- Plant debris (grass clippings, weeds, mulch) - all high in cellulosic materials
- Fertilizers - both nitrogen & phosphorus
- Pesticides & herbicides - from gardens
- Hydrocarbons including oil & fuels - parking lot runoff
- Untreated wastewater can happen especially during flood events
- Add mixers and aeration - this is key to successful reservoir management with all pollutants. This should be the first step - especially in low flow/mixing reservoirs.
- Keep pollutants out - either physical or planted barriers mimic natural wetlands that filter pollutants prior to entering water bodies.
- If algae blooms are still a problem, you can add biological/chemical controls.
Biological & chemical algae controls
- Copper sulfate - most common low-cost way to control an algae bloom. Effective, but you only want to use during most severe blooms.
- Dyes to inhibit photosynthesis - not attractive and expensive.
- Bioaugmentation - using natural water heterotrophic bacteria to degrade pollutants can be a way to improve water quality. Added bacteria help maintain populations required to degrade influent carbon pollutants (measured by COD/BOD). These same bacteria also use nitrogen and phosphorus during growth, thereby removing algae promoting nutrients from the water column.
What to expect from a biological additives in an algae control program
Biological cultures help remove buildup of organics such as hydrocarbons and plant debris. With mixing and aeration, you should notice a reduction in sludge volumes and improved water clarity. The cultures are very effective in lagoons with the most eutrophic conditions. In degrading organic pollutants, you should start to see increased D.O. and lower odors. If the problem is not as much pollution and more algae blooms, you should notice lower copper sulfate or algaecide usage rates.
Overall, I don't see adding biological cultures as a single product fix for eutrophication or algae blooms. It is best to combine multiple technologies to achieve best control.