COMPARISION OF NSF ONSITE WASTEWATER TREATMENT STANDARDS AND EUROPEAN NORM STANDARDS. Sharon Steiner 1

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1 COMPARISION OF NSF ONSITE WASTEWATER TREATMENT STANDARDS AND EUROPEAN NORM STANDARDS Sharon Steiner 1 Abstract NSF/ANSI Standard 40 (CBOD 5 and TSS reduction), and NSF/ANSI Standard 245 (Nitrogen reduction) will be compared to the EN Standard. The EN is the European Testing Standard for Small Wastewater Treatment Systems for up to 50 Persons. Multiple criteria will be discussed for both Standards, including test period, O&M, sludge removal, influent and effluent characteristics, dosing volume, sampling days, stress loading, performance criteria and specific data analysis. Introduction NSF/ANSI Standard 40 was originally adopted in 1970 and NSF/ANSI 245 in The European Standard was approved in 2005 by the CEN (European Committee for Standardization). This paper will review the differences or similarities between NSF/ANSI 40 and NSF/ANSI 245 to the EN The European Standard covers testing for BOD, TSS, Nitrogen and Phosphorus. So a comparison of the European Standard to the NSF standard would require an evaluation of both NSF 40 and 245. Results The NSF/ANSI Wastewater Standards vary from the European Norm in several categories. Below is a table showing the differences between NSF/ANSI 40 and the EN TESTS NSF/ANSI 40 EN REMARKS 1. Test period 26 weeks 38 weeks EN 12 weeks longer 2. Initiation of within 3 weeks Depends on Manufacturer EN (usually> 4 weeks) sample collection 3. Operation and No service or maintenance Routine maintenance must allowed in EN Std Maintenance allowed be done with the Manufacturer s Maintenance instructions 4. Sludge removal Not allowed Allowed, when specified Sludge can be removed by the Manufacturer in EN Standard in the Operating & Maintenance Instructions. 1 Sharon Steiner, Business Unit Manager, Wastewater Treatment Unit Program, NSF International, Ann Arbor, Michigan, USA

2 5. Unauthorized Not specified No unauthorized access EN test site is access highly protected. 6. Influent BOD mg/l BOD5 or BOD7(ATU) EN does not require Characteristics (30 day average) mg/l 30 day averages or COD mg/l for BOD5 or TSS TSS mg/l TSS mg/l EN challenge can be (30 day average) higher TKN mg/l TKN mg/l EN challenge can be Higher TP not required TP 5-20 mg/l EN requires TP 7. Effluent Class 1 Varies by EU country EN requires less Characteristics CBOD5 20 design loading testing. 25 mg/l (30 day avg) values are used for the 40 mg/l (7 day avg) efficiency ratio TSS 4 values for underloading 30 mg/l (30 day avg) and 2 values for overloading 45 mg/l (7 day avg) reported only 8. Hydraulic 26 consecutive weeks 38 consecutive weeks EN has longer loading and evaluation schedules 16 week design loading, 6 weeks nominal loading followed by 7.5 weeks followed by 10 weeks The test schedules of stress loading, then of stress loading, 6 weeks are different 2.5 weeks of design of nominal loading, then loading. 10 weeks of stress loading EN has more and then 6 weeks of nominal numerous stress loading tests 9. Dosing 30 day average volume 100% daily dosing volume EN more restrictive volume dosing 100% +/-10% within a +/-5% 10. Color, odor Required 3 times within Not required NSF more restrictive foam, and 26 week test oily film test 11. Sampling Minimum of 96 data days 26 data days EN requires fewer data days. NSF more restrictive.

3 Influent and effluent Influent and effluent sampling methods 24 hour composites 24 hour composites are the same. Samples taken 5 days Samples taken weekly EN fewer data days per week during design during design loading loading 12. Stress 4 stress events, wash-day, 4 stress events, Each Standard loading working-parent, power underloading, power has different type equipment failure and breakdown, low of stress events. vacation. occupation stress and overloading EN samples collected during underloading, power breakdown and overloading, no sampling for low occupation stress. ` EN samples during stress events, NSF samples collected after stress, during system recovery period. 13. Parameters ph, TSS, BOD5/CBOD5, BOD5 or BOD7 or EN uses BOD7, NSF TKN, Ammonia-N and COD or TOC, TSS, does not. Nitrate/Nitrite-N. ph, ammonium nitrogen EN uses COD or TKN, Nitrate and TP TOC, NSF does not. EN uses ISO and EN Analytical methods. NSF uses Standard Methods. 14. Class I Criteria Specific criteria must be Not noted EN has no specific met to be classified as pass/fail criteria for Class I Class I 15. Class II Criteria Specific criteria must be Not noted EN has no specific met to be classified as pass/fail criteria for Class II Class II 16. Misc NSF sites direction for Not noted EN does not system upset, improper sampling, improper dosing,

4 16. Cont. specific data points may be excluded from the 7 & 30 effluent measurements, data exclusion rational shall be noted in the final report. NSF sites direction for Not noted EN does not catastrophic site problems, and gives choice. 1. perform maintenance and re-start 2. with no maintenance have system brought back to preexisting conditions and resume testing within 3 weeks after the site problem has been identified and corrected. Data collected during the 3 week system recovery shall be excluded from the 7 & 30 effluent measurements. NSF defines a 7 day average Not Noted EN does not shall consist of a minimum of 3 days. Data days may be transferred to proceeding or following weeks to make up the 3 day requirement. No data day shall be used more than once. NSF defines a 30 day average Not Noted EN does not shall consist of a minimum of 50% of the regularly scheduled data days per month. Data may be transferred to proceeding or following months to make up the 30 day requirement. No data day shall be used more than once. During stress loading, data shall be Not Noted collected from a minimum of 2/3 of the total scheduled data days and from at least 2 of the scheduled sampling days during any single stress loading period. EN does not

5 17. Failure sensing NSF requires testing of visual and Not Noted EN does not and signaling audible portion of the alarm panel. equipment Also must have high water alarm 18. Data plate Requires manufacture name, Not Noted EN does not and service address, model number, serial label number, rated daily capacity, and system classification. 19. Product NSF has extensive list of Not Noted EN does not literature specific requirements for Owners manual, installation, O & M, Trouble shooting, & repair manuals 20. Policies NSF has an extensive list Not Noted EN does not of specific policies relating to the initial and extended service policies, stand by parts, service and maintenance, Annual audits of manufacture and Authorized Representatives. Discussion/Conclusions There are many significant differences between the NSF/ANSI Standards and the European Norm Standard. These include the start-up period, minimum size system for testing, duration of the test, service and maintenance, minimum number of samples required, hydraulic loading schedule, daily dosing, stress events, influent strength, parameters required, alarm panel testing, product literature review and many possible testing event issues. This evaluation suggests that the NSF/ANSI and EN Standards cannot be used interchangeably nor can manufactures perform one test to meet the requirements for both Standards. Unfortunately, State and County regulations that require NSF/ANSI Standards could not substitute the EN Certification or vice versa. It has been suggested that the two Standards harmonize their requirements however this has not been done. Literature Cited NSF/ANSI Standard 40 Residential wastewater treatment systems NSF/ANSI Standard 245 Wastewater treatment systems Nitrogen reduction EN Small wastewater treatment systems for up to 50 PT Part 3: Packaged and/or site assembled domestic wastewater treatment plants.