vessel’s sonar system emits acoustic signals downward.
Effluent ponds are a crucial component in waste management for industries like petrochemical, oil and gas refineries, mining, pulp and paper, agriculture, hydroelectric power generation and wastewater treatment. However, they often go unnoticed in discussions about technological innovation.
Yet, beneath their seemingly placid surfaces lies a complex world of sediment and sludge accumulation that demands our attention. Traditional methods of monitoring these sediments are labour-intensive, risky, and sometimes environmentally disruptive. Recently though, acoustic sonar sediment remote surveying, a cutting-edge solution, is transforming how we understand and manage these hidden depths.
Over time, effluent ponds collect sediments composed of organic matter, minerals, and other particulates. This gradual buildup can significantly reduce capacity, affect its efficiency in processing waste, and even pose environmental risks if not properly managed.
Conventional surveying methods often involve manual probing or draining the pond, which are not only hazardous but also interrupt the pond’s operation. Underwater acoustic sonar offers a non-invasive alternative. By emitting sound pulses into the water and analyzing the echoes that bounce back from the pond’s bottom and sediment layers, sonar systems create detailed maps of underwater topography.
Coupling sonar technology with remote survey vessels amplifies the benefits. These unmanned, GPS-guided boats can autonomously navigate across the pond’s surface, collecting thousands of data points efficiently and safely. Equipped with high-resolution sonar equipment, they eliminate the need for human operators to be physically present on the water, reducing safety risks and operational disruptions. Here is how it works.
Deployment – The remote survey vessel is released onto the ponds and open top clarifiers often by a crane, since vehicle access close to the water edge may be very restrictive. Once the vessel is on the pond’s surface the navigation is either guided by pre-programmed navigation paths or controlled remotely.
Data collection – As it glides over the water, the remote vessel’s sonar system emits acoustic signals downward. These signals penetrate the water column, reflecting off different layers, most notably the sediment-water interface. Remote survey vessel GPS tracking in real-time on the pond is seamlessly integrated with the sonar data, that is collected and stored in a powerful computer system. This sonar computer system is located on the survey vessel in a water-proof housing secured to the hull.
Utilizing radio frequency, the sonar and GPS data can be sent from the survey vessel’s onboard computer system to a computer system onshore, for the sonar specialist to review. To ensure adequate survey coverage, especially on large ponds, survey vessel tracking, which incorporates location and speed, is scrutinized closely.
Data interpretation – The time it takes for the acoustic signals to return is meticulously measured. Differences in return times and signal strengths help determine the depth and density of sediment layers. Multiple transducers of different frequencies are utilized to create a more effective and accurate sonar system.
The low-frequency transmitter (50 kHz and below) emits sound waves that can penetrate deeper into the water and sediment capturing the pond’s sub-bottom or its “liner” i.e., clay, riprap, concrete contour profile. Medium-frequency transmitters (83 kHz to 160 kHz) offer a balance between depth penetration and image resolution. They can cover a wider area and provide more detailed information than low-frequency transducers.
High-frequencies (200 kHz and above) emit sound waves with shorter wave lengths, resulting in more detailed pond sediment mapping of the bathymetry or the top of the sediment layer.
Utilizing a specific configuration of transducers specifically engineered for shallow depth effluent ponds and open top clarifiers helps to validate bathymetric and sub-bottom sediment depths and ultimately the total sediment volumes when further data processing is completed.
Mapping and analysis – Collected data is translated into vivid, three-dimensional maps and cross-sectional profiles of the pond’s sediment deposits. Advanced software allows for real-time visualization and analysis.
UNDERSTANDING THE BENEFITS
This approach removes personnel from potentially hazardous environments, minimizing the risk of accidents. Surveys can be conducted without halting pond operations, saving time and resources, while precise measurements surpass the capabilities of manual methods. Finally, non-invasive surveying protects aquatic life and maintains the integrity of the pond’s ecosystem.
While effluent ponds are a prime beneficiary, this technology extends to various aquatic settings, such as monitoring sediment for stability assessments in mining tailings ponds, guiding dredging activities by pinpointing sediment levels and ensuring capacity and integrity of reservoirs.
A SIGNIFICANT LEAP FORWARD
Underwater acoustic sonar sediment remote surveying represents a significant leap forward in how we manage and understand aquatic sedimentation. By embracing this technology, industries can make informed decisions that promote operational efficiency, regulatory compliance, and environmental protection. It is a great example of how innovation can turn challenges into opportunities.