Wellington Trade Waste Bylaw 2004

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Schedule 3 - Characteristics of Prohibited Trade Waste

S3.1 Introduction

S3.1.1 A discharge has prohibited characteristics if it has any solid, liquid or gaseous matters or any combination or mixture of such matters which by themselves or in combination with any other matters will immediately or in the course of time:

1. interfere with the free flow of wastewater in the wastewater system
2. damage any part of the wastewater system
3. in any way, cause the quality of the effluent or residual sewage sludge and other solids from any of the Council's wastewater treatment plant to breach the conditions of a consent issued under the Resource Management Act 1991, or water right, permit or other governing legislation
4. prejudice the occupational health and safety risks faced by workers in the wastewater system
5. after treatment be toxic to fish, animals or plant life in the receiving waters
6. cause malodorous gases or substances to form which are of a nature or sufficient quantity to create a public nuisance
7. have a colour or colouring substance that causes the discharge of any wastewater treatment plant to receiving waters to be coloured.

S3.2 Definitions

In this Schedule:

'Biodegradable oils and greases' means the oil and grease content of the waste decreases by 90% or more when the wastewater is subjected to a simulated wastewater treatment process which matches the Council treatment system.

'Emulsion' means a stable mixture of two or more liquids that normally will not mix. The liquids are held together in suspension by the addition of small quantities of other substances called emulsifiers.

'Latex emulsion' means an emulsion containing paint, adhesive, rubber, plastic or similar material.

'Treatable' in respect of 'latex emulsions' means the Total Organic Carbon content of the waste decreases by 90% or more when the wastewater is subjected to a simulated wastewater treatment process which matches the Council treatment system.

S3.3 Prohibited Characteristics

S3.3.1 A discharge has a prohibited characteristic if it has any amount of:

1. harmful solids, including dry solid wastes and materials that combine with water to form a cemented mass
2. liquid, solid or gas which could be flammable or explosive in the wastes, for example solvents, fuels, calcium carbide and any other material which is capable of giving rise to fire or explosion hazards either spontaneously or in combination with wastewater
3. asbestos
4. organo-metal compounds:
   1. tin (as tributyl and other organotin compounds)
   2. chromium (as organic compounds)
5. organochlorine pesticides
6. genetic wastes, including all wastes that contain or are likely to contain genetically altered organisms, unless approved by the Council;
7. any health-care waste not identified and discharged as required by NZS 4304 or any pathological or histological wastes that have not been subject to an agreement or consent with the Council
8. radioactivity levels in excess of National Radiation Laboratory guidelines.

S3.4 Physical Characteristics

The physical nature of a discharge or of particular characteristics shall be as follows.

S3.4.1 Temperature

The temperature shall not exceed 50°C.

S3.4.2 Solids

1. Non-faecal gross solids shall have a:
   1. maximum dimension that shall not exceed 15mm
   2. quiescent settling velocity that shall not exceed 50mm/minute.
2. The suspended solids content of any wastewater shall have a maximum concentration that shall not exceed 2000g/m3. However, suspended solids levels shall normally be controlled at 600g/m3 maximum. Higher levels than 600g/m3 shall only be possible in specific situations covered by a mass-flow based conditional consent. In such a consent particular account is taken of the nature of the waste, the volume and timing of the discharge and the ability of the wastewater system to receive it. See also 4.3 of this bylaw.
3. The settleable solids content of any wastewater shall not exceed 50mL/L.
4. The total dissolved solids concentration in any wastewater shall be subject to the approval of the Council having regard to the volume of the waste to be discharged and the suitability of the drainage system and the treatment plant to accept such waste.
5. Fibrous, woven, or sheet film or any other materials which may adversely interfere with the free flow of wastewater in the drainage system or treatment plant shall not be present.

S3.4.3 Oil & Grease

This clause applies to mineral oils, fats and grease used by industry and oils, fats and grease used in food preparation where:

1. there shall be no free or floating layer
2. emulsified oil, fat or grease are within the following limits:

Usual Type of Oil, Fat or Grease		Emulsion State	Diluted with Sewage	pH Range of Sewage	Temp (°C)	Extracted Oil, Fat & Grease Content (g/m3)
i.	Mineral based	Not biodegradeable and stable at:	x10	6-10	15	100
ii.	Animal or vegetable based	Biodegradeable and stable at:	x10	4.5-10	15	500
iii.		Unstable at:	x10	4.5-10	15	100

S3.4.4 Solvents & Other Organic Liquids

There shall be no solvents or organic liquids the form of:

1. an emulsion above background sewage levels
2. a free layer (whether floating or settled).

S3.4.5 Emulsions of Paint, Adhesive, Rubber, Plastic

1. Latex emulsions which are not treatable by the Council wastewater treatment plant may be discharged into the wastewater system subject to the total suspended solids not exceeding 1000g/m3, subject also to any other limitation as set under clause S3.4.2(b).
2. The Council may require pretreatment of latex emulsions if the emulsion wastewater unreasonably interferes with the operation of the Council treatment plant.
3. Latex emulsions of both treatable and non treatable types, shall be discharged to the wastewater system only at a concentration and pH range that prevents coagulation and blockage at the mixing zone in the public sewer.

S3.4.6 Colour

No waste shall have colour or colouring substance that causes the discharge to be coloured to the extent that it impairs wastewater treatment processes or compromises the final effluent discharge consent.

S3.5 Chemical Characteristics

The chemical nature of a discharge or of particular characteristics shall be as follows.

S3.5.1 pH Value

The pH shall be between 6.0 and 10.0 at all times.

class="bolder">S3.5.2 Inhibitory Chemicals

At the choice of the Council no waste that is being diluted at a fixed ratio to wastewater, as nominated by the Council, shall inhibit the performance of the wastewater treatment process such that the Council is significantly at risk or prevented from achieving its Resource consent requirements.

S3.5.3 Organic Strength

S3.5.3.1 Biochemical Oxygen Demand (BOD₅)

The BOD₅ content of any wastewater shall have a maximum concentration that shall not exceed 2500g/m3. However, BOD₅ levels shall normally be controlled at 600g/m3 maximum. Higher levels than 600g/m3 shall only be possible in specific situations covered by a mass-flow based Conditional consent. In such a consent particular account is taken of the nature of the waste, the volume and timing of the discharge and the ability of the wastewater system to receive and convey it. See also 4.3 of this Bylaw.

S3.5.3.2 Maximum Concentrations

The maximum concentrations permissible for the chemical characteristics of an acceptable discharge are set out in the following:

• Table 1: General Chemical Characteristics
• Table 2: Toxic Pollutants - Inorganic Compounds
• Table 3: Toxic Pollutants - Organic Compounds & Pesticides

Table 1: General Chemical Characteristics

Characteristic	Measured As	Maximum Concentration (g/m3)
Anionic detergent	Methylene blue active substances	500
Ammonia free ammonia ammonium salts	N	50 200
Kjeldahl nitrogen	N	500
Total phosphorus	P	150
Sulphate	SO4 With good mixing	500 1500
Sulphite	SO2	15
Sulphide	H2S on acidification	5
Chlorine free chlorine hypochlorite	Cl2	3 30
Dissolved aluminium	Al	300
Dissolved iron	Fe	300
Boron	B	25
Bromine	Br2	5
Fluoride	F	30
Cyanide	CN weak acid dissociable	5

Table 2: Toxic Pollutants* - Inorganic Compounds

Inorganic Compound of	Maximum Total Concentration† (g/m3)
Antimony	10
Arsenic	5
Barium	10
Beryllium	0.005
Cadmium	0.5
Chromium - Total i.e. includes all valent forms	5
Cobalt	10
Copper	10
Lead	10
Manganese	20
Mercury	0.005
Molybdenum	10
Nickel	10
Selenium	10
Silver	2
Thallium	10
Tin	20
Zinc	10

* Excludes pesticides not registered for use in New Zealand.
† These compounds shall be accepted up to the given maximum concentration only when specifically approved.

Table 3: Toxic Pollutants - Organic Compounds & Pesticides

Compound	Maximum Concentration* (g/m3)
Formaldehyde measured as HCHO	50
Phenolic compounds measured as phenols, excluding chlorinated phenols	50
Chlorinated phenols	0.02
Petroleum hydrocarbons	30
Halogenated aliphatic compounds†	1
Monocyclic aromatic hydrocarbons	5
Polycyclic (or polynuclear) aromatic hydrocarbons (PAHs)	0.05
Halogenated aromatic hydrocarbons (HAHs)	0.002
Polychlorinated biphenyls (PCBs)	0.002
Polybrominated biphenyls (PBBs)	0.2
Pesticides (general)* † includes insecticides, herbicides, fungicides but excludes organophosphate (see below) and organochlorine, refer S3.3.1(e) of this Schedule	20

* Excludes pesticides not registered for use in New Zealand.
† These compounds shall be accepted up to the given maximum concentration only when specifically approved.

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