Case Study SADASAT

SADASAT CORN PRODUCTS PRIVATE LIMITED

1. RATIONAL: Sadasat Corn Products manufactures Maize Starch by “Wet Milling Method”. The wastewater generation from this industry is Spent Maize Carrying Water, and Maize wash water. During processing “Corn Steep Liquor”(CSL) is one of the by-product. World wide it is being mixed with bran and sold as cattle feed. But in India it is termed as waste and released along with wastewater. CSL contains both carbohydrate and protein in considerable quantity. It also contains Minerals, Vitamins etc. Thus the organic load becomes very high. It is acidic (pH around 4.2). When it enters ETP along with other wastewater the sample shows very high COD and BOD values (as tabulated below).

2. OBJECTIVE: To achieve the following

i. All parameter under permissible limits as per State Pollution Control Board norms.
ii. Low capital Cost.
iii. No Chemical Consumption.
iv. Lower space requirement.
v. Easy to Operate and Handle.
vi. Less sludge generation.
vii. Low power consumption.
viii. Low operating & maintenance cost.

3. TECHNOLOGY:

The technology is an integration of Bio-Technology and environmental Engineering . To handle such a strong effluent, Anaerobic digestion (UASB) has been considered followed by two stage Diffused Aeration. As inoculums a very efficient microbial consortium (Nature Vel-WW) has been used.

4. METHODOLOGY FOR OBJECTIVE ACHIEVEMENT:

The effluent water passed through all the components, and in the anaerobic digester there is a system of recirculation, from UASB outlet to UASB inlet tank (Buffer Tank). The purpose of this circulation is to initiation of organic load degradation, and pH adjustment. Thereafter the system has two numbers of Diffused Aeration Tank. These aeration are on the principle of step feeding. The bio-engineering was done in such a way that these aeration chambers can act as aeration cum settling tank. Here the powerful culture has a prominent role. These culture imparts good settling characteristics of the sludge. Thus the secondary settler has been eliminated which has reduced the capital cost by 23%. (Rs.13.8 lacs)

5. DESIGN BASIS:

i. Treatment Capacity: The Effluent treatment plant and recycling system is designed to treat 200.0 KLD of raw Effluent. The treated effluent shall be used or discharged into the drain at downstream side so as to reuse in the horticulture, floor washing agricultural field etc. Another useful utilization recommended was to sprinkle over boiler ash.

ii. Characteristics of Incoming Effluent: The Effluent characteristics considered for the design purpose of the plant as mentioned in following table.

Parameter Unit Raw wastewater (Average) Treated Water (Average)
Design flow m3/d 200.0 198.0
Design flow m3/h 8.33 8.2
Design Temperature °C 16 / 35 25
COD mg/l  81,562 120
BOD5 mg/l 28,000 27
TSS mg/l 30,000 86
Oil and Grease mg/l 10 BDL
pH 6.0-9.0 8.2