Wastewater Treatment for the Food Industry

Nutrient Control

Properly treating your water can help you confidently know that your effluent stream meets permitted levels. Correct dosing is part of proper nutrient control—a process crucial to minimizing nutrient discharge and optimizing your plant’s performance. With appropriate dosing, you’ll avoid wasting resources on overtreatment. In short, plant operators are hit with costs two ways – paying too much for dosing chemicals while still being fined for excess phosphorus.

Nitrogen Removal

What if you face unfavorable nutrient ratios and high concentrations of individual substances? These challenges can reduce the degradation efficiency of your biological wastewater treatment process. It’s important to detect issues early through continuous monitoring of critical parameters and take rapid corrective action when necessary.

Phosphorus Removal

It’s integral that you control levels of phosphorus—a chemical element that promotes organic growth—in your food plant’s wastewater.

If you fail to control phosphorus accurately, your water quality will be negatively impacted and this can lead to large fines.

The widespread practice of manually testing effluent only at set time intervals often leads to overdosing or underdosing with chemical control:

• Overdosing occurs when control continues at the same rate even when phosphorus levels are low.
• Underdosing happens when phosphorus levels spike in the interval between tests. This sends excess phosphorus into the stream before control measures can be adjusted.

Aeration

Activated sludge is one of the most widely used wastewater treatment processes available today, and dissolved oxygen is a key parameter for ensuring that the microorganisms vital to a successful process remain viable.

How does it work? Oxygen is introduced into wastewater along with microorganisms to develop a biological floc, which reduces the organic content of your wastewater.

Dissolved Air Flotation (DAF)

Often in food processing plants, a DAF is used to reduce loadings and clarify wastewater. Tiny air bubbles are released into the tank causing small particulates to float to the top where they are skimmed off.

To remove larger suspended solids, coagulant is dosed into the feed water—this helps to speed up clumping and settling. Typically, chemical is dosed to the DAF based on flow rate, but dosing based on flow ignores the solids concentration. This leads to under- and over-dosing which could waste chemicals, increase your hauling costs, and result in fines.

You can stop over treating and reduce your total costs by using real-time data to dose coagulant based on solids concentrations.

Sludge Treatment

Sludge treatment applications depend on your sludge quality and characteristics. Different types of sludges will affect sludge treatment options and, ultimately, disposal. This complexity often means that sludge management is a costly operation in your wastewater treatment.

Organics Monitoring

You know that all food sources have an organic component, and that monitoring organics in water and drain lines helps your production facility quickly and accurately measure the carbon content in your water streams. This lets you:

• Maximize production yield
• Mitigate compliance risks
• Protect capital equipment

What if your wastewater has high organic loads? In such cases your facility should use chemical treatment and physical processing to reduce load levels for either re-use or discharge into the environment.

Your efficient management of organics should involve BOD for reporting purposes. Yet since the test takes five days, you can use surrogates like COD, Total Organic Carbons (TOC), and Spectral Absorption Coefficient (SAC). These offer quicker test results and early detection of upsets or spills for reduced operational and maintenance costs.

Surrogates

COD and TOC, relatively simple lab procedures, reduce testing time to two hours.

Total Organic Carbon (TOC) is a measure of the carbon content of dissolved and undissolved organic matter present in a liquid sample. Here’s how it occurs in wastewater:

• Organic carbon and hydrocarbon materials appear due to spills, accidents, cleaning operations, leaks and component failures in the industry.
• TOC is increased in water when high organic compounds are discharged to water bodies.

Monitoring TOC on-line is recommended to provide results every seven minutes and monitor continuously.

Sampling Methods

Your analysis is only as good as your sample

Even the most exacting laboratory analysis can't compensate for improper sample collection, or for a sample that’s altered because of inappropriate transport or storage.

When determining your water quality and whether you’re complying with regulations, only correct sampling procedures will deliver accurate lab results. Not only can precise sampling improve your process and data, but it can lower costs, too. Pull samples at times relative to the rate of flow and as most relevant to your specific process.

Consider using both flow and automatic sampling in your wastewater process:

• Use flow proportional sampling for more representative data
• Use automatic sampling to collect unbiased samples. Such samples:
  • Characterize wastewater and its impact on receiving bodies
  • Comply with discharge requirements
  • Provide process control by verifying lab samples

Wastewater Treatment Regulations

Wastewater treatment regulations and permit limits vary from region to region and country to country.

Target limits generally are established by the acting authority. Wastewater plants then measure and report to demonstrate compliance with established limits. In this way, governing bodies and plants alike monitor and maintain important parameters that indicate water quality and environmental and health standards. As a result they ensure the continued health and safety of the populations being served.

Wastewater Technologies

As a growing field of expertise within the wastewater treatment industry, Water Intelligence Systems use digital technologies, advanced sensors, controllers, and algorithms to allow plant operators to increase efficiencies leading to overall cost savings in running the plant.

Claros™, the Water Intelligence System from Hach, integrates all plant data sources, including system data, device data, and manually-collected data, driving decisions to maximize efficiency and cost savings.

With Water Intelligence Systems, you can track and verify data on flow rate, water composition, dissolved-oxygen, nutrient levels and other factors more easily. Advantages include responsive treatment options, automation capabilities, data visualization and report generation.

Data-driven insights into water quality, flow rate, and other factors allow you to reduce overtreatment (chemicals as well as aeration blower run time) while knowing your plant will remain within compliance limits.

As regulations become stricter and plants need to find cost-savings, Water Intelligence Systems like Claros will become more important and widely adopted. And with Hach’s growing suite of Claros-Enabled sensors, controllers, devices, process management systems, and lab equipment, you can configure a system that fits the unique requirements of your plant.