U looks to wastewater plants to recover farmland fertilizer

Most of the phosphorus that is used to grow Minnesota’s vast corn and soybean fields finds its way to the Mississippi River. Then it travels 2,000 miles, past St. Louis and New Orleans, to the Gulf of Mexico, where it not only creates a massive dead zone that kills off ocean life, but is lost forever as a useful fertilizer.

University of Minnesota researchers believe they can help stop that loss.

They’d like to capture the phosphorus, which is spread in manure and fertilizers, before it reaches the Mississippi, keeping it out of lakes, rivers and other waters where it creates, among other problems, massive toxic algae blooms.

If they’re successful, wastewater treatment plants throughout the region would also have a new way to recycle the phosphorus they remove from stormwater and sewage sludge, making the use of fertilizers in the United States more sustainable.

“We know we’re running out of phosphorus, even if we don’t know when,” said Bo Hu, a researcher at the U and project manager. “In the meantime, we’re wasting a whole lot of it in pollution that ends up in our waterways, in the Great Lakes and in the Gulf of Mexico.”

While phosphorus is found everywhere, only a few parts of the world have it in dense enough concentrations for the element to be useful as a fertilizer.

Nearly all of the phosphorus used in fertilizer and in hog or animal feed comes from phosphate rock, most of which is found and mined in Morocco at sites built up over eons from mostly bird droppings.

Some estimates say the world’s supply of minable phosphate rock will run out in less than a century. Other estimates say it could last hundreds of years. In either case, about 75% of the phosphate rock left is believed to be in Morocco.

“So in the U.S., almost all of the phosphorus is imported from other countries,” Hu said. “It’s similar to petroleum, where one or two countries really control it.”

After fertilizers and manures are spread, Minnesota’s soils are saturated in phosphorus. While some of it is used up and stored in corn and soybean crops, the majority washes away through runoff.

Much of that runoff eventually finds its way into a wastewater treatment plant.

Hu and researchers at the U would have treatment plants separate out the phosphorus from the rest of the sewage sludge, recover it and turn it back into a fertilizer using a combination of artificial stomach-like digesters and chemical treatments.

Just one treatment plant in Minnesota, the city of St. Cloud’s, is now collecting and recycling phosphorus, using a more traditional anaerobic digestive process.

One reason there is only one treatment plant in the state working with phosphorus? The equipment to separate and recover the fertilizer is expensive, Hu said.

That makes it especially difficult for treatment plants in smaller rural areas — places with ample farm fields — to recover fertilizers, he said.

The U will test using a new, potentially cheaper method that uses bacteria that eat the phosphorus in the sludge and store it in their cells, said Jim Postiglione, lead researcher on the project.

When the bacteria die, the phosphorus dissolves in the water. The researchers will then separate solids from liquids and treat the liquids with chemicals, such as magnesium hydroxide.

Once the liquid is chemically treated, the phosphorus settles and can be easily recovered as minerals ready to be used, once again, as fertilizer.

The process could cut the time it takes to break down and separate out the phosphorus from around 30 days using a traditional anaerobic digestive process to less than one day, Postiglione said.

It would also involve much smaller facilities and could help treatment plants avoid clogs in piping systems and other common problems, he said.

“If we can make for an easier separation, we can make the process more efficient,” he said.

The U is asking for $200,000 from the state’s Environmental and Natural Resources Trust Fund to build and test the system.

Each process to recover phosphorus has its pros and cons, said Tracy Hodel, St. Cloud public service director.

“Each treatment facility has a variety of different wastes; some are treating a lot more municipal waste and others have a higher percentage of industrial waste,” she said.

But St. Cloud has proved that the potential for phosphorus recovery is great.

“We’re seeing greater than 98% recovery, so very little phosphorus is lost,” Hodel said. “There is not an unlimited supply, so to be able to recover it is a great thing.”

Greg Stanley • 612-673-4882

rn//Load jQuery library using plain JavaScriptrn(function(){rn var newscript = document.createElement(‘script’);rn newscript.type=”text/javascript”;rn newscript.async = true;rn newscript.src=”https://code.jquery.com/jquery-3.1.0.min.js”;rn (document.getElementsByTagName(‘head’)[0]||document.getElementsByTagName(‘body’)[0]).appendChild(newscript);rnvar newscript2 = document.createElement(‘script’);rn newscript2.type=”text/javascript”;rn newscript2.async = true;rn newscript2.src=”https://cdnjs.cloudflare.com/ajax/libs/js-cookie/2.1.3/js.cookie.min.js”;rn (document.getElementsByTagName(‘head’)[0]||document.getElementsByTagName(‘body’)[0]).appendChild(newscript2);rn})();rn/********TEST CODE for METER SNOW PLOW ANALYTiCS*******************/rnvar meter = {};rn$(document).ready(function(){rn // console.log(“this loads well”);rn $(‘.js-optimizely-click-goal’).click(function(){rn // console.log(this);rn meter[‘type’] = $(“input[name=”offer”]”).val();rn if(meter[‘type’] = 131){meter[‘type’] = “Premium Digital Access”;}rn else if(meter[‘type’] = 130){meter[‘type’] = “Sunday Print + Digital”;}rn else if(meter[‘type’] = 129){meter[‘type’] = “7-Day Print + Digital”;}rn else if(meter[‘type’] = 128){meter[‘type’] = “Sunday Print”;}rn meter[‘date’] = new Date().toLocaleString();rn // console.log(meter[‘type’]);rn // console.log(meter[‘date’]);rn var json_meter_cookie = JSON.stringify(meter);rn Cookies.set(‘meter_sign_up’, json_meter_cookie); rn rn });rn});rn/************************************************************************/rn // FACEBOOK TRACKING PIXEL #1rn !function(f,b,e,v,n,t,s)rn {if(f.fbq)return;n=f.fbq=function(){n.callMethod?rn n.callMethod.apply(n,arguments):n.queue.push(arguments)};rn if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version=’2.0′;rn n.queue=[];t=b.createElement(e);t.async=!0;rn t.src=v;s=b.getElementsByTagName(e)[0];rn s.parentNode.insertBefore(t,s)}(window,document,’script’,rn ‘https://connect.facebook.net/en_US/fbevents.js’);rn fbq(‘init’, ‘590074241155998’); rn fbq(‘track’, ‘ViewContent’);rn rnrn{% endblock %}”},”start”:”https://users.startribune.com/placement/1/environment/3/limit-signup-optimizely/start”},{“id”:”limit-signup”,”count”:12,”action”:”ignore”,”mute”:true,”action_config”:{“template”:”{% extends “grid” %}rnrn{% block heading_text %}Youu2019ve read your 10 free articles for this 30 day period. Sign up now for local coverage you wonu2019t find anywhere else, special sections and your favorite columnists. StarTribune puts Minnesota and the world right at your fingertips. {% endblock %}rnrn{% block last %}rn{{ parent() }}rn{# limit Krux pixel from https://www.squishlist.com/strib/customshop/328/ #}rnrnrn{% endblock %}”},”start”:”https://users.startribune.com/placement/1/environment/3/limit-signup/start”},{“id”:”meter-desktop-331″,”count”:10,”action”:”ignore”,”mute”:false,”action_config”:false,”start”:”https://users.startribune.com/placement/1/environment/3/meter-desktop-331/start”},{“id”:”PDA991499opt”,”count”:9,”action”:”ignore”,”mute”:true,”action_config”:false,”start”:”https://users.startribune.com/placement/1/environment/3/PDA991499opt/start”},{“id”:”limit”,”count”:8,”action”:”inject”,”mute”:false,”action_config”:{“template”:”rn.o-overlay,rn.o-overlay * {rn display: block;rn box-sizing: border-box;rn}rnrn.o-overlay {rn position: fixed;rn top: 0;rn left: 0;rn width: 100%;rn height: 100%;rn font-size:14px;rn background: rgba(0, 0, 0, 0.8);rn z-index: 999999;rn opacity:1;rn transition:all .01s;rn}rn.o-overlay h1 {rn font-family:popular-bold, ‘Popular’;rn font-size:28px;rn}rnrn.o-modal {rn width: 100%;rn max-height: 100vh;rn overflow: auto;rn position: absolute;rn top: 50%;rn left: 0;rn -webkit-transform: translateY(-50%);rn transform: translateY(-50%);rn}rn.o-modal-middle {rn padding:5px 5px;rn position:relative;rn background:#F6E463;rn text-align:center;rn border-top:1px solid rgb(246, 228, 99);rn -webkit-box-shadow:0px 0px 0px rgba(0,0,0,0);rn box-shadow:0px 0px 0px rgba(0,0,0,0);rn}rn.o-modal-inner {rn background: #ffffff;rn margin: 0 auto;rn width: 100%;rn max-width: 600px;rn position: relative;rn}rnrn.o-button {rn display: inline-block;rn font: bold 18px/1 Whitney, sans-serif;rn margin: 0;rn padding: 0;rn border: none;rn text-decoration: none;rn color: #fff;rn background: #00824A;rn padding: 15px 20px;rn border-radius: 4px;rn border: 2px solid rgba(0, 0, 0, 0.1);rn -webkit-transition: all .1s;rn transition: all .1s;rn cursor: pointer;rn text-shadow: 0 1px rgba(0, 0, 0, 0.2);rn}rn.o-button:hover {rn text-decoration: none;rn color: #fff;rn border-color: transparent;rn background: #00824A;rn opacity:0.9;rn}rn.o-cta {rntfont:bold 38px/1 Whitney, sans-serif;rntcolor:#00824A;rntpadding:5px 0px;rntdisplay:block;rnttext-align:center;rntoverflow:hidden;rntcursor:defaultrn}rn.o-block {rn text-align: center;rn font-family:’Whitney’,sans-serif;rn}rn.o-block img {rn width: 150px;rn height: auto;rn display: block;rn margin: 0 auto 10px;rn}rn.o-block .text-left {rn text-align:left;rn}rn.o-block.pad {rn padding: 10px;rn}rn.o-block.pad-top {rn padding-top: 30px;rn}rn.o-block.pad-right {rn padding-right: 30px;rn}rn.o-block.pad-bottom {rn padding-bottom: 30px;rn}rn.o-block.pad-left {rn padding-left: 30px;rn}rn.o-block.shadow-out {rn box-shadow: 0 0 7px 0 rgba(0, 0, 0, 0);rn}rn.o-block.shadow-in {rn box-shadow: inset 0 0 7px 0 rgba(0, 0, 0, 0);rn}rnrn.o-small {rn color: #010101;rn font: italic normal 13px/1 Whitney, sans-serif;rn margin: 10px 0;rn}rn.o-small:first-child {rn margin-top: 0;rn}rn.o-small:last-child {rn margin-bottom: 0;rn}rn.o-small.left {rn text-align: left;rn}rnrn.o-small a {rn display: inline-block;rn color: inherit;rn text-decoration: underline;rn}rn.o-small a:hover {rn color: black;rn text-decoration: underline;rn}rnrn.o-bg-green {rn background:#86cff2;rn color:#ffffff;rn}rnrn.o-info {rn display:inline-block;rn position:absolute;rn bottom:20px;rn right:20px;rn overflow:visible;rn z-index:1;rn}rn.o-info:hover {rn padding-left:2em;rn padding-top:2em;rn}rn.o-info:hover div {rn display:block;rn}rn.o-info button {rn width:1.5em;rn height:1.5em;rn border-radius:100%;rn font-weight:bold;rn line-height:1.5em;rn padding:0;rn margin:0;rn border:0;rn text-align:center;rn font-size:1em;rn tbackground:#F6E463;rn}rn.o-info div {rn background:#F5F5F5;rn position:absolute;rn right:1.5em;rn bottom:1.5em;rn box-shadow:0 0 10px rgba(0,0,0,.5);rn padding:20px;rn font-size:12px;rn line-height:1.3;rn display:none;rn width:300px;rn border-radius:7px 7px 0 7pxrn}rn.o-info div a {rn text-decoration:underline;rn color:#005776;rn}rn }rnrnrnrnrnrn rn rn rn Premium Digital Access
starting at 99u00a2 rn trn SUBSCRIBErn Already a subscriber? Log in.rn rn All Star Tribune readers without a Digital Access subscription are given a limited number of complimentary articles every 30 days. Once the article limit is reached we ask readers to purchase a subscription including Digital Access to continue reading. Digital Access is included in all multi-day paper home delivery, Sunday + Digital, and Premium Digital Access subscriptions. After the 1 month Premium Digital Access introductory period you will be charged at a rate of $14.99 per month. You can see all subscription options or login to an existing subscription herern rn ?rn rn rn rn rnrn”},”start”:”https://users.startribune.com/placement/1/environment/3/limit/start”},{“id”:”nag”,”count”:7,”action”:”lightbox”,”mute”:true,”action_config”:{“height”:null,”width”:”630px”,”redirect_on_close”:null,”template”:”{% extends “shell” %}rnrn{% block substyles %}rnrn .nag {rn padding:0;rn }rn .nag-inner {rn padding:0 20px 50px;rn }rn .nag img {rn width:auto;rn margin:0 auto;rn }rn .nag h1 {rn margin-top:-20px;rn text-transform:uppercase;rn color:#61bf1a;rn text-align:center;rn font:normal 26px/1 ‘Popular bold’, serif;rn }rn .nag h2 {rn font:bold 28px/1 ‘Benton Sans’, sans-serif;rn font-style:italic;rn text-align:center;rn }rn .nag-status {rn text-align:left;rn background:#f5f5f5 url(“{{ static_url(‘img-icon-warning.png’) }}”) 12px 10px no-repeat;rn padding:12px 35px 10px;rn margin-bottom:65px;rn }rn .nag-status p {rn display:inline-block;rn margin-bottom:0;rn font:normal 14px/1 ‘Benton Sans’, sans-serif;rn font-style:italic;rn }rn .nag-status p:first-child {rn color:#ff8200;rn font-weight:bold;rn }rn .nag-status p:last-child {rn color:#ccc;rn float:right;rn }rn .nag-status .btn-link {rn color:#61bf1a;rn }rn .nag-divider {rn border-top:1px solid #e7e7e7;rn text-align:center;rn width:100%;rn max-width:500px;rn margin:40px auto 20px;rn }rn .nag-logo {rn display:inline-block;rn background:#fff;rn padding:10px;rn margin-top:-24px;rn }rn .nag-btn {rn display:block;rn font-size:24px;rn padding:20px;rn border-radius:5px;rn margin:20px auto 0;rn }rn .log-in {rn margin:-40px auto 30px;rn max-width:400px;rn }rnrn{% endblock %}rnrn{% block page %}rn{#rnrn{{ limit – count – 1 }}rnrn{{ form.flow_form_open({nextAction: ‘firstSlide’}, null, null, ‘_top’) }}rn {{ form.btn(‘Save Now’) }}rn{{ form.flow_form_close() }}rnrnrn {{ form.get_general_error_messages([‘authenticate’]) }}rn {{ form.flow_form_open({nextAction: ‘login’}, [‘authenticate’], ‘login-form’, ‘_top’) }}rn rn {{ form.login }}rn {{ form.flow_form_close() }}rnrnrnKeep reading rnu2022 Log inrnrnrnrn#}rnrn rn

You have {{ limit – count – 1 }} articles leftrn

rn Keep readingrn u00a0u00a0u2022u00a0u00a0rn Log inrn rn rn rn rn {{ form.get_general_error_messages([‘authenticate’]) }}rn {{ form.flow_form_open({nextAction: ‘login’}, [‘authenticate’], ‘login-form’, ‘_top’) }}rn rn {{ form.login }}rn {{ form.flow_form_close() }}rn rn Save More Todayrn

Over 70% off!rn rn rn Star Tribunern rn rn

99u00a2 for first 4 weeksrn {{ form.flow_form_open({nextAction: ‘firstSlide’}, null, null, ‘_top’) }}rn {{ form.button(‘Save Now’, ‘btn nag-btn’) }}rn {{ form.flow_form_close() }}rn rnrn{% endblock %}rnrn{% block last %}rn{{ parent() }}rnrn{% endblock %}”},”start”:”https://users.startribune.com/placement/1/environment/3/nag/start”},{“id”:”x”,”count”:4,”action”:”ignore”,”mute”:true,”action_config”:false,”start”:”https://users.startribune.com/placement/1/environment/3/x/start”},{“id”:”multi-start”,”count”:3,”action”:”fly_in”,”mute”:true,”action_config”:{“location”:”bottom_left”,”slide_direction”:”bottom”,”group_id”:null,”display_delay”:”0″,”collapse_delay”:”10″,”template”:”rn.fly-in-group,rn.fly-in-group *,rn.fly-in-group *:before,rn.fly-in-group *:after {rn box-sizing:border-box;rn -moz-box-sizing:border-box;rn -webkit-box-sizing:border-box;rn box-sizing:border-box;rn -webkit-text-size-adjust:none;rn margin:0;rn padding:0;rn}rn.fly-in-group {rn position:relative;rn width:300px;rn background:#484848;rn box-shadow:0 0 10px rgba(0,0,0,.3);rn}rn.fly-in-header {rn width:300px;rn height:70px;rn}rn.fly-in-collapse {rn background:#333333 url(“https://users.startribune.com/static/flow_group/14/slide/1531/1624710778/img-nag-savemoretoday.gif”) center center no-repeat;rn width:300px;rn height:70px;rn cursor:pointer;rn}rn.fly-in-close {rn position:absolute;rn top:0;rn right:0;rn height:20px;rn width:20px;rn display:block;rn color:#FFF;rn font-size:20px;rn line-height:1;rn text-decoration:none;rn cursor:pointer;rn text-align:center;rn}rn.fly-in-close:hover {rn color:#E0E0E0;rn}rn.fly-in-body {rn text-align:center;rn}rn.fly-in-body p {rn color:white;rn font:bold 14px/1 ‘Benton Sans’, sans-serif;rn text-transform:uppercase;rn margin:30px 0 7px 0;rn text-align:center;rn font-style:italic;rn}rn.fly-in-body h2 {rn color:#fff;rn font:bold 25px/1 ‘Benton Sans’, sans-serif;rn text-align:center;rn font-style:italic;rn}rn.fly-in-body h2 span {rn color: #A4A4A4;rn text-decoration:line-through;rn}rn.fly-in-start-btn {rn color:white;rn background:#61bf1a;rn font-family:”Benton Sans”,Helvetica,Arial,sans-serif;rn font-weight:bold;rn line-height:1;rn text-decoration:none;rn text-transform:uppercase;rn border:none;rn -webkit-appearance:none;rn cursor:pointer;rn padding:15px 0 12px;rn display:block;rn margin:10px auto 30px;rn width:130px;rn border-radius:5px;rn font-size:16px;rn}rn.fly-in-footer {rn background:#333 url(“https://users.startribune.com/static/flow_group/14/slide/1533/2757847127/img-logo-st-sm-darkgrey.png”) center center no-repeat;rn height:35px;rn}rnrnrn rn rn u00d7rn rn rn

From justrn

$3.79 99u00a2 a weekrn Save nowrn rn rn”},”start”:”https://users.startribune.com/placement/1/environment/3/multi-start/start”}]};

Comments are closed.