- 1 See Also
- 2 Water Filtration
- 3 Water Cistern Design
- 4 Water Infrastructure
- 5 System Summary
- 6 Storage System Research
- 7 Current Water Usage
Using a clay pot can be an effective measure to filter out water, by mounting an un-glazed clay pot over a bucket the water will seep through the clay and drip into the bucket. It is vital the clay pot is free of cracks and defects and has been pre-soaked for up to 3 days.
Making clay pottery is very easy and methods have been around for thousands of years, the pot can be rendered bacterial resistant by painting the outside of the bucket with silver paint.
Silver paint can be made by hydrolysis using some high purity silver, a car battery and a pail of water, by shorting the car battery from the silver to the water, the silver will break down and murky the water, you then evaporate some of the excess water in order to thicken the concentration and paint the silver water to the clay pot surface.
If the water seeps through the clay pot in less then three hours then it is recommended to replace the clay pot as proper filtration is not occurring.
This process has been performed around the world with its recorded origin in china, there is no greater water filtration that requires no energy then gravity itself and results in the same level of filtration.
Water Cistern Design
1" diameter hydraulic connectors standard.
For dry-run protection for the submersible pump, current sense device may be used to turn the pump off if current draw exceeds designated value.
Wet Access: reach for float switch, grab and pull rope for submersible pump.
Dry Access: Use ladder. Careful of hydrogen sulfide if cistern leaked in from ground below. Hydrogen sulfide displaces the air in the cistern. Careful of oxygen-consuming bacteria.
Our water infrastructure consists of:
- Submersible Pump
- Long Hoses
- Float Switch Instructions
- Many (under 20) 55 gallon barrels
- Reverse Osmosis Filtration System
- Surface Pump (with Pressure Switch at 50psi and strainer)
- The well draws water in from its surroundings.
- The submersible pump pushes water from the well through long hoses to a 55 gallon barrel.
- Once the water level reaches the height of the float switch, the float switch turns off the submersible pump to prevent overflow (once the water level drops below the float switch, the float switch turns on the submersible pump).
- The 55 gallon barrels are linked to each other so as to become a single large water reserve.
- The surface pump pushes water from the reserve through the long hoses to the residential areas.
- The residential area has a reverse osmosis filtration system that cleans some of the received water for drinking. The rest of the water is used for general purpose applications without such filtration.
- Notes When atmospheric temperatures drop below freezing, the water inside exposed infrastructure will freeze and expand. The freezing will block water from moving past that point; the expansion may cause serious damage to the water infrastructure.
The temperature-time functions of the air in both the general region and specific areas are a significant factor of where and if the water system will freeze. Also, how closely packed the volume of water is and their insulation are other major factors.
Hoses are vulnerable because the cross-sectional area of the water volume is low and the volume of water within a hose line is spaced apart hence cannot effectively transfer thermal energy throughout the line. Hoses are most vulnerable when flow is zero and progressively less vulnerable as flow rate increases (because water movement improves thermal transfer within the water and new water transfers thermal energy into the insulation). Hoses should be insulated (ex. buried into the ground).
Large reserves of water are resilient to freezing because their heat capacity and rate of thermal transfer are high, but given severe freezing temperatures, long durations, and little insulation, these reserves will freeze as well. Fortunately, when large reserves of water begin to freeze, the most exposed part of the reserve freezes first to become an insulating layer of ice between the air and the water. Hence it becomes progressively harder for the air to freeze the water volumes that are deeper within the reserve. Small enough reserves should be insulated (ex. partially or fully buried into the ground).
Active parts of the water infrastructure such as surface pumps are especially in need of insulation. The submersible pump is already well insulated by being inside the ground.
A further step past insulation to prevent freezing is to add a thermal energy machine with a temperature switch to turn it on or off at designated temperatures. A critical consideration here is to ensure that fires do not occur by fireproofing the heated area (ex. with stone around) in addition to the temperature switch.
An ergonomics and energy consideration regarding water use is to insulate and heat the water infrastructure more than just to prevent freezing. Excessively cold water is detrimental for comfortable use, hence it makes sense to keep the water at or close to optimal use temperatures as practically possible. Furthermore, more energy is required to heat a colder volume of water than a warmer one, hence it makes sense to keep water cold using passive insulation techniques rather than by active heating that required energy.
Overall, extremely high levels of passive insulation are desirable to prevent freezing, improve water use, and reduce energy requirements. In extreme conditions, thermal energy machines may be required throughout the water infrastructure.
Storage System Research
Due to recent realizations of safety hazards with our current water storage system, we will be exploring other options for large scale storage of water for 10-20 people living at FeF (mostly at HabLab).
Our goals are reliable storage (well insulated and enough volume), high quality clean water, and cost effectiveness.
Current Water Usage
Current use for 15 people=400 gallons per day+400 to play it safe
24,000 gallons per month
292,000 gallons per year
Rainwater Catchment for FeF
To calculate we use this equation:
Catchment area (ft^2) x Annual Rainfall (ft) x 7.48 gallons = Total Rainwater (gallons)
3200 ft^2 x 3.42 ft x 7.48 gallons = 81,861 gallons per year
That means we are short 210,000 gallons per year if there are 15 people living at FeF year round (and we are only using HabLab runoff).
If we get equal amounts of rain every month, we will have 7000 gallons per month from HabLab's roof (5000 gal short of current usage).
Assuming that 1/8" rain is the average lowest amount of rainfall, and 5" the highest, our range of water to fall on HabLab's roof from a given event is 225-9200 gallons.
If we use 800 gallons per day, we will need at least a 2400 gallon cistern for three days storage.
- Our current storage of sixteen 55 gallon barrels amounts to 880 gallons, so 2400 should be more than enough considering we will be using a float switch to control a well pump whenever the rainwater level is below sufficient volume.
The following taken from Rainwater Harvesting for Drylands and Beyond: Vol 1 (.PDF download)
"Rainwater is naturally distilled prior to cloud formation, and thus is one of our purest sources of water. Rain is considered soft due to lack of calcium carbonate and magnesium found in solution, and is excellent for cooking, washing, and saving energy. Rainwater use reduces soap and detergent requirements, and eliminates soap scum, hardness deposits, and the need for a water softener (sometimes required for well water systems), besides being a natural hair conditioner."
A note on current well water quality: the well water is not the source of pathogens. Our storage technique is the problem, and is better suited for agriculture. I propose cisterns for short term storage of well water, and also if we choose rainwater catchment later.
Life Cycle Cost
10,000 gallons of cistern storage
Burial and/or Insulation of Cistern(s)
We need large scale, sealed storage whether we use rain or well water. Cisterns would be a fast solution to large volume water storage, as opposed to barrels.
This is an immediate solution to water storage, it would be a large cost to buy them, and also require renting an excavator to bury the cistern and pipes before winter.
Short Term Action Items
- Get a Float Switch
- Research and Acquisition of Increased Storage, either One or two large cisterns or many interlinked containers
- Research Utility Outbuilding options
- Research mobile water vehicle
- recommended by Andy Halbert
- below ground water cisterns do not exceed 1700 gallons
- Options for above-ground, polyurethane insulation and heat traces make bigger volumes possible + making digging down obsolete.
- Need to research prices