Sludge from Sewage Plant
The application to the EPA details that 80,000 tonnes per annum of sewage sludge from the adjacent Tertiary Treatment Works will be incinerated in the plant. This is contrary to all statements at the Information Days run by DCC in Ringsend. Mr Matt Twomey explicitly denied on many occasions that sewage sludge would be burnt.
The principal reference in the EIS to sewage sludge is on page 5-7 as follows:
5.5.39. In the event that land spreading of sludge will no longer be an option due to
environmental constraints, it will be possible to pump the sludge directly to the proposed WtE Facility for thermal treatment. It is intended to provide a sludge pipeline from the Ringsend Wastewater Treatment Works.[our emphasis] The sludge would be pumped from the Ringsend Wastewater Treatment Works and injected into the waste feed hoppers.
Here we find, buried deep in the EIS and in the middle of a paragraph, the most important sentence in the whole document.
The applicant is clearly requesting permission to burn sewage sludge. However, the applicant does not state the quantity of sludge which they wish to incinerate.
The EIS submitted to the Board does not address the impact of burning of sludge at all. In fact the details are only to be found in the EPA application as shown in the following extract:
Attachment A.1 Non Technical Summary on page 5 of 232:
A.1.3 Quantity and Nature of Waste
The types of wastes to be accepted at the Facility include:
- Industrial Non-Hazardous Waste
Waste will be accepted only from permitted waste hauliers. No hazardous waste will be accepted at the facility.
The proposed quantities of waste to be accepted at the proposed Facility are given in the table below.
TONNES PER ANNUM (proposed) (Note1 )
Sewage Sludge (Note 2)
Industrial Non-Hazardous Sludges
Industrial Non-Hazardous Solids
Note 1: This application is being made for Household, Commercial and Non Hazardous Industrial waste which in aggregate is not to exceed 600,000 tonnes per annum. The detailed split of the types of waste is unknown at the time of submission of this application
Note 2: In the event that land spreading of sludge will no longer be an option due to environmental constraints, it will be possible to pump the sludge directly to the proposed WtE facility for thermal treatment
Note 1 in the above extract is ambiguous on the question of total quantities to be incinerated.
Is the total 600,000 tonnes per annum of all matter?
Is the total:
600,000 tonnes of Household, Commercial and Non hazardous Industrial waste
80,000 tonnes of sewage sludge
80,000 tonnes of Industrial Non-Hazardous Sludges
making a total of 760,000 tonnes per annum?
Please seek additional information from the applicant to identify the exact quantities of each of the 5 waste types listed in their EPA application they intend to incinerate in the proposed development.
Impact of Incineration of Sludge
Table A8.3 in the EIS shows that sewage sludge is 13 times more potent than municipal waste in the release of N20 which is 310 times more potent than CO2.
One reading of the impact of incinerating 80,000 tonnes of sewage sludge is:
80,000 tonnes sludge x 13 = 1.04 million tonnes MSW equivalent
Or on another reading:
80,000 tonnes sludge x 13 x 310 = 322 million tonnes MSW equivalent
There will also be a significant reduction in the thermal efficiency of the plant if it is used to dry the wet sludges. Sewage sludge has a negative calorific value.
The applicant should be requested to supply additional information to analyse the impact of incinerating large quantities of both sewage sludge and industrial non-hazardous sludges in their proposed development.