Trade Waste Bylaw 2002 - Schedule 1A

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SCHEDULE 1A COUNCIL’S TRADE WASTE CRITERIA

1A.1 Introduction

1A.1.1

The nature and levels of the characteristics of any wastewater discharged to the Council system shall comply with the following requirements, except where the nature and levels of such characteristics are varied by the Council as part of a Conditional Consent.

1A.1.2

The Council shall take into consideration the combined effects of wastewater discharges and may make any modifications to the following characteristics for individual discharges the Council believes are appropriate.

1A.1.3

The nature and levels of any characteristic may be varied to meet any new resource consents or other legal requirements imposed on Council – refer to 1.8 of the Bylaw.

1A.2 Physical Characteristics	Explanatory notes (not part of the Bylaw)
1A.2.2 Temperature The temperature shall not exceed 50°C.	Higher temperatures: – cause increased damage to sewer structures. – increase the potential for anaerobic conditions to form in the wastewater. – promote the release of gases such as H2S and NH3. – can adversely affect the safety of operations and maintenance personnel. A lower maximum temperature may be required for large volume discharges.
1A.2.3 Solids (a) Non-faecal gross solids shall be capable of passing through a 2 mm maximum gap size screen and any gross solids shall have a quiescent settling velocity which shall not exceed 50 mm/minute. Furthermore, grit and soil particles shall be settled out to the Council’s satisfaction.	Gross solids can cause sewer blockages.
(b) The suspended solids content of any wastewater discharged shall have a maximum concentration which shall not exceed 2000 g/m3.	High suspended solids contents can cause sewer blockages and overload the treatment processes. Where potential for such problems exists, a limit of 1000 g/m3 may be more appropriate.
(c) The settleable solids content of any wastewater shall not exceed 50 mL/l.
(d) 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 wastewater system and the treatment plant to accept such waste.	High total dissolved solids reduces effluent disposal options and may contribute to soil salinity. Where potential for such problems exists, a limit of 10,000 g/m3 may be used as a guideline.
e) Fibrous, woven, or sheet film or any other materials which may adversely interfere with the free flow of wastewater in the wastewater system or treatment plant shall not be present.
1A.2.4 Oil and grease Floatable oil, fat or grease not to exceed 30 g/m3 as determined by the MIRINZ Floatable Fat test (MIRINZ Standard Methods Publication 829 method2) Where the oil or grease is in the form of an emulsion that emulsion shall remain stable on dilution with either fresh water or seawater.
1A.2.5 Solvents and other organic liquids There shall be no free layer (whether floating or settled) of solvents or organic liquids. Refer Schedule 2B.3.2.5 for information on dissolved solvents and other organic liquids.	Some organic liquids are denser than water and will settle in sewers and traps.
1A.2.6 Emulsions of paint, adhesive, rubber, plastic For the purposes of this sub-clause: ‘Latex emulsion’ means an emulsion containing paint, adhesive, rubber, plastic, or similar material.
‘Treatable’ in relation to emulsion wastewater, 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.
(a) Latex emulsions which are not treatable may be discharged into the sewer subject to the total suspended solids not exceeding 1000 g/m3.
(b) The Council may require pre-treatment of latex emulsions if the emulsion wastewater unreasonably interferes with the operation of the Council’s treatment plant.	Latex emulsions vary considerably in their properties and local treatment works may need additional restrictions depending on the experience of the specific treatment plant and the quantity of latex to be treated.
(c) Latex emulsions of both treatable and non treatable types, shall be discharged to the sewer only at a concentration and pH range that prevents coagulation and blockage at the mixing zone in the public sewer.	Latex emulsions will coagulate when unstable and can sometimes cause sewer blockage. Latex emulsions are stable when dilute or in the correct pH range.
1A.2.7 Radioactivity Radioactivity levels shall not exceed National Radiation Laboratory guidelines	Refer National Radiation Laboratory Code of safe practice for the use of unsealed radioactive materials NRL. C1
1A.2.8 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 (coastal permit).	Colour may cause aesthetic impairment of receiving waters, and adverse affects on some treatment processes and ultra-violet disinfection. Where potential for such problems exists, a level of colour which is rendered not noticeable after 100 dilutions may be used as a guideline. Where UV disinfection is used special conditions may apply.
1A.3 Chemical characteristics	Explanatory notes (not part of the Bylaw) In the setting of restrictions for chemical characteristics the Council must be mindful of the production of harmful or noxious wastestreams from some tests, such as chemical oxygen demand and total Kjeldahl nitrogen. The need to set such restrictions and therefore the requirement to undertake the associated testing must be determined by the Council.
1A.3.1 pH value The pH shall be between 6.0 and 11.0 at all times.	Extremes of pH: – can adversely affect biological treatment processes. – can adversely affect the safety of operations and/or maintenance personnel. – cause corrosion of sewer structures. – increase the potential for the release of toxic gases such as H 2 S and HCN. Relaxation of these limits to 5.5 and 11.0 is acceptable for low volume premises which discharge into a large flow.
1A.3.2 Organic strength
1A.3.2.1 The Biochemical Oxygen Demand (BOD) of any waste may require to be restricted where the capacity for receiving and treating BOD is limited. A BOD restriction may be related to mass limits.
1A.3.3 Maximum concentrations 1A.3.3.1 Introduction The maximum concentrations permissible for the chemical characteristics of an acceptable discharge are set out in the following tables: General chemical characteristics. Table 1A.1 Toxic pollutants – heavy metals. Table 1A.2 Toxic pollutants – organic compounds And Pesticides ........................... Table 1A.3 Where appropriate, maximum daily limits (kg/day) for mass limit permitted discharges are also given.

1A.3.3.2 General chemical characteristics for Permitted Trade Waste

Table 1A.1 General chemical characteristics
Characteristic	Maximum Concentration	Mass Limit (kg/day)
MBAS (Methylene blue active substances)	500 g/m3
Ammonia (measured as N) - Free ammonia - Ammonium salts	50 g/m3 200 g/m3
Kjeldahl nitrogen	500 g/m3
Total phosphorus (as P)	150 g/m3
Sulphate (measured as SO4)	500 g/m3 1500 g/m3 (with good mixing)
Sulphite (measured as SO2)	15 g/m3
Sulphide – as H2S on acidification	5 g/m3
Chlorine (measured as Cl2) - free chlorine - hypochlorite	3 g/m3 30 g/m3
Dissolved aluminium	300 g/m3
Dissolved iron	300 g/m3
Boron (as B)	25 g/m3
Bromine (as Br2)	5 g/m3
Fluoride (as F)	30 g/m3
Cyanide – weak acid dissociable (as CN)	5 g/m3

Mass limits are not set in this Bylaw but may be set for relevant criteria in conditional consents.

MBAS is a measure of anionic surfactants. High MBAS can:

- adversely effect the efficiency of activated sludge plants.
- Impair the aesthetics of receiving waters

High ammonia:

- may adversely effect the safety of operations and maintenance personnel.
- May significantly contribute to the nutrient load to the receiving environment.

High Kjeldahl nitrogen may significantly contribute to the nutrient load of the receiving environment. A value of 150 g/m3 should be used as a guideline for sensitive receiving waters.

High phosphorus may significantly contribute to the nutrient loading of the receiving environment. A value of 50 g/m3 should be used as a guideline for sensitive receiving waters.

Sulphate:

- may adversely affect sewer structures.
- May increase the potential for the generation of sulphides in the wastewater if the sewer is prone to
become anaerobic.

Sulphite has potential to release SO2 gas and thus adversely affect the safety of operations and maintenance personnel. It is a strong reducing agent and removes dissolved oxygen thereby increasing the potential for anaerobic to form in the wastewater.

Sulphide in wastewater may:

- cause corrosion of sewer structures, particularly the top non-wetted part of a sewer.
- generate odours in sewers which could cause public nuisance.
- release the toxic H2S gas which could adversely affect the safety of operations and maintenance personnel.

Chlorine:

- can adversely affect the safety of operations and maintenance personnel.
- Can cause corrosion of sewer structures.

Aluminium compounds, particularly in the presence of calcium salts, have the potential
to precipitate as a scale which may cause a sewer blockage.

Iron salts may precipitate and cause a sewer blockage. High concentrations of ferric iron may also present colour problems depending on local conditions.

Boron is not removed by conventional treatment. High concentrations in effluent may restrict irrigation applications. Final effluent use and limits should be taken into account.

High concentrations of bromine may adversely affect the safety of operations & maintenance personnel.

Fluoride is not removed by conventional wastewater treatment, however pre-treatment can easily and economically reduce concentrations to below 20 g/m 3 .

Cyanide may produce toxic atmospheres in the sewer and adversely affect the safety of
operations and maintenance personnel

Table 1A.2 – Toxic pollutants – Heavy metals for Permitted Trade Waste

Metal	Maximum Concentration (g/m3)
Antimony Arsenic Barium Beryllium Cadmium Chromium Cobalt Copper Lead Manganese Mercury Molybdenum Silver Nickel Selenium Thallium Tin Zinc	10 5 10 0.005 0.5 4 10 10 10 20 0.005 10 2 10 10 10 20 10
† Heavy metals shall be accepted up to the maximum concentrations given only when specifically approved. Explanatory notes (not part of the Bylaw) Heavy metals have the potential to: – impair the treatment process – impact on the receiving environment – limit the reuse of sludge and effluent. Where any of these factors are critical it is important that local acceptance limits should be developed. The concentration for chromium includes all valent forms of the element. Chromium (VI) is considered to be more toxic than chromium (III), and for a discharge where chromium (III) makes up a large proportion of the characteristic, higher concentration limits may be acceptable. Specialist advice should be sought. Mass limits are not set in this bylaw but may be set for relevant criteria in conditional consents. 1A.3.3.4 Organic Compounds
Table 1A.3 – Toxic pollutants – Organic compounds and pesticides for Permitted Trade Waste
Compound		Maximum Concentration
Formaldehyde (as HCHO)		50 g/m3
Phenolic compounds (as phenols) – excluding chlorinated phenols		50 g/m3
Chlorinated phenols		0.02 g/m3
Petroleum hydrocarbons		30 g/m3
Halogenated aliphatic compounds†		1 g/m3
Monocyclic aromatic hydrocarbons		5 g/m3
Polycyclic (or polynuclear) aromatic hydrocarbons (PAHs)		0.05 g/m3
Halogenated aromatic hydrocarbons (HAHs) Polychlorinated biphenyls (PCBs) Polybrominated byphenyls (PBBs)		0.002 g/m3
Pesticides (general)† (includes insecticides, herbicides, fungicides and excludes organo-phosphate, organo-chlorine and any pesticides not registered for use in New Zealand .		0.2 g/m3
Organophosphate pesticides*†		0.1g/m3
* Excludes pesticides not registered for use in New Zealand . † These compounds shall be accepted up to the given maximum concentration only when specifically approved.

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

Formaldehyde in the sewer atmosphere can adversely affect the safety of operations and
maintenance personnel.

Phenols may adversely affect biological treatment processes. They may not be completely removed by conventional treatment and subsequently impact on the environment.

Chlorinated phenols can adversely affect biological treatment process and may impair the quality of the receiving environment.

Petroleum hydrocarbons may adversely affect the safety of operations and maintenance personnel.

Because of their stability and chemical properties these compounds:

– may adversely affect the treatment processes.
– may impair the quality of the receiving environment.
– may adversely affect the safety of operations and maintenance personnel.

These compounds (also known as benzene series) are relatively insoluble in water, and are
normally not a problem in trade waste. They may be carcinogenic and may adversely affect
the safety of operations maintenance personnel.

Many of these substances have been demonstrated to have an adverse effect on the health of animals. Some are also persistent and are not degraded by conventional treatment processes.

Because of their stability, persistence and ability to bioaccumulate in animal tissue these compounds have been severely restricted by health and environmental regulators.

The category covers all pesticides other than those that are specifically listed below.
Pesticides:

- may adversely affect the treatment processes.
- May impair the quality of the receiving environment.
- May adversely affect the safety of operations and maintenance personnel.

Levels may be too high. Need to readdress.

Mass limits are not set in this bylaw but may be set for relevant criteria in conditional consents.

1A.3.3.5 Inhibitory Chemicals

At the choice of the Council no waste being diluted at a fixed ratio to wastewater, 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 environmental statutory requirements.

1A.4 Permitted Activity – Pre-acceptance Treatment Requirements

1A.4.1 General

All premises are required to meet the conditions in Schedule 1A of the Trade Waste Bylaw. The following is a list of industries with a guide to how the requirements of the Bylaw may be achieved. The list is not exhaustive and gives guidance only as different operations will require different processes. The responsibility of meeting the Bylaw remains with the Trade Waste Consent Holder and the owner and occupier.

The following table outlines the various treatments that may be required to satisfy the Bylaw

	Screening	Oil/Grease Removal	Grit Settlement	Heavy Metal Removal	Medical Waste	PH Control	Solvent Removal
Bakeries	X	X	X
Car Wash			X
Clothing Manufacture				X		X
Dentists	X		X	X	X
Doctors Surgeries					X
Dry Cleaners							X
Hotels & Motels	X	X	X
Laundries			X			X
Marae	X	X	X
Mechanical Workshops/Service Stations		X	X	X			X
Medical Laboratories					X	X?	X?
Mortuaries					X
Photo processors				X		X	X?
Restaurants (small medium)	X	X	X
Retail butchers and fishmongers	X	X	X
Schools, polytechnics, universities (with laboratories)	X		X	X		X
Take Away Premises	X	X	X
Wineries	X	X	X			X	X?

1A.4.2 Screening Requirements

Schedule 1A of the Bylaw requires that all wastewater is screened to a 2mm gap size. This can be accomplished in small premises by using grates over drains, basket screens etc. It is preferable to screen the larger material out prior to any further treatment processes (e.g. grease trap).

1A.4.3 Grease/Oil Removal

There are many different types of grease/oil traps. The unit will need to be sized to comply with the floating fat requirements. For a grease trap to function satisfactorily good housekeeping practices are essential. To ensure that the grease/oil trap functions satisfactorily the Trade Waste Consent Holder shall:

1. Clean the grease/oil trap regularly, (this will be at least quarterly or more frequently if the grease oil trap is filling quicker).

2. Records of cleaning the grease oil trap will be kept by the Trade Waste Consent Holder. The record shall include the date of cleaning, the person who cleaned the trap and the height of the floating layer prior to cleaning.

3. The annual charge includes one inspection per year. If on that inspection the grease/oil trap is not functioning correctly or records have not been maintained the frequency of inspection will increased. The Trade Waste Consent Holder will be charged for the increased inspections.

4. If repeated inspections indicate the Trade Waste Consent Holder is not maintaining the grease/oil trap properly the permitted discharge may be cancelled and the connection terminated.

1A.4.4 Grit Settlement

The sewers in the Wastewater System have very little fall and any heavy solids discharged may cause blockages. It is essential that grit settlement is carried out to remove heavy particles. In many cases the grit settlement may be carried out in the same chamber as the grease and oil removal.

For grit removal to be satisfactory good housekeeping practices are essential. To ensure that the grit settlement is operating satisfactorily the Trade Waste Consent Holder shall:

1. Clean the grit settlement chamber regularly, (this will be at least quarterly or more frequently if the grit level is over one quarter of the depth of the chamber).

2. Records of cleaning the grit settlement chamber shall be kept by the Trade Waste Consent Holder. The record shall include the date of cleaning, the person who cleaned the chamber, and the level of grit prior to removal.

3. The annual charge includes one inspection per year. If on that inspection the grit settlement is not functioning correctly or records have not been maintained the frequency of inspection will increased. The Trade Waste Consent Holder will be charged for the increased inspections.

4. If repeated inspections indicate the Trade Waste Consent Holder is not maintaining the grit settlement chamber properly the permitted discharge may be cancelled and the connection terminated.

1A.4.5 Heavy Metal Removal

Where heavy metal levels are in excess of the maximums specified in Table 1A.2 then treatment must occur to remove those excess heavy metals. The type of treatment will be specific to each industries. There are some specific industry which will require specific pre-treatment:

Photographic processors – silver recovery from the wastewater from the processing machines must be undertaken.

Dentist – Removal of the mercury amalgam by sedimentation. Records must be kept of quantities recovered and dates of trap cleaning.

1A.4.6 Medical Waste

All Medical Waste discharged shall follow the provisions of AS/NZS 3816:1998 Health Care Waste Management.

1A.4.7 pH Correction

If the pH of the wastewater lies outside of the range in Schedule 1A then the appropriate dosing with a neutralising agent shall be undertaken.

1A.4.8 Solvent Removal

All wastewater discharged must comply with the limits set in Schedule 1A. The solvent recovery processes will be different for different premises.