Welcome to this module on applying the waste flow diagram. In the introductory module, we explained the basics of the waste flow diagram tool. A rapid and observation based assessment to quantify plastic leakages from municipal solid waste management system into the environment. After watching this module, you will be able to quantify plastic leakages as well as to determine their final fates. For that, we will see how to apply the tool in order to evaluate a disposal site. These are the three sets of ingredients you need for such assessment. The linkage decision tree and description tables to estimate the amount, the fate decision tree and description tables to determine the fate and to conduct observations and compile a good understanding of the situation at the disposal site. So let's start quantifying the literature's. Here we see the leakage decision tree for disposal sites. It combines six leakage influencers. For every influencer, we can see the different leakage potential levels and their corresponding leakage factors. For the case of disposal sites, you will notice that there are two separate plastic leakage types. One caused by water, and the other one caused by wind. Their total leakage is the sum of both as shown in the formula below. You will also notice that the water driven leakage only has one leakage influencer, whereas the windblown leakage has five. The user of this tool should assess through observations the level of potential leakage of each of these leakage influencers. Let's have a look at them one by one. The first one environmental hazards, looks at the frequency and impact of flooding events or landslides, which can carry disposed plastics from the site. This influencer has five possible leakage potential levels, which are described in this table. Let's see now some real examples. This disposal site from Sierra Leone is crossed by the river which goes directly into the sea. It is clear that it washes out all the waste that ends up in its basin. However, compared to the total site of the landfill, we can say, that the site, is located in an area where regular flooding or landslides, impact small parts of the site. From the descriptions given in the table, it would fit best, with the medium level. In this second example from Senegal, however, we see that the disposal site is located in an area prone to occasional flooding or landslides impacting large parts of the site. For this case, therefore, we would choose the high level. Let's move now to the wind related five leakage influencers. These are combined to calculate the total windblown litter. Let's start with exposure to weather. This influencer assesses the frequency of strong winds on the site. This information can be obtained by interviewing the site managers or checking weather records. This influencer has three leakage potential levels as shown in the table, high, medium, and low. If a disposal site is regularly exposed to heavy and persistent winds like these ones, the user should opt for the high level. The third influencer on the list is waste handling at the point of discharge. This influencer has four potential levels and consists of several aspects. In this site from Sierra Leone, where there is no designated district's own waste pickers are active on all the site. There is no compaction or management of waste and waste is piled above ground with full exposure to wind, rain and surface runoff. The leakage potential will be very high. In contrast in these older sites from Morocco, where waste is discharged in designated zones, waste pickers are not allowed on site and there is compaction or management of waste, the leakage potential is low. The next leakage influencer is coverage. This influencer looks at the frequency and effectiveness of coverage of the disposed waste. It has four leakage potential levels. If waste is typically covered daily, like in this example from Brazil, then the leakage potential is low. However, if waste is not covered or covered less than once per month, like in this site from Bolivia, then the leakage potential is very high. Then we assess presence of burning. In spite of being a very undesirable and hazardous occurence, burning can also act as a trap and reduce the amounts of plastics that are prone to be wind-blown by combusting them. It also has four leakage potential levels. Disposal sites like this one from Senegal, where waste burning is widespread and prevalent will have a low leakage potential. Finally, the existence and effectiveness of fencing on site should be observed. These influence are also consists of four potential levels. If a fence surrounds the entire perimeter and it is maintained like in this site from Brazil, it can capture a big portion of the flying plastics. >> [INAUDIBLE] Now let's work through an example together. Let's assume a fictitious disposal site, located in the city of around 3 million people. South receives 450 tons of municipal solid waste per day 10% of waste is plastic. Therefore 45 tonnes of plastic waste per day in total. Assume as well the influences relevant to the disposal site were assessed at the level shown here. Notice our site has no water driven leakage. The waste flow diagram then combines all corresponding leakage factors following the formula given under the decision tree. Are the level selected, the waste flow diagram calculator will be 23 kilograms of plastic leakages per day, namely plastic escaping from the disposal site into the surrounding environment. This represent around 0.05% of the incoming 45 tonnes of plastic waste deposited per day. Once we have calculated the leakage amount, we can proceed to determine whether this leaked waste will end up. I handover to Dr. Josh Cottom who will guide us through the allocation of these fates. >> Thank you. Leak plastic is assumed to end up in one of the four following fates. Retained on land, burnt, cleaned from storm drains, or retained in water systems. The waste flow diagram, classifies the leakage flows originating from the stages of solid management systems, according to two criteria. Firstly, they assess the area over which the leakage occurred. If this was from one location, is known as a point source leakage, whereas if it occurred in many different locations is known as a diffuse leakage. Secondly, it assesses whether the leakage was a voluntary act, such as dumping by residents, or if it was an involuntary act, such as being blown away by wind. Let's consider a disposal site again. Here the leakage occurs from the set location and is leaked through either wind or rain. It is therefore assigned a point source involuntary leakage type. In a similar manner to the waste flow diagram categorizes each of the leakages are shown in this table. Each category has its own specific fate decision tree to determine where the plastic leakage ends up. For example, here is the point source involuntary fate decision tree that applies to our disposal site. You will notice we have three fates, land, drains, and water bodies. For involuntary leakages like this one, burning is not considered as a fate. This is because the plastic is being leaked by natural forces such as wind or rain or not by humans. Therefore, this leak plastic waste cannot be burnt. You can see each of the fates in our decision tree has several options with accompanying fate factors from none to very high. Description tables in the user manual outlines the different requirements for choosing each fate potential. Here we see the descriptions for the fate land. Similar to how we did the leakage influences, the user should conduct local ground based observations to decide which descriptions in the tables best matches with what they're observing in each location. As plastic is carried away by water bodies, and therefore may not be observed, we know the proximity of water bodies within the area instead. The chosen fate potentials are then combined in the equations at the bottom of the decision tree to determine the distribution of the fates. Great, now let's look at an example together. Considered we did observations around our fictitious dump site. For our previous leakage assessment, we determined 23 kilograms a day is expected to leak from the dump site. We then noticed an observations, there were some small areas with large amounts of waste trapped in the vegetation and retained on land around the site. We also observed only minimal cleaning of the storm drains occurred in the area and a number of water systems were in close proximity. Matching these observations with the description tables, we therefore decided on the following fate potentials. Using the equations at the bottom of the decision tree, the waste flow diagram calculates of the 23 kilograms a day leaked 62% remains on land. Another 15% goes into storm drains and is later removed by cleaning and the remaining 23% goes to water systems. So we've seen how to calculate plastic leakage and its fate from a disposal site. Similar approach can be followed with all the stages of the solid waste management system in order to get the total lead amount into the environment. The results are then presented in a plastic flow diagram as the one shown here >> In this module, we saw how to apply the waste flow diagram tool in the example of a disposal site. We saw how to calculate the amount of plastic leaked into the environment as well as how to determine where in the environment it ends up. So go and try it out yourself in your city and tell us how it went. Follow the instructions given in the user manual. For more in depth knowledge on the topic, we recommend the following key literature. For a more in depth assessment, other tools are available, such as the International Solid Waste Association Plastic Pollution Calculator. Thank you for watching.
