Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Embora todas as etapas do processo de produÃÃo de biodiesel a partir de microalgas sejam essenciais, a separaÃÃo e a ruptura celular da biomassa sÃo particularmente importantes, uma vez que as tecnologias disponÃveis para este fim apresentam elevados custos, comprometendo a viabilidade do aproveitamento energÃtico. Este trabalho teve como objetivo apontar um sistema que conseguisse aliar a separaÃÃo da biomassa algal de efluente de sistemas de lagoas de estabilizaÃÃo à ruptura celular, como uma alternativa de prÃ-tratamento para maximizar a extraÃÃo de lipÃdios pelo mÃtodo modificado de Bligh e Dyer; assim como estudar preliminarmente a comunidade fitoplanctÃnica presente para comparaÃÃo dos rendimentos lipÃdicos. Um reator de eletroflotaÃÃo nÃo-convencional foi confeccionado para operar em batelada e em fluxo contÃnuo, utilizando-se eletrodos nÃo consumÃveis e baixa potÃncia elÃtrica. A metodologia proposta foi comparada com tÃcnicas tradicionalmente utilizadas para ruptura celular: autoclave, micro-ondas e ultrassom. Foram selecionadas seis estaÃÃes de tratamento de esgotos (ETE) com diferentes configuraÃÃes de lagoas de estabilizaÃÃo para anÃlise dos gÃneros fitoplanctÃnicos dominantes e do teor lipÃdico. Observou-se a separaÃÃo da biomassa, sendo obtida eficiÃncia de remoÃÃo de turbidez superior a 80% em 20 minutos de operaÃÃo do reator em batelada. Entre os mÃtodos de prÃ-tratamento tradicionais testados, o micro-ondas foi o que apresentou maior rendimento lipÃdico (33,7  5,3%), diferente estatisticamente da autoclave (15,4  2,26%) e ultrassom (13,3  2,96%). Para a eletroflotaÃÃo nÃo-convencional o rendimento lipÃdico foi de 24,8  7,05%, que nÃo apresentou diferenÃa estatÃstica quando comparado ao micro-ondas. Entretanto, quando os custos energÃticos foram considerados, a eletroflotaÃÃo nÃoconvencional apresentou um custo de 5,6 Wh.g-1, sendo menor que o obtido para o micro-ondas. Os gÃneros de microalgas que predominaram nos efluentes analisados pertenciam Ãs classes Chlorophyceae, Cyanophyceae e Euglenophyceae. Em uma anÃlise quantitativa geral, os efluentes de todas as estaÃÃes analisadas apresentaram rendimento lipÃdico entre 8,5 e 34,6%. Os efluentes das ETE Aquiraz e TupÃ-Mirim apresentaram os maiores teores lipÃdicos (28,4  6,3% e 23,1  3,6%, respectivamente), sem diferenÃa estatÃstica (p=0,12). Os efluentes das ETE Araturi e Tabapuà apresentaram os menores potenciais lipÃdicos, sem diferenÃa estatÃstica entre eles (14,3  5,9% e 15,6  4,9%, respectivamente, p=0,68). A eletroflotaÃÃo nÃo-convencional mostrou-se como uma metodologia promissora para separaÃÃo e ruptura das cÃlulas de microalgas de efluentes de lagoas de estabilizaÃÃo, cujos potenciais lipÃdicos assemelharam-se aos obtidos a partir de biomassa microalgal cultivada em processos convencionais. AlÃm disso, a metodologia desenvolvida neste trabalho soma um motivo para a separaÃÃo e utilizaÃÃo da biomassa algal de lagoas de estabilizaÃÃo evitando, com isso, seu lanÃamento nos corpos dÂÃgua e garantindo um ganho econÃmico e ambiental, uma vez que visa o aproveitamento da biomassa para a produÃÃo de biocombustÃvel, ao passo que minimiza impactos ambientais decorrentes da presenÃa elevada desse material no ambiente. / Although all stages on the production of biodiesel from microalgae cells are essential, harvest and cell disruption biomass are particularly important, since the available technologies for this purpose present high cost, compromising energy recovery viability. This study aimed to develop a system that could combine separation of algal biomass from wastewater stabilization pond systems to cell disruption as an alternative of pretreatment to maximize total lipids extraction by the modified method of Bligh and Dyer, as well as perform a preliminary study of the phytoplankton for comparison of lipid content. A non-conventional electroflotation reactor was designed to operate in batch and continuous flow, using non-consumable electrodes and low electrical power. The proposed methodology was compared to traditional techniques used for cell disruption: autoclave, microwave and ultrasound. Six Wastewater Treatment Plant (WTP) with different pond configuration were selected for analysis of the dominant phytoplankton genera and lipid content. Biomass separation was achieved, with turbidity removal efficiency exceeding 70% in 20 minutes of operation with the batch reactor. Among the traditional pretreatment methods tested, the microwave showed the highest lipid yield (33.7  5.3%), followed by autoclave (15.4  2.26%) and ultrasound (13.3  2.96%). For non-conventional electroflotation methodology, lipid yield was 24.8  7.05%, which showed no statistical difference when compared to the microwave method. However, when energy cost was considered, non-conventional electroflotation presented a cost of 5.6 Wh.g-1, which was smaller than that obtained by the microwave method. The predominant microalgae genera in the analyzed effluents belonged to the classes Chlorophyceae, Cyanophyceae and Euglenophyceae. In a general quantitative analysis, the effluents from the analyzed ponds presented lipid yield between 8.5 and 34.6%. Effluents of the WTP Aquiraz and TupÃ-Mirim achieved the highest lipid content (28.4  6.3% and 23.1  3.6%, respectively), with no statistical difference (p = 0.12). Effluents of the WTP Araturi and Tabapuà achieved the lowest lipidic potential, with no statistical difference (14.3  5.9% and 15.6  4.9%, respectively, p = 0.68). Non-conventional electroflotation proved to be a promising methodology for harvesting and cell disruption of microalgae provided by effluent stabilization ponds, whose potential lipid resembled those obtained from microalgal biomass cultivated in conventional processes. Furthermore, the methodology developed in this work adds a reason for the harvesting and utilization of algal biomass from waste stabilization ponds avoiding, thus, its release into water bodies and ensuring an environmental and economic gain, since it aims the use of biomass for biofuel production, while minimizing environmental impacts due to elevated presence of this material on the environment.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-11T18:56:39Z No. of bitstreams: 1 2014 - Bruno Botelho Saleh.pdf: 2346129 bytes, checksum: fe906738dca9a661de96e77fdb8c304a (MD5) / Made available in DSpace on 2017-05-11T18:56:39Z (GMT). No. of bitstreams: 1 2014 - Bruno Botelho Saleh.pdf: 2346129 bytes, checksum: fe906738dca9a661de96e77fdb8c304a (MD5) Previous issue date: 2014-07-17 / CAPES / The city of Rio Verde-GO has excelled for having important agro-industrial units with important breeding of cattle, poultry and pigs. The swine farms handle the liquid waste stabilization ponds with or without digesters systems, accumulating them for 2 months to 4 months, and then applied in areas of approximately 100 to 300 acres. Floating gas collection chambers, where the samples are captured biogas emitted to the atmosphere of stabilization ponds and then analyzed the samples in the laboratory of Embrapa Agrobiology were installed, in addition, to conduct sampling of swine manure (DLS) itself to quantification of elements present in it. It was found in this study that the largest emissions of methane (CH4) were in the following descending order of magnitude: 205.3 ? 68.79 Mg CH4 yr-1 for the fattening farm without biodigester (4,000 swines); 123.94 ? 39.17 Mg CH4 yr-1 in the fattening farm with a biodigester (4,000 swines); 11.22 ? 3.0 ton CH4 year-1 for the producing piglets farm with a biodigester (1,008 matrices swines) and 2.75 ? 0.89 Mg CH4 yr-1 in the producing piglets farm with two biodigesters (728 matrices swines), thus proving expected to their farms in production. Interaction in methane (CH4 Mg yr-1) and concentration (mg L-1) macronutrients (N, P and K) present in the DLS was observed for nitrogen (Ntotal) a linear equation y = 0.1797x ? 111.81 (R2 0.9844); for phosphorus (P) is the linear equation y = 1.4905x ? 25.224 (R2 0.9436); whereas for potassium (K) a linear equation y = 0.0693 ? 35.934 (R2 0.9337). / A cidade de Rio Verde-GO tem se destacado por contar com importantes unidades agroindustriais com importante plantel de bovinos, av?cola e de su?nos. As granjas de su?nos manejam os res?duos l?quidos em sistemas de lagoas de estabiliza??o com ou sem biodigestores, acumulando-os durante 2 meses a 4 meses, sendo ent?o aplicados em ?reas de aproximadamente 100 a 300 hectares. Foram instaladas c?maras flutuantes de coleta de gases, onde foram capturadas as amostras do biog?s emitido para atmosfera das lagoas de estabiliza??o e ent?o analisadas as amostras no laborat?rio da Embrapa Agrobiologia, al?m, da realiza??o de coletas de amostras do pr?prio dejeto l?quido de su?no (DLS) para quantifica??o dos elementos presentes no mesmo. Verificou-se na presente pesquisa que as maiores emiss?es de metano (CH4) ocorreram na seguinte ordem de grandeza decrescente: 205,3 ? 68,79 Mg CH4 ano-1 para a granja em termina??o sem biodigestor (4.000 su?nos); 123,94 ? 39,17 Mg CH4 ano-1 na granja de termina??o com um biodigestor (4.000 su?nos); 11,22 ? 3,0 Mg CH4 ano-1para a granja de produ??o de leit?es com um biodigestor (1.008 matrizes em produ??o) e 2,75 ? 0,89 Mg CH4 ano-1 na granja de produ??o de leit?es com dois biodigestores (728 matrizes em produ??o), comprovando assim o esperado para as respectivas granjas em produ??o. Na intera??o das emiss?es de metano (Mg CH4 ano-1) e a concentra??o (mg L-1) de macronutrientes (N, P e K) presentes nos DLS observou-se para o nitrog?nio (NTotal) uma equa??o linear ? = 0,1797? ? 111,81 (R2 de 0,9844); em rela??o ao f?sforo (P) esta equa??o linear ? = 1,4905? ? 25,224 (R2 de 0,9436); enquanto que para o pot?ssio (K) uma equa??o linear ? = 0,0693? ? 35,934 (R2 de 0,9337).

Com base no poder dos topônimos de conservar tradições é que neste trabalho pretende-se investigar e classificar os principais nomes de bairros, lagoas, morros, loteamentos que constituem o município de Imbituba -Santa Catarina- no intuito de elucidar suas perspectivas motivacionais designativas. São analisadas as 12 lagoas que compõem o município e os bairros que estão ao seu entorno, pois é através da análise dos nomes de lugar que se procura conhecer e interpretar as tradições e costumes dos homens que habitaram ou habitam em uma determinada região. Ao se fazer um estudo topônimo de uma localidade, procura-se compreender a própria mentalidade do denominador, não só como elemento isolado, mas como projeção de um grupo social. Na perspectiva de cumprir o objetivo geral do trabalho- estudar e analisar os diferentes topônimos dos bairros pesquisados- seguiu-se os passos da catalogação dos topônimos segundo o modelo taxionômico proposto por Dick (1992), que apresenta 27 (vinte e sete) categorias, distribuídas em taxionomias de natureza física (11 taxes) e taxionomias de natureza antropocultural (16 taxes), e com isso integrando-se num projeto maior, coordenado pela autora sob título Atlas Toponímico do Brasil (ATB). Portanto, ao desenvolver esse tema à luz da toponímia, justifica-se o seu caráter integral e interdisciplinar, o que possibilita o estudo de uma determinada realidade social, desvendando sua cultura, seus hábitos e seus interesses. / Based on the influence of toponimic names to preserve the traditions, the aim of this work was to investigate and classify the major names of neighborhoods, lakes, hills, lots that compose the municipality of Imbituba, Santa Catarina, in-order to elucidate their designative motivational perspectives. Twelve lakes that make up the city were analyzed and the neighborhoods that are at its surroundings, since it is through the analysis of \"place names\" that it is possible to understand and interpret the traditions and customs of men who lived or live in a particular region. When making a study of a toponimic location, the very mentality of the denominator can be understood, not only as an isolated element but as a projection of a social group. Aiming the overall objective of the work - study and analysis of different place names of the surveyed districts - the footsteps of cataloging the taxonomic place names along the lines proposed by Dick (1992) have been followed. Dicks work has 27 (twenty seven) categories, distributed in taxonomies of physical nature (11 taxes) and taxonomies of anthropo-cultural nature (16 taxes), and are integrated into a larger project, coordinated by the author named Brazilian Toponymic Atlas (BTA). As a result in developing this issue, \"at the light of toponymy\", its integral and interdisciplinary nature is justified, what enables the study of a particular social reality, unveiling its culture, habits and interests.

Rapid increases in air temperature in Arctic and subarctic regions are driving significant changes to surface water. These changes and their impacts are not well understood in sensitive high Arctic ecosystems. This thesis explores changes in surface water in the high Arctic pond complexes of western Banks Island, Northwest Territories, and examines the impacts of this change on vegetation communities. Landsat imagery (1985-2015) was used to detect trends in surface water, moisture, and vegetation productivity, aerial imagery change detection (1958 and 2014) quantified shifts in the size and distribution of waterbodies, and field sampling investigated factors contributing to observed changes. The impact of expanding lesser snow goose populations on observed changes in surface water was investigated using the aerial imagery change detection of 2409 waterbodies and an information theoretic model selection approach, while their impact on vegetation was assessed using data from field surveys. Our analyses show that the pond complexes of western Banks Island are drying, having lost 7.9% of the surface water that existed in 1985. This loss of surface water disproportionately occurred in smaller sized waterbodies, indicating that climate is the main driver. Model selection showed that intensive occupation of lesser snow geese was associated with more extensive drying and draining of waterbodies and suggests this intensive habitat use may reduce the resilience of pond complexes to climate warming. Evidence from field surveys suggests that snow goose foraging is also contributing to patches of declining vegetation productivity within drying wetland areas. Diminishing and degrading high Arctic pond complexes are likely to alter permafrost thaw and greenhouse gas emissions, as well as the habitat quality of these ecosystems. Additional studies focused the mechanisms of surface water loss, the direct impacts of wetland drying on vegetation, and the contributions of snow geese to these processes, are necessary to better understand the changes occurring on Banks Island. / Graduate

Beaver dams alter streams characteristics in a way that promotes the diversity of aquatic species and provides a wide distribution of temperatures within beaver ponds. In order to quantify the spatial distribution of these temperatures, a process-based temperature model was developed for a beaver pond in Northern Utah. This model provided insight into the processes and characteristics that are driving these temperatures. Solar radiation is one of these processes that is often the primary driver of stream temperature. There is a need to develop methods to measure the fate of solar radiation within the water to better represent solar radiation within stream temperature models. Black-body pyranometers are instruments that measure solar radiation in air, but require corrections for use underwater. Studies were conducted investigating methods for correcting these instruments. Based on the results of these studies it is suggested that these corrections are dependent on the spectrum of the light source and that the instrument needs further corrections when the light source is measured from different angles; therefore there is a need for further investigation into pyranometer corrections in order to measure the fate of solar radiation in natural water bodies. Combined, this research provides methods and suggests additional research opportunities for more accurately quantifying and predicting stream temperatures for waters impacted by beaver.

Beavers were virtually extirpated from North America during the fur trade, but populations have since recovered. Dams built by recolonizing beaver alter stream habitat by forming deep, slow ponds within the streams. Such changes to the habitat is likely to have consequences for organisms such as macroinvertebrates and fish. The objective of this study was to identify the differences in the macroinvertebrate and trout community in beaver ponds and lotic (e.g. flowing reaches of a stream) reaches in tributaries to the Logan River in northeastern Utah. The macroinvertebrate community of beaver ponds had fewer species, fewer numbers, and lower biomass of macroinvertebrates compared to lotic reaches. Macroinvertebrates that consume leaf litter and predators that prey on other macroinvertebrates characterized beaver pond macroinvertebrate communities. In contrast, lotic reaches contained macroinvertebrates that consume algae and feed on particles floating through the water column. Macroinvertebrates in lotic reaches were morphologically adapted to cling to rocks in the streamflow, while those in beaver ponds were adapted to living within the fine sediment. Bonneville cutthroat trout collected from lotic reaches were larger than those collected from beaver ponds, while the opposite was true for brown trout collected from lotic reaches. I also found that short-term and long-term diets of both brown trout and Bonneville cutthroat trout were similar between trout caught in beaver pond and lotic reaches. Finally, I found that growth rates of trout were also similar between the two habitats. In conclusion, the structure and function of macroinvertebrates, which are dependent on small-scale habitat features, were more affected by inclusion of beaver ponds to the stream network. Conversely, trout collected from beaver ponds and lotic regions were similar in growth and diet. Considering that beavers are used as a common restoration tool, further studies on the effects of beaver on stream communities is essential.

Cattle farming is vital to the economy of the United States. Frequently, cattle are given access to ponds and streams for water. The relative impacts of cattle access in natural water sources on the periphyton community have been rarely investigated. Periphyton is the basis of the aquatic food web, and community composition can serve as a bioindicator of pollution. Thus, my objectives were to quantify the effects of cattle access in aquatic lentic systems on periphyton community structure and biovolume, identify taxa that were associated with cattle access, and identify abiotic mechanisms that might be driving assemblage changes. I conducted my research in 4 cattle-access (CA) and 4 no-access (NA) farm ponds on the University of Tennessee Plateau Research and Education Center from May 2005 – April 2006. Periphyton community composition and water quality were measured every 2 weeks using standard environmental monitoring procedures. I documented 181 new periphyton taxonomic records (7 phyla, 52 families, and 132 genera) in Cumberland County, Tennessee. Periphyton species richness was greatest in NA ponds. Mean biovolume of pollution-sensitive diatoms (e.g., Achnanthidium minutissimum, Cymbella sp., Eunotia sp., Fragilaria crotonensis and Tabellaria fenestrata) was greater in NA ponds. In contrast, pollution-tolerant diatoms (e.g., Gomphonema sp. and Navicula sp.) and non-diatoms (e.g., Oscillatoria sp. and Scenedesmus sp.) were more abundant in CA ponds. Turbidity, pH, conductivity, and concentrations of the total Kjeldahl nitrogen, total phosphorus, potassium, periphyton phosphorus, silicon, iron, magnesium and aluminum were greater in CA ponds. Thus, changes in water quality associated with cattle-access likely mediated changes in the periphyton community. Considering that changes in periphyton community composition can destabilize higher trophic levels, I recommend that cattle farmers take advantage of USDA conservation programs that provide funds for fencing cattle from watersheds and developing alternate water sources. My results also provide evidence that monitoring the periphyton community is a reliable technique to detect water pollution from cattle.

This investigation explored the use of microcosms as a tool for studying the dynamics of tropical aquaculture ponds. The potential use of rabbit excreta as a pond fertilizer in integrated farming systems was also investigated. Twelve insulated fiber glass tanks were utilized as microcosms to simulate earthen ponds. Seven hand-sexed Nile Tilapia O. niloticus) were stocked per tank, and microcosm performance was observed for a 90- day experimental period. Three rabbit excreta loading rates corresponding to 50 and 75 kg/10,000 m³ /day, and a continuously adjusted manure loading rate were assessed. The fertilizer treatments were compared to a control treatment where fish were fed on a prepared food. Water quality variables and fish performance were regularly monitored. Nitrogen and phosphorous content of rabbit excreta were measured. The dynamics of the microcosms were similar to warm water earthen ponds with respect to physical and chemical characteristics. Statistical differences were detected between control and fertilized treatments in relation to dissolved oxygen levels, net primary productivity, total alkalinity, total ammonia and orthophosphate levels. Primary productivity was influenced more by light intensity and penetration than by nutrient limitation. Rabbit excreta overloading was observed in the 75 kg treatment. Fish growth was greatest in the control treatment, but it was not statistically different from the continuously adjusted fertilizer treatment (Pondclass) (0.0065 and 0.0056, respectively). Low daily fish gains were observed in the 50 and 75 kg treatments. Low dissolved oxygen and high total ammonia were concentrations resulted in low weight gains and condition indices of fish in the 50 and 75 kg treatments. Extrapolated fish yields corresponded to 6,205, 4,563, 3,686, 4,869 kg/ha/year for control, 50 kg, 75 kg and Pondclass treatments, respectively. The observed yields are comparable with field experiences in real ponds. The continuously adjusted treatment showed the lowest manure conversion ratio (3.85) in the fertilized treatments. The nitrogen content of rabbit excreta varied according to rabbit size, presence or absence of urine plus water waste, and food droppings. Urine plus water waste provided 28 % of the total nitrogen content in rabbit excreta, whereas food droppings provided 12 %. Rabbit urine may play an important role in aquacultural systems because it contains a large fraction of nitrogen in inorganic forms which are readily utilized for algal growth. Other rabbit excreta characteristics such as buoyancy may be advantageous in aquacultural systems. Rabbit excreta is a potentially rich source of fertilizer for use in fish ponds. / Graduation date: 1992

Freshwater ostracods (crustacea, ostracoda) are sensitive to environmental conditions, and are widely used as biological indicators for past and present environmental changes. The abundance and diversity of ostracods from permafrost areas is currently documented in scattered records with incomplete ecological characterizations. The objectives of the thesis were to determine the taxonomic and ecological range of ostracod assemblages and their habitat conditions in polygon ponds in different landscape units of the Indigirka Lowland (north-east Siberia, Russia). A monitoring approach focused seasonal meteorological and limnological variability of a selected pond site, its ostracod population dynamics, and the geochemical properties of ostracod valve calcite. Shallow, well-oxygenated, and dilute ponds with slightly acidic to circumneutral pH hosted an abundant and diverse ostracod fauna. A total of 4849 identified ostracods from eight species and three taxa represent the first record of the ostracod fauna in the Indigirka Lowland. Fabaeformiscandona krochini and Fabaeformiscandona groenlandica were documented for the first time in continental Siberia. Fabaeformiscandona sp. I and Fabaeformiscandona sp. II were newly found taxa holding a strong indicative potential for hydrochemical parameters. Repeated sampling of a typical low-center polygon pond revealed detailed insights in the population dynamics of Fabaeformiscandona pedata and its reproduction strategy. Substrate properties, physical and hydrochemical conditions in the studied ponds offered largely homogeneous habitats across different landscape units and pond types to ostracods. River flooding and differences in morphology between pond types resulted in variations in sediment, vegetation, hydrochemical and stable water isotope composition of the ponds. Ponds in the river floodplain and intrapolygon ponds hosted the most diverse ostracod fauna while species diversity was lowest in thaw lakes. Air temperature and precipitation were identified as the main external drivers of water temperatures, water levels, ion concentrations, and stable water isotope composition in small periglacial waters on diurnal and seasonal scales. Ostracod valve calcite recorded seasonal variations in stable oxygen isotopes of the ambient waters, but needs to be interpreted carefully with regard to species-specific background knowledge. / POLYGON - Polygons in tundra wetlands: state and dynamics under climate variability in polar regions

<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>