Research and Development

Walden’s ongoing research and development efforts focus on the investigation and improvement of a diverse suite of environmental concerns, including surface water pollution, wastewater treatment, energy recovery as well as renewable energy applications from the standpoint of mitigating greenhouse gas emissions. Walden’s scientists and engineers evaluate challenges to be addressed, conduct detailed investigations, and develop unique and sustainable measures that contribute towards the improvement of environmental quality.

Walden’s current Research and Development Efforts include the following areas:

  • Illicit Discharge Detection and Investigation; Surface Water Pollution Management
  • Renewable Energy Application and Associated Environmental Impact Assessment
  • Wastewater Treatment Improvements
  • Energy Recovery/Optimization of Energy Consumption
  • Leak Detection for Drinking Water Distribution
  • Construction Site Remote Monitoring  


MS4 Illicit Discharge Detection Investigation using Thermal Imaging UAVs (2020)

Walden is working to improve surface water quality by using thermal imaging to efficiently identify sources of pollution, which is a key criteria of the Nassau County Soil and Water Conservation District’s 2020 Project Request. Efficiently identifying heat differentials in the soil using aerial thermal imaging technology can pinpoint illicit discharges, failing onsite wastewater treatment systems and other pollution sources, which can then be inspected and abated by local municipalities. Once the initial site assessment and thermal imaging analysis is completed, Walden will conduct field follow-up visits to determine possible sources of pollution. Walden will identify if the heat differentials detected in any of the locations are due to an illicit discharge, or are other sources of heat. Walden will generate reports on any detected discharges or other relevant environmental conditions determined by the field work, analysis and field follow-up.

Mitigation of Wildlife Impacts and Habitat Loss While Advancing Development of Non-Residential PV Systems –Town of New Paltz’s Landfill and Adjacent Wooded Areas Solar Facility Project (2020)

Walden is assisting with the development of a non-residential 5.0 MW solar photovoltaic (PC) project at the 189-acre Town of New Paltz (Town) facility, that consists of a capped landfill, recycling center, waste transfer station, Town offices, recreational facilities and vacant, unimproved, grassland and woodland areas. As part of the ongoing efforts in the implementation of this project, Walden is working on the development of holistic, wildlife-friendly PV solar systems to ensure that implementation of PV systems do not result in loss of habitat for wildlife. Walden is conducting a field study of the Town Solar PV Site and nearby areas as an initial step to assess the baseline wildlife communities living on the existing grassland (capped landfill) and woodland habitats using birds and insects as indicator species. The initial findings will be used to guide Walden’s desktop study of solar design elements and approaches intended to reduce impact on wildlife. The most compatible and cost effective design will be incorporated into the project. The timing, cost, constructability, permitting and other design process aspects will be documented during this phase. Once the operation of the PV system commences, Walden will return to the site areas to assess any changes in the bird and insect communities.

Renewable Energy Production and Storage Review and Feasibility Study at Wastewater Treatment Plant (2020)

Walden investigated the feasibility of utilizing solar energy technology at the New Paltz Wastewater Treatment Plant (WWTP). Walden assisted in the evaluation of the electric consumption of the process equipment of the WWTP, in order to determine the extent to which solar energy can be utilized for the electric requirements of the WTTP operations. Walden also assisted in the determination of the most feasible location for the installation of Solar PV panels, in terms of installation costs, extent of required demolition for installation of panels and extent of flood protection prevalent in the location.

Optimization of UV-Advanced Oxidation Processes in Wastewater Treatment (2019)

UV-advanced oxidation processes (UV-AOPs) use a combination of UV light and oxidizing chemical compounds in wastewater treatment for the removal of synthetic organic contaminants, such as pharmaceuticals, flame retardants and personal care products. The presence of background organic matter in wastewater reduces the efficiency of the UV-AOPs, which results in excess consumption of UV energy as well as chemical compounds. Investigations were conducted to provide clarity on the mechanisms through which the background organic matter interact with UV-AOPs, so that the performance efficiency of UV-AOPs can be improved in the future. This will contribute towards the optimization of UV energy as well as chemical compounds ‘consumption and thus achieve cost savings in wastewater treatment.

Thermal Imaging with Unmanned Aircraft (Drone) to Search for Leaking Underground Water Piping (2019)

Walden used thermal imagery with unmanned aircraft to detect leaks in underground piping in Village of New Paltz, in order to curb the loss of drinking water from pipes. Leak detection was possible by observation of infra-red (IR) radiation from warmer or colder water, relative to the environment. Thermal imagery obtained at dawn was used for the detection of leaks, as the IR sensor’s ability to distinguish between heat sources is maximized when solar radiation is at a minimum. Leaks in curb water valves were detected with this approach.

Remote Real-time Environmental Monitoring at Construction Sites

Walden has worked on the implementation of IoT pilot studies for environmental monitoring, sensor array installation and data analysis. Real-time environmental monitoring at construction sites can be achieved by utilizing IoT sensor networks, cloud storage and user interface dashboard. Walden helped Second Avenue Subway Project optimize their community complaint response times. Community response times depend upon the amount of time it takes to receive a complaint ticket, locate the nearest monitoring equipment, download the relevant data and produce a report to mitigate the situation. Walden optimized the community response time by facilitating the installation of sensor arrays in close formation which record data real-time around a jobsite.  Real-time data can be presented to the client or construction manager on a user interface or dashboard via a cloud. This enables immediate response to complaints. Forecasts and predictions to job site conditions can be also be accomplished using real-time monitoring, which helps in preventing potential issues from taking place.