Dr Sarath Obeysekera 

In addition  to installing air pumping into lake bottom other  methods are used worldwide 

Malaysian Method 

It is believed are referring to EM (Effective Microorganism) Mud Balls, also called Bokashi Mud Balls or Genki Balls. They are widely promoted in Malaysia, Japan, Thailand, and Singapore for cleaning polluted rivers and lakes. 

The method is broadly as follows:

• Fruit waste (banana, pineapple, papaya, etc.) is fermented.
• Rice bran (or rice flakes/bran) is used as the food source for beneficial microorganisms.
• Molasses (or another sugar source) is added to promote fermentation.
• An Effective Microorganism (EM) culture containing lactic acid bacteria, yeasts, and photosynthetic bacteria is added.
• The fermented material is mixed with clay or red earth and rolled into balls.
• The balls are cured for about 2–4 weeks before being thrown into polluted lakes or rivers. 

How do they work?

The common claim is not that the balls themselves chemically generate oxygen. Instead:

• They introduce large populations of beneficial microorganisms.
• These microbes help decompose organic sludge at the lake bottom.
• As sludge decomposition improves, foul odours and hydrogen sulphide can decrease.
• Reduced organic pollution can allow dissolved oxygen levels to recover naturally over time.
• The process may also help reduce algae if excess nutrients are lowered. 

Do they actually increase oxygen?

Indirectly, yes, but not by releasing oxygen like hydrogen peroxide.

The EM microbes:

• accelerate aerobic decomposition,
• suppress some anaerobic processes that produce H₂S,
• improve water quality,
• and thereby can lead to higher dissolved oxygen if the pollution load is reduced.

However, if a lake is heavily polluted or receives continuous sewage inflow (such as Beira Lake or parts of Diyawanna Oya), EM balls alone are unlikely to solve the problem. Scientific studies suggest they work best as part of an integrated programme including:

• stopping sewage inflows,
• aeration,
• nutrient reduction,
• sludge management,
• and, where necessary, dredging. 

Interestingly, Sri Lankan researchers have tested Bokashi (EM) balls on Beira Lake to evaluate their effect on algal blooms, showing that this concept has already been studied locally. 

Given the  experience with continuous aeration on the Cormorant A platform and  the  proposal for Beira Lake, a combined approach would likely be more effective than EM balls alone:

1. Stop sewage inflows.
2. Install solar-powered diffused aeration.
3. Apply EM/Bokashi mud balls in localized sludge zones.
4. Use floating wetlands where appropriate.
5. Dredge accumulated nutrient-rich sediments if required.

This integrated strategy is much more likely to achieve long-term improvement than relying on any single treatment.

Israeli Method 

Pilot project was done near Navan Mawatha 

The  product was most likely from the Israeli company BlueGreen Water Technologies, which has developed several internationally recognized products specifically for controlling harmful algal blooms (cyanobacteria) in lakes and reservoirs. Their technology has been demonstrated in Israel and many other countries. 

The main products are:

1. Lake Guard® Oxy
   • Active ingredient: Slow-release sodium percarbonate, which gradually releases hydrogen peroxide.
   • Specifically targets toxic blue-green algae (cyanobacteria).
   • Breaks down into water, oxygen, and sodium carbonate, leaving minimal residue.
   • Approved for drinking-water reservoirs in several jurisdictions. 
2. Lake Guard® Blue
   • A floating, slow-release algaecide designed to suppress cyanobacterial blooms.
   • The floating granules drift naturally with wind and surface currents, concentrating where the algae are most abundant. 
3. Lake Guard® Dew
   • An alum (aluminium sulfate)-based flocculant.
   • Rather than killing algae directly, it causes algal cells to aggregate into larger flocs that settle to the bottom, reducing turbidity and improving water clarity. 

Hopefully Ven Gangarama Thero

will obtain funds from well wishers  rather than pumping seawater to flush Beira Lake 

( AI helped to extract some information  ) 

Dr Sarath Obeysekera