ESR Process (PATENTED)

Operational Performance

 

The ESR Process results in:

• High solids product with little or no odor
  

• Reduced sludge volume
  

• Microbiologically inert product
  

• Treated biosolids with reduced concentrations of
  

  volatile solids, water extractable phosphates, and

        nitrates

The table below shows a general summary of the results

from the process. Please note that all the results shown

here were provided following independent tests.

Summary of results from the ESR Process

Note:

(a) The results shown here for the feed into the ESR are for the material after de-watering, i.e. as it enters the hopper.

(b) The results of the biosolids tested from the discharge of the ESR.

Reduction in Sludge Volume

The sludge bulk density is typically increased from 770 kg/m3 to approximately 1,090 kg/m3. This increase in density occurs primarily due to the pressure in the reactor squeezing the void spaces out of the sludge mixture. The increase in the density of the material during the process reduces the total volume of the biosolid material. The volume might typically be two-thirds of the original sludge volume.

Improved Percentage Solids

The total percentage solids typically increases by about 10 percentage points e.g. from 14% to 24%,or from 20% to 30%. This increase in percentage solids is due to the addition of lime and the resulting reduction in water due to the formation of calcium hydroxide.

Volatile Solids (%)

66.3% is the typical amount of the volatile solids found in the feed results, but would be expected to be nearer 75% in raw sludge. The volatile solids typically reduces by 80%. This reduction in the volatile solids percentage is partly due to dilution from the addition of lime (~25%), but it is primarily due to the volatilization and breakdown of organic compounds in the process (~55%), which form complex calcium organo salts etc. pH - The increase in pH is due to the addition of calcium oxide which raises the pH of the biosolid to between 11 and 12. At a pH of 10.5 ammonia is released from the biosolid, which is contained within the reactor.

Faecal Coliform

The <10MPN/g/TS result is the lowest number reliably detectable. The reason for such a reduction is the containment of the ammonia within the enclosed ESR reactor.

Phosphate Reduction

Phosphate lechable from the sludge is dramatically reduced as most of the phosphate is transformed from sodium phosphate to calcium phosphate, which provides a 3 log reduction in water extractable phosphates. Tests carried out on sludge samples show that phosphate concentrations are typically 4,000 to 10,000mg/kg. In the treated material the water extractable phosphate is less than 50mg/kg.

Nitrate Reduction

Volatisation and vaporization of the ammonia compounds from the sludge reduces the total nitrate content of the material by up to 10%, but the concentration of nitrate is further diluted (~30%) by the addition of quicklime and the resultant bulking of the solids.

A Reduction in Malodors

The ESR practically eliminates the malodor normally associated with sewage sludge by managing and separating the ammonia, amines and sulphide odors generated during the process.