Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/04—Aerobic processes using trickle filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F9/00—Multistage treatment of water, waste water or sewage
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/286—Treatment of water, waste water, or sewage by sorption using natural organic sorbents or derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/30—Treatment of water, waste water, or sewage by irradiation
  • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
  • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/36—Organic compounds containing halogen
  • C02F2101/363—PCB's; PCP's
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/06—Contaminated groundwater or leachate
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/30—Wastewater or sewage treatment systems using renewable energies
  • Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy

Definitions

• the present invention relates to a method according to the preamble of claim 1 for purifying chlorophenol-containing waters .
• the preservation of wood has been based on the open-tank, log bundle dipping and spraying methods.
• the open-tank method the individual pieces of timber are impregnated in a preservative solution.
• the bundle dip method entire bundles of timber are briefly immersed in a tank containing the preservative solution.
• the spray method the surface of timber is sprayed with the preservative solution.
• chlorophenols When spilled on the ground, chlorophenols may be absorbed in the soil or become transported with ground run-off water or rainwater to the waterways or groundwater. In the topmost layers of the ground, chlorophenols undergo a partial decomposition through biological pathways, but in the lower layers below the surface they have turned out to be rather stable. Chlorophenols have been found in saw mill sites even several decades after the termination of timber treatment with anti-blue-stain preservatives in the area.
• Chlorinated phenols are transported in waterways along with the water currents and ultimately bound with bottom sediments. In a waterway, chlorinated phenols may become enriched in the human food chain via the microfauna and fish thus posing a health risk. Chlorinated phenols reaching the groundwater present the most complicated case, because they do not undergo natural decomposition there owing to a too low temperature, oxygen supply and bacterial activity. From groundwater chlorophenols can also easily enter the communal water supply networks thus causing a health risk.
• contaminated soil is piled into an elongated heap in which beneficial conditions are esta ⁇ blished for the biological decomposition of chlorophenols .
• the decomposition process is performed by the native microbes (bacteria, fungi and enzymes produced by them) of the soil .
• An important precondition is that the environ ⁇ mental parameters such as temperature, pH, moisture content, nutrients and other factors crucial to the activity of the microbes are adjusted optimal. Neither may the compost incorporate constituents inhibiting the biological decomposition process such as toxic substances.
• suitable bacterial strains can be grown in separ ⁇ ate pure or mixed colony cultures and then added to the compost.
• the biological decomposition process can be further enhanced using various bioreactors or slurrying methods .
• Biological decontamination of chlorophenol-containing soil is a most suitable and cost-effective though time-consuming cleaning process for saw mills. Under favorable conditions the concentration of chlorophenols in the soil can be reduced in 2 - 3 years by composting to 1 - 5 % of the initial concentration. The treated soil can later be used as landfill, for landscaping and other similar use.
• Biological purification of chlorophenol-containing waters takes place basically in the same fashion as the biological decontamination of contaminated soil.
• precondi ⁇ tions temperature, pH, nutrients, etc.
• the purification process is seeded with bacterial strains grown in controlled cultures.
• Biological purification is most typically carried out in either existing wastewater treatment plants or purpose- built bioreactors.
• chlorophenols may cause disturbance to the normal purification process, whereby the usable chlorophenols treatment capacity remains small.
• the chlorophenols-decomposing bacteria are preferably bound with the bioreactor filler material or the fluidized bed solids to prevent them from leaching out from the reactor along with the treated water.
• the biological water purification process may reach a purification efficiency of 99 %, although the method is extremely susceptible to disturbances in the process.
• the chlorophenol-containing water is subjected to ultraviolet radiation.
• the UV radiation may be provided by the sun or an artificial source.
• the photochemical decompo- sition process called photolysis attains an almost complete purification result, while such factors as high water turbidity or dirt content may crucially impair the purifi ⁇ cation efficiency.
• the electrochemical purification process also attains an almost complete decomposition of chlorophenols in the water.
• the chlorophenol-containing water which may have a conductivity improving agent such as a salt added to it, is taken to an electrolysis apparatus.
• the electric current passing through the liquid then accomplishes the decomposi ⁇ tion of the chlorophenols .
• the process is controlled by the adjustment of the electric current and voltage and choice of the catalyst used.
• Adsorption as such is not an actual purification method for chlorophenols, but rather, it is utilized to bind chloro ⁇ phenols in a carrier material which is then easier to destroy.
• the most effective adsorbing materials include, e.g., activated carbons. Chlorophenols adsorbed by such materials can then be decomposed biologically by composting or thermally by incineration.
• a multistep method is used for purifying chlorophenol-containing waters.
• the theory of the method according to the invention is described in greater detail in a licenciate thesis by Erkki Salmenlinna under the title "Purification of chlorophenol-containing waters in conjunction with the saw mill processes of timber conversion", Aug. 15, 1993, Koski (H.L.) , Finland. In-depth test were conducted for the thesis to assure the function of the method according to the invention. The test results corroborate the applicability of the invention.
• the method according to the present invention attains a satisfactorily good purification result in all cases notwithstanding changes in process conditions, variations in the chlorophenols content of the intake water or other similar disturbing factors.
• the characterizing properties of the method according to the invention are disclosed in the annexed claims .
• purification of chlorophenol-containing water is carried out in parallel with the industrial conversion process of timber.
• the purification method disclosed herein is comprised of puri ⁇ fication steps each of which utilizes the conventional process steps of the industrial conversion of timber.
• the characterizing property of the invention is that the purification process steps are associated with the process steps (partial processes) of timber conversion in a manner that requires no extra investments by the saw mill.
• the stepwise purification method is adapted to the partial processes appropriately in series or parallel so that any possible disturbance in the actual timber conversion process, its auxiliary processes or the purification process itself have no appreciable effect on the final result of purification.
• purifica ⁇ tion of water containing chlorophenols can be achieved without extra equipment utilizing A) photolysis, B) adsorp ⁇ tion, C) bioreduction, and D) thermal decomposition.
• the purification of water is most advantageously implemented utilizing such auxiliary processes of timber conversion as 1) water-spraying of log piles, 2) intermediate storage of bark and 3) combustion of bark.
• a normal timber conversion (log sawing) process to which the invention can be applied is as follows:
• the logs are transported with bark from the woodlands to the saw mill.
• the logs are stored with bark in piles on the woodyard.
• the purpose of the log storage is to ensure uninterrupted operation of the saw mill with a suffi ⁇ cient supply of timber for approx. 1 - 6 months irre ⁇ spective of any delivery disturbances.
• - During the warm season, which in the Nordic countries is from May to October, the log piles are kept moist by continuous water-spraying.
• the purpose of water- spraying is to prevent insects from infecting the wood and thus causing considerable quality damage.
• Prior to sawing the logs are debarked.
• the bark is stored in heaps. Composting in the heaps heats the bark, whereby water contained in the bark is evaporated and the bark loses water.
• the bark is conventionally used in the power plant of the saw mill as a fuel for generating heat that can be used for drying the wood and heating the premises .
• the logs are sawn into planks and boards .
• the converted timber is sorted by dimension and quality. Green, freshly sawn timber becomes easily blue-stained by fungi and molds. To prevent this, the saw mill industry has used chemical agents to prevent blue-staining. The most common preservatives employed in the prior art contained chlorophenols .
• the chlorophenol-containing water introduced from a source into the decomposition process of chlorophenols is combined with the water circulation used for spray ⁇ ing the log piles.
• the chlorophenols are decomposed by a first reduction step of photolysis .
• the auxiliary process of water-spraying is utilized for the photochemical decomposition, or photolysis, of the chlorophenols contained in the water to be treated by subjecting the water to solar UV radiation.
• photolysis takes place as long as the supply of UV radiation is available.
• portion of the chlorophenols bound in the bark undergoes bioreduction as the bark is generally stored in heaps for up to several months prior to its use as a fuel.
• the bark or other absorbent behaves like a compost in which the internal tempera- ture is elevated by composting thus creating optimal conditions for a continued reduction of chlorophenols through bioreduction by naturally occurring bacteria or other microorganisms capable of biologically decomposing chlorophenols.
• the method described above always attains decomposition of chlorophenols by virtue of a novel method of utilizing the auxiliary processes of timber conversion without needing any extra equipment. Neither are the operating costs of a saw mill facility increased with regard to normal timber conversion. Moreover, the series and parallel connection of the different purification steps according to the invention assure that the decomposition of chlorophenols takes place with a sufficient efficiency even if operating disturbances would occur in the individual auxiliary or purification processes used in the method.
• the efficiency of the purification process can be further enhanced by adding more process steps or using proper additives where economically justifiable.
• the efficiency of the photolysis step can be improved by arranging a separate photolysis circulation for the "clear" chlorophenol-containing intake water prior to routing it to the more turbid circulation of the log pile spraying water.
• the higher effect of photolysis on clear water can be utilized.
• bioreduction step can be improved by seeding the bark heap with bacteria or enzymes obtained from separate cultures of microbes with a specifically high digestion capacity of chlorophenols. Also a controlled dosing of nutrients can be used to enhance bioreduction, while the risk of their detrimental effects via releases into waterways or emissions from the combustion step may simultaneously increase.
• Figure 1 is a flow diagram of the purification process in conjunction with the auxiliary processes of a saw mill .
• chlorophenol-containing water is routed to a spraying-water pond 1, wherefrom the spraying water is pumped by a pump 2 to spray nozzles 3.
• the water spray 4 is used for moistening the piles 5 of undebarked logs 5.
• the chlorophenols contained in the water are subjected to photochemical decomposition through photolysis.
• the spraying water enters the bark of the logs in the piles 5 and the chlorophenols contained in the water are adsorbed in the bark. This step utilizes the adsorption of the chlorophenols .
• the water flows along the ground 7 back into the spraying water pond 1.
• the microbes of the soil perform biological decomposition of the chlorophenols meeting the microbes.
• This step utilizes bioreduction by microbes .
• the bark separated from the logs is transferred to bark buffer heaps 9.
• the heaps can be further soaked with the overflow water 10 from the spraying water pond 1.
• Composting in the heaps 9 elevates the temperature of the bark and aids the evaporation of excess water from the bark.
• the bark heaps can be operated as biological composts in which the bioreduction of the chlorophenols is continued.
• the bark is transported to a power plant 12, where the bark is used for generating heat through combustion. When the combustion is carried out at a temperature greater than 850 °C using sufficient excess oxygen and retention, the chlorophenols still existing bound in the bark are thermally decomposed into nontoxic compounds .
• An essential property of the invention is that the purifi- cation of chlorophenol-containing waters is achieved by virtue of utilizing the existing processes of a saw mill, whereby investment in new machinery or equipment is not necessarily needed.
• the present method does not either require the use of additives such as chemicals-digesting bacteria, enzymes, nutrients or auxiliary chemicals.
• the investment and operating costs and hence also the threshold for initiating the purification operations remain low.
• the use of auxiliary equipment or materials is, however, possible in conjunction with the method when considered necessary and advantageous for improving the efficiency of the purification process.
• the method can be complemented with, e.g., an electrolysis, filtration or similar step.
• the mutual order of the process steps according to the method can be varied, and some of the steps can be added or removed as required.
• the purification method can employed in and adapted to the production layout of the saw mill and desired configuration of the purification process using the most appropriate sequence of the purification steps.
• the method according to the invention is primarily intended for purification of waters contaminated by a chlorophenol compound, whereby said waters can be routed to the purification process principally from outside the plant, e.g., from a contaminated waterway, aquifer or similar source. If the chlorophenol-containing chemical is used in the plant itself, the method according to the invention can as well be used for the purification of the in-plant chlorophenol-containing process water or similar contaminated water.

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8538050

Family Applications (1)

Country Status (3)

Cited By (3)

Citations (5)

• 1993
  • 1993-06-01 FI FI932500A patent/FI100521B/fi not_active IP Right Cessation
• 1994
  • 1994-05-31 AU AU67986/94A patent/AU6798694A/en not_active Abandoned
  • 1994-05-31 WO PCT/FI1994/000223 patent/WO1994027912A1/en active Application Filing

Patent Citations (5)

Also Published As

Similar Documents

Legal Events