Deep ditch minimizes footprint
A goal of many communities in planning wastewater treatment facilities is to minimize the footprint, reducing land use. To reach this goal, a Chinese municipality built their oxidation ditch to deeper parameter depths than conventional designs but experienced serious process and mechanical issues.
Officials found that not all aerators are equal. For tackling this deep ditch activated sludge system, the right system was the Aire-O2 Triton® aerator/mixer.
The city of Lin An, in the Peoples Republic of China, is located about 31 miles west of Hangzhou, the capitol of Zhejiang Province. The city’s wastewater treatment facility is an oxidation ditch system with an influent flow of 10.5 million gal per day (mgd) with influent BOD is 200 mg/L, total suspended solids (TSS) at 200 mg/L, and Phosphorus at less than 3 mg/L.
The Lin An oxidation ditch has a total water depth of 13.7 feet, nearly twice the depth found in conventional brush rotor type ditches that are approximately 6 to 8 feet deep.
European processor eliminates maintenance headaches - Case Study
Problem Wastewater treatment became a huge headache for this large, European sugar processing company. The plant had installed many different types of aeration equipment in its activated sludge, aerated lagoon system. The company was dedicated to meeting all the environmental standards for its country. In their quest to find the best equipment, they had tried submerged pumps, propeller mixers, and compressed air, diffused air. Still, treatment was unsatisfactory and maintenance was time consuming and very...
A Site-Specific Tool for Optimizing Final Clarifier Design and Operation
The final clarifier is one of the most important unit processes and often determines the capacity of a treatment plant. Clarification is a solids separation process, which results in the removal of 99 percent or more of the suspended solids (biological floc) received from the activated sludge system. The separated solids are transported to the bottom of the clarifier and removed as return activated sludge (RAS). The clarifier failure can lead to solids carryover resulting in a reduction in solids retention time...
Evaluating Denitrification Filters
Untitled Document Before selecting a denitrification filter, designers should compare all available systems and assess their performance to date With the development of total maximum daily loads for nutrient discharges, many wastewater treatment plants (WWTPs) face stringent nutrient limits. Deep-bed denitrification filters that remove nitrogen and solids are a proven technology for treating wastewater to meet low total nitrogen (TN) limits. A variety...
Aerators Enhance Aerobic Digestion Process
The city of Eden,N.C.,operates an extended aeration process designed for an average flow rate of 13.5 mgd with a mixed liquor suspended solids concentration that typically checks in about 6,000 mg/l. This high biomass concentration is necessary to provide a well-settling sludge and good effluent quality. Further, the plant influent is approximately 40% domestic wastewater and 60% industrial wastewater. The industrial component is dominated by textile facilities.The Eden Wastewater Treatment Plant (WWTP) generates...
Fire Prevention at Composting, Mulch Facilities
Untitled Document AS we examine the causes of fires experienced at compost and mulch facilities, we discover some commonalties: Fires are more likely to occur where the piles are dry, and have enough porosity to allow heat and air to enter or leave. Older, large, deep - and especially ignored - piles can be a problem! The composting process benefits from the ability of the mix of ingredients and microbes to be self-heating. This property drives compost drying, physical degradation,...
Heritage Marketplace Field Evaluation: Stormwater Management StormFilter with CSF Leaf Media
As part of a performance assessment of the Stormwater Management StormFilter® (StormFilter) in Clark County, WA, a StormFilter system using CSF® leaf media installed at Heritage Marketplace was evaluated between March and July of 2002. This StormFilter system treats stormwater runoff draining from the rooftops and parking lots of the Heritage Marketplace shopping center. This StormFilter system was evaluated to determine removal of various pollutants running off the site, including total suspended solids...
Performance of Floating Horizontal Aerators in Aerated Lagoons and Oxidation Ditches
INTRODUCTION When selecting aeration equipment to use for a specific application, issues to address include reliability, serviceability, capital cost, system appurtenances, and cost of operation and maintenance. Another important consideration is oxygen transfer rate (OTR). Horizontal floating aerators have relatively high transfer rates and have been used successfully in aerated lagoons and oxidation ditches. Using equipment with high OTR values reduces the horsepower input that is required and subsequently...
Enhancing the Performance of Oxidation Ditches
ABSTRACT Oxidation ditches are very popular wastewater treatment processes for small to mediumsized municipalities that have to meet stringent water quality standards. Oxidation ditches provide cost-effective treatment while requiring relatively simple operational skills. Because carbonaceous BOD removal, nitrification, and de-nitrification can be accomplished within a single reactor, the process can produce a high quality effluent. Obviously, it is important to adequately mix the wastewater with the biomass...
Fires at Composting Facilities: Causes and Conditions
The subject of fires at composting facilities is a bad news/good news situation. The bad news is that fires are more common than we realize. Ask a group of facility operators if they have had to deal with a fire, and the majority will quietly admit they have. The good news is that we don’t realize that fires are fairly common at composting facilities. Most are neither frequent nor destructive enough to attract attention beyond the facility gates, with notable exceptions. Generally, operators are recognizing and...
Wastewater Odors Go Under Cover
Problem: A new residential golfing community wanted to prevent odor emissions from the local wastewater treatment plant from affecting the lifestyle of its residents. Solution: Flat structural-fabric covers were installed over the treatment plant`s aeration tanks and primary clarifiers. Download the full article in pdf format (67 Kb)
Troubleshooting the Compost Pile
While composting is a biological process, we as composters must provide the microorganisms that do the work with the conditions they need to do their job. If there is a problem with the system, then look at it from the point of view of the microbe. What does that microbe need to function, and why isn’t it functioning correctly? Microorganisms need a source of energy organic feedstocks to feed on and draw energy. Some of that released energy causes the compost pile to heat. Besides energy, organisms need nutrients...
Composting Key to Meeting Landfill Organics Ban
The Halifax Regional Municipality (HRM) in Nova Scotia took a giant leap in 1998 to reaching a 50 percent diversion goal by 2000. Between July and November, 1998, organics collection carts were distributed to almost 100,000 households in the region. In December, two new composting facilities designed to process those materials, as well as feedstocks from the commercial sector, opened their doors. “The Halifax Regional Municipality’s new integrated solid waste-resource management system is ‘leading edge’ in all...
Achieving Pathogen Stabilization Using Vermicomposting
Within the last decade, implementation of state and federal regulations and other local codes have changed biosolids processing in Florida. Previously, biosolids stabilization varied greatly among the state’s 3,500 to 4,000 wastewater treatment facilities. Public and privately owned wastewater treatment facilities were required to stabilize their biosolids to a minimum Class C standard for land application, with most facilities using aerobic or anaerobic digestion. Requirements for septage solids stabilization,...
Bioremediation of Effluent the Pulp and Paper Industry
The treatment of industrial effluent from the paper manufacturing facilities in British Columbia is a major concern because the effluent is discharged into prime salmon habitat in the marine environment (Cross, 1994). High levels of biological oxygen demand (BOD) in the effluent reduce the dissolved oxygen (DO) available to species in the marine environment. In 1988, the Federal Department of Fisheries and Oceans reviewed the levels of DO and total suspended solids (TSS) that are discharged in the effluent...
Environmental Situation in Africa
Abstract Africa The economic and social needs of Africa depends more on its environmental resources but these natural resources are seriously declining and that is really effecting the entire region. Sustainable development in this rapidly changing region has become an imperative, and must take place in the complex context of a diverse and changing ecosystem, political transition and evolution toward market economies. The region is heading towards integrating environmental components into sectors like...
In Situ Physical/Chemical Treatment for Ground Water and Leachate
The main advantage of in situ treatments is that they allow ground water to be treated without being brought to the surface, resulting in significant cost savings. In situ processes, however, generally require longer time periods, and there is less certainty about the uniformity of treatment because of the variability in aquifer characteristics and because the efficacy of the process is more difficult to verify. Physical/chemical treatment uses the physical properties of the contaminants or the contaminated...
Common Treatment Technologies for Halogenated SVOCs in Soil, Sediment, and Sludge
Common treatment technologies for halogenated SVOCs in soil, sediment, and sludge include biodegradation, dehalogenation, incineration, and excavation with off-site disposal. All types of biodegradation, both in situ or ex situ, can be considered to remediate soils: in situ bioremediation, bioventing, composting, controlled solid phase, or landfarming. Slurry phase biological treatment is also applicable but is less widely used. Treatability studies should be conducted to evaluate design parameters, such as...
Introduction Land Treatment is a full-scale bioremediation technology in which contaminated soils, sediments, or sludges are turned over (i.e., tilled) and allowed to interact with the soil and climate at the site. The waste, soil, climate, and biological activity interact dynamically as a system to degrade, transform, and immobilize waste constitutes. Wastes are periodically tilled to aerate the waste. Soil conditions are often controlled to optimize the rate of contaminant degradation. Conditions normally...
Bioslurping - Technology Overview
ABSTRACT Bioslurping involves the simultaneous application of vacuum enhanced extraction/recovery, vapor extraction, and bioventing to address LNAPL contamination. Vacuum extraction/recovery is used to remove free product along with some groundwater, vapor extrac tion is used to remove high volatility vapors from the vadose zone, and bioventing is used to enhance aerobic biodegradation in the vadose zone and capillary fringe. The bioslurping system is made up of a well into which an adjustable length `slurp...
Two Case Histories of Industrial Water Reuse Via Membrane Technology
Abstract This paper describes two successful applications of ultrafiltration (UF) and reverse osmosis (RO) membrane technology used to reclaim water, reduce waste water discharge costs. The first case history covers oily waste water treatment at a major aluminum beverage can manufacturing plant. The second case describes treatment of waste water from a multi-plating bath section of a major wheelchair manufacturing facility. The mechanisms of separation effected by both UF and RO are described at the molecular...