Wastewater: A valuable Resource

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As part of the 6th edition of Ask The Experts series themed: “Valorising the end-products of domestic and industrial wastewater treatment” organized on April 25th, 2023, by the African Water and Sanitation Association (AfWASA) in collaboration with the German- African Partnership for Water & Sanitation (GAPWAS), Justina Haihambo, Process Engineer Gammams Wastewater care Works at the City of Windhoek, central area of Namibia gave an insight into Windhoek’s direct potable reclamation.

Windhoek is located in Namibia, the driest country of sub-Saharan Africa, and is also the hub for the country’s economic, industrial, academic, commercial and political activities. The mission of the City of Windhoek is to enhance the quality of life of the population through efficient and effective municipal services and to improve water security. In the last housing and population census, the population of Windhoek was forecasted at 341000 people, but currently at a growth rate of 4.3%, is forecasted at about 441700 people. The annual water consumption of Windhoek is 27 000 000 m3/year, with an annual increase of about 3%. This, coupled with factors below, make the provision of water security of Windhoek uncertain:

  • Windhoek has the highest population growth rate that increases the water demand proportionally;
  • Windhoek is also synonymous for irregular or erratic rainfall patterns, which result in the lowest average rainfall, for annual rainfall of about 300 to 400mm. A low annual rainfall with the high annual evaporation of about 3000 to 3500mm;
  • Windhoek experiences regular drought and the ephemeral rivers that are closed to this city are fully exploited;
  • The perennial waters sources that are located closed to Windhoek are too far away. The Okavango River for example is 700km away, and the Atlantic ocean is about 3500km away.
  • The main perennial rivers are national borders originating in the neighboring countries, which means that the long- term agreement on water exploitation cannot always be guaranteed;
  • The portable water sources closed to Windhoek in close proximity have been fully harnessed.

The timeline of the potable water supply scheme of Windhoek has to be understood and considered in other to aid in understanding how wastewater is or has become a valuable resource toward water security. So, Windhoek was settled in 1840 partly because of the availability of groundwater from permanent hot springs. Until 1960, the city continued to heavily rely on groundwater from a well field for its water supply security, despite the construction of two small state-owned dams build-in ephemeral rivers in 1993 and 1958 respectively. So, meanwhile the population continued to rapidly increase, the city continued to experience regular drought in parallel. Consequently, all water resources at the time became depleted, which made the future of water security uncertain. Heavily relying on too small construction dams in ephemeral rivers and groundwater for water supply led to the fact that in terms of water, Windhoek became vulnerable; thus cementing the idea of unconditional water sources and supply and the idea of direct potable reclamation as well. This led to the construction of a direct potable reclamation plant in 1968 to argument the groundwater and the surface water supply, which at the time had become uncertain and unreliable. So, from 1970 to 1982, the state-owned supply system got extended in a three-dams systems.

From 1990 to present, Windhoek has been relying on what is known as the central area of Namibia supply scheme for its water supply or its potable supply needs. This supply scheme consists of the following:

  • First, the groundwater supply and the three-dams system, owned by a state- owned enterprise called NamWater, which is the country national water utility and bulk supplier;
  • Second, the reclaimed water or direct potable reclamation, with reclamation of potable water directly from sewage effluent that is produced and provided by a wastewater treatment plant called Gammams water care works wastewater treatment plant.

This direct potable reclamation was constructed at an initial capacity of about 4.8mega liters a day, which got increased over time. But at the end of its lifespan, in the midst of severe drought in 1997 and with lack of a sustainable water supply option at the time, it was decided to build a bigger plant at a capacity of 21 mega liters a day. Another Windhoek sustainable options to reduce the water demand, was the establishment of a semi- purified and irrigation supply scheme. This was established in 1993, with the construction of a dwell pipeline system to convey water from the old direct potable reclamation plant to sports fields of schools and establishment of businesses. This semi- purified water is also used at municipal wastewater purification plant for irrigation and general cleaning of equipment. This irrigation water supply scheme was established to decrease the Windhoek water demand by about 8%.

In another view, the current potable water supply scheme consists of:

  • Windhoek is indicated in the green square, central Namibia (See centre of Map 1 in attachment). So, the three- dams system that belongs to the state has the largest capacity; it consists of the Omatako dam (212 km from Windhoek) which is built in the Swakop river. Besides the rainfall, it gets supplemented by a scheme further up north and a state-owned scheme called Von Bach supply scheme from underground water; then the water is pumped into a canal called the eastern national water carrier located 430km away from Omatako dam, and which transports water to Omatako dam.
  • Then, the Von Bach dam is about 70km from Windhoek. So, water is pumped from Von Bach dam and is treated in the Von Bach purification plant; the water is then piped to Windhoek for supply. This water is finally blended with the direct potable reclaimed water and or the underground water for distribution.
  • The Swakoppoort dam (125km from Windhoek) is the largest one, which is built just downstream of the Swakop river.

Water reclamation or water reuse is known in theory as one of the main alternatives to reduce water demand. Therefore, Chart 1 in the presentation attached shows the annual consumption of water demand by source for Windhoek for the past 55 years. So, in general, the introduction of the direct potable reclamation means that the volume of water required from other conventional sources is reduced, and especially with introduction of the irrigation supply scheme in 1993. Direct potable reclamation also means that in normal metrological conditions, the groundwater can be preserved for use sustainably when necessary; for example, as was the case during the 2013 to 2019 drought, and more notable in 2019 when Windhoek experienced “the worst drought in 90 years” with the lowest average rainfall recorded.

Over the years or the 55 years, the water demand kept increasing proportionally with the growth rate; however, there were some notable reductions in water demands, and the weight of droughts in 1982-1983, 1996-1997, 2013-2019 were mostly attributed to water demand management.

Importantly, the ongoing success of direct potable reclamation can be attributed to correct practices and efficient operations for wastewater treatment. Therefore, if we don’t have efficient wastewater treatment in place, we don’t have direct potable reclamation. Grammans Water Care Wastewater treatment plant is an important component of the ongoing success of direct potable reclamation.

Grammans Water Care Works is a biological wastewater treatment plant that was built between 1959 and 1961 but commissioned in 1963. It was constructed with the initial capacity of 9 megaliters a day, which increased to 25 megaliters a day, its current capacity. It was designed to treat water from domestic origin. The industrial wastewater is diverted to another plant mainly to protect the direct potable reclamation plant from hazardous waste.

This allows to plan for Windhoek and the country, and Gammans serves as an important link in the water circle because it treats water, which is directly reclaimed for potable use, which serves partially towards meeting the water demand of the Windhoek potable water needs.

Chart 2 (see attachment) shows in- flow water into Gammans and then the supply water to the reclamation plant, and the product works into the reclamation plant. Of the effluent water received at Gammams, 75% is supplied to the direct potable reclamation plant. Of the water that is supplied, 85% is the direct potable reclamation plant intakes. of the intake, 92% is produced and then blended with other conventional sources for distribution.

With water reuse being recognized as the main alternative to reduce water demand or water consumption, Namibia as a water-stressed country must find ways to take advantage of all the drops of wastewater to increase the reuse potential. Therefore, another direct potable reclamation project was identified as one of the medium-term interventions to upgrade or improve water security. But for this project to be feasible, additional upgrades are required for the Gammams wastewater treatment plant and another municipal plant, in order to ensure that there is sufficient water at the right quality.

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Commercialization of Wastewater Sludge Beneficiation

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Sewage sludge disposal has become a costly and environmentally challenging matter that requires an innovative approach. Agriman (Pty) Ltd is a South African based company with an international footprint that provides a complete value chain solution for the handling, processing and beneficiation of wastewater sludge to a commercially marketable fertilizer.

Depending on existing infrastructure and processes employed at a wastewater treatment works (WWTW), Agriman has developed the ability to migrate upstream in the process line to perform and manage critical functions related to the digesters and dewatering of sludge that have a direct effect on sludge quality. By means of accelerated solar drying, sludge is dried and stabilized before disinfection and granulation takes place. Once granulated the product is then blended with conventional fertilizer feedstock to customer requirements for agricultural use, effectively transforming a hazardous waste into a registered organic fertilizer that is safe for agricultural use.

The environmental, economic and socio-economic impact of the traditional disposal methods of wastewater treatment works’ sludge is not a sustainable solution. Authorities are also being pressured by laws and legislations that are phasing out the disposal of sludge at landfill sites. Provided that dewatered sludge can be dried cost effectively at a specific WWTW,  Agriman can provide a sustainable long-term alternative that can be implemented on a large scale to safely handle and process sludge to an organic based fertilizer. The trend towards sustainable farming practices creates a high demand for commercially available organic fertilizers to supplement chemical fertilizers. This demand is currently not being met.  The potential to commercially beneficiate wastewater sludge to a registered and approved agricultural fertilizer on a global scale has been shown by Agriman as a model that is economically viable for wastewater authorities, the agricultural industry and sustainable development.

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Bisol Systems for Waste Water Management

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Bisol is a company started by a team of young civil engineers, and environmental enthusiasts, who are passionate about solving sewer problems and improving water sustainability. Their products are engineered and custom made to manage sewage and also recycle the sewage back to water for sanitary needs in short non-portable water that will be used for flushing toilets, cleaning the compounds, irrigation of the lawns, and farm irrigation.

The company works with institutions, private owners, and commercial businesses to promote wastewater recycling. The prospects is to be able to reach a large magnitude so that the company can improve sanitation in the region and water security.

Some of its products such as bio-toilets improve sanitation in schools and promote stability. There are also ultra-modern biodigesters that reduce and completely stop pollution, and a compact sewage recycling system that recycles sewage, treats and recycles water from the septic or biodigester and turns it into clean clear water.

Some of the systems presented in the attachment are Bisol’s own innovations and modifications. The company thus proposes custom- made solutions for different setups, through wastewater management consultancy team.

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Underground Sewerage Schemes: Last Mile Connectivity

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To keep up with the demands of rapid urbanisation, the Government of Tamil Nadu (GoTN) has accorded priority to implement Under Ground Sewerage Schemes (UGSS) in all the needy Urban Local Bodies (ULBs) through different financial schemes in a phased manner. The GoTN has made efforts to reach the ‘last mile’ with adequate and equitable sanitation and hygiene in ULBs of Tamil Nadu.  This paper aims to draw insights into the underlying factors and initiatives taken by the GoTN for the UGSS last-mile connectivity in the state.

Indeed, in a state like Tamil Nadu (TN), sanitation is essential for enhancing the quality of life and health and improving productivity. In this regard, GoTN has taken initiatives in UGSS implementation and also in Fecal Sludge Management (FSM) in a phased manner to reach last mile, which are broken down into three stages detailed in the full article attached herein: i) from 2000 to 2008; ii) from 2008 to 2017; iii) from 2018 to present.

Apart from the financial support initiatives to the households, dedicated Information, education and communication (IEC) programmes were also conducted in different parts of the state to educate the households on taking the service connections to avoid direct disposal of wastewater to the stormwater drains or the neighbouring lands.

For the ULBs which are not covered under the UGSS implementation scheme, a separate plan had been prepared on FSM for safely managed sanitation in the state. The timeline of legal and regulatory framework associated with FSM initiatives are given in the full article attached herein.

The use of water supply and sewerage connection deposits, interest-free loans, and taxes in Tamil Nadu suggests that long-term sustainability of sewerage systems can be achieved with policy commitment, effective project appraisals and citizen involvement. The efforts by GoTN on UGSS last-mile connectivity can be taken as a reference by other states to improve the last mile with inclusive sanitation. The major lesson learned from the UGSS implementation is that the selection of towns for the implementation has to be based more on public demand, their capacity to pay back the loan amount, and the financial capability of the ULB than on the readiness of the DPR for the project.

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The Yaounde Statement: AfWA Makes Recommendations for Non-Revenue Water (NRW) Management

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The Cameroon Water Utilities Corporation (CAMWATER) organized an international Symposium jointly with the African Water Association (AfWA) and some partners, including LACROIX Sofrel, Technolog SA, Liason, etc. This event took place from January 26 to 27, 2023, in Yaoundé, Cameroon, under the theme: “Financial Viability of Water Utilities in Africa: Control of Commercial Losses and Fraud on the Drinking Water Distribution Network”.

The aim was to boost the financial performance of water utilities, through the control of commercial losses and fraud on the drinking water distribution networks of water utilities. Specifically, it was intended to provide an overview of the specific challenges faced by some water utilitites, to share some success stories, including technical and technological solutions to control losses, and to exchange with financial partners on financing options to stem these losses.

The following participants attended this event : General, Commercial, Technical and Financial Directors, Directors of Planning and Operation of water utilities in Central Africa, West Africa and East Africa, especially the Cameroon Water Utilities Corporation (CAMWATER, Cameroon), the Chadian Water Company (STE, Chad), the Water Distribution Company of Côte d’Ivoire (SODECI, Côte d’Ivoire), Ghana Water Company Limited (GWCL, Ghana), National Water & Sewerage Corporation (NWSC, Uganda), Lilongwe Water Board (LWB, Malawi). Some municipalities and institutions such as the United Nations Development Program (UNDP), ministerial departments and other WASH stakeholders were also represented.

After two days of discussions with the sharing of practical experiences on the theme of the Symposium, some recommendations were formulated and organized into a Statement. Thus, the Yaounde Statement on Non-Revenue Water (NRW) identifies some lines of actions to help fight against water fraud and water losses through the use of technical tools, capacity building, financing and adoption of a regulatory framework and appropriate policies. This Statement was presented to the Cameroon Minister of Water & Energy, at the close of the Symposium.

The contextual adaptation of the suggested solutions and their implementation within the water utilities might contribute to resource preservation, improved revenues and prepare the way for financing the extension of services for the benefit of populations, including the most vulnerable segments.

For record, this Symposium was set a day after the final workshop for restructuring the Scientific and Technical Council (STC) of the African Water and Sanitation Association (AfWASA), still in Yaoundé, Cameroon, from 24 to 25 January 2023, and hosted by the Managing Director of CAMWATER, AfWASA Vice-President for Central Africa.

Download the Yaounde Statement here.

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Share Water No. 13

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The thirteenth issue of the African Water Association (AfWA) technical and bilingual magazine, Share Water, is now available. It provides solutions in terms of guidelines and tools likely to help manage the WASH businesses efficiently and mitigate the shortage of water supply, for improved access to sustainable water and sanitation services for all in Africa.

Among these solutions, the water safety plan (WSP) approach is widely recognized as the most reliable and effective way to consistently manage drinking-water supplies to safeguard public health. Since the introduction of WSPs in the third edition of the WHO Guidelines for Drinking water Quality (GDWQ) and the International Water Association (IWA) Bonn Charter for Safe Drinking Water in 2004, a significant number of water suppliers have implemented WSPs, and many governments are actively promoting their implementation and/or inclusion in national legislation.

Some benefits of WSP implementation include the promotion of public health by continuously assuring safer drinking-water for consumers, the setting up of a proactive (rather than reactive) framework for managing drinking water quality, the early identification of new/increased risks-incidents, the in-depth systematic evaluation of water systems, and much more…

 

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Zoom : des équipements pour l’approvisionnement en eau et le traitement des eaux usées

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Les solutions du groupe AVK interviennent à ce jour dans tout le processus de l’eau ou cycle de l’eau, du pompage au traitement, en passant par le réseau de transfert, de distribution et de traitement des eaux usées. Les équipements fabriqués et commercialisés rentrent dans la gamme des vannes à opercule (jusqu’à 2500 de diamètre), vannes à papillons (jusqu’à 3600 de diamètre) et vannes de régulation ou intelligentes, qui permettent de stabiliser une pression ou un débit en fonction de la consommation des abonnés. Ces vannes permettent de suivre le débit journalier et le débit nocturne, pour ne pas rester sur une pression en aval de 4 à 5 barres sur toute l’année alors que le tirage est à forte consommation. Des vannes de branchement avec système de clapet sont également disponibles, et l’entreprise dispose à ce jour d’une des gammes les plus larges de robinetterie et accessoires de canalisations pour l’eau potable ; toutefois, elle ne fabrique pas les pompes.

La vanne papillon est adaptée aux gros diamètres, pour une meilleure gestion de l’encombrement et du regard. Il existe une gamme dont les matériaux sont adaptés aux liquides agressifs ou eaux usées. Les vannes murales et guillotines sont quant à elles utilisées pour les stations d’épuration. La gamme de protection incendie pour sa part, devra être placée sur des poteaux incendie dans les villes afin d’assurer la sécurité des habitants.

La vanne opercule est la plus utilisée dans les réseaux d’eau en Afrique ; bien qu’assez banalisée car enterrée (l’appareil est souvent invisible), elle sert à sectoriser un réseau dans le cadre de la procédure pour déterminer l’Eau Non Facturée (ENF). Si la vanne n’est pas étanche, toute la logique de calcul est fausse. D’où la problématique de la qualité des produits installé sur les réseaux, car très souvent les vannes ne fonctionnent pas et ne sont pas étanches.

Le logiciel AVK Assist peut être installé sur I-pod ou Android pour lire les données des vannes connectées qui disposent d’un code-barres ; par ce moyen, il est possible de géolocaliser l’emplacement de la vanne. Il existe également des fiches techniques et des petits logiciels pour calculer les débits. La vanne intelligente comprend un système de capteurs qui donne à l’exploitant des informations sur la manipulation de la vanne de façon instantanée, et celle-ci ne peut plus être manipulée à l’insu de l’exploitant. Pareillement, cette technologie permet de signaler la manipulation du poteau incendie par une personne non autorisée. Cette technique innovante s’avère très utile pour lutter contre le phénomène de l’Eau Non Facturée, i.e. l’eau produite mais non facturée à l’abonné.

AVK impose sur le cycle de l’eau les exigences qu’elle s’est fixée pour la gestion du gaz. Il y’a un écrou de manœuvres complètement serti englobant dans l’opercule en fonte et entièrement vulcanisé. Il n’y a aucun mouvement, ni vibration entre l’écrou et l’opercule, donc aucune corrosion. Il existe un concept où l’écrou est simplement positionné et un mouvement continuel peut être noté. Aussi, après quelques mois ou quelques années, il y’a un phénomène de vibration et donc de corrosion.

AVK est l’une des seules sociétés qui fabrique le caoutchouc (polymère) utilisé pour ses équipements. Une vanne opercule c’est de l’EPDM compatible à l’eau potable. C’est dire que AVK possède la maîtrise qualitative du processus de fabrication, qui tient compte de la norme européenne EN 681, relative à l’élasticité du caoutchouc et la rémanence (capacité à pouvoir s’écraser quand on ferme la vanne et à retrouver sa forme initiale quand on ouvre la vanne). La certification allemande GSK permet à AVK de garantir la qualité du revêtement époxy sur la vanne. Il existe plusieurs critères de contrôles non destructifs qui permettent de garantir la longévité du revêtement époxy sur les équipements, ce qui empêche toute corrosion de la vanne, même après dix (10) ans d’utilisation. En tant que garantes de la qualité de leurs réseaux, les sociétés d’eau gagneraient à tenir compte de ces certifications.

Le concept de vannes à brides peut être multiplié en différents types de connexion. Même si la vanne opercule est le nouveau produit lancé, il existe plusieurs pipes en PEHD dans la sous-région. Il s’agit d’un équipement dont les 02 embouts sont très manchonnés, sans aucun boulon à serrer et sans couples de serrage à respecter ; il suffit de souder les tubes PEHD sur les embouts qui sont déjà sertis et testés en usine. L’avantage du PEHD est la garantie d’un niveau zéro de fuites, car le polymère peut être soudé.

Les bouches à clé vont de pair avec les vannes, car elles constituent le point d’accès de la vanne par lequel il est possible de faire de la recherche de fuites grâce aux logeurs, entre autres systèmes de qualité, qui permettent d’écouter le retour du réseau. À la suite des vols de fonte et à la demande des clients, AVK s’est orientée vers des matériaux composites qui sont recyclables, économiques, non corrosifs, ne peuvent pas être volés et consomment moins d’énergie afin de répondre aux exigences énergétiques actuelles. Une nouvelle bouche à clé en tête fonte, tout en composite (tête ronde, marquage hexagonal, couleur dédiée, numérotation, etc.), qui peut être réhaussée pour s’ajuster sous la chaussée au passage des véhicules a été lancée. En effet, l’un des problèmes récurrents est l’écrasement de la chaussée par les gros porteurs (véhicules à fort poids), qui laisse en saillance la bouche à clé ; elle reste donc en hauteur par rapport à la chaussée. La solution proposée va suivre le mouvement de la chaussée, et assurer une continuité constante entre la tête de la bouche à clé et la route, qui facilitera la manipulation de la vanne au cours des années à venir dans un souci de durabilité. À la demande des clients, elle est en cours de développement et de vente en Afrique.

L’origine de l’ENF peut être les fuites dans les vannes. Aussi, des équipements de réparation de conduite revêtent une importance majeure. Il s’agit des solutions ou manchons toute pression, tout matériau (pipe en PVC, PHP, acier, etc.) et tout type de pression (jusqu’à PN=40) qui permettent de réparer les canalisations ou conduites en charge sans couper l’eau. Les informations sur le type de conduite, le diamètre extérieur et la pression permettent de fabriquer des manchons dédiés pour résoudre rapidement et à faibles coûts les problèmes de fuites, évitant ainsi les coupures d’eau intempestives.

L’emboiture de deux (02) canalisations en PVC ou en fonte qui ont des fuites peut également être réparée. Les avantages comprennent la simplicité de la réparation qui est définitive et garantit l’étanchéité sur le long terme, sans coupure de tube, sans déterrer la canalisation et sans coupure d’eau afin de ne pas perturber les utilisateurs finaux lors du processus.

 

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A Non-Intrusive Technology for Network Performance Control

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The ultrasonic flowmeter is a tool for network performance control and preventive maintenance in handheld and fixed station. The principle of operation is the set of two (02) sensors on the same side of the pipe with sending of a wave on the side, which is reflected on the pipe that arrives on the second sensor. The 2nd sensor does the same thing and sends a signal which will be recovered by the other sensor. Depending on the direction of the flow rate and the speed, a difference in travelling time will be noted, which allows to measure the speed. As it applies to any measuring tool, the external diameter of the pipe or the wall thickness and the nature of the material should be set up.

The advantage of the ultrasonic flowmeter lies in its non-intrusive technology. It adapts itself to the environment and places itself on the pipe, without the need to take over the pipe or cut it. Moreover, it is not necessary to carry out important works for the setting up of the flowmeter. Its sensors allow it to adapt to different types of pipes, as they adjust to the pipe and can be installed on all types of networks, mainly in metal, non-metal network, PVC, PE, concrete, cement, asbestos, etc., ranging from 25 to 4700 in diameter.

The measurement is bi-directional and without loss of load because there is no contact with water. Sensors can be placed in different locations and require little space depending on the diameter and the nature of the material. The spacing between the sensors does not have to be very large.

The handheld tool is a small object that can be held in the hand, depending on the manufacturer and the pair of sensors, with a system that allows sensors to be tied to the pipe.

The fields of application are quite diverse. The ultrasonic flowmeter allows to control the performance of networks, in addition to or as an alternative to fixed sectorization, which is quite developed in the world. The performance of a drinking water network is controlled by measuring its flow rate, especially the night flow rate. The sectorization allows to identify the leaking sectors and to prioritize the research areas on which to carry out priority actions of leakage research, frauds, and network renewal, etc.

The watertight valves allow further reduction of the sectors through valve operations, changes in hydraulic sectors during the night, over several days or instantaneously depending on the research zones. They also allow to quantify the losses on the night flows rate, and then to carry out a ratio of the losses to check the performance of the network in the concerned areas to initiate or not corrective actions. They are further used to check the sectorization in place, especially the large meters and flowmeters that are already in fixed stations, which is a strategic focus for operators of water networks. The control is performed upon insertion, thanks to the presence of a fixed sensor that needs to be handled using an ultrasonic flowmeter, which can be an electromagnetic flowmeter, a mechanical meter, etc.

Some customers use it to check the large meters of big consumers before they validate the metering, given the financial impact of under-metering on large consumers. Data from the checking of fixed sectorization meters is used for the analysis of good or bad operation of a network. Failure to measure from the fixed meter has an impact on the operation and performance of networks. To check the pump flow rates, it is necessary to set the sensors on the pipes at the pump outlet and validate the nominal flow rate of the pump, i.e., identify if the pump is operating properly or if there is a need for maintenance.

It can be used upstream of works when defining the profiles of consumption, of distribution, of a suppressor, or the profile for the renewal of pipes. It is possible to set the device over several days to record the minimum, maximum and average flow rates, which will allow the correct dimensioning of works, i.e., avoiding having pipes or conduits that are too large or too small and using a suppressor adapted to the area.

Some images in the presentation below show the successive launch of four pumps to reach the desired flow rate in the drawdown to make the controls, and different examples of implementation. In the first example, the fixed insertion probe sends its data through a remote transmission system to the customer’s supervision software. The customer’s leak detection team had performed three unsuccessful researches for 20m3 of leaks in a specific area. Back to the starting point, there was a 20m3 difference between the handheld ultrasonic flowmeter that was set up and the insertion probe. The drift of insertion probe that occurred, resulted in a miscalculation of a measurement point and consequently a loss of operation due to the time spent to look for leaks where there were none.

Regarding the comparison with electromagnetic flowmeters, the connection with the flowmeter in place can sometimes run smoothly, but we can also observe electromagnetic interference defects on the electromagnetic meter that lead to a metering defect and a corrective action by the customer. In one of the cases encountered, one of the electromagnetic meters had got a large leakage rate, and the doubt of leakage was persisting. In fact, there was a 4 to 5 cubic meter difference that made it impossible to find the location of the leak, as the customer could not find their way around. The laying of an ultrasonic flowmeter allowed to detect the problem quickly. Example 2 (see presentation) is a DN300 stainless steel pipe on site where a pump flow rate had to be checked. The more the pipe will be larger, the greater will be the spacing between sensors. In case of no fixed flowmeter, it is possible to use the handheld ultrasonic flowmeter as a starting point to carry out checking for leaks, fraud and validate the proper functioning of a network. As a reminder, the minimum flowmeter is connected to the existing network.

That handheld measurement tool can be used by different departments: the distribution, performance and network department can be interested in leakage research feature, flow rate measurement feature and linear loss index ratio; production and maintenance department can use it to validate pump flows rate amongst other items that leaves the factory; metrology and metering department for the checking of fixed station meters; engineering offices and works department for the realization of hydraulic profit before works (e.g. modification of pipes, suppressors…) and quality department to validate performance of the network, etc.

Framework for the use of fixed ultrasonic flowmeter may varied. The handheld tool is multi-service and adapts itself to the environment. The use of fixed station is more restrictive, given the need to be tied to a point. Sensors are the same for handholding and fixed station. The difference lies in the unit, which will be fixed and close to the pair of sensors for the recovery of data from sensors and communication link with the remote transmission system for retransmission to a supervision software. The interest is obvious when it comes to large diameters of minimum DM400. Under that size, it is possible to use a fixed station to handle a fragile pipe, that one does not want to touch (the interest here lies in the non-intrusive side and the absence of important works for laying the equipment). However, it is suitable to be rigorous on the straight lengths to be respected for a better long-term precision.

The ultrasonic flowmeter is used for both drinking water and wastewater because the flow rates of condensate pumps are also checked by sanitation departments. The checking of flow rate pressure pumps with fixed station is also carried out for wastewater. To achieve the accuracy of wastewater measurement with the ultrasonic flowmeter, the pipe must be full. Sensors can be buried and immersed for a long time at fixed points. Pumps with inverters allow flow rate measurements to be tested even when water is loaded.

SEWERIN is a German manufacturer of equipment for improving the performance of water systems, mainly water leakage detection and Non-Revenue Water (NRW) improvement.

 

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Smart Water Management by Xylem’s Digital Solutions

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The 90th meetings of the African Water Association (AfWA) Scientific & Technical Council (STC) were held in Abidjan, Côte d’Ivoire from November 21 to 24, 2022, under the theme “Innovative Systems, Approaches and Tools to Accelerate Access to Sustainable Water and Sanitation Services for All”. A series of three technical conferences were given during STC Day 1, including one on Smart Water Management by Mr. Samba GUINDO, Regional Sales Manager – West Africa at XYLEM Côte d’Ivoire.

XYLEM is a manufacturer and supplier of innovative technologies in the water sector i.e. pumping systems (multistage, self- priming, end suction…), aeration equipment, flow meter, smart meter, etc.

Xylem’s Digital Solutions help customers gain capabilities in three key areas across their network.

  • Increase the ability to visualize the utilities’ entire water system by providing enterprise-level network transparency to justify expenditures, and prepare for challenges before they become failures;
  • Optimize that system with deeper insights and actionable, data-informed recommendations to improve their systems in real-time, and make better use of inputs and personnel;
  • And deliver greater asset reliance and resiliency, and increasing safety for the community and your people

Xylem digital ecosystem creates an information-centric and connected environment. As the workforce is connected to each other ,they are now connected to physical assets and the environment. Networks of sensors installed through supply, collection, treatment and distribution operations will monitor conditions in real time. Data and information will available via the cloud and hand-held devices anywhere, anytime. Beyond instantaneous process control, big data analytics provides the unique opportunity to explore Decision Intelligence. There are four major technological elements to Industry 4.0: i) Industrial Internet of Things (IIoT), ii) Cloud Computing and Edge Computing, iii) Big Data Analytics and iv) Artificial Intelligence and Machine Learning.

Xylem’s digital solutions fall under big Data Analytics and artificial Intelligence and Machine Learning. Machine learning enables systems to take prescriptive actions based on data-driven predictions. Automation has already replaced routine, manual tasks with higher value. Machine learning and artificial intelligence enable decisions and actions to be taken preemptively in response to changing conditions.

In-situ IIOT devices with edge computing will detect, control and provide visibility on events i.e. level rises, pressure changes, changing water quality and wastewater loading, loss of flow, off-spec effluents, etc.

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Six takeaways identified by the All Systems Go Africa symposium for accelerating progress in the WASH Agenda across the African continent

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This three-day All Systems Go Africa symposium was convened by IRC, in collaboration with UNICEF and the Government of the Republic of Ghana who also hosted the event. Between 19 and 21 October 2022, the event brought together over 250 participants, with delegations from 25 African countries, at the Kempinski Hotel. Participants comprised political leaders, professionals, government officials, academia, NGOs, private sector, donors and regional institutions – including the African Ministers’ Council on Water (AMCOW), the African Development Bank (AfDB), the African Water Association (AfWA), and the African Civil Society Network on Water and Sanitation (ANEW). The symposium examined the lessons learned from the review of progress and the critical changes needed to achieve the water, sanitation and hygiene targets in Africa. The key takeaways from this workshop are available here.

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