Acid Tar Lagoon

Category : Article



Hoole has a remarkable "Acid Tar Lagoon". The lagoon arose as a result of over 62000 tonnes of liquid acid tar waste from benzole refining being poured into the excavated clay pit of a brickworks until 1967. This article looks at a history which starts with an English colony in Peru and ends in a field in Hoole.

Benzole
Benzole is a noxious coal-tar derivative. It was once produced as a by-product of the manufacture of coke by heating coal in a closed retort. This drives off coal gas which was once used extensively for lighting as "Town Gas". Town Gas contains hydrogen, carbon monoxide and flammable hydrocarbons. It has a characteristic smell due to some sulphure-containing impurities. The remaining coke was used for heating and in a variety of industrial processes.



As well as gas and coke a "gas works" also produces coal tar, which has both medical and industrial uses. Coal tar was discovered circa 1665 and used for medical purposes as early as the 1800s. Circa 1850, the discovery that it could be used as the main ingredient in synthetic dyes engendered an entire industry. In the coal gas era, there were many companies in Britain whose business was to distill coal tar to separate the higher-value fractions, such as naphtha, creosote and pitch. Many industrial chemicals were first isolated from coal tar during this time, yet coal tar is a very complex mixture and many of its components, especially those present at low levels, remain unidentified. Some well-known pharmaceuticals, such as paracetamol, were first manufactured as coal-tar dervatives. When Arthur Conan Doyle wished to demonstrate the character of Sherlock Holmes in "The Adventure of the Empty House", he has him explore Tibet, visit Mecca, travel to Khartoum and then do research on coal tar derivatives in Montpellier.

Benzole (or benzol) is the term used in the UK for a coal-tar product consisting mainly of benzene and toluene. It was originally used as a "motor spirit", as were petroleum spirits and alcohol. Benzole was also blended with petrol and the combination sold as a motor fuel. Use of Benzol as a motor fuel was particularly prevalent in Germany after WW1 when the country was isolated from supplies of petroleum and needed a "synthetic" alternative. At the time most of Britain's coke ovens did not recover Benzole and the the crude by-product was exported in an unrefined state. In normal benzoles produced by high-temperature coal-gas processes, the aromatic hydrocarbons may be assumed to be roughly in the proportion of 70% of benzene, 20% of toluene and 10% of xylenes or solvent naphtha. Actually, the proportions in which the constituents are present vary considerably, depending on the character of the coal carbonised, the conditions of carbonisation, and subsequent processing. Benzole can be a fair or poor motor fuel depending on its composition, but it has the advantage that the addition of benzene to petrol increases the octane ratio and reduces knocking. On the down-side engines begin to soot very quickly which results in a decrease of power and possible failures. However by 1927 National Benzole was a nationally established fuel brand in the UK, best known for its 50:50 blend of benzole and gasoline. Benzole, because it is a source of benzene and toluene, is also an important feedstock for the manufacture of many other chemicals such as dystuffs and explosives.

Crude benzole contains small quantities of a large number of impurities which consists of the unsaturated and sulphur compounds. One of the effects of these materials is to create a poor fuel. For the manufacture of explosives, such as TNT, particularly high grades of toluene are needed, and this requires a "catalytic" refing process. Crude benzol contains sulphur compounds (and other things) which will "poison" the catalyst and the refining of benzol therefore assumed a military as well as an economic importance.

To remove the impurities, the crude benzol is washed with concentrated sulphuric acid which sulphonates the more undesirable compounds and allows easier separation and recovery of the benzene, toluene and xylene (BTX) fractions. The sulphuric acid washing removes unsaturated compounds, olefins, dienes etc. together with any pyridine and some sulphur compounds. The sulphuric acid treatment produces a thick, dark brown residue which is known as "acid tar". In some processes a clay (such as bentonite) may be present in the mixture. The sludge deposited into the pit at Hoole consisted of a mixture of tar-like hydrocarbons. which included spent bentonite and absorbed heavy oil, sulphuric acid and other oily substances. The acid-tar process has now been superceeded by "cleaner" methods.



Gunpowder contains the nitrate saltpetre. In medieval times enough of this could be obtained from dung-hills and latrines. By the mid-19th century, however, far more powerful explosives like nitroglycerine and TNT were being prepared by using a mixture of concentrated nitric and sulfuric acids to attach nitrate groups to suitable organic molecules. The critical raw materials were now caliche – a nitrate-rich mineral from Chile – and organic substances from various sources, particularly benzole from coal tar. In 1914, existing stockpiles of explosives and their chemical precursors proved woefully insufficient, even for the expected short war. One of the reasons that WW1 developed into a trench stalemate was that neither side had sufficient ammunition to break-through. There are some suggestions in the literature that Benzole itself was used as a shell propellant in WW1, although this may be an error with benzole only being used as a raw material for the manufacture of explosives.

By the Second World War it had become clear that petrochemical and fuel supplies were of immense srategic military importance. This was especially true given that most of the European powers had little or no natural supplies of oil. When Adolf Hitler took control of the country in the 1930s, he was keen to develop a domestic synthetic fuel industry. When WWII started, synfuels refined from coal were a significant contributor to Germany’s energy needs. Benzole had become a strategic material.

Lobitos
Lobitos is a now something of a ghost-town located on a somewhat desolate stretch of the northern coast of Peru in the region of Piura. It is known as a small fishing town and is famed for its surfing among those willing to travel to out of the way places, but has a long history of oil extraction dating back to the late 19th century. Indigenous people in Peru used the heavy oil/tar to waterproof baked clay containers, for medicinal purposes, and in lighting during religious ceremonies. Later the colonising Spaniards used it for caulking their ships. The first significant enterprise there was led by Balfour Williamson & company. Balfour Williamson & Co was a shipping company based in Liverpool, and later an export confirming house and freight forwarding company. The company was founded in 1851 by two young men from Fife, Scotland, Alexander Balfour and Stephen Williamson. They were joined for a time by a third partner, David Duncan. The company traded with South America, and had offices in Valparaiso, Chile and San Francisco. They built up a significant trading network along the Pacific coast of South America and established the "Peruvian Petroleum Syndicate" with other partners in 1901.



The first wells at Lobitos were drilled in 1903 but actually turned out to be uneconomic. New and deeper wells were again drilled in the northern zone of Lobitos in January 1904 and these turned out to be much more viable. As of March 13th of 1908 the Peruvian Petroleum Syndicate ceased trading under this name and Lobitos Oilfield Company was established in London with shares being sold on the stock market. Lobitos had become something of a strange colonial outpost, with substantial Victorian houses of which a few still remain. Then came world war one and the beginning of American political muscle flexing abroad in regards to national security interests that included petroleum. The American Government felt that the British interests in Lobitos were too close to home and therefore exerted lobbying pressure to enable the International Petroleum Company (the Canadian Subsidiary of Standard Oil of New Jersey, later to become Exxon) to buy a 50% share of Lobitos Oilfields. By the 1920's Lobitos Oilfield was producing 20% of Peru's oil.

The town and surrounding land was thereafter a mini British/ American colony that was legally leased from the Peruvian Government, in which much needed infrastructure (pier, desalinization plants, electricity, cattle ranch and slaughter house, hospital roads etc.) was established for production and the needs of immigrant workers settling in the new town. On a rather deserted stretch of cosatline at the northen end of the Sechura Desert it is one of the most arid places on earth. At one point the most luxurious ocean liners in the world such as the SS Cuzco and SS Reina del Pacifico stopped off in the bay on their route from Liverpool to Santiago de Chile - if only because there was no other stop-off anywhere nearby. The Prince of Wales and Prince George visited Lobitos in 1931 on their way to the World Expo in Buenos Aires, Argentina. Such was the importance of this town, the first cinema in the South American continent was established there.

In 1934/5 Lobitos Oilfields opened a refinery at Elesmere Port connected by a pipeline to Stanlow Docks. This was one of the first petrochemical facilities in the major expansion at Ellesmere Port from simply a storage location. Bulk imports to the port had started in 1922 and by 1934 the storage capacity was 90 million gallons. Shell then purchased a large area at the mouth of the Gowy and by the outbreak of WW2 a wide range of petrochemical products were being produced. One consequence of this developing industry was that it attracted the manufacture of anti-knock compunds such as Tetra Ethyl Lead (TEL) to the area.



In WW2 the Lobitos company suffered casualties. At 11.00 on 11 January 1940 the EL OSO, in convoy HX-14B, struck a mine laid on 6 January 1940 by U-30 and sank six miles 280 degrees from the Bar Lightship, Liverpool. Three crew members were lost. The master and 32 crew members were picked up by HMS WALKER and landed at Liverpool. One injured crewman subsequently died in hospital. The first major casualty on the West Coast in WW2, she carried 9,238 tons of Peruvian crude oil, and 511 tons of casinghead gas. One of the products handled at the refinery in wartime was some of Britain's only natural oil from Eakring in the Newark and Sherwood district of Nottinghamshire - during the war, the Nottinghamshire oilfield produced over 2.25 million barrels (358,000 m3) or perhaps 3.5 million barrels (560,000 m3) of oil from 170 pumps ("nodding donkeys"). Just why the Nottinghamshire oil was taken to Stanlow is unclear: it may have been a question of capacity, or it could have been that the oil was of a kind which required special refining techniques available at Lobitos.

Benzole as an alternative motor fuel was eventually phased out. Benzene and toluine are both far more toxic than petrol and the price of petrol fell below that of benzole. Alternative anti-knock cdditives also became available, although one of these (TEL) was lead-based and that caused significant release of lead into the environment. Production of TEL at Elesmere Port continued long after it was banned in most countries but as of 2020 is believed to have ceased.

Bricks
Any glance at a map of Upton, Newton and Hoole immediately suggests the presence of clay. There are many glacial features in the lamdscape and a notable number of marl pits. Reference to a geology text will confirm that there is a layer of glacial clay over the underlying sandstone. During the Georgian and Victorian eras, brick became a popular building material and the growth of Chester northwards following the establishment of Chester Station, especially into Hoole demanded a ready supply of bricks.

Rolt Brothers and later Hartleys owned the Hoole Bank brickworks, although the existence of paperwork in other names suggests that it changed hands frequently. This could be taken to suggest that it was not a particularly profitable busiiness.

The process of brick making changed little over the years and essentially comprised: excavating and transporting the clay to the works; mechanical working of the clay through a pug mill where larger stones were removed or crushed and where water was introduced if necessary to bring the clay into a consistency where it could be moulded; squeezing a continuous slab of clay through a die which had the cross-section of a brick onto an iron table where it was cut into individual bricks by tensioned wires held in a frame; removal of the ‘green’ bricks by hand, on barrows, to the drying sheds which were heated by waste heat conducted from the kilns, removal of the dried bricks on barrows to the kilns, and; firing the kilns to bake the bricks using slack coal fed down tubes from a floor on the top of the kiln. The brickworks at Hoole bank does not appear on the 1898 OS map, but appears as quite extensive on the 1908 revision, suggesting that it was founded around 1900. The bricks manufactured would not be of the high quality Ruabon type used in much 1890's building in Hoole, but of a lower-cost single-fired variety.

It is not known when the brickworks closed, leaving a large pit from which clay had been extracted.



Waste
Acid tar production is a result of three chemical processes; benzoIe refining, white oil production and oil re-refining. The waste dumped at Hoole was from benzole refining as described above, with the disused claypit forming an appropriate receptable. Most books which mention acid tar lagoons will mention the Hoole site, although it remains remarkably poorly known in the area. Another site used for dumping acid tar was at Llwyneinion near Wrexham. In August 1980 that lagoon site caught fire, resulting in the temporary evacuation of nearby Rhosllanerchrugog.



Lobitos was taken over (1962) by Burmah-Castrol Company, now part of BP Anaco. The acid tar waste arrived at the dumping site warm in a semi-fluid state, and therefore was simply poured into the pit. At least 62,000 tonnes of liquid acid tar was poured directly into the pit together with spent bentonite containing absorbed oil. Some writers have failed to identify a source for the waste, but there are plenty of photographs in existence of Lobitos Benzole rail tankers on train-spotter sites from Ellesmere Port and Stanlow. In addition to the acid tar waste, several chemical drums were also fly-tipped into the sludge. However, nothing is known about the origins, contents or amounts contained within these drums. The unlined acid tar lagoon occupies 1.1 ha, ranges up to 9 m deep and is underlain by mixed glacial deposits over red sandstone bedrock of Permo-Triassic Chester Pebble Beds Formation. The heterogeneous tar waste has developed semi-solid tar layers, but most remains in a viscous and mobile condition. A surface layer of rainwater less than 0.9 m deep covers much of the waste.

In 2000 the contents of the pit were 44 % sulphuric acid, 42 % oil residues, 8 % sulphated oil residues and 6 % water. It was fenced-off in 1999, but there are seepages outside of the fence. Various strategies for remediation have been considered, but none implemented. Curiously, and seemingly by co-incidence the Barnett family of Hoole Hall, were the owners of "Rattlechain Lagoon" in Tividale (West Midland) later used as a phosphorous waste dump and another seriously contaminated site. The acid tar pit in Hoole has no apparent owner, Cheshire West & Chester Council would not wish to take on the ownership of what can be considered a poisoned chalice. The Environment Agency are happy that as long as it is fenced off from the general public that is the best that might be expected. The pit is not entirely devoid of life as some highly specialised bacteria are able to live under these extremely acid and toxic conditions.

In 2000 a eeport noted:


 * "Various remediation strategies have been assessed. They fall into two main categories; those involving encapsulation and on-site treatment of the acid tar and those aimed at removal of the material to facilities elsewhere in the country. Investigations and deliberations continue in order to determine the optimum way forward."

As of 2021 no action had been taken.

Sources and Links

 * A video of the acid tar pit;
 * Octel at Elesmere Port;
 * Biodiversity studies;
 * Hoole Bank House;