GREY WASTEWATER RECYCLING SYSTEM
AUTHOR: Aura Soto Núñez.
TUTOR: Q. B. P. Bertha Alicia Arizpe Cepeda.
CETis 131
Cd. Reynosa, Tamaulipas.
April 25, 2003.
GREY WASTEWATER RECYCLING SYSTEM
OBJECTIVE The aim of this project is to prevent non-optimized water usage, as well as provide a storage solution for grey wastewater for later use in green spaces or lavatories, by way of a system involving channels, collection pipes, a pumping device and storage facilities, establishing a means of quickly reusing grey wastewater. JUSTIFICATION “Life on our planet started in the water. When the water runs out, so too will life.” Short and to-the-point, this sums up very well the importance of the colorless, odorless and insipid element that has always been essential, but which today is also invaluable and above all insufficient.
Ninety seven percent of the world’s water is salt water, the remainder being found in our rivers and lakes. And with just 1% of this minority able to be used, water is therefore very difficult to purify and recover.
Current global demographic trends of poor water usage, combined with global warming, make water the prime concern in the world today.
The problem with water boils down to two fundamental factors: • Uneven distribution, • Inappropriate usage. In Mexico, nearly 12 million people lack drinking water, while 23 million lack proper water storage facilities.
With statistics showing demand increasing every day, water usage in Mexico’s future is not very encouraging. An increasing general population, together with an increasing industrial population and agricultural needs all spell one thing: that demand is rising, and resources waning.
PROJECT DESCRIPTION We must first clarify the concept of grey wastewater. This is water that is uncontaminated by organic material or industrial residues, and which does not contain a high degree of solids, used for example for lavatories and watering gardens.
The aim of setting up a local grey wastewater recycling system within the scope of schools is to put water volumes normally sent into drains into use elsewhere, for example in lavatories and green spaces. In general, a large proportion of the water that is used and sent into drainage systems ends up in our rivers, lakes and the sea. It is this scenario that prompted this wastewater recycling system, a system that requires little investment outlay, and which offers a solution to the region’s water issues.
With no project of this type currently implemented within the planned scope, demand for a system that conserves our natural resources, especially water, would appear to be high. Especially as a large percentage of the drinking water used in a variety of activities could be replaced with grey wastewater with zero consequences.
The system involves water from two fountains and bathroom sinks being collected to a 1000-liter Rotoplás tank featuring a submersible container. The Rotoplás tank is situated underneath and to the side of the bathroom facilities, and includes a pumping device that transfers the water to a storage tank situated above the bathroom facilities. The pumping device features an automatic chlorinating tank, which removes any solids and helps maintain the piping in a clean condition, as well as disinfecting the wastewater.
The water from the pump runs to the storage tank via clearly marked pipes, from where it is channeled to the lavatories. Once used, this water then passes to the regular wastewater drainage system.
In the event of an insufficient source of wastewater, the storage tank can be topped up via a drinking water source, which is then used for the lavatories. Where there is excessive wastewater, the tank also features a run-off pipe, which drains water for use in cleaning offices or garden irrigation. Over the entire system, all pipes are clearly marked.
The system undergoes cleaning maintenance operations every two months. This involves removing any solid material from basins and fountain hatches, thus avoiding any clogging.
PROVISION OF MATERIALS AND LABOR COSTS FOR BUILDING, INSTALLING AND / OR OPERATING THE FOLLOWING CONCEPTS:
CONCEPT 1. CONSTRUCTION OF TWO WATER FOUNTAINS 2. MODIFICATION OF SANITARY WASHBASIN DRAINAGE SYSTEMS 3. SANITARY REGISTERED DRAINAGE PIPES FROM WASHBASINS 4. SANITARY REGISTRATION 5. SANITARY REGISTERED DRAINAGE PIPES FROM WATER FOUNTAINS UNIT QTY Batch Batch ML Indiv. Indiv. 2 1 6 1 25 1 1 1 1 UP $5,522.00 $1,994.20 $165.20 $539.26 $165.20 $8,024.00 $802.40 $2,183.00 $1,888.00 TOTAL $11,044.00 1,994.20 $991.20 539.26 $4,130.00 8,024.00 $802.40 $2,183.00 $1,888.00
6 PUMPING DEVICE, INCLUDING ROTOPLAS TANK AND SUBMERGIBLE CONTAINER Batch 7. STORAGE TANK SUPPLY LINE 8. STORAGE TANK 9. LAVATORY SUPPLY LINE TOTAL Batch Indiv. Batch
$31,596.06
On inspection, we estimate that within the scope of the Centro de Estudios Tecnológicos Industrial Y De Servicios No. 131, water consumption stands at approximately 50 liters per capita, per day. When we consider that the school’s population including students, lecturers and administrative staff is 600, the figures are as follows:
Water consumption, in liters per person per day: Lavatories Washbasins Drinking fountains Green spaces Total 20 l 10 l 15 l 5l 50 l
This therefore puts total daily consumption at: 50 l per person per day x 600 people = 30,000 liters per day Daily drinking water consumption is therefore approximately 30,000 liters. If we subtract from this figure the amount of water recycled using our system, we are given: Washbasins Drinking fountains Total 10 l 15 l 25 liters per person per day
Our new total consumption figure is therefore: 25 liters per person per day x 600 personas = 15,000 liters per day If we subtract this figure of 15,000 liters per day of recycled water from the total drinking water consumption figure of 30,000 liters per day, we are presented with a 50% saving in drinking water.
To put an approximate monetary value on these figures, we can see that: m3 of drinking water = $10.00 Water consumption without recycling = 30 m3 X $10.00 = $300.00 per day Water consumption with recycling = 15 m3 X $10.00 = $150.00 per day Once more, the system gives us a 50% saving, this time in expenditure. When we consider that the initial investment for the system was $31,597.00, we estimate that this outlay can be absorbed in no more than six months. The community of Reynosa is home to 427 places of education, from pre-school to further education level, with an overall population reaching 110,000 students. If we extend our earlier figure of 50 liters per person per day over the entire community, we are given an approximate water consumption of 5,500,000 liters per day, or 5,500 m3. Were the recycling system to be implemented throughout, the water savings reach 2,750 m3.
CONCLUSION With the results of this analysis, it is easy to imagine the impact that this project could have were it implemented on a national scale, taking into account the overall number of schools in Mexico. Such an act would also accelerate the development of new technologies, thus improving our general quality of life and water management. We need to be aware that water is a resource that requires management, shared user responsibility and suitable administration. The secret lies in adopting the right water usage practices, i.e. GREATER RECYCLING OF WASTEWATER, by implementing systems for reusing grey wastewater.
SUMMARY This project aims at conserving water by way of a system for recycling grey wastewater. Water from washbasins and drinking fountains is contained and transported through PVC piping to a pump installation located underneath the bathroom facilities, combined with an automatic chlorination system to remove solids and facilitate cleaning the system and piping. The pump sends the water to a container tank above the bathroom facilities, which then distributes the grey wastewater to the lavatories. The tanks also features two pipes, both of which are clearly marked. One is from a drinking water source, used to top-up the tank in the event of wastewater shortage; the other is used as a run-off in the event of excessive wastewater, the surplus then used for cleaning offices and irrigating gardens. The system provides a water saving of 50%, thus contributing to the preservation of this precious resource, as well as benefiting the economy.
ACKNOWLEDGEMENTS I would like to thank the people and entities that provided me with information and support in completing this project. In particular, Q.B.P. Bertha Alicia Arizpe Cepeda, my tutor and teacher, for helping me develop the idea and offering materials and references, such as the Manual de Potabilización del Agua, by Jairo Alberto Romero Rojas; Ciencia Ambiental y Desarrollo Sostenible, by Enkerlin, Cano, Garza, Boguer (Thompson publications), Medio Ambiente y Desarrollo Sustentable, published by the Universidad Autónoma de Tamaulipas. I would also like to thank the Comisión Municipal De Agua Potable y Alcantarillado de Reynosa, especially the Project engineering department, for drafting diagrams and offering their expertise for a water tank system, as well as a breakdown of necessary materials. Thanks also to Proyecto del Río, a Mexican/American organization, for inspiring me to look into how to create a project that helps improve water quality, especially in the Rio Bravo basin. Thanks for providing me with training and reading materials on the subject of water. Finally, my thanks to SEED for encouraging me to investigate and put together this proposal on improving the management and administration of our water resources.
AP P E N D I C E S
AVAILABILITY OF WATER IN VARIOUS COUNTRIES
China Nigeria Turkey Japan Mexico UAE Indonesia Bangladesh Argentina Brazil Canada
0
2,4 2,9 3,3 4,4 4,9 9,5 13,3 20 29,1 43,3 91,7
10 20 30 40 50 60 70 80 90 100
High (greater than 10) Medium (between 5-10) Low (less than 5)
Thousands of m3 per capita per year
WATER AVAILABILITY TRENDS IN MEXICO
12 10 8
Thousands of m3 per capita
11.5
High
6 4 2 0 1995
4.9 Medium
3.5 Low
2000
Year
2025
CURRENT WATER SITUATION IN MEXICO
Valley of Mexico Northern central basins Rio Bravo Southern California peninsula Lerma-Santiago-Pacific Balsas North-east Northern gulf North Pacific South Pacific Yucatán peninsula Central gulf Southern border
0,2 1 1,3 1,4 1,9 2,9 3,4 5,1 5,8 10 10,9 11,1 28,4
0
5
10
15
3
20
25
30
Thousands of m per capita
SYSTEM DESIGN