Stormwater Management Systems
Wahaso Stormwater Harvesting Systems
Depending on the site, stormwater detention or stormwater collection areas can be quite large and often contain contaminants such as silt, hydrocarbons and fertilizers in their stormwater harvesting system. Increasingly, communities are requiring developers to manage their stormwater runoff in order to reduce the load on the local storm system with a stormwater management system.
Wahaso’s stormwater system not only accommodates large quantities of stormwater but provides more robust treatment designed to handle difficult contaminants. The result is a system that provides a safe, treated supply of water that can be used for a variety of non-potable applications.
More and more communities are requiring developers to manage the run-off from their impermeable rooftops, hardscapes and parking areas to reduce the impact of the run-off on municipal treatment systems. This requires builders to install storage tanks that slowly release collected stormwater into surrounding waterways to protect the municipal treatment facilities from high stormwater flows.
This storage can require an investment of hundreds of thousands – or millions of dollars to filter the stormwater, remove hydrocarbons and then detain the treated water until the storm event has ended. Normally these detention systems represent a “sunk cost” from which the property owner will receive no direct benefit.
Turning a Liability into an Asset
Economics and Return on Investment
Stormwater Detention System Design
Wahaso recommends the Nutrient Separating Baffle Box (NSBB), which utilizes screening and hydrodynamic separation to capture the pollutants common in stormwater. The NSBB stores debris in a dry state, minimizing bacterial growth and nutrient leaching in the water.
The proprietary treatment train of Wahaso’s stormwater system is IAMPO 324 certified and filters the harvested water down to 0.02 microns, removing suspended solids as well as bacteria and viruses. Filtered water is sanitized using Ultraviolet (UV) and if required, chlorine, and is then sent to the end use or stored in a processed water holding tank to await re-pressurization.
The treated water is safe and suitable for non-potable applications such as toilet flushing, irrigation and cooling tower make-up.
- Turn a Liability into an Asset. Stormwater management often requires a detention system to hold the water for a period of time and release it slowly to the municipal storm system. Instead of releasing the water, why not retain it for reuse? The Wahaso stormwater harvesting system provides a way to collect and treat that water, providing a more sustainable and cost effective solution to stormwater management.
- Scalable. The Wahaso stormwater system can be Scaled to treat from 2,000 to 200,000 gallons per day or more.
- Low Maintenance. The system has been designed to run reliably for long intervals, with minimal maintenance required.
- Robust Controls. Wahaso’s proprietary control system is custom programmed to monitor and track all system activity.
- Integrated System Design. Wahaso’s stormwater processing skids are pre-assembled and integrated into comprehensive system designs that include all pumps, storage, filtration, sanitation and controls.
For more information on our stormwater harvesting systems, download the information sheets.
The OptiRTC system
For parking stormwater and high-capacity flows from large rooftops, Wahaso likes the Nutrient Separating Baffle Box system developed by Suntree Technologies. These systems utilize screening and hydrodynamic separation to capture pollutants in stormwater.
Patented Screening System
We like the Atlantis D-Raintank system because of its design flexibility, low cost compared to other options and its interactivity as a storage system. Stormwater stored in the Atlantis D-Raintank system can be retained for reuse by adding an impermeable liner to the excavation. Water quality is maintained in the cool and dark cistern and improved through capillary action and microbe interaction in the surrounding compacted material. Sand is compacted around the sides and top of the storage tank between the permeable geotextile liner around the tank and the impermeable containment liner. Surface water can enter the tank directly by filtering through the compacted material above the tank, and water in the tank is able to interact with the compacted material on the sides. This action helps keep the water in the tank oxygenated and microbes in the soil layer act on organic material in the cistern to further purify the stored water. For information on additional storage methods, visit our Storage Options page.
After detained stormwater has been filtered, we then sanitize the water using ultra violet light—a chemical free, low maintenance approach to sanitation. This process kills any harmful bacteria or pathogens in order to meet health codes and ensure that the water is safe for spray irrigation systems. Submersible pumps are stainless steel with variable frequency drives and are used for pressurization. The sub-surface placement of the system reduces system footprint and allows complete flexibility in the location of the processing skid.
Rainwater Harvesting Systems
Pre-treated stormwater can also be used to source a rainwater harvesting system for application in toilet flushing, cooling tower make-up and more. Water is sanitized using UV light as described above, or chlorination, a common approach that uses sodium hypochlorite to produce a highly concentrated chlorine liquid. This chemical is similar to that used in a municipal water treatment systems but is in a form that is safer and easier for building maintenance staff to handle. Water must then be pressurized at a flow rate that is determined by its intended application.
Wahaso Stormwater Management Systems FAQ’s
Wahaso is happy to talk with you about how we might help you convert your stormwater detention to retention and reuse through harvesting. Please contact us.
1. What is stormwater harvesting used for?
Stormwater harvesting involves collecting rainwater at grade to meet various water demands, including irrigation, washing, drinking, and cooling. This includes pervious and impervious areas like walkways, lawns, decks, parking lots grade. The four key components of stormwater harvesting are:
- Storage/cistern – This may be above ground, below ground, concrete vault, modular, corrugated, HDPE or fiberglass
- Filtration – This includes pre-filtration prior to water going in the cistern and the type of filtration depends on the type of water and where the system is located
- Sanitation – This can be either UV light, chlorine, ozone or cupridyne
- Controls – Measures tank levels, flow rates, water savings and pump and system statuses.
2. What is the difference between rainwater harvesting and stormwater management?
3. Why is stormwater harvesting important?
4. How do stormwater harvesting and reuse work?
Stormwater harvesting and reuse is an intricate system involving the collection, treatment, storage, and use of stormwater runoff. The four main stages of this system are:
- Collecting the stormwater from a source, such as a drain
- Temporarily holding the water in a below- or above-ground storage
- Treating the water to reduce pathogens and contaminants
- Distributing the treated water for non-potable reuse
5. Can stormwater be used for irrigation?
6. How does stormwater management help control flooding?
7. Are surface water and stormwater the same?
8. What is the only liquid that should enter the stormwater system?
9. How can stormwater be reused?
There are numerous ways to reuse stormwater. These include indoor and outdoor applications.
- Toilet Flushing
- Washing machines
- Cooling Tower Make-Up
- Fire suppression
- Process and boiler water
- Fire fighting
- Sanitary sewer flushing
- Street cleaning and dust control
- Vehicle and building washing
- Water features
10. What contaminants can be found in stormwater?
Our mission at Wahaso is to help municipalities and commercial property owners reduce the impact of their buildings on the environment through innovative and sustainable water practices.