Toxicity Studies of Waste Water

·        Studies have been undertaken under a project on "Development of Toxicity Based Standards for Textile industries and Pulp & Paper Industries". The effluents were collected from various Textile and Pulp & paper industries in collaboration with Gujarat State Pollution Control Board, Gandhinagar; NEERI, Nagpur; CPCB Zonal Office, Kanpur and National Institute of Occupational Health, Ahmedabad.

·        Toxicity test method developed by CPCB has been recognized and adopted by the Bureau of Indian Standards (BIS) New Delhi and published as “Bio-assay Method for Evaluating Acute Toxicity of Industrial Effluents & Wastewater – Part 2 using Toxicity Factor to Zebra Fish (Brachydanio rerio)” as IS-6582 (Part 2):2000.

Water Quality Monitoring of River Yamuna/Ganga

·        Water quality monitoring of river Yamuna was carried out at 15 monitoring stations from Hathnikund to Chambal river confluence, as well as from 12 major drains joining river Yamuna for nine physico-chemical parameters (monthly), five pesticides (quarterly) and seven heavy metals (monthly). 

·        Monitoring of river Yamuna and its tributaries under MINARS project was carried out on quarterly basis at three upper stretch locations and at Allahabad. Monitoring has also been carried out at source and its downstream at two locations in the month of June.

·        Regular monitoring of river Yamuna and various drain outfalls at river Yamuna in Delhi stretch has been continued on monthly basis as per Supreme Court directions. The analysis results in form of affidavits have been periodically submitted to the Hon’ble Supreme Court.

·        Monitoring of Ganga and its tributaries has been carried out under MINARS project at ten upper stretch locations. River Ganga has also been monitored near its origin source (Gangotri) in the month of June.

Water Quality Status of River Yamuna in Delhi Stretch

The water quality of river Yamuna from origin upto Delhi u/s Wazirabad remains fairly good most of the time, while the river stretch from downstream Wazirabad Delhi to upstream Chambal confluence to the river carries deteriorated water quality mainly because of contribution and impact of urban centers located on its back. Out of 341 km stretch, 22 km of Delhi segment is the most polluted. The main reason of pollution in this segment is the discharge from domestic and industrial sources. The Central Pollution Control Board is regularly monitoring Yamuna on monthly basis in Delhi segment at three locations i.e. Palla, Nizamuddin barrage and Okhla barrage. In addition, monitoring of 22 drains, which are the major source of pollution in the river are also being undertaken regularly. The water quality of drains and Yamuna in Delhi stretch is depicted in table. The total calculated discharge of these 22 drains is approx. 46.30 m³ /sec, which contributes 311.05 tonnes of BOD load per day. From the total discharge of these drains Yamuna receives more than 90% wastewater discharge and rest wastewater contributed by two drains joins canals. Similarly, out of 311.05 tonnes of BOD Yamuna receives 283.98 tonnes of BOD per day and rest received by canals. The Delhi segment of river Yamuna has oligotrophic head and saprobic tail end, and characterized by high bacterial load (except at Palla location its appearance is cloudy) having high BOD with strong disagreeable odour. The anaerobic condition in the river is frequently reflected by masses of gaseous sludge rising from the bottom and floating on the surface of water.

 (January – December 2001)

Water Quality of River Yamuna in Delhi Stretch (22 Kms.)

(January – December 2001)

Min = Minimum;                   Max = Maximum;                  Av = Average

Delhi's Wastewater Management

Central Pollution Control Board is regularly monitoring water quality of the Yamuna river and all the wastewater drains joining it. Some of the important findings are presented below.

As per latest monitoring result of CPCB, Delhi generates about 2700 MLD of wastewater out of which treatment capacity has been created for 1927 MLD. Thus, at present a major portion of sewage generated at Delhi remains untreated.

Another problem identified in the study is non-availability of clean water in the river. Almost all the clean water is withdrawn at Tajewala and subsequently at Wazirabad for irrigation and drinking respectively. Only 10 cumecs of flow is maintained downstream Wazirabad in compliance with Hon'ble Supreme Court's order.

It is estimated that more than 400 cumecs of clean water with BOD of 2 mg/l is needed to dilute the treated sewage (with BOD 20 mg/l) of Delhi joining the river Yamuna between Wazirabad and Okhla barrage.

Total water available in the river is only 90-130 cumecs during dry months and 520 cumecs in monsoon months, 80% of which is used by Haryana and Uttar Pradesh for irrigation. Thus, there is no possibility of providing dilution to the discharged wastewater to the bring the water quality of river Yamuna to desired level.

An option suggested by CPCB is to have a parallel channel along the right bank of the river, which may receive all wastewater drains between Wazirabad and Okhla barrage and transport the wastewater to Agra Canal.

Status and Performance of Sewage Treatment Plants in Delhi

Performance monitoring of nine sewage treatment plants was undertaken under a sponsored project of the Delhi Jal Board since October 2000 on monthly basis. Grab samples of wastewater were collected from Influent and Effluent Channel of STP's and analyzed for various physico-chemical parameters including heavy metals and pesticides. In addition, STP sludge was also analyzed for various heavy metals and pesticides regularly.

In most of the STP’s, the percent reduction in BOD, COD & TSS load was more than 85%. Most of the STP’s have been operating under-capacity. The status of STP’s, which are under construction/ installation is given in the following table.

(As on August 2001)

Estimated Wastewater Generated                               =              594 MGD (2700 MLD)

Actual Wastewater Treated /Operational

Capacity of STP’s                                                      =              343.75 MGD (1563 MLD)

Present STP’s Installed Capacity                                 =              432.6 MGD (1966 MLD)

Capacity under Construction                                        =              80 MGD (364 MLD)

Performance Evaluation of Sewage Treatment Plants

Performance monitoring studies of five sewage treatment plants viz. one each at Delhi, Ballabhgarh and Gurgaon and two STP’s at Faridabad were undertaken on 24 hrs – 2hrly basis and monitoring reports forwarded to NRCD/MOEF. Performance monitoring studies of the sewage treatment plant Noida were also undertaken for the U.P. Jal Nigam, Noida. Performance of two oxidation ponds at Brindavan was monitored continuously for one year as requested by U.P. Jal Nigam.

Biomonitoring of Water Quality

Bio-monitoring has been undertaken in water bodies of following problem areas in collaboration with concerned Zonal Offices and State Pollution Control Boards:

-     Manali in Tamilnadu

-     River Hasdeo and Korba in Madhya Pradesh

-     Parwanoo and Kala-Amb in Himachal Pradesh

-     Najafgarh Drain Basin, Delhi

-         Howrah & Durgapur in West Bengal

-         Dhanbad in Bihar

-     Bollaram Patancheru at Hyderabad, Andhra Pradesh

-     Bhadravathi in Karnataka

Quantum of Municipal Sewage & BOD Load from Industries

A State-wise assessment on discharge of untreated wastewater in water bodies has been made by CPCB. For this assessment, the figures for wastewater generation and its treatment were projected for the year 2001and it has been derived that a total of 16,961 million litres untreated wastewater is generated per day in the country. The share of Maharashtra in this respect is 4193 million litres per day, followed by West Bengal, Uttar Pradesh and Bihar.

The assessment of the BOD load contribution by industries show that industries generate a total of 9478 tonnes of BOD load per day through raw effluent. After treatment this load comes down to 1775 tons per day. State-wise assessment reveals that Maharastra contributes maximum BOD, closely followed by Uttar Pradesh and Tamil Nadu.

Status of Domestic Wastewater Generation and Treatment  

(Projected Figures for 2001)

State-wise distribution of BOD Load (Tonnes/day) generated from various categories of Industries

Bio Mapping Of River Ramganga

CPCB has undertaken a study for preparation of a map on biological quality of River Ramganga during the year 2001-2002. Under this study, monthly monitoring (except July to September, due to monsoon flooding) at ten locations has been started in April 2001 and it is to be completed in March 2002. The data collected so far for Diversity Indices and Saprobity Indices are presented in following table.

Diversity Indices and Saprobity Indices in different locations on River Ramganga

Note: A - Clean; B - Slighty polluted; C - Moderately polluted; D - Highly polluted;

E – Severely polluted

* Monitoring conducted once

Rainwater Harvesting (RWH)

Rainwater harvesting (RWH) is emerging as a sustainable strategy to cope with the increasing pressure on scarce freshwater resources. In keeping with the strategy to promote water resources management and conservation, a demonstration project for installation of a simple rooftop rainwater harvesting and artificial recharge system within the premises of CPCB has been taken up. The system was installed within a period of 6 weeks, and was inaugurated on 12^th August, 2001, by the Chairman, Central Board.

Salient features of the installed RWH system:

Total cost of the project                                : Rs. 2.75 lakh

Total area of roof catchment                        : 1400 m²

Quantity of rainwater harvested                   : 1000 m³/year

Size of groundwater recharge pit    : 7mX 11mX 1.5m

No. of gravity-fed injection bores     : 5

Size of Injection bores                                  : 200 mm

Depth of groundwater table             : 5.2 m BGL

Equivalent economic benefit of

Harvested rainwater                                    : Rs. 45,000/year

Pay back period                                         : 15 years

Design life of the system                              : 25 years

A document entitled, "Concepts and Practices for Rainwater Harvesting" has been published for dissemination of technical information for design of rain water harvesting systems.

Constructed Wetlands for Wastewater Treatment

In recent years, constructed wetland systems have emerged as one of the low-cost, high performance wastewater treatment technologies in many European and American countries. There is a growing interest in India as well to develop and adopt this technology for water pollution control in India. However, there is lack of information and understanding of the concepts of treatment wetlands. In order to bring broader understanding of the concepts of treatment wetlands and wider application of this technology, a technical document has been prepared and published by the Central Pollution Control Board under the Resource Recovery Series. It provides a detailed overview of the concepts, pollutant removal mechanisms, engineering design, construction, operation and maintenance of constructed wetlands for wastewater treatment.