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

A concept for planning and management of on-site and centralised municipal wastewater treatment systems, a case study in Bangkok, Thailand. I: Pollutant discharge indicators and pollutant removal efficiency functions

The concept of pollution load indicators for planning and management of the mixture conditions of centralised and on-site wastewater treatment systems has not been discussed in detail so far. In this paper, pollutant discharge (load) indicators and pollutant removal efficiencies were quantitatively analysed to develop a part of a strategy for planning and management of municipal wastewater treatment systems (WWTSs) under the mixture conditions in Bangkok, Thailand, as a case study. Pollutant discharge indicators of on-site WWTSs were estimated based on the relevant literature. Three kinds of pollutant removal efficiency function at centralised wastewater treatment plants (CWWTPs) were empirically developed for biological oxygen demand, chemical oxygen demand, total nitrogen, total phosphorus, total coliforms and faecal coliforms based on the existing CWWTP management data. These results will be integrated into the scenario-based analysis in the second paper in the series. The results will be base datasets, and the concept and estimation methods can be applied for wastewater treatment planning and management in other areas

A concept for planning and management of on-site and centralised municipal wastewater treatment systems, a case study in Bangkok, Thailand. II: Scenario-based pollutant load analysis

Scenario-based pollutant load analysis was conducted to develop a part of a concept for planning and management of wastewater treatment systems (WWTSs) under the mixture conditions of centralised and on-site WWTSs. Pollutant discharge indicators and pollutant removal efficiency functions were applied from another paper in the series, which were developed based on the existing conditions in urban and peri-urban areas of Bangkok, Thailand. Two scenarios were developed to describe development directions of the mixture conditions. Scenario 1 involves keeping the on-site wastewater treatment plants (WWTPs) within the areas of centralised WWTSs. Scenario 2 is dividing the centralised and on-site WWTS areas. Comparison of the smallest values of total pollutant discharge per capita (PDC) between Scenarios 1 and 2 showed that the smallest PDC in Scenario 1 was smaller than that in Scenario 2 for biological oxygen demand, chemical oxygen demand and total phosphorus whereas the smallest PDC in Scenario 2 was smaller than that in Scenario 1 for total nitrogen, total coliforms and faecal coliforms. The results suggest that the mixture conditions could be a possible reason for smaller pollutant concentrations at centralised WWTPs. Quantitative scenario-based estimation of PDC is useful and a prerequisite in planning and management of WWTSs