The traditional method of mixing all waste streams together
|
The “HERR” approach of keeping urine separate from the sewage
|
| Urine is mixed with toilet flush water. |
Urine is separated from toilet flush water. |
| Urine mixed with faeces is contaminated with faecal bacteria. |
Urine kept separate from faeces has no harmful faecal bacteria. |
| Faecal bacteria from septic tanks can be as high as 1,000,000 counts. This needs to be below 2000 counts to swim in. This needs to be almost zero to drink from. |
Urine that has not come in contact with faeces has no faecal bacteria. Herr Ltd will advise on optimum management to achieve maximum faecal exclusion. |
| Urine contributes 87% of the nitrogen in mixed sewage. |
Separation of the urine leaves only 13% of the nitrogen still to be treated. |
| Nitrogen as Nitrates is one of the primary causes of algal blooms in our lakes. |
Separation of urine as well as separation and composting of faeces, safely, removes 60-97% of the nitrogen. |
| Nitrogen can best be returned to the sky using a full tertiary treatment system such as a horizontal flow reed bed. |
Using urine separation significantly reduces the size of the horizontal flow that reed beds require. |
| Mixing urine with toilet flush water requires the sewage treatment plant to do full nitrification and de-nitrification. |
Separating urine from flush water leaves largely detergents, soaps and shampoo’s to be treated by a vertical flow reed bed. |
| As the future world resources of phosphate for agriculture dwindles, the mixing of waste streams will be seen as wasteful. |
Well-managed urine separation is a long-term, sustainable and safe way of reusing biological phosphates and nitrates for agriculture. |
| Chemical nitrates require high amounts of energy for manufacture and transport. As energy costs rises with the depleting fossil resources of the planet farmers will look to lower cost fertilizers. |
Locally sourced liquid fertilzer such as urine has a lower total embodied energy. |
| Lack of regulation with various toiletries and personal care products may result in heavy metals in sewage sludge. There is some concern about the long-term policy of returning sewage solids to agriculture. |
Separated urine has no heavy metals and therefore has no long – term consequences regarding heavy metals in soils in the future. |
| Wasting urine by mixing with other waste streams will continue to impact world-wide water quality because of the high cost of full treatment to remove nitrates and phosphates. |
Urine separation will become an important economic tool for sustainable agriculture in the future. |
