The Central Coast Regional Water Quality Control Board has issued a notice of violation at a wastewater treatment facility, located in South San Luis Obispo County Sanitation District, Calif., following the discovery of several "areas of vulnerability" at the plant, the regulator has announced.

The news came just months after the wastewater treatment plant was fined $1.1 million for causing a sewage spill in Oceano in December 2010, when about 674,400 gallons spilled into the plant and into an Oceano neighborhood after heavy rains. However, the sanitation district has contested the fine, claiming that the spill happened because of events beyond the district's control. During the investigation that followed the incident, the regulator found other problem areas at the facility.

The Central Coast Regional Water Quality Control Board is not the only organization to have spotted irregularities at the wastewater treatment plant. A report issued in 2012 by a federal agency also pointed out two problems at the facility. According to John Wallace, administrator of the sanitation district, some of the issues outlined in the water board's report are already being dealt with, whereas others are caused by misunderstanding between board inspectors and staff at the plant. Wallace claimed that if he had met the water board before the notice was issued, some of the misunderstandings would have been clarified.

The water board's notice referred to several aspects of the wastewater treatment plant operations that could potentially cause problems. The facility lacked alarms on key equipment and the way processed wastewater solids were stored was in breach of regulations. In addition, the water board found evidence that unqualified staff performed chlorine-handling operations when they were not supposed to do so. Inspectors also raised concerns about results they got from three of the water samples because they tested higher than normal for fecal coliform bacteria, suggesting that there were problems in the disinfection process.

South San Luis Obispo County Sanitation District will have to respond to the notice by providing a technical report by Feb. 1, 2013. If it fails to meet the deadline it could be fined between $1,000 and $10,000 per day under the California Water Code. Wallace explained that the sanitation district would comply with rules and prepare the required report on time.

Wallace will be joined by other members of the sanitation district's board in Oceano to discuss the two problem areas identified as most pressing by the report: the lack of alarms on chemical pumps and the sub-standard handling of biosolids. The plant serves about 38,000 residents in Arroyo Grande, Grover Beach and Oceano.

Meanwhile, the district's attorney, Michael Seitz, has criticized the water control board, claiming that it has recently focused on "aggressively" issuing notices instead of taking a more collaborative approach and looking into ways to resolve the problems. Unfortunately, the water board decided to confront the sanitation district rather than communicate with it, he added.