Costa Maya, Xcalak and Mahahual (Majahual) Business pages - Technology |

Building - Water - Sewage


Building Goto top

General

When building on the Costa Maya it is important to take into account the environment. The temperature, humidity, storms, land elevation etc. can influence the design in every aspect. In the technology described below it is assumed that the construction should be strong enough to survive storms even when the elevation of the land is low. This can't prevent damage but at least the construction will not be destroyed completely.

The methods and dimensions described below can been seen as an example. Of coarse you can always use more steel, stronger concrete etc. It is important to be advised on the local situation by an building expert.

Foundation


The foundation is normally a 1 m wide, 20 cm thick, base made of poured concrete of 180 kg/cm2, with 1/2" steal in each direction. Under this base square stubs of 40 x 40 x 40 cm with 4 pcs 3/8" steal are placed the prevent sliding of the base.
The foundation needs to be well below ground level to prevent mayor storms and waves moving the building. The depth depends on the natural elevation of the land. When the land is low the depth should be at least 1.5 m.

On the base a brick wall with poured concrete beams are placed. The beams are placed on all corners, top and wall intersections. The concrete is 15 x 15 cm, 180 kg/cm2 with 4 PCs 3/8 steel and 1/4" stirrups at every 25 cm. The wall is made of concrete blocks of 15x20x40 cm which are filled with concrete of 150 kg/cm2 to prevent water penetration. The foundation wall is reinforced with 1/2" steel.

Often the foundation is used as a cistern to collect rain water. The construction as described above can be used. However because of the high water pressure on the base of the wall you might want to consider solid poured concrete foundation walls of 180 kg/cm2. Make sure the cistern has an overflow outlet.

Walls

The wall is made of concrete blocks of 15x20x40 cm of 150 kg/cm2 to prevent water penetration. Poured concrete beams are placed on all corners, top and wall intersections. Around each window and door the frame is made of the same poured concrete beams. The concrete is 15 x 15 cm, 180 kg/cm2 with 4 PCs 3/8 steel and 1/4" stirrups at every 25 cm.

Arches can be created in two ways. The best way is solid poured concrete with steal in a pre-formed arch model. It is cheaper to build the arch from concrete blocks and cover them with concrete. However this method has the risk of tiny cracks after 10 or 15 years.


Roof

The roof can be constructed of different materials; palapa or concrete. Palapa is a rustic natural material that will attacked visitors. The palapa construction is not very strong in case of storms and does not keep out mosquitos very well. There fore it would be advisable to use it combination with concrete. Also a palapa roof is not very suitable to collect rainwater.

The concrete roof can be flat or sloped. When the roof is flat is normally surrounded by a small wall on the roof. When sloped it is often topped with typical Mexican roof tiles.

The roof is constructed of prefabricated concrete beams that are connected to the beam on top of the wall by means of steal. This is important to prevent the roof being lifted from the construction by a storm. Between the beams concrete blocks of 20x25x56 cm are placed and finished with a layer of concrete. In case of a sloped roof on top of that the roof tiles can be mounted.

In case of a flat roof the water drain is mounted in the lowest corner of the roof. The piping can be run outside of the wall. In case of a slopped roof a drain system can be mounted on the lowest part of the roof. It can be handy to have a valve in the drain pipe. At the first 10 minutes of rain the valve can be set to let the water run outside the cistern to prevent particles from entering the cistern.

Palapa

Palapas are generally designed and built by the palapero who builds them. They know the slope required for adequate water shed. Less than about 45 degrees generally leaks.

A sun shed has a lot less leaves installed than a house roof top.
Tying the palapa leaves should be done with strips of the same palm leaves not with jute twine, Jute doesn't stand up well to mildew.

For example a circular or square conical 9 ft palapa should cost less than 80 to 100 USD's, all material included. Construction takes a couple of days at most.


Road

Normally road construction means removing the vegetation and in some cases raising the land a bit with sand.


Water Goto top

Supply

On the Costa Maya there is no water system available. You acquire your water in the following ways:

A. Rain water

There is about 1200 mm of rain in the Costa Maya area. Depending on the size of your roof you can collect a certain amount of rain water. This rain water is clean enough to drink. This amount of rain might be sufficient for a house but is normally not sufficient for a hotel. It is a good practice to prevent other materials from getting into the cistern by adding a filter in the roof drain. Also you can place a 'two way valve'. Initially the valve outputs to the ground. The valve is put to the cistern position after enough rainwater has cleaned the roof.

B. Well

The second option for drinking water is to use a well. If you build near the coast there will be fresh and salt water in the ground. You need to find the fresh water for your well. Often this is a water 'lens' of 20 to 40 centimeters floating on top of the salt water. When draining your well make sure to drain slowly and not to drain any salt water. Drinking salt water for a prolonged period of time is unhealthy!.


C. Delivery

If your (drinking) water has finished you can order a truck with water. Because this is hugely expensive this is only done as a last resort.


You can read more details on water collection in the following books:

"Rainwater Catchment Systems for Domestic Supply"
Author: unknown
ISBN: 1-85339-456-4

"Rainwater Harvesting"
Author: unknown
ISBN 0-946688-22-2


Storage

Storage of the water is normally done in the cistern of the building. It is possible to use several water tanks to store water. However in that way only a limited amount of water can be stored.


Cleaning / Purification

Rain water and well water does not have to purified. However when you are located in Xcalak village you have to be aware that some sewage can enter the natural water system and testing the water is a sensible practice.

It is always sensible to use a filter to filter out the minute solid part that came into the cistern from the roof. This can be done with a simple filter. It consists of a tube filled with a leather/sponge like filter material. This filter needs to be cleaned at least once every 6 months. For further filtering you can use a carbon filter. Normally after this filter slightly polluted water is potable. Both filter systems are widely available in Mexico.

In the situation were the water is very polluted you can either buy drinking water or purify it with a special purification system. These system require a huge amount of energy and are there fore not very useful in the Costa Maya.


Testing

Testing the quality can be done in a laboratories or you can do this with a test kit. These kits are available from several suppliers. You only have to test for bacteria and salt levels.

You can order these kits at: http://www.thewatersite.com


Pressurizing

A. Gravity system

You can use a simple gravity system to pressurize the water of your building. The pressure is fairly low but the system is very simple. Construct a voluminous space as high as you can (at least 3 meters higher than the highest user). With a pump and level switch to control the pump you keep the tank filled. You can use the black prefabricated round plastic vessels for this purpose. Be aware that the gravity system gives a low pressure and that therefore the use of water saving shower heads etc. is often not possible. Also modern washing machines might not work on the gravity system. By adding a small pressure pump just before the washing machine you can solve this.


B. Pressure system

With a pressure system you pressure a vessel with a pump that is controlled by a pressure switch. The pressure vessel can have different designs. Most of the time there is a bladder inside. This bladder is pre-pressurized with air (with a foot pump to pump up car tires for instance). This method has to be used because water can not be compressed. In stead the air above the water in the pressure tank is pressurized and drives out the water under pressure.


Sewage Goto top

On the Costa Maya there is no sewage system available. To treat sewage different types of systems can be used. The most used way is a septic tank.

One step 'Braun' water system design

In the one step system all sewage is collected into one septic tank. The septic tank has an outlet into the ground.


Two step 'Braun' and 'White' water system design

In the two step system all relatively clean sewage from the showers and sinks is collected into a grease trap. The grease id filtered out to prevent that a layer of grease will float on top on the water in the scepter tank. The water from the toilettes is is collected into the septic tank. The septic tank has an outlet into the ground.


Three step 'Braun' and 'White' water system with water garden design

In the three step system all relatively clean sewage from the showers and sinks is collected into a grease trap. The grease id filtered out to prevent that a layer of grease will float on top on the water in the septic tank. The water from the toilettes is is collected into the septic tank. The septic tank has an outlet into a large basin. This basin contain soil. In the basin the septic tank outlet water is isolated from the groundwater. The biological activity in the basin will further degrade the pollution and kill bacteria. On the basin plant can be grown. The outlet of the basin runs into the ground.
The three step system is the best but also the most expensive system.



Sceptic tank desing

Centro Ecologico Akumal

Located in Akumal and they are doing many environmental promotion in
development of the area. For recommended on technology and books on greywater
systems and on composting toilets. They are also in the process of setting up some
demonstration/experiment sites.

Director: Kate Robinhawk
email: ksr@caribe.net.mex
Web: http://ceakumal.org

You can read more details on sewage treatment in the following books:

"Create an Oasis with Greywater" (4th ed.)
"Branched Drain Greywater Systems"
"Builder's Guide to Greywater"
Author: Art Ludwig
ISBN: unknown

"Residential Water Re-Use"
A
uthor: Murray Milne
ISBN: unknown


'Braun' and 'White' water system use

Besides building a good treatment system it is also important to use and maintain it correctly. Never use cleaning agents like Chloride or Ammonia, also prevent to much salt water coming into to the system. These chemicals will stop the biological degradation of the sewage in the system which brings an and to the treatment.

For environmentally safe laundry detergent read more details on: http://www.bio-pac.com


Energy Goto top

Gas

Try to apply gas as much as possible. Electricity is not available so try to save on generator power where possible. You can have the following run on gas:
- hot water
- stoves
- fridges
- freezers

Be aware that it is not allowed to have gas pipes running inside walls. Take this into account in your design. You can use one large gas tank or use several smaller ones.
The gas supply car comes every ?? days to refill?


Electricity

Try to apply electricity as little as possible. Electricity is not available so try to save on generator power where possible. Try not to use or allow the following electrical machines:
- ironing equipment
- coffee machines
- hair dryers

Use light fusing to prevent these electricity monsters. For lights use power saving bulbs. This reduces the energy use 5 fold!

To generate the electricity you can use the following systems:

- Generator

The generator is the most chosen option in combination with solar cells and batteries. The advantage is that the noise from the generator is only on certain times of the day/night so you are not this. Diesel is cheaper to run than Petrol.


- Solar cells

Energy systemSolar cells are quiet, simple and the sun is always there, however solar cells are expensive and are easily stolen. You need a battery system to store the energy for the night. Realize that batteries only have a life span of a couple of years.

 

 

 

 

 

 

 


For your solar system you can ask detailed technical and pricing questions to Jorge de Dios on email:
ecohome@prodigy.net.mx

The general price range of solarcell systems in 2003 is approximately:
Click on the chart to view a larger version



- Wind

Wind generators are not the first choice. They are more expensive, need more maintenance and produce noise. For a high requirement of energy wind power might be a solution possibly in combination with solar cells.


Energy saving

- For lights use power saving bulbs.
- Don't use airco but make use of the ever present Caribbean breeze.

Thank you Judy and Tom Hagmann for your input on this page!







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