The Hippo


Oct 23, 2019








Spirogyra, a form of green algae. Courtesy NH DES Limnology Center.

Most common microbial species in NH

• Diatoms: asterionella - star shaped, tabellaria - looks like a game of Tetris
• Green algae: spirogyra looks like a strand of green hair with tiny spirals inside, staurastrum looks like a three-legged starfish from the top, but seen from the side is a thick, vertical axle with three long spokes on the top and bottom. 
• Golden-brown algae: synura - looks like a cluster of balloons, dinobryon - looks like a stack of Champagne glasses that branch out
•Cyanobacteria: anabaena looks like a coil of sausage links, microcystis looks like a flash mob of cells, aphanizomenon looks like grass clippings stuck together in clumps. Together, these three are nicknamed “Annie, Phanny and Mike” by biologists.
• Rotifer: A maggot-like creature that’s shaped like an elongated jellyfish with forceps attached to its tail for grasping food.
• Daphnia: Also known as water fleas, they are larger-bodied with an exoskeleton and segmented arms. They look somewhat like microscopic shrimp.
• Copepod: Like microscopic lobster, they have antennae and a segmented tail.

From nature to faucet
How sourcing and delivering our urban drinking water varies

By Ryan Lessard

 From lakes and ponds, rivers and wells, the sources of water for southern New Hampshire each have different treatment processes, and there are subtle differences in the ready-to-drink end results, too.

“Every water source is unique. It has its own particular challenges,” said David Miller, the deputy director of water supply at Manchester Water Works.
In Manchester, the drinking water source is Massabesic Lake. Amy Smagula, a limnologist (lake scientist) for the state Department of Environmental Services, said that like most lakes in New Hampshire, Massabesic is home to a variety of plankton. Plankton are microscopic life forms that float around without much mobility, absorb nutrients like nitrogen and phosphorus and convert energy through photosynthesis. 
“Most lakes have 10 to 15 different species at one time,” Smagula said.
The more plant-like plankton are called phytoplankton, while the creepy micro-bugs and wiggly single-celled eaters in this category are known as zooplankton. Also known as algae, the various subspecies dominate at different times during the season. In the spring, the geometrically shaped diatoms are more populous and the water is clearer. By summer, lakes enter the golden-brown algae phase, which can affect the taste and odor of the water.
“It’s a very earthy smell,” Smagula said.
Green algae, which also comes out in the summer, does not affect the flavor or smell.
Then, late in the season around August to September, you see cyanobacteria blooms, which are blue-green in color. Smagula says those blooms can smell like “like a landfill on a hot day.”
While most of the life forms are filtered out in the treatment process, some of the subtle flavor changes can still be detected in faucet water.
Smagula said most of these plankton are harmless but cyanobacteria can release harmful toxins if they are present in high enough concentrations. Those toxins do not get targeted in the water treatment process.
A tale of three cities
Several ago, Smagula said, cyanobacteria were first identified in small portions of Massabesic during intermittent bloom periods, but they are still in small enough quantities and far enough from water intake valves to pose any serious health threat. 
In Concord, the primary water source is Penacook Lake, which has very little cyanobacteria to date, according to Patricia Myers, a lab technician for the city’s treatment plant. In fact, the general microbial population may be relatively light, Myers said, since Penacook Lake gets fewer nutrients for plankton to feed on. And, because it’s a protected water body, there’s no kayaking, swimming, fishing or the like allowed.
“As of now, it is the only large body of water in the Concord area that is non-milfoil-infested,” said Marco Philippon, the head of the Concord treatment plant.
Milfoil is an invasive water plant that spreads rapidly and displaces other beneficial plant species. 
Massabesic is a mixed bag with mostly forest but some roads and developments nearby, but it’s much larger, so a lot of that runoff has a greater chance of being diluted.
Pound for pound, Manchester and Concord appear to have the same volume of algae. Smagula said that scientists measure chlorophyll in the water as an indicator of algae, and both Massabesic and Penacook had 3.45 micrograms of chlorophyll per liter in July. 
In Nashua, the drinking water is managed by Pennichuck Corporation and sourced primarily from Pennichuck Brook and 10 surrounding subwatersheds in the form of ponds and tributaries. Water is also sent from the Merrimack River into the brook during the dry months. Pennichuck’s treatment supervisor Chris Countie says their water sources require constant monitoring to keep nutrient runoff from getting out of control and sections of water are mixed and aerated to prevent conditions for unwanted cyanobacteria blooms. Smagula says rivers and streams tend to have more diatoms and green algae.
Still, Paul Susca at DES says algae management is more challenging in Nashua because the water source has more plankton food in the form of nitrogen and phosphorus.
“Pennichuck’s got probably the greatest challenges because the Pennichuck Brook watershed has so much development in it,” Susca said.
That development not only means high nutrient runoff from lawns and pavement, but a greater potential for chemical contaminants from companies and automobiles. 
Plus a reduced number of forest plants means less competition for those nutrients.
“You can think of the forest as a natural filter,” Susca said.
Still, Miller suspects the end result out of the faucet is fairly similar between the three cities. Subtle differences might be detected from an algae-related odor standpoint or with levels of minerals when backup sources kick in. In Concord, water from the Contoocook River is pulled into the lake at times and, in the event a backup source is needed, they can pull from a system of four wells. That groundwater has no algae but is relatively rich in minerals like iron and manganese that can be conveyed in flavor and can stain pipes and sinks — but Concord hasn’t used its well system for the past 20 years.
The treatment process in these city plants must begin with removing organic particles and debris through a method that may surprise some. 
Rather than relying entirely on a system of screen filters, treatment plants apply chemicals that cling to the material and weigh it down to the bottom. 
Manchester uses charged ozone for its coagulant, which Philappon says is more powerful than the polyaluminum chloride Concord uses. Nashua uses ferric chloride.
A disinfectant is applied to destroy any harmful bacteria. In Concord and Manchester, monochloramine, a form of chlorine, is used. Nashua uses chlorine. Concord was the first to switch from chlorine to monochloramine and Manchester made the switch in 2006, just a few months after upgrading its treatment plant. Monochloramine is preferable to chlorine, Philippon said, because it doesn’t impart the chlorine flavor and it leaves behind fewer harmful byproducts that come about when chlorine reacts with organic material. Countie says Nashua’s water may have a bit of a chlorine flavor but the system is able to keep the byproducts at acceptably low levels.
Finally, treatment plants must ensure iron, lead and copper don’t leach from the pipes into the water through corrosion. In Concord, rather than adding a corrosion-control chemical, plant operators maintain the outgoing water at a pH balance of about 9.2 to 9.5 because, Philippon said, that is the least corrosive pH level. Miller says Manchester’s treatment plant keeps its outgoing water at a pH of just under 8 by adding sodium carbonate, and protects pipes from corrosion by also adding phosphoric acid, which creates a protective lining inside the pipes. Nashua also uses blended phosphates to protect pipes and they keep their outgoing water at a pH level of around 7 to 7.5.
None of the cities have lead in their service pipes, though some homes might still have lead pipes or fixtures with lead in them. In fact, Concord just removed the last tiny section of lead pipe in March and Philippon keeps the 18-inch gooseneck on display as a memento in his plant. 

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