COMPLIANCE INFO_1991-2006 - Laserfiche WebLink

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CEASE AND DESIST ORDER NO. CITY OF MANTECA AND CITY OF LATHROP SAN JOAQUIN COUNTY 5. Order No 97-115 Effluent Limitation C.5. states: "Survival of aquatic organisms in 96 hour bioassays of undiluted waste shall be no less than: Minimum for any one bioassay--------------------------------70% Median for any three or more consecutive bioassays 90%" 6. Since the adoption of Order 97-115 in June 1997 and continuing through March 1998, the City of Manteca violated the Order's effluent bioassay requirement, consistently reporting 0 % survival. However,weekly sampling results for all of April and May 1998 have since been in compliance with Order No. 97-115. 7. The City of Manteca has taken corrective action measures and since April 1998 has been able to reduce the ammonia levels in the effluent by changing treatment plant operations to partially nitrify the ammonia. The change in plant operation seemingly corrected their acute toxicity problems. In addition, the City of Manteca has investigated the use of alternative bioassay test species as allowed by the EPA testing procedures. It is unclear whether these corrective actions will be long lasting and consistent over time. The toxicity problems associated to high ammonia concentrations in their discharge may reoccur once excess treatment plant capacity is loss, due to population growth, and operation flexibility is limited or may reoccur due to difficulties in nitrifying colder wastewater in winter months. Further investigation of these two concerns, treatment operations and/or a change in test species, is necessary to determine if these corrective actions will be long lasting and consistent over time. 8. Board's staff have met with City of Manteca representatives to stress the importance of consistently meeting the permit and to work with the City in finding a solution to the problem. 9. The City of Manteca continues to diligently work on this problem, and City staff are trying within their resources to find a solution to this problem. Recent improvements in the Bioassay survival rate is indicative that the City of Manteca is proceeding in the right direction but additional studies and/or corrective measures are necessary to demonstrate an ability to maintain year round compliance. 10. On 24 July 1998, in Sacramento, California, after due notice to the Discharger and all other affected persons,the Board conducted a public hearing at which evidence was received to consider a Cease and Desist Order to establish a time schedule to achieve compliance with waste discharge requirements. 11. Issuance of this order is exempt from the provisions of the California Environmental Quality Act (Public Resources Code, Section 21000, et seq.), in accordance with Section 15321 (a)(2), Title 14, California Code of Regulations. 12. Any person adversely affected by this action of the Board may petition the State Water Resources Control Board (Sate Board)to review the action. The petition must be received by the State Board Office of the Chief Counsel,P.O. Box 100, Sacramento, California 95812-0100,within 30 days of