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Three methods for composting, aerobic, anaerobic and mixed type were compared in three locally fabricated composters of 20 L each, for their effect in accelerating compost maturity and stability using municipal solid waste. The composting process was monitored through determining the changes in temperature, pH, ammonium-N (NH(+)4-N), nitrate-N (NO- 3-N), carbon/nitrogen (C/N) ratio, NH(+)4-N/NO(-)3-N, total carbon, nitrogen (TN), potassium (TK), phosphorous (TP), humification index (HI), degree ofpolymerization (DP), humification rate (HR), CO2, humic acid (HA), fulvic acid (FA), and cation exchange capacity (CEC). Temperature increased rapidly from the mesophilic to the thermophilic stage and gradually decreased near the maturation phase. A similar behaviour was recorded for pH, which become slightly alkaline at the maturity level. The composting process decreases the concentration of total carbon, NH(+)4-N, C/N ratio, and CO2, and increases CEC, HI, DP, HA, TP, TK, and TN. All three composting methods used in this study produce mature compost at different time intervals. A high statically significant correlation was found between the total carbons, C/N ratio, HA, FA, DP, HI, HR, CEC, and ammonium nitrate ratio.

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Phytoremediation is a green technology for the sustainable remediation of surface soils contaminated with toxic heavy metals. When added to soils the chelating agent ethylenediamine tetraacetic acid (EDTA) increased the solubility of heavy elements for plant uptake during phytoremediation. A greenhouse experiment was carried out with two Brassica species (Brassica juncea and Brassica carinata) grown on artificially contaminated soil (20 and 40 mg Cd kg-1) with EDTA added at a rate of 1 g kg-1 soil. With increasing Cd (0, 20 and 40 mg Cd kg-1 soil) contamination the biomass of both the Brassica species decreased. However, Brassica juncea was more tolerant of high levels of Cd in the soil in comparison to B. carinata. The results indicated that EDTA made the cadmium more available to the plants and lowered the Cd content of the soil. The magnitude of the increase in tissue (stem, leaf and root) Cd concentration was higher in B.juncea than in B. carinata and after the application of chelating agent (EDTA). The Brassica juncea species of Indian mustard has better potential for the phytoremediation of soil heavily contaminated with Cd (40 mg Cd kg-1 soil).

Because of its strong chelating capacity, application of ethylenediaminetetraacetic acid (EDTA) to soils may change the amount and distribution of heavy metals among their various chemical forms. Therefore, a greenhouse experiment was conducted using two cultivars of Brassica species (Brassica juncea and Brassica carinata) as hyper accumulator test crops on natural and artificially Cd and Ni contaminated soils. Both natural and metal amended soils were treated with disodium salt of EDTA at 0 and 1 g kg −1 soil. After harvest of crops, soil samples were fractionated into water soluble plus exchangeable (WE), carbonate (CARB), organic matter (OM), Mn oxide (MnOX), amorphous Fe oxide (AFeOX), crystalline Fe oxide (CFeOX) and residual (RES) fractions. In metal amended soils, Cd and Ni were found predominantly in the AFeOX fraction in the absence of EDTA application and in the WE fraction in EDTA treated soil. Application of EDTA resulted in the redistribution of Cd among different forms and increased significantly Cd in the WE fraction with a concomitant significant decrease in the OM fraction. In natural soils, more than 40% of the total Cd was present in the RES fraction while in contaminated soil it was only 5%. Nickel in the WE fraction increased significantly while it considerably decreased in the CARB, OM, MnOX, AFeOX and CFeOX fractions with EDTA addition. This indicated that applied EDTA is capable to move Cd and Ni from the less soluble or more stable forms (CARB, OM, MnOX, AFeOX and CFeOX) to the most soluble form (WE). N natural soils, Ni in the RES fraction was found upto 49%, whereas only 10% of the total Ni was observed in contaminated soil, irrespective of EDTA treatment. In general, the amount of Cd recovered after harvest of both the Brassica cultivars did not differ significantly in any fraction except the WE fraction. The amount of Ni recovered in the AFeOX fraction was significantly higher after harvest of B. juncea as compared to B. carinata.

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Municipal solid waste compost is an organic soil additive that can be used in agricultural production, improving soil physical properties, increasing both water retention and supply of essential nutrients. In this study three different types compost were studied. One produce by Lahore City Government second from Patoki compost and third from PCSIR Labs Lahore. These were analyzed for pH, conductivity, organic matter, total nitrogen, P 2 O 5 and K 2 O by using AOAC method. Average moisture, pH, carbon were highest in Patoki compost while organic matter was lowest (27%) in Paktoki and highest (56%) in PCSIR sample. Potassium was maximum in Lahore City Government and Patoki compost, minimum in PCSIR samples. The C/N ratio in all compost samples suggest that compost were stable and mature.The concentrations of Pb and Zn were also studied.