Feilding WWTP BACKGROUND Located Kawakawa Road Was build in 1967 - - PowerPoint PPT Presentation

Feilding WWTP

BACKGROUND

Located Kawakawa

Road

Was build in 1967 Prior to plant’s construction, sewage was treated by means of a large septic tank

Feilding WWTP Existing Infrastructure

WWTP

 Is currently servicing a

population of around 15,530.

 Based on “Feilding

Urban” population of 14,720

 Plus Bunnythorpe of 810

Also supports a number of industries including:

 Feilding Livestock

Saleyards

 Ovation  Farmers Transport Ltd  Feilding Skin Processors  Venison Packers Ltd  Manawatu Transport Ltd

Parameter of the Sewage

Q = 7,500 m3 /d BOD5 = 3,285 kg/d COD = 9,765 kg/d TSS = 9,578 kg/d TN = 533 kg/d

1.

Coupled Aerated lagoons

• 2. Primary and Secondary sedimentation/clarification

3.

Aerobic Fixed-Growth reactors, commonly known as: Biological Trickling Filters

• 4. UV disinfection

The Feilding WWTP incorporates the following Unit Processes

The removal of carbonaceous

• rganic matter

Nitrification (oxidation of ammonia (NH4 +) to nitrate

(NO3) through

nitrite (NO2 ) as intermediate product Some denitrification ( The nitrate (NO3) produced is reduced to elementary nitrogen (N2 gas) which evaporates into atmosphere)

The basic dynamics

• f these

unit processes are for:

Background to the consent

 In 2001 a new consent to

permit discharge to the Oroua River had to be

• btained, but was not

issued until 25 September 2005

 However, to be allowed

to continue to discharge to the river, a new consent needed to be

• btained by August 2009

 Four consent

applications were notified in April 2009

 In the interim period the

plant is operating under the “old” consent (2005)

MDC received several notifications from Horizons that served as warnings of non- compliance with the 2005 consent

Exceeding SS limits Exceeding Ammoniacal Nitrogen limits Exceeding E.coli limits Diffusion of discharge at the river inadequate

Discharge of treated waste water to the Oroua River

Continued discharge of treated effluent to the river will require upgrading the existing treatment facility to enable it to:

Considerably reduce the DRP Considerably

reduce TN

Slightly reduce SIN Significantly

reduce SS Significantly reduce the E-coli concentration

INTO THE DISCHARGE

Issues found through process investigation

The treatment process has significant nonlinearities and significant load/flow variations There are a wide range of hydraulic and biological response times Too few manipulated variables and too little control authority

These issues simultaneously affect:

The microorganisms’ behaviour and population distributions Disturbing the nitrification/denitrification processes The biomass/effluent separation process becomes easily disturbed Disturbing settling

PREVENTION OF SUCH DISTURBANCES MUST BE THE MAJOR GOAL

DISTURBANCES

THE ANAEROBIC LAGOON WILL PROVIDE A BUFFER AND PRELIMINARY TREATMENT FOR SLUGS OF STRONG ORGANIC WASTES The mechanism to overcome significant load variations is the implementation of an anaerobic lagoon

Total influent of Anaerobic Lagoon (future growth) PE 120,000

Q = 10,000 m3 /d BOD5 =7,710 kg/d COD = 18,615 kg/d TSS =12,153 kg/d TN =1,033 kg/d

OPTIONS/STRATEGIES: 1)BIOLOGICAL SUSPENDED GROWTH PROCESS – ACTIVATED SLUDGE PLANT (STEADY STATE PROCESS) 2)INCORPORATION OF FIXED FILM MEDIA COMBINED WITH FLOATING FINE BUBBLE AERATION WITHIN EXISTING LAGOON SYSTEMS

The mechanism to improve BOD5 removal and nitrification/denitrification in the aerated lagoons

For a more detailed explanation, please see the poster displayed in the lunchroom

FROM THE PERSPECTIVE OF A VALUE ENGINEERING REVIEW, A PROPRIETARY TERTIARY PHOSPHORUS AND SUSPENDED SOLIDS REMOVAL SYSTEM IN THE FORM OF AN ACTIFLO PROCESS HAS BEEN IMPLEMENTED. IN GENERAL THIS PROCESS REPLACES THE SECONDARY CLARIFIER.

The mechanism to improve SS and DRP removal

EFFLUENT CONTAINING PHOSPHORUS SHOULD NOT BE DISCHARGED TO THE RIVER WITHOUT FURTHER EFFLUENT POLISHING

After secondary settling in the Actiflo system the little phosphorous that is left is primarily bound to small particles that do not settle to the bottom of this basin

Testing has found that the one on the right definitely tastes better