Expression of interest - sludge removal for soil rehabilitation

25 Nov 2014, 9:20 AM

Expressions of Interest are sought for the removal of dewatered waste sludge from Te Kuiti Waste Water Treatment Plant. 

The Waitomo District Council operates a Waste Water Treatment Plant located on Te Kumi Station Road north of Te Kuiti. It is situated amongst farm land and is adjacent to the NIMT railway line.

The sludge product resulting from the treatment process is stored in a sludge pond where, over time, further natural decomposition takes place as the suspended solid part of the waste product settles out.  From time to time that settled waste product is dredged and then dewatered by way of a mechanical press and converted into a sludge “cake”.

The sludge waste has been independently tested and classified as a Class “B” sludge suitable for use as a agricultural soil enrichment/rehabilitation material. Results of the analysis testing are attached.

The moisture content of the dewatered sludge cake falls in the range of 79% and 82%. Although the sludge cake has high moisture content there is little “free water”. However any container used to transport the sludge cake on public roads will need to be water tight.

If stored in the open the sludge over time naturally dries out into a crunchy material. The sludge press process produces approximately 3 tons of waste sludge per day (8 am to 5 pm), week days, but excluding any statutory public holidays and weekends.

Due to the human waste origins of the dewatered sludge a resource consent is required for the safe removal and control of the disposal to land use. Assistance can be provided in the resource consent application process.

The sludge cake will be produced year round on weekdays, but will not  be stockpiled and  must be removed year round although not specifically on a day by day basis. 

Expressions of interest are sought for the right to remove and dispose of the sludge cake. Preference will be given to proposals that offer a reliable and sustainable  removal service over time.

Any proposal must make provision to receive and store the processed material for transportation as the dewatering process will be undertaken as a continuous basis within the days and hours described. Modifications to the existing sludge disposal facility to accommodate large capacity vessels may be considered. 

WDC staff will oversee the filling process during normal working hours.

WDC seeks proposals for the removal and disposal of the sludge at no cost to WDC. 

Alternative proposals to remove and dispose of the sludge for a fee are not excluded.

Proposals must disclose both the proposed methodology for removal and the end disposal together with all associated financial information to allow a fully informed decision.

The site will be available for inspection by prospective parties on Monday 1 December 2014 at 10.00am at the Te Kuiti Waste Water Treatment plant. 

Expressions of interest setting out in writing a proposal will close on 18 December 2014 at 4.00pm.  At Waitomo District Council offices, placed in the tender box in the foyer of the Council building.

The envelope must be clearly marked;
Expression of Interest: 
Sludge removal for soil rehabilitation
Te Kuiti 


Proposals will be evaluated individually considering;

Proposed methodology of removal

Duration of removal proposal

Consistency of removal – i.e. how often

Clear set out of where and how the sludge will be utilised

Council will assist in obtaining resource consent for disposal areas proposed but all cost will be for the account of the applicant

Council will not necessarily accept any proposal. Council decision will be final.

An appropriate agreement will be entered into with the successful party to monitor the compliance with the consent conditions.