# Sensor-Based Solid Waste Handling Systems: A Survey
## 4 Wireless Sensor Networks Based Solid Waste Management Systems
### Network Architecture  
A typical WSN architecture for solid waste handling system is shown in Figure 5. The architecture mainly consists of clusters, base station, and central monitoring station. Each cluster includes several trash bins equipped with sensor nodes, and all these sensor nodes are connected to a coordinator node. The coordinator nodes of various clusters are connected to the base station, which will act as WSN's processing unit. Furthermore, the base station will share data to the internet for establishing remote monitoring facilities. A comparison of various wireless communication technologies that enabled WSN is shown in Table 2. \begin{table}
\begin{tabular}{l c c c c c} \hline
**Ref.** & **Bin Deployment** & **Sensors** & **Camera** & **GPS** & **GIS** & **Routing** \\ \hline
[27] & exterior & none & Yes & Yes & Yes & undefined \\
[28] & exterior & none & Yes & Yes & Yes & undefined \\
[29] & not specified & infrared sensor & No & Yes & No & undefined \\
[30] & exterior & ultrasonic sensor, pressure sensor, & Yes & Yes & Undefined \\
[31] & exterior & load cell sensor & No & No & Undefined \\
[32] & interior/exterior & photoelectric, image sensor & No & Yes & No & defined \\
[33] & exterior & digital weight scale & No & No & No & undefined \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of RFID-enabled Trash Bin Level Monitoring Systems. The advancements in wireless technologies face-lifted solid waste management systems that were bound to the limitations of establishing real-time monitoring and wide-range deployments. This section presents a comparative analysis of various WSN-enabled trash bin level monitoring systems. Table 3 shows the summary of WSN-based systems concerning communication technologies. A WSN architecture for solid waste management based on Zigbee networking protocol is presented in [34]. The architecture comprises three modules: data collecting, data processing, and notification. The end nodes mounted on the trash bins measure the unfilled level and update the server through a Zigbee coordinator. Moreover, to save time and money, notifications are sent to the garbage pickup unit using the Telegram messaging service. An intelligent trash bin monitoring system with Zigbee network architecture is presented in [35]. The smart nodes enabled with the Zigbee networking protocol transmit the sensed data (filled level of trash bin) to the Zigbee coordinator. The Zigbee coordinator node receives data from all smart nodes and send data to the cloud server when sensed data crosses the threshold level. The cloud server will assess the degree of fullness of trash bins for optimal route planning for waste collection. In addition, the sensor nodes are designed for harvesting energy by using solar energy to extend the lifetime of the nodes. However, the system fails to provide a real-time visualization of the trash bin's filled level. A network architecture employed with ArgosD sensor nodes is presented in [36]. The nodes are enabled with CC2420 RF transceivers, MSP430F1611 microprocessor, and a sensor. The graphical user interface displays the bin level but not the organizational level. In addition, as compared to conventional approaches, the current consumption and wake  
Figure 5: A typical WSN architecture for solid waste handling systems. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Wireless Technology** & **Wireless Range** & **Power Consumption** & **Operating Frequency** & **Data Rate** \\ \hline Zigbee & 10–100 m & Low & 2.4 GHz & 20–250 kbps \\ Wi-Fi & 100 m & Medium & 2.4 GHz, 5 GHz & 10–100 Mbps \\ Bluetooth LE & \textgreater{}100 m & Low & 2.4 GHz & 125 kbps-2 Mbps \\ Z-Wave & 15–150 m & Low & sub-GHz & 9.6–40 kbps \\ IEEE 802.15.4 & 10–20 m & Low & 2.4 GHz & 250 kbps \\ SimplicTi & 50 m & Low & 2.4 GHz & 250 kbps \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of popular WSN-enabled wireless technologies.