Faecal contamination across the lettuce value chain was assessed in Maputo, Mozambique. Escherichia coli was used as an indicator of faecal contamination, with concentrations ranging from 3.4 to 5.7 log units/100 ml in groundwater, river water and partially treated wastewater. Municipal tap water used to wash lettuce heads in the markets had lower than 1 log unit/100 ml. Irrespective of the source of irrigation water, the lettuce heads were contaminated throughout the value chain, with concentrations ranging between 6.5 and 7.8 log units/100 g. Interventions and awareness raising should be applied at every stage of the value chain.

Experiments were conducted to evaluate the possibilities of using treated wastewater for the production of unreinforced concrete blocks. Compressive strength, water absorption and morphology tests of concrete blocks, produced from different makeups of mixing water, drinking water, drinking water spiked with ammonium and phosphate, and the effluent of the city’s wastewater treatment plant, were evaluated. Results showed that the compressive strength of blocks manufactured using treated wastewater was as high as of the blocks produced using drinking water. Ammonium, phosphate and chlorine were found not to have a negative effect on the strength of the blocks. Water absorption tests confirmed the results of the compressive strength, as lower humidity was found in cases of higher strength. In the process of cement hydration, crystals of calcium silicate and calcium hydroxide were observed by morphology tests. From the variability in the results, it could be concluded that the quality of the mixing water was not the only factor that influenced the strength of the unreinforced concrete blocks. The observed differences in strength could, for example, also be attributed to the manufacturing process.

This review identifies the potentials and constraints of using (partially) treated or blended wastewater for irrigation in order to assess the potentials in the context of cities in sub-Saharan Africa, specifically Maputo, the capital of Mozambique. Less than 5% of the wastewater produced in the region is being treated. Nonetheless, untreated, partially treated, and/or blended wastewater is extensively being used for agricultural purposes. Despite the last updated WHO 2006 guidelines for ‘wastewater use in agriculture’, authorities only consider the different water quality parameters at the point of use. Other aspects such as irrigation type, crop management and post harvesting practices, which clearly influence the contaminant log reduction, are simply ignored. Those parameters, however, are considered alternatives to a classic contaminant log reduction, which may be very beneficial for developing countries. In a more holistic approach, trade-off is favoured between the required water quality for irrigation, use of affordable treatment technologies, and adequate post-harvest strategies to reduce the current health risks to acceptable levels. Such a trade-off makes use of multiple barrier approach, whereby wastewater treatment and critical point barriers throughout the supply chain are combined. Thus, there is a long way ahead to achieve proper water reclamation for productive use; the current paradigm has to change. Current restrictive guidelines are unrealistic given current practices, and approaches more appropriate to the location's situation still need to be developed. A multiple barrier approach in combination with master planning is recommended to consider wastewater treatment and critical point barriers throughout the supply chain.

The increasing world population and growth of industrial development lead to growing water scarcity that, combined with deficient sanitation services, represents serious challenges, particularly in regions like sub-Saharan Africa. Water reclamation is a promising approach to reduce water scarcity, serving as a driving force for better sanitation services and protecting the environment by treating sewage and redistributing for the benefit of other water-dependent applications (e.g., industries). This paper aims to give an overview of the global trends on water reclamation, with a focus on industrial use, and to derive lessons for implementation of water reclamation projects in sub-Saharan Africa. Findings show that extensive experience exists in technology and management practices that can allow successful implementation of water reclamation projects in the region. Under the conditions of deficient sanitation services and low levels of technical expertise, the main challenge is to develop a framework that can facilitate the integration of social and technological methodologies and help in introducing water reclamation in water allocation planning, including the development of specific legislation for industrial water use and disposal.

In Maputo, the capital of Mozambique, nitrate concentrations above 250 mg L??1 in groundwater have been reported. This happens due to the widespread use of latrines and septic tanks that allow for constant infiltration of its content into the soil and eventually to groundwater sources, a situation that is widespread in the Global South and represents a serious threat for human health and for the environment. This is a reflection of limited access to safe and adequate sanitation services, which the local authorities have set to improve in the forthcoming decades with a recently commissioned city-wide sanitation masterplan serving as a basis for the works. In this article, we aimed at understanding whether the infrastructure projected in the masterplan would lead to a reduction of nitrogen reaching groundwater. Currently, according to our calculations, almost 500 onnes of nitrogen reach the city's groundwater sources each year, with the masterplan potentially resulting in a 14% reduction, a small reduction due to its reliance on maintaining and expanding fecal sludge services, without considering investments to improve domestic systems (e.g., construction of contained systems). An alternative, not presented in the Masterplan and put forward by the authors, could be the construction of simplified sewers in two of the city's most densely populated neighborhoods, with a potential 29% reduction in nitrogen reaching groundwater.

In the context of the present work it is hypothesized that the condition of a PVC push-fit joint can be obtained from the analysis of the joint's gap width. A perfectly jointed and aligned pipe, for example, should have a constant gap for the complete pipe diameter while a bent joint should show variations of the gap width with the diameter. Therefore, laboratory tests were performed to test the applicability of ultrasound in the assessment of PVC push-fit joints which are ubiquitously used in the Netherlands. In those tests the potential of ultrasound to detect changes in geometrical alignment of PVC pipes was evaluated using a specially built metallic loading frame. This frame supported two 2-meters ø315 mm PVC pipes connected with a push-fit joint. This pipe could be kept in horizontal position or be bent up to an angle ofca. 5 degrees in 11 uniform steps. Results show that when two pipes have a perfect alignment (zero degrees angle between the pipes) the tested ultrasound tool describes quite adequately the real situation and gives good information about the joint's real condition. However, when an angle is imposed on a PVC joint the ultrasound results are not consistent with reality. This discrepancy is probably due to both longitudinal and shear ultrasound waves echoing back to the transducer from the PVC wall. The creation of both longitudinal and shear waves occurs when an angle between the ultrasound transducer and the object being studied exists. This factor is known to complicate the resulting ultrasound scans and the interpretation of the results. In conclusion, for this application ultrasound inspection is vulnerable to changes in geometrical alignment of assessed pipes. Even being unanimously considered as a potential technique for the inspection of polymeric pipes, ultrasound tool is not capable of giving results that permit accurate detection of all known failure mechanism of joints.