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  • IMANAGING WASH WATER

    Best Practice Guidelines for Stormwater Pollution Prevention

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

  • 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

  • 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!

  • 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 shouldnt 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

  • 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 Councils 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 Councils wastewater system and that over-spray cannot reach the Councils 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 Councils stormwater system.

    The wash pad must be roofed to prevent rainwater from entering Councils wastewater system.

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

    CAUSING POLLUT

    ION

    COULD COST YOU

    R

    COMPANY UP TO

    $600,000!

  • 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 separators 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 Councils 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

  • 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 Councils 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 Councils 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 Councils 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 Councils Building Consents Officer for further information.

    If Councils wastewater sy