1. Central Wastewater Collection, Treatment & Disposal



The reliable collection, treatment, and disposal of wastewater is a critical public service. In central sewer systems, sewage flows from its source into an underground collection system typically consisting of pipes and pumps that convey it to a centralized wastewater treatment facility (WWTF). Failure in any part of the process can significantly harm the environment, economy, and public health. Untreated wastewater can contain harmful microplastics, pharmaceuticals, toxic chemicals, bacteria, viruses, and nutrients. All spills and releases of untreated sewage are unlawful.

Wastewater treatment and disposal is regulated by the United States Environmental Protection Agency (EPA) and the Florida Department of Environmental Protection (FDEP, F.S. 403). Minimum state standards for central wastewater treatment require the removal of solid and particulate matter (primary treatment) and disinfection (secondary treatment) before disposal. These processes do not effectively reduce nitrogen and phosphorus in effluent, which can add excess nutrients to the watershed when reused for irrigation. Advanced Wastewater Treatment (AWT) provides a third level of treatment to substantially lower nitrogen and phosphorus concentrations (Figure 1.1). Treated wastewater may still contain microplastics and pharmaceuticals.

wastewater treatment CREDIT Integration and Application Network University of Maryland Center for Environmental Science
Figure 1.1. Different levels of wastewater treatment discharge effluent of different quality and nutrient content. Source: Integration and Application Network University of Maryland Center for Environmental Science

Regulated wastewater disposal options depend on the level of treatment and may include discharge into surface waters, injection into underground wells and aquifers, release to infiltration basins and spray fields, or redistribution for non-potable uses such as irrigation. Any wastewater discharged directly into Southwest Florida water bodies and their direct tributaries must first be treated to AWT standards (Grizzle-Figg Act 1987, F.S. 403.086I). The Grizzle-Figg Act further mandates that discharge of AWT water will not itself cause negative impacts to Outstanding Florida Waters, like the bays in the Sarasota Bay Estuarine System.

Activity 1:

Inventory WWTF treatment and capacity and prioritize upgrades to advanced wastewater treatment

Upgrading secondary treatment of wastewater to advanced standards is an important and cost-effective strategy for reducing nutrient loading in surface waters. An inventory of treatment and disposal capacity of Wastewater Treatment Facilities throughout Sarasota County can help assess and prioritize the cost-benefits of investments in upgraded technology.

Activity 2:

Understand and manage nutrient loads to areas irrigated with non-advanced wastewater

Appropriate irrigation of landscapes and golf courses with treated wastewater can offset nutrient loadings to waterways from fertilizer. However, there is little awareness of this benefit, and reclaimed water is typically applied in conjunction with synthetic fertilizer, compounding nutrient pollution. Greater understanding of the nutrients in reclaimed water is needed, coupled with targeted education for homeowners, lawn care professionals and golf course managers to align irrigation and fertilizer management to reduce nutrients.

Activity 3:

Invest in infrastructure to minimize wastewater spills, emergency releases, and overflows

Spills, emergency discharges, and overflows of treated and untreated sewage cause significant harm to environmental and human health. A proactive and comprehensive approach to preventing unplanned discharges should include inspection, maintenance, replacement, and upgrades of failing sanitary sewer infrastructure.

Activity 4:

Improve FDEP public reporting of wastewater discharges

Notification and access to information about wastewater spills, emergency discharges, and overflows should be timely, standardized, and clearly conveyed so citizens and non-government organizations can evaluate short-term impacts and identify long-term chronic issues for remediation.

Activity 5:

Deliver targeted education and incentives to the public to reduce sewage spills and overflows

Disposal of inappropriate items such as baby wipes and kitchen grease down toilets and drains is a common cause of sewer blockages and overflows. Broken or leaking privately owned sewer lines are also a recurring problem, especially in older areas with aging infrastructure. Educating and incentivizing citizens to understand what can and cannot be disposed down toilets, sinks and drains, and the importance of maintaining their own lateral sewer lines, will reduce sewage spills and overflows that contribute nutrients and pathogens.