Humid Tropical Climate Research Articles

Urbanites’ outdoor thermal comfort in the informal urban fabric of warm-humid Dar es Salaam, Tanzania

In warm humid tropical climates, the outdoor environment defines the lives of the majority of the population in terms of social and economic aspects. Improvement of the outdoor thermal environment encourages social and economic prosperity of the urbanites. This paper explores urbanites’ thermal comfort in the informal urban fabric of warm humid Dar es Salaam, Tanzania. Simultaneously, the study conducted micrometeorological measurements and a questionnaire survey consisting of 1541 respondents for both the warm and cool seasons. The thermal indices, Standard Effective Temperature (SET*), Universal Thermal Comfort Index (UTCI) and Physiological Equivalent Temperature (PET) were calculated. Results show that urbanites of the informal urban fabric areas experience both narrower and higher thermal comfort ranges when compared to both similar climates and other types of climate in the formal urban fabric context. Thermal acceptable ranges were found to be 30.2−32.5 °C and 23.4−27.4 °C for UTCI and SET* respectively. Despite the fact that the results showed the high adaptive capacity of the urbanites, they also revealed the urbanites’ tolerance to high thermal index temperatures due to the limited adaptive options available within the informal urban fabric morphology. The study findings could contribute significantly to the upgrading of informal settlements.

Evaluation of the environmental parameters of battery-caged poultry house in the humid tropical climate

Heat stress is a key factor affecting the productions of the animals. In laying birds, it could cause loss of body weight and high mortality. To this end, a study was carried out in a naturally ventilated, tier-caged layer house to evaluate the environmental parameters and the heat stress index within the building during hot weather period. Throughout the study, the environmental parameters (air temperature, relative humidity and air velocity), inside and outside the experimental building were measured and recorded. The heat stress index using the temperature-humidity index (THI) was also estimated. The results of the study indicated that laying birds in this study were most of their lifetime subjected to hot conditions which could have a significant effect on their performances. It was also found out that the air velocity within the building was very low (0.07 ms-1 to 0.58 ms1) which could not provide a cool environment for the birds. The heat stress index (THI) inside laying bird building was found to be mostly influenced by high relative humidity compared to ambient temperature. Therefore, it would be appropriate if the airflow distribution inside the poultry building, in this study, could be evaluated using computational fluid dynamics to understand the velocity profile within the building. This could assist engineers to redesign the building and make it appropriate for laying birds in the humid tropical climate.

Climate Responsive Architecture in Jakarta’s Apartments

Almost every day, apartment buildings in Jakarta have to face a long hour exposure of solar heating which caused temperature gain inside the building. It creates a high room temperature and requires an air-conditioning system to reduce room temperature. This problem arises from the ineffective function of architecture design elements used. The method used in this research is literature study and analyze it with the case study of three apartments located in Jakarta. The principal design of climate-responsive architecture in Jakarta (tropical humid climate city) is a passive cooling strategy which used to prevent/avoid solar heat exposure and to release heat inside the building. There are two categories of design elements function used: 1) as building envelope/façade (such as shadings, ventilation, roof, and building materials) and 2) as building placement (such as building thickness and orientation, ventilations, building landscape, etc.). Three apartments located in Jakarta were analyzed with the findings, and the design elements used were found ineffective as climate filter in Jakarta (the three apartments still rely on air-conditioned systems-active cooling approach to reduce the transmitted solar heat and cooling rooms). The result of this study is a solution/recommendation for designing architecture elements that functioned as climate filter and have better respond to Jakarta’s climate.

Yield, quality, water productivity and economic assessment of sweet corn under irrigation and nitrogen management in humid tropical climate

A field experiment was conducted during three consecutive winter seasons of 2013-14 to 2015-16 in the Indo-Gangetic plains encompassing humid tropical climatic region to study four irrigation regimes (gravity drip at 1.0, 0.8 and 0.6 ETc and surface irrigation) and four nitrogen management (100% RDN, 75% RDN + 25% RDN as vermicompost, 75% RDN + 25% RDN as FYM and 75% RDN + 25% RDN as mustard oilcake) on sweet corn. The results showed that surface irrigation with 75% RDN + 25% RDN as vermicompost was found the best treatment combination for maximum yield and economic realization which being competitive with drip irrigation at 1.0 ETc with 75% RDN + 25% RDN as vermicompost. Relatively higher quality parameters and moderate water productivity were observed with drip irrigation schedule at 1.0 ETc. The findings portray the precise planning and efficient management of available water and nitrogen resources for sweet corn growers.

Outdoor Thermal Comfort and Building Energy Use Potential in Different Land-Use Areas in Tropical Cities: Case of Kuala Lumpur

High air temperature and high humidity, combined with low wind speeds, are common trends in the tropical urban climates, which collectively govern heat-induced health risks and outdoor thermal comfort under the given hygrothermal conditions. The impact of different urban land-uses on air temperatures is well-documented by many studies focusing on the urban heat island phenomenon; however, an integrated study of air temperature and humidity, i.e., the human-perceived temperatures, in different land-use areas is essential to understand the impact of hot and humid tropical urban climates on the thermal comfort of urban dwellers for an appraisal of potential health risks and the associated building energy use potential. In this study, we show through near-surface monitoring how these factors vary in distinct land-use areas of Kuala Lumpur city, characterized by different morphological features (high-rise vs. low-rise; compact vs. open), level of anthropogenic heating and evapotranspiration (built-up vs. green areas), and building materials (concrete buildings vs. traditional Malay homes in timber) based on the calculated heat index (HI), apparent temperature (TApp) and equivalent temperature (TE) values in wet and dry seasons. The results show that the felt-like temperatures are almost always higher than the air temperatures in all land-use areas, and this difference is highest in daytime temperatures in green areas during the dry season, by up to about 8 °C (HI)/5 °C (TApp). The TE values are also up to 9% higher in these areas than in built-up areas. We conclude that tackling urban heat island without compromising thermal comfort levels, hence encouraging energy use reduction in buildings to cope with outdoor conditions requires a careful management of humidity levels, as well as a careful selection of building morphology and materials.

Early-design sensitivity of radiant cooled office buildings in the tropics for building performance

The research community has worked on improving the design, performance, and operation of radiant system technologies; however, the interactions between architectural design decisions and radiant cooling systems design in the tropics – where radiant system design and operation represents a challenge due to high external heat gains and latent loads – have been left unexplored by existing work. This manuscript (1) addresses the holistic early-design of effective radiant cooling systems and the architectural environments that they serve in hot and humid tropical climates, (2) analyses how different design choices and their interaction affect buildings performance compared to conventional all-air systems, and (3) proposes preliminary early-design indications of the parameters values to adopt when designing radiant cooled office buildings in the tropics to achieve high multi-objective design goals. Morris sensitivity analysis is used to analyse the impact of 13 different building and system design parameters on comfort, system and energy performances for 3 radiant systems typologies applied to a parametric office building in the tropical climate of Singapore. The elementary effect (EE) of each parameter is analysed based on 8200 individual EnergyPlus simulation models being run, and the impact, interactions & (non) linear effects of different design factors are assessed. It is found that radiant cooling systems require different early-design phase considerations than conventional air-based cooling systems since different parameters prove to be dominant or significant. All three radiant system typologies, if coupled with efficient operational strategies and a complimentary set of design variables, ensure high multi-objective building performance, showing how the implementation of radiant cooling technologies could be beneficial for a tropical climate. The window solar heat gain coefficient and the façade window-to-wall ratio play a key role in this effort with respective values falling below or equal to 54% and 57%. The system set-point temperature has an increased importance for operational efficiency allowing high dry-bulb room temperatures ranging from 24.8 °C to 27 °C.

Investigation of Solar Photovoltaic-Thermal (PVT) and Solar Photovoltaic (PV) Performance: A Case Study in Ghana

The main objective of this paper is to experimentally assess the real-life outdoor performance of a photovoltaic-thermal (PVT) module against a conventional photovoltaic (PV) system in a hot humid tropical climate in Ghana. An experimental setup comprising a water-based mono-crystalline silicon PVT and an ordinary mono-crystalline silicon PV was installed on a rooftop at the Kwame Nkrumah University of Science and Technology in Kumasi and results evaluated for the entire year of 2019. It was observed that the annual total output energy of PV module was 194.79 kWh/m2 whereas that of the PVT for electrical and thermal outputs were 149.92 kWh/m2 and 1087.79 kWh/m2, respectively. The yearly average daily electrical energy yield for the PV and PVT were 3.21 kWh/kWp/day and 2.72 kWh/kWp/day, respectively. The annual performance ratios for the PV and PVT (based on electrical energy output only) were 79.2% and 51.6%, respectively, whilst their capacity factors were, respectively, 13.4% and 11.3%. Whereas the highest monthly mean efficiency recorded for the PV was 12.7%, the highest combined measured monthly mean electrical/thermal efficiency of the PVT was 56.1%. It is also concluded that the PVT is a worthy prospective alternative energy source in off-grid situations.

IDENTIFIKASI ADAPTASI ARSITEKTUR TROPIS PADA BANGUNAN KOLONIAL STUDI KASUS: MUSEUM PERKEBUNAN INDONESIA

Climate is the most important factor in architectural design, climate greatly influences the shape and appearance of buildings. Colonial buildings are buildings that have experienced a mix of European architects with local adaptation processes including the climate in Indonesia, one of which is the Indonesian Plantation Museum building in the city of Medan. Indonesia is included in a region that has a humid tropical climate, where the tropical climate has certain characteristics caused by solar heat, high humidity, rainfall, and wind movement. The purpose of this study is to identify aspects of tropicality in colonial buildings that have adapted to tropical climates. The method used in the study is the Case Study Qualitative Method with observation and identification of external forms (building orientation, roof, terraces and outside space) and the shapes in buildings (Patterns of Space, Floors, Walls, and Openings). The results of this study is the Indonesian Plantation Museum tends to be able to adapt to the local climate even though the shape and style of the building comes from Europeans,known as transition architecture. The building elements that are more adapted to the tropical climate are roofs with slopes of more than 30º, openings and cross ventilation, marble and wood floors and very thick concrete walls.

Peningkatan Kenyamanan Termal dan Pencahayaan Alam Gedung Sekolah Dasar di Kawasan Padat Hunian di Surabaya

<p class="AbstractTitle"><em>A humid tropical climate characterized by high temperatures, relative humidity and solar radiation</em><em> </em><em>results in uncomfortable environmental conditions. Discomfort will be worse if the building is in a dense urban area. Densely building masses often weaken the local wind speed which is necessary for evaporative cooling process in tropical climate. In addition, the narrow distance between buildings can reduce access to daylight. Both of these environmental problems were experienced by SDIT Al Uswah Surabaya, which building is located in a densely populated neighbourhood. Along with the development program of educational facilities and infrastructure at the school, improving environmental conditions with passive concept is maintained and prioritized. Embodiment of the environment with the Selective Environment approach is used in this activity. The results of this activity will be in the form of design proposals for improving ventilation and lighting in classrooms. The limitation of expanding openings becomes an obstacle in fulfilling the natural ventilation and lighting requirements. In addition, the design of a three-storey building with a single loaded corridor requires special consideration for the design of sun shading that is safe for elementary school-age children, but still supports passive lighting and ventilation.</em></p>

A numerical and experimental investigation of the effectiveness of green roofs in tropical environments: The case study of Mauritius in mid and late winter

The present work is a preliminary assessment of the performance of green roof at Reduit in Mauritius, located at latitude 20.23∘S and longitude 57.49∘E (Indian Ocean), which is influenced by a tropical humid climate. The efficiency of the green roof is gauged by evaluating its effect on indoor temperature fluctuations, conductive heat fluxes and the daily peak indoor temperature. On site measurements of weather data and indoor temperature are collected round the clock from July 11, 2017 to October 08, 2017. It is found that green roof increases the thermal mass of the experimental cells thereby reducing the fluctuations in indoor temperature. The conductive heat flux variation is significantly low in the case of the green roof. The green roof reduces the daily peak indoor temperature, which is attenuated significantly as compared to a conventional roof. A one dimensional mathematical model is also proposed in order to simulate the evolution of the heat and moisture transfer in a porous multilayer material. The model is validated using the measured data.

Thermoregulatory Responses of Heat Acclimatized Buffaloes to Simulated Heat Waves.

Simple SummaryThe simulated heat wave triggered a relevant thermoregulatory response in heat-acclimatized buffaloes. During the simulated heat wave the high respiratory rate and seating rate limited the heat storage and the levels of hyperthermia. Moderate and transient hyperthermia combined with complete recovery of homeothermy during the night prevented changes in blood parameters, except for ion potassium. The high sweating rates seem to have been crucial for the homeothermy’s maintenance. For the first time, early in the morning, adaptive hypothermia was recorded in buffaloes.Climate change is seen as a significant threat to the sustainability of livestock production systems in many parts of the world, particularly in tropical regions. Extreme meteorological events can result in catastrophic production and death of livestock. Heat waves in particular can push vulnerable animals beyond their survival threshold limits. However, there is little information about buffalo responses to sudden changes in the thermal environment, specifically the heat waves. This study aimed to quantify the thermoregulatory and blood biochemical responses of heat-acclimatized buffaloes to a simulated heat wave. The experiment was designed in a climatic chamber with two periods of 4 days each. Twelve heat acclimated buffalo heifers aged 18 months were used. The climatic chamber environment was set as follows: 4-day period (P1) simulating the same weather conditions of a summer in humid tropical climate used as a baseline, with daily cycle with Ta and RH at 27 ± 1 °C and 76% from 0600 h to 1900 h and 24 ± 1 °C and 80% from 1900 h to 0600 h, and 4-day period (P2), simulating a daily heat wave cycle, from 0600 h to 1900 h with Ta and RH kept at 36 °C and 78% and from 1900 h to 0600 h, 27 °C and 74%. All animals were subject to both treatments and data were analyzed by a repeated measure analysis of variance, with post-hoc pooling comparison performed by Tukey’s test. In P2, there was observed a significant increase in respiratory frequency (p < 0.01), found four times in P1. The sweating rates were quite high in both periods; still, there were significant increases in P2 compared to P1 (p < 0.01) (4931 and 3201 g/m2/h, respectively). A slight but significant increase in rectal temperature was observed during the day (p < 0.01), with a rising until 1900 h. The simulated heat wave in P2 did not affect the values of the erythrogram or leukogram, excluding the significant reduction in K+ (p < 0.05). The low heat storage and the subsequent fast and full recovery of the thermal balance late afternoon appear to be related to the high sweating rate values. The massive sweating rate emphasizes its relevance in the maintenance of buffalo homeothermy. The absence of changes in hematological parameters has revealed the considerable physiological resilience of buffaloes toward simulated heat waves.

The Energy Conservation With A Ventilated Roof Of Joglo’s House

The ventilation of buildings in hot and dry zones has to function differently from the warm and humid zones. When outside temperatures are rising higher than human body temperatures, cross ventilation through wide openings would not be useful; on the contrary, it would be a burden. To emphasize the sustainability of tropical homes, it is expected to maximize the use of the role of the roof opening in the building envelope in a passive manner. One passive cooling strategy is natural air. Circulation of natural ventilation in traditional Javanese built objects in humid tropical climates is used to achieve thermal comfort. Therefore, the problem that arises in this study is how far the Joglo-based roof element is in natural ventilation to form a comfortable space. This paper contains the elements of a Joglo-based house roof as a natural ventilation element. This study uses a computer simulation based on the program of CFD; the name is CFX-5, which is used to track the pattern and direction of air movement as well as the amount of air velocity and air direction in the Joglo-based roof ventilation object. The final value of these observations is between 0.389 to 0.489 m/s, which provides the majority cooling effect in the room, range between 0.489 O C - 0.589 O C. This was shown in the modified roof conditions, roof ventilation of the Joglo-Mangkurat-based roof is able to increase the speed of the air rate in the room. Keywords: energy conservation, ventilated roof, Joglo’s house.

Influence of land use on the performance of the WRF model in a humid tropical climate

This study evaluates the effect of the land use update to meteorological simulations in the Metropolitan Region of Greater Vitoria (MRGV) using the Weather Research and Forecasting (WRF) mesoscale model. WRF performance was analyzed using monitoring data like wind speed and direction, temperature, and sensible heat flux. In general, the changes in the simulations results with the updating of the land use data are quite subtle, and these values are better represented by the local data in the cold front period. The results obtained indicate a slight improvement in the wind speed and direction when land use is local for the airport station, where the mean bias reduced from − 0.124 to − 0.079, thereby better capturing smaller urban centers and the urban canopy.

Energy Efficiency and Thermal Performance of Office Buildings Integrated with Passive Strategies in Coastal Regions of Humid and Hot Tropical Climates in Madagascar

Researchers have used passive strategies, such as the implementation of thermal insulation and the use of phase change materials (PCM), in several studies, but some problems have not yet been solved. It is the case of showing the real effect of external shading combined with thermal insulation and phase change materials to improve the thermal performance and energy efficiency of office buildings in tropical coastal areas. Another pending problem to be solved is to define the impact produced by passive strategies on the performance of workers in office buildings in coastal zones. It is with a view to answering all these questions that this study was envisaged with the main objective of evaluating, analyzing, comparing, and discussing the effect of thermal insulation and phase change materials on thermal comfort and energy demand in coastal areas of hot and humid tropical climates located in the island of Madagascar. In this sense, hourly climate data for the past 30 years have served as the basis for assessing environmental conditions of future climate. It was found that the PCMs have a more significant effect on the coastal zone of hot climates than humid tropical climates. The results of the statistical analyses showed that the application of passive strategies stabilizes indoor air temperatures to between 23 °C and 28 °C in the offices, which is the recommended comfort range in these regions. In the coastal regions of Madagascar, up to 30% of cooling energy is expected to be reduced by combining the introduction of thermal insulation and PCM materials.

Niobium–tantalum oxide minerals in alluvial placer deposits from the Ngoura area, East-Cameroon

This work presents a preliminary mineralogical characterization of Nb–Ta oxide minerals from alluvial placers located in the Ngoura area, eastern Cameroon. The heavy minerals are characteristic of short hydromechanical transport and highlight the stability of Nb–Ta oxides during the weathering and transport. Nb–Ta mineralization in placer deposits from the Ngoura area may derive from local sedimentation. The assemblage of Nb–Ta oxides in the studied placers consists of tapiolite-(Fe) and tantalite-(Mn). Tapiolite-(Fe) exhibits high concentrations in Ta2O5 (78.07–80.46 wt%) and FeO (12.18–13.66 wt%) and plots within a narrow range of Ta* (0.900–0.933) and Mn* (0.037–0.119), which correspond to the ranges typically observed in tapiolite-(Fe) worldwide. Tantalite-(Mn) shows Ta2O5 contents ranging from 62.17 to 69.45 wt%, Nb2O5 from 12.09 to 17.37 wt%, MnO from 7.63 to 12.49 wt% and FeO from 1.48 to 6.62 wt%. It is also characterized by a wider range of Mn* (0.538–0.891) and relatively homogeneous Ta/(Ta + Nb) (0.683–0.779) ratios. Texturally, the studied Nb–Ta minerals exhibit oscillatory zoning characterized by bright Ta-rich zones alternating with dark Nb-rich zones. This oscillatory zoning is progressive in some minerals and the alternating bands may appear regular to wavy with gradual transitions. Oscillatory zoning in Nb–Ta oxides from the Ngoura placers is considered to be a primary magmatic feature and is tentatively explained as a result of magmas mixing, rapid cooling or degassing/decompression of the igneous system. The geomorphology and the tropical humid climate of the eastern region offer suitable conditions for the deposition of alluvial placers. Therefore, niobium-tantalum minerals from the Ngoura placers must have been sourced from the weathering and erosion of alkaline granites and pegmatites widespread in the study area.

Applying the Passivhaus standard to a terraced house in a hot and humid tropical climate – Evaluation of comfort and energy performance

In a hot and humid tropical climate, natural ventilation brings high levels of moisture into dwellings that, together with occupant activity, can result in very elevated internal relative humidity levels. Coupling these high relative humidities with high internal air temperatures creates occupant thermal discomfort, which is typically ameliorated in the tropics using energy-intensive air conditioning systems. This paper has investigated the potential benefits for thermal comfort and energy usage of applying the German Passivhaus standard to tropical dwellings. By creating a super insulated and air-tight envelope, the Passivhaus standard reduces fabric heat transfer, controls air infiltration and provides low-energy comfort. Applying this approach to a tropical terraced house might be effective but could, potentially, have an adverse impact on mechanical cooling demand. This study took an actual terraced property in Jakarta, Indonesia and thermally modelled its performance as insulation and airtightness levels were incrementally improved up to the Passivhaus standard. Field measurements in the dwelling of air temperature and relative humidity were used to validate the thermal model of the existing house. The validated model then tested the feasibility of meeting the Passivhaus energy standard for cooling in the modified tropical house. Simulation allowed the effects of air conditioning (AC) and dehumidifiers on thermal comfort and cooling loads to be investigated. The research develop the Passivhaus building model that had the floor insulation removed to let the ground floor act as a thermal sink and potentially provide radiant cooling. Analysis revealed that the building’s predicted air temperatures were affected in a beneficial way by having the Passivhaus without floor insulation. Practical application: Cooling in hot and humid tropical region is an energy-intensive approach. Design approaches that can bring comfort and save energy for the occupant are essential. The success of Passivhaus standard in mild climate might be transferable to bring comfort in tropical housing. Best practice can be developed by analysing the Passivhaus building performance in hot and humid tropical region.

SOIL LOSS AND CASSAVA YIELD UNDER RIDGE TILLAGE IN HUMID TROPICAL CLIMATE OF SUMATERA, INDONESIA

Erosion is one of problem threatens the soil resource caused soil degradation. Applying the ridges system and organic fertilizer contributes to suppressing runoff and erosion. This study aims to determine the effect of applying different ridges system and the organic fertilizer on the runoff, soil erosion, nutrients loss of soil, nutrient enrichment ratio, starch content, growth, and yield of cassava on 12.5% slope land. The research was conducted at the field experiment, University of Lampung, under a humid tropical climate. This study used a Randomized Complete Block Design, which was arranged factorially with two factors, ridges system and organic fertilizer (organonitrofos) and four replications. Factor one is consists of G1 (ridges in the same direction with the slope) and G2 (ridges in the opposite direction with the slope), while factor two is consists of P0 (Organonitrofos 0 tons/ha) and P1 (Orgononitrofos 20 tons/ha). The results showed that the application of the ridges in the opposite direction with the slope significantly reduces the runoff 42.63%, soil erosion 61.68%, and suppress nutrient loss of N-total by 61.85%, P-available by 57.92%, K-total by 80.41% and C-organic by 61.22%, compared to ridges in the same direction with the slope. However, ridges systems do not give a significant difference to starch content, growth, and cassava yield. Physical obstacles formed by ridges in the opposite direction with the slope will force water to infiltrate into the soil so that the runoff rate, erosion, and nutrients loss can be reduced significantly. In reverse, the organic fertilizers do not affect all variables. The ridges system and the organic fertilizer did not significantly affect the starch content, growth, and yield of cassava. That caused by the application of synthetic fertilizers at the same dose (standard dose for planting cassava) in each experimental unit that fertilizer already enough to grow optimally.

Assessment and characterization of groundwater quality under domestic distribution using hydrochemical and multivariate statistical methods in Bafia, Cameroon

The best knowledge of physico-geochemical content of water helps to cope with adequacy between water availability and its importance. Thus, in BAFIA where groundwater is used in households, it is mandatory to evaluate and characterize the quality of that water. BAFIA is an important area of Cameroon due to its geographical position, growing population and associated needs. Located between an equatorial climate in the western region and a humid tropical climate in the eastern region, this area contains an aquifer system that represents sequences of shales, mica quarry, biotite gneiss, post-tectonic granites, and ortho-amphibolite. Groundwater flows aquifers recharge areas and provides base flows to supply drinking water to study area. The objective of this work was to assess the physicochemical and bacteriological quality of groundwater, to explain the phenomena that cause its mineralization in and around the BAFIA area and to correlate these different ions. We only included boreholes that had a good flow rate to meet the need to supply a large number of populations with water for domestic use. We conducted an analytical study of the physicochemical and bacteriological parameters of the elements collected from the water samples. The results were processed using hydro-chemical methods (Piper diagram, distribution maps of chemical elements) for a study of water typology and multivariate statistical analysis techniques. Principal component analysis (PCR) and ascending hierarchical classification (CHA) analysis were used to determine the phenomena causing water mineralization and the links between these waters, respectively. Our results showed that: the waters analyzed in the study area were slightly basic and moderately mineralized. Chemical parameter grades were below the world health organization (WHO) standard; except for iron. Most of the water was chlorinated and sulfated calsic and magnesic. Three phenomena have been at the origin of water mineralization: anthropogenic activity, recharge of groundwater (soil infiltration) and water-rock contact (main ion production mechanism).

Pilot scale study on characterization and performance of aerobic granular sludge to treat domestic wastewater

Aerobic granular sludge (AGS) is a wastewater treatment technology that is known for having unique advantages such as great settling ability, high biomass level, good shock resistance, and able to withstand high organic loading rate (OLR) and toxic pollutants. Since studies on AGS development are mostly conducted in laboratory scale, the detailed knowledge regarding the pilot scale study is still limited especially for hot and humid tropical climate condition. Therefore, this study focused on the characteristics and performance of AGS cultivated in a pilot-scale bioreactor for hot and humid tropical climate condition, specifically in Malaysia. The formation of AGS as well as biomass concentration were also investigated during the treatment of real domestic wastewater. From the result, it was found that the highest average diameter of the cultivated mature granules was 3.36 mm with a biomass concentration of 12.48 g L−1 after 93 days of operation. The aerobic granular sludge also achieved promising removal rates of 89 %, 75 %, 96 %, and 93 % for COD, phosphate, ammoniacal nitrogen, and total inorganic nitrogen, respectively.

Influência da Espessura da Camada de solo na Proteção dos aquíferos Cársticos sob os Climas Tropical Úmido e Europeu Mediterrâneo, pelo Método de Vulnerabilidade COP

Carste se refere a um estilo especial de paisagem onde coexistem cavernas e um extenso sistema de água subterrânea desenvolvido especialmente sobre rochas solúveis. Os aquíferos cársticos possuem alta fragilidade devido à circulação da água por meio de condutos, fissuras ou fraturas. Uma vez contaminados sua descontaminação é quase impossível. Métodos de vulnerabilidade foram criados para prever a susceptibilidade da contaminação de um aquífero por atividades antrópicas. São vários métodos, mas poucos são de uso específico ao carste. O método COP, acrônimo utilizado para designar os parâmetros C=concentração de fluxo, O=camadas sobrepostas e P=precipitação, foi desenvolvido para proteção de aquíferos cársticos de países europeus de clima mediterrâneo e apresentou bons resultados. Porém, sua aplicação no carste de clima tropical úmido requer modificações, principalmente porque há diferenças na camada protetora do aquífero (Fator O) entre o carste Mediterrâneo Europeu e o carste tropical úmido, que apresenta maior espessura de solo. Neste artigo, foram simuladas duas situações para uma área cárstica de 240 km2: uma com a aplicação direta do método COP original e outra adaptando o método a espessuras mais realistas do solo tropical. Os resultados mostram que a aplicação direta do método proporcionou uma proteção predominantemente alta para o Fator O, que se altera a predominantemente moderada para a realidade do carste de clima tropical úmido, apontando para a necessidade de adaptação desse fator.