Schedule One - Acceptable Dcharge Characteristics Physical Characteristics Remarks in this column are for guidance only. 1. Flow Flows larger than these values may be (i) The 24 hour volume shall be less than 5 m³. permitted as a “conditional” tradewaste (ii) The maximum instantaneous flow rate shall be consent. les s than 2.0 l/s. 2. Temperature Higher Temperatures: The temperature shall not exceed 50 °C Cause increased damage to sewer structures. Increase the potential for anaerobic conditions to form in the wastewater. Promote the release of gases such as HS and NH3. Can adversely affect the safety of operations and maintenance personnel. A lower maximum temperature may be required for large volume discharges. 3. Solids Gross solids can cause blockages. (i) Non-faecal gross solids shall have a maximum High suspended solids contents can dimension which shall not exceed 15 mm and cause sewer blockages and overload gross solids shall have an acquiescent settling the treatment processes. Where velocity which shall not exceed 50 mm/minute. potential for such problems exists. A (ii) The suspended solids content of any wastewater limit of 1000 g/ m may be more 3 shall have a maximum concentration which shall appropriate. not exceed 2000 g/m. 3 (iii) The settleable solids content of any wastewater shall not exceed 50 ml/L. (iv) 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. (v) Fibrous, woven, or sheet film or any other materials which may adversely interfere with the free flow of wastewater in the wastewater system or tr eatment plant shall not be present 4. Oil and Grease In terms of oil and greases, (i) There shall be no free or floating layer. biodegradable refers to the bio- availability of the oil and greases and the biochemicals thereby produced, and 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 wastewater treatment system. (ii) A tradewaste with mineral oil, fat or grease unavoidably emulsified, which in the opinion of the Council, is not biodegradable shall not exceed 200 g/mas petroleum 3 ether extractable matter when the emulsion is stable at a temperature of 15°C and when the emulsion is in contact with and diluted by a factor of 10 by raw sewage throughout the range pH 6.0 to pH 10.0. Page 16