This study evaluated the efficiency of coagulation/flocculation, sedimentation and filtration processes using the combination of natural coagulant from Moringa oleifera Lam (MO) and synthetic coagulant aluminum polychloride (PAC) for water treatment. Raw water was obtained from the Pirapó River Basin, Maringá, Paraná State, Brazil. Coagulation/flocculation and sedimentation assays were carried out in a Jar Test. A two-layer rapid filter filled with sand and anthracite was used in the filtration stage. Water quality and therefore the efficiency of the process were determined by means of the analysis of physical, chemical and bacteriological parameters, including the determination of floc size and zeta potential. The utilization of MO contributed to the reduction of the required demand of synthetic coagulant PAC. The association of coagulants, with 80%/20% or 60%/40% of MO/PAC, ensured an improvement of water quality parameters, such as apparent color, turbidity and UV254nm, as well as the possibility of water production with adequate potability standard.

The present study aims to optimize the operational conditions in surface water coagulation/flocculation and sedimentation step, besides evaluating the association between seeds ofMoringa oleiferaLam. (M. oleifera) and the synthetic coagulant aluminium sulphate for surface water treatment. The assays were performed in Jar Test using surface water from Pirapó River basin, Maringá, PR. It was observed that the operational conditions affect the coagulation/flocculation and sedimentation process efficiency. Optimal operational conditions for coagulants association are as follows: rapid mixing velocity (RMV) of 105 rpm, rapid mixing times (RMT) of 1 min, slow mixing velocity (SMV) of 30 rpm, slow mixing times (SMT) of 15 min, and sedimentation time (ST) of 15 min; this enables an improvement in the process, contributing to a reduction in synthetic coagulant aluminium sulphate demand of up to 30%, combined with an increase inM. oleiferadosage, not affecting the coagulation/flocculation and sedimentation process efficiency, considering the water pH range between 7 and 9.

The construction of coagulation diagrams is provided to obtain colour, turbidity and compounds with absorption at UV_{254 nm} removal by associating the coagulants Moringa oleifera Lam and aluminium sulphate to define the optimal conditions of the process in water treatment. Experiments were performed in jar test with several coagulant dosages and coagulation pH. Optimal conditions for raw water with high colour/turbidity were obtained at pH values ranging from 7.5 to 8. After filtration, three dosages of association aluminium sulphate—M. oleifera, 25 ppm/300 ppm; 20 ppm/350 ppm and 15 ppm/400 ppm, performed efficient removal of evaluated parameters, namely 97.7% plus for colour and turbidity and 68.2% for compounds with absorption at UV_{254 nm}. Results showed that the use of coagulation diagram is useful since it provides development of tests in optimal conditions, depending on water initial characteristics. The association of coagulants aluminium sulphate—M. oleifera may be considered an alternative technique for conventional water treatment.

Existem vários estudos sobre coagulantes naturais, contudo, informações sobre as condições de operação no processo de coagulação/ floculação e sedimentação ainda são insuficientes, principalmente relacionadas aos efeitos dos coagulantes químicos em conjunto com a Moringa oleifera Lam (M. oleifera). Assim, o objetivo foi avaliar a eficiência da associação dos coagulantes policloreto de alumínio (PAC) e M. oleifera na remoção de cor aparente, turbidez e compostos com absorção em UV254nm (UV254nm), em função da alteração das velocidades e tempos de mistura, a fim de se obter as condições de operações ideais para água bruta com turbidez inicial de 72,9 NTU. Os ensaios foram realizados em Jar Test, com água bruta proveniente da bacia do rio Pirapó, Maringá, PR, com dosagens de 12,5 mg.L-1 para o PAC associado a 50 mg.L-1 de M. oleifera. Para a avaliação da remoção dos parâmetros de qualidade utilizou-se delineamento fatorial 27x4, sendo vinte e sete variações quanto à velocidade de mistura rápida e lenta (VMR e VML) e tempos de mistura rápida e lenta (TMR e TML); e quatro tempos de sedimentação (TS). Por meio da aplicação do teste Tukey, observou-se que as condições de operação mais interessantes foram: 100 rpm (VMR), 1 min (TMR), 45 rpm (VML), 15 min (TML e TS), com eficiência de remoção de 97,1%, 95,8% e 85,6% para cor aparente, turbidez e UV254nm, respectivamente.

Macapá está com a qualidade de seus corpos hídricos comprometida devido à ação antrópica, já que parte da população urbana vive em áreas de ressaca, que trazem inúmeros problemas ambientais para a cidade. Além disso, as chuvas intensas aumentam a frequência de alagamentos, principalmente, para a população que vive em locais próximos aos canais de Macapá. Assim, este estudo propõe realizar a caracterização físico-química e microbiológica em dois pontos de alagamentos da cidade: o canal do Jandiá e o canal das Pedrinhas, a fim de avaliar se os parâmetros de qualidade se enquadram nos valores máximos permitidos na legislação vigente. A caracterização da água de estudo foi realizada por meio dos seguintes parâmetros de qualidade: condutividade elétrica, cor, cloreto, dureza total, ferro, nitrogênio amoniacal, oxigênio dissolvido, pH, turbidez, coliformes totais e Escherichia coli (E. coli). As análises de: condutividade elétrica, cor, ferro, oxigênio dissolvido, turbidez, coliformes totais e E. coli evidenciaram que a qualidade da água está em desacordo com a legislação vigente para águas de classe 2, confirmando que o ambiente está impactado de forma negativa, possivelmente, devido ao lançamento de resíduos sólidos e esgoto doméstico nos canais. Esses fatores contribuem para diversos riscos à saúde da população, com consequências diretamente relacionadas à doenças de veiculação hídrica e problemas ao meio ambiente, como a poluição dos canais. WATER CHARACTERIZATION IN THE JANDIÁ AND PEDRINHAS CANALS IN THE CITY OF MACAPÁ, AMAPÁ, BRAZIL ABSTRACT Macapá has had the quality of its water bodies compromised due to anthropic action since part of the urban population lives in surging sea areas, which brings countless environmental problems to the city. In addition, heavy rainfall increases the frequency of flooding, especially for the population that lives near the canals of Macapá. Accordingly, this study proposes to perform the physical-chemical and microbiological characterization of two flooding points in the city: the Jandiá Canal and the Pedrinhas Canal, in order to assess whether the quality parameters are in conformity with the maximum values allowed by current legislation. The characterization of the sample water was carried out by using the following quality parameters: electrical conductivity, color, chloride, total hardness, iron, ammoniacal nitrogen, dissolved oxygen, pH, turbidity, total coliforms, and Escherichia coli (E. coli). Analysis of: electrical conductivity, color, iron, dissolved oxygen, turbidity, total coliforms, and E. coli showed that the water quality is in disagreement with the current legislation for type 2 water, which confirm that the environment is negatively impacted, possibly due to the disposal of solid waste and domestic sewage in the channels. Such factors contribute to several health risks for the population, with consequences directly related to water-borne diseases and environmental problems, such as the pollution of the canals. Keywords: Impacted environments. Flooding points. Water quality.