DUCKWEED BASED WASTEWATER TREATMENT SYSTEM AND ASSESSMENT OF NUTRITIVE VALUE AND ECONOMIC RETURN

With the objective to evolve a low cost treatment technology, the project has been undertaken to study the efficacy of treatment of wastewater by duckweed, to assess the economic return from pisciculture (fed on duckweed) as well as evaluating the nutritive value of duckweed.

The duckweed based stabilization pond functions as anaerobic pond except at the top layer where aerobic condition prevails. The top aerobic zone effectively controls the odour problems of the pond. The capability of up taking nutrients and other substrate from wastewater has attributed this plant to be biological purifier. There is remarkable reduction of BOD, COD, Total Suspended Solid, Nitrogen, Phosphorus and Heavy metals from wastewater in duckweed based stabilization pond. Wastewater treatment by duckweed based stabilization pond provides the treatment at a low cost. This type of treatment system can therefore help in meeting the challenges posed in developing countries for environmental protection, due to resource recovery advantages over the conventional lagoon system.

Publication:
• Guidelines for Duckweed Based Wastewater Treatment System:IMPACTS/7/2000-2001.

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APPLICATION OF DUCKWEED BASED WASTEWATER TREATMENT SYSTEMS

Duckweed could be successfully used for removal of pollutants from domestic wastewater. The optimum conditions for efficient treatment and design parameters has to identify in order to develop Duckweed based low cost treatment technology, the Central Pollution Control Board had sponsored the project on "Duckweed based wastewater treatment system" to M/s Sulabh International, New Delhi. On the basis of the findings of the study, the following potential application for the Duckweed based treatment system have been derived:

• Treatment of sullage of small communities (BOD 75-125 mg/l)

Duckweed based system can be used with the following additional advantages for small term generating wastewater with low BOD (range 75-125 mg/l).

- Highly skilled personals are not required in such places.
- No energy requirement for running of the unit.
- Income due to harvested duckweed fish feed, chicken or cattle feed.

Duckweed based Stabilization Pond

• Polishing of secondary treated effluent (BOD < 50 mg/l)

This treatment system is also suitable to give further treatment to effluents from algal waste stabilization ponds and mechanically aerated lagoons to meet the BOD and TSS regulations, especially when TSS are due to algal bio-mass.

Duckweed

• As a component of STP for a large town

Duckweed based ponds can be used as a component unit of the sewage treatment plant of a large town/ city for the purpose of removing residual organic pollutants, to provide enhanced denitrification, removal of heavy metals and inorganics, and also for generating revenue by utilising the duckweed bio-mass for economic gains to meet partial cost of operation of the STP. Duckweed pond as a component of STP of a large town may be financially beneficial because the cost of operation and maintenance of duckweed pond unit will be only a small portion of the cost of operation and maintenance of the entire STP.

Publication:

• Guidelines for Duckweed Based Wastewater Treatment System:IMPACTS/7/2000-2001.
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DEVELOPMENT OF ROOT ZONE TREATMENT TECHNOLOGY

CPCB in collaboration with GTZ, Germany has undertaken pilot study on Root Zone Treatment System for treatment of dairy effluent. The Root Zone Treatment System is artificially prepared wetlands comprising of clay or plastic lined excavation and emergent vegetation growing on gravel/sand mixtures.

To investigate the efficiency of root zone treatment system in warm climates, a pilot project has been set-up at Mother Dairy, Delhi to treat the dairy waste. The dairy wastewater, with average BOD of 800 mg/1 and BOD range from 8000 mg/l to 12000 mg/l was used for the experiment.

Root Zone Treatment Pilot Project at Mother Dairy, Delhi

The RZT data generated from the studies will form the basis of guidelines being developed for RZT System. A committee has been constituted under the Chairmanship of Dr. K.R. Ranganathan, Member Secretary, Loss of Ecology (P&C) Authority for the State of Tamil Nadu to develop "National Guidelines for construction, use, operation & Maintenance of Root Zone Treatment System" in India. The Committee consists of members from CPCB and Experts from GTZ project, UNIDO project, Chennai, Kraft & Associates, Pondicherry, Centre for Scientific Research, Auroville, IRSBB, Chennai etc. The applications of root zone treatment technology are:

• Treatment of domestic wastewater especially for small towns, villages is easily possible & affordable having low investment.

• RZTS can also treat biodegradable industrial effluents specially effluents of agro-based industries.

• RZTS Technology can be applied in Urban Watershed Management (UWM) through following ways:

• Transformation of urban open nullahs into cleaner streams through decentralised RZTS.

• Cost reduction for wastewater treatment through improved self-purification of restored streams.

Construction & Laying of Geo-textiles & Filter Media for Root Zone Pilot Project

A number of Root Zone Treatment System (RZTS) plants have been set-up in India by private companies at places such as Auroville, Chennai, Pune, Tekkadi (Kerala), Bhopal, Gurgaon, & Bilaspur (MP). CPCB has sponsored a project to Centre for Scientific Research, Auroville to monitor their four such plants for a period of one year.

Publications:

• Root Zone Treatment Technology - Brochure.
• Constructed Waste land for Wastewater Treatment: RERES/2/2001-02.
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ALTERNATE TECHNOLOGIES FOR POLLUTION CONTROL IN VINYL SULPHONE INDUSTRY

To suggest process modifications and technologies for better pollution control from vinyl sulphone industry, the project has been taken up in collaboration with National Chemical Laboratory, Pune. The project is in progress.
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TECHNOLOGY DEVELOPMENT OF SPECIFIC MICROBIAL PACKAGES FOR TREATMENT OF PAPER & PULP INDUSTRIAL WASTEWATER

The efficiency of treatment of industrial wastewater depends upon the composition of chemicals and their reaction with microbial action on the wastes. There are specific groups of bacteria, which act effectively with specific types of waste and degrade the waste in a fast and efficient manner. Keeping this fact in view, the project has been taken up in collaboration with the Centre for Biochemical Technology (CSIR), Delhi with sponsorship from the Department of Biotechnology, New Delhi.

The Paper mill effluent was collected, analyzed and characterization has been made for screening the suitable and efficient bacterial composition. Trial runs were made to find out the degradation rate of the microbial package using the effluent. The outcome of the project work will be helpful in development of special microbial package, which will treat the paper & pulp wastes effectively in terms of time and pollutants like BOD, Lignin, Colour, AOX, TDS etc.
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DEVELOPMENT OF TECHNOLOGIES FOR POLLUTION CONTROL AT DRUG MANUFACTURING UNITS - PARACETAMOL A CASE STUDY

Paracetamol is an important drug manufactured in the country and is being used as an analgesic and antipyretic drug in a number of formulations in the form of tablets, powder, granules and injectibles. Paracetamol is produced from para nitro phenol using iron-acid for hydrogenation as a result huge amount of hazardous waste is generated with high organic impurities, which are difficult to dispose. Since, the scale of operation is very small and it will be very difficult to dispose the wastewater even in common hazardous waste disposal site, it will be worthwhile to employ catalytic hydrogenation or any other cleaner options so that the effluent / emission/ hazardous waste generation can be minimized. Such an attempt with respect to H-acid and vinyl sulphone provided us insight for cleaner production and waste minimization.

The objective of this study comprises the development of cleaner production process for manufacturing of paracetamol, improvement in the efficiency of production, cost reduction and waste minimization.
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CONTROL OF TOTAL DISSOLVED SOLIDS IN INDUSTRIAL EFFLUENTS

CPCB along with National Chemical Laboratory (NCL), Pune is studying various industrial effluent streams, process modification required to avoid/reduce Total dissolved solid generation, control equipment and their feasibility from major industries like pesticides, bulk drugs, tanneries, dye & dye intermediate manufacturing industries. The control technologies available for TDS control have been compared and their merits and limitations are being studied.
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CONTROL OF OFFENSING ODOUR SUBSTANCES WITH SPECIFIC REFERENCE TO SELECTED INDUSTRIAL PROCESSES

The presence of malodours in and around organic chemical industries is an unpleasant but seemingly ubiquitous fact. Constituents of malodour are generally volatile hydrophobic molecules containing one or two functional groups made up of elements such as oxygen, sulphur, and nitrogen. Sometimes the presence of ammonia imparts odour. The off odours in the vicinity of the pharmaceuticals are mainly due to the presence of amines, hydrogen Sulphide and mercaptans. In case of antibiotics unit the odours are mainly due to thiazole, azines and lactans. In pesticide industries, odours are imparted by phosphorous, sulphides as well as chlorides. In dye and dye intermediate industries, odours are due to metal reductions, amination, coupling reactions using metals. In case of fine chemicals and bulk drugs, the odours are due to sulphur and nitrogen compounds, unsaturated olefins and several other organic reaction end products. Most of the constituents of the malodours are highly toxic gases, which can be fatal. They are irritants to respiratory system and eyes, causing damage to nervous, gastrointestinal system and skin at higher concentrations.

Typical Atomizer for Odour Control

The objective of the project study includes enlisting priority offensive odorous substances in the country, identification of method of odour detection and choice of control technology (BAT & BPT) for enlisted offensive odorous substances, setting norm for control of specific offensive odour substances from selected industrial processes.

Publication:

•Odour Pollution and its Control; CPCB Newsletter, January 2003.
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A BENCH SCALE MODEL STUDY ON TREATMENT OF TEXTILE WASTEWATER

Textile industries contribute considerable amount of effluent of varying characteristics the effluent carries colour, dissolved solids and various organic and inorganic substances. Treatment of the textile effluent normally involves neutralization, coagulation followed by biological treatment. This treatment involves large amount of acid, coagulants and energy. In order to over ride high amount of chemicals, an attempt has been made to treat textile effluent by highly acclimatized microbial composition. It has also been observed that the acclimatized mixed culture shows maximum efficiency in term of pH reduction and removal of COD and TDS. Using the acclimatized microbial culture, the remaining part of the COD from the primarily treated effluent, can be further reduced to 60-69% with an improvement upto 40 % reduction in the Total Dissolved Solids contents.

Publications:

• Biological Treatment of Textile Mill Effluent - A Case Study: IMPACTS/5/1999-2000.
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TREATMENT OF PRIMARY AND TREATED DISTILLERY EFFLUENT IN BATCH AND FEED BATCH MODE IN AEROBIC ENVIRONMENT

Wastewater from distillery contains large amount of dissolved organic matter and possesses high pollution loads in terms of BOD. This organic matter is readily decomposed by microbial action and consequently discharge of these wastes to surface water causes serious damage to the aquatic life in water resources. The project study has been undertaken to find out how much treatment can additionally be given to anaerobically treated effluent.

Primarily treated distillery effluent was taken as sample effluent to study the extent of degradation of pollutants in batch and feed batch mode in laboratory scale reactors. The experimental system was initially fed with known amount of activated sludge and constantly aerated. In batch reactor, no replacement was made; however, in feed batch reactor the amount of sample withdrawn replaces the fresh sample. Temperature of the reactors was maintained by keeping in temperature controlled water bath. All the reactors were seeded with acclimatized mixed culture. At constant aeration and temperature, samples are withdrawn from all the four reactors and analysed for BOD, COD and Total dissolved solids.

The findings of the treatment study indicate that the BOD of the sample was reduced down to 360 mg/l from the initial level of 2130 mg./l. The COD of the sample was also reduced to 7480 mg/l from the initial level of 19800 mg/l and the Total Dissolved Solid (TDS) content of the effluent was reduced to 6330 mg/l from initial level of 18340 mg/l.
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DYE DECOLORIZATION BY ACCLIMATIZED MICROFLORA

Generally dyes are the coloured compounds, which are capable of being fixed in fabric and are classified based on their application. The dyes are of special environmental concerns because of their carcinogenic nature, formation of toxic amines, persistency and recalcitrant nature. Dyes like Astrozan blue, Maxilon red, Telon blue, Congo red, Solar blue, Faron blue, Safranine, Faron brilliant red, Sandolan, Rhodine were tested for microbial degradation by Batch process. Among all the tested dyes, it has been observed that eight dyes were readily degraded by the acclimatized micro-flora, when the concentration of individual dyes increase from initial 5 ppm to final 50 ppm. Further studies are in progress.
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STUDY ON BIODEGRADATION OF SYNTHETIC DYES IN TEXTILE INDUSTRY

Presence of various types of dyes & chemicals make the textile effluent coloured and highly alkaline. To treat such type of effluent, conventional and cost effective treatment methods are acid neutralization, flocculation and adsorption.

To replace acid neutralization by other possible process, the project has been designed and undertaken. The study includes characterization of the textile effluent, acclimatized culture development, flocculation/coagulation treatment of combined effluent for primary treatment, treatment of primarily treated effluent at laboratory scale. Developed micro flora and freshly collected activated sludge, suitability of laboratory developed micro flora for wastewater from a problem area.

Acclimatized micro flora developed in the laboratory has been studied in the shake flask for pH change and COD reduction. The sequence of various coagulants in various combinations was tested for best reduction of pollutants.
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DECOLORIZATION OF SYNTHETIC TEXTILE DYES USING NATURAL LOW COST ADSORBENTS

A number of naturally occurring adsorbents like Water Hyacinth roots, shoots of Hydrilla plants, bagasse, orange peels, saw dust were tested for different synthetic textile dyes in batch mode and compared with activated charcoal. The dyes such as Astrazon blue, Maxilon red, Telon blue, Caongo red, Methylene blue, Malachite green, Victoria blue. Solar blue, Foran blue, Safranine, Faron brilliant red, Sandolan, Rhodine using different adsorbents and adsorption capacity for each dye adsorbent system has been evaluated in aqueous system. Parameters studied include pH, sorbent dosage, contact time and initial concentrations. The performance of different adsorbents for majority of dyes was observed as Hyancith root < Hydrilla plant < Hyacinth shoot < saw dust < orange peels < bagasse. The pattern of maximum removal of majority of dyes was observed as Methylene blue < Malachite green < Congo Red < Safranin < Maxilon red <Telon blue < Faron brilliant red < Victoria blue < Astrazon blue.
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ENVIRONMENTAL IMPACT OF SILICA SAND MINING AND WASHING INDUSTRIES

The environmental impact of silica sand mining and washing studies has been undertaken in association with Directorate of Geology and Mining Allahabad. The project study involved inventory and detailed status of pollutant from silica sand mining and washing industries at U.P., Haryana, Karnataka, Maharashtra, Bihar, Rajasthan and Gujarat. It has been derived that there is no organized management of silica sand mining practices and its excessive abstraction, which increases the risk of ground water pollution. The indiscriminate mining, lack of effluent treatment provision and improper disposal of high iron sludge from these operation may lead to environmental degradation.
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TREATABILITY STUDY ON INDUSTRIAL EFFLUENT CONTAINING DDT PESTICIDE

The persistent pesticides in the wastewater have created serious ecological problems, as they transfer in food chain through successively higher organisms accumulating increasingly concentration at each level, causing effects to the producer at the end of predator chain. DDT is one of the most persistent organo-chlorine pesticide used for agriculture, public health and veterinary purpose.

The wastewater resulting from DDT manufacturing unit is not possible to treat directly by biological treatment process, some physico-chemical pre-treatment is essential to reduce toxicity before its biological treatment. It was observed that to reduce toxicity of wastewater from DDT Pesticide manufacturing unit, dilution practice has been followed before biological process. The dilution process requires huge amount of fresh water, therefore alternative treatment to remove toxicity from wastewater to a considerable extent was envisaged so that treatment could be achieved with no dilution or little dilution.

The objectives of the study are:

- Modification in conventional chemical treatment with cost effective treatment technology.

- Biological treatment of chemically treated effluents without dilution (as practiced in ETP's) of pesticide industries.

To overcome the problem of dilution by freshwater to reduce the toxicity, single, mixed-sequential coagulation systems was adopted. By using sequential coagulation system 47 % of toxicity removal in the effluents was achieved. The chemical oxidation (using oxidants H2O2, KMnO4) followed by sequential coagulation, by using Fenton's oxidation system 38% of toxicity was removed. After coagulation and oxidation (by Fenton's oxidation) the effluent was treated biologically diluting it with sewage water in 1:1 ratio and the treated effluent complied the effluent discharge standard limits.
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SLUDGE REAGENT PRODUCT (SRP) TECHNOLOGY FOR WATER AND WASTEWATER TREATMENT

In this project study, new treatment technology has been developed for treatment of raw water using discarded sludge from conventional water treatment plants. The developed process technology has been applied for treatment of water. The alum treated sludge is reused as alum again after chemical treatment. Thus, the volume of sludge reduced to 70-80% in comparison to conventional treatment technology. Water recovery was almost 99% and alum consumption 10-20%.

SRP Technology-Laboratory Set- up at CPCB Laboratories

The SRP Technology has been used for treatment of wastewater in which different types of commercial alum have been used as single and in sequential manner for treatment of drain water. The quantity of coagulant to be added to the sludge reagent product (SRP) to maintain 100% efficiency of the continuous treatment process were determined. The water treated with conventional technology as SRP were characterized and treated water quality was compared with drinking water quality standards. Comparison of cost for the conventional and SRP technology was performed comprehensive assessment of the findings was made and patent was filed. Based on SRP Technology 0.5 MLD pilot plant has been installed at Bhagirathi Water Treatment Plant for which Memorandum of Understanding has been executed with Delhi Jal Board.
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BIOLOGICAL REMOVAL OF TRACE AROMATICS FROM DRINKING WATER AND INDUSTRIAL EFFLUENTS BY IMMOBILIZED PEROXIDASE AND TYROSINAGE ENZYME

The enzymes are commonly used as biocatalysts for industrial process and clinical purpose. The enzymatic approach to remove toxic chemicals from drinking water and industrial wastewater has received much attention recently. The enzymes such as peroxidase and tyrosinage are extensively used for biotechnology purposes as well as removal of organic pollutants like phenols, colourants from industrial wastewater. During the process, the enzyme gets inactivated after initial reaction, therefore it has to be reactivated, which increase the cost of process. To reduce the cost, immobilization of enzyme is necessary by which it leads to high storage stability and better control of catalytic process.

Bioreactor for Biological Removal of Trace Aromatics By Enzymatic Action at CPCB Laboratories

The main objective of the project is to develop viable process for extraction of peroxidase enzyme from plant sources, such as radish roots and mushroom. The purification of crude extract of enzyme, stabilization of purified peroxidase and tyrosinase enzyme and development of optimized process for immobilization of enzymes. The purified and immobilized enzymes are proposed to be used to remove organic pollutants like phenol, pesticides, amines from drinking and industrial wastewater. The peroxidase enzyme has been extracted by homogenization and centrifugation from plant sources. Further studies are in progress.

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