“Our Silver Bullet units provide us with a consistent level of disinfection, ensuring us a quality harvest every time.”
The Grower’s Need: Effective Microbial Control for Irrigation Water
A northern California indoor cultivation facility sought an effective and innovative treatment solution for both source water and irrigation reuse.
The water treatment requirements of the facility are:
Treatment of irrigation water for risk management of bacterial and fungal water borne pathogens
Ability to capture and reuse irrigation water to meet business’ resource savings goals and to comply with regulatory requirements
Treatment technology that is compatible with hydroponic plant production, does not contribute to plant stress and mitigates crop loss
Cost-effective water treatment system that could scale with long-term plans for the business
Incoming municipal source water is delivered and stored in four black poly tanks that are located indoors under controlled climate conditions. The facility uses reverse osmosis to treat all incoming source water.
Each flower room is designed with custom rolling grow tables. Plants are grown on stationary flood and drain tables and drip irrigated with a customized blend of nutrient fertilizers. The grow tables are fabricated to allow excess irrigation water that is not absorbed by the media, or taken up by the plant, to be gravity drained from the table. The leachate drain water is collected from each table and drains to a collection tank.
Competitively Priced, Sustainable and Professionally Serviced Water Treatment Solution Impresses Grower
The grower chose Silver Bullet because of multiple benefits:
A sustainable, “green chemistry” – based solution
Proven bacterial and fungal control for other Silver Bullet customers
Professionally designed, engineered and installed water treatment systems
Silver Bullet’s service, maintenance and water analysis program
The Silver Bullet Solution: AOP and UV Combination System
To maximize the facility’s water treatment program, Silver Bullet installed its Advanced Oxidation Process (AOP) System, paired with direct UV disinfection. The combined technologies provided redundancy in disinfection treatment. The AOP system ensures the recirculated, treated water has slight residual disinfectant properties, which further aids in keeping the storage tanks clean and free of microbiological growth.
The facility uses a closed-loop irrigation system, where the required water pressure is provided by means of a pump. In this closed-loop system, water from the municipal utility, the climate control system and irrigation runoff are blended together, treated and reused as irrigation water.
Within each plant production room, irrigation water is delivered to two, vertical poly tanks. These tanks are continuously treated and conditioned using the Silver Bullet UV Treatment System. Irrigation water is then pumped to a single poly tank that is used to mix nutrient fertilizers and condition the water prior to being delivered to the plants.
Drip Irrigation Runoff Collection and Reuse
All runoff irrigation water is drained and collected in two holding tanks. Irrigation runoff is composed of several constituents that require disinfection and conditioning. Although this water allows for mineral nutrients not taken up by the plants to be recycled and reused, it also includes elevated levels of bacteria, unwanted organic content and suspended solids. Water from all three sources was continuously treated and blended into reliable irrigation water that is compatible with the facilities nutrient formula to prevent biological fouling.
Prevent Microbial Control
Silver Bullet developed an intensive water monitoring program around the production schedule for two of the facility’s plant production rooms to ensure the water treatment solution met customer expectations. For third-party validation of Silver Bullet’s performance, samples were delivered to North Coast Laboratories, a respected, state-certified laboratory located a short distance from the facility. Founded in 1975, North Coast Laboratories is a full-service environmental laboratory with a national client base and a reputation for expertise in the analysis of organic chemicals in a variety of agricultural commodities.
The Silver Bullet treated water in make-up storage tanks for both Flower Rooms A and B showed an exemplary level of disinfection, while untreated runoff water had significantly higher levels of bacteria. Analysis of Heterotrophic plate count (HPC) confirmed Silver Bullet’s efficacy in managing microbiology in the Water (Table 1).
Table 1. HPC 10-Week Average: Silver Bullet’s Success Killing Microorganisms