Polymer Dosage Research Articles

Irrigation levels and use of hydro retainer polymer in greenhouse lettuce production

ABSTRACT One of the potential alternatives to improve the use of water resources is the use of hydro retainer polymer applied to the soil. The objective of this study was to evaluate how irrigation levels and doses of hydro retainer polymer interfere in the production of ’Vanda’ lettuce. The experiment was carried out from December 2017 to January 2018 under protected environment in the Instituto Federal Goiano, Urutaí Campus, Goiás State, GO, Brazil (17º 29’ 10” S of latitude, 48º 12’ 38” W of longitude and 697 m of altitude). The work tested four irrigation levels of 50, 75, 100 and 125% of the evaporation obtained daily by the hook micrometer and five doses of hydrogel polymer (0, 50, 100, 150 and 200 g plant-1). The experimental design was a randomized block design in a scheme of split-plot and four blocks. Canopy fresh and dry mass, plant height, number of leaves and productivity were evaluated. There was 29.24% increase in the dry mass comparing the hydro retainer polymer doses of 0 and 169.28 g and an increase of 14.36% of the height of plants when compared with the irrigation levels of 50 and 125%. The use of a hydro retainer polymer provided a significant increase in all the evaluated productive variables. The irrigation levels influence the fresh mass from aerial part, plant height and productivity. The productivity increased 18.42% for the irrigation levels used and the highest estimated values were presented in the dose of 157.49 g (14.46 t ha-1) hydro retainer polymer.

Removal of Cryptosporidium surrogates in drinking water direct filtration

Pilot-scale direct filtration challenge experiments were conducted to determine the impact of chemical pretreatment and filter design on the removal of Cryptosporidium surrogates dosed into the filter influent water at low temperatures (Average 0.5 °C). Copolymers-modified microspheres were identified as representative Cryptosporidium oocysts surrogates based on our previous findings and were used to evaluate the oocysts filtration removal at this pilot-scale study. The operational parameters examined included coagulant type (aluminum sulfate (alum) versus polyaluminium chloride (PACl)), filter aid polymer type (polyamine Magnafloc® LT-7981 versus poly(Dimethyl Diallyl Ammonium Chloride) (polyDADMAC) Magnafloc® LT-7995) and dose (0.5 versus 2.0 mg/L), and filter configuration (regular versus deep bed filters). The study found that higher Cryptosporidium surrogate removal was associated with higher polymer dose (2 mg/L) of polyDADMAC polymer and the deep bed filter configuration. The difference in surrogate removal between PACl and alum was no significant at cold temperature conditions tested. The deep bed filters were associated with higher surrogate removal, while exhibiting lower rates of flow reduction and longer filter run time. This work emphasizes the importance of optimizing chemical pretreatment and filter configuration for removing surrogates of Cryptosporidium oocysts in cold-water conditions in granular media water filtration processes. This pilot-scale study also demonstrated the exceed 2.5-log removal of Cryptosporidium surrogates (required from Guideline for Canadian Drinking Water Quality) can be achieved in the direct filtration during Edmonton cold-water condition when the pretreatment processes are optimized using 0.454 mg/L of alum as Al with addition of 0.5 mg/L poly DADMAC.

Physical and chemical treatment of landfill leachate - recycling of nitrogen

This paper presents a new type of plant to treat leachate from a municipal landfill. The plant is situated in Eskilstuna (pop. 90 000) a town-situated approx. 110 km west of Stockholm. The main purpose of the plant is to reduce nitrogen, phosphorus, COD and heavy metals in the leachate from the Lilla Nyby landfill in Eskilstuna. Lilla Nyby landfill is a municipal landfill, which has been used for nearly 50 years to deposit industrial and municipal waste from the Eskilstuna community. A drainage system in the landfill collects the leachate which is stored/equalized in a basin with a maximum volume of 40 000 m3 . The yearly amount of leachate is about 120-160 000 m3 • The leachate is pumped to the treatment plant. The demands of the authority to meet are as follows: NH3 (ammonium nitrogen) < 25 mg/I COD < 200 mg/I Total phosphorus (tot-P}< 0,3 mg/I The normal composition of the untreated leachate is NH3 (ammonium nitrogen)e- 250 mg/I COD - 400 mg/I Total phosphorus (tot-P)- 1,0 mg/I Thus it is necessary to reduce the ammonium nitrogen with -90% and COD with -50%. A request of a total tender with function warranty was made 2001. 6 contractors offer tender, 3 tenders are judged to be interesting, Pronea, Lackeby and Stork Engineering. Pronea offers chemical precipitation+ammonia-stripping/ absorption+activated coal-filtration, Lackeby offers SBR-treatment alt. NF+ ammoniastripping/ absorption and Stork offers evaporation or reversed osmosis RO). After a technical/economical evaluation the Pronea offer was considered to be the most interesting and was purchased. The process produces a useful chemical, ammonium sulphate, which can be used as an additive to the bio fuelled (wood chips) boiler in Eskilstuna. Two useful results will be reached: l) The corrosion in the furnace caused by alkali metals will be reduced and 2) the ammonia additive to reduce NOX in the flue gases can be reduced. The plant works as follows: 3 • Leachate is pumped to the plant (dim. capacity 20 m /h) • Reduction of pH to 3 with sulphur acid and CO2-stripping (reduce the buffer capacity) • Rise of pH to 11,0 with sodium hydroxide and precipitation with ferric chloride (FeCb). Dosage of polymers to enhance the build up of flocks. • Flock separation in lamella separator • Further flock separation in continuous sand filter • Rise of temp. to 50-60 0C through heat exchange • Ammonia-stripping + ammonia-absorption • Filtration in activate coal filter+ pH-adjustment Nitrogen in the leachate (ammonium nitrogen) together with sulphuric acid forms ammonium sulphate, at a concentration of 40% The plant is not yet approved and taken over by the purchaser. Much work has been needed to trim the process in the plant. A lot of problems have appeared and been solved. Some examples of the most essential items: • Foam forming after the CO2-stripper • Transport of water drops from the ammonia-stripper to the ammonia-absorber • Break down of process pumps for leachate (carbonate deposits), dosage pumps and valves • Leakage of sulphuric acid and sodium hydroxide • Sludge escape from the lamella separator (bad separation) • Clogging in heat exchangers and stripper tower(carbonate deposits) • Wrong placed flow meters Preliminary results are: • At least 90% ammonia reduction is possible • Good phosphorus- and metal reduction • If approved COD-reduction can be reached is still to be proved • Good quality of produced ammonium sulphate • The need of chemicals and energy yet to be evaluated

Effects of inorganic cations and organic polymers on the physicochemical properties and microfabrics of kaolinite suspensions

The effects of inorganic cations and organic polymers on the physicochemical properties and microfabrics which including the floc size distributions of kaolinite suspensions were systematically investigated by batch sedimentation tests. Kaolinite surface charges, salt concentrations and polymer polarity as well as polymer dosage were found to be the key factors that affect the particle associations, floc sizes, zeta potential, and turbidity of a kaolinite suspension. The relationship between flocs sizes, turbidity, and zeta potential of kaolinite sediments were established and the significance of understanding the polymer induced flocculation and aggregation of suspended kaolinite sediments was discussed. Assisted by the zeta potential measurements, an increase of ionic strength was found to compress the electrical double layer (EDL) of kaolinite and result in imbalance of the interparticle forces, thus the particle associations and floc sizes varied significantly. The addition of polymers was found to facilitate flocculation of kaolinite through long-range polymer bridging and short-range ion-dipole interaction, including the hydrogen bonding and Colombian interactions, which in turn affected the flocs size, zeta potential, and turbidity of the suspensions. Test results also showed that the clay-polymer suspensions possessed a unimodal lognormal particle size distribution (PSD) which leading to a more quantitative understanding of floc sizes of suspended sediments.

CNash - A novel parameter predicting cake solids of dewatered digestates

Efficient digestate dewatering is crucial to reduce the volume and transportation cost of solid residues from anaerobic digestion (AD) plants. Large variations in dewatered cake solids have been reported and predictive models are therefore important in design and operation of such plants. However, current predictive models lack validation across several digestion substrates, pre-treatments and full-scale plants. In this study, we showed that thermogravimetric analysis is a reliable prediction model for dewatered cake solids using digestates from 15 commercial full-scale plants. The tested digestates originated from different substrates, with and without the pre-AD thermal hydrolysis process (THP). Moreover, a novel combined physicochemical parameter (C/N•ash) characterizing different digestate blends was identified by multiplying the C/N ratio with ash content of the dried solids. Using samples from 22 full-scale wastewater, food waste and co-waste plants, a linear relationship was found between C/N•ash and predicted cake solids for digestates with and without pre-AD THP. Pre-AD THP improved predicted cake solids by increasing the amount of free water. However, solids characteristics like C/N ratio and ash content had a more profound influence on the predicted cake solids than pre-AD THP and type of dewatering device. Finally, C/N•ash was shown to have a linear relationship to cake solids and reported polymer dose from eight full-scale pre-AD THP plants. In conclusion, we identified the novel parameter C/N•ash which can be used to predict dewatered cake solids regardless of dewatering device and sludge origin.

Removal of lead ions from wastewater using novel Schiff-base functionalized solid-phase adsorbent

ABSTRACTThis article discusses the synthesis, characterization and lead ions sorption capability of a novel recyclable Schiff-base anchored cross-linked polyacrylamide. The synthesized polymeric adsorbent was characterized by FT-IR technique, XRD and SEM analysis. Sorption parameters, such as solution’s pH, contact time, polymer dose, lead ions initial concentration, etc., were studied and optimized. Experimentally, the optimum sorption pH was around 5.0 and the sorption equilibrium was attained after 30 min. Under the optimal conditions, the maximum sorption capacity was found to be 355 mg/g, which is considered high when compared with different adsorbents. Effect of interfering ions on the sorption capacity was explored. Sorption isotherms, kinetic and thermodynamic studies were considered to identify the sorption behavior of the new polymeric adsorbent. Sorption isotherm studies showed that the maximum sorption capacity was attended as a result of homogeneous monolayer sorption of lead ions on the surface of the synthesized polymeric adsorbent. The mechanism of lead ions sorption by the synthesized polymeric adsorbent was found to be chemisorption complexation mechanism. Moreover, kinetic studies revealed that the sorption process followed a pseudo second order kinetic model. Thermodynamic data depicted that the sorption process is spontaneous, reversible and exothermic in nature. Experiments on elution and reusability of the synthesized polymeric adsorbent were executed and the results showed its validity for reuse for at least four cycles with 11% loss in its original capacity. Finally, the applicability of the synthesized Schiff-base anchored solid phase adsorbent for the removal of lead ions from industrial wastewater was explored and the results indicated its good removal efficiency.

Anomalous KHI-Induced dissociation of gas hydrates inside the hydrate stability zone: Experimental observations & potential mechanisms

In the past decade, the low dosage hydrate inhibitors (LDHIs) - which include kinetic hydrate inhibitors (KHIs) and anti-agglomerants (AAs) - have seen increasing use for gas hydrate prevention in hydrocarbon production operations, offering significant CAPEX/OPEX advantages over traditional thermodynamic inhibitors (e.g. methanol, glycols). Typically dosed at < 2.5% in produced water, KHIs were historically considered primarily as hydrate nucleation inhibitors, although in recent years focus has shifted towards their powerful crystal growth inhibition properties. Beginning at low aqueous concentrations, KHI polymers induce a number of highly repeatable, well-defined, hydrate crystal growth inhibition (CGI) regions as a function of subcooling, varying from complete inhibition, through long induction times and reduced growth rates, to final failure/uninhibited growth. This behaviour can be used to robustly assess KHIs for field use, as we have previously demonstrated through development of the KHI CGI evaluation method, which is now used as standard by a number of laboratories. During CGI testing, it is not uncommon to observe anomalous (should be stable thermodynamically) hydrate dissociation in the presence of KHIs, although very little is understood regarding this phenomenon. In this work, we present the initial findings of experimental studies aimed at investigating this anomalous dissociation for different commercial base polymers. Results demonstrate that, in addition to inhibiting hydrate growth/nucleation, low dosages (e.g. 0.5% and 0.25%) of KHI polymers can induce partial or complete hydrate dissociation, with this process largely generic to different KHIs. However, some KHI polymers cause catastrophic hydrate growth after nucleation begins and these polymers show no ability to dissociate hydrates, so this hydrate dissociation ability is not universal to all KHI Polymers. The cause of this dissociation is unclear, although it is postulated to result from interactions between the KHI and inherent hydrate morphological and/or structural changes. In addition to improving confidence in KHI field use, findings potentially have novel applications with respect to hydrate plug remediation and gas production from naturally occurring hydrates in oceanic/permafrost sediments.

Strength Improvement of NC-SwBKP Sheets with PAE-PVA Pre-mixed Complexes (I): Effect of Mixing Ratio and Dosages of Polymers

Strength Improvement of NC-SwBKP Sheets with PAE-PVA Pre-mixed Complexes (I): Effect of Mixing Ratio and Dosages of Polymers

Comparative Pharmacokinetics and Biodistribution of Etoposide in a Polymer Dosage Form and as Free Drug Substance

A polymer dosage form of etoposide (PFE) was obtained as submicron particles based on the copolymer of lactic and glycolic acids (PLGA). Pharmacokinetics and biodistributions of etoposide in rat blood and organs after a single i.p. injection of the polymeric form and etoposide drug substance at doses of 10 mg/kg (of active ingredient) were compared and showed that absorption and elimination of etoposide from rat organs slowed if the PFE was used. The increases of T1/2 and MRT and decreases of Kel, Cmax/AUC(0 – 48), and Cl were indicative of this. Liver and lungs had the greatest tissue availability (ft) for the PFE. Etoposide accumulation in tumor tissue was studied after a single i.p. injection of PFE and etoposide drug substance at doses of 25 mg/kg to mice with grafted Ca755 murine breast adenocarcinoma. The etoposide distribution coefficient between blood and tumor tissue after 1 and 24 h was greater for the PFE, indicating the accumulation of etoposide in tumor tissue was greater if the PFE was used.

Deleterious effects of soluble extracellular polymeric substances on polyacrylamide demand for conditioning of anaerobically digested sludge

High polyacrylamide (polymer) demand for conditioning of sludge, especially anaerobically digested sludge (ADS), is a major issue for the water industry. Currently, this problem is being investigated and the reasons for doing so are varied. It has been demonstrated that excess amounts of soluble extracellular polymeric substances (EPS) can lead to high polymer demand for conditioning. This study developed a simple and unique yet effective method for quantifying the contribution of soluble EPS to conditioning polymer demand. It did this by measuring absorbance at 191.5 nm wavelength of the supernatant derived from conditioned ADS. Experimental results confirmed that approximately 87 wt% of soluble EPS interacted with polyacrylamides during the conditioning process. Furthermore, they revealed that a specified amount of soluble EPS could not be removed by polymer flocculation despite high polymer dosage. This study concluded that about 86 wt% of the polyacrylamide used for conditioning was consumed solely by soluble EPS. These results confirm the important role of reducing this EPS fraction in ADS in order to curtail significant chemical costs for sludge conditioning and dewatering.

Study on mechanical properties of polymer pervious cement concrete

The effects of polymer type, polymer dosage, concrete dosage per unit volume and water content on compressive strength and permeability coefficient of polymer permeable cement concrete were studied through experiments. The results show that the addition of polymer can improve the compressive strength of permeable concrete and have a lower influence on the permeability coefficient. Meanwhile, the compressive strength of the polymer permeable concrete increases with the increase of age, and the permeability coefficient tends to be stable with the change of age.

Optimizing acrylonitrile grafting onto delignified rice straw via response surface methodology towards its flame retardancy and durability intensification

The current research emphasizes on grafting of acrylonitrile onto pretreated rice straw for making low cost roofing material. The technique was improved by means of optimization for analyzing the impact of some parameters such as polymer dose, time and temperature of grafting. The optimization process applied in this research work was response surface methodology (RSM). The process was optimized through quadratic model of regression using ANOVA study (analysis of variance). 3-dimensional (3D) surface plots of the response and 2-dimensional (2D) contour analyses were adopted for further investigation of the collective synergies amidst the functional variables and to find out the optimal values for the percentage of grafting. The maximum grafting percentage was found at a grafting time of 97.59 min, grafting temperature of 77.52 oC and monomer concentration of 16.82 cubic centimeters (cc). At this condition, the highest percentage of polymer grafting from predictions according to the employed model was 60.07% which showed desirability equal to 1. The validation of these predictions was performed experimentally, with the observed result being 59.97% which is nearly equal to the theoretical values predicted by the model. Therefore, the model was able to deliver an optimized condition appropriate for polymer grafting onto rice straw for intensifying its durability.

Demonstration of on-chip quantum dot microcavity lasers in a molecularly engineered annular groove.

The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded on the same trench profile, a QD laser possesses a lifetime that is over 10 times longer. We have introduced a unique two-step quantum gain deposition process that has remarkably reduced the wavelength drifts of laser emissions in an aqueous environment by approximately 400%. The reconfigurable cavity platform in combination with an appropriately engineered quantum gain medium embedded onto it promises to enable photostable chip-scale coherent light sources for various photonic, chemical, and biochemical sensing applications.

Influence of polyelectrolyte architecture on the electrokinetics and dewaterability of industrial membrane bioreactor activated sludge

Improvement of sludge dewaterability is greatly hindered by the presence of large amounts of interstitial water molecules trapped in the sludge as a result of strong hydrophilic characteristics. This study has investigated the influence of six different polyacrylamide (PAM) flocculants with different molecular architecture (linear, slightly and highly branched), charge density (CD) and molecular weight (MW) on the electro-kinetics and dewatering of highly stable industrial membrane bioreactor (MBR) sludge. The impact of PAM on flocculation is manifested in the supernatant turbidity, particle zeta potential, sludge capillary suction time (CST), floc size and settleability. Turbidity removal and reduction in zeta potential are used to identify the optimum polymer dose. An optimum dose of 70 mg.L−1 has been determined for linear PAM of 40% CD. However, a highly-branched PAM, with the same CD, has shown an optimum value of 30 mg.L−1. In all cases, a turbidity removal of more than 99% and CST reduction of 51–64% is attained; the linear PAMs have resulted in the highest CST reduction. Higher PAM doses have resulted in larger flocs and the maximum particle size is observed at the saturation point. The reduction in sludge volume relates with the floc size and PAM dose. For sludge conditioning and dewaterability, highly branched PAM with low MW has shown superior performance over linear high MW PAM. Enhancement of flocculation and dewatering is correlated with the surface charge neutralization and bridging mechanisms.

Combining Chemical Flocculation and Disc Filtration with Managed Aquifer Recharge

Natural organic matter (NOM) is a growing concern for artificial recharge plants. In the future, it is predicted that warmer climates and more precipitation will cause higher NOM production in lakes and more NOM transport to lakes. This, coupled with increasing drinking water demand due to the population increase, is pushing operators of water treatment plants (WTPs) to find new ways to treat water. In this study, the possibility of reducing the organic load in infiltration basins through a compact pre-treatment technique utilizing microsieves, or disc filters, instead of bulky sedimentation basins and rapid sand filters after chemical flocculation to separate flocs, was investigated. The experiments were conducted using a laboratory-scale flocculator, bench-scale disc filters (10 µm and 40 µm), FeCl3, an anionic synthetic polymer, and water from Lake Vomb, a lake in southern Sweden. Raw water was flocculated using FeCl3 and the polymer, and the filtrated samples were analyzed by measuring UV–VIS absorbance, total organic carbon (TOC), and permeate volume. The results when using 10-µm and 40-µm disc filters demonstrate that it is possible to reduce NOM (by approximately 50%) and separate flocs from raw water. The experiments also highlight the importance of sufficient flocculation times and the use of appropriate polymer dosage to achieve higher permeate volumes and avoid residual polymers in the effluent. In this paper, the possibility of using this technique as a standalone treatment step or as a pre-treatment step in order to manage the aquifer recharge is demonstrated.

Frequency of irrigation with saline water in sugar-apple seedlings produced on substrate with polymer

ABSTRACT The objective of this work was to evaluate the growth of sugar-apple seedlings under irrigation management with saline water in a substrate with soil amendment. Treatments were obtained from the arrangement between polymer doses (0, 0.2, 0.6, 1.0 and 1.2 g dm-3) and levels of irrigation water electrical conductivity (0.3, 1.1, 2.7, 4.3 and 5.0 dS m-1), associated with irrigation frequencies (daily and every alternate day), and two additional treatments to evaluate container volume (1.30 and 0.75 dm3), using a randomized complete block design, with four replicates. At 120 days after sowing, the variables substrate salinity, stem diameter, plant height, number of leaves and Dickson quality index were determined. Data were submitted to analyses of variance, regression and contrast. Substrate salinity increased with the increase in irrigation water electrical conductivity and polymer doses. Growth and quality of the seedlings were reduced with increasing irrigation water salinity, and highest values of the variables were obtained in seedlings under daily irrigation. Container with larger volume led to higher growth. The use of hydrated polymer at the adopted levels had no effect on growth and quality of seedlings, requiring further studies. To produce sugar-apple seedlings with better quality, irrigation frequency should be daily and water electrical conductivity should be lower than 2 dS m-1.

Commissioning of a novel in-line rheometery system in a wastewater treatment plant for more efficient polymer dosing

Urbanisation is putting enormous pressure on wastewater treatment plant facilities. Optimising the liquid and sludge process streams in existing plants is one way of prolonging the life span of such installations. Many Wastewater treatment plants (WWTP) have sludge dewatering installations where treated wastewater sludge is dewatered using belt filter presses amongst others, before final disposal. One of the most expensive inputs in these plants is the polymers used as flocculants. Controlling the optimum dosing in the dewatering process cannot currently be done in real-time. It has been shown that huge savings can be made by optimising the dosing rates of polymers based on the sludge rheology.An Ultrasound Velocity Profiling (UVP) and pressure drop (PD) measurement system was specially designed and commissioned for a WWTP. The system was installed in a WWTP to measure the rheological properties of sludge in-line and in real-time prior to mechanical dewatering using a belt filter press. This non-invasive in-line system was able to accurately measure the rheological parameters in real-time in a 100 mm stainless pipe. It was shown for the first time what the maximum in-line yield stress is that is required for optimum dewatering based on a relationship determined between the yield stress and the total suspended solids in the filtrate exiting the belt filter press.

An evaluation of machine learning and artificial intelligence models for predicting the flotation behavior of fine high-ash coal

In this study, five different machine learning (ML) and artificial intelligence (AI) models: random forest (RF), artificial neural networks (ANN), the adaptive neuro-fuzzy inference system (ANFIS), Mamdani fuzzy logic (MFL) and a hybrid neural fuzzy inference system (HyFIS) were employed to predict the flotation behavior of fine high ash coal in the presence of a novel “hybrid” ash depressant consisting of polyacrylamide chains grafted onto aluminium hydroxide nanoparticles: Al(OH)3-PAM (Al-PAM). A total of 51 flotation tests were conducted on coal samples with 38% ash-content and a P80 of approximately 49 μm. Different influencing variables of coal flotation including polymer dosage, pH, polymer conditioning time, sodium metasilicate dosage (commercial dispersant), and the impeller speed were used as inputs for the models. The combustible recovery and ash content of coal reported to the concentrate were used as response variables (outputs). For AI model development, 80% of the total data was used for training phase and 20% was used for testing phase. Coefficient of determination (R2) and root-mean-square error (RMSE) were used as performance indicators of the models. The MFL model showed the best accuracy for the prediction of the combustible recoveries and the froth ash contents for this specific feed. However, in case of any significant change in the characteristics of the feed, these models would have to be re-trained using the data obtained through further physical experimentation and/or process model simulations. Moreover as these models are trained on laboratory scale data, these are only good for the predictions at laboratory scale.

Biomass of sugar-apple seedlings under saline water irrigation in substrate with polymer

ABSTRACT Application of saline water causes water and salt stress, changing the behavior of the plants. The aim of this work was to evaluate the accumulation and allocation of biomass in sugar-apple seedlings under frequencies of irrigation with saline water in a substrate with soil conditioner, as well as the effect of container volume. The treatments were obtained from the arrangement between polymer doses (0, 0.2, 0.6, 1.0 and 1.2 g dm-3) and electrical conductivity of irrigation water (0.3; 1.1; 2.7; 4.3 and 5.0 dS m-1), associated with irrigation frequencies (daily and alternated), plus two additional treatments to evaluate container volume (0.75 and 1.30 dm3), distributed in blocks. The evaluations were performed at 120 days after sowing. Irrigation frequency affected the variables, and the highest values were obtained with daily irrigation, except for root/shoot dry matter ratio. Increase in the electrical conductivity of the irrigation water inhibited biomass accumulation. The effect of the container was significant for daily irrigation; higher volume led to higher root, shoot and total biomass. Polymer doses did not affect the biomass of the seedlings. Daily irrigation with non-saline water favored biomass production in sugar-apple seedlings. In the production of sugar-apple seedlings, water with electrical conductivity below 1.0 dS m-1 should be used on a daily frequency of application in 1.30 dm3 containers.

MODELAGEM FUZZYPARA AVALIAÇÃO DA PRODUÇÃO DE MUDAS DE TOMATE CEREJA UTILIZANDO DIFERENTES DOSES DE POLÍMEROS E NÍVEIS DE IRRIGAÇÃO

The tomato is considered the second vegetable of economic importance in Brazil and for the success of its cultivation, depends to a large extenton the use of quality seedlings, since a well formed seedling will give rise to a plant with high productive potential. Adequate water availability is important to produce good seedlings, but failing that, commercial polymers inserted into the substrate can be used. The objective of this work was to study the effects on the development of cherry tomatoes in different doses of polymers applied to the substrate and different levels of irrigation until the transplant phase using fuzzy modeling. For this study, we used data from an experiment conducted at the Faculty of Technology of Presidente Prudente.The input variables of the developed system based on fuzzy rules were Polymer and Irrigation, and for both were defined 5 fuzzy sets. The output variables wereshoot length (CPA), root length (CR) and seedling dry mass (MSM). For the SBRF output variables, 5 fuzzy sets were also defined. The analysis of the effects of polymer doses and irrigation levels on tomato seedlings was performed using three -dimensionalgraphs and contour maps of the output variables. This analysis allowed us to conclude that, for irrigation levels below the maximum (daily irrigation), the use of 2 grams of polymers refers to the best conditions of the variables shoot length, root lengthand dry mass of the seedling.