Observations on Greater Dublin Strategic Drainage Study

A major study in relation to sewage and drainage has been put to Strategic Environmental Assessment  as a result of a Green Party motion.  At this stage a scoping document has been producedfor public consultation. Our response is below.
We wish to make the following observations on the Scoping Report for the Greater Dublin Strategic Drainage Study Strategic Environmental Assessment:

The SEA criteria should include                                                                                                   
•    rough calculations of total gross and net energy demand of various options
•    rough calculations of energy recovery potential
•    rough calculations of total greenhouse gas emissions associated with various options
•    rough calculations of potential for meeting energy demands from renewable sources
•    rough calculations of capital and operating costs of various options
•    recovery of phosphates for return to agriculture
•    transport by pipeline in preference to rail and by rail in preference to trucks.

Options studied should include
•    living machines and other innovative wastewater treatment methods
•    anaerobic digestion and other energy recovery techniques, including the potential for adding other organic materials derived outside the wastewater system to maximise the efficiency of these techniques
•    measures to reduce volumes of wastewater requiring treatment
•    measures to reduce volumes of organic matter in wastewater (e.g. banning sink macerators, etc.)
•    measures to reduce concentrations of substances in wastewater (e.g. heavy metals, pesticides) which pose particular difficulties in treatment or which contaminate sludges or other treatment products limiting their usefulness
•    bye-laws to address above issues
•    other management and control measures

Note that these some of these options are not necessarily alternatives to each other or to various infrastructural options, but that they do impact on the relative pros and cons of infrastructural options and therefore need to be considered at this stage.

There are a number of elements of the draft which are not correct in particular the following claims (pp 24 and 25):

The strategy option with the lowest number of wastewater treatment plant sites will perform better against this objective, as there will be a relatively lower number of potential odour sources.


Climatic Factors
The strategy option should minimise energy consumption and thus greenhouse gas (GHG) production, which contributes to climate change.
While it is not possible to determine the actual energy demand for each strategy option, the relative amount of energy required for the each strategy option in comparison to the other strategy options, will be assessed.
There is no specific target for this objective. The strategy option with the lowest number of wastewater treatment plant sites will perform best against this objective.

These are not valid assumptions. You cannot suppose that multiple small plants automatically release more greenhouse gases; nor can you suppose the opposite. These emissions needs to be calculated/estimated.

The following is not an environmental objective as described (p.23):

Deliverability and Planning Risk
There is no explicit objective for deliverability and planning risk. Rather, the relative likely deliverability of each Strategy will be examined.
A major risk to any drainage infrastructure is the risk that it will not obtain appropriate development consent. Delays can also arise during the planning system which can delay the overall implementation of the chosen Strategy.

Even if it was an environmental objective, the following assumption (p. 26) is not correct:

There is no specific target for this objective. A key factor under this objective is the number of waste water treatment plant sites which are required under each strategy option. The greater the number of sites, the greater the planning risk and the lower the relative deliverability of the strategy option.

One could as easily say that fewer sites increase risk as the consequences of any non-delivery is much greater.

We hope this is of assistance and would be glad to elaborate further on any of the points above if that would be useful.
Is sinne, le meas,

Cllrs. David Healy, Joe Corr, Robbie Kelly
Green Party /Comhaontas Glas,
Comhairle Contae Fine Gall/Fingal County Council