As regulations on cannabis cultivation facilities come into shape, municipalities will continue to further investigate power, water, and nutrient use in the industry. Working with experienced engineers and consultants, sourcing the optimal equipment, and scrutinizing all essential inputs will ensure the most efficient cannabis production facility as possible. Many operation managers and municipalities have not yet considered the regulations controlling water usage and wastewater discharge. These regulations would impact cannabis producers dramatically and may even put some out of business due to higher operating costs and competition.
As the industry evolves, certain water regulations put in place could jeopardize an existing operation’s legality. As drought-stricken states like California, Nevada, and Arizona develop regulations on cannabis cultivation operations, water volume usage and discharge will be something municipalities in those states will closely consider, if they haven’t already.
The two main water regulations on cannabis cultivation facilities concern volume usage limitations and wastewater quality regulations. If a facility is regulated on water quality that can be discharged into the sewer, the agricultural runoff water must be processed with a variety of methods. These methods include:
If a municipality regulates a facility’s daily water volume usage, that facility must pursue one of the following:
The potential regulations create an incentive for many cannabis producers to seek ways to create a facility with “Zero Liquid Discharge,” however there are many associated challenges with building these types of systems.
Moving toward Zero Liquid Discharge means moving away from the traditional horticultural method of relying on “drain to waste” systems. The runoff from a drain to waste system is sent literally down the drain into the sewer system, which is of main concern for regulators. A closed loop system is possible, however input costs would be extremely high compared to a traditional efficient drain to waste system. A system that can recycle all runoff water on a large scale must be extremely specialized and the facility must be engineered around this concept. Closed loop systems require constant water testing and at some point require some sort of wastewater discharge, which then may also need to be processed further.
As an alternative, processing run-off water on-site for recycling and volume reduction is used by a variety of industrial facilities. Using reverse osmosis to filter wastewater is the least energy intensive and most economically sustainable way to remove dissolved solids from runoff water, however this application produces concentrated wastewater that must be trucked off-site or evaporated.
Since water supply and quality can vary widely across geographic locations, so far there does not seem to be any consistency with what wastewater disposal regulations municipalities are enforcing on indoor growers. Each municipal water treatment facility's equipment responds differently, depending on what that municipality's customers are putting down the drain. Each facility will need to contact their municipality to find out what restrictions are put in place and how they will affect the permitting process. We have already seen that municipalities can vary from needing to treat the wastewater for biological control, balance the pH, or basic sediment filtration, whereas other municipalities effectively try to ban indoor agriculture by banning any wastewater disposal due to the high amount of nitrates, salts, or TDS being put down the drain and damaging the municipalities water treatment equipment
Example of a basic Wastewater Treatment System needed in order to pass regulations:
Facilities dealing with concentrated water discharge regulations usually must truck all nutrient runoff water off-site. Many operations pay for this water to be taken away by the gallon. However, one way to minimize the liquid discharge of the facility is to use reverse osmosis to further concentrate the contaminants in the wastewater streams so that there is a smaller volume of wastewater that needs to be disposed of less frequently.
The most efficient way to deal with wastewater is to use Reverse Osmosis to concentrate the contaminants as much as possible and then send the concentrated wastewater to evaporation or trucked off for safe disposal. This reclaim system is the most economical solution to minimizing wastewater and water usage. The flow chart below outlines the basic concepts involved with our Hyper-Logic Reclaim system that is designed to minimize wastewater discharge from a facility.
Our modular Nutrient Runoff Filtration System can be added to any operation to reclaim the nutrient runoff or final flush water for reuse. Water that would normally sent down the drain can now be reclaimed and reused, reducing the total water usage by at least 50-80%.
Yet another option is a wastewater evaporator, which is extremely energy intensive and will produce waste in the form of sludge/solid that must still be trucked off-site.
Integrating reverse osmosis and distillation/evaporation is the most economical way to truly achieve Zero Liquid Discharge, however, it is still extremely expensive. These systems are most efficient when treating large volumes of water, which makes them the most suitable option for extremely large commercial/industrial operations. This means that most facilities need to take the approach of saving water by altering their growing methods to use as little water as possible, and then minimizing the volume to be shipped offsite for treatment.
We work with one of the top evaporator companies that can help you get to zero liquid discharge. Here is an example of an evaporator that can be integrated into a facility that can dispose of all the wastewater produced on site.
While the above methods are all industrial solutions to treating agricultural runoff water, there are a few biological solutions as well. The main contaminants in the runoff water must be analyzed and in many cases this water source can be treated with artificial wetlands. In an artificial wetland, water with dissolved nutrients enters into the system and a variety of bacteria, plants, and other organisms convert the nitrogen based fertilizers into actual biomass. This is a great solution for any facility that has proper permits and land to do this. The problem is that these types of systems do not work in an industrial area where there isn’t land area available.