Stage 1

The modifications that we made in the first prototype in order to create better suction are listed here as our learnings from that phase of making the product.

Collection pipe size:

• With narrow pipe for collecting the dry leaves, one needs to spend a lot of time sweeping over the area, and then cleaning out the clogs. To overcome this disadvantage and to collect larger leaves using this prototype, the diameter of the collection pipe was increased from 3 cm to 7 cm.

The drawback of increasing the diameter of the pipe is the loss of airflow velocity which can decrease the suction efficiency. However, the increased fan size as well as reduced amount of collision neutralises the reduced efficiency.

In fact, the calculations show that the efficiency was increased which is practically also correct as we can collect bigger size of leaves with this prototype.

Video for working of Prototype -2

Eco-friendly Box for collection and processing of the dry leaves – An Idea

The original idea was to attach a jute bag to the suction mechanism for storage as well as composting of the dry leaves.

The benefits of using jute fabric in place of recyclable plastic or paper for making bags are as follows:

• Plastic bags (polybags) are manufactured from petroleum and they are non-biodegradable, and manufacturing paper bags requires a large quantity of wood. Whereas, jute bags are made from renewable natural fibres which are 100% biodegradable and recyclable, and hence an eco-friendly way.

• Moreover, the plastic or paper material might get contracted in the direction of the airflow. While the jute bags are made of a porous material. So, the direction of airflow will not cause any problem in this case.

• The composting of dry leaves can be done effectively in the jute bags as they have good insulating, low thermal conductivity, and moderate moisture regains properties. Also, the porous material helps in providing an oxygen-rich environment during aerobic composting.

• In addition to that, jute bags are also cost-effective, durable, and long-lasting.

We chose to use aerobic decomposition as opposed to anaerobic decomposition because anaerobic decomposition takes at least 6 months of time to compost dry leaves after they are collected and processed with required chemicals/components like water, soil, lime and fertilizer. On the other hand, aerobic decomposition takes only 4 to 6 weeks of time.

With a view of establishing an aerobic composting process in the closed environment, oxygen is needed to be provided inside the composting bin. As an aerobic composting process does not produce Methane gas (which is 26 times more potent than carbon dioxide) the adverse effects on the environment are already reduced. Plus, the small amount of carbon dioxide gas released due to composting can be used as a feedstock in industrial processes of making concrete, casting molds etc. Similarly, the small amount of ammonia released in the process can be deployed in the manufacturing process of textiles, pesticides, dyes etc.

Further, by providing a Nitrogen-rich environment and maintaining enough moisture inside the bin which is available in vegetable waste, fruits, and plant cuttings etc., the composting method can be made faster as Nitrogen acts as a catalyst for composting process.

This composting method was difficult for us to implement in this time period. For this project, we have used a simple cardboard box. Since we were working remotely, we were not able to implement the origami box that was separately made (shown in the image above).

However, given more time, we would have been able to work in the group together and implement the above-mentioned composting process.

As we could not achieve very efficient suction in prototype 1, we calculated the requirements and specifications of the motor to be used before building the second prototype:

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