KIT, WATER TANK, 30 m³, metal frame, storage/treatment

Tank with a metal frame, intended for the storage, chlorination and distribution of drinking water, as well as for the treatment of turbid water by (assisted) sedimentation.

Water tank

• Capacity: 30 000 litres
• Dimensions:
• Ø = 5.20 m
• height = 1.20 to 1.50 m
• Metal frame made up of 19 poles and 57 sidebars (1 extra pole and 1 extra sidebar are included in the kit)
• Liner: resistant PVC, anti UV
• 3" drain outlet fitted with a symmetric half coupling at the bottom of the tank (can be closed when not in use with the plug supplied in the kit)
• MSF logo + volume indication
• Supplied with top sheet, groundsheet and repair kit

Sludge drainage module

To be connected to the 3" bottom drain outlet. First, it is necessary to dig a trench underneath the tank in order to be able to install the drain hose.

Clear water drainage module (assisted sedimentation)

Suction hose with a strainer and a float to be connected to the tank's inner 2" outlet coupling to evacuate the treated water. Think to secure it to the frame to enable easy retrieval if necessary.

Kit content and specification varies from one section to another. For further information, contact your procurement department.

TANK

• Roof construction with pole in the middle.
• Hole for drain outlet (3") is in the bottom of the tank. Drain outlet has to be fit in the field
• Tank is reinforced on three places (120 degrees) near bottom to allow outlet to be fitted
• A hole for one outlet (3") is cut in side of tank near bottom. The outlet has to be fit in the field
• Two holes for outset (3") are marked. Outlets are supplied with the tank.
• 3 reducers (3" - 2") supplied
• Flanges are threaded (male) to allow connection with hoses outside and inside the tank
• For connection of hoses inside, elbow and Guillemin couplings are supplied with every outlet
• For connection of hoses outside, a valve and Guillemin couplings are supplied with every outlet
• Diameter: 5.40 m/30 m³, 7.20 m/60 m³
• Height: 1.50 meter (wall)
• Capacity: 30,000 l or 60,000 l
• MSF logo + volume indication
• Repair set (specific to the brand)

This tank is not suitable for transport.

For water storage

The top sheet prevents evaporation and protects water against pollution.

Choose a site for the installation

• A water tank must be installed on an even, stable and horizontal platform, accessible under all circumstances and at all times to be able to fill it
• A filled tank is heavy and needs to be installed properly at a safe location where it can't cause accidents (e.g. filled tank rolling down a slope, collapse of a building under the weight of a filled tank installed against a wall or on top of the roof…)
• The choice of the site should always be discussed with the different stakeholders

Gravity water distribution requires the "MODULE, WATER DISTRIBUTION" (see related articles below). The water tank should be located at least 1.2 meter above the level of the tap stand located close by (higher if possible) to obtain a correct flow. It is advised not to connect more than 4 tap stands to one tank, except when part of a distribution network with very regular water supply to the reservoir.

Water distribution can also be done without gravity, by means of a hand/motor pump (contact your technical department for further information).

When the water tank is installed on an earth embankment, protect its slopes from erosion with grass, stones or plastic.

In very windy areas, it is necessary to secure the tank to the ground by means of ropes tied to the frame.

Always put the water tank on its groundsheet to protect it against punctures.

Protect the tank from direct exposure to the sun by means of a roof or a shadow net.

Fence the area around the water tank.

For water treatment

Before water treatment is started, the turbidity and pH of the raw water should always be measured (if difficulties with flocculation, also conductivity and alkalinity).

Perform a jar test to determine the dose of coagulant to be added to the raw water, and extrapolate for the actual volume of the tank.

After the treatment process, the treated water should be analysed for turbidity and coagulant residuals (iron or aluminium).

It is strongly advised to order the "KIT, WATER TREATMENT QUALITY MONITORING" (see related articles below) that includes all the equipment required to test raw water, perform jar tests and test the quality of the treated water.

In case the treatment is done using PAX, a jar test is more difficult to perform. Therefore it might be necessary to measure the speed of sedimentation, and calculate the time necessary for a full tank to decant and/or conduct coagulation/flocculation tests to calculate the volume of flocculant needed for one tank.

In case the treatment is done using aluminium or iron-based coagulants, it is interesting to order the "MODULE, SUCTION SIDE DOSER" (see related articles below) to improve assisted sedimentation. This module is not to be used with PAX.

For chlorination, and distribution, the treated water needs to be transferred from the metal frame tank into water tanks with a minimum total capacity equivalent to the one of the metal frame tank.

Make sure not to suck the flocks out of the onion tank through the suction pipe.

Provide an area to dispose of sediments produced by the treatment process.

Caution

Clean and let the tank dry completely inside and outside before storing it back. Talcum powder can help to absorb the last of the humidity.

For more detailed information and instructions see also "Public Health Engineering in Precarious Situations", MSF, 2^nd edition, 2010:

• T.B. 2.16 Assisted batch sedimentation
• T.B. 2.35 Emergency water tanks
• T.B. 2.36 Installation of flexible reservoirs
• T.B. 2.37 Cleaning of flexible reservoirs.