July 2018

By Jeff Lamfers, KRWA Consultant

he purpose of this article is to review what chemicals

are effective and can legally be used in and around

lagoons. I also will review how to properly use them.

In no way am I encouraging systems and operators to use

more chemicals, regardless of whatever maintenance

problems anyone may have. In fact, in my opinion,

chemical usage around lagoons is rarely needed. But

sometimes, chemical use or treatment is the most sound,

economical and effective solution. Should other options be

looked at first? Of course. But often the only or best option

is to use an approved chemical to solve a specific problem. 

In all cases, systems should contact the Kansas

Department of Health and Environment (KDHE) to discuss

using chemicals to solve a particular problem. Such contact

should be made prior to chemical use. Equally important is

to follow all application instructions and dosage

recommendations per the label on the package or container.

Operators need to read the entire label to understand how

the chemical can and cannot be used. Operators must be

familiar with all directions, warnings and precautions found

on the label. In fact, I recommend reading the label prior to

purchasing or ordering any

chemicals. Just because the

manager at the local coop says a

particular chemical can be used

for a specific problem, still do

your own research. During the

past several months, I have found two systems using a

chemical to control duckweed that was recommended by the

local coop. I easily found the label instructions on the

Internet and neither was approved for use in water! I can’t

stress enough the need to read and following label

instructions and restrictions.

Check this publication

Before going into a detailed discussion about chemical

use, I first want to recommend a useful publication that I

refer to frequently. It is entitled Aquatic Plants and Their

Control(Publication C-667, August 2005). It is published by

the Kansas State University Extension Service and is

without cost online at www.oznet.ksu.edu. The brochure

does an excellent job of helping identify various aquatic

plants so you know the chemical you choose will provide

effective control. It also discusses options other than

chemicals such as prevention,

mechanical/physical and biological

control options. While I believe the

publication was originally published for

use on ponds, lakes, rivers, marshes and

drainage ditches, it has applicability to

sewage lagoons also.


Note in this photo how the duckweed blanket is covering

nearly 100 percent of the surface area of the cells. This

blanket forms a barrier that effectively blocks sunlight and

stops algae from producing oxygen needed by bacteria to

break down sewage. This can result in offensive odors, poor

treatment and effluent violations.

In fact, in my opinion,

chemical usage around

lagoons is rarely needed.