concentration of POC fish waste water with concentrations (0.0, 1.5, 2.0, 2.5, 3.0, 3.5) ml/1 liter of water. Parameters observed were plant height (cm), number of leaves (strands), age of flowering, age of first harvest. The research results were analyzed statistically using variance. If the data obtained shows a real effect, a further test is carried out with Ducan's New Multiple Range Test (DNMRT) at the 5% level. Based on the results of the research that has been done, it can be concluded that the application of fish waste liquid organic fertilizer at a dose of 3.5 gives the best results on generative growth parameters.

Potential use of entomopathogenic and mycoparasitic fungi against powdery mildew in aquaponics

Aquaponics has the potential to produce sustainable and accessible quality food through the integration of hydroponics and aquaculture. Plants take up dissolved nutrients in fish wastewater, allowing water reuse for fish. However, the simultaneous presence of fish and plants in the same water loop has made phytosanitary treatments of diseases such as powdery mildew problematic due to risks of toxicity for fish and beneficial bacteria, limiting its commercialization. Entomopathogenic and mycoparasitic fungi have been identified as safe biological control agents for a broad range of pests. This study aimed to investigate the efficacy of entomopathogenic fungi, Lecanicillium attenuatum (LLA), Isaria fumosorosea (IFR), and mycoparasitic fungus Trichoderma virens (TVI) against Podosphaera xanthii. Also, we investigated the possible harmful effects of the three fungal biocontrol agents in aquaponics by inoculating them in aquaponics water and monitoring their survival and growth. The findings showed that the three biocontrol agents significantly suppressed the powdery mildew at 107 CFU/ml concentration. Under greenhouse conditions (65-73% relative humidity (RH)), a significant disease reduction percentage of 85% was recorded in L. attenuatum-pretreated leaves. IFR-treated leaves had the least AUDPC (area under disease progress curve) of ~434.2 and disease severity of 32% under 65-73% RH. In addition, L. attenuatum spores were the most persistent on the leaves, the spores population increased to 9.54 × 103 CFUmm-2 from the initial 7.3 CFUmm-2 under 65-73%. In contrast, in hydroponics water, the LLA, IFR, and TVI spores significantly reduced by more than 99% after 96 hrs. Initial spore concentrations of LLA of 107 CFU/ml spores were reduced to 4 x 103 CFU after 96 hrs. Though the results from this study were intended for aquaponics systems, relevance of the results to other cultivation systems are discussed.

Pemanfaatan Limbah Kultur Batch Bioreaktor dan Biochar untuk Meningkatkan Kesuburan Tanah

The purpose of study was to determine the effects of aeration treatment on fish wastewater quality as a liquid organic fertilizer and fish wastewater watering treatment as a liquid organic fertilizer and a biochar application on nutrient content of lettuce and soil chemical properties. This study used a non factorial randomized block design. Treatments combination were watering freshwater frequency (W0: without watering; W1: watering twice a week; and W2: watering 4 times a week) and rice husk biochar dose (B0: without rice husk biochar; B1: 10 g rice husk biochar per polybag; and B2: 20 g rice husk biochar per polybag). The research parameters included: fish culture wastewater quality (pH, Biological Oxygen Demand, Chemical Oxygen Demand, NH3-N, NO3, NO2, Dissolved Oxygen, electrical conductivity, and temperature), plant nutrient content analysis (N, P, and K), and soil chemical analysis (pH, organic C, total N, C/N ratio, available P, and exchangeable K). The results showed that the quality of wastewater after aeration for 4 days met the water criteria to cultivate plants. The nutrient contents in the soil showed criteria for neutral soil pH, very low organic C, very low total N, medium C/N ratio, very high available P, and low exchangeable K. Although the nutrient content in the soil was low, the concentrations of N (1.87-3.08%), P (0.16-0.21%), and K (2.35-3.43%) nutrients in the plant were sufficient for lettuce growth. The combination treatment of watering wastewater 4 times a week and rice husk biochar 20 g per polybag gave better results to increase soil fertility and lettuce plant nutrients.&#x0D; &#x0D; Keywords: liquid waste, plant nutrients, soil amendment, soil chemistry

Influence of calcium macronutrient on tip burn occurrence in hydroponically cultivated lettuces

Tip burn in hydroponics lettuce is an undesirable phenomenon identified by necrotic breakdown of marginal tissue of leaves. A deep-water culture hydroponics system was designed to determine the effect of increasing nutritional calcium concentration and varying nutritional calcium sources in alleviating the tip burn development for the hydroponics growth of lettuce (Lactuca sativa). Lettuces was cultivated separately in an untreated fish wastewater (150mg/L) and four treated fish wastewaters with calcium addition by calcium hydroxide and calcium carbonate to concentrations of 250 and 350mg/L respectively. Increasing calcium concentration from 150 to 350mg/L demonstrated not only an increase in tip burn incidence by 33.33% (calcium carbonate) and 50% (calcium hydroxide), but a slower plant growth in comparison with lettuces cultivated at 150mg/L. Besides, lettuces treated by calcium carbonate has greater leaf calcium concentrations by 48.17% at constant calcium concentration, attributed to its high solubility to release more Ca2+ ions in fish wastewater for plant adsorption. Results suggest that the addition of calcium carbonate to fish wastewater for hydroponics cultivation is more suitable for reducing the tip burn occurrence and growth inhibition at concentrations up to 150mg/L.