Mangere Wastewater Treatment Plant

CEE 491 Sean Schultz Lampros Mitropoulos Scott Honjiyo Presentation Contents

 Project overview  Project use and benefits  Technical issues and innovations  Social problems and policy issues Project overview  Location: ,

 Plant was first opened in 1960  Oxidation pond system covers more than 500 hectares (app 1,236 acres)

 Began upgrade construction in May of 1998

 Opened on April 4, 2003 by Prime Minister

 Run by Watercare Services limited (Public)

 Price:  $450 Million Project Usage

 LandLandbasebase water treatment system  Upon final filtering and UV disinfection, the flow is transferred to , where the channel feeds into the 17 hectare intertidal storage basin.  Has the capacity to cater to Auckland’s growing capacity.

 Provide significant environmental benefits to Harbor

 Better quality effluent discharge Positive Impacts

 Improves the Environment  Provides bathing water quality to discharge into harbor  500 hectares of oxidations ponds and sludge lagoons returned to a natural harbor environments  13 km of coastline also improved  Biggest coastal restoration effort in New Zealand

 Odor Boundary established and upheld

 Treatment cycle reduced from 21 days to 13 hours

 Haven for thousands of migrating birds  Bird roosts built for birds resting while tide covers their feeding grounds Technical Issues and Innovations

 Transformed the old Mangere Wastewater Treatment Plant  5 year project, treatment processes have been replaced  Plant reduces the treatment cycle for wastewater from 21days  13 hours Primary Treatment

■ Fine screens: From 19mm  3mm gaps between bars Extraction of inorganic material has increased from 1 5 tonnes/day

■ Preaeration tanks

■ Primary sedimentation tanks  12 tanks (70x12m)

■ Upgraded  Strengthening, recoating the tank surfaces

■ 2 products ( Sludge & wastewater)

■ Gravity thickening Secondary Treatment ■■ New process Biological Nutrient Removal (BNR)

■■ 9 Reactor/Clarifiers (D=77m)

■■ Capacity for 200,000 people/unit

■■ Reactor  4 aerobic & 4 anoxic compartments

■■ Clarifier  2 products (Activated Sludge & wastewater) ■■ Solid waste  Dissolved air flotation (DAF) thickeners

■■ 7 Anaerobic sludge digesters (15 days)

■■ Dewatering plant (100  300 wet tonnestonnes/day)/day) ■■ Effluent from clarifier

■■ Filtration (10 massive filters) ■■ Particles > 15m (=(=1515 1010 −6−6 m)

■■ UV disinfection plant largest in the world (10,000reduction in viruses) ■■ 12 parallel channels ■■ 7776 UV lamps

■■ Discharge (300,000m 22/day) ■■Treatment plant required to be fully operational during construction

■■Local Government Act –– Statement of Corporate Intent

■■Nine separate management plans

■■Resource Management Act –– Very strict conditions such as: ■■ 16 species in New Zealand. ■■ Huge nuisance factor. ■■ Monitoring and surveys required. ■■ Use of control sprays ––SectionSection 15 of Resource Management Act ■■ “Code of Practice for the Management of Agrichemicals” ■■Final Filtering and UV Disinfection.

■■Runs along main effluent channel.

■■Water, after upgrade, is of high enough quality for shellfish and even swimming. ■■ Treaty of Waitangi Claim.

■■ Maori People. Oruarangi Creek.

BlockedBlocked in 1960’s by Auckland’s sewage system.

ByBy 2005, water once again flows to the Maori. Key Statistics Design life 30 years

Base flow to the treatment plant 9 cumecs

Excess storm flows to WTP 5 cumecs

Theoretical maximum capability of the 16.5 cumecs system

Treated wastewater discharged from plant 285,000 cubic metres per day

Capacity of intertidal storage basin (17 ha) 370,000 cubic metres

Capacity of discharge pumps 25 cubic metres per second

Process biosolidsgenerated by plant 100,000 tonnes per annum Questions?