Development of Workable Solutions for Graywater Reuse in Jordan
Prepared by Stephen McIllwaine, 2005
Translated to Arabic by Majd Musa
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This report is part of the CSBE Graywater Reuse project, a project funded by the Enhanced Productivity Program at the Jordanian Ministry of Planning and International Cooperation and by the British Embassy in Amman.
Table of Contents for the Report:
- Children's Playground in Shmeisani
- Rural Applications
- Ablution Water from King Abdullah Mosque
- Low Cost Bathroom Water Reuse in Amman
- Test Scheme at JUST
- Misguided Villa Sprinkler System in Amman
- Donor Funded - INWRDAM Project
- Donor Funded - WEPIA Project
- RSCN Nature Center
- BF House - Amman
- Ghuwaybah Mosque
- Khattar House at al-Adasiyyah
- Khaled House at al-Himmeh
- Al-Adasiyyah Girls School
- Research on Existing Practices
- Development of Demonstration Unit
- Adaptation of the CSBE Design by the Community
- More than Houses - Propagation of Graywater within the Communities
- Examples of Community - Designed Initiatives
- Installation of a Demonstrative Graywater Reuse Units in al-Adasiyyah and Ghor al-Safi
- Conclusions from the Work in These Rural Communities
- Effect on Wastewater Collection Network
- Effect on Treatment Plant Performance
- Effect of Reduction in Quantity of Wastewater
- Constraints to Widespread Reuse of Graywater
In September 2002, CSBE received a grant from the Ministry of Planning's Enhanced Productivity Program to investigate the use of graywater reuse in a domestic context, and determine how such techniques could be applied in Jordan. The project objectives included;
A. Examination of existing applications of graywater reuse in other countries, and evaluation of their technical, social and economic feasibility.
B. Investigation of the social, economic, climatic and other environmental factors that may have a bearing on the implementation of graywater reuse systems in Jordan.
C. Development, in conjunction with Jordanian professionals, graywater solutions suited to the particular context of Jordan.
D. Support of the implementation and the carrying out of studies of a number of graywater reuse systems and schemes in Jordan, as far as possible within the project's time frame.
E. Design suitable promotional material to disseminate practical information on graywater reuse to developers, construction professionals, and the interested public.
This component of the project lasted 12 months, from September 2002 until August 2003, and the deliverables were;
1. A report on graywater reuse in other countries, (Graywater Reuse in Other Countries and its Applicability to Jordan, CSBE, 2003).
2. An assessment report of graywater reuse schemes in Jordan (A Report on Graywater Reuse in Jordan).
3. Guidelines on the reuse of graywater in Jordan (Preliminary Guidelines for Using Graywater for Irrigation).
In September 2003, funding was received from the British Embassy Small Grants Programme to continue investigation of the suitability of graywater systems, particularly in rural areas. This additional funding has allowed sustained interaction with rural communities in the north of Jordan and the Jordan Valley, and further assessment of schemes in rural contexts. This funding also allowed CSBE to present graywater reuse to professionals and practitioners at workshops and conferences, and to further the sometimes controversial debate on graywater reuse in Jordan. This period of the project lasted from September 2003 until June 2004. This report is a deliverable of the final phase of the project, and contains an account of the activities concluded.
2.0 Existing Graywater Reuse Applications in Jordan
During the project, CSBE discovered a number of already existing examples of graywater reuse in Jordan. A number of these were documented in the 1st project report (Graywater Reuse in Other Countries and its Applicability to Jordan, CSBE, 2003). They are noted here for completeness.
2.1 Children's Playground in Shmeisani
One of the simplest examples is at a children's playground in Shmeisani, where the spillage water from a drinking fountain unit is captured and taken to irrigate a single shrub adjacent to it. Since the water is very clean, and there is no human contact involved with the graywater, the system is basic yet effective. There is no need for filtering or treatment of any kind, and there are no adverse effects on the plant.
2.2 Rural Applications
Numerous examples of simple graywater reuse in village households in rural Jordan were discovered. In these, water from the kitchen sink and sometimes other washbasins is applied directly to soil in the garden. There is often little or no filtering, and no other treatment of the graywater. These examples of simple, low cost, user-driven graywater reuse indicate both the need for additional water sources, and the ease with which simple applications can be developed and maintained. Many examples were documented in the previous project reports.
The advantages of such systems include their low-cost (often little more than an additional piece of pipe work), and their ease of use. Little or no maintenance is required, and the user is in full control over the system at all times. An additional advantage (often the prime incentive in low-income contexts) is the reduction in demand for septic tank pump-out, which represents a tangible cost saving to the householder over the year.
These simple systems do have some disadvantages. Since there is no treatment or fail safe system, it is important that the householder will take care not to dispose of substances harmful to plants (such as bleaches and other strong cleaning agents) into the graywater system. With no filtration (other than perhaps the coarse screen at the sink drain), much organic material (particularly from the kitchen sink) enters the system, and a number of such reuse sites were found to contain elements of organic food waste in the irrigated area. There is a potential health risk from these, although since the bacteria quickly die in healthy soil, and the household waste is generally used within the property, the risk is small.
Overall, it appears that in some areas of Jordan, where water is particularly scarce, forward thinking people have developed simple ways of making their water go farther, by reusing a component of their domestic graywater. Solutions are low cost, involving no complex technology or materials. Risks to plants are managed by controlling inputs to the graywater, and risks to human health, already small, are minimized by common sense care over how the water is used. This is water demand reduction by necessity, and backs up the argument for encouraging graywater reuse on a wider scale in Jordan. It works, it is easy to use, and, for some at least, it is worth the effort.
2.3 Ablution Water from King Abdullah Mosque
At the King Abdullah Mosque in Amman, wastewater from the ablutions of worshippers is collected, pumped to a rooftop storage system from where it is filtered and reused to irrigate fairly extensive areas of ornamental plants in the grounds of the mosque. The system has been operational for a number of years, and has resulted in a significant saving on the mosque's water bills. Since the water used for ablutions is of a relatively high quality to begin with (it has very little soap content), there are no adverse effects whatsoever on the plants.
Water quality testing on the water before and after filtering showed very low levels of contaminants in the graywater to begin with. As discussed in the previous reports, based on the requirements of JS 893, the Jordanian Standard governing the quality of treated wastewater used for irrigation, graywater from this mosque would have been suitable for the irrigation of cooked vegetables and fruit trees, or of ornamental plants in the grounds of the mosque, even before filtering.
2.4 Low Cost Bathroom Water Reuse in Amman
A number of private householders in Amman were also found to have installed graywater system of various kinds. One good example is the HB house in Amman, where graywater from one bathroom in the house was intercepted at an external manhole and taken to a horizontal 2" PVC underground pipe with holes arranged at intervals, supplying the water to a row of plants. There is no pumping or filtering of any kind, and no change of behavior was necessary on the part of the householders since all the water from the bath, shower, and bathroom sink is applied directly and automatically onto the plants. This system has been operating for 3 years now and there are no signs of stress on the plants or the soil. The cost of the manhole divert and the piping are reckoned to be of the order of 20JD, and there is little or no ongoing maintenance required. A fuller discussion of this application is provided in the previous project reports.
2.5 Test Schemes at JUST
The Jordan University of Science and Technology (JUST) has experimented with the use the graywater from one of the accommodation blocks housing female students. The graywater is collected at an external manhole and taken to 2 underground storage tanks from where it is pumped to an irrigation area. This work has been written up in Qaqish, LM, ‘Effect of Grey Water Irrigation on Soils and Crops', MSc Thesis, Jordan University of Science and Technology, May 2003. One interesting feature of this project was the inclusion of a reed-bed treatment system to treat a component of the graywater. Untreated graywater was released into the reed bed and was captured downstream. The ‘treated' graywater was stored in a third tank for later reuse.
Fava beans, spinach, and carrots were grown in controlled areas. A component of the area was irrigated with the untreated graywater. A second area was irrigated with the treated graywater, while a third was irrigated with mains water. The scheme was irrigated over a period of 5 months and tests were completed on the water, soil, and the plants irrigated. The main conclusions are that the reed bed was successful in significantly reducing the amount of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), turbidity, nitrates, and bacterial content. However, this application is suited more to larger scale use than single-household domestic reuse.
2.6 Misguided Villa Sprinkler System in Amman
A second, very different system was observed at NN house, also in Amman. This recently built house was dual-plumbed during its construction, and a dedicated underground collection tank and treatment system was installed. Graywater was collected from a number of bathrooms and sinks, excluding the kitchen sink, but including the washing machine. The collected graywater was filtered and pumped through a sprinkling irrigation system. However, this system, although designed and installed as an integral part of the house, was abandoned within the first two months of operation due to adverse odors from the irrigation water. A basic principle of graywater reuse is that stored graywater will smell, and that graywater should not be sprinkled. By making some minor adaptations to this system, it would be possible to have it working successfully.
2.7 Donor Funded - INWRDAM Project
For over a decade, Care International, in conjunction with the Inter-Islamic Network on Water Resources Development and Management (INWRDAM) has been distributing and installing graywater units to villages in rural Jordan. These units consist of piping to capture graywater from the dwelling, plastic barrels for graywater treatment, an automatic pump to take the graywater to the irrigation system, and irrigation piping and valves.
In the 2-barrel system, graywater drains by gravity from the household into the first barrel where settlement of solids and separation of grease occurs. Water then passes to the second barrel through a fabric mesh filter, from where it is pumped into the irrigation distribution network. The barrels are sealed, eliminating the release of odors. A float sensor activates pumping of the graywater once the graywater level reaches a certain level. In the 4-barrel system, the two additional barrels contain a gravel medium through which the graywater passes in an upward direction. Anaerobic digestion occurs in these barrels, to produce a higher quality effluent.
The benefits of the 2-barrel system lie in its ability to remove greases and solids from the graywater, including organic material. Grease and solids removed from the graywater are contained within the barrel system and are removed manually during periodic maintenance. The 4-barrel system also allows for anaerobic treatment, although the need for this is questionable, given that the resulting water will be used for irrigation of plants growing in soil.
The main drawbacks of these systems arise from their complexity and cost. Although many of the components (plastic barrel, plastic piping) are available locally and inexpensive, the pump and float sensor considerably increase the cost of the system. Pumping graywater, even after filtering, through a pump will give rise to a pump maintenance requirements, through time. Additionally, the power requirement of the pump (even though it may only be required for a few minutes each day) will increase the ongoing costs of this system. The treatment provided in these systems will not remove chemical contaminants, and a degree of care therefore is assumed on the part of the householders. Through time, as the effective maintenance and running costs of these systems are recorded, a fuller assessment of their suitability for a low-income village environment may be made. These schemes are discussed more fully in the previous reports (A Report on Graywater Reuse in Jordan) and (Graywater Reuse in Other Countries and its Applicability to Jordan, CSBE, 2003).
2.8 Donor Funded - WEPIA Project
A more recently implemented donor-funded installation has been visited and assessed during the final phase of this project. Around 20 graywater units have been installed in various houses in the village of Shuqayrah in the Karak Governorate, as part of a project to develop the village as a model for energy and water conservation. The units were designed by the Amman-based Al Safa Company and funded by WEPIA. The installations occurred during late 2003 and early 2004, and most of the projects have been commissioned only recently.
Figure 2.1 shows one of the units. The units consist of an inlet pipe, which takes graywater from the kitchen sink and bathroom sinks. The system consists of a pump and three 325-liter plastic barrels. The first barrel receives the graywater from the household, and contains a fabric screen filter. Graywater is pumped from this barrel to a second barrel which contains a sand/gravel filter. This removes solid material including much of the organic content. A third barrel contains a zyolite/fugicite medium, which acts as an active filter and reduces the organic content further.
The 2nd and 3rd barrels are sealed since the graywater requires pressurization to pass through the sand/filter and the zyolite. There is a return from the third barrel, which returns a component of the filtered graywater back into the first barrel, as the capacity of the pump is higher than desired for this system. The remaining graywater is pumped onwards into the irrigation network.
When the system is working well, the output is a good quality treated wastewater, suitable for irrigation of plants. However, because the graywater is allowed to drain to a low level in the first barrel, it requires to be pumped through the other barrels and out into the irrigation system, which is at a higher level than the invert of the first barrel. Most of the houses observed had irrigated land at a significantly lower level than the initial invert of the graywater, and would otherwise need no pumping. The design has succeeded in making what could have been a simple, gravity driven system, into a complex pressurized system.
In addition, the graywater is passed through two in-series filters which remove components that do not need to be removed. Although no water tests were conducted, domestic rural graywater which does not contain laundry water should be of a fairly high quality, given the degree of filtration to which it is subject. However, graywater which is being used to irrigate olives and cactuses does not need such a degree of intervention - it is likely that the unfiltered graywater would have been adequate for such a use.
Also, the system is unnecessarily complex and costly. The installation cost of this system - 550 USD - is extreme in an area where household water bills are unlikely to exceed 5 USD per 3 month billing cycle. There will be an ongoing cost as the pump requires electricity and will need occasional maintenance. In addition, both the sand filter and zyolite will need periodic maintenance, and eventual replacement. Although these are not expensive materials, it is unlikely that user intervention to this degree will occur in a rural village, making the sustainability of the project questionable.
In these applications, the original purpose of graywater reuse has been lost in the interests of demonstrating its technical feasibility. The installation cost of the unit is equivalent to over 25 years worth of domestic water bills, and its cost effectiveness is so negative that it cannot be considered appropriate for such a context. In addition, the quality of the output water is unnecessarily high for water, which will be used to irrigate plants. Domestic household graywater is unlikely to present a problem to the plants being irrigated, provided care is taken as to what is put into the graywater. Neither bacteria, suspended solids, nor organic material produce a problem for plants.
3.0 Graywater Applications Assisted by CSBE
After having examined how graywater was reused in other countries, and how it is being reused in Jordan, the next step was to develop graywater solutions suited to the particular context of Jordan. The following is a summary of the different types of schemes, which were developed with assistance from CSBE. The development of these schemes began during the first phases of the assignment, and were continued and further assessed during the final phase.
3.1 RSCN Nature Center
The Royal Society for the Conservation of Nature (RSCN) has included a graywater reuse unit in its new Nature Center building it has constructed in the Jabal Amman area of the captial. CSBE assisted with the design of this unit. Graywater will come from the hand basins and kitchens of the Nature Center as well as from the bathrooms and laundry of 4 apartments that will be housed above the center. The actual quantities of graywater will depend on the usage of the center and occupancy of the apartments. The unit consists of 3 chambers, as shown. Graywater drains (via a vertical PVC pipe) to a mesh screen filter, easily removable for cleaning, which will remove coarser solid material such as hair, lint and food scraps. Graywater will then pass upwards through a graded sand-gravel filter. This variable medium will allow for further filtering of finer solids, and will provide a surface for the anaerobic breakdown of organic material trapped in the filter. The filtered graywater will appear above the medium layer and overflow into the third chamber, from where it will drain by gravity to the irrigation network. The design of the unit provides for backwashing of the filter by reverse-connecting a hose to the unit, and also contains a diversion valve which can take all graywater to the municipal sewer if necessary.
There are a number of issues of interest with this system. Firstly, the system does not serve a single family household. The Nature Center itself will be a non-residential establishment, with little volume of graywater output other than restroom and kitchen sinks. However, the building will contain 4 apartments for short term usage by guests of the RSCN and visitors. A degree of care and cooperation will need to be shown by the users of these apartments to avoid the release of strong cleaning materials and bleach etc into the graywater.
Secondly, the performance of the graywater unit itself needs to be monitored and assessed over time. The amount of solid material intercepted by the filters will be an indicator of the quality of the graywater being produced. Also, the hydraulic operation of the sand filter should be monitored to determine if it is liable to clog.
A third important issue involves the plants to be irrigated by the graywater. The irrigated area is sheltered by the Center building and as such will receive no rainfall that would have had the effect of diluting the graywater and helping reduce the buildup of contaminants released into the soil from the graywater. In addition, the architect has elected to sow the site using spores and seeds of plants native to that particular urban area of the city. Young plants are particularly sensitive to some of the impurities in graywater, and RSCN may need to supplement the irrigation with mains water for an initial period. However, the type of plants which have survived in such a polluted urban environment will tend to be more drought tolerant and resilient to graywater.
The unit has been commissioned and tested, but is currently not operational due to the odors which emit from the graywater when applied to the soil. One of the cardinal rules of graywater systems was broken - the unit allows graywater to sit stagnant before it is used. Instead of the graywater being allowed to drain vertically downward through the sand/gravel filter, the graywater is applied to its base and filters upwards. There is therefore always an amount of graywater left in the filter section. Anaerobic digestion occurs, and odors are given off when the graywater is released from the tank and applied to the soil. Discussions are underway with RSCN regarding revisions to the unit that require simple alterations to allow the graywater to drain downwards through the media filter, rather than upwards, thus eliminating the need for graywater to stand stagnant for a period of time.
3.2 BF House - Amman
This scheme is interesting in that it involves a larger urban villa in West Amman that was plumbed for graywater from its conception, in conjunction with a rainfall harvesting system. Graywater from four of the bedrooms, together with the en-suite bathrooms, and the laundry is intercepted and taken to a settlement tank in the basement. This will be pumped for use in the irrigation of approximately 200 m2 of garden area, situated adjacent to the house. The house has been occupied since March 2004 and the plumbing and graywater storage tank are in place, but the filter and the pump unit have yet to be installed. An outline of the proposed unit design is illustrated in Figure 3.1.
A guiding feature of the design was the need to provide graywater that can be pumped through a head of around 6m from the graywater sump to the garden level. Pumps work best when the water contains few solids and dissolved impurities, so it was felt prudent to include a dual filter system - a coarse screen to remove larger solid material, and a finer filter, which would remove finer solids. The filtered graywater would then be stored in a chamber from where it would be pumped to a smaller storage tank at garden level, from where the irrigation would be controlled. This pump will be operated automatically by a level sensor.
A number of other issues were taken into consideration. If there is significant organic material in the graywater that is not removed by filtration, it would begin to undergo anaerobic digestion in the settlement tank. Unpleasant odors may be released at this stage, and it may be desirable to have this tank carefully sealed with a vent to release gases at an appropriate height. Suggestions have been made that oxidation of the filtered graywater (by ozone or chlorine) may be necessary at times to halt the digestion process and reduce odors. Provision may be made for an ozone unit at design stage, although the occasional manual insertion of chlorine tablets into the tank may also be sufficient.
Also, a means of draining this tank and disposing of the graywater to the municipal sewer (or septic tank) by gravity has been included in the design. This is necessary in case the graywater should become contaminated (for example by the release of chemicals into the water) or in the case of pump-failure. A reliable control system of level sensors and pump switches would be required to prevent the overflow of the tank for any reason, or the saturation of the irrigated area.
The garden area is an artificially constructed area bounded by a retaining wall. Drainage of the area via holes in the retaining wall is permitted. However, there is a risk of the slow build up of contaminant material in the soil following the prolonged use of graywater. It remains to be seen if this is the case. Periodic flushing of the soil with mains water will reduce buildup of materials, although it is possible that the natural rainfall at the site (around 500 mm/year) will provide sufficient natural dilution.
Because the graywater will have been sitting stagnant before use, it has to be applied to the sub soul to avoid the emission of odors to air. The storage tank l also should be well sealed.
3.3 Ghuwaybah Mosque
A new mosque has been constructed at Ghuwaybah in Ghor al-Safi. The designers expressed interest in providing a means of using the wastewater from the ablutions of worshippers to irrigate a small number of trees and shrubs in the mosque compound. Figure 3.2 shows the external view of the mosque, and Figure 3.3 shows the central ablutions point, all 4 sides of which have an ablutions basin. Ablution water is generally of high quality, containing no soap or chemicals other than human hair and skin debris, dirt, and sweat, as has been seen from results pertaining to the successful reuse of water from the King Abdullah Mosque in Amman.
CSBE provided a concept design whereby water from the ablutions basins is combined and taken to a manhole in the floor of the mosque, together with water from the hand basins in the restroom area. A coarse screen filter at each of the basin drains will prevent larger solid material from entering the pipes. The graywater will drain by gravity from the manhole into 2 irrigation lines that will supply water to planted areas on all 4 sides of the mosque courtyard. The pipes were laid at a gradient and each terminated in a stone pit designed to encourage the distribution of the graywater around the plant root area. A valve was placed at each outlet. The provisional planting scheme will include palms in the courtyard and Bougainvillea around the pergola. No graywater storage or pooling will occur and odors are not anticipated.
The mosque was opened by HM Queen Rania in March 2004, but it is not yet known how much graywater is to be produced for this structure, and how the quantities of graywater will balance the irrigation needs.
3.4 Khattar House at al-Adasiyyah
A demonstration application has been implemented in the village of al-Adasiyyah at a property that already was known to be reusing graywater. In the past, graywater was manually transferred from the basin to a number of olive trees via a plastic bucket. CSBE advised on the installation of a floor drain under the sink, allowing graywater to drain to a new manhole, which was installed adjacent to the former graywater basin. This manhole is shown in figure 3.4, and is fitted with a stainless steel sieve, which will act as a filter.
Filtered graywater drains from this manhole by gravity into a new drip irrigation system installed at the olive trees. This modified graywater reuse system eliminated the need for contact between the user and the graywater, except for periodic cleaning of the filter. However, regular follow up and assessment of this unit has revealed a number of problems. After using the system for a number of months, recurrent blockage of the pipe occurred due to lack of intervention from the householder. Eventually the filter was removed and the underground outlet pipe clogged and needs unblocking. The drip irrigation system is now being by-passed and the water overflows from the manhole and irrigates the soil by surface flooding.
The householder has shown no interest in the basic plumbing required and it is not yet clear why the filter was removed in the first place. This shows the importance of householder maintenance and follow up. Although the householder was the initiator of the graywater reuse and used to transfer the water via a bucket, he has not been not active in cleaning out the filter and its maintenance.
3.5 Khaled House at al-Himmeh
Many of the houses in the northern village of al-Himmeh are ideally suited for graywater reuse, having separated plumbing already installed, and having an amount of garden area, adjacent to the house, at a level below the floor level of the house. As such, the graywater can be easily captured, filtered and transferred to the irrigation system, without the need for pumping. CSBE advised on the installation of a simple graywater reuse system at one particular dwelling. Figure 3.5 shows the pipe installed to transfer graywater form the outlet pipe to the new manhole installed in the garden. Figure 3.6 shows the manhole, together with a stainless steel sieve filter. Graywater can be seen emerging from the inlet pipe onto the sieve. The base of the manhole is filled with gravel to raise the inlet level of the manhole to match the outlet pipe and reduce the retention of graywater in the manhole. Figure 3.7 shows the installation of a new drip irrigation hose.
The design of this simple application was suggested by CSBE, but constructed using locally available materials by a local plumber (on the advice of CSBE). This installation is acting as a demonstration unit in the village of al-Himmeh, and highlights the ease with which graywater can be used in a very low cost solution. In this case, the cost includes simply the materials for the concrete manhole, a sieve, some pipe work, and labor costs. After 10 months of installing the unit, the system is working very well irrigating 10 olive trees and 3 Guava trees, thanks to the efforts of the energetic householder who carries out regular maintenance. This is the most successful graywater reuse application - it is low cost, uses appropriate technology, is useful and effective, but its success still hinges on positive user intervention.
3.6 Al-Adasiyyah Girls School
The girls' school in al-Adasiyya expressed interested in reusing graywater as part of an ongoing project on water conservation and water conserving gardens, being implemented by CSBE in conjunction with the Mennonite Central Committee and the local voluntary society. The project is a collaborative one, involving the staff and students at the school. Although there is potential for reusing graywater from a number of areas of the school, a decision has been taken to begin simply. Figure 3.8 shows a row of drinking water faucets on the school grounds, adjacent to a planted area, which have been plumbed to allow the graywater to be captured and diverted to the plants as illustrated in Figure 3.9. Since the water will be of high quality, and should contain little solid matter or organics, only a simple screen filter is being used, to protect the pipe system.
The main disadvantage of this system is the low quantity of graywater available, provided the faucets are properly closed after use. However, the reuse of graywater in such a simple, low cost way will be used to reinforce to the students the message of water demand management and to engender discussion about future possible ways to use graywater at the school and in their homes. CSBE has a continuing commitment to the school in the design and installation of water conserving landscapes, and was able to monitor the operation of this simple system. The plants at the upstream end of the graywater pipe are healthy and well irrigated, but the plants at the 'far end' clearly need supplementary irrigation.
Community involvement in al-Adasiyyah and al-Himmeh was facilitated by an ongoing project being implemented by Habitat for Humanity, together with the al-Adasiyyah local voluntary society. It is hoped that this simple demonstration application will engender discussion in the village and encourage householders to develop their own local graywater solutions, based on this design. There already has been significant positive community interest in graywater, and the establishment of such a simple, low cost yet effective solution should encourage the propagation of the idea, if there is a real demand for graywater reuse. One of the other benefits of the project has been the training given to a local plumber in graywater systems and their implementation. Interestingly, one of the main perceived advantages to this village, which is not served by a mains sewerage system, is the potential saving to be made from a reduction in septic tank clearance costs. The continuing involvement of CSBE and Habitat in this community enabled ongoing assessment. The work in these villages is discussed more fully in the next chapter.
4.0 Graywater Reuse and Propagation in Rural Villages
Technical details on the graywater schemes that were implemented in two villages of rural Jordan have been documented above. However, the process of coming up with those particular technical solutions is an interesting one, and occurred in various stages, as outlined below.
4.1 Research on Existing Practices
As noted earlier, and detailed in the first project report (Graywater Reuse in Other Countries and its Applicability to Jordan, CSBE, 2003), the first component of the project was to identify technologies and solutions for graywater reuse, which had been developed and applied in other countries. It was recognized in the planning phases of this project that the context and constraints of Jordan were such that it was unlikely that solutions that are appropriate in other places could be adopted and applied to rural Jordan. Consequently a program of visiting rural communities and determining if and how graywater reuse and water conservation in general were being applied has been carried out.
During the first phase of the project, CSBE visited the villages of al al-Himmeh and al-Adasiyyah, in the north of Jordan, in conjunction with Habitat for Humanity (HFH) and the Mennonite Central Committee (MCC). Both these organizations have had longstanding projects with the communities of these villages and have had good relations with the local community organizations and the local leadership.
It was found that many householders were successfully reusing untreated graywater with no measurable detrimental effect on plants or humans. CSBE visited and assessed a number of existing household examples of graywater reuse. However, without even a basic screen filter, solid organic material from kitchens was finding its way onto the irrigated area, and there was often a degree of human contact, which could increase the risk of contamination of the user.
4.2 Development of Demonstration Unit
CSBE therefore developed a simple low-cost demonstration unit to promote simple graywater use in such low water use environments. The kit is shown in Figure 4.1 and consists of a simple chamber inside which is an easily removable mesh screen filter. Graywater drains via an inlet pipe onto the screen. Solid material is retained by the mesh and the water passes through the screen and drains from the chamber by gravity via the exit pipe which should be connected to the irrigation network. The internal base level of the chamber can be raised by the addition of gravel or sand to match the invert level of the exit pipe, in order to minimize the retention of graywater in the unit and the consequent buildup of odors. The filter is easily removable for periodic cleaning. The CSBE demonstration unit was composed of fiberglass, so it can easily be transported for demonstration at varied locations. However, an installed unit would be more likely to be made of concrete or cinder block, and sunk in the ground.
The unit was taken to the communities and discussed in detail with local community organizations, local plumbers, and interested householders. The community was educated on the basic approach of the unit, and the advantages it would provide over the existing methods of graywater reuse in the villages. It was emphasized that, although the unit was manufactured out of fiberglass, with plastic pipe fittings, the basic principle could be translated by the community, according to their requirements and context.
4.3 Adaptation of the CSBE Design by the Community
The units subsequently installed at Khattar house in al-Adasiyyah and Khalid house in al-Himmeh represent the clearest examples of how the communities interpreted the CSBE design. Each unit consists of a concrete and cinder block manhole chamber (replacing the fiberglass box), fixed into which is a stainless steel sieve (replacing the window mesh suggested by CSBE). These units were installed in the two houses, and worked successfully.
The unit in al-Himmeh is a much better example. Here, the graywater from the kitchen sink and bathroom sink is transferred onto 12 olive trees and 3 guava trees. The scope of the system is easily visible, with the raised manhole in the center of the area of olive trees. The trees have required no supplementary irrigation since the system was installed, and remain healthy. The householder is satisfied with the system and appears able to monitor and maintain it.
4.4 More than Houses - Propagation of Graywater within the Communities
Given that the al-Himmeh example was cost effective, beneficial to the householder, and sustainable in the long term, it was considered that there was merit in propagating the use of this type of system, either by incorporating graywater into the construction of houses, or by promoting its use in the community, and letting the community take the initiative. The householder in al-Himmeh was particularly satisfied with his graywater reuse, and it was felt that if the unit was so successful and cost effective, and brought significant benefit to the householders, that some type of automatic propagation should begin to occur. After a period of 6 months, however, it was not apparent that any such propagation had occurred, so it was decided to begin a program of interaction with the communities in order to ascertain what the constraints to propagation were.
Building on CSBE's successful cooperation to date with Habitat for Humanity (HFH) in rural Jordan, a proposal was put forward for a CSBE staff member to become linked with the ‘More Than Houses' Project being implemented by Habitat for Humanity in the north of Jordan, in conjunction with the al-Adasiyyah Community Society, and local householders. The aim of this project has been to encourage and build experience and capacity in community participation.
Between December 2003 and April 2004, CSBE's graywater researcher visited homes in the villages of al al-Adasiyya and al al-Himmeh, almost on a weekly basis, in conjunction with HFH. These visits facilitated sustained discussion about graywater reuse as well as other issues, in the context of the village home and women's daily concerns and activities. The visits allowed CSBE to identify the needs and concerns of the social context. This led to proposals for the encouragement of further graywater reuse in the communities, and on the identification of constraints that limit graywater reuse propagation. Information on graywater reuse was distributed, and the simplicity and benefits of graywater reuse was emphasized.
The program of visits revealed that many of the houses in the communities had adapted the model graywater reuse applications and developed their own systems. Their adaptations are interesting to note. Firstly, instead of using 2-inch plastic pipe, 4-inch pipes were used, both as inlet and outlet pipes. This allowed the mesh filter or sieve to be dispensed with. The 4-inch pipes were considered large enough to cope with any solid material that was likely to enter the system. It is not clear why the filter was not accepted, but so far, the method of increasing the pipe diameter has not led to any known major blockages. These installations were developed by the local plumber, who had received training from CSBE's plumber and clearly had understood the principles of the system and felt confident enough to adopt it in his own way. It has turned out that the plumber has been actively engaged in promoting the system, a low key example of ‘social marketing', and a good example of how a low cost effective system can bring benefits to both the end user and others in the implementation chain. It is also interesting to note that the advantages of installing dual plumbing in these houses has been noted by the local plumbers and that new houses being built in the communities are having their black and graywater plumbing kept separate.
4.5 Examples of Community - Designed Initiatives
WK House at al-Adasiyyah
This is an example of a two-story house, already dual plumbed, with a bathroom on each floor. It has been occupied since October 2003. Graywater from the kitchen, hand-washing basin, and shower is collected and then directed via a 4-inch pipe to irrigate a number of olive trees, which are three years old. Each floor is connected separately to the system. The laundry water is also connected to the system, and the irrigation pipe is placed at different locations in order to balance the quantity of water at each tree.
This system is recent and no assessment has been made other than repeat visits, which have shown that the unit is still working.
4.6 Installation of a Demonstrative Graywater Reuse Units in al-Adasiyyah and Ghor al-Safi
4.7 Conclusions from the Work in these Rural Communities
Based on CSBE's experiences in these communities, a number of conclusions can be drawn;
The necessary starting point for graywater is a dual-plumbed house. If the house is not already dual plumbed, then graywater reuse will not be cost effective, and should not be attempted.
A key requirement for the members of the communities is that maintenance needs be as low as possible, hence the preference for 4 inch pipes over 2 inch pipes, and the preference for a system with no filter.
The householders would be more positive to the installation of graywater units during initial house construction, rather than as a later intervention, both for reasons for cost and nuisance.
The householders must take initiative and show interest in using and maintaining their systems. Even a properly installed unit has shown to be unsustainable if the user does not take the time and make some effort to maintain it.
Indications are that it is the male head of the household who feels ‘ownership' of water, wastewater, and irrigation-related issues. None of the women in the communities visited appeared able or willing to learn or take an interest in graywater reuse.
EQ House in al-Adasiyyah
EQ lives in a two-story house, with the second story used by his brother's family. Water from the kitchen, hand-washing basin, and shower drain into a simple block manhole installed by the owner. This water is used to irrigate 12 olive trees. The householder planned to install additional pipes to systemize the graywater irrigation process, and to use an additional graywater system for the upper floor in the future. Soil channels as well as an irrigation hose were used to transfer the graywater. This scheme was developed by the householder, based on the other working graywater systems in the village. However, given that open channels were used to transport some of the graywater, it was felt that this scheme represented too significant a health risk.
CSBE therefore intervened and provided an additional manhole and some 5 cm diameter irrigation pipes. A 60x60 cm concrete block manhole was installed with an outlet to distribute graywater to the trees, together with a diversion in case the householder decides not to use the irrigation pipe. In this scheme, as in all the schemes, the beneficiary was involved in the construction process. In this case, the householder was responsible for plastering the manhole and installing the metal cover. The cost of the graywater unit did not exceed 30 JOD.
HF House in al-Adasiyyah
HF lives in a 4-room house in al-Adasiyyah. One room initially was used as a kitchen and bathroom, but he was able to build a proper bathroom and a kitchen inside the house through an HFH loan.
Graywater from the hand washing basin, floor drain, kitchen sink, and the shower was directed to irrigate 20 trees (Figure 4.5), but due to the high slope of the location the graywater was not distributed to the trees evenly. CSBE, in corporation with the local plumber and the householders, added a box and irrigation pipes with valves on each tree in order to control graywater flow and distribution to the trees.
Also a new method of filtration was experimented with for this site, where two fiberglass filter sleeves were used to filter the graywater, the householder will need to clean the filters once a week. Figure 4.6 shows the new manhole and the filters.
AR House in Ghor al-Safi
CSBE, in corporation with HFH, has initiated a process of graywater irrigation reuse in other communities, including Habaka and Ghor Fifa, as well as carrying out additional projects in Ghor al-Safi. In Ghor al-Safi, AR, who works as an Imam at the local mosque and also is a farmer, recently added a new room, a kitchen, and a bathroom to his house, in corporation with HFH. CSBE, HFH, the local plumber, and the householder cooperated on the installation of a graywater reuse unit similar to the one in HF house in al-Adasiyyah, to irrigate 20 fruit and olive trees. This unit is effectively being used as a demonstration unit in Ghor al-Safi. The local voluntary society and the local plumber have welcomed the idea of graywater reuse and are very willing to propagate it in the area.
Mir'je House in Ghor al-Safi
CSBE incorporation with HFH and the local Jam'iyya, developed a graywater reuse unit at Mir'ie's house. Graywater is collected from kitchen sink, hand washing basin and a shower, to irrigate a garden that contains over 20 fruit trees. The installation took place on the August 17, 2004, by the CSBE plumber Yaqoub al-Qaisiyya and the local plumber. In this unit a new method of filtration was introduced which is fiberglass filters.
The use of fiberglass sleeves was not successful due to the use of detergents in the household. The fiber glass sleeves were worn out from the chemicals found in detergents. The graywater manhole was not covered, which caused the clogging of the pipes.
CSBE staff recommended the use of stainless steel kitchen sieve instead of the fiberglass sleeves. HFH commented that the householder should be involved in buying the sieve.
4.7 Conclusions from the Work in these Rural Communities
Based on CSBE's experiences in these communities, a number of conclusions can be drawn;
- The necessary starting point for graywater is a dual-plumbed house. If the house is not already dual plumbed, then graywater reuse will not be cost effective, and should not be attempted.
- A key requirement for the members of the communities is that maintenance needs be as low as possible, hence the preference for 4 inch pipes over 2 inch pipes, and the preference for a system with no filter.
- The householders would be more positive to the installation of graywater units during initial house construction, rather than as a later intervention, both for reasons for cost and nuisance.
- The householders must take initiative and show interest in using and maintaining their systems. Even a properly installed unit has shown to be unsustainable if the user does not take the time and make some effort to maintain it.
- Indications are that it is the male head of the household who feels ‘ownership' of water, wastewater, and irrigation-related issues. None of the women in the communities visited appeared able or willing to learn or take an interest in graywater reuse.
5.0 Implications of Graywater Reuse on a Larger Scale
Although all of CSBE's applications to date have been small, individual applications, whose overall effect will be negligible, there are questions to be asked regarding the implications of graywater reuse were it to be taken on in a widespread manner. These questions are being asked by wastewater professionals and regulators as a result of the renewed interest in graywater taking place in Jordan. In this context there are three important issues to be considered;
5.1 Effect on Wastewater Collection Network
In most countries - Jordan included - the fluid component of wastewater is effectively used as a transport mechanism to transport the solid and liquid wastes through the plumbing and sewage systems. Pipe networks, both inside the home and in the municipal wastewater collection network, are designed on the assumption that a certain amount of fluid will be present together with the solids, and will flow by gravity, driving the solids as well. The pipe diameter and gradient are designed within fixed parameters in order to maintain adequate solid transport under these assumed conditions. If the pipe diameter is too large for a particular capacity of wastewater, the fluid will lie shallow in the pipe and will not effectively move the solids. If the pipe gradient is too steep, the fluid velocity will be too high and will leave the solid material behind, causing pipe clogging.
If graywater were to be removed from the wastewater, the proportion of fluid material with respect to solid material would reduce. Depending on the balance between the remaining fluid and solid material, after a certain point, the fluid component would be insufficient to move the solid material and clogging would result. However, innovitate ways of dealing with this do exist. For example, in Karachi, Pakistan, a solution based on constructing a small settlement manhole between the location from which wastewater exits a house and enters the sewage system, is being used. Here, the solids would settle in the chamber and the liquids, which are easily transported in the system, are what move on into the sewage system. The chamber reportedly only needs to be emptied once every few years.)
5.2 Effect on Treatment Plant Performance
A second effect on the wastewater stream resulting from the removal of graywater is an increase in its ‘strength'. The contaminant component of blackwater (as measured by all relevant indicators - Biological Oxygen Demand (BOD),, Total Suspended Solids (TSS), and bacteriological content) is significantly higher than for graywater. Depending on the relative qualities, and the components of each in the wastewater stream, the wastewater from which graywater has been removed will be characterized by a much higher concentration of contaminants. This may have an effect on the wastewater treatment plant. Treatment plants are designed to deal with a particular type of wastewater influent. In Jordan, due largely to water supply restrictions, the wastewater is already around 10% more concentrated than in European countries, and a well-designed treatment plant will take account of this. If the wastewater characteristic were to change again, the treatment processes at the plant may be affected. Small increases in the strength of wastewater may be accommodated quite easily during the treatment process, but large increases may require some design modifications.
5.3 Effect of Reduction in Quantity of Wastewater
One potential benefit arising from the removal of graywater from the wastewater stream is the reduction in quantity of the wastewater. Although the strength of the wastewater might be higher, as discussed above, the reduction in quantity will reduce the load on the wastewater treatment plant. For a treatment plant that is significantly overloaded (such as the Khirbit Al-Samra plant, which serves Amman), this reduction in overall quantity will bring significant benefits by allowing an increase in the retention time at the treatment process. A paper was presented in 2003 ‘The Assessment of the Effect of Separation of Graywater from Blackwater on the As-Samra Treatment Plant', Motasem Haddadin (Ministry of Water and Irrigation, Water Demand Management Unit), which argued that the removal of a component of graywater from the wastewater treatment stream draining to this wastewater treatment plant would produce a significant improvement in its efficiency and in the quality of the effluent, despite the increase in concentration of the influent.
5.4 Constraints to Widespread Reuse of Graywater
Without additional data on the composition of wastewater in the urban areas of Jordan, and on the nature of the existing wastewater network, it is difficult to determine at what point the removal of domestic graywater from the system would become a problem. However, there are a number of constraints to the widespread use of graywater that must be taken into account. Firstly, the domestic sector accounts for only one component of the wastewater produced. Graywater reuse in the industrial and commercial sectors is less likely to occur, and the non-domestic sector accounts for a significant proportion of the total wastewater resource in Amman. Also, within the domestic sector, there is a limit to the number of households that are able to reuse their graywater. Only a relatively limited proportion of urban households in Jordan's urban areas have gardens. Only villas and the ground floor of apartment buildings will have any reason to reuse their graywater (at least for irrigation). Even if graywater reuse were to be promoted widely and receive positive and widespread interest, only a component of the total wastewater stream would ever be removed in this way, unless reuse for non-irrigation purposes such as toilet flishing, was developed.
Generally speaking, the instinctive reaction of public wastewater utilities is against allowing de-centralized control of wastewater, and their natural preference is for centralized public control over wastewater management.
Graywater reuse on a larger scale will have implications on the collection network and the performance of wastewater treatment plants. More data on water use is needed to determine at which point increased graywater reuse causes a significant detrimental effect. However, in a country where demand side management is needed, it would be a pity if inflexibility of thinking were to lead to the prohibition of such a potentially significant means of water demand reduction, given that many imaginative solutions exist to improve wastewater collection and transport. These include decentralized wastewater management and also the retention and removal of solid wastewater at the household level.
6.0 Legislating for Graywater in Jordan
During this most recent phase of the project, CSBE continued to have an involvement in the Water Demand Management Committee of the Ministry of Water and Irrigation, as it develops modifications to the Sanitary Wastewater System Code) to allow the reuse of graywater.
The committee has made a number of recommendations that CSBE does not consider to be in the long term interest of graywater reuse in Jordan. For example, the committee has decided to prohibit the reuse of graywater at the domestic level, unless there is no wastewater collection (sewage) network at the household, and none planned within the next 10 years. This effectively reduces the number of households where graywater reuse will be permitted to a very small proportion of the kingdom's population, and illustrates the inherent conservatism with which graywater is viewed within the regulatory authority. The argument for this is that significant investment is now being made at the wastewater treatment plants to treat the wastewater to levels suitable for reuse in agriculture, and that the graywater component makes an important contribution to this wastewater resource. However, it fails to take into account the benefits of a decentralized approach, and of putting the control of the water resource in the hands of the user. The benefits of centralized management of treated wastewater will go to the agricultural industry, whereas the benefits of graywater reuse remain under the control of the householder.
The committee is also drawing up proposals to have each graywater application submit design drawings of the proposed graywater treatment system, including construction details as well as details on graywater quantities and quality, and the proposed type of irrigation to be used. CSBE considers these to be significant disincentives to the easy propagation of graywater reuse, and also unnecessary. Given that the majority of households which will not be planned for inclusion on the municipal wastewater collection network within 10 years will be in rural areas, these requirements will function as a disincentive to rural householders to the extent that the code will effectively prevent any significant legal graywater reuse applications from being developed. In the meantime, interested and energetic householders all over Jordan are quietly developing and using their own graywater in ways which are appropriate, cost effective, and where the risks are minimized. If the current proposals to the code are implemented, their effect on graywater reuse in Jordan will be at best irrelevant, but if enforced properly, they actually may reduce the amount of effective graywater reuse.
CSBE continues to advocate a risk-based approach to graywater regulation, where users producing less than a certain amount of graywater and reusing it in their own households, within certain constraints, remain free of bureaucratic obstruction, and yet larger and more risk intensive applications receive the appropriate critique. This follows the Arizona legislative discussed previously.
A full discussion on the current legal position regarding the reuse of graywater in Jordan, and recommendations for separate regulation of large and small usage applications, using a risk-based approach was presented in (Graywater Reuse in Jordan, CSBE 2003).
7.0 Conferences and Technical Presentations
One of the objectives of the project was to raise public and professional awareness about graywater reuse. During the third phase of the project, CSBE was able to present its research on graywater reuse in Jordan at a number of public and semi-public venues. It has been our impression that at these events there was a clear interest in graywater reuse, but a consistent lack of awareness and understanding of the technical issues and risks involved. CSBE participated at the following events;
CSBE presented a paper at the AFESD/CEHA (the WHO Regional Centre for Environmental Health Activities) Regional Consultation Meeting to Review National Priorities and Action Plans for Wastewater Reuse and Management, (Amman, October 2003). Participants from a number of countries in the region took part in a discussion on graywater. It was evident that Jordan (and the CSBE project) are at the forefront of graywater reuse application in the region, and WHO/CEHA has extensively used CSBE's guidelines for graywater reuse in its draft guidance to the region.
CSBE provided input for a paper presented at the Water Reuse Conference, (Amman, December 2004) (organized by the Ministry of Water and Irrigation), by the head of the Water Demand Management Unit at the Ministry. CSBE staff attended this conference. Graywater Reuse is still viewed skeptically by wastewater engineers, and this conference was a useful means to put forward the case for graywater reuse at domestic scale.
CSBE participated in the Leaders' Day organized by Habitat for Humanity (HFH) and the Mennonite Central Committee (MCC), (Amman, March 2004). The event was part of HFH's 'More than Houses' project, and the graywater component of this project was presented to representatives from communities in rural areas in Jordan. A very lively and positive discussion was generated during this session.
CSBE was invited to present a paper on graywater reuse at the International Water Demand Management Conference - WDM2004, Dead Sea, June 2004. CSBE's experiences were presented and discussed at an open session. There was significant resistance and skepticism about graywater reuse as evident in the discussion following the presentation of this paper, mostly arising from a lack of understanding of the issues and an unreasonable approach to risk management.
CSBE continued to provide input to the Ministry of Water and Irrigation's Water Demand Management Committee, which is drafting amendments to the plumbing code to allow and encourage the use of graywater. There is still a resistance from the regulatory authority to adopt a realistic risk-based approach to graywater regulation, and it may be that Jordan's initial attempts at graywater regulation are burdensome and expensive to regulate, acting more as a deterrent to graywater reuse than as an encouragement. However, the argument for the risk-based approach continues to be made.
As a result of these interactions, and the significant international interest in the graywater pages of CSBE's website, a number of organizations and individuals have approached CSBE for advice on graywater reuse. For example, The International Development Research Centre (IDRC), is planning a regional course on Urban Agriculture. IDRC and CSBE have been exploring possible methods through which it would be possible to present the CSBE experience in graywater reuse to the participants of the course.
All in all, we believe that CSBE's contribution to the debate on graywater has been significant. At the initiation of the project, there almost was no public debate on graywater. No information was available, and public documentation of graywater trials or research was non-existent. There was no forum for the cross fertilization of ideas. However, at this time, graywater reuse is now firmly on the agenda for both researchers and regulators in Jordan and in the region.
8.0 List of Illustrations
Figure 2.1: The Graywater Unit in Shuqayrah.
Figure 3.1: Schematic Design of Graywater System for BF House.
Figure 3.2: View of Mosque.
Figure 3.3: Central Ablutions Point, Ghuwaybah Mosque, Ghor al-Safi.
Figure 3.4: Modified System with Filter in al-Adasiyyah.
Figure 3.5: Graywater Capture and Filtration in al-Himmeh.
Figure 3.6: The manhole, together with a stainless steel sieve filter in al-Himmeh.
Figure 3.7: Irrigation by Graywater in al-Himmeh.
Figure 3.8: Existing Drinking Fountain at al-Adasiyyah Girls' School.
Figure 3.9: Irrigated Area at al-Adasiyyah Girls' School.
Figure 4.1: CSBE Demonstration Unit.
Figure 4.2: Graywater reuse in WK House.
Figure 4.3: Graywater reuse in WK House.
Figure 4.4: EQ House at al-Adasiyyah after the installation of the manhole.
Figure 4.5: The graywater outlet at HF house before CSBE's intervention.
Figure 4.6: The new manhole and fiberglass filters at HF house.
Figure 4.7: The graywater system in AR house in Ghor al-Safi.
Figure 4.8: Drip irrigation system using valves in AR house in Ghor al-Safi.
9.0 Appendix - Graywater in Schools
As part of the CSBE Graywater Project, CSBE developed the following conceptual statement at the request of a Jordanian architectural firm that had considered incorporating graywater reuse systems in a series of public schools it was designing .. However, the ideas presented were not developed further since the incorporation of graywater reuse systems in the schools eventually did not receive approval from the Ministry of Education.
The reuse of graywater from schools for irrigation of landscaped areas is technically possible and simple to implement, provided a number of precautions are taken to minimize the risk to users of the school and to the plants and to the soil. Providing a graywater reuse solution in the design of the schools will comply with the need to provide a design that is responsive to the particular environment of the school and the associated challenges, and will complement efforts to include the passive and active use of solar energy, rainfall water harvesting, and drought tolerant landscaping. Having a graywater reuse system in a school will also provide a means to teach principles of water conservation and reuse. In case the school is not connected to a sewerage collection network, the reuse of graywater will reduce the quantity of wastewater that needs to be disposed of.
In general, graywater will be available from washbasins and sinks in the toilet areas, and from kitchen sink areas. Wastewater from toilets should not be used, nor should the wastewater from sinks used to dispose of chemicals or strong cleaning agents. The graywater should be collected and taken to a point from where it may be used to irrigate a landscaped area. A degree of simple treatment, possibly only screening, will be required. Where possible, the collection and transmission of the graywater should be gravity driven, as the use of pumps will result in additional complexity, cost, and risk. Therefore, the ideal location for the landscaped area is at a level to which the graywater can drain by gravity.
Graywater Sources and Quality
In order to avoid a complex and costly treatment system, the quality of the graywater should be considered. Water from washbasins will contain some organic material (skin, hair, and dirt), some soap components (sodium and organic fats), and a degree of pathogens (bacteria). Wastewater from toilets or other particularly polluted sources is not suitable for this type of graywater reuse, and should be diverted to the sewer system. Water from kitchen sinks, where a significant degree of cooking with fats, oils, and grease takes place, will require additional treatment and should be excluded from a simple graywater system. However, if the kitchen sinks are used for the making of tea and lighter duty food preparation, there should be less fat, oil and grease component, and the graywater may be used.
If aggressive floor cleaning chemicals are used regularly, then floor drains should be excluded from the system. Strong cleaning agents include bleaches, which will harm plants. However, if the floor cleaning uses more diluted cleaning agents and water is particularly used, the water from floor drains may be used. Floor drains close to Arabic-style toilets may not be suitable for graywater reuse if there is likely to be a significant degree of faecal contamination. This will depend of the location of the floor drain with respect to the toilet.
It is suggested that one sink or floor drain be provided for the caretaker to dispose of particularly contaminated material (paints, paint stripper, etc). The waste from this drain will not be included in the graywater system.
Wastewater from sinks in the school laboratory areas should not be taken to the graywater system, but should be disposed of appropriately.
Collection of Graywater - Dual Plumbing
Provision should be made to keep graywater and other wastewater separate until an easily accessible point, at which treatment of the graywater may occur and it would be distributed to the irrigation system. The additional cost of this separation at the construction stage is minimal, and allows final decisions on treatment and irrigation to be made at a later stage. The separation of plumbing is good practice and is required anyway by the Jordan Sanitary Code.
The treatment of the graywater depends on its quality and its intended use. Provided the graywater contains only wastewater normally associated with hand basins and light kitchen use, and it will be used only for the irrigation of plants, only light treatment should be needed. The graywater should pass through a screen or mesh filter before entering the irrigation network. This will remove larger particulates from the graywater and protect the irrigation lines from blockage. The filter should be removed and cleaned as regularly as needed to prevent backup and stagnation of the water. Depending on the solid matter content of the graywater, a devise as simple as a mosquito mesh screen may be adequate, although a finer filter, such as that used to filter agricultural water for irrigation, may be needed.
Provided the graywater passes directly to irrigation and is not handled or stored in any way, no disinfection is required.
The graywater will contain pathogens harmful to humans. It is necessary therefore to minimize the risk of these pathogens coming into contact with humans. One way is to treat the graywater and remove the pathogens. A simpler, less expensive way is to minimize physical contact between the graywater and humans. In order for the minimal treatment option outlined above to be adequate, some handling restrictions must be applied. For example, the graywater should not be handled during irrigation. The ideal system is where the graywater automatically passes directly into sub-surface irrigation lines with no human intervention needed. Graywater application by garden hose, which is manually moved around the landscaped area, increases the risk of graywater contact, and should be avoided.
In addition, the graywater should not be used to irrigate areas of grass or lawn where children or animals may play. There is a risk of contact with the graywater in this case.
The graywater is ideally applied by sub-surface drip irrigation. Surface irrigation by pooling or flooding is not advised. Sprinkling of graywater involves a high risk of contact and is to be avoided.
When removing and cleaning the filter, a procedure should be adopted to minimize the risk of the person contacting the graywater and the debris on the filter. Rubber gloves also should be worn.
As noted above, the most suitable form of irrigation is sub-surface irrigation where no contact with the graywater is required. Once the graywater comes into contact with healthy soil, the bacteria and organic components in it will begin to be broken down.
Use of graywater for irrigation is ideally combined with a landscape design and planting choice that takes into account the principles and experiences of water conserving landscaping. Intensive information on water conserving landscaping, including a significant list of plants that are drought tolerant is available on the CSBE website. Also, certain plants are more tolerant to graywater contaminants (e.g. boron, salinity) than others. More detailed information regarding this matter is available on the CSBE Website.
One important feature, which should be included whenever possible, is the ability to discharge all graywater into the wastewater system, in case of emergency. If an accidental release of a material harmful to plants occurs into the graywater system, there should be the means to immediately divert the graywater away from the plants. One diversion valve at the beginning of the irrigation distribution network would provide this.
Ideally, the graywater should be released directly to the plants with no storage. Where graywater contains organic material, once it is stored for more than a few days (or even a few hours in hot weather), digestion of the organic material begins and odors build up. One of the main complaints from badly-designed graywater systems relates to unpleasant odors. However, if the graywater is released into the soil directly, no odor is released as the soil itself begins to break up both the organic material and the bacteria.
Because of this, the graywater system should be designed and constructed so as to minimize the possibility of graywater lying in pools within the system. Ideally, all pipes and even all tank floors (if there are any tanks) should be set at a gradient to allow graywater to drain out. This is particularly important for schools, where holiday periods will see little throughput of graywater in the system. If there is pooling of stagnant graywater, odors will build up over a period of time. In other words, the system should be self-draining. If it is necessary to have pumps in the system, care should be taken to ensure that no pooling occurs inside the pump, or that the pump is cleared prior to any period of inaction.
Sodium - a constituent of soaps and detergents - has a detrimental affect on plants. In contrast, the use of potassium-based soaps provides additional nutrients to the plants. Potassium-based soaps are currently available in Jordan from the Inter-Islamic Network on Water Resources Development and Management (INWRDAM: tel. 962 06 5332993; fax. 962 06 533 2969; email@example.com).