Why Your Municipality Should Complete a Pretreatment Survey

As businesses, manufacturing processes, and consumer products continue to change, municipal wastewater utilities need to understand what is entering their collection systems.

A comprehensive pretreatment survey can help a municipality identify commercial and industrial dischargers that may introduce unusual wastewater characteristics, high organic loads, fats, oils and grease (FOG), disinfectants, chemicals, or other compounds that could affect treatment performance.

While researching my class, The Changing World of Pretreatment, I encountered several examples of businesses incorporating THC- and CBD-related products into food, beverages, and wellness services.

These emerging businesses illustrate why wastewater pretreatment programs need to evolve along with the communities they serve.

New Businesses Can Create New Wastewater Challenges

Businesses that prepare foods, beverages, oils, extracts, or other specialty products may generate wastewater very different from normal domestic sewage.

For wastewater utilities, the important question is not necessarily what product a business sells.

The important question is:

What materials are being discharged into the sewer system?

A municipal pretreatment survey can help answer questions such as:

Are products manufactured or prepared on-site?
What raw materials are used?
How are waste products disposed of?
What cleaning and disinfecting chemicals are used?
Are fats, oils, and grease entering the sewer?
Are concentrated organic materials being discharged?
Does the business generate high-strength wastewater?
Are there unusual chemicals or process wastes entering the collection system?

Understanding these practices allows wastewater operators to identify potential problems before they affect treatment performance.

Food Preparation and FOG Management

Food-service businesses are already important targets for pretreatment programs because they can discharge significant amounts of fats, oils, and grease.

Restaurants, food trucks, commercial kitchens, bakeries, beverage producers, and specialty-food businesses may contribute:

FOG
High BOD
High COD
Suspended solids
Cleaning chemicals
Sanitizers
Concentrated food waste

When new ingredients or manufacturing processes are introduced, wastewater characteristics may change as well.

For this reason, pretreatment surveys should focus on the actual waste stream and operating practices of the business, rather than relying only on the type of business listed on a permit or license.

Do Not Overlook Small and Home-Based Businesses

Small-scale food production and home-based commercial operations may also contribute wastewater to municipal collection systems.

Depending on local regulations and sewer-use requirements, these businesses may be less visible to wastewater operators than traditional industrial users.

Questions municipalities may want to consider include:

Is commercial food being prepared at the property?
Are oils, extracts, or concentrated ingredients being used?
How is equipment cleaned?
Where does wash water go?
How are unused products and processing residues disposed of?
Are grease-control devices required?

Identifying these activities can help utilities better understand potential sources of high-strength or unusual wastewater discharges.

Emerging Contaminants and Wastewater Treatment

THC, CBD, and other emerging consumer products raise broader questions about how new compounds may enter wastewater systems.

In many cases, the effects of these materials on municipal biological treatment may not be fully understood.

Instead of assuming that a new product is either harmless or harmful to wastewater treatment, utilities can use pretreatment surveys to document:

What compounds are present
How much waste is generated
How waste is handled
Whether concentrated materials are discharged
What cleaning products are used
Whether unusual changes in wastewater quality are occurring

This information can help operators determine whether additional monitoring or pretreatment requirements may be appropriate.

Why Pretreatment Surveys Matter

A pretreatment survey gives municipalities a clearer picture of the businesses and industries connected to their wastewater collection system.

An effective survey can help identify:

High-strength wastewater sources
Industrial dischargers
FOG generators
Potential toxic or inhibitory compounds
Emerging commercial activities
Significant changes in local wastewater characteristics

The wastewater entering a treatment plant changes as the community changes.

Regular pretreatment surveys can help wastewater utilities stay informed, protect biological treatment processes, reduce collection-system problems, and respond to new sources of wastewater before they become significant operational concerns.

Figure 2. While at a coffee shop in Washington, I was asked if I wanted CBD oil in my coffee as an alternative to milk. I am not sure, nor can I find any references as to how these products will ultimately affect your wastewater streams. Image retrieved from https://holisticnootropics.com/the-ultimate-cbd-coffee-guide/

Learning from the Past: Preparing Pretreatment Programs for Emerging Wastewater Sources

Municipal wastewater systems are constantly changing as new businesses, manufacturing processes, and consumer products enter the marketplace.

Breweries, beverage manufacturers, food processors, pet-food manufacturers, and other commercial operations can generate wastewater with significantly different characteristics than normal domestic sewage.

Many of these facilities may already be addressed through industrial pretreatment programs, sewer-use ordinances, or fats, oils, and grease (FOG) management requirements.

However, wastewater utilities should periodically review local businesses and industries to make sure their pretreatment programs reflect what is actually entering the collection system.

Regular Pretreatment Surveys Help Identify New Risks

Every new business represents a potential change in wastewater loading.

Even existing businesses may modify their processes, introduce new products, or use different cleaning chemicals over time.

Regular pretreatment surveys can help wastewater utilities identify:

New industrial or commercial dischargers
High-strength wastewater
Fats, oils, and grease
Elevated BOD or COD
Suspended solids
Cleaning and sanitizing chemicals
Potentially inhibitory compounds
Changes in manufacturing processes

The goal is not to assume that every business creates a wastewater problem. It is to understand the waste stream before it becomes an operational concern.

CBD, THC, and Cannabis-Related Wastewater

Businesses involved in growing, processing, or manufacturing products containing CBD, THC, hemp, or cannabis may generate wastewater that deserves additional attention from municipal pretreatment programs.

The wastewater characteristics can vary considerably depending on the type of operation.

Cannabis and Hemp Growing Operations

Cultivation facilities may include:

Greenhouses
Hydroponic operations
Indoor growing facilities
Agricultural fields

Potential wastewater concerns can include nutrients, fertilizers, pesticides, cleaning products, suspended solids, salts, and other agricultural inputs.

Hydroponic and greenhouse operations may also generate concentrated nutrient solutions or wash water that should be properly managed rather than automatically discharged to a municipal sewer.

Utilities should evaluate these facilities according to applicable federal, state, and local regulations and their own sewer-use requirements.

Cannabis Processing and Manufacturing Wastewater

Processing cannabis or hemp into oils, extracts, beverages, foods, and other consumer products can create additional wastewater concerns.

Depending on the manufacturing process, waste streams may contain:

Oils and waxes
High concentrations of organic material
Ethanol
Hydrocarbons
Solvents
Cleaning chemicals
Food-processing waste
Failed or discarded products
Suspended solids
Other manufacturing residuals

Not every facility will discharge these materials into the sewer, but understanding how they are stored, handled, and disposed of should be part of a thorough industrial pretreatment survey.

Look Beyond Cannabis-Related Businesses

Cannabis and CBD businesses are only one example of how quickly commercial wastewater sources can change.

Other industries that may warrant regular pretreatment review include:

Breweries
Distilleries
Wineries
Food-processing facilities
Beverage manufacturers
Car washes
Truck washes
Dairy processors
Commercial kitchens
Manufacturing facilities

Each business can produce wastewater with different concentrations of BOD, COD, TSS, FOG, nutrients, salts, chemicals, or other contaminants.

The important question for wastewater operators is:

What is entering the collection system, and can the treatment plant handle it?

Planning Pretreatment Programs for the Future

Municipalities should periodically review their pretreatment and sewer-use ordinances to make sure they address current commercial and industrial wastewater sources.

Depending on local authority and applicable regulations, ordinances may include provisions for:

Industrial discharge permits
Sampling and monitoring
High-strength waste surcharges
FOG requirements
Special assessments
Prohibited discharges
Enforcement procedures
Cost recovery for excessive pollutant loading

High-strength commercial or industrial wastewater can increase treatment expenses through additional aeration, chemical use, solids production, sludge disposal, laboratory testing, and operator time.

Establishing appropriate requirements and cost-recovery provisions before problems occur can help protect both the wastewater utility and its ratepayers.

The Wastewater Industry Must Keep Evolving

The businesses operating in a community today may look very different from those operating there ten years from now.

Pretreatment programs should evolve along with them.

Regular surveys, updated ordinances, discharge monitoring, and communication with local businesses can help wastewater utilities identify emerging challenges before they affect collection systems, biological treatment, operating costs, or permit compliance.

The most important question for wastewater operators may simply be:

What’s next?

High Stakes: Marijuana and Wastewater