RE: lagoon question

From: Andy Peters

Sent: Thu Dec 28 09:39:08 2017

To: R Quigley

Cc: Dan Huff; Gerald Fisher; S Major; tmolatore

Subject: RE: lagoon question

Importance: Normal

I’ll have this answer for you within the hour.

Andy Peters

City of Molalla

Public Works Operations Supervisor

(503) 829-6855 x220

Cell: 503-793-0507

apeters@cityofmolalla.com

117 N Molalla Ave

Molalla, OR 97038

From: R Quigley [mailto:rquigley@dyerpart.com]

Sent: Thursday, December 28, 2017 9:29 AM

To: Andy Peters <apeters@cityofmolalla.com>

Cc: Dan Huff <dhuff@cityofmolalla.com>; Gerald Fisher <gfisher@cityofmolalla.com>; S Major <smajor@dyerpart.com>; tmolatore <tmolatore@dyerpart.com>

Subject: RE: lagoon question

Good morning Andy,

We have a few guys in the office looking this over to give some input. One question before we get too far into it; what are you getting for effluent BOD & TSS currently, with the lagoons at the low level? Would it be possible to get the December DMR so that we can compare these values with the lagoon levels?

Thanks,

Ryan

From: Andy Peters [mailto:apeters@cityofmolalla.com]

Sent: Tuesday, December 26, 2017 3:20 PM

To: R Quigley

Cc: Dan Huff; Gerald Fisher

Subject: lagoon question

Ryan, our plant operator is trying something this year he says he’s never done before at this facility. We would like to back up his assumptions by having you think about it and give use your opinion.

As you know, in the winter we can discharge flows equal to the inflow. But in the summer we cannot, according to our operators. So the plan is to draw down the lagoons, and keep them low all winter. Then in the summer allow them to slowly accumulate when inflow exceeds outflow going to the fields. This is what you saw the other day when you were out with me and River City: lagoon levels drawn down to the sludge level. Remember that? The photos attached were from the Saturday after our meeting (12/24). The operator had felt the lagoons were too low, and for the last 4 days has had the plant turned completely off waiting for the lagoons to recharge some.

We can’t draw them down later this spring, because once they are full they are full until the following year when we can discharge to the river.

Also as you know, we have exceedances for TSS due to lagoon algae on a regular basis, both in the winter and in the summer. The question is, given our problems with Algae, is this going to work? Or are we going to exacerbate the problem, cause algae blooms, etc? Are we losing too much time-on-treatment this winter by doing this move? Or will the treatment process continue even though there may be virtually no water cap in lagoon 1? And is this a normal or even advanced lagoon management technique?

I hope this is enough to express the question. Unfortunetly, this is the best way I can state the question based on what the operators are currently telling me. Feel free to give me a call if you have any questions.