Preventing a Bloodworm Invasion

Midge fly infestations can pose considerable challenges for activated sludge systems and lagoons. Also known as Chironomids or bloodworms in their larvae stage, these insects resemble mosquitos without the blood sucking proboscis. Adult males can be distinguished from females based on their feather like antennae. After dormancy in the winter, midge flies emerge in the summer ready to lay between 100 and 3,000 eggs per female.

Though midge flies do not suck blood like mosquitos, they disrupt communities in other ways. Swarms annoy both local residents and operators by flying into unsuspecting mouths and flooding outdoor lighting. A study by Selden et al. (2013) found that wastewater operators can develop allergic reactions from midge fly exposure. Chironomids can also cause quite a startle to the public when bright red larvae make their way into drinking water systems.

When it comes to maintaining treatment systems, wastewater operators may be most concerned with the larvae stage of midge flies. Their sticky red bodies cling to suspended solids encasing them in a cocoon of decaying organic matter. Under the protection of these cocoons, they can consume considerable amounts of sludge, bacteria flocc, and nitrifying bacteria. An infestation will cause sludge clumping, rising solids, or foaming issues. In one small town a bloodworm invasion wreaked havoc on an activated sludge plant over a single weekend. The wastewater operator found sticky clumps of eggs had congested the system’s pumps while larvae had eaten away at his mixed liquor suspended solids (MLSS).

Facultative lagoons and secondary clarifiers are a favored breeding ground for these pests. Midge flies prefer to lay their eggs in still, high-nutrient water with fixed media, floating scum, or algae. Once the eggs hatch, larvae will likely sink to the bottom to feed on organic matter and sludge. The hemoglobin that gives bloodworms their red color also allows them to live in low dissolved oxygen (DO) conditions.

To avoid bloodworm infestations, operators should focus on encouraging circulation and limiting food sources. Systems can start midge fly control with mixing, limiting surface scum and algae, installing bug zappers, attracting bats and swallows, or turning off lights at night. Introducing a predatory fish can also help. Lagoon operators can encourage circulation by cutting back overgrown vegetation. Any dead spots in circulation should be addressed. When these methods don’t work, some systems will use larvicides and chemical agents as a last resort. Operators should check that the control methods they’ve selected are approved by their local regulatory authorities before use.

When summer starts make sure your treatment system is kept clean and free of obstructions to circulation. With good preventative maintenance, you can spare yourself the nightmares of a bloodworm invasion.

A Microscopic Look at the Role and Life Cycle of Daphnia in Wastewater Lagoons

Knowledge of lagoon microbiology can provide proactive insight into the present conditions of your wastewater treatment processes. Since we have already covered general wastewater microbiology in a previous featured video, this week’s blog post will highlight the specific roles of Daphnia in wastewater digestion.

Daphnia, also known as water fleas and Ceriodaphnia, are metazoan crustaceans that maintain a useful position in the wastewater digestion food chain if controlled by a limiting food source or the careful addition of hyacinths. These one-eyed crustaceans can consume yeast, algae, bacteria, protozoa and occasionally sludge during the winter. In the wild Daphnia are a food source for small fish, tad poles, and aquatic insects. General stressors for water fleas include cold temperatures, overcrowding, low dissolved oxygen (DO), high ammonia levels, and high pH.

To provide context for Daphnia's role in lagoon treatment requires a review of the wastewater food chain. Bacteria are at the heart of waste digestion breaking down organic material into settleable particles. Protozoa feed on these bacteria populations reducing the organic load. Metazoan organisms like Daphnia keep the populations of protozoa, bacteria, and algae in check.

Daphnia can be useful to wastewater operators under healthy lagoon conditions. These water fleas control green algae populations in the summer. As long as cyanobacteria weren't competing with those algae populations, overall pond health will improve by a reduction in total suspended solids (TSS), cloudiness, and turbidity. At the cost of growing Daphnia populations, dissolved oxygen levels decrease.

Water fleas are often indicators for low dissolved oxygen and water toxicity. Under low DO, Daphnia produce hemoglobin to increase oxygen efficiency. This hemoglobin turns water fleas reddish-pink causing red streaks to appear in your lagoon. When operators see red water fleas, they should consider treating the lagoon with aeration or mixing. Given their low tolerance to toxicity and short generational cycles, Daphnia are also used in the EPA's whole effluent toxicity tests (WET).

Now that we have a better understanding of water fleas, we can appreciate this microscopic view of Daphnia as told by Sacramento Splash. The video reviews the natural life cycle and anatomy of these helpful water crustaceans.

Featured Video: Flushable Wipe's Effects on Our Sewer System

Many collection systems struggle to prevent the costly and time consuming repairs associated with flushable wipes. Despite the label these wipes remain intact in sewer systems. They often clump into large blockages held together by grease. When the blockage becomes too large, sewers experience sanitary backups and pricey pump damage. 

This week’s featured video reviews the management options for flushable wipes as explained by Great Lakes Water Authority. One common solution for wipe buildup requires the installation of sewer grates and filter screens. Though operators will be required to regularly clear away wipe accumulation, systems can plan for the added maintenance expenses while preventing unexpected downtime. Other systems may choose to break down wipes with chopper pumps or grinder pumps, however this can lead to reweaving later in the collection system.

The video ultimately demonstrates that there is no single and efficient method to avoid wipe backups other than consumer education. With the final costs of wipe maintenance funded by the rate-payer, collection systems should be vocal in educating their customers about the products that can and cannot be flushed down the toilet. For more information on flushable products, check out our blog post Will it Flush.

Featured Video: Smelly Lagoon? Diagnosing and Correcting Lagoon Odors

As weather begins warming up for spring, many lagoons system owners have to manage odor issues and water turnover. In this week’s featured video, an experienced “Lagoon-atic” describes what causes lagoon odors and the best practices to manage them.

The most dreaded odors from lagoons systems are caused by sulfur dioxide and hydrogen sulfide gases. These gases emit a rotten egg odor that often leads to complaints from locals in the area. Under oxygen-stressed conditions, insufficient dissolved oxygen (DO) levels favor anaerobic digestion of biological oxygen demand (BOD) and sludge by sulfur bacteria.

This video also discusses the earthy smell of a healthy lagoon and other odor causing problems a lagoon may experience. Grassy odors indicate high levels of algae favored by warming temperatures, long detention times, excess sunlight, and excess nutrients. As spring approaches the solubilization of solids from the sludge blanket can cause nutrient release. This issue can be corrected by a reduction in the sludge blanket. Fishy odors may result from cyanobacteria growth under conditions with warm temperatures, high nutrient levels, thermal stratification, and still water. The longer water remains still, potential for cyanobacteria growth increases. Cyanobacteria can be reduced with chemical control, aeration, circulation, and ultrasonic waves. 

Spring time has potential to pose many odor issues for lagoon systems. Operators can maintain a healthy lagoon by ensuring sufficient DO levels, controlling sludge buildup, and mixing.

Featured Video: The Future of Water

Water is a scarce resource for many communities around the globe, and this scarcity is becoming more and more widespread. Our featured video this week from Quartz Media looks out how one locality half a world away has addressed this challenge, and how the rest of us can learn from systems like these where the "future of water" has already arrived.

While this video focuses on a larger metropolitan area, there are some interesting takeaways for smaller systems as well such as:

•  Solutions to water challenges are best solved at the individual and/or community level. 
•  Water reuse is most likely already happening in your community and efforts can be made to change public perceptions. For example, a wastewater pipe enters the Mississippi River every 8 miles - meaning almost every community using the river as a water source is already drinking someone else's wastewater!     

Spooky Sewers and Things That Go Bump at the Treatment Plant: 2018 Edition

Featured Videos: Small Communities Benefit From Shared Resources

The Small Communities Environmental Infrastructure Group assists small Ohio communities in finding resources to help solve their infrastructure and funding problems. These two videos feature water and sewer district officials and staff discussing the benefits of participating in SCEIG regional partnerships in order to better serve their communities. 

Featured Videos: Solids and Sludge Handling

How are solids handled and sludge thickened in the wastewater process? Watch this RCAP video to find out how one wastewater plant uses a dissolved air flotation thickener to settle sludge out before the digestion process and then uses a centrifuges for de-watering.  

Need to simplify the process? Check out how this small wastewater plant in Ohio reduces the free water content of its sludge - all for under $300 out of pocket cost. 

Looking for more videos on the wastewater treatment process? RCAP offers a free 7-part video series to explain the technical steps in the process of treating wastewater. 

Featured Video: Using Decommissioned Wastewater Tanks for Fish Farming

Just when you think you've seen it all, someone comes up with a crazy idea that holds some promise. This just might be true in the case of a local aquaculture businessman, who, along with a Kentucky State University researcher, looked at outdated wastewater treatment plants and source water reservoirs and envisioned profitable fish farms! 

This week's featured video explains how Steve Mims and Tim Parrott used a USDA grant a few years ago to turn decommissioned wastewater plants into working aquaculture farms (pg. 8) using treated effluent in digester tanks and daphnia (as fish food) from upgraded facilities that are often just next door. The tanks don't generate waste because the water cycles right back to the treatment plant.  

His big idea? To establish regional fish hatcheries through public-private partnerships, with young fingerlings sold to local farmers to raise in their own ponds all the while adding commercial-level fish and caviar production to the rural economies of Kentucky. So add fish farming to all the creative ways to recycle wastewater that people have been coming up with recently!  

Featured Videos: Onsite Wastewater Systems

According to the US Census Bureau, one in four homes in the U.S. is served by an onsite wastewater system. Our first featured video this week explores some of these onsite options and then explains in simple terms how each of these systems work in different soil conditions and what it takes to maintain them. In the end, the video shows how the cost-effectiveness of septic systems can often more than outweigh the cost of a centralized system for many smaller communities. 

Wondering how to find the funding to get these types of decentralized systems off the ground? Our second video this week explores how innovative partnerships and Clean Water State Revolving Funds can be used for exactly these kinds of projects.