Agrochemicals use in horticulture industry in Tanzania and their potential impact to water resources

The objective of this review was to analyze the existing information on the use of agrochemicals (Fertilizers and Pesticides) in the Tanzanian  horticulture industry especially the Northern regions and their potential to impacting water resources. Agrochemicals play an important role in  horticulture, and have been widely used in Tanzania for crop protection and increasing productivity. Apart from these benefits, agrochemicals have the potential to impair the quality of water resources for different end uses. Majority of communities in Tanzania depend on surface water from rivers and lakes for potable uses such as washing, drinking and domestic  animals also drink from these sources. Reports from studies done in Northern Tanzania have indicated the presence of significant levels of pesticides, phosphates and nitrates in surface and groundwater. It is  apparent that most of the horticultural farms in Northern Tanzania are located on gently sloping land adjacent to water bodies. Thus discharges of wastewaters from horticulture farms may affect the quality of water  resources through run-off and groundwater through infiltration if proper management of the agrochemicals is not well adhered to. The  agrochemicals that have been widely used and identified as potential environmental pollutants from their use as horticultural chemicals are  reviewed. The potentially adverse impacts of these agrochemicals to water resources are discussed. The review concludes with a discussion of the directions for further investigation. Keywords: Pesticides, fertilizers, wastewater, horticulture, environmen

Performance of Subsurface Flow Constructed Wetland for Domestic Wastewater Treatment

Constructed wetlands (CW) have recently emerged as efficient technology for secondary treatment of wastewater in developing countries because of its low cost, ease operation, maintenance and generally good performance. At present there are a number of small scale units of CW for wastewater treatment in Tanzania but information on their performance is scarce. This study investigated the removal efficiency of fecal bacteria indicators, inorganic nutrients and Biochemical Oxygen Demand (BOD) from wastewater by a CW at the University of Dar es Salaam. The CW received wastewater from a primary facultative pond and was a monoculture system planted with Phragmites mauritianus (> 10 years old) with one unplanted cells as control. The results showed significantly (P < 0.001) higher removal of fecal indicator bacteria, in planted than in unplanted cells. Thus, the overall E. Coli and Fecal coliform percentage removal were 92.9±6.05% and 93.2±6.13% in planted cells as compared to unplanted cell which were 75.2±21.3% and 58.7±21.2%, respectively. The BOD5 values in influent was also significantly (P < 0.001) reduced (71 ± 6.2%) in effluent of planted cells than in unplanted cells where the average percentage removal averaged 45 ± 3.3%. Similarly, nutrients were significantly (P < 0.001) removed in planted cells compared to unplanted cells. The results of this study show that plants enhanced the removal process and that the CW are efficient in wastewater treatment, supporting the ideas put forward by several researchers on the usefulness of these systems in developing countries. The system continues to perform efficiently for long time which signifies its cost effectiveness. It is recommended that CW be promoted for sewage treatment in a strategy to reduce wastewater pollution in Tanzania

Pollutants Removal Efficiency of two Mangroves Species (Avicennia marina and Rhizophora mucronata) in Treating Domestic Sewage

Bucket experiments were conducted to evaluate the effect of domestic sewage loading and inundation time on pollutants removal efficiency for cells planted with Avicennia marina and Rhizophora mucronata mangroves species. Domestic sewage from the University of Dar es Salaam primary facultative waste stabilization pond was loaded onto buckets planted with the two mangroves species and unplanted buckets (bare sediment) used as control units. Sea water was used to dilute the sewage to make desired sewage strength of 0, 25%, 50%, 75% and 100%. Inundation times of 1 week, 24 hours and 12 hours were used in these experiments. Based on the obtained results, units planted with mangroves showed optimal removal of phosphates, total phosphorous and ammonium-nitrogen at sewage loading of 100% when inundated for 1 week. There was a significant reduction in concentration of phosphorous, total phosphorous and ammonium-nitrogen observed in planted units. However, there was insignificant difference in nutrients removal between the two mangrove species. While Avicennia marina units removed phosphorous, total  phosphorous and ammonium-nitrogen by 94.49%, 93.25% and 94.76% respectively, removal efficiency of the same pollutants by Rhizophora mucronata units were 94.00%, 92.82% and 94.05%, respectively.  Generally, the removal percentage of phosphorous, total phosphorous and ammonium-nitrogen were significantly higher in 1 week inundation time than in both 24 hours and 12 hours inundation time. Based on the  performance of mangrove on nutrient removal, it was concluded that the two mangrove species could be used as phytoremediators of domestic wastewater in mangroves constructed wetlands in coastal areas.Key words: Avicennia marina, Rhizophora mucronata, domestic sewage, inundation

Wastewater Treatment for Pollution Control

Performance of a Dynamic Roughing Filter (DRF) coupled with a Horizontal Subsurface Flow Constructed Wetland (HSSFCW) in the treatment of a wastewater was studied in tropical conditions. The results show that in HSSFCW planted with Cyperus papyrus and Phragmites mauritianus in series, the removal rates of TDS, TSS, COD and BOD5 were 72.07%, 80.01%, 81.22% and 78.37%, respectively, while in the second HSSFCW planted with Cyperus papyrus only, the removal rates were 71.00%, 79.00%, 73.76 and 75.78%, respectively. HSSFCW planted with mixed macrophytes, performed better than a HSSFCW planted with single macrophyte. This was attributed to synergetic effects of Cyperus horizontal roots and Phragmites vertical plant roots weaved and entangled in cell 1 providing a good filter mat and a better bacterial attachment. Thus the use of two macrophytes planted in series was recognized to be responsible for better performance of HSSFCW cell 1 in pollutants removal from wastewater

Quality of care for the treatment for uncomplicated malaria in South-East Nigeria: how important is socioeconomic status?

Introduction: Ensuring equitable coverage of appropriate malaria treatment remains a high priority for the Nigerian government. This study examines the health seeking behaviour, patient-provider interaction and quality of care received by febrile patients of different socio-economic status (SES) groups. Methods: A total of 1642 febrile patients and caregivers exiting public health centres, pharmacies and patent medicine dealers were surveyed in Enugu state, South-East Nigeria to obtain information on treatment seeking behaviour, patient-provider interactions and treatment received. Socioeconomic status was estimated for each patient using exit survey data on household assets in combination with asset ownership data from the 2008 Nigeria Demographic and Health Survey. Results: Among the poorest SES group, 29% sought treatment at public health centres, 13% at pharmacies and 58% at patent medicine dealers (p < 0.01). Very few of those in the richest SES group used public health centres (4%) instead choosing to go to pharmacies (44%) and patent medicine dealers (52%, p < 0.001). During consultations with a healthcare provider, the poorest compared to the richest were significantly more likely to discuss symptoms with the provider, be physically examined and rely on providers for diagnosis and treatment rather than request a specific medicine. Those from the poorest SES group were however, least likely to request or to receive an antimalarial (p < 0.001). The use of artemisinin combination therapy (ACT), the recommended treatment for uncomplicated malaria, was low across all SES groups. Conclusions: The quality of malaria treatment is sub-optimal for all febrile patients. Having greater interaction with the provider also did not translate to better quality care for the poor. The poor face a number of significant barriers to accessing quality treatment especially in relation to treatment seeking behaviour and type of treatment received. Strategies to address these inequities are fundamental to achieving universal coverage of effective malaria treatment and ensuring that the most vulnerable people are not left behind

The costs of introducing artemisinin-based combination therapy: evidence from district-wide implementation in rural Tanzania

BACKGROUND\ud \ud The development of antimalarial drug resistance has led to increasing calls for the introduction of artemisinin-based combination therapy (ACT). However, little evidence is available on the full costs associated with changing national malaria treatment policy. This paper presents findings on the actual drug and non-drug costs associated with deploying ACT in one district in Tanzania, and uses these data to estimate the nationwide costs of implementation in a setting where identification of malaria cases is primarily dependant on clinical diagnosis.\ud \ud METHODS\ud \ud Detailed data were collected over a three year period on the financial costs of providing ACT in Rufiji District as part of a large scale effectiveness evaluation, including costs of drugs, distribution, training, treatment guidelines and other information, education and communication (IEC) materials and publicity. The district-level costs were scaled up to estimate the costs of nationwide implementation, using four scenarios to extrapolate variable costs.\ud \ud RESULTS\ud \ud The total district costs of implementing ACT over the three year period were slightly over one million USD, with drug purchases accounting for 72.8% of this total. The composite (best) estimate of nationwide costs for the first three years of ACT implementation was 48.3 million USD (1.29 USD per capita), which varied between 21 and 67.1 million USD in the sensitivity analysis (2003 USD). In all estimates drug costs constituted the majority of total costs. However, non-drug costs such as IEC materials, drug distribution, communication, and health worker training were also substantial, accounting for 31.4% of overall ACT implementation costs in the best estimate scenario. Annual implementation costs are equivalent to 9.5% of Tanzania's recurrent health sector budget, and 28.7% of annual expenditure on medical supplies, implying a 6-fold increase in the national budget for malaria treatment.\ud \ud CONCLUSION\ud \ud The costs of implementing ACT are substantial. Although drug purchases constituted a majority of total costs, non-drug costs were also considerable. It is clear that substantial external resources will be required to facilitate and sustain effective ACT delivery across Tanzania and other malaria-endemic countries

Phosphorus recovery as calcium phosphate by a pellet reactor pre-treating domestic wastewater before entering a constructed wetland

© 2019, Islamic Azad University (IAU). Horizontal subsurface flow constructed wetlands poorly remove phosphorus from wastewater, resulting in phosphorus levels above the required limits in constructed wetland effluents. Since a pellet reactor can recover phosphorus through calcium phosphate precipitation/crystallization, using it as a pre-treatment system prior to horizontal subsurface flow constructed wetland could be a sustainable solution for phosphate scarcity. The operational conditions required for phosphate recovery in a pellet reactor were evaluated and compared with the Visual MINTEQ version 3.0 with the aim of checking its suitability to simulate the pellet reactor removal efficiencies. Such conditions include the initial phosphate concentration, pH, [Ca]/[P] molar ratio and hydraulic loading rate. The results showed an increase in phosphate removal efficiency with increased initial phosphate concentration, pH, [Ca]/[P] molar ratio and decreased hydraulic loading rate. However, the model calculation gave higher removal efficiencies than experimental results due to its inability to take into account the system kinetics which is an important component in pellet reactor operation and its assumption that precipitation reactions take place at constant pH. The effects of carbonate on phosphate precipitation were also investigated, and the removal efficiency of 61.9% without carbonate was improved to 63.2, 64.3 and 66.4% with a carbonate concentration of 0.25 mM, 0.5 mM and 2 mM, respectively, at pH 9, initial phosphate concentration of 1 mM, [Ca]/[P] molar ratio of 1.5 and hydraulic loading rate of 57 m/h. Thus, the presence of carbonates in domestic wastewater is advantageous as it promotes calcium phosphate precipitation in a pellet reactor.status: publishe

Socio-economic analysis of constructed wetlands systems for hygienic sanitation in Tanzania

In Tanzania, as in many other developing countries, the great majority of people still do not have access to safe drinking water supply and hygienic sanitation. For institutions, such as schools and hospitals, where water supply is available, constructed wetlands system (CW) can provide hygienic sanitation. However, successful implementation of constructed wetlands in Tanzania is still hindered by to a lack of investment capital and lack of knowledge and commitment of users, responsible government institutions and international development agencies. Based on an evaluation of 5 constructed wetland projects, including an in depth socio economic analysis of 2 systems and a broader dynamic innovation system analysis of the water and sanitation sector in Tanzania, we provide insight in bottlenecks and opportunities for constructed wetland projects in Tanzania. This analysis shows that failure of constructed wetland projects is often due to the great discrepancy between the limited private and large societal net benefits. Socio-economic costs of diseases are not visible to decision makers and remain therefore unaccounted for. As a result implementation of hygienic sanitation systems fails due to unrealistic attempts at cost-saving by taking short-cuts in the implementation and maintenance. On the other hand, there are also very promising examples such as the constructed wetland system at the Ruaha Secondary School, whose sanitation was found to be technically, financially as well as social-economically successful