Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 


Action plan to reduce impact of the wastewater discharge


29 Wednesday November

Action plan to reduce impact of the wastewater discharge on the Manawatū River adopted

Palmerston North City Councillors at this evening’s ordinary Council meeting unanimously approved an action plan aimed at reducing the impact of the city’s wastewater discharge on the Manawatū River.

Councillors changed one recommendation to ensure Council staff reported back to the Council on a monthly basis.

Chief executive Paddy Clifford says the aim of the project is to start addressing matters related to compliance with the current resource consent as identified in the Joint River Monitoring Programme – in particular the growth of algae, bacteria and microbes (periphyton) and the impact on mayflies and other members of the macroinvertebrate community that are leading to a significant adverse effect in the River at times of low flow.

The action plan is estimated to cost $1.127million dollars this financial year and an estimated $435,000 to $635,000 in the following year.

“I’m pleased to report the plan should be able to paid from within existing budgets,” says Mr Clifford. “Staff identified offsets where staff savings have arisen and in terms of Council’s overall debt position being less than budget projection, which has led to a lower level of interest expense.”

The plan will be implemented immediately to take advantage of the summer low flow conditions in the River.

Water and waste service manager Rob Green says while the plan addresses the concerns raised in the Joint Monitoring Programme it will also help address the more general water quality matters that might be applicable in the future.

The plan comprises a mixture of further investigations, trials and specific improvements to treatment process and a consent review process. “We’ve structured it in a way to ensure all work is undertaken in a progressive and sequential way,” says Mr Green.

“Once the causes of the periphyton growth are better understood the Council will be in an improved position to make decisions about operational changes or any new facilities required.”

Rob Green says the plan is tentative in nature, especially from year two onwards, due to the uncertainty surrounding the causes of the observed effects in the River.

An allowance of $100,000 has been included in the Action Plan in year 2013/14 to initiate an investigation into best practicable option although the bulk of any expenditure including any new capital work could be expected in the term of the 2015-25 LTP.

Notes:

Proposed Action Plan
The investigations include:

What are the likely causes of higher periphyton growth. There are three aspects to this investigation:
• Why is there higher than expected Dissolved Reactive Phosphorus in the River?
• What is ‘kick starting’ periphyton growth?
• Does removing DRP at higher flows help to reduce periphyton growth?

Why is there higher than expected DRP in the River? Again several likely possibilities have been suggested for the higher than expected DRP in the River:
• Possible sorption / desorption
• Total phosphorus converting to DRP once the discharge enters the River
• Ground water contributing from leaking ponds or the landfill

What is ‘kick starting’ periphyton growth? The investigation will use bioassay techniques (inserting trays with jars containing different enhancements into the River for a period of about two weeks and measuring the growth of periphyton for each preparation).

Does removing Dissolved Reactive Phosphorus (DRP) at higher river flows help to mitigate periphyton growth? It is proposed to trial this during a significant recession period this coming summer. It is estimated that this will require dosing for approximately 22 extra days. There will also be additional sludge disposal and monitoring costs. The monitoring of the periphyton growth during this period will be integrated with Horizons regular monitoring programme.

Conduct a review of:

The effectiveness of Wastewater Treatment processes. Since the last thorough review of the wastewater treatment processes was undertaken around 1998/99 there has been growth in the city and other discharges connected to the treatment plant.

This review is to look at the loadings of the different contaminants coming into the plant and compare this with the capacity of the treatment processes to cope.

This action provides for reviewing the efficiency of the different process and will involve analysis of on line data as well looking at the aerated ponds biological processes and any other aspects that impact on treatment efficiency such as aerated pond flow circulation.


Immediate actions:
Desludging of aerated ponds. The aerated ponds are estimated to have lost about 25% of their capacity due to sludge accumulation. Biological processes in the ponds are not working as well as they should be and consequently there is a lower wastewater quality particularly with respect to BOD, suspended solids and E.coli levels as a result.

Over the past year a technique of bio-remediation has been applied to the sludge and decreased its density but not its volume. Council has since approved a plan to increase the trial period so that the contractor can increase the remediation process, at no cost to Council.

If the bio-remediation technique does prove to be successful then it will mean a large cost saving over resorting to mechanical means – as indicated this could cost up to about $700k.
In the event of it still not being successful in recovering the full lost volume in the ponds there would be savings in the cost of removing by mechanical means due to the lower density of the sludge so the total cost is not likely to be any greater.

Pilot use of clarifier at higher River flows without dosing. It is considered worthwhile to undertake a four week trial of operating the clarifier without dosing at higher River flows when the wastewater would not normally pass through the clarifier. It is not expected that this will make a very significant difference, possibly resulting in a small decrease in BOD and suspended solids. The value of trialling this would be to understand whether this facility could be used in the future in a strategic way and only a small cost is involved.

Promotion of phosphorus free detergents. Twenty per cent of DRP in the wastewater stream is estimated to come from trade waste sources and 80% from domestic sources. Of the phosphorus from domestic sources recent studies suggest that about 70-80% is from humans and about 20-30% from detergents. Promotion and advice to the community about the advantage of Phosphorus free detergents would help to make a small contribution to this issue as well as making the community aware of the source of the issue.


Assessment:
The results of the various investigations and review of treatment plant efficiency together with an understanding of any new consent standards that PNCC is likely to be required to meet will be brought together around June / July 2013.

Mitigation may require both operational changes to the current facility or if further investment is required in any new facility then a consideration of what is the best practicable option to meet the desired outcome.

Other desirable operational changes may also result from this programme of work and will be reported to the Council.

Should the assessment suggest that further treatment processes are required to reduce adverse effects to acceptable levels or meet new consent standards then further work will need to be initiated on what the best practicable option is to meet these requirements?

Consent condition 23B requires PNCC to review the best practicable option for treating and disposing of wastewater (including land disposal systems) in the 13th year of the consent, scheduled for July 2016.

To view the Action Plan please visit: http://www.pncc.govt.nz/media/1909549/agenda_council_28-11-12.pdf

Ends

© Scoop Media

 
 
 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Gordon Campbell:
On The Northland By-Election

Supposedly, Winston Peters’ victory in Northland has exposed the simmering dissatisfaction with the government that exists out in the provinces. Yet it remains to be seen whether this defeat will have much significance – and not simply because if and when Labour resumes business as usual in the Northland seat at the next election, Peters’ hold on it could simply evaporate.

On Saturday, National’s electorate vote declined by 7,000 votes, as the 9,000 majority it won last September turned into a 4,000 vote deficit – mainly because Labour supporters followed the nod and wink given by Labour leader Andrew Little, and voted tactically for Peters. In the process, Labour’s vote went down from nearly 9,000 votes six months ago, to only 1,315 on Saturday. More>>

 

PARLIAMENT TODAY:

Gordon Campbell: On A Funeral In Asia, The Northland By-Election, And News Priorities

Supposedly, New Zealand’s destiny lies in Asia, and that was one of Foreign Minister Murray McCully’s rationales for his bungled reforms at MFAT. OK. So, if that’s the case why didn’t Prime Minister John Key attend the state funeral on Sunday of Singapore’s founding leader Lee Kuan Yew? More>>

ALSO:

Werewolf Satire: Not Flag-Waving; Flag-Drowning

The panel choosing the flag options has no visual artists at all. Now, I’ve kerned the odd ligature in my time and I know my recto from my French curve so I thought I’d offer a few suggestions before they get past their depth. More>>

ALSO:

IPCA Reports: Significant Problems In Police Custody

In releasing two reports today, the Independent Police Conduct Authority has highlighted a number of significant problems with the way in which Police deal with people who are detained in Police cells. More>>

ALSO:

Inspector-General of Intelligence and Security: Inquiry Into GCSB Pacific Allegations

The complaints follow recent public allegations about GCSB activities. The complaints, and these public allegations, raise wider questions regarding the collection, retention and sharing of communications data. More>>

ALSO:

TPPA Investment Leak: "NZ Surrender To US" On Corporates Suing Governments

Professor Jane Kelsey: ‘As anticipated, the deal gives foreign investors from the TPPA countries special rights, and the power to sue the government in private offshore tribunals for massive damages if new laws, or even court decisions, significantly affected their bottom line’. More>>

ALSO:

Werewolf: The Myth Of Steven Joyce

Gordon Campbell: The myth of competence that’s been woven around Steven Joyce – the Key government’s “Minister of Everything” and “Mr Fixit” – has been disseminated from high-rises to hamlets, across the country... More>>

ALSO:

RMTU: No Public Submissions On International Government Procurement Deal

“The government is preparing to assent to the Government Procurement Agreement, a World Trade Organisation Treaty which opens up New Zealand Government contracts to foreign companies and closes the door on local businesses and their workers. However the Foreign Affairs, Defence and Trade Select Committee is refusing to take public submissions on the decision.” More>>

ALSO:

Gordon Campbell:
On Pacific Spying

So New Zealand spied on its friends and allies in the Pacific – and has not only been passing on the results to the NSA, but has apparently passed on the details of the Pacific’s relations with Taiwan to our other best friends, the Chinese. On the side, the Key government has also been using the security services to gauge the chances of Trade Minister Tim Groser landing the top job at the WTO... More>>

ALSO:

State Housing Transfer: Salvation Army Opts Out

The Salvation Army has decided against negotiating with Government for the transfer of Housing New Zealand stock.
More>>

ALSO:

Get More From Scoop

 

LATEST HEADLINES

 
 
 
 
 
 
 
 
Regional
Search Scoop  
 
 
Powered by Vodafone
NZ independent news