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Recent Projects

BPO has undertaken sampling and flow monitoring of municipal water and wastewater for several of the large New Zealand engineering consulting firms including MWH, Opus Consulting and Harrison Grierson, as well as directly for local authorities such as Waipa DC, Hamilton City Council, Thames-Coromandel DC and Matamata-Piako DC. 

Public sector projects:

  • Holiday (peak usage) surveys at Matarangi Beach.
  • Summer holiday water survey Pauanui, Whangamata and Whitianga.
  • Thames WWTP load contribution survey.
  • Waipa District Council, flow monitoring of sewers in Cambridge.
  • Waipa DC Pump station flow calibration.
  • Rodney DC, water quality survey of the Old Cement Works lake.
  • Supply & installation of stormwater flow monitoring weirs for Landcare.
  • Matamata-Piako DC water supply sampling Morrinsville.
  • Hamilton City Council humidity monitoring water treatment plant UV room. 

Private sector projects:

  • Characterisation of wastewater discharge (Food processing, dental, metal fabrication, truck wash, concrete, printers, hospitals, supermarkets and laundries).
  • Trade waste compliance monitoring for a range of industries.
  • Consent applications for Land Use, stormwater and wastewater.
  • Long-term monitoring with continuous flow measurement for various sites.
  • Characterisation of wastewater using hourly samples to identify variation in organic load to a treatment plant (from saleyard, meatworks, dairy factory, chemical plant).
  • Temperature surveys in wastewater drainage.
  • Wastewater treatment trouble shooting.
  • Process optimization, design of permanent wastewater monitoring systems (Dairy industry NZ, Australia, USA & Sth America.

Cargill, Indonesia

CGR (CH4 generating reactor)

Wastewater from Cargill's palm oil mill is fed into the CGR producing up to 14,000 m3 of biogas per day. This is sufficient to produce 1 MW of electricity and provide power to the local villages and housing compounds.

Fonterra Whey Digestion

Fonterra commissioned BPO to carry out a pilot plant to test the feasibility of anaerobic digestion for the treatment of cream cheese whey. The Anaerobic Contact process was selected as the optimal technology due to its process robustness and ability to handle waste with inherently high concentration of solids and fats. 

The trial was successful and confirmed that the anaerobic contact process is capable of treating cream cheese whey at the organic loading rate of 5.2 kg COD/m3/d. The system consistently achieved very high removal efficiency with an average removal of 95% total COD and 99% soluble COD.  The system generated on average 0.32 m3 of methane per kg of COD treated.

Offally Farms

BPO carried out a performance assessment of a poorly performing effluent treatment system at Offally Pig Farm which was creating nuisance odours.  Based on our advice changes to the configuration of the anaerobic ponds were made resulting in significant reduction of odour and improvement in treatment.

Tasmanian Cheese Factory

BVF (Bulk volume Fermenter)

Treating cheese factory wastewater in Tasmania, the treatment system produces effluent of a suitable quality to be discharged to the municipal sewer.
Comprising  the anaerobic BVF reactor, followed by a  sequencing batch reactor (SBR) for aerobic polishing and nitrogen removal, the plant consistently produces effluent with Total nitrogen less than 20mg/L and ammonia less than 2 mg/L.

Pukete Digesters

The Pukete Wastewater Treatment Plant included two mesophilic anaerobic digesters, designed for treating primary sludge only. The capacity of the facility was limited and additional capacity was required.
BPO staff designed and installed recuperative thickening along with improved mixing in the two mesophilic digesters.
The capacity of the system was increased by nearly 100% and the system is more stable and has a higher volatile solids degradation. The system is more easily operated and has sufficient capacity for approximately another 10 years, at very small capital expenditure.

Nelson Odour Mitigation

BPO was engaged by Bell Island WWTP to provide a practical odour risk assessment after a significant period of complaints. Prior to the practical review being undertaken the WWTP was looking at approximately $750,000 worth of potential  investigations, many of which were of unknown effectiveness.
BPO assessed each potential odour source assigning them a risk level and giving each a priority. Concept solutions where provided for each significant odour source.  A focus was on solutions that could be self-performed by the client.
Subsequently the WWTP management have been able to work through each mitigation measure systematically, resulting in a reduction in odour events without wasting resources.

Waikato Dairy Factory Wastewater Treatment Plant

The client’s issue

The dairy factory located in the Waikato region of New Zealand, utilised a conventional aerobic pond treatment system which lacked sufficient aeration, and parts of the treatment system were no longer functioning. The wastewater being discharged was not up to specification and the aerobic pond generated serious odour issues. The new resource consent for the plant gave incredibly tight discharge limit with some parameters such as nitrate limits even higher than drinking water standards.

The solution

BPO proposed a state-of-the-art new waste-water treatment system which utilised part of the existing infrastructure. BPO proposed the proprietary anaerobic BPO-BVF digester, which has been proven in over twenty-five dairy applications, followed by an Aerobic Membrane Ultrafiltration Reactor for biological nitrogen removal and solids removal.

The tank based BPO-BVF digests the majority of the raw wastewater chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS). It is a medium rate anaerobic technology and was deliberately chosen for its ability to handle the peaks in COD loading and Fat-Oil-Grease (FOG) concentration while being easy to operate. An energy rich biogas is produced, along with a small amount of waste biomass (sludge). The biogas is used in a boiler to generate heat for the system. The anaerobic effluent is fed into the Aerobic-Membrane Ultra Filtration reactor for biological nitrogen removal and to further reduce the BOD and TSS concentration prior to final polishing.

Within the factory, various effluent streams are separately monitored on a continuous autonomous basis. Using real-time analysis, these streams are divided into high-, low- and out-of-spec streams and automatically diverted to the Anaerobic process, Aerobic process or Calamity tank, respectively.

The results

The wastewater treatment solution provided an extremely high-quality effluent that was good enough to drink and be recycled in the plant. The treatment system is reliable and robust, proving itself to be resilient against shock hydraulic and organic loadings. By selecting BPO for this wastewater treatment project, the client ensured that environmentally sustainable milk product production can be assured well into the future.

Analytical results:

TSS                               < 3 mg/L
Total Nitrogen               < 0.5 mg/L
Total Phosphorous        <2mg/L
COD                             <2 gO2/m3
E.Coli                            <1 CFU

Porter Hire

BPO installed a water reclamation system for Porter Hire's truck cleaning facility. This consists of catch-pits, hydrocyclones and receiving tanks allowing over 50% of water to be recycled.
Reject water is sent to the trade waste system and monitored 24/7 by BPO to ensure compliance and peace of mind for both the council and Porter Hire.

BANZ Technical Guide to Farm Anaerobic Digestion

BPO literally wrote the book on farm based anaerobic digestion.
The Bioenergy Association of New Zealand (BANZ) commissioned BPO to prepare the Technical Guide for Design, Construction, Operation of Anaerobic Digestion Equipment for Farm Waste Treatment.
The guide aims to provide guidance on the technical aspects of anaerobic digestion equipment for treatment of farm waste from concept development, through design and construction to the start-up and successful operation.

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