Orientador: Tsunao Matsumoto / Banca: Dib Gebara / Banca: Rodrigo Braga Moruzzi / Resumo: No Brasil, existe um problema comum à maioria das comunidades onde o abastecimento público de água é realizado com água superficial e há a necessidade de tratamento. No processo de tratamento ocorre a formação de resíduos na forma de lodo, o qual periodicamente necessita ser descartado do processo. Exceção feita a algumas Estações de Tratamento de Água (ETA), em nível nacional, todas despejam esses resíduos, de forma bruta, sem nenhum tratamento, em corpos de água. O presente trabalho foi realizado com o objetivo de encontrar solução adequada para destinar, de forma correta, o lodo produzido pela ETA da cidade de Presidente Prudente, operada pela Companhia de Saneamento Básico do Estado de São Paulo (SABESP). O estudo baseou-se na premissa em aplicar o lodo da ETA na Estação de Tratamento de Esgotos (ETE), no adensador por gravidade existente. E, para tanto, foi montada uma ETE Piloto, com a qual foram realizadas as simulações de aplicação de cargas de 2000 mg/L e 4000 mg/L de lodo de ETA A avaliação do desempenho da unidade piloto foi conseguida por meio de monitoramento analítico de parâmetros como: pH, temperatura, oxigênio dissolvido, alcalinidade, DBO, DQO, Fósforo, Nitrogênio, sólidos dissolvidos, totais, fixos e voláteis, turbidez, Índice Volumétrico de Lodo (IVL) e Teor de Lodo (TL). Os resultados mostraram que a carga de 2000 mg/L de lodo de ETA no adensador por gravidade, pode ser realizada sem causar problemas. No entanto, com carga de 4000 mg/L, constatou que as aplicações progressivas de lodo devem ser melhor pesquisadas / Abstract: In Brazil, very common problem to the biggest part of the communities, where the public water supply is realized using the surface water, and needs to pass by the water treatment plant (WTP). In the treatment process, a residue formation in the form of sludge occurs, which periodically needs to be discarded out the process. Except some WTP, on a nation level all they discarded these residues, in brutal way and without treatment, in watercourses. In this work was realized with the objective to finding an adequate solution to properly allocate the sludge produced in the Water Treatment Plant (WTP) from Presidente Prudente, which is operated by SABESP. This study was based in premise to apply the WTP sludge in the Wastewater Treatment Plant (WWTP), in the thickener by an existing gravity. And however, it was built a WWTP Pilot plant where were realized the simulations of applying dosages of 2000 mg/L and 4000 mg/L of WTP sludge. The evaluation of the performance of the pilot unit was gotten by analytical monitoring of many parameters as: pH, temperature, dissolved oxygen, alkalinity, BOD, COD, phosphorus, nitrogen, dissolved solids, fixed and volatile ones, turbidity, Sludge Volumetric Index (IVL) and sludge concentration (TL). The results showed that the application of 2000 mg/l of WTP sludge in the WWTP gravity thickener can be realized without problems. On the other hand the application of 4000 mg/l showed that progressive applications of sludge have to be better researched / Mestre

Made available in DSpace on 2014-07-29T15:01:47Z (GMT). No. of bitstreams: 1 Dissertacao _Leonora Milagre de Souza.pdf: 965865 bytes, checksum: e8839b11b69dccbdd9fd61b7554b691b (MD5) Previous issue date: 2011-06-21 / The residue generated in Water Treatment Plant (WTP) are derived from different stages of water treatment, especially the discharge of decanters. The most common practice in Brazil is the residue disposal directly into rivers, causing negative impacts to the environment. In general, the WTP have difficulties in managing the residue because the high costs of transportation and disposal, the steady increase in the consumption of chemicals, among other complicating factors. Aiming to reduce the coagulant used in the process and improving the characteristics of the residues for the outflow, this research examined the effects of biosolids application decanter of WTP in the processes of coagulation, flocculation and sedimentation of water treatment. Through laboratory tests, using Jar Test, there were three series of tests, each one using gross water with distinct turbidity. In these trials were used differents dosages of aluminum sulfate and applied to WTP samples with different concentrations of total solids suspended (TSS). After the Jar Test, the decanted water was characterized as turbidity and color, solids and coliforms were not found significant changes in their quality. For most situations, the residue application in treatment has reduced the coagulant in the range 50% to 60%. The increased turbidity of gross water allowed the application of more concentrated residue without reducing the efficiency of treatment in terms of turbidity removal. Regarding the sedimented material in the Jar Test, the decreasing of the dosage of coagulant favored the reduction of the occupied volume by the material, independent of the concentration of residue applied. The specific resistance of sedimented material was higher when compared to the situation without the application in virtually all studied situations. For water with 100 NTU and implementation of residue greater than 7.500 mg/L, and water with 210 NTU and residue less than 8.600 mg/L there was improvement in the sedimentability. The dewatering ability of the sediments by centrifugation was also improved with the application of the residue with 3.642 mg/L and 75% of the coagulant, and 7.500 mg/L using 50% of coagulant. The chemical conditioning by nonionic polyelectrolyte did not improved in the dewatering of sedimented material, but in improving water quality supernatant. Based on this study it was noticed that the application of WTP residue in water treatment was satisfactory as for the analyzed parameters, considering the dosage of coagulant used and the residue applied. / Os resíduos gerados nas Estações de Tratamento de Água (ETAs) são decorrentes das diversas etapas do tratamento da água, em especial da descarga de decantadores. A prática mais comum no Brasil de disposição desse resíduo é diretamente em corpos hídricos, podendo causar impactos negativos ao meio ambiente. Em geral, as ETAs apresentam dificuldades no gerenciamento dos resíduos devido os altos custos com transporte e disposição, o aumento constante no consumo de produtos químicos, dentre outros complicadores. Visando a redução de coagulante utilizado no processo e a melhoria das características desse resíduo para o deságue, a presente pesquisa analisou os efeitos da aplicação do resíduo de decantador de Estação de Tratamento de ETA (ETA) nos processos de coagulação, floculação e sedimentação do tratamento de água. Por meio de ensaios laboratoriais, utilizando Jar Test, foram realizadas três séries de ensaios, cada uma utilizando água bruta com turbidez distinta. Nesses ensaios foram empregadas dosagens variadas de sulfato de alumínio e aplicadas amostras de resíduo da ETA com concentrações de sólidos suspensos totais (SST) diferentes. Após a realização dos ensaios de Jar Test, a água decantada foi caracterizada quanto à turbidez, cor aparente, concentração de sólidos e coliformes, não sendo verificadas alterações significativas em sua qualidade. Para a maioria das situações, a aplicação do resíduo no tratamento possibilitou a redução de coagulante na faixa de 50% a 60%. O aumento da turbidez da água bruta permitiu a aplicação do resíduo mais concentrado, sem reduzir a eficiência do tratamento quanto a remoção de turbidez. Com relação ao material sedimentado gerado nos ensaios de Jar Test, a redução da dosagem de coagulante favoreceu a redução do volume ocupado pelo material, independente da concentração de resíduo aplicado. A resistência específica do material sedimentado foi maior se comparada à situação sem aplicação do resíduo, em praticamente todas as situações estudadas. Para a água com 100 UNT e aplicação do resíduo maior que 7.500 mg/L, e água com 210 UNT e resíduo menor que 8.600 mg/L houve melhora na sedimentabilidade. O deságue do material sedimentado por meio de centrifugação também melhorou com a aplicação dos resíduos com 3.642 mg/L e 75% de coagulante, e 7.500 mg/L utilizando 50% de coagulante. O condicionamento químico por meio de polieletrólito não iônico não auxiliou no desaguamento do material sedimentado, e sim na melhoria da qualidade da água sobrenadante. Baseado neste estudo percebeu-se que a aplicação do resíduo da ETA no tratamento de água foi satisfatória quanto aos parâmetros analisados, devendo ser levada em consideração a dosagem de coagulante empregada e a concentração do resíduo aplicado.

This thesis contributes to the currently still sprawling literature on the force of sustainable investing together with the “Big Five” personality structure (Openness to Experience, Conscientiousness, Extraversion, Agreeableness and Neuroticism). By investigating which personality trait, based on the Big Five personality taxonomy, that was willing to exchange revenue for a higher ESG rating in a hypothetical investment fund, we were able to determine when private investors were willing to pay more for a more sustainable investment. We use new data from our own questionnaire where the respondents are adult individuals residing in Sweden who has invested in the stock market. The data was analyzed with an econometric approach and for the regression ordinary least square and tobit was used. The results revealed that two personality traits (conscientiousness and agreeableness) tended to be less interested in sustainable investments, as they were not willing to pay for a fund with a higher ESG rating, unlike Openness to Experience, where the willingness to pay was high. The other two traits also showed a positive relationship and thus willingness to trade revenue for sustainability. This thesis contributes to the knowledge on how the personality of the private investors can motivate investment decisions and the preference of companies they invest in.

Master's thesis deal with the design and static analysis of supporting structures of main underground reinforced concrete tank located in Combined cast-in-place structure of WTP in Kořenec. The tank has dimensions of 9.5 x 9.5 m and the is divided into four sub-tanks by internal walls. Supporting structures, foundation slab, external and internal walls and ceiling slab, were verified for limit state design requirements for concrete members. Verification of serviceability limit state and crack control of width was made.

<p>Chapter 1: Currently there is no hunting or trapping season on bobcats in Indiana. While a season is being considered by wildlife administrators, there is no basis for establishing a price or understanding potential demand for this species. We use contingent valuation to estimate furbearer hunter and trapper willingness-to-pay (WTP) for a hypothetical bobcat harvest permit in Indiana, USA. Using a mail survey of 2000 randomly selected Indiana registered hunters and trappers, we presented respondents with a description of a hypothetical harvest season, including season dates, equipment restrictions, check-in procedures, counties open for the legal harvest, bag limit (the number of animals that can be legally harvested per individual), and statewide quota (the number of animals that can be legally harvested in aggregate). Following the description, respondents were asked a single-bounded dichotomous choice question about purchasing the proposed permit. By applying the Turnbull estimation method to our collected data, we estimate mean WTP of $21.73 for the proposed permit. Our estimates are sensitive to scope effects, which may be linked to perceived congestion: if hunters believe the bag limit may not be filled, WTP may actually decrease with the bag limit due to perceived congestion, necessitating the simultaneous examination of the bag limit and statewide quota.</p> <p><br></p> <p>Chapter 2: One Health initiatives employed by the Centers for Disease Control and Prevention place emphasis on the interconnectedness of animals, people, plants, and the environment. As new disease threats emerge, the interactions of humans and animals with their environments becomes increasingly important. Deer represent a large, prolific, and suitable host for several diseases that are potentially threatening in the One Health context. Previous works have studied deer-related diseases, such as Bovine tuberculosis and Lyme Disease, and examined risks of transmission in households of varying compositions, such as with and without pets or children. However, research quantifying public perceptions of deer and their role(s) in modern society is lacking. Our research applies social media listening to study perceptions of deer among the general U.S. population through volume (number of mentions) and assessment of tone, in terms of positivity versus negativity (analyzed as online media net sentiment). We study media about five prominent deer-related diseases from January 2018 through December 2021 and demonstrate that while aggregate mentions of the deer diseases we study compose a small proportion of total mentions for deer, net sentiment surrounding outbreaks reflects the seriousness of the health consequences these present. Additionally, we explain fluctuations in deer-disease mentions and net sentiment through real-world events, and demonstrate seasonality in mentions and net sentiment for some diseases of interest. Better understanding of public perceptions of the roles of wildlife, particularly deer who are generally perceived as non-threatening wildlife, is particularly important in today’s One Health context.</p> <p><br></p> <p>Chapter 3: The presence of deer in shared environments with humans may result in both positive and negative affinity towards deer. While literature shows deer-related damages to humans and their property, literature also suggests that deer are a way for humans to connect with nature. Managing deer populations is vital to balancing the positive and negative impacts of deer. Currently, hunting is the most cost-effective way to manage deer populations. We are interested in how hunting impacts the affinity for deer, in addition to how the COVID-19 pandemic plays a role in the perception of deer. Online media posts were analyzed using a social media listening platform, NetBase, for the time period of January 1, 2018 to December 31, 2021. Volume of mentions and affinity via net sentiment were collected at the state level on a weekly basis, and the national level on a daily basis. We utilize an OLS regression with dummies for deer hunting season and COVID at the state level to determine the impacts of hunting seasons and the pandemic on net sentiment. We find that deer hunting being open negatively impacts net sentiment of deer. We utilize Pearson correlations to study the impact of deer management via OTC deer hunting privilege issuance in relation to affinity for deer. We find that OTC privilege issuance is positively correlated with affinity for deer in some states, but the impact on affinity may diminish over time.</p>

<p> </p> <p>This dissertation consists of three essays that examine the response of small businesses to disruptions in their environment. The first two essays focused on small non-farm businesses in the United States and how they deal with natural disasters. The last essay examined smallholder farm households in Malawi, and how their household labor allocation decisions are affected by land allocation to estates in their communities. The individual essays are summarized as follows:</p> <p>Essay 1: <em>A Conditional Process Approach to Understanding the Role of Adjustment Strategies and Disaster Experience in Racial Disparities in Small Business Performance. </em>Considering that most minority owned businesses have limited access to formal systems, this essay explored how race could indirectly affect business performance (measured as percentage revenue growth) through the adoption of three informal strategies: customer base expansion, supplier base expansion and family adjustment strategies. It also explored whether these indirect effects are moderated by experience with natural disaster. The results showed that being a racial minority was positively associated with revenue growth such that on average, minority business owners experienced 29% higher revenue growth than white-owned businesses (p<0.05) on business performance. It also showed a modest indirect effect of race on revenue growth through each mediating strategy (p<0.5). However, the results did not support a moderating role for disaster experience. </p> <p>Essay 2: <em>Willingness to Pay for Comprehensive Cyclone Insurance Coverage by Small Business Owners: Evidence from the Coastal States of the United States</em>. Small businesses in the coastal United States are usually uninsured or underinsured for cyclone events. The underinsuring of these businesses could be a result of limited insurance coverage as well as individual characteristics of small business owners. Using a discrete choice experiment, this essay used a hypothetical comprehensive cyclone insurance to understand what insurance attributes are important to small business owners. It also examined the role of previous disaster experience, charity hazard as well as temporal orientation on the willingness to pay for the disaster insurance. This study used a discrete choice experiment to elicit insurance preferences from small coastal businesses which employed less than 100 employees. A mixed logit model was used to analyze the data. The results showed that business owners exhibited positive marginal utilities from policies that covered flood, windstorm, and business interruption regardless of the combination. Notably, the mixed logit model showed that on average, business owners were willing to pay up to 450%, 472%, and 482% more than their total monthly business insurance premium payment for insurance that covers flood and business interruption, windstorm and business interruption, and flood, windstorm and business interruption respectively. Ordinary Least Squares (OLS) regression showed that respondents who had previously experienced cyclones were more willing to pay for the presented insurance policies than those who have not. Future orientation was also found to be positively associated with the marginal willingness to pay for the insurance policies.</p> <p>Essay 3: <em>Estates and Small-Holder Agricultural Labor Dynamics in Sub-Saharan Africa:</em> <em>A Case Study of Malawi. </em>Estates are larger than the average farm holdings, which mostly grow one crop, require large capital investment, are centrally managed and rely a lot on hired labor. With such large investments in agricultural land, the labor decisions of smallholder households in Africa will likely be altered. This essay therefore examined the role of estate farms on smallholders’ allocation of labor between on-farm, and off-farm demand and supply of casual labor using the <em>ganyu</em> system of Malawi as a case-study. Using the Malawi Integrated Household Panel survey covering the years 2010, 2013, 2016, and 2019, we estimated the effect of estates on the participation of smallholders on these labor decisions as well as the number of days spent in each activity. We also investigated the effect of these estates on community agricultural labor (<em>ganyu) </em>wage rates and the share of income accruable to ganyu and crop production. Linear probability (LPM), as well as tobit-correlated random effects (CRE) regressions were used to test these effects. Both models showed that the share of estates had a negative correlation with <em>ganyu </em>demand. The Tobit CRE regression showed that on average a 1% increase in the percentage share of agricultural land occupied by estates was associated with a modest 0.04% (p<0.01) decrease in the number of days <em>ganyu </em>labor was demanded, and a 0.02% increase in the number of days household members spent on their own farms. Further results showed that households in communities with higher shares of estates participated in less non-crop farming activities especially wage employment. We also found that the negative relationship between estates and <em>ganyu </em>demand was accentuated among households with higher levels of assets, and farm income. Finally, we found a modest negative relationship between share of estates and community <em>ganyu </em>wage rates </p>

<p>  </p> <p>Cattle derived food, like beef and dairy, have long been a staple of our human diets and continue to be prominent in our days. This prominence and their relevance naturally extend to our economies. According to the U.S. Department of Agriculture, Economic Research Service (2022), cattle production is the most important agricultural industry in the US representing about 17% of the $391 billion total cash receipts for agricultural commodities in 2021.</p> <p><br></p> <p>Economists have looked into cattle derived products from a wide array of perspectives focusing on the product itself, for example beef, but also in the forces of supply and demand that at times are external to product attributes. The effect of supply and demand shocks on agricultural markets have been heavily considered in the literature (Thomsen and McKenzie, 2001; McKenzie and Thomsen, 2001; Lusk and Schroeder, 2002, Piggott and Marsh, 2004). Yet another important aspect of agricultural markets is price determination and the body of literature in this area is ample (Tomek & Robinson, 2003). Recent phenomena in the world, like the availability of information, good or bad, in the most current, voluminous and accessible way that we have ever seen, could be a new force in price determination of agricultural products. My research contributes to such strains of literature by investigating perceptions and willingness to pay for beef attributes, market shocks in beef markets, and the role of online media in dairy prices.</p> <p><br></p> <p>Beef attributes, and their relative valuation by consumers, have been studied to assist in understanding consumer demand for beef. Given the relevance of such attributes in consumer’s mind, researchers have sought to study how to profitably provide those beef attributes demanded by consumers. Addressing consumer demands for tenderness, an important attribute (Schroeder and Mark, 2000), aging beef has been proved to be a technology that improves flavor, tenderness and juiciness (Kim, Kemp & Samuelson, 2016). By using aging processes, the same cattle carcass can generate more highly valued beef products. I study the willingness to pay for aging and USDA grade in beef, to understand valuation of attributes by consumers with various demographics. </p> <p><br></p> <p>In beef markets, the heterogeneity of beef cuts in their usage, pricing and distribution channels is crucial. Supply and demand shocks can affect individual cuts in different ways (Ortez et al, 2022). With some beef cuts relying heavily on restaurant sales more than others, this offers a good opportunity to introduce a new concept in beef market analysis, namely the price relationship amongst beef cuts and its response to different market shocks. The traditional discussion around spreads in meat focus on differences in price at separate steps in the supply chain, namely farm, wholesale and retail. However, little attention has been given to the relative differences in prices of specific cuts of beef.</p> <p><br></p> <p>The potential influence of online media chatter in its sentiment and volume has largely been under appreciated in the Agricultural Economics literature. A predecessor in this area is Tonsor and Olynk (2011) who first established a connection between news activity and economic fundamentals in agriculture. The advent of the internet may have the ability to decrease information asymmetry and bridge the information gap between consumers, producers and market products. Online media listening allows for data collection efficiently and in real time (Widmar, 2019) and it may be a relevant aspect in the decision making of agricultural and food industries. Moved by this endeavor, I seek to understand if potential relationships between online media chatter sentiment and volume with futures prices in dairy products exist.</p> <p>  </p>

No description available.

O fósforo é apontado como o principal responsável pelo enriquecimento nutricional de mananciais de abastecimento público, desencadeando por meio do fenômeno de eutrofização, a floração de grupos algais tóxicos e, portanto a sua remoção passa a ter grande significado para a saúde pública e para o meio ambiente. O presente trabalho foi desenvolvido com os objetivos de: avaliar a eficiência de remoção de fósforo do efluente de um sistema convencional de lodos ativados (Estação de Tratamento de Esgotos de Barueri) pelo lodo de uma estação de tratamento de água, que utiliza sulfato de alumínio como coagulante (Estação de Tratamento de Água do Alto Cotia) e verificar a influência das seguintes variáveis nesta remoção: tempo de permanência do lodo no decantador, dosagem de lodo, potencial zeta, teor de matéria orgânica no lodo, pH da mistura lodo/efluente e uso de polímero na coagulação/floculação da água bruta. Para o desenvolvimento prático da pesquisa, foram realizados ensaios de jarros, variando as condições operacionais, de tal forma a averiguar o efeito das variáveis mencionadas anteriormente na remoção do fósforo. Observou-se que esta remoção era dependente do pH; da dosagem de lodo; do tempo de permanência do mesmo no decantador; do tempo de mistura e da presença de polímero. Independia do potencial zeta e do tempo de sedimentação. A máxima remoção obtida foi de 100% (concentração inicial de 2,9 mg P/L), em pH de 4,5, com dosagem de 37 mg lodo/L, tempo de mistura de 15 minutos a 40 s-1 de gradiente, tempo de sedimentação de 30 minutos, tempo de permanência do lodo no decantador de 80 dias, sem polímero. Nestas condições, a concentração de fósforo do efluente tratado foi de 0,01mg P/L. Os resultados obtidos no presente trabalho sinalizam uma alternativa tecnológica, que pode vir a ser utilizada em projetos sustentáveis, em que as estações de tratamento de esgotos e estações de tratamento de água sejam planejadas de forma integrada, considerando o reaproveitamento e encaminhamento do lodo de ETA como insumo a ser utilizado no fim do processo de tratamento de esgotos para remoção de fósforo do efluente final, em consonância com os conceitos de produção mais limpa na busca da qualidade. / Phosphorus is considered as the main responsible for the nutritional enrichment of reservoirs of public drinking water supplies, because eutrophication process has resulted in toxic algae blooms, and therefore its removal has a great significance since these toxins represent a public health risk and environment. The aim of this research work was to evaluate the efficiency of removal of phosphate from activated sludge process (Barueri Wastewater Treatment Plant) by sludge from water treatment plant that uses aluminum sulfate as coagulant (WTP Alto Cotia) and verify the influence of following operational parameters in this removal: aging of sludge, sludge dose, zeta potential, mixing time, sedimentation time, concentration of organic matter, pH and use of polymer in coagulation/flocculation process. For the experimental research, the jar tests were operated with different conditions. The removal of phosphate was dependent of pH, sludge dose, aging of sludge, mixing time and presence of polymer. It was independent of zeta potential and sedimentation time. It was verified that maximum efficiency of phosphate removal was around 100% (initial concentration = 2,9 mgP/L), in pH 4,5 with the use of 37 mg of sludge from Alto Cotia Water Treatment Plant per liter of effluent from Barueri Wastewater Treatment Plant, with a mixing time of 15 minutes at 40 s-1, 30 minutes for sedimentation time, 80 days for aging of sludge, without polymer. Under these conditions it was obtained phosphate concentrations around 0,01mgP/L. Results obtained in this research work show a technological alternative, that can be used in projects, that sewage and water treatment plants can be planned together, considering the reuse and forwarding the water treatment plant sludge as beneficial use in the end of the sewage treatment process for the phosphorus removal, in consonance with concepts of a cleaner production practices in Environmental Management Systems.

Grande parte do lodo gerado em ETAs no Brasil ainda é disposta em rios ou em aterros sanitários. Contudo, principalmente em grandes centros urbanos, condições de licenciamento ambiental restritivas e custos logísticos crescentes tem levantado interesse em usos benéficos para esse resíduo. Um obstáculo para a mudança de paradigma recai no fato de que muito raramente operadores e projetistas de ETAs nacionais conseguirem prever, com algum grau de confiabilidade, a massa e volume de resíduos produzidos pelo tratamento da água bruta. Geralmente, usa-se para esse fim fórmulas empíricas, que relacionam a produção de lodo à concentração de sólidos em suspensão totais (SST) na água bruta e à dosagem de produtos químicos. Os objetivos deste trabalho são: comparar o desempenho de dois dos principais métodos quantitativos de estimativa de produção de lodo o método de fórmulas empíricas, e o do balanço de massa; investigar a prática disseminada de se estimar a concentração de sólidos em suspensão totais na água bruta por meio de modelos de regressão linear com a turbidez como variável independente; e delinear condições para a aplicação dessa correlação. Foram utilizados dados de seis ETAs de ciclo completo operadas pela SABESP (ABV, Alto Cotia, Cubatão, Guaraú, Franca e Presidente Prudente), além de dados de monitoramento de 130 estações de monitoramento de águas superficiais da CETESB. Os resultados sugerem que a identificação de correlações significativas entre concentração de SST e turbidez é elusiva, e não constitui tarefa trivial. Do universo de 130 estações da CETESB, somente 7 apresentaram correlação significativa; das ETAs, somente Presidente Prudente. Modelos de regressão alternativos utilizando outras variáveis (cor, vazão média mensal e mês), combinadas com a turbidez ou isoladamente, foram desenvolvidos. Somente a inclusão do mês como variável categórica foi capaz de aumentar o poder explicativo do modelo baseado exclusivamente na turbidez, sugerindo que a relação entre turbidez e concentração de SST é variável sazonalmente. Mediante a comparação com balanços de massa, foram identificados alguns fatores que afetam o poder de predição da fórmula empírica desenvolvida pela American Water Works Association, algumas vezes de maneira drástica. Em geral, conclui-se que o uso de fórmulas empíricas principalmente em conjunto com modelos de regressão entre concentração de SST e turbidez possa não ser recomendável. / Most of the water treatment plant (WTP) residuals generated in Brazil is still discharged in water bodies, or disposed of in landfills. However, especially in large urban areas, ever stringent conditions for environmental permits e rising logistical costs have put into focus beneficial uses for those residuals. A major obstacle for paradigm change in that aspect lies in the fact that very rarely water treatment plant operators and designers are able to predict with some degree of certainty the mass and volume of residuals produced by the treatment process. Usually, empirical formulas are used for that end, which relates the residuals production rate to the concentration of total suspended solids (TSS) in the raw water, and the chemicals dose. The objectives of this work are: to compare the performance of two of the main quantitative estimation methods for residuals production the empirical formulas and the mass balance; to investigate the widespread practice of estimating the concentration of TSS using turbidity as a surrogate; and to identify the conditions under which such procedure is acceptable. For that end, data from six WTPs operated by SABESP (ABV, Alto Cotia, Cubatão, Guaraú, Franca e Presidente Prudente), plus 130 surface water monitoring stations operated by CETESB, was analyzed. Alternative regression models, employing other independent variables (color, average monthly flow and month) singly or in combination with turbidity, were developed. Only the inclusion of the month as a categorical variable was capable of enhancing the explaining power of the turbidity model, suggesting that the relation between turbidity and TSS concentration is seasonally variable. The results suggest that identification of such significant correlations between TSS concentration and turbidity is elusive at best, and doesn\'t amount to a trivial task. Out of the universe of 130 monitoring stations, in only 7 a good degree of correlation was found; of the WTPs, that was the case only in Presidente Prudente. Through the comparison with the mass balances, some factors that affect the predictive power of the American Water Works Association sometimes drastically a were identified. In general, it is concluded that the use of empirical formulas especially when combined with turbidity and TSS concentration regression models may not be recommended.