A Rainbow Water Coalition follower asks about the perceived or actual barriers there are to emerging decentralized technologies, like residential graywater reuse....but also, generally, what factors are most important when assessing whether decentralized or centralized technologies are most appropriate.
In no particular order, the following is based on the many postings on the Rainbow Water Coalition and associated interactions with other greywater professionals:
- There is the institutional perception that traditional wastewater treatment is safer than decentralized use. There is also the issue that wastewater has enormous value and it can be resold at a large profit. There is also the sense that greywater reuse was perceived as stealing revenue and job security from the wastewater sector.
- Interference with water rights (this is an issue in Colorado and has thwarted the attempts to pass a law on greywater reuse this past year)
- Backflow prevention when greywater reuse is indoors. (Heard this directly from municipal water systems, and even though the plumbing codes address this, it is important that it be reiterated in the design/decision documents).
- Site suitability (shallow groundwater and soils - is every site suitable, is every geographic location suitable, i.e., warm weather vs. cold weather situations).
- Operation and Maintenance (filters versus other technology such as disinfection) and costs for operation and maintenance
- Is the equipment "Off the shelf" vs. "Do It Yourself" (DIY) – Some of the OSU engineering students the RWC worked with wrestled with this situation thinking they needed to build it rather than go shopping. There is more acceptance of "off the shelf" technology, and industry has recognized this with the boom in new technologies and applications that are emerging every week.
- Where is the technology used elsewhere? (Are there local case studies that one can point to, or are there national or international case studies that one can point to that are comparable to the proposed application under consideration at a particular location)?
- Cost – this is a no brainer, but the costs are highly variable dependent on size of reuse project and the technology.
- Combining with rainwater (Oklahoma and Australia permit this application, but other states don't - why?)
- Storage Safety – entry by humans, especially children (Australia had a problem with a child nearly drowning in a greywater storage bin).