A low-loaded constructed wetland was investigated with respect to phosphorus retention. Since the main long-term phosphorus retention mechanism is sedimentation and sediment accretion, the study focused on these processes. The purpose of the study was 1) to investigate how the calculated value of phosphorus retention (Pin – Pout), corresponded with the measured amount of phosphorus in the sediment, 2) to find out where in the wetland the phosphorus had accumulated, and in what form it was retained, and 3) to investigate the role of vegetation. The calculated value was 12 kg ha-1 and the measured value was 104 kg ha-1, which indicated the importance of internal phosphorus circulation, where plants probably take phosphorus from the underlying clay. Hence, vegetation could possibly increase the total phosphorus content in the wetland. The composition of phosphorus in the sediment was analysed using sequential fractionation. The dominating form of phosphorus in the sediment was iron-bound phosphorus (29 %). In total, 48 % of the phosphorus was stable, i.e. tightly bound in the sediment, and 35 % was relatively stable. The bioavailable fraction, which could cause eutrophication in downstream waters, was 17 % of the total phosphorus content, or 41 kg ha-1. The amount of total phosphorus was significantly higher near the inlet, compared to the outlet, which is explained by rapid sedimentation of particulate phosphorus entering the wetland. The phosphorus amount near the inlet represented 80 % of the total phosphorus load – which indicates the importance of internal circulation of phosphorus, both biological and geochemical.

<p>Waste Stabilisation Ponds (WSPs) are characterised by low phosphorus (P) removal capacity. Heterotrophic bacteria are principal microbial agents in WSPs in addition to algae. As treatment proceeds in WSPs, algal growth increases and pH rises, this has lead to believe that P removal is mainly through sedimentation as organic P algal biomass and precipitation as inorganic P. In activated sludge treatment plants (AS), microbial P removal has been improved and is termed as enhanced biological phosphorus removal. There was a need to establish whether it was possible to enhance P removal in WSPs. A performance assessment of pond system at the University of Dare s Salaam (UDSM), Tanzania, has shown that 90% of the P removed was in the primary pond (facultative) and the rest in the maturation pond (aerobic).</p><p>In these studies, a pure strain A. hydrophyla was isolated from an activated sludge wastewater treatment plant in Sweden. This plant has a train that functions with enhanced biological phosphorus removal. The strain was tested for P uptake in minimal media supplemented with glucose, succinate or acetate, grown aerobically and anaerobically/aerobically. This strain was able to take up P without having been subjected to the anaerobic phase. It was observed that P uptake was enhanced after the anaerobic phase with media supplemented with glucose, but not with succinate or acetate. Phosphorus uptake repeatedly followed the bacterial growth pattern with correlation coefficients of more than 95%. Therefore P removal has a direct correlation with bacterial growth.</p><p>Two isolates Acinetobacter sp. (isolated from the primary facultative pond) and E .coli (isolated from the maturation pond) were obtained from a tropical WSP treatment system at the UDSM. They were subjected to aerobic P uptake experiment similar to those of A.hydrophyla. The uptake per unit absorbance of bacterial growth was found to be comparable to that of A.hydrophyla, isolated from AS. These results showed that heterotrophic activity is important in WSPs. It is possible to enhance P removal in these systems by designing the primary ponds for maximum heterotrophic activity and probably enrichment.</p>

<p> </p><div><table style="height: 340px;" border="0" cellspacing="0" cellpadding="0" width="639" align="left"><tbody><tr><td style="padding: 0cm 7.1pt;" height="289" align="left" valign="top"><div style="border: 1pt solid windowtext; padding: 1pt;"><p class="MsoNormal" style="border: medium none; padding: 0cm;"><span style="font-size: 10pt;" lang="EN-GB">A low-loaded constructed wetland was investigated with respect to phosphorus retention. Since the main long-term phosphorus retention mechanism is sedimentation and sediment accretion, the study focused on these processes. The purpose of the study was 1) to investigate how the calculated value of phosphorus retention (P_in – P_out), corresponded with the measured amount of phosphorus in the sediment, 2) to find out where in the wetland the phosphorus had accumulated, and in what form it was retained, and 3) to investigate the role of vegetation. The calculated value was 12 kg ha^-1 and the measured value was 104 kg ha^-1, which indicated the importance of internal phosphorus circulation, where plants probably take phosphorus from the underlying clay. Hence, vegetation could possibly increase the total phosphorus content in the wetland. The composition of phosphorus in the sediment was analysed using sequential fractionation. The dominating form of phosphorus in the sediment was iron-bound phosphorus (29 %). In total, 48 % of the phosphorus was stable, i.e. tightly bound in the sediment, and 35 % was relatively stable. The bioavailable fraction, which could cause eutrophication in downstream waters, was 17 % of the total phosphorus content, or 41 kg ha^-1. The amount of total phosphorus was significantly higher near the inlet, compared to the outlet, which is explained by rapid sedimentation of particulate phosphorus entering the wetland. The phosphorus amount near the inlet represented 80 % of the total phosphorus load – which indicates the importance of internal circulation of phosphorus, both biological and geochemical. </span></p></div></td></tr></tbody></table></div>

With increasing water reuse applications and upcoming stringent regulations for treated wastewater effluent discharge, wastewater plants need to consider alternative technologies beyond conventional treatment processes. The new regulations, Numeric Nutrient Criteria (NNC), may regulate discharge nitrogen and phosphorus concentrations to as low as 0.5 mg/L as N and 10 μg/L as P respectively. To meet these target requirements, system retrofitting to incorporate chemical or advanced nutrient removal systems possibly with membrane technology will most likely be required. Although microfiltration/ultrafiltration membranes coupled with biological processes, otherwise known as membrane bioreactors (MBR), remove contaminants and suspended solids, nutrient removal is minimal to none. This emphasizes the importance of the biological process in MBRs. This study evaluated and tested the improvement of biological nutrient removal (BNR) in an MBR system which can meet NNC regulations along with the optimization of membrane operation for the reduction of fouling and energy consumption. A pilot study was conducted at the City of Tampa wastewater treatment plant and was divided into four phases of experimentation using two submerged MBR membranes operated with modified biological configurations. Laboratory analyses and data collection were conducted during the experiments and the performance evaluated for each configuration. System configurations were also optimized throughout each phase of testing for nutrient removal. Important factors used in the development of an appropriate configuration included isolation of the membrane tank from the biological reactors in the design, control of the dissolved oxygen (DO) concentrations or specifically the oxidation reduction potential (ORP) during operation and appropriate internal recirculation rates between the reactors. The results of this study provided information relevant for the assessment of both the BNR process and membrane performance. Membrane performance data indicated the importance and effect of air scouring (despite energy consumption) on membrane fouling for long-term stable flux operation as well as the cleaning frequency whether chemical enhanced backwash (CEB) or clean-in-place (CIP). This assessment also discussed how BNR systems can be enhanced through the incorporation of important design factors to eliminate the inhibiting factors of nitrogen and phosphorus removal such as dissolved oxygen. One of the biological processes tested in this study achieved effluent nitrogen and phosphorus concentrations below 5 mg/L and 1 mg/L respectively. Although the process tested did not meet NNC criteria, it can be applied with chemical precipitation. This, in turn, can reduce the operating and maintenance (O&M) costs associated with the chemical precipitation of phosphorus.

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Submitted by YEMALL ALEXANDER MAIGUAL ENRIQUEZ (alex.feisunesp@gmail.com) on 2018-05-08T00:18:49Z No. of bitstreams: 1 TESE MBBR-ICT-7-MAY-2018.pdf: 5856438 bytes, checksum: f1c36146463af4ee146d48da7c3be308 (MD5) / Approved for entry into archive by Bruna Bacalgini null (bruna@sorocaba.unesp.br) on 2018-05-08T14:17:18Z (GMT) No. of bitstreams: 1 enriquez_yam_dr_soro.pdf: 5856438 bytes, checksum: f1c36146463af4ee146d48da7c3be308 (MD5) / Made available in DSpace on 2018-05-08T14:17:18Z (GMT). No. of bitstreams: 1 enriquez_yam_dr_soro.pdf: 5856438 bytes, checksum: f1c36146463af4ee146d48da7c3be308 (MD5) Previous issue date: 2018-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A aquicultura é uma atividade de produção de espécies hidrobiológicas sob condições controladas. Esta atividade tem evoluído nos processos produtivos, mas estão gerando águas residuárias, quando lançadas diretamente nos corpos de água constituindo riscos potenciais à saúde. O reator de leito móvel com biofilme (MBBR) é uma variação do processo de lodos ativados. É um sistema de tratamento de efluentes que contem biofilme que cresce aderida aos suportes, que se movem livremente no volume do reator. O objetivo desta pesquisa foi determinar a eficiência na remoção de material, nitrogenado no MBBR dos efluentes gerados num sistema de recirculação para aquicultura “SRA”. O sistema MBBR com circulação (SC) - e com aeração (SA) obteve remoções medias de 38,7% para Nitrogênio Total Kjedahl (NTK), 28,9% de fósforo total, 44,5% de DBO, Nitrogênio Amoniacal Total (NAT) de 40% e 38,9% para amônia não ionizada e para nitrito foi 59,3%. Os sólidos Totais (ST), Sólidos Suspensos Totais (SST) e Sólidos Voláteis Totais (SVT) tiveram remoções de 28,0%, 45,9% e 57,4% respectivamente. Durante o período avaliado houve aumento do biofilme nos dois reatores. No MBBR-SA foi verificada a presença de protozoários, microinvertebrados e estruturas filamentosas semelhantes a estreptococos. No MBBR-SC, bactérias na forma de cocos, diplococos e estreptococos. Nas analises realizadas com MEV nos lodos dos dois sistemas foi encontrado traços de silício, alumínio, zinco, fósforo, sódio e magnésio. Também foi encontrado bactérias do tipo vibrio spp, bacilus spp, além da formação de aglomerados. As analises térmicas feitas nos lodos indicaram que houve perda de umidade até os 150°C. A maior parte da massa se perde entre 220°C e 580°C, faixa onde sofrem transformação térmica as proteínas, lipídeos, carboidratos, ácidos graxos, restos de paredes celulares bacterianas. Após os 600°C existe o restante, as cinzas são compostas por carbonatos e outros minerais transformando-se em matérias cristalinos, com baixa variação na massa. / Aquaculture is an activity of production of hydrobiological species under controlled conditions. These activities have evolved in the productive processes, but are producing wastewater, when thrown directly into bodies of water constituting potential health risks. The moving bed biofilm reactor (MBBR) is a variation of the activated sludge process. It is an effluent treatment system containing biofilm growing attached to the carriers, which move freely in the reactor volume. The aim of this research was to determine the efficiency in the removal of nitrogenous compounds in MBBR from the effluents generated in a recirculating aquaculture system "RAS". The MBBR system with circulation (CS) - and with aeration (AS) obtained mean removals of 38.7% for NTK, 28.9% of total phosphorus, 44.5% of BOD, 40% TAN and 38.9% for non-ionized ammonia and for nitrite was 59.3%. Total Solids (TS), Total Suspended Solids (TSS) and Total Volatile Solids (TSV) had removals of 28.0%, 45.9% and 57.4% respectively. During the evaluated period there was an increase of biofilm in the two reactors. In the MBBR-AS the presence of protozoa, microinvertebrates and filamentous structures similar to streptococcus was verified. Also, in MBBR-CS was verified coccus, diplococcus and streptococcus bacteria. In the analyzes performed with SEM in the sludge of the two systems, traces of silicon, aluminum, zinc, phosphorus, sodium and magnesium. Vibrio and bacillus type bacteria were present and besides granule formation. Thermal analyzes indicated that there was in the sludge moisture loss until 150°C. Most of the mass is loss between 220°C and 580°C, where they undergo thermal transformation of proteins, lipids, carbohydrates, fatty acids, remains of bacterial cell walls. After the 600°C the ashes are composed of carbonates and other minerals transforming into crystalline materials, with low mass variation. / CAPES: 12616-13-3

Purifying silicon to a certain degree is needed in the photovoltaic industry. In the metallurgical route, phosphorus is removed from molten silicon in an induction vacuum refining furnace.This study presents the simulation of the silicon dephosphorization process that takes into account a neglected factor thus far, namely the residual oxygen amount.A thermodynamic assessment is performed for the Si - P system, and the phosphorus solubility in silicon is determined. Resulting activity coefficients are incorporated in an algorithm created to simulate this phenomenon. By also using other literature data, this program predicts the distillation time of a n-type silicon sample as well as its weight loss as a function of the oxygen pressure in the enclosure.The experimental validation of those results is intended with an electromagnetic levitation device. It enables to melt a silicon sample without any contaminant crucible and under a controlled atmosphere. / La purification du silicium à un certain degré est requis pour l'industrie photovoltaïque. Par voie métallurgique, le phosphore est éliminé du silicium fondu dans un four à induction sous vide.Cette étude présente la simulation du processus de déphosphoration du silicium en prenant en compte un facteur jusqu'alors négligé, à savoir la présence d'oxygène résiduel.Un travail d'optimisation thermodynamique du système Si - P est effectué, où la solubilité du phosphore dans le silicium est notamment déterminée. Les coefficients d'activité qui découlent de celle-ci sont incorporés dans un algorithme créé pour simuler ce phénomène. En s'appuyant également sur des données issues de la littérature, ce programme prédit le temps de distillation d'un échantillon de silicium de type n ainsi que sa perte de masse en fonction de la pression d'oxygène dans l'enceinte.La validation expérimentale de ces résultats est envisagée en utilisant un dispositif de lévitation électromagnétique. Il permet de faire fondre un échantillon de silicium sans creuset contaminant et avec une atmosphère contrôlée.

Private wastewater treatment facilities release tons of phosphorus to the aquatic environment due to the insufficient removal efficiency in conventional soil infiltration systems. Reactive filter materials have demonstrated promising P removal rates. Laboratory-scale column experiments were carried out using Absol® and Polonite® in dual infiltration media and results were compared with Polonite® functioning as the only layer of reactive filter material. Two sets of experiments were arranged with layer lengths of 5 cm and 15 cm which were operated for 50 and 119 days respectively. Columns with an additional layer of Absol® demonstrated very good average removal rates of 85.99 % and 99.13 % in both experiments while the effluent in the former exceeded the maximum allowed P concentration shortly after half of the total time of the experiment. On the other hand, O-P concentration in collected samples from dual filter media with 15 cm layers of Absol® and Polonite® (column B1) was as low as 0.04 mg/l after 119 days of operation exhibiting high potentials for Absol® in local wastewater treatment. Levels of pH in treated samples showed a decreasing trend in all columns which was similarly simultaneous with high removal rates observed in B1.

The purpose of this study is to evaluate the convenience and effectiveness of using a disc filter to treat washing water from the sand filters at Sundet wastewater treatment plant. The disc filter is used aiming for the reduction of suspended solids and phosphorus. The study was divided in two main experimental stages. During the first stage laboratory jar-tests were performed in order to identify which flocculation aid was more suitable, this was further on used to improve the water treatment. Based on the laboratory trials results, two different polymers (1 and 2) were chosen to be tested at pilot scale. The second stage involved the pilot filter operation itself; this period was as well divided in two sub-stages where filter cloths with two different pore openings were tested. During the first sub-stage the pilot operated with an 18 μm pore opening filters cloth and both polymers. At the end of the first half polymer 1 showed to be more efficient and so it was further used throughout the second sub-stage in combination with a 10μm pore opening filter cloth. As from theoretical knowledge the phosphorus and suspended solid removal were expected to be between 75% and 90%, results which were achieved during both laboratory trials and pilot filter. The best results were observed with the 10μm pore opening filter cloth and polymer 1. Also, additional results from pilot trials performed at Sundet after the study period are presented.

The laboratory-scale University of Cape Town (UCT) process was designed to investigate the effects of changing COD/TP ratios on the performance of biological nutrient removal (BNR) processes. Specific objectives of the research were to investigate the effects of COD/TP ratio on the rates of phosphorus removal, COD removal, nitrogen removal, PHB utilization and oxygen uptake. The system was fed with municipal wastewater and operated at 20° C. The influent COD concentration was held approximately constant while the phosphorus concentration was varied to obtained the desired COD/TP ratio. Once robust enhanced biological phosphorus removal (EBPR) has been established, the COD/TP ratios of 20, 30, 40 and 60 were investigated. The COD/TP ratio of the influent wastewater was observed to have a substantial effect upon the performance of the UCT BNR system. The amount of phosphorus removed by the system and the percent phosphorus in the aerobic zone MLVSS decreased as the COD/TP ratio increased. In addition, the amount of phosphorus released in the anaerobic zone per unit of COD removed in the anaerobic zone increased as the COD/TP ratio decreased. From this research, the amount of anaerobic COD removal required to remove 1 mg/L of phosphorus in the aerobic zone approached a minimum value as the COD/TP ratio decreased. It was also shown that PHB production increased as the COD/TP ratio increased. The highest specific oxygen uptake rate was always observed in the second aerobic reactor and tended to increase as the COD/TP ratio increased. However, the changes in the COD/TP ratio did not significant affect COD removal, nitrogen removal and the observed yield coefficient, but did strongly affect the MLSS concentration. The MLSS concentration at the COD/TP ratio of 60 was only 55% of that at the COD/TP ratio of 20. A high level of anaerobic COD removal, an elevated percent phosphorus in the waste activated sludge (WAS) and a high soluble effluent phosphorus concentration can be used as indicators that the system is operating under COD limiting conditions. Several phenomena were also observed during this research. Firstly, the performance of the UCT BNR system for EBPR was greatly enhanced by reducing the aerobic volume. Secondly, the correlation between non-oxic phosphorus release and the aerobic phosphorus uptake improved when anoxic phosphorus release was taking into consideration. This indicated that the anoxic phosphorus release was not secondary release once the aerobic zone volume was reduced. Finally, no denitrification was observed in the aerobic zone from this study, based on the assumption that 12% of nitrogen was required for bacterial growth. / Master of Science