GIS Oriented Service Optimization Tool For Fecal Sludge Collection

In developing countries most of the urban dwellers don’t have access to sewer system. People are mostly using “onsite” systems such as septic tanks or pit latrines that need to be emptied periodically, as the densely built urban environment won’t allow new pits to be dug every time they fill up. In the conventional fecal sludge collection systems, authorities are collecting the sludge from house to house and dump on the plant. Fecal sludge collection system is different from traditional vehicle routing and even from solid waste collection system in terms of dynamic collection points, urgency of getting the service and diversity of demand. Due to those vibrant factors authorities are facing proper networking and management problems. This research describes algorithms that can accommodate constraints and prioritized customers who need immediate service. The GPS log data of the fecal sludge collection truck that maintained by Nonthaburi Municipality, Thailand has been considered as the base data during the development of this application. Spatial analysis has been done using Geographic Information Systems (GIS).Tabu Search has been implemented in order to optimize. Basically two algorithms were produced for assisting fecal sludge collection systems. First algorithm was able to produce multiple trip for each vehicle if required considering all the customers having equal priority, time window. The second one was able to perform optimization that can accommodate priority along with the first one. Input for the algorithms were very simple; distance matrix having distance between each customers and plant, customer order with latitude, longitude, order unit, time window, priority and vehicles with capacity. Algorithms were able to produce better result than the actual operation or even from shortest path algorithm in term of distance. After optimization, efficiency of the algorithms were tested with the actual travelling distance. Travelling distance were reduced to half compare to actual cost and it ensured maximum utilization of vehicle capacity by allocating maximum number of customers in each route

Factors influencing physicochemical characteristics of faecal sludge in Phnom Penh, Cambodia

Comprehensive knowledge of faecal sludge characteristics is needed for sludge management planning, but it is lacking for the city of Phnom Penh, Cambodia. Thus, this study characterised physicochemical properties of faecal sludge from households in Phnom Penh and related these to sludge containment unit type, unit age, connectedness to the urban drainage network, type of wastewater captured, watertight containment units, number of users, and emptying practices. In total, 194 faecal sludge samples collected during containment unit emptying were analysed for physicochemical parameters. Information on containment units was collected in a survey of emptiers and users. Mean values of faecal sludge chemical parameters were found to be slightly lower than previously reported values for low-/middle-income countries, whereas physicochemical properties were within similar ranges. The main factor influencing organic matter content in faecal sludge was containment unit connection to the urban drainage network, whereas emptying practice and capture of only blackwater affected nutrient levels. The concentrations of nutrients and organic pollutants greatly exceeded Cambodian discharge standards for wastewater. This causes environmental impacts, so treatment is needed before discharge. The faecal sludge characteristics and influencing factors identified here can serve as a baseline for sanitation stakeholders planning faecal sludge management systems in Phnom Penh and similar cities

Sustainability assessment of faecal sludge treatment technologies for resource recovery in Phnom Penh, Cambodia

Selection of appropriate sustainable treatment technologies involves satisfying user requirements, quality standards on treatment and products, and specific socio-technical constraints in the intended context. Using locally adapted multi-criteria assessment (MCA), this study investigated faecal sludge treatment technologies that enable resource recovery in Phnom Penh. A four-step structured approach was applied, involving i) identification of available options, ii) prerequisite screening, iii) MCA and iv) stakeholder discussions and ranking. Data were collected in a literature review, stakeholder interviews and an online survey. Lists of suitable primary (n = 7) and secondary (n = 13) treatment technologies were compiled based on the literature. Four secondary treatment technologies (solar drying, co-composting, vermicomposting, black soldier fly larvae (BSFL) composting) were retained after prerequisite screening and subjected to MCA. Co-composting was ranked highest in MCA, since it performed well in multiple aspects, especially for health criteria. However, when economic return on investment was prioritised and a lower treatment class was accepted, e.g. USEPA Class B biosolids, the highest ranking was achieved by vermicomposting or BSFL composting. If institutional criteria were included in the assessment, solar drying would likely be the highest-ranked option, since this simple technology requires less logistically complex stakeholder arrangements than co-composting. These results show that the ranking obtained for different sludge treatment options depends on criteria weighting and tradeoffs. Considering secondary treatment options is crucial during early planning for faecal sludge management in a city of low-and-middle income countries, as the primary treatment must yield appropriate feedstock quality for the secondary treatment step

Heavy metal contamination of faecal sludge for agricultural production in Phnom Penh, Cambodia

To achieve the universal target of ‘safely managed sanitation’ set out in UN Sustainable Development Goal 6, the world needs to increase its rate of progress, since e.g. Phnom Penh, the capital of Cambodia, currently has zero percent safely managed sanitation. One way to promote safer faecal sludge management is to shift to a more circular system with nutrient recycling, but this carries the risk of heavy metal accumulation in the environment. This study analysed the concentrations of heavy metals in raw faecal sludge from various sources and assessed the appropriateness of resource recovery and reuse in relation to the heavy metal and nutrient loads in faecal sludge. A total of 42 samples collected from sludge disposal sites in Phnom Penh during the dry and rainy seasons were analysed for heavy metals and physicochemical parameters. Mean measured concentrations of heavy metals in faecal sludge samples decreased in the order Zn > Cu > Pb > Cr > Ni > Hg > As > Cd in both seasons but were higher in the rainy season, probably due partly to inflow from stormwater drains and run-off from roads during storm events. All elements analysed were within the permissible limits for application to land according to EU standards and USEPA. However, Hg and Zn concentrations exceeded the tolerance limits for local organic fertiliser and Swedish limits for compost. Faecal sludge is thus not an appropriate fertiliser considering the risk of heavy metal accumulation in relation to phosphorus recovered. Options to avoid recirculating pollutants to the environment include upstream prevention of pollution, source separation of household wastewater fractions and use of biosolids as a soil conditioner together with other fertilisers or for soil production. Additional studies are needed on these options if sanitation stakeholders are to close the nutrient loop

Organic Matter, Solid and Pathogen Removals from Black Water in a Pilot-Scale Solar Septic Tank

Demonstrating the operational feasibility of a solar-powered septic tank as an alternative and sustainable sanitation option for communities was presented in this study. The efficiency and technical feasibility of a solar septic tank (SST) were tested and evaluated in pilot scale for treatment of black water from communal toilets. The system consisted of a modified septic tank equipped with a disinfection chamber inside the tank. Solar radiation was collected as a heat source for heating and disinfection. The system could achieve high removal efficiencies of total chemical oxygen demand (TCOD), 5-day biological oxygen demand (BOD5), total solid (TS), and total volatile solid (TVS) of 97%, 94%, 91% and 96%, respectively. The inactivation efficiencies of E. coli and total coliforms in the SST were about 2.2 log reduction. The increased temperature inside the septic tank could help to inactivate pathogens and reduce the environmental issues related to conventional fecal sludge management. In turn, this improved the water quality of groundwater and surface water and minimize health risks. Influence of operational conditions including organic/nutrient loading rate and ratio between TCOD and TKN in the black water on the performance of the SST were discussed

Solar Septic Tank: next generation sequencing reveals effluent microbial community composition as a useful index of system performance

Septic tanks are widely deployed for off-grid sewage management but are typified by poor treatment performance, discharge of polluting effluents and the requirement for frequent de-sludging. The Solar Septic Tank (SST) is a novel septic tank design that uses passive heat from the sun to raise in-tank temperatures and improves solids degradation, resulting in a cleaner effluent. Treatment has been shown to exceed conventional systems, however, the underlying biology driving treatment in the system is poorly understood. We used next generation sequencing (Illumina Miseq (San Diego, CA, USA), V4 region 16S DNA) to monitor the microbiology in the sludge and effluent of two mature systems, a conventional septic tank and an SST, during four months of routine operation in Bangkok, Thailand, and evaluated the ecology against a suite of operating and performance data collected during the same time period. Significant differences were observed between the microbiome of the sludge and effluent in each system and the dominant taxa in each appeared persistent over time. Furthermore, variation in the microbial community composition in the system effluents correlated with effluent water quality and treatment performance parameters, including the removal of chemical and biochemical oxygen demand and the concentration of fecal and total coliforms in the effluent. Thus, we propose that a wide-scale survey of the biology underlying decentralised biotechnologies for sewage treatment such as the SST could be conducted by sampling system effluent rather than sampling sludge. This is advantageous as accessing sludge during sampling is both hazardous and potentially disruptive to the anaerobic methanogenic consortia underlying treatment in the systems

Improving Environmental Sanitation, Health, and Well-Being: A Conceptual Framework for Integral Interventions

We introduce a conceptual framework for improving health and environmental sanitation in urban and peri-urban areas using an approach combining health, ecological, and socioeconomic and cultural assessments. The framework takes into account the three main components: i) health status, ii) physical environment, and iii) socioeconomic and cultural environment. Information on each of these three components can be obtained by using standard disciplinary methods and an innovative combination of these methods. In this way, analyses lead to extended characterization of health, ecological, and social risks while allowing the comprehensive identification of critical control points (CCPs) in relation to biomedical, epidemiological, ecological, and socioeconomic and cultural factors. The proposed concept complements the conventional CCP approach by including an actor perspective that considers vulnerability to risk and patterns of resilience. Interventions deriving from the comprehensive analysis consider biomedical, engineering, and social science perspectives, or a combination of them. By this way, the proposed framework jointly addresses health and environmental sanitation improvements, and recovery and reuse of natural resources. Moreover, interventions encompass not only technical solutions but also behavioral, social, and institutional changes which are derived from the identified resilience patterns. The interventions are assessed with regards to their potential to eliminate or reduce specific risk factors and vulnerability, enhance health status, and assure equity. The framework is conceptualized and validated for the context of urban and peri-urban settings in developing countries focusing on waste, such as excreta, wastewater, and solid waste, their influence on food quality, and their related pathogens, nutrients, and chemical pollutant

Roadmap for Innovators in the Process of Innovation for Development

This study aims to provide valuable insights into the process of innovation for development. We selected the “Reinvent the Toilet Challenge”, an initiative of the Gates Foundation, with the objective of creating sustainable sanitation solutions for the 2.5 billion people across the globe who lack access to safe and affordable sanitation. The Naturally Acceptable and Technologically Sustainable (NATS) team at the Asian Institute of Technology (AIT), Thailand was appointed by the Gates Foundation to serve as an innovative fecal sludge management (FSM) hub in Southeast Asia and collaborate with other researchers in the region, as well as with other teams from around the world to develop innovative FSM techniques that can help to solve the world sanitation problem. By gaining insights into how innovators interact with key stakeholders, we can understand the process of innovation for development and the role of innovation brokers in the innovation process, and then suggest a roadmap from the perspective of responsible research and innovation (RRI) to guide innovators, project leaders, industry partners, local government, and policy makers in the process of innovation for development