Grey water recycling pilot project under way

Expert: Reusing shower water could save between 25m.-50m. cubic meters per year.

grey water 248.88 (photo credit: Courtesy Water-Arc)
grey water 248.88
(photo credit: Courtesy Water-Arc)
A pilot project to examine grey water recycling in Israel has gotten under way recently, it was revealed to The Jerusalem Post this week. If the pilot is successful, the government would consider permitting systems in the public sector and in businesses to recycle shower water for flushing toilets or watering gardens. There is also the potential for new construction to contain grey water purification systems. Grey water is the leftover water from showers, sinks and washing machines, as opposed to black water - the water from toilets. With the proper treatment to reduce bacteria, it can be reused in toilets or to water gardens. Grey water recycling has become a hot topic around the world, with water-strapped countries like Australia and others installing such systems. In Israel, the Health Ministry has generally prohibited grey water recycling because of the unacceptably high bacteria count in the water. The pilot project, initiated by the environmental organization Shomera for a Better Environment, would only focus on reusing shower water, as there are additional problems with reusing kitchen-sink and washing-machine water, Shomera executive director Miriam Garmaise told the Post Tuesday. The collaborative project is unique in that for the first time, the Health Ministry has been in the picture from the very beginning. Shomera had attempted a grey water recycling project in connection with mikvaot (ritual baths) seven years ago, but it did not meet the standards of the Health Ministry, and Shomera decided to suspend the project. This time around, Shomera is looking to create a demonstration site at a mikve, which would exhibit the potential for the public sector. To do that, Garmaise reached out to the Technion - Israel Institute of Technology's Dr. Eran Friedler, one of the country's foremost experts on grey water recycling, who eagerly joined. Together, the two approached Water Authority Water Conservation Branch deputy department head Amir Shisha with their proposal. Shisha immediately realized the Health Ministry needed to be brought in for the project to have a chance at success, and made the connection. The Water-Arc Company was chosen to implement the project. Friedler has been investigating grey water recycling at his lab for some time and has compiled reports for the Water Authority on the topic in the past. Friedler told the Post on Tuesday that the potential water savings from grey water recycling depended on the penetration level into the population. "The savings depend on the penetration rate. We did a study in 2003 that showed that with 20 percent to 30% of households [not just public buildings] utilizing such systems, the potential annual savings were between 25 million and 50 million cubic meters of water per year. That's the equivalent of a small city's annual water use," he said. Thus far, the project is in the planning stages. The idea is to take two different types of technologies - one suitable for household use and one for municipal use - and test them on the showers of a Jerusalem mikve for about a year. The technologies themselves were not new, Friedler said, but no one has done any "real-world" testing with them in Israel. After the testing phase, Garmaise said, the intention was for the mikve to become a demo site to showcase the potential for other buildings like dormitories, country clubs or hotels and other end-users. Garmaise chose mikvaot because one of Shomera's goals is to make the connection between Judaism and the environment. However, in this case, each partner brings a different target audience to the project, she noted. "Moreover, inherent to the initiative are additional educational opportunities. The choice of a mikve as the site for a water conservation effort invites the opportunity for dialogue between Jewish precepts and concepts of environmental sustainability. "This is a prime example of Shomera's ongoing attempts to inspire new population groups to join the environmental community by illuminating those places where Judaism and the environment meet," she said. Garmaise added that she was still looking to raise the final necessary funds for the project. The Health Ministry, meanwhile, got involved with the project because they were afraid that more people would attempt to reuse their grey water on their own because of the water crisis. "We became involved because we were afraid that people didn't realize how many disease-causing bacteria there are in untreated grey water. People are under the mistaken impression that one can just use grey water without treating it first, and that is not true," warned David Weinberg, national planning and treated-effluent engineer at the Health Ministry. "Studies have found that there are millions of pathogenic microorganisms in 100 ml. of grey water. It has to be treated before it can be used," he explained. Weinberg greatly stressed that the pilot project was not intended to pave the way for private grey water recycling systems. "Individuals should not be putting in grey water recycling systems. The treatment needs constant monitoring that the individual just cannot provide. Rather, the idea is for local authorities or businesses to take responsibility and install large-scale systems which are constantly monitored," he said. The constant monitoring that the Health Ministry demands would force someone to take responsibility for the system. While public buildings or hotels are ideal in that respect, it could potentially extend to new construction, where the municipality would monitor the building's system. "There's another potential problem with individual systems: If a contractor who does not know what he's doing installs or fixes the system, he could accidentally hook up the grey water pipe directly into the water supply and thus contaminate the entire household's water supply," he said. The Health Ministry released regulations for municipalities interested in recycling grey water last summer, but this is the first project to test the systems in real-world conditions. Another potential problem with grey water recycling is that it might reduce the amount of treated sewage available for agriculture. Israel treats and reuses 75% of its sewage water for agricultural use - by far the best rate in the world. Theoretically, Weinberg said, if too much grey water were taken out of the black water, it might be a problem. However, he said, that day was far off, if it arrived at all. The Water Authority has been pushing this idea for awhile, Shisha said, as part of long-term efforts to conserve water. "We've invested a lot of money in researching the issue. Eran researched it quite a lot for us since 2000. I don't see it happening tomorrow morning, but people want it, and it can save water in the long run. In our half-desert country, we should also be doing it. "Until last year, the Health Ministry had pretty much ignored grey water recycling, so it was very important for me to bring them in to give the project the best chance for success," he said. The two general types of technologies to be tested will be a biological filter designed for small consumers and a combined biological treatment and membrane filter for larger projects, Water-Arc CEO Ilan Katz said. Both are systems developed to treat black water. Grey water has about one-third to half the contamination that black water does, according to Katz. An individual system without the monitoring that the Health Ministry would require would run about NIS 10,000-20,000, he said. The monitoring system would add several thousand more dollars, he said. The larger units are more cost-effective, according to Katz, and would repay investment in a fairly short time. Katz said he hoped the pilot project would "reduce the fears, raise awareness and really give the issue a push." Despite its setback seven years ago, Shomera never stopped thinking of its mikve recycling as a flagship program. "This unique collaboration of so many different sectors could lead to a great contribution to saving water in Israel. It will add a lot of information not available today and a lot of real-world experience," Garmaise said. She will be outlining the project publicly for the first time on Wednesday at the Society for the Protection of Nature in Israel (SPNI) conference in Jerusalem.