Assessment of waste collection systems and separate collection alternatives in Vietnam

The volume of solid waste has been increasing in recent years with the rapid growth of economics and population in many countries all over the world.Especially, it becomes a critical issue for developing countries in solid waste management due to lack of careful management of system including collection and treatment.As one of the forward thinking municipalities in Vietnam, Da Nang city has been trying to improve the operation efficiency of waste collection and transport, and has introduced various collection systems in some parts of the city; e.g., tricycle collection, dustbin collection, and truck collection.However, the plan for waste collection and transport has been empirically designed, and the operation efficiency has not been well considered even in this motivated city.Increase in collection efficiency and introduction of separate collection are the key issues with high priority in Vietnamese MSW management under the rapid increase of MSW generation.To achieve the challenging national targets, municipalities in Vietnam need to consider the operation and factors to improve the efficiency, and design a rational plan for waste collection and transport with the support of scientific information.Meanwhile, in City A, Japan, waste system is currently being implemented with separate collection with low frequency.To reduce resource and proper disposal, the sorting division of garbage was changed drastically in FY 1999, and four types (combustible waste, incombustible waste, bulky waste, used batteries).It was applied in the whole area.In addition, the municipality started collecting PET bottles from October 2009 and pick up of used small electronic equipment from January 2005.Also, from April 2008, a digital tachograph was installed on all collection and transport vehicles in the same area, and the work time by classification such as waste loading, running, moving etc are sequentially recorded.These data are being used for operation management / planning etc.Therefore, in order to solve the current waste problems, primarily it is a need to create a waste arising database whether in Vietnam or Japan to provide credible information for waste managers and planners into local and region term.In the study in Da Nang city, the authors focused on the major alternatives to waste collection and transport practices used in Da Nang city.GPS devices and a GIS software were used to survey and analyse the detailed tracking data on 3 current practices; "Door-to-door collection by tricycle and transport by truck", "Door-to-door collection and transport by truck", and "Fixed time dustbin collection and transport by truck".The operation efficiency indicators, such as unit operation time, person-hours/t and operation velocity were calculated using a detailed operation category: moving forward and backward, waste collection waste, unloading and other activities.Using multi-regression analysis, the authors estimated the unit loading time and the unit waste amount for 4 types of containers, 240-L dustbin, 280-L dustbin, 660-L dustbin and Handcart.To provide the scientific base for rational planning of waste collection and transport, the authors aimed to estimate and compare the operation efficiencies of major alternatives in Da Nang city, and clarify the impacts of policy factors such as the truck capacity and the collection frequency.In addition, the authors also tried to estimate the operation efficiency of separate collection of biodegradable waste as the most likely alternative in the near future.By using the data for the 3 current practices on operation time, operation distance, and collected amount, key statistics for each parameter were calculated.And the operation efficiency indicators such as unit operation time, person-hours/t and operation velocity were calculated by the detail operation category: Moving forward and backward, waste collection, waste unloading and other activities.By using multi-regression analysis, the authors estimated the unit loading time and the unit waste amount for 4 types of containers, 240-L dustbin, 280-L dustbin, 660-L dustbin and Handcart.Models of operation parameter (moving velocity, transport velocity) were also constructed in related to area factors and characteristics as population density, road category, moving distance.Moreover, the author suggested the current problems of waste collection system in Da Nang are still remained: the mixed waste collection is implemented daily, and all the waste stream come to landfill site while landfill capacity is limited.A large quantity of recyclable waste was not recovery due to this combine collection system, and this might burden on the landfill capacity and demonstrate the inefficiency in material recovery.Besides, waste separation collection as well as impact factors have not been strongly considered in designing the system.Therefore, waste separation collection could be examined in term of collection efficiency and financial aspects in Da Nang city to solve these problems, however to reduce the cost, the impact factors by system and area characteristic should be also approached and researched.Regarding on waste system operation analysis in a Japanese city, in terms of basic unit of collecting work time by item, the total working time per ton, total distance of collecting / transporting per 1t, collected weight per station, significant difference was found among items.According to the waste type, the total working time per 1t, which is a representative index of collection efficiency, the combustible waste was the smallest at 1.21 hours/t, equivalent to 2.42 person-hours/ton with 2 workers/truck.And the PET bottle was the longest at 10.41 hours/t.Based on the population data of the target area and the amount of collected waste, the basic unit of collected amount was determined by first 4 days in the week and 3 days in the latter half of the week.Waste amount was divided by the number of days to calculate the basic unit.Monday was 589.9 g / person / day and 608.9 g / person / day on Thursday, 551.3 g / person / day on Tuesday and 550.3 g / person / day on Friday were nearly equivalent values.The basic unit of recycled materials was 2.6 ~ 21.0 g, which was considerably smaller than 575.4 g of combustible waste.This separation waste type collection system could be a feasible solution for developing countries in term of operation efficiency and recyclable material recovery as well as aesthetic of the city by informal sector reduction.Regarding on scenario analysis, the results were indicated that, in Hoa Cuong Nam ward in Hai Chau district, the operation efficiency of "Door-to-door collection" was 4.37 person-hours/t, which was lowest among the current 3 practices, and that of "Door-to-door collection and transport by truck" was 3.65 person-hours/t."Fixed time dustbin collection and transport by truck" achieved the highest efficiency of 2.10 person-hours, which was less than half of "Door-to-door collection and transport by truck".The operation efficiency would be affected by truck capacity and collection frequency.By sensitivity analysis on "Fixed time dustbin collection and transport by truck", the best efficiency was 0.64 personhours/t achieved at "Once per week and 9t", and the worst efficiency was 2.52 person-hours/t at "7 times per week and 4.5t".The variation range of operation efficiency by collection frequency from "Once per week" to "7 times per week" was 1.46 person-hours/t, while the ranges by truck capacity from "4.5t" to "9t" were from 0.42 person-hours/t to 0.63 person-hours/t.To improve the collection efficiency, the expected impact of collection frequency was larger than that of truck capacity, even in the farthest collection area.The operation efficiency of separate collection of bio-waste by plastic bag was 3.40 person-hours/t.It was better than door-to-door collection scenarios, which means it would be a feasible alternative that can replace door-to-door collection practices.As sensitivity analysis of separate collection of bio-waste by plastic bags, the operation efficiencies by various combinations of collection frequencies of biowaste and other waste were assessed.The best efficiency was 0.82 personhours/t achieved at "Once per week for 2 waste categories", and the worst efficiency was 3.40 person-hours/t at "7 times per week for 2 waste categories".The authors found some conditions with better efficiencies than "Fixed time dustbin collection and transport by truck", e.g., "7 times per week for bio-waste and once per week for Other waste".The variation ranges of operation efficiency by separation rate were 2.20 person-hours/t, which was the largest range among those of influence factors considered in the sensitivity analysis.To introduce separate collection of bio-waste, it is indispensable to consider proper collection frequency.Separation rate is a critical factor on operation efficiency, and should be carefully considered for planning separate collection.Moreover, to obtain the acceptance and be further utilized in areas, waste collection system should also be proven their efficiency in term of financial performance.Therefore, the author also estimated efficiency of practices in cost/t.Interestingly; waste separate collection often has higher cost than commingle collection, however with lower frequency it would reduce expenditure significantly.By propose one scenario for separate waste type collection, the results showed this system can achieved well efficiency not only in operation but also financial aspects compare to informal sector.Results of this dissertation suggested the methodology of waste collection survey, and identify the efficiency of each collection system clearly.Based on that, the operation efficiency of collection system among alternative countries can be compared to clarify the feasible improvement in the system.And the impact of other factors to waste collection system which were assessed by sensitivity an