Leachate Treatment Plant Design

Leachate Treatment Plant Design strategies can vary quite considerably because the individual requirements for leachate treatment on each landfill site varies site by site, and through the life of each site. The starting point for any Leachate Treatment Plant Design is always to establish the strengths, composition and volumes of leachate and predict those into the future at least for the initial design life of the leachate treatment facility proposed. The expert skills available from the Leachate Expert website www.leachate.co.uk can assist you in the specification, design, build, installation and commissioning of the most appropriate solution for your site. Within our expertize is also the operation and maintenance of the plants designed by the "Leachate Expert".

Process Design and Implementation - Based on a minimum of information we will work with our clients to provide a practical and economical process design which will then form the foundation of the project. Each project engagement can range from providing feasibility studies, design layouts and process flows, project management, specification, HAZOP’s, P&ID’s, landfill products and plant support.

Leachate Treatment Plant Design is evolving, and will continue to do so as modifications in landfill practices continually add the higher polluting risk arising from sanitary landfill leachates at many landfill sites. Historically, and up and until the early 1970′s, sites for the disposal of domestic wastes were normally small and provided for local waste disposal needs only, each serving a fairly minimal geographical area. Controls applied by regulatory authorities were very basic. These sites were also characterized by reduced input rates, high ash content of wastes from open fires and at the site, combined with the low densities of uncovered wastes which allowed all the waste to continue to gain access to air, and offered a level of negative environmental effects that were typically only locally felt and restricted in severity.

How Does a Modern Landfill Work?

In those days there was little or no Leachate Treatment Plant Design, because smoke, flies and vermin, combined with iron-staining and developments of fungi and micro-organisms in neighborhood streams, were generally tolerated as the acceptable cost of waste disposal. However, everything has changed now, and in most nations the savings from disposal of domestic wastes in what were no more than un-engineered and largely un-controlled “dumps” or “tips”, are considered not worth the environmental damage they do.

Now Leachate Treatment Plant Design is a specialist and highly technically sophisticated subject due to the high strength of modern leachate, and in most countries (unless pre-sorting removes a high proportion of putrescible waste) there is still a a continual increase in wastewater strength. Also, in recent months the volume of wastewater generated at many landfills, due to a wet winter, has exceeded the treatment capacity, resulting in an increase in wastewater being hauled to off-site disposal. To eliminate hauling, and meet more stringent discharge standards from the local POTW a new or revised Leachate Treatment Plant Design may be needed.

The Leachate Expert at www.leachate.co.uk is involved in the evaluation through design and construction of new and better (lower cost) leachate treatment plants. Initially, The Leachate Expert will evaluated plant flow and wastewater quality data to determine the required capacity. The Leachate Expert then prepares a management plan to address the different scenarios available to the site for leachate wastewater disposal. These scenarios investigated usually include: (1) pretreatment and discharge to either a public sewer, (2) or the landfill (i.e., recirculation), (3) complete treatment and reuse on site; and complete treatment and watercourse discharge.

Back to Basics in Landfill Leachate Treatment

Landfill leachate is generated from liquids existing in the waste as it enters a landfill or from rainwater that passes through the waste within the facility. The leachate consists of different organic and inorganic compounds that may be either dissolved or suspended. An essential part of maintaining any landfill is managing the leachate through proper treatment methods designed to prevent pollution into surrounding ground and surface waters. Even when a landfill is located in an arid area, leachate may be produced during wet weather periods, and its consideration remains necessary, although management may be by evaporation in many cases.

If leachates have a distinguishing characteristic, it is that flows are variable. Flows change according to the weather. The highest leachate generation will occur after rainy periods, decreasing during dry and when the leachate from previous events ceases to percolate through the waste and appear at the base of the landfill. Therefore, waste concentrations can change dramatically according to the weather conditions and as the waste matures over the life of the landfill. It follows that, no landfill leachate is constant over time, and no two leachates are the same. However, large landfills operated according to the EU landfill directive with less than 50% recycling taking place before it reaches the waste are remarkably similar when age of waste and leachate is taken into account.

Landfill Leachate Treatment Strategies

Landfill leachate treatment strategies can vary quite considerably subject to the individual challenges on each site as well as relative strengths, composition and volumes of leachate. The experts at the "Leachate Expert website" (see www.leachate.co.uk ) have designed dozens of successful leachate treatment facilities over the last 25 years, and can assist you in the specification, design, build, installation & commissioning of the most appropriate solution for your site. Naturally, we can thereafter provide operation and maintenance services.

Based on a minimum of information the leachate experts work with their clients to provide a practical and economical process design which will then form the foundation of the project. Each project consultancy involvement can range from providing feasibility studies, design layouts and process flows, to project management, specification, construction procurement, landfill product selection, HAZOPs, P&IDs, etc, and plant operational support.

A very wide range of treatment processes have been applied to leachate treatment with varying success. The processes which have been consistently successfully applied, for municipal waste landfill leachate from controlled landfills, are biological processes designed by specialist leachate process designers.

In many countries standard national discharge consents limit the applicability of biological processes due to their high stringency of the purity requirements, and removal of salts. Thus can be the result of consents which are designed for simplicity as national standards, and which adopt a requirement that all discharges must meet a high quality standard suitable for all cases.

Regulators often suggest that leachate should be pumped to a sewer for treatment at a urban Wastewater Treatment Plant (WWTP). However, this may historically have been driven by concerns that leachate treatment on site is challenging and difficult to achieve reliably, than by a detailed appraisal of the best options available. This however is no longer true, especially for designs from experienced specialist LTP designers, such as those at the "Leachate Expert website".

Is Leachate Treatment at Any Sewage Works A Good Idea Environmentally?

In reality it is not usually a good policy to treat strong leachate from modern sanitary landfills after discharging it into sewer. The act of mixing it with sewage makes it more difficult to treat by sewage treatment plants. Sewage works are not designed for such high ammonia effluents. Leachate has an extremely high ammoniacal nitrogen ("ammonia”) concentration when compared with the much weaker contamination levels in domestic, commercial, and industrial foul sewage.

This is why treating strong leachate at a Wastewater Treatment Plant, as if it were sewage, is  not efficient and leads to unnecessarily cost. Unless the WWTP has a high efficiency nitrifying process set-up already ammonia removal may be very poor. The result is that ammonia, which is one of the most potentially damaging types of contaminants in leachate, may simply be being diluted by its addition to sewage which is much weaker in ammonia, and the WWT may comply with its discharge consent by dilution, and even not treat the ammonia.

What Every Leachate Treatment Engineer Should Know About Contracts

O.K.! In our headline we have to admit that we changed the title to add in "Leachate Treatment", and the course we are recommending here is a general course, aimed at all engineers. However, the IChemE Forms of Contract are particularly useful for those like Leachate Treatment Engineers and Managers, who need a form of contract which is designed for a process plant.

The ICE offers similar courses, but for a leachate treatment plant contracts they are not nearly as good, because they are all about getting a structure built, and nothing much beyond that.

Process Plants are different. A bridge is finished and providing value as soon as the red-tape is cut, and the road over it, is opened. 

A process plant is different. To have a process plant built and sitting there is no good to anyone. A process plant like a leachate treatment plant, has to be commissioned, and working to produce the treated effluent to the quality specified by the discharge consent.

There are IChemE Forms of Contract for process plant contracts which suit every type of financing as well, so attending this course is really important for those in the leachate treatment industry, and if you are active in this area, we recommend attendance.

The details of the course follow:

The "What Every Engineer Should Know About Contracts" course will provide you with a
detailed understanding of contract law as it relates to engineering and construction contracts. It is taking place twice in the UK this year: 1-2 May in Rugby and 15-16 October in London.

Suitable for engineers of all disciplines, the course examines the law of contract and of tort within which engineering and construction contracts are made and operate.

It also looks at:

• the structure and essential contents of these contracts risk allocation and its links with payments
• the role of the contract administrator why the various standard forms of contract say what they say 

It is ideal for managers involved with contracts, particularly those who have moved into a procurement, project or contract management role, as well as engineers who are developing their skills across the range of business activities.

Click here for full course details and to register

Download the course brochure

You may also be interested in: 

IChemE Forms of Contract

12-13 June 2013, Redcar, UK
19-20 June 2013, London, UK

Helping those who will prepare, tender or manage a contract using the IChemE forms to understand their structure, main provisions and features, and the key differences between them. Fully updated to cover the new 2013 suite of UK contracts. Find out more here.

Please note that this is not a sponsored recommendation. We make no money from the course promoter if you attend.

What Is A Membrane Bioreactor?

So you desire to understand what this really is? You would be surprised how often individuals inquire about that question by seeking the world wide web. That's the reason we now have composed this article to describe what family or friends will feel you unaware or even ridiculous for inquiring the things they might think would have been a foolish issue.

In principle, a membrane bioreactor combines biological treatment with a separation process using microfiltration membranes. An advantage of the net is that you can ask these queries about just about any topic, and always with no stress that your buddies think of what you ought really to already know about!

So, I want to now get on with answering your problem by what a membrane bioreactor or "MBR" really is.

It is a sophisticated water treatment system commonly used for strong organic effluent treatment as in for example the aerobic treatment of landfill leachate.

First, a Membrane Bioreactor consists of a reactor tank and a microfiltration unit, which can be defined as: the use of membranes to allow the almost complete elimination of suspended solids from the effluent, with the conservation of all bacteria in the reactor while also removing BOD and COD and ammoniacal nitrogen concentration which is largely converted to the nitrate form in solution.

To make that clearer, here is a list of instances in which a membrane bioreactor might be used, as follows:

• It is also an MBR when referred to by many people, and also some will include an 
• MBR in a Reverse Osmosis Plant when treating landfill leachate.

So let's attempt to simplify items.

These can be classified into the following types of MBR Plant,as follows:

• MBR with Reverse Osmosis, 
• MBR with Activated Carbon, 
• MBR with Nanofiltration etc.

The main of those is:

MBR with Reverse Osmosis

Their unique characteristic is the fact that in the reactor, the micro-organisms which are mostly bacteria transform dissolved polluted matter into biomass, and NH4 nitrogen (“ammonia”) into nitrate. In this way biodegradable organic contaminants are eliminated by the bioreactor as well as a number of metals which are oxidized into mostly insoluble compounds. The suspended solids are then eliminated from the flow by the microfiltration membrane.

The key issue, to consider about membrane filtration, is that it allows the retention of non-soluble molecules having a high molecular weight and in that way increases their residence/retention time and also as a result increases the extent to which of biodegradation occurs inside the biological reactor (bioreactor).

Now that you have see this article you should know far more about the use of membrane bioreactors or "MBRs" for leachate treatment, and this will, we hope have made it easier for, you. 

Using this method of this research you have applied the services of the net intelligently to answer a really distinct query which can be important to you at this time resolve. 

Now reader, you can instantly compliment yourself for your learning and by educating yourself, most of us need to obtain increased good results in your lifestyles, so we surely think that you're going to experience that as well

Uncover how you can use the MBR with Reverse Osmosis treatment system by visiting the membrane bioeractors page on the website at leachate.co.uk/main/leachate-treatment/how-a-membrane-bioreactor-is-used-to-treat-landfill-leachate/.

Answers to Current Questions Being Asked About Leachate Treatment

We have compiled a list of the most common questions being asked at the moment about leachate treatment and leachate management for landfill sites. Top of the list of these are:

1. What Is Leachate?
2. What Is A Leachate Attenuation Zone?
3. How To Calculate Leachate Generation?
4. What Are Leachate?
5. What Causes Leachate?

These are all questions which are answered at our main web site at www.leachate.co.uk .

However, to assist our readers I will provide quick answers below:

1.What Is Leachate?

Leachate is the contaminated liquid which runs out of another material, in our case we are talking about landfill leachate, and the dirty water that accumulates in, or runs out of the bottom of, landfill sites.

2. What Is A Leachate Attenuation Zone?

A Leachate Attenuation Zone is a soil material which is only partially permeable through which leachate flows (usually by gravity) and as it flows through slowly it becomes less contaminated ("cleaner"). The reduction in contamination can take place by biological action or by physico-chemical action.

3. How To Calculate Leachate Generation?

This can be difficult and there are several sophisticated water balance modelling softwares which will attempt to do this for you. The problem with using them is in understanding how they work and whether you can trust them to give the right answer. I usually carry out a water balance using  a spreadsheet, on an annualized basis. Contact me if you need assistance with a water balance problem for a landfill at http://ipptsassociates.co.uk/contact/  .

4. What Are Leachate?

Although this comes up as a question a lot online, it is grammatically incorrect and makes no real sense. See answer 1. above.

5. What Causes Leachate?

In modern landfills which do not accept liquids for disposal, it is mostly the organic matter (food scraps, grass mowings etc) which are in a municipal waste landfill which decay to form leachate. During decay, the cells of the organic material rupture and the contents of the cells dissolves in rainfall trickling through the leachate producing a smelly, and quite often black liquid which over time (if left in the landfill) usually turns into an amber liquid which often smells of ammonia, but may just smell "earthy".

For more information about commonly asked leachate questions visit our website at the leachate expert  .

Anaerobic Digestion News: UK Energy from Waste - Don't Get Hurt By The Waste...

Anaerobic Digestion News: UK Energy from Waste - Don't Get Hurt By The Waste...: Take care energy from waste people - Don't let the Waste Hierarchy Bite! The topic today is the UK Waste Regs. and how important it is w...

Toxic Waste Disposal and Landfill Gas Risks from Sandy Superstorm Aftermath

Those responsible for toxic waste disposal are working alongside the other public bodies to clear up the damage from the recent Sandy Superstorm (hurricane) in the eastern states of the US at the end of October 2012.

An urgent issue is the collection and safe disposal of many paint, oil and other miscellaneous drums of material which has been washed out of properties during the storm surge in areas such as Long Beach.

Steve Last also highlights the risk of unexpected landfill gas emerging from previously dormant abandoned landfills which may now have become wetted where they were previously dry and starting to produce methane again even for the first time.

Those that read this blog would not be wrong to suggest that at the same time there may be leachate problems if the waste has been flooded and then produces leachate.

See the full article at the following link:
Toxic Waste Disposal and Landfill Gas Issues in Sandy Superstorm Aftermath

Sanitary Landfill and Leachate

I was blogging recently about sanitary landfill leachate when from a reader's query it became clear that they were not clear about what a sanitary landfill comprises. In this article I set out to put that right.

Migration Hazards at a Sanitary Landfill (Image: Masterplan
for the Aftercare of Abandoned Landfills, Van Vossen, Gravesteijn,
Kasma  and Vos; proceedings Sardinia 95, 5th Sardinia Landfill
Symposium Cagliari, Italy)

The standard definition of a Class III or "Sanitary Landfill" originates in North America and the term has spread around the world from that source. It is, as defined in the US, a landfill that accepts household garbage and is normally lined below to reduce the escape of leachate to an environmentally acceptable rate, operated to minimize leachate generation and keep the waste as dry as possible, and capped as each area of the landfill is completed - again to keep leachate to a minimum but also to allow efficient collection of the landfill gas the landfill produces. The best sanitary landfills also have a recycling center at the site or the waste passes through a recycling center before it reaches the sanitary landfill. The recycling center these days often includes processing which separate waste types and process the waste, and comprehensive centers where waste is reduced, recycled and reused are called MRFs, and some are also known as MBT Plants.

The modern sanitary landfill is lined in the US with multiple layers to protect soils and the water bearing aquifers underneath. The in the US liner is composed of multiple natural layers and an impenetrable plastic (HDPE) or similar material. The purpose of the liner is to hold the waste for as long as possible collect all the "garbage polluted rainwater" (known as leachate) so that it can be extracted and treated. In Europe and worldwide the plastic lining is usually a single layer of thicker material than is usual in the US.

The new environmental centers being built for many sanitary landfills offer the opportunity for the community to become a more sustainable community. It will not only enhance the area's management of its waste but will also provide state-of-the-art and innovative recycling and in many cases the production of renewable energy.

Sanitary Landfills in More Detail

In short sanitary landfill is simply a general description of a type of landfill, it is the commonly accepted method of controlled disposal of municipal solid waste (refuse) on land in most countries. The method was first used in England from 1912 (where it has was then called controlled tipping, and is now called controlled landfilling). Waste is deposited in thin layers (up to 1 metre, or 3 feet deep) and within hours compacted by heavy compaction machinery (known as "compactors" these are similar to bulldozers but instead of having tracks have steel cutting wheels to break up the waste). Several layers of waste are placed and compacted on top of each other over a period of a day to several days, to form a refuse cell (up to 3 metres, or 10 feet, thick).

At the end of each day the compacted refuse cell is covered with a layer of soil material (or similar) to prevent odor, keep rats out of the waste, and prevent windblown litter from being blown of the site. All modern landfill site locations are carefully selected and prepared before the waste is placed. They are sealed with impermeable synthetic bottom liners to prevent pollution of groundwater from leachate or other environmental problems.

When the landfill is completed, it is capped with a layer of low permeability material such as a clay, or a synthetic liner, in order to prevent as much water as possible from entering. A final topsoil cover is placed, compacted, and landscaped, with various forms of vegetation being planted to reclaim the surface for the planner after-use.

Traditional landfills, before sanitary landfills were introduced were referred to as “open” or “polluting” dumps, simply containing un-engineered sites with waste under the ground. Such sites potentially allow the waste by-product called leachate to enter and contaminate groundwater and other water sources. They also attract rodents, insects and other disease-carrying vermin. Other negative effects of open dumps include emission of air pollution, odors and the creation of potential fire hazards. In a sanitary landfill these risks are partly eliminated, or at least deferred thanks in part to protective liners and monitoring systems that ensure there is no harm done to the environment, for just as long as the leachate is removed and treated.