DISINFECTION

Aerated Sewage & Pumping Systems has been trying for years to eliminate chemicals from the treatment of wastewater and the Zapper has taken a mamoth step in this direction as the following will show. Over the years many types of sanitisers have been available to the market.  A number have made a quick foray into the market place prior to passing into history.  The main types seen early in the 21st century include: Liquid Chlorine Dry Chlorine Salt Water Chlorination Bromide UV Ozone Electronic Ionisation All of the above systems work well but all systems are dependent on other factors for the system to maintain efficiency.  Anyone involved in the sewage industry will know that the successful use of chlorine is dependent on the pH. Some of the above systems require clean water to operate in and the Zapper will operate in dirty water as well as clean water. CHLORINE Aerated Sewage & Pumping Systems manufacture their own chlorinator which is cost effective as well as being economical to use. There are no moving parts and it operates efficiently with small and large flows. The down side is the use of chlorine which is corrosive and has special handling requirements. ZAPPER Aerated Sewage and Pumping Systems have recently developed a new product now known as the Zapper, which is combination of electro coagulation/ionising. The Zapper was developed in 2002 and was first put into service in 2006. Developement has seen this taken from one model to several units that can accomodate most requirements. HOW IONISERS WORK The ioniser today is a very simple device.  It basically uses two components. A power source Set of Anodes The way the system works can be summed up in one word, 'Simple'. An electric current is passed through water between a set of anodes, this results in two outcomes. The molecules of water gain a positive charge. A loss of metal ions from the anodes. We will look at the action of each of the above in turn: All living organisms have an electrical charge, bacteria have a negative charge.  When postively charged molecules of water meet the negatively charged bacteria it will result in the outer membrane of the bacteria rupturing and the subsequent death of the bacteria.  The dead bacteria will flock together and will be removed. A number of metals have been and are used in ionisers, the most common is normally an alloy of copper and silver.  We can recall that silver was used to kill bacteria and copper to kill algae.  A minute number of these copper and silver 'ions' are released into the water as the water flows over the anodes and act on the respective contaminants. A big plus for Ionisers is that the positive molecules will remain in that state until being neutralised by negatively charged bacteria.  The copper and silver ions will also remain active.  Therefore there is permanent presence of sanitation within the water. Polarity:  The current reversed from one anode to the other at several intervals, this will assist in anode life. Anodes: Come in a number of materials such as copper, copper/silver, aluminium and Titanium etc. and are used in different treatment processes. The number and type of anodes used off one power source can vary, however copper and aluminium are being used very succesfully off the one power source without any problems. We should point out these are doing two completely different jobs. The life expectancy of the anodes is around 18 months and this is dependant on the materials selected and the power used per anode. Applications: The current applications for the Zapper are quite varied which the following will show: Algae removal on ponds, dams and creeks. Disinfection Flocking The industries are also quite varied and cover sewage treatment, the food industry, airconditioning and mining to name a few. Running costs: The running costs for the Zapper are very surprising as the smallest unit is capable of doing a big job and yet it only costs around 25 cents a day to operate. The volume of water per day for the smallest unit is around 60,000 litres with flows up to 80 litres per minute. ALGAE REMOVAL The photo on the left shows the pond before the Zapper was installed at the sewage treatment plant and as you can see the photo is dated 04/04/2006. The algea covered more than 50% of the surface area of the pond. The photo on the right shows the same pond after the Zapper was installed in July 2006 and when this photo was taken on 27/10/2006 the algae had completely disappeared from the surface. This pond holds 22 megalitres of water when full and at its normal operating level it holds around 12 megalitres of water. This pond has been free of algae through the summer and autumn of 2006/2007.  Water is being delivered to the pond at 60 to 80 litres per minute from the sewage treatment plant. The daily flow is between 40,000 to 80,000 litres and the water has a single pass through the Zapper. The primary function of the Zapper is disinfection and this is an additional benefit without any furthe equipment or controls. So by using the Zapper for disinfection means the algae is controlled for free. DISINFECTION One of the main reasons for developing the Zapper was for disinfection without the use of chemicals and to be more user friendly than other systems and to be able to work in all conditions. Having studied this technology for a long time and researching the different ways of doing things the whole concept started to come into its own. The biggest problem in the early days was to get a system that was reliable and could give the results we were looking for while being as easy operate.   As we progressed we started to realise the benefits were going to be far greater than what we first thought. The cost to run the unit is minimal, the anode life is better than what we first thought at full power and the application areas are still being developed. We are looking to trial the unit in other fields and when we know the results we will pass them on. The other interesting thing is we can use a large range of materials in the anodes and we know we will be able to achieve good results in other areas.

The photo on the left shows two anode chambers used for disinfection and each chamber can house four anodes. Four anodes are being used in one housing only at this stage and the water is passing through at 60 to 80 litres per minute. The space requirements are small as you can see and the controller fits into the main control panel for the plant.

This is the system that treats the water prior to discharging into the pond shown above. We knew before installing the system on this plant that it would do the two jobs but we were not 100% sure how effective it would be in treating the algae. The photo's speak for themselves.

The photo on the right shows a completely different application. The flow through this system is from right to left and the housings are a 5 micron filter, this is followed by the Zapper and then a 1 micron filter. It is treating rain water in a fruit packing factory so that it can be used as washdown water at the end of a run.

The two anodes used in this application will probably last 5 to 8 years as they are only used when the pump is on which extends their life considerably. It also means the power consumption is so low it is not a consideration due to the short time it is on. Infact it would probably cost 25 cents every two weeks to run.