Lagoon pumping in lagoon country

How a Kansas lagoon works, and what color tells you

The treatment crew in a lagoon is algae and bacteria. Single-cell algae make the oxygen; bacteria use it to digest the waste. That's why K-State's operating guide (MF-2290) says green water is the goal. Gray-to-black water means the lagoon has gone septic: not enough oxygen, likely odor, and very possibly too much sludge on the bottom. A lagoon that's the wrong color is telling you something a mower can't fix.

Healthy looks like this: at least 3 feet of water, no floating plants or cattails, grass on the inside slope kept to 6-8 inches, no trees within 50 feet, a tight fence with a working gate, and at least 2 feet of freeboard below the berm top.

The sludge schedule (what K-State actually says)

There's no fixed pump-every-N-years rule for lagoons, and anyone who quotes you one is improvising. The verified guidance: keep at least 18 inches of water above the sludge; start measuring depth-to-sludge near the center about 10 years in, then re-check every 3-5 years. Sludge accumulates slowly, but K-State is unambiguous about the endgame: "in time it must be removed or a new lagoon built."

That's where the pump truck comes in. A septage hauler can pull sludge loads off the lagoon bottom every few years to slow the clock. A full cleanout of a sludge-packed lagoon is a much bigger job. K-State warns the cost "could be thousands of dollars" once hauling is involved, and in Sedgwick County a cleanout has to meet the same MABCD construction standards as a new lagoon. Don't forget the inline septic tank either: the 1,000-gallon tank ahead of the lagoon fills with solids like any other tank and needs routine pumping on the normal cycle.

Trouble signs worth a phone call

• Persistent odor, or water that's turned gray or black
• Water level dropping fast (possible seepage; KDHE's guideline is under a quarter-inch a day) or climbing toward the berm top
• Cattails or rooted plants in the water: mosquito habitat, and a sign it's too shallow
• Duckweed or floating mats blocking the sunlight the algae need
• Burrow damage or erosion on the berm; a sagging fence

Some of those are maintenance you can do with a mower and a rake. The sludge, the seepage, and anything involving the berm structure are jobs for a licensed crew, and structural work needs county paperwork. When you call, say it's a lagoon, give the town or township, and mention the last time (if ever) sludge was measured.