EM Zeolite

(This page is not directly related to home composting, but its a great example of how using natural products in a creative way eliminates the use of harmful chemicals and saves money. And this natural procedure is more effective than using harmful chemicals.)

Effective Micro-organisms (EM) Zeolite Balls Benefits for Waste Water Treatment Plant (WTP)


A large university campus (about 10,000 students) in Tamil Nadu, India uses waste water treatment plants (WTPs) to treat its waste water. Originally the waste water was treated with chemicals. At that time the single WTP was producing bad smells due to anaerobic decomposition of the sewage which produces methane and other smelly gases. The treated waste water could not be used for gardening due to the chlorine and chemical content content, and due to the treatment not completely eliminating coliforms from the treated water.

It was decided to see if using EM Zeolite Balls (EZBs) in the WTP could solve the problem of bad smells and harmful chemical-chlorine usage.

Note: EM is a liquid mixture of beneficial micro-organisms (lactobacillus, yeast & photo-synthetic bacteria). EM is used for many beneficial purposes in agriculture, horticulture, food processing, waste management, etc. Zeolite is a naturally occurring microporous, alumino-silicate mineral.

Materials Needed to Make the EZBs: * EM-1 liquid.

* Zeolite powder.

* Jaggery or black molasses.

* Some large leaves like banana leaves and/or teak tree leaves.

* Rice bran.

* Buckets for mixing and holding the materials for EZB fermentation.

* Air tight plastic bags.

Procedure for Making the EZBs:

* Use the EM-1, jaggery and water to make unfermented EM-2. Unfermented EM-2 is preferred because the EM microbes will be "hungry" which will accelerate the fermentation process (more on this later). 1 liter of EM-1 and 1kg jaggery will make about 20 liters of the EM-2 mixture. 20 liters of EM-2 will make about 400 of the 100 gram EZBs (40kg total of EZBs). A liter of EM-1 is about 300 Rupees (as of 2013). Thus one bottle of EM-1 can make enough EZBs to last about 2 months for our WTP treatment site. It is not necessary to use all the EM-1 at one time. We often use less EM-1 to make smaller batches of EZBs.

Note: Using EZBs instead of liquid EM allows us to use much less EM-1 and thus it saves a lot of money.

* To make the EZBs, the unfermented EM2 liquid is mixed with zeolite and some rice bran. The rice bran helps the EZBs hold together without crumbling or falling apart. With the right mixture, one could gently squeeze an EZB without any liquid being squeezed out. A good size for the EZB is 100 gram each (about 3-4 cm in diameter). Consistency in the weight of each EZB is important; it allows you to accurately monitor how much is being used to get the desired result.

* The 100 gram EZBs are then wrapped in the leaves and placed in a plastic bag which is put into a bucket for fermentation. The bag is closed tightly and some air tight material is put over the bag to push out air. The bucket is sealed and left alone and allowed to sit for a week. Its very important for the EZBs to ferment in an airtight container and in place where its not too cold or too hot and out of direct sunlight. Room temperature is best.

Using the EZBs:

In our application, about 4 to 6 fermented EZBs a day are put into the main collection pit where sewage water gathers and goes thru initial filtration. The number of EZBs used per day depends on the average flow rate of the incoming sewage.Usually the EZBs are crumbled into small pieces before going into the collection pit. The crumbled pieces of the EZBs fall to the bottom of the sewage water and inoculate it with the EM beneficial micro-organisms. It is the steady supply of these micro-organisms that prevent bad smells and help purify the sewage water. Thus expensive and environmentally harmful chemicals and chlorine are not needed.

If liquid EM was used, it would quickly flow out of the collection pit. The EZBs provide a micro-porous matrix which holds the beneficial EM micro-organisms in place so they stay at the bottom of the collection pit without flowing away. Thus much more incoming sewage water can be inoculated with the same amount of EM-1 liquid.

NOTE: For the EZBs to be effective they must be used on fresh incoming sewage. The EZBs will not be effective if the sewage sits stagnant for a period of time before entering the WTP. Thus there should not be any type of sewage holding tank used before treating the sewage with EZBs.

How the EZBs Work:

The EM beneficial micro-organisms work to help the sewage initially ferment (not oxidize) in the early stages of the sewage treatment process. Urine and feces are food for the EM micro-organisms; they eat the sewage and each others waste. This efficiently breaks down the urine and feces so they can more easily be processed later. "Breaking down" the sewage means the EM microbes digest the waste and turn it into simpler molecular compounds that can be more easily oxidized later. The initial EM fermentation process eliminates bad smells by greatly reducing the production of methane and other smelly gases. And it helps the overall sewage process be more efficient. The EM beneficial microbes greatly reduce the number of pathogenic microbes that cause anaerobic digestion and bad smells. In later stages the sewage is oxidized, and the oxidation process is made more efficient by the initial EM fermentation and digestion.

The WTP system used chemicals before switching to the EZBs. When using chemicals the Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) were often above allowed limits; sometimes 10 times over the limit. After using the EZBs, the BOD and COD came down to below the allowed limits of 30 for BOD and 60 for COD.

Using the EZBs has eliminated coliforms from the treated water. Thus it can now be used for gardening, etc. This campus exists in an area with low rainfall, so water conservation is very important.


EZBs have been very effective in eliminating bad smells around the WTP, saving money by eliminating the need for environmentally harmful chemicals, and saved water by allowing the treated water to be used for gardening, etc.

We invite anyone who is involved with the operation of a WTP to consider using this EZB method to gain all the environmental and money saving benefits listed. Please contact us if you have any questions: emzeolite@gmail.com.

To discover more do a web search for "em for waste water treatment". You'll see many links to more studies and reports on the successes of EM technology for waste water treatment.