Time and motion assessment of pit-emptying operations in Kigali, Rwanda

To ensure sanitation for all by 2030, fecal sludge collection services in low-income urban areas with no sewer connections need improvement. One of the major issues is the gap between low-income household's willingness to pay and the cost of emptying services in low-income areas. One way of lowering the cost of these services is through process optimization. In this regard, we conducted a time and motion study to better understand the bottlenecks associated with the collection of fecal waste from different types of on-site sanitation facilities. Our results show that emptying pit latrines, which make up 53% of the market for emptying services in Kigali, takes twice longer than emptying septic tanks. 33% of households that requested the service were located in an informal settlement with no access to road and could only be served by a semi-mechanized method which required use of barrels, and a portable pump. In general, interventions related to minimizing trash disposal in pits and septic tanks can go a long way in making the emptying process more time and cost-efficient. Additionally, developing effective and efficient pumping technologies that are suitable for use in inaccessible areas should be prioritized.

Onsite sanitation and quantification of faecal sludge in the city of Yaoundé in Cameroon

This study aims to describe the onsite sanitation and the quantification of faecal sludge in the city of Yaoundé. The city of Yaoundé, The population of Yaoundé City is about 3.1 million inhabitants in 2018 , will reach 4.7 million in 2030 with an average annual growth rate of 3.5%. The city of Yaoundé is dominated by an autonomous sanitation system which is used by 99% of households. Domestic wastewater of the city is mainly dealt through on-site sanitation systems represented by septic tanks, traditional pit latrines, ventilated improved pit latrines, etc A survey was carried out among 1100 households in the city of Yaoundé. The choice of household to be surveyed was made according to the stratified sample method. It is reviewed, the methods of quantification of existing used sludge, in order to choose a method adapted to the context of the city of Yaoundé. Several criteria are analyzed to access to the sludge produced by households: the existence or not of roads, their state of deterioration, the types of sanitation structure, the position of the structure in relation to the waterways, etc. Among the methods for quantifying the sludge explored, we found that "the specific production method" is more adapted in the context. But this method has been revised in order to integrate the analyzing elements on the accessibility of the facilities. The application of the method used has been done on 120 pit emptying during two months (june and july 2018). The choice of these pits as been done hazardly on the potential of 600 pit emptying in the city of Yaoundé during this period. The accumulation rate of faecal sludge in the city of Yaoundé is of 0.356 l/hab/jour for septic tanks and of 0.21 l/hab/jour for pit latrines. It equally varies according to the luxury of the habitat. At the scale of the city, in 2018, 41% of single pits and 84% of septic tanks can be drained by trucks. The interval between two emptying is of 7 years for septic tanks and 10 years for pit latrines. Finally, the city of Yaoundé produces 2018, 283 175 m3 of faecal sludge per year, thus 51.7% can be drained by truck (146 514 m3), either 401 m3/jour. Only 52.4% are collected and (210 m3/jour) and sent-on the site of unloading of NOMAYOS. La présente étude porte sur le traitement sur l’assainissement dans la parcelle et la quantification des boues de vidange dans la ville de Yaoundé. La population de la ville de Yaoundé 3,1 millions d’habitants en 2018, atteindra 4,7 millions en 2030 avec un taux de croissance moyen annuel de 3,5%. La ville de Yaoundé est dominée par un système d’assainissement autonome qui est utilisé par 99% des ménages. Les eaux usées domestiques de la ville sont principalement traitées par des systèmes d'assainissement autonomes représentés par des fosses septiques, des latrines à fosse traditionnelles, des latrines à fosse améliorée ventilées, etc. Une enquête a été effectuée auprès de 1100 ménages de la ville de Yaoundé. Le choix de ménage à enquêter a été faite selon la méthode stratifiée. Il est passé en revue, les méthodes de quantification des boues de vidange utilisées existantes, afin de choisir une méthode adaptée au contexte de la ville de Yaoundé. Plusieurs critères sont analysés pour évaluer l’accès aux boues produites par les ménages : l’existence ou non de voirie, leur état de dégradation, les types de l’ouvrage d’assainissement, la position de l’ouvrage par rapport aux voies d’accès etc. pour la quantification des boues de vidange. Parmi les méthodes de quantification des boues de vidanges explorées, nous avons trouvé que « la méthode production spécifique » est plus adaptée au contexte. Mais cette méthode a été revue afin d’intégrer les éléments d’analyse sur l’accessibilité des ouvrages d’assainissement. L’application de la méthode retenue a été faite sur 120 ouvrages d’assainissement vidangés entre Juin et juillet 2018, choisis au hasard sur le potentiel de 600 ouvrages vidangés dans la ville de Yaoundé pendant cette période. Le taux d’accumulation des boues de vidange dans la ville de Yaoundé est de 0,356 l/hab/jour pour les fosses septiques et 0.21 l/hab/jour pour les latrines. Il varie également en fonction de standing de l’habitat. A l’échelle de la ville, 41% des fosses uniques et 84% des fosses septiques peuvent être vidangées par camion. L’intervalle entre deux vidanges est de 7 ans en moyenne pour les fosses septiques et 10 ans pour les latrines. Au final, la ville de Yaoundé produit en 2018, 283 175 m3 de boues de vidange par an, dont 51,7% peuvent être vidangés par camion (146 514 m3), soit 401 m3/jour. Seuls 52,4% de la quantité vidangeable, sont collectés en 2018 (210 m3/jour) et acheminés sur le site de dépotage de NOMAYOS.

DESTRUCTION OF DYES IN WASTES OF TEXTILE PRODUCTS

The results of wastewater treatment of textile enterprises in the electrolyzer with insoluble anodes and separation of electrode spaces with an inert membrane are presented. The influence of time, current density, concentration of sodium chloride, the initial concentration of dyes on the process of electrochemical destruction is determined. The developed technology makes it possible to ensure the effectiveness of the destruction of dyes and organic substances, which is necessary to obtain water quality that meets the standards for discharge into the municipal sewage system and reduce the cost of water treatment due to the lack of reagent facilities, septic tanks and dewatering equipment.

Moving up the sanitation ladder: latrine promotion and household decision-making in Viet Nam

We examine the relationship between promotion activities and sanitation decisions in the context of a program in the Mekong Delta that encouraged households to switch from fishpond latrines to septic tanks. Before and after the campaign, we surveyed households and promoters. Economic variables were important determinants of septic tank adoption, but whether or not the decision was woman-led and familiarity with the promoter were strongly predictive as well. Controlling for the pre-existing household decision-making structure, women were more likely to lead the sanitation decision if a promoter spoke to them rather than a male householder. Our household-based findings on the importance of promoters were supported by a supplementary analysis of sales. We found that promoters who were older, trained, and educated were more successful in selling septic tanks. Taken together, these findings highlight the importance of gender equity and trust in the promoter for encouraging last-mile households to invest in new health technologies.

Safely Managed On-Site Sanitation: A National Assessment of Sanitation Services and Potential Fecal Exposure in Indonesia

Sustainable Development Goal target 6.2 calls for universal access to adequate and equitable sanitation, setting a more ambitious standard for ‘safely managed sanitation services’. On-site sanitation systems (e.g., septic tanks) are widely used in low- and middle-income countries (LMICs). However, the lack of indicators for assessing fecal exposure risks presents a barrier to monitoring safely managed services. Furthermore, geographic diversity and frequency of disasters require a more nuanced approach to risk-informed decision-making. Taking Indonesia as an example, the purpose of this paper is to provide insights into current status and practices for on-site sanitation services in the contexts of LMICs. Using a dataset from a national socio-economic survey (n = 295,155) coupled with village census (n = 83,931), we assessed (1) household sanitation practices across Indonesia stratified by city-level population density and meteorological factors, (2) factors associated with septic tank emptying practice, and (3) inequalities in potential fecal exposure as measured by population density and WASH access by wealth quintile. We found a high reliance on on-site sanitation facilities (80.0%), almost half of which are assumed to be ‘uncontained’ septic tanks and one in ten facilities discharging untreated waste directly into the environment. The most densely populated areas had the highest rates of septic tank emptying, though emptying rates were just 17.0%, while in the lowest population density group, emptying was rarely reported. Multivariate regression analysis demonstrated an association between flooding and drought occurrence and septic tank emptying practice. Higher groundwater usage for drinking among poorer households suggests unsafe sanitation may disproportionally affect the poor. Our study underscores the urgent need to strengthen the monitoring of on-site sanitation in LMICs by developing contextualized standards. Furthermore, the inequalities in potential fecal exposure require greater attention and tailored support mechanisms to ensure the poorest gain access to safely managed sanitation services.

DETERMINATION OF CONTAMINATION DISTANCE FOR BOREHOLES IN OKIGWE ZONE, IMO STATE NIGERIA

Groundwater contaminants in Okigwe zone in Imo state made up of six local government areas were investigated. Four (4) groundwater samples were collected from each local government area. This amounted to twentyfour groundwater samples. These samples were collected randomly from sites close to septic tanks and to avoid contamination from tanks, the samples were collected at the well head, before water enters into storage tanks. The samples were stored in a sterilized 250 ml bottles and then taken to the laboratory for analysis. The chemical parameters were determined using a HA-CH 44600-00 and using standard methods as contained in Chessbourgh (2014). These samples were refrigerated and analyzed within 24 h. All plastics and glass wares utilized were pre-washed with detergent water solution, rinsed with tap water and soaked for 48 h in 50% HNO3 then rinsed thoroughly with distilled- deionized water. These results were used to ascertain the levels of groundwater contamination in Okigwe zone. An equation was generated from the chemical parameters using SPSS and E-view softwares to estimate the minimum allowable distance for locating borehole from sources of contamination in Okigwe zone in Imo state Nigeria. The minimum allowable distance calculated for groundwater from sources of contamination (septic tanks) is 15.81meters.