Time to Complete lesson: 12 min video / 35 min read

There are several types of water tanks you will need to become familiar with. The process of cleaning, sanitizing and providing filtration might differ not only because of the environment and water problems, but due to the type of tank as well.

Variations in tanks materials include:

Galvanized

Polyethylene, and

Concrete

In addition to the different materials used, you will find other tanks and variations, such as:

Tank Linings

Town Tanks

Water Bladders

Sizes of tanks can vary from 100L to 250,000L. When quoting, you will need to take into consideration both the size and how dirty the tank is to ensure you are charging a suitable price. Details on how to quote for a tank clean are outlined in Module 5: Section 4 of the Operations Manual.

We will now provide a brief technical run down on the different variations of rainwater tanks that you are likely to come across in the field.

10.1 Guidance on use of Rainwater Tanks

Through the following section, we have extracted copies of the “Guidance of Use of Rainwater Tanks 2010” document produced for the Commonwealth Government of Australia by the Environmental Health Committee (enHealth).

To access a copy, you can use the following link: http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/ eh52_aust_drinking_water_guidelines_update_120710_0.pdf

Although the guidelines may differ slightly, in PWSA’s experience, inspections of tanks can be conducted every 6-months (on request, or as part of an ongoing service), but tanks should be cleaned annually. The customer should be educated to conduct regular checks, and to call you if they identify specific issues.

This is part of the development of your business, creating a repeat customer who trusts your business and calls on you at first signs of issues.

Sections from the guidelines that may be of interest to assist you educate your customers are:

Section 6 Monitoring & Maintenance (pages 25 to 26)

“In addition to six-monthly inspections, tanks should be inspected every 2-3 years for the presence of accumulated sediments. If the bottom of the tank is covered with sediment the tank should be cleaned. It is recommended that the following components be inspected at least every size month:

Tank & Tank Roof

Internal Tank Inspection

Tank Inlets and Screens

Gutters & Roof”

Section 4: Identifying potential hazards and health risks (pages 7 to 14)

Microbial hazards

Dead Animals

Accumulated Sediments

Others

Section 5: Preventative measures and corrective actions (pages 15 to 24)

Minimize Contamination

Sources of Potential Health Hazards

Disinfection

Section 11: Community-based Supplies (page 39)

“Community based drinking water supplies need a higher level of management than those to individual dwellings”

10.2 Galvanized Tanks

Metal Tanks have always been the traditional alternative to a concrete tank, being an aboveground tank, cheaper than concrete, and lighter. Hence, easier to install.

Originally, metal tanks were fabricated from galvanized steel (steel sheets covered with a coating of zinc), which allowed the steel to be soldered together so that they could be manufactured in different shapes and sizes.

The problem with galvanized steel is that they are prone to rust. Especially if they are used with copper or brass fittings and pipes.

Manufacturers are starting to use other metals such as aluminium, Zincalume® and Aquaplate® in an effort to prevent rusting.

“Gal” tanks can come in sizes from 3,000L up to 250,000L.

10.3 Polyethylene (Poly) Tanks

The low cost of polyethylene (referred to as Poly) tanks is one of the reasons why it is among the most popular choices. They are also very light and therefore easy to transport and install.

They can experience some corrosion if exposed to high levels of sunlight, but this can take many years.

Poly tanks are manufactured around a central steel mould, coming in standard shapes and sizes.

Sizes of Poly tanks range from 100L up to 50,000L

10.3.1 Town Tanks

Town Tanks are a sub-category of Polyethylene tanks. Difference is that these are usually smaller and not used for drinking water, but for laundries and toilets or for gardens, pools and around the home.

Not only is the size smaller, but the aesthetic designs can be different too. Baffles, sections, cavities, and accessibility all contribute to the ability to clean these tanks effectively.

You may come across these types of tanks, and will need to know techniques and methods in how to clean them. Please refer to Module 4; Section 4 for details.

10.4 Concrete Tanks

The weight of concrete tanks means that they are primarily installed underground.

This can be useful in order to save space, but will obviously require significant excavation, in effect making them more expensive.

Concrete tanks are more likely to be subject to planning restrictions.

Some of the most common problems faced with Concrete tanks include;

Cracking of the tank wall/floor which is difficult to repair
Root systems working their way into the tank
Elevated Alkalinity
Skin problems, nausea etc.

10.5 Tank Linings

Tank Liners are typically used in older Concrete or Galvanised tanks. Their purpose is to protect water from leaking out of the tank, and to stop seeping into the water (such as lime from concrete tanks).

Older tanks can be expensive to remove or replace. Having a Tank Lining fitted can extend the life of the tank, and prevent contamination of the water.

Many products are available from various manufacturers, but the important thing is that they must meet Australian certification (AS/NZS:4020). This will ensure they are BPA free (BPA: bisphenol A, which is an industrial chemical that has been used to make plastics and resins since the 1960s). Therefore, limiting contamination of the drinking water.

Details of how to manage tanks fitted with linings is defined in Module 4; Section 4 of the Operations Manual.

10.6 Water Bladders

In Australia, Water Bladders are not a product commonly used for potable water storage. In fact, the only water bladders we have come across are typically used in boats where space is limited or misshaped. But we do feel it is prudent for you to be aware of these types of water storage devices.

Customers with irregular spaces might opt for a rainwater bladder. These are made from a flexible membrane that expands when water enters the bladder. Sizes normally range from 2,000L to 20,000L of water.

Typically, rainwater bladders are installed in a rudimentary frame to prevent movement, and can be installed in crawl spaces beneath the property.

But they are normally a smaller capacity than the previously mentioned fixed installations.

Water Bladders are a product Pristine Operators typically do not provide cleaning services for. If the customer is considering using a water bladder for consumption (either as a potable water solution or for grey water in household use), then a filter/sterilization system might be considered.

10.0 Types of Tanks

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Module 1 - The Franchise System

Module 2 - Administration and PODAC/ITF

Module 3 - Technical Information and OH&S

1.0 Background of the Water Industry

2.0 Australian Drinking Water Guidelines (ADWG) Introduction

3.0 Common Water Borne Diseases

4.0 Chemicals and Substances found in Water

5.0 Pristine Water Systems Chemicals and Treatments

6.0 Water Testing/Analysis & Results

7.0 Industry Certifications

8.0 Safe Work Australia / Workplace Health & Safety / Occupational Health & Safety

9.0 Filtration & Ultraviolet Products

10.0 Types of Tanks

11.0 Other PWS Products & Equipment

12.0 Glossary of Terms

Module 3 - Appendix

Module 3 Quiz

Module 4 - Operations - Standards

1.0 Introduction

2.0 The PWS Process

3.0 Planning your Work Schedule

4.0 Planning Product Ordering

5.0 Water Testing

6.0 AqueousPro™ 50 Water Sanitiser

7.0 Water Tank Cleaning

8.0 Filtration / Sterilisation Supply (Assembly)

9.0 Ongoing Service and Maintenance

10.0 PWS Standards

11.0 AqueousAir™ Assembly & Installation Instructions

Module 4 - Appendix

Module 4 Quiz

Module 5 - Sales, Marketing, Quoting & Invoicing

1.0 Introduction

2.0 Advertising & Marketing

3.0 Selling PWS / Selling Yourself

4.0 Assessments & Quoting

5.0 Invoicing

Module 5 Appendix

Module 5 Quiz

Module 6 - Equipment Maintenance

1.0 Introduction

2.0 Vehicle Maintenance

3.0 Equipment Maintenance

Module 6 Quiz

In-Field Quick Reference Guide Content