Transcript
Page 1: Best Practice Guidelines for Stormwater Pollution ...econtent.tauranga.govt.nz/data/water/files/.../managing_wash_water... · Best Practice Guidelines for Stormwater Pollution Prevention

IMANAGING WASH WATER

Best Practice Guidelines for Stormwater Pollution Prevention

MANAGING WASH WATERWASH BAYS AND OTHER OPTIONS FOR WASHING VEHICLES, EQUIPMENT, OR HARDSTAND AREAS

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1MANAGING WASH WATER

Contents

SECTION PAGE

Introduction 2

How to manage wash water 4

1. Setting up your own purpose built wash pad 4

2. Using mobile washing operators 7

3. Using vacuum trucks for wash water collection and disposal

7

4. Using a wash bath or self contained parts washing machine

8

5. Using a certified commercial wash facility 8

Information in the book is correct at the time of publication

December 2010

REPORT POLLUTION TO TAURANGA CITY

COUNCIL PH (07) 577 7000

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2 BEST PRACTICE GUIDELINES FOR STORMWATER POLLUTION PREVENTION

INTRODUCTION

What is wash water?

Wash water is produced from the washing of sites, equipment or vehicles. It is classified as a pollutant because it almost always contains contaminants.

Contaminants in wash water might include:

phosphates

solvents

acids

oils

fuel residue

sediment

heavy metals like lead, zinc and copper.

It is illegal to discharge wash water into stormwater drains, waterways or the sea. You can be fined for causing pollution and even sent to jail for serious cases. Fines can be as high as $600,000 for companies and $300,000 for an individual.

How can wash water cause pollution?

Stormwater drains lead straight to waterways. When contaminated wash water gets into the stormwater system, it can directly affect animals and plants. Oily films can build up on surface waters which limits sunlight and oxygen. This makes it difficult for plants to get energy and for animals to breathe and find food. Chemicals and heavy metals can build up in plants, animals and also in sediments, causing long term effects for both aquatic life and for human health. Contamination of soils and groundwater can also occur.

If your day to day activity involves the washing or waterblasting of:

factory areas

workshops

outside yards

equipment

or vehicles

…then your business has the potential to pollute the environment.

You need to ensure all wash water is disposed of properly. This booklet explains the different disposal methods that are appropriate for businesses and industries.

WASHING WITH

"WATER ONLY" STILL

CAUSES POLLUTION!

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3MANAGING WASH WATER

What you need to know:

Washing your site, vehicles, equipment or parts can cause water pollution if the wash water is not managed properly.

You can be fined for causing pollution.

It is not okay to wash work trucks or equipment on the open yard with wash water entering stormwater drains.

Washing with water only will still produce contaminated wash water.

If you undertake washing of engines or engine parts you must have a dedicated facility set up for this.

It is not okay to wash down your factory or workshop floor or yard without containing the wash water.

All wash pads must have a trade waste consent from Council.

All washpads must be roofed – rainwater that enters the wastewater system contributes to overloading of the network which can cause sewer overflows to the harbour.

The polluter pays – If you are not prepared to protect the environment then you shouldn’t be in the business.

Biodegradable?

Even when chemicals and detergents are not used, the material you are washing off will still be contaminated.

Although “biodegradable” or “eco friendly” detergents are designed to break down quickly in water, the initial impact on waterways will be as harmful as with any other detergent. Biodegradable does not mean environmentally friendly!

Vehicle being washed with wash water that flows directly to the stormwater system.

Wash water containing detergent draining directly into a local stream.

"BIODEGRADABLE" OR "ECO FRIENDLY"

PRODUCTS WILL CAUSE

POLLUTION IF WASHED INTO WATERWAYS

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4 BEST PRACTICE GUIDELINES FOR STORMWATER POLLUTION PREVENTION

HOW TO MANAGE WASH WATER

There are some options for controlling wash water produced from your site.

Set up your own purpose built wash pad

Use a mobile washing operator who can collect the wash water for appropriate disposal

Call in a vacuum truck operator to collect wash water during wash down

Use a self contained washing unit that can recycle all wastewater

Take vehicles or equipment to a certified commercial wash facility (car or truck wash)

SETTING UP YOUR OWN PURPOSE BUILT WASH PAD

1.

A purpose built wash pad draining to Council’s wastewater system can be set up on your site for washing of parts, equipment or vehicles.

Minimum Requirements

A wash pad must be constructed to ensure rainwater cannot enter the Council’s wastewater system and that over-spray cannot reach the Council’s stormwater system. The wash pad must be constructed to meet the following criteria:

The wash pad must be suitably sized and/or shielded to ensure containment of all wash water. Over-spray must be prevented as it has the potential to drain to Council’s stormwater system.

The wash pad must be roofed to prevent rainwater from entering Council’s wastewater system.

The wash pad must be raised sufficiently above the finished ground level of adjoining areas to exclude rainwater runoff.

CAUSING POLLUTION

COULD COST YOUR

COMPANY UP TO

$600,000!

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5MANAGING WASH WATER

Fully roofed car wash draining to sewer via 3 stage oil and grit trap

Unroofed wash pad draining to sewer via 3 stage oil and grit trap – requires roofing

Illegal washpad draining directly to the stormwater system

3 stage oil and grit trap

A wash pad must be set up with a treatment system to treat wash water before it enters Council's wastewater system. This treatment system must meet the following criteria:

The minimum level of treatment is gravity separation. The system must be designed to produce a discharge that is substantially free of settleable and floatable material. “Substantially” equates to a minimum retention time of 30 minutes for 70% of the separator’s wet volume.

The system must include a grit trap followed by a 2 or 3 stage ‘oil and sludge’ trap. Grit traps retain grit and debris; oil traps retain oil, sludge and floatable material.

Depending on the activity and nature of any cleaning agent used, significant amounts of the oil may become “emulsified” (mixed with water) and pass through a gravity separator. To prevent excess oil from entering the wastewater system, quick-break detergents may be required which rapidly break oil emulsions.

The system must be capable of consistently complying with Council’s Trade Waste Bylaw and the discharge quality referred to above.

The system must include a Council approved specific design.

The system must have a Council approved access point for sampling.

The system must have a dedicated wash pad water meter to measure the volume of discharged wash water.

ALL WASHPADS NEED

A CONSENT FROM COUNCIL

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6 BEST PRACTICE GUIDELINES FOR STORMWATER POLLUTION PREVENTION

Application Form .doc

FORM OF APPLICATION UNDER THE TRADE WASTES BYLAW OF THE TAURANGA CITY COUNCIL

The Trade Waste Officer

Tauranga City Council

Private Bag

TAURANGA

1. I/We __________________________________ being the occupier(s) of trade

premises at ___________________________________________________________

and there carrying on the business of __________________________________ and

trading as __________________________________________________ request the

consent of the Council to the discharge of trade wastes to the Council’s sewers in

accordance with the terms of the Tauranga City Council Trade Wastes Bylaw.

Contact details are:

Company Contact Person _____________________________________________

Phone Number _____________________________________________

Postal Address _____________________________________________

2. This request relates to:

(a) An already existing discharge;

(b) To a proposed new discharge;

or (c) To a proposed change in:

(i) Volume of wastes

or (ii) Rate of discharge;

or (iii) Composition of wastes previously discharged

(strike out that which is not applicable)

3. The proposed new discharge, change in volume, rate, or composition of wastes will

commence from:

Trade Waste Consent

A trade waste consent is required to discharge wash water trade wastes from wash pads to Council’s wastewater system. The following conditions may apply as part of the trade waste consent:

Oil and grit traps must be cleaned and maintained regularly and a service contract with a reputable contractor is required. A cleaning frequency may be also specified in the consent.

The consent-holder may also be required to submit proof that the trap is being maintained. Failure to maintain traps will result in the trade waste consent being cancelled and may lead to the withdrawal of Council’s wastewater service.

Self-monitoring conditions and a monthly status report must be submitted to Council.

A trade waste service charge may apply.

Building Consent

A building consent must be granted by Council for any structural and drainage works that are required for wash pad construction. Contact Council’s Building Consents Officer for further information.

If Council’s wastewater system is not available, discharge to ground soakage or direct to natural waters may be permitted by the Bay of Plenty Regional Council subject to resource consent. Contact the Regional Council's Consents Officer for further information.

The above requirements for wash pads form the minimum acceptance standard as at November 2010. These rules are subject to change.

For Trade Waste consent application forms and confirmation of requirements contact the Trade Waste Officer, Tauranga City Council.

WASHPAD

INTERCEPTORS OR

GRIT TRAPS MUST BE

CLEANED REGULARLY

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7MANAGING WASH WATER

USING MOBILE WASHING OPERATORS

Mobile operators will come to your site, carry out necessary washing of site areas, equipment or vehicles and safely collect and appropriately dispose of all wash water.

Depending on the frequency of washing required, using a mobile operator may be cheaper and more convenient than taking your vehicles or equipment to a certified wash facility.

Before using a mobile operator you should make sure that they have been consented by Council to carry out their activity.

Please check the Yellow Pages for local operators.

2.

USING VACUUM TRUCKS FOR WASH WATER COLLECTION AND DISPOSAL

Vacuum tankers or “sucker trucks” can be used effectively to collect significant volumes of wash water during cleaning. Operators can block off stormwater sump outlets and vacuum wash water up as it enters the sump or divert wash water to a collection point, e.g. using sand bags.

Vacuum trucks are a good solution following spills or when a yard or workshop area requires water blasting. Some vacuum tankers come with their own water blasting units.

Vacuum tankers can also be used to clean out oil and grit traps.

Any wash water will be contaminated so you need to ensure tanker operators dispose of waste at a facility consented to accept it.

Please check the Yellow Pages for local waste disposal operators.

3.

Vacuuming out an oil and grit trap

Vacuum tanker – “sucker truck”

DO NOT HOSE DOWN WORKSHOPS OR

YARD AREAS UNLESS YOU COLLECT THE WASH WATER

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8 BEST PRACTICE GUIDELINES FOR STORMWATER POLLUTION PREVENTION

USING A CERTIFIED COMMERCIAL WASH FACILITY

Taking vehicles to a commercial car or truck wash is simple and there are a number of sites in Tauranga available. If you wash vehicles less than once a week this is likely to be a cost effective option.

Commercial car and truck wash facilities are required to have a trade waste consent and an approved treatment system for disposal of wash water to the wastewater system.

There are also facilities that can degrease entire engines, or other vehicle parts, which cannot be carried out at a regular car wash.

Please check the Yellow Pages for local operators.

5.

Car wash facility

Automatic Carwash

USING A WASH BATH OR SELF CONTAINED PARTS WASHING MACHINE

A wide range of vehicle parts washers are available. A wash bath may be as simple as a sink with a drain into a wastewater holding tank. Advanced machines may be self contained, fully automatic with water recycling.

Wash baths must have a holding tank big enough to hold all wash water that will be generated. Wash baths require regular collection and disposal of waste product to a facility authorised to accept this waste. Solvents and oily wastewater must not be put into Council’s wastewater network, nor should wash water be tipped down the sink.

Automatic parts washing machines may be more cost effective than using staff to clean parts manually. These machines reuse the water and the dirty sludge is held in a tank for disposal. Parts washing machines would usually require servicing and waste disposal every two to three months.

There are a range of companies who can supply these products for sale or hire - hire costs may incorporate servicing and waste disposal charges.

Please check the Yellow Pages for local suppliers and operators.

4.

Automatic parts washing machine

Wash bath

THE DRAIN IS JUST

FOR RAIN

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Marathon 53571


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